US 6058315

I'll run targeted searches for this patent number and its US docket presence.

Search coverage and caveats

I ran web searches aimed at the patent number, the patent title, and CAFC/litigation dockets. What I could and could not establish:

• Patent record: Multiple independent sources (Google Patents, Espacenet bibliographic + INPADOC, EveryPatent) return the same single document for "6058315" — US 6,058,315 A, "Speaker assembly for a radiotelephone."
• CAFC 2026 / district-court docket: I found no Federal Circuit appeal, PTAB proceeding, ITC action, or district-court case tied to US 6,058,315. The only non-patent hits for the bare string "6058315" were: (a) a U.S. Customs & Border Protection ruling, N363765 (Aug. 4, 2026), concerning SKU# 6058315, "Christmas Cow," an iron decoration — an unrelated commercial identifier; and (b) assorted docket documents that merely contain similar digit strings. Neither relates to this patent.
• Method limitation: I do not have direct authenticated access to the USPTO Patent Center/PACER/CAFC APIs in this session; my clearing of the docket question rests on public web search. Treat "no litigation found" as a well-supported negative, not a certified one. Note also that the patent's term has expired (anticipated expiration 2016-03-13), which makes current litigation unlikely.

Bibliographic data (US 6,058,315 A)

Abstract

As published: A speaker (302) is arranged in an enclosure formed by a front housing portion (200) and a rear housing portion (202), so that an air gap exists between a diaphragm (314) of the speaker and ports (114) formed in the front housing that face the diaphragm. The air gap provides an acoustic leak into the enclosure, which makes the frequency response of the speaker relatively independent of the seal formed by a human ear and the front housing portion. Sound-absorbing material (304, 300) disposed on either side of the speaker, ports that extend beyond the circumference of the speaker, and a filter (600) can be added to further enhance audio quality.

Plain-language overview of the independent claims

Claim 1 — the core structural claim (a radiotelephone). Four elements must all be present:

1. A front upper housing portion with a front surface and a rear surface. The rear surface is divided into two distinct "porting areas" (a first and a second), each of which has at least one port running from the front surface through to the rear surface.
2. A rear upper housing portion positioned relative to the front portion so the two together form an enclosure.
3. At least one standoff carried on the rear surface, positioned around the first porting area — and notably recited as "having portions of different heights."
4. A speaker resting on the standoff(s), spaced a predetermined distance from and covering the first porting area. This spacing creates an air gap between speaker and front housing, and creates a passage for air to leak from that gap into the enclosure.

The final clause is the point of novelty relative to ordinary sealed earpiece designs: the second porting area must not be covered by the speaker — i.e., there must be a port region open to the enclosure beyond the speaker's footprint.

Claim 8 — a second, more specific independent claim (a radiotelephone). Same general architecture as claim 1, but with these differences: both areas have a plurality of ports; there are a plurality of standoffs protruding from the rear surface and surrounding the ports in the first area; the speaker is recited as having a diaphragm facing the ports in the first area; and the claim expressly recites that an air passage is created for air to leak from the air gap into the enclosure, with the second area's ports uncovered by the speaker.

Dependent claims (for completeness)

• Claims 2–7 depend from claim 1: a low-pass electric filter (2); a complex 2-pole low-pass filter (3); sound-absorbing material between the speaker and one of the porting areas (4), optionally attached to the rear surface and covering a porting area (5); sound-absorbing material between speaker and rear upper housing portion (6), optionally attached to that portion (7).
• Claims 9–11 depend from claim 8: complex 2-pole low-pass filter (9); sound-absorbing material between speaker and rear upper housing portion (10); sound-absorbing material between speaker and front upper housing portion (11).

Supporting details in the specification: the preferred low-acoustic-impedance dynamic speaker is Hosiden model no. HDR 0970; the filter values recited are capacitor 614 = 0.1 µF, resistor 612 = 18 kΩ, capacitor 610 = 0.033 µF, resistor 608 = 10 kΩ, resistor 604 = 18 kΩ, capacitor 606 = 1000 pF, coupled with differential amplifier 602.

Prosecution context / cited art

20 references were cited of record (examiner and/or applicant), including GB 1295363 A; US 3,952,159 (Zenith, ducted port reflex enclosure); US 4,029,170 (B & P Enterprises, radial sound port speaker); US 4,427,583 and US 5,014,346 (both Motorola); US 5,168,527 (LZR Electronics, "Miniature speaker variable standoff mount"); US 5,369,701 (AT&T, compact loudspeaker assembly); US 5,668,867 (NEC, foldable portable telephone); and US D385,873 (Motorola housing design). Two non-patent citations are the E. Kerschbaum / AKG Acoustics Dynamic Transducer IXMR specification, Revision #3, June 22, 1995.

Bottom line

US 6,058,315 is a 1996-filed, 2000-issued Motorola patent (now Google Technology Holdings LLC) by Joel A. Clark covering a radiotelephone earpiece arrangement in which the speaker floats on standoffs a controlled distance off the ported front housing, deliberately leaking sound into the enclosure so audio quality is tolerant of a poor ear-to-housing seal — plus open porting beyond the speaker footprint, sound-absorbing felt fore and aft, and an optional 2-pole low-pass preconditioning filter. It expired in March 2016, and I found no CAFC or district-court activity associated with it.

I'll search for litigation involving US patent 6058315 across patent litigation databases.

The initial searches returned only a customs ruling (SKU# 6058315) and the patent itself — not litigation. Let me search the specialized litigation databases.

Let me run a few more targeted checks, including Docket Alarm/Justia litigation tabs and CourtListener.

Conclusion up front

Based on my searches, no litigation is known involving U.S. Patent No. 6058315. I could not identify any district court case, CAFC appeal, ITC Section 337 investigation, or PTAB (IPR/PGR/CBM) proceeding in which US6058315 was asserted, challenged, or otherwise at issue. Because the absence of a record is not the same as proof of absence, I have set out below exactly what I checked, where the search came up empty, and the caveats.

Patent identification (for the record)

Ownership chain (per the assignment records): Motorola, Inc. → Motorola Mobility, Inc. (eff. 2010-07-31) → Motorola Mobility LLC (name change, eff. 2012-06-22) → Google Technology Holdings LLC (eff. 2014-10-28).

What I searched and what was found

1. 6058315 patent litigation and "6058315" patent lawsuit — returned the patent's own Google Patents page, the Justia patent page, and Espacenet/INPADOC, plus U.S. Customs & Border Protection Ruling N363765 (Aug. 4, 2026). The CBP ruling is a false positive: its "SKU# 6058315" is an iron Christmas Cow decoration, unrelated to the patent. I flag it explicitly so it is not mistaken for a patent reference.
2. "US6058315" OR "6,058,315" litigation case docket — returned Espacenet status data, PTAB papers citing other patents, and CAFC decisions involving entirely different patent numbers (e.g., the ZOLL/Philips and Click-to-Call line of cases, which concern the '454, '905, '927, '978, '212, '879 patents). Nothing naming the '315 patent.
3. portal.unifiedpatents.com litigation 6058315 — Unified Patents content surfaced only as generic IPR-policy material (amicus briefs, PTAB petitions on unrelated patents). Unified's caselist portal did not surface the '315 patent in the result set.
4. Motorola patent 6058315 infringement lawsuit speaker assembly radiotelephone — returned Motorola/VTech, Blue Sky Networks v. Lenovo/Motorola, and ImberaTek complaints. In each, the patents asserted are different numbers. The '315 patent is not among them.

Negative-evidence indicator: the full Google Patents record for US6058315A contains no Litigation section. Google Patents normally populates such a section (listing case names, courts, and docket numbers) when it has litigation data for a patent. Its absence is consistent with there having been no recorded assertions. The record does contain a rich "Cited By" list (18 entries) and "Families Citing this family" (6 entries), but those are patentability citations by later applicants/examiners — e.g., US6321070B1 (Motorola, 2001), US6785395B1 (Motorola, 2004), US20070071267A1 (Samsung), US9807210B2 (Panasonic) — not litigation.

Caveats on confidence

• I could not reach paywalled/authenticated litigation sources directly: PACER requires a login, Docket Alarm and RPX Insight are subscription-gated, and Unified's caselist portal is best queried interactively; the search layer returned only public excerpts.
• The patent expired on 2016-03-13 and the term was never extended. Any assertion would therefore necessarily pre-date mid-2016 (a cause of action could not accrue after expiry). An exhaustive check would cover roughly 1996–2016 district court filings by Motorola, Motorola Mobility, or Google, and any 2012–2016 IPR filings (IPR only became available 2012-09-16).
• Third-party (non-examiner) citations I saw did not include any litigation-related "prior art products/patents" statement referencing this patent.

Bottom line: I found no litigation involving US 6,058,315, and I state that as a no-litigation-known finding rather than a certified negative. To convert this into a definitive answer I would recommend: (a) a PACER/Docket Alarm assignee-and-patent search for "6:058,315" across all districts, filtering out the unrelated "6058315" hits; (b) a Unified Patents portal litigation and PTAB search on the patent number; and (c) a CAFC docket search (the court's online docket is free) for "6,058,315." I can run those specific follow-ups if you want them pursued.

I'll start by verifying the structured block's default against live sources before treating "no PTAB activity" as final.

Let me run a few more targeted checks on litigation/assertion history and any PTAB docket entries.

Let me do a final confirmation sweep on Unified Patents/defensive aggregators and the patent's expired status.

Proceedings overview

Total AIA trial proceedings on file for US 6,058,315: 0. The structured "PTAB proceedings on file" block — sourced from the USPTO Open Data Portal, the canonical source for this task — returns no IPR, PGR, or CBM proceedings, and my live web searches (Google Patents family/prosecution data, patent-family citation tables, and targeted queries for "6,058,315" + IPR201/PGR201/CBM201, plus litigation/assertion queries) surfaced none either. There is therefore no breakdown to give: no active proceedings, no invalidated claims, no sustained claims, no settlements, no institution denials. (Caveat: my final two confirmation sweeps — for Unified Patents/RPX involvement and for expiration/maintenance-fee history — were cut off by a tool-call limit; see "Recommended next steps.")

The bottom line for a defendant is unusual and, if anything, stronger than an IPR win: no one has ever needed to IPR this patent, because it is expired. Per the structured data, the patent's anticipated expiration was 2016-03-13 and its current legal status is "Expired - Lifetime." A demand letter citing US 6,058,315 today cannot be backed by an infringement theory for current making, use, sale, or importation — the exclusive right ended over a decade ago. The absence of PTAB activity here is not "the patent is hardened"; it is "the patent is dead."

(no proceedings to report)

There are no PTAB proceeding numbers, petitioner/patent-owner captions, panels, institution decisions, Final Written Decisions, terminations, or CAFC appeals to summarize. I will not invent any. For transparency, here is what I verified instead:

• Patent identity (from the authoritative full text): US 6,058,315 A, application US 08/614,748, "Speaker assembly for a radiotelephone," inventor Joel A. Clark, filed 1996-03-13, granted 2000-05-02. Source: https://patents.google.com/patent/US6058315/en
• Assignment chain: Motorola, Inc. (1996-03-13) → Motorola Mobility, Inc. (2010) → Motorola Mobility LLC (2012) → Google Technology Holdings LLC (effective 2014-10-28) — the current assignee of record.
• Claims: 11 total; independent claims 1 and 8, with dependents 2–7 and 9–11.
• Foreign family (all co-priority 1996-03-13): GB 2311187 B, FR 2746241 A1, CN 1166767 A. No foreign counterpart revocation is reported in the provided data.
• No ex parte reexamination or reissue appears in the structured prosecution/legal-events data either (the legal-events history shows only assignments and maintenance-fee payments). I flag this as "not reported," not as a confirmed negative beyond the supplied data.

Strategic summary

Claim status: all 11 claims are UNTESTED at the PTAB and none are canceled. Claims 1–11 were never subjected to an AIA trial, so there is no institution decision, no FWD, and no claim-level invalidity holding to cite. Crucially, this is not a "hardened patent" story — the reason no challenger ever filed is almost certainly economic, not evidentiary. The patent expired 2016-03-13 ("Expired - Lifetime" per the structured data), which means the affirmative right to exclude is gone.

Estoppel landscape. Because no IPR/PGR/CBM ever reached a Final Written Decision, § 315(e)(2) estoppel does not exist against anyone — there is no petitioner, no privy, and no ground that was "raised or reasonably could have been raised." On paper, that leaves the entire prior-art universe unencumbered. In practice, the more decisive bars are statutory and temporal: (1) an IPR petition filed now would face the § 315(b) one-year bar for any party served with an infringement complaint more than a year earlier; and (2) more fundamentally, the § 286 six-year damages lookback reaches only back to 2020-09-30 as of today, a window entirely after the 2016-03-13 expiration — so an infringement suit filed now cannot capture damages from the patent's live term. PGR is doubly unavailable (the nine-month window after the 2000-05-02 grant closed decades ago, and this patent's effective filing date predates the AIA's 2013-03-16 PGR cutoff). CBM was never a fit (this is a mechanical/acoustic hardware patent, not a "covered business method" patent) and the transitional program sunset on 2020-09-14 in any event. IPR was the only AIA vehicle ever available here, and no one filed one.

Pattern signals. None of the usual markers are present. There is no repeat petitioner, because there is no petitioner at all. There is no patent-owner PTAB appeal history, because there is no adverse FWD to appeal. There is no defensive aggregator (Unified Patents, RPX, etc.) in the chain visible in the supplied data — though note my last confirmation search on that specific point was truncated, so treat it as unverified rather than affirmatively disproven. The provided data does list 18 "Cited By" references (e.g., US 6,321,070; US 6,473,625; US 6,526,150) and 44 family-citing documents, and the "Similar Documents" list contains GB 2311187 A ("Radiotelephone with an air gap provided between the speaker and sound ports") — the UK sibling of this very patent. These are citation relationships, not validity challenges, and should not be misread as adversarial activity.

Recommended next steps

• If you are a defendant and a demand letter cites US 6,058,315: the first and dispositive response is expiration. Per the structured data, the patent expired 2016-03-13 and carries the status "Expired - Lifetime." There is no FWD to link to (none exists), so the citation you want is the Google Patents front page showing "Anticipated expiration 2016-03-13" and "Expired - Lifetime": https://patents.google.com/patent/US6058315/en. Confirm the maintenance-fee and expiration record directly on USPTO Patent Center (linked from that page) and on PTAB E2E before relying on it in a demand response, since my verification sweep on maintenance-fee history was cut short.
• No active proceedings exist, so there are no institution deadlines, no oral-hearing dates, and no PTAB statutory 1-year FWD clocks to track. Nothing is pending.
• If you nonetheless want a PTAB-side record: an IPR on an expired patent is not categorically barred, but it would be an expensive way to confirm what the expiration date already establishes, and § 315(b)/§ 286 timing would likely moot it. Counsel should weigh whether a district-court invalidity counterclaim or a simple expiration/laches argument is the better posture — usually it will be, given the term is over.
• Preserve the caveats. To the best of the ODP-structured data and my searches, there is zero PTAB activity on file. If a recently-filed petition has not yet been indexed by ODP, it would not appear here; re-run PTAB E2E (https://ptab.uspto.gov) and the USPTO PTAB Decisions portal (https://www.uspto.gov/patents/ptab/decisions) before finalizing any opinion, and check CourtListener (https://www.courtlistener.com) for any Federal Circuit appeal naming the '315 patent. I found none.

I'll pull what I can from live sources to fill in the recording-side details (correspondents, reel/frame confirmations) that the Google Patents snapshot doesn't expose.

Good — the chain and the entity addresses are confirming. Now let me check for correspondent-of-record details and any assertion history on this patent.

Assignment & Ownership Reconstruction — US 6,058,315

Patent: US 6,058,315 A ("Speaker assembly for a radiotelephone")
Application: 08/614,748 · filed 1996‑03‑13 · issued 2000‑05‑02 · term expired 2016‑03‑13 ("Expired – Lifetime")
Family: FR2746241A1 · GB2311187B (granted 2000‑09‑13) · CN1166767A
Records located: yes — four recorded events. The Assignment Center does have records for this patent; the chain below is reconstructed from the Google Patents legal‑events table (which carries reel/frame), corroborated against EPO INPADOC and the UK IPO register.

Inventors

Pattern notes. A single inventor who assigned to the company on the same day as filing is the textbook employee‑invention‑assignment profile; there is no unusual pattern here.

• No evidence of inventor departure within 12 months of filing. The assignment executed 1996‑03‑13 removes any question of an inventor retaining rights that could later be re‑sold, but I could not verify Clark's employment end‑date — nothing in the Assignment Center, PEDS/ODP, or Indexed INPADOC data identifies a second, inventor‑side transfer. Treat "no inventor‑side post‑filing transfer" as a positive finding; treat "inventor stayed N years" as not determined.
• Do not read the 2010 spin‑off as an inventor event. It was a corporate transfer, not an inventor‑side one.

Original assignee

Motorola, Inc. (Illinois corporation; principal IP address of record 1303 East Algonquin Road, Schaumburg, IL 60196 — confirmed on the UK register for sibling Motorola filings).

• Primary line of business: wireless communications and semiconductors; at the 1996 filing date, one of the two dominant global handheld‑radiotelephone manufacturers.
• Product embodying the claims: Yes. The specification is written around a shipping product architecture — a foldable handheld radiotelephone (FIGS. 1–2) with a low‑acoustic‑impedance dynamic speaker, and it names commercial parts (Hosiden model HDR 0970; "Primo brand CR9" piezo) and reports measured dB improvements. This is an operating‑company engineering patent, not a paper patent.
• Current status of the original assignee: Defunct as an entity. Motorola, Inc. was split in 2011 into Motorola Solutions, Inc. (enterprise/public‑safety) and Motorola Mobility, Inc. (mobile devices). The patent‑relevant successor here is Motorola Mobility, whose mobile‑phone business was acquired by Google in 2012 and then sold to Lenovo (Google's own 8‑K recites: "after splitting into companies, saw its mobile phone business acquired by Google in 2012. Google then sold the business to Lenovo two years later"). No bankruptcy, no Chapter 7/11.

Assignment timeline

Field‑level caveat before the table: the correspondent of record is not exposed in the Google Patents legal‑events table, in EPO INPADOC, or in the UK IPO register — those sources surface only conveyance, parties, execution date, recording date, and reel/frame. I attempted to retrieve the Assignment Center detail pages in this session and could not. The correspondent field is therefore recorded below as "not retrieved," not as "none." This is the single largest gap in this reconstruction and it is precisely the field your brief flags as most probative; it should be pulled manually at assignment.uspto.gov / assignmentcenter.uspto.gov before this analysis is relied on.

1. 1996‑03‑13 (executed) / recorded 1996‑03‑13 — Reel 007877/0672

• Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST"
• Assignor: Joel A. Clark
• Assignee: Motorola, Inc. (Illinois)
• Correspondent: not retrieved (INPADOC/Google surface no correspondent; expected to be Motorola in‑house IP department, Schaumburg IL — inference only, not a finding)
• Context: Standard employee‑invention assignment, executed the same day as filing.

2. 2010‑07‑31 (executed) / recorded 2010‑12‑13 — Reel 025673/0558

• Conveyance: Assignment — "ASSIGNMENT OF ASSIGNOR'S INTEREST"
• Assignor: Motorola, Inc.
• Assignee: Motorola Mobility, Inc., 600 North US Highway 45, Libertyville, IL 60048
• Correspondent: not retrieved
• Context: Internal corporate separation — blanket portfolio conveyance into the spun‑off mobile‑devices entity. Note the ~4.5‑month execute‑to‑record lag. This reel is a portfolio‑level blanket recording: the identical reel 025673/0558 appears against unrelated Motorola patents (e.g., US 6,233,231; US 6,091,757) in INPADOC, so it is not patent‑specific. The same reel/date/effective‑date triple is independently confirmed on the UK register ("deed of assignment dated 31.07.2010"). No repeat‑correspondent inference can be drawn without the correspondent fields.

3. 2012‑06‑22 (executed) / recorded 2012‑10‑02 — Reel 029216/0282

• Conveyance: Change of Name — "CHANGE OF NAME"
• Assignor: Motorola Mobility, Inc.
• Assignee: Motorola Mobility LLC, 600 North US Highway 45, Libertyville, IL 60048
• Correspondent: not retrieved
• Context: Change of name only — no transfer of title; entity conversion into an LLC after Google's acquisition of Motorola Mobility. Same entity, same address; independently corroborated on the UK register ("Notification of change of Applicant/Proprietor name … to MOTOROLA MOBILITY LLC … dated 22.06.2012").

4. 2014‑10‑28 (executed) / recorded 2014‑11‑20 — Reel 034303/0001

• Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST"
• Assignor: Motorola Mobility LLC
• Assignee: Google Technology Holdings LLC, 1600 Amphitheatre Parkway, Mountain View, CA 94043
• Correspondent: not retrieved. Contextual datum, different record — do not conflate: on a 2016 trademark assignment (reel 5725/0284, EXO LEVEL LLC → Google Inc.), the correspondent of record was GAVIN CHARLSTON, 1600 Amphitheatre Parkway, Mountain View, CA — i.e., Google's recordings have been handled by in‑house personnel rather than an outside NPE‑style filing firm. That is a one‑off observation from another dossier, not evidence about reel 034303/0001.
• Context: Internal portfolio reorganisation / carve‑out — Google retained the vast majority of the Motorola Mobility patent portfolio and placed it in its captive IP‑holding subsidiary coincident with the Lenovo handset‑business sale (Acquisition Agreement 2014‑01‑29; closing 2014‑10‑30). Google's 8‑K states Google "will retain the vast majority of the Business's patent portfolio, which will be licensed back to the Business." The same deed of 28.10.2014 is recorded against Motorola/Google patents at the UK IPO.

Maintenance‑fee events (not assignments, listed only for term completeness): 2003‑09‑26 (4 yr), 2007‑09‑14 (8 yr), 2011‑09‑23 (12 yr). Three FPAY payments is the complete set for a 20‑year post‑1995‑URAA term; the patent therefore ran to its full term and expired 2016‑03‑13 without lapse.

No assignment is recorded after 2014‑11‑20. The chain terminates at Google Technology Holdings LLC.

Timeline diagram

timeline
    title Ownership of US 6058315
    1996 : Filed by inventor Joel A Clark
         : Assigned to Motorola Inc reel 007877 frame 0672
    2000 : Patent issued
    2010 : Motorola to Motorola Mobility reel 025673 frame 0558
    2012 : Name change to Motorola Mobility LLC reel 029216 frame 0282
    2014 : Portfolio to Google Technology Holdings reel 034303 frame 0001
    2016 : Patent term expires

NPE / troll-pattern signals

1. Shell‑entity transfer — NOT PRESENT. Every assignee in the chain is a large operating enterprise or a wholly owned subsidiary of one: Motorola, Inc. (reel 007877/0672) → Motorola Mobility, Inc. (025673/0558) → Motorola Mobility LLC (029216/0282) → Google Technology Holdings LLC (034303/0001). The terminal assignee carries a "Holdings" suffix, but the two other shell tells are absent: its recorded address is Google's operating HQ (1600 Amphitheatre Parkway, Mountain View CA 94043), not a registered‑agent service, and its assignor is its own corporate parent rather than an arm's‑length seller. A suffix alone is not a finding.

2. Known asserter in the chain — NOT PRESENT. None of Motorola, Inc., Motorola Mobility, Inc./LLC, or Google Technology Holdings LLC appears on the listed NPE rosters (Acacia, Marathon, IV, IPNav, Wi‑LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, DGC, Spangenberg entities). Caveat: I could not complete a live RPX/Unified Patents asserter‑directory check in this session; this call rests on the absence of the names from those canonical lists.

3. Repeat correspondent across the chain — UNCLEAR (data gap, not a negative). Zero correspondent fields were retrievable for reels 007877/0672, 025673/0558, 029216/0282, or 034303/0001 from the sources that were reachable. Because the signal is recurrence, an empty field set cannot falsify it. This is the one signal that must be re‑run manually.

4. Cascading transfers — NOT PRESENT. Four recorded events span 18 years, and one of them (029216/0282) conveys no title at all — it is a change of name. The remaining three transfers track documented corporate events (2010 spin‑off, 2012 LLC conversion, 2014 Lenovo carve‑out), all within a single corporate family, with no unrelated assignees, no common‑principal strangers, and no sub‑24‑month LLC hop chain. Nothing here resembles an engineered title‑laundering sequence.

5. Pre‑litigation transfer — NOT PRESENT. No infringement action naming US 6,058,315 surfaced, and the 2014‑10‑28 transfer preceded the patent's 2016‑03‑13 expiry by only ~17 months — too short a runway for an assertion campaign, and no suit is recorded. The 2014 recording is explained on its face by the Lenovo transaction rather than by a litigation docket.

6. Bankruptcy fire‑sale — NOT PRESENT. Motorola's mobile business moved by spin‑off and acquisition (Google, 2012), not by insolvency; Google's 8‑K describes a negotiated $2.91B sale of the handset business to Lenovo. No Chapter 7/11 docket is implicated. The only fee‑related fact is that the patent's three maintenance fees were all timely paid.

7. Privateering — NOT PRESENT (inverse fact present). Privateering would be Motorola handing the portfolio to an NPE to sue competitors. The record shows the opposite: the portfolio went up to Google's captive holding company and was licensed back to Lenovo for continued operations (8‑K, 2014‑01‑29). The patent stayed inside an operating‑company structure.

8. Defensive aggregator (anti‑NPE) — NOT PRESENT as a recorded assignment. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN; reel 034303/0001 ends at Google Technology Holdings LLC. (Google is a LOT Network founder, but LOT membership is not a recorded assignment and does not appear in this patent's chain — not a finding.)

Verdict

Defensive / non‑asserting.

Every recorded link is an operating‑company or captive‑IP‑subsidiary transfer: reel 007877/0672 (Motorola, 1996‑03‑13), reel 025673/0558 (2010 spin‑off), reel 029216/0282 (2012 change of name only), reel 034303/0001 (Google's captive holding company, executed 2014‑10‑28 and explained on its face by the Lenovo carve‑out, with the portfolio licensed back to Lenovo per Google's 8‑K). Not one of the eight NPE signals is present — none of the six non‑correspondent signals could be satisfied, and the seventh (repeat correspondent) is simply unretrievable rather than positive. The patent also expired 2016‑03‑13 with all maintenance fees paid and no assertion on record, so the asset is now neutralised by law as well as by ownership.

Two honest qualifications: (a) this is not a canonical aggregator termination — the terminal entity is a captive operating‑company IP holder, not RPX/AST/LOT/Unified, so the label is being applied on substance ("no assertion, no NPE markers, full‑term expiry") rather than on the strict aggregator definition; and (b) because no correspondent of record was retrievable for any of the four reels, signal 3 remains unchecked, and if the correspondent on reels 025673/0558 / 029216/0282 / 034303/0001 were shown to recur across unrelated NPE dossiers, this verdict would need revisiting. On the evidence actually of record, the chain is a clean 18‑year corporate succession with no NPE characteristics.

Verify at: USPTO Assignment Search — US 6,058,315 · USPTO Assignment Center · Google Patents legal events · EPO INPADOC legal status · UK IPO register, sibling Motorola/Google filings (addresses + deed dates) · Google 8‑K dated 2014‑01‑29 (Lenovo/Motorola patent retention)

Priority action item: re‑run the four reel/frame entries above at the Assignment Center and capture the correspondent name, firm, and address for each. Those four fields are the only materially missing data in this reconstruction, and they are the fields your brief identifies as the highest‑value tell.

I'll verify the cited references with targeted searches before building the anticipation analysis.

Let me verify several more of the cited references to ground the analysis accurately.

Scope note before the analysis

I confirmed the target against the authoritative full text supplied in this session: US 6,058,315 A, application US 08/614,748, "Speaker assembly for a radiotelephone," Joel A. Clark, Motorola, Inc., filed 1996‑03‑13, issued 2000‑05‑02. Per the operating rule, I have not auto‑corrected any identifier and have not folded in similar‑number hits (e.g., the unrelated CBP "SKU# 6058315" Christmas‑Cow ruling, or the various ~8‑digit docket strings) from the earlier litigation scan.

Two contradictions to flag explicitly:

1. The task states the current date as April 26, 2026, while the session context says 2026‑09‑30, and the prior (authoritative) litigation section references a CBP ruling dated 2026‑08‑04. These cannot all be the "current" date. Nothing in the §102 analysis below turns on which is correct, but the inconsistency is real and I am not resolving it by assumption.
2. The prior section lists the AKG Acoustics non‑patent citation twice ("Revision #3" and "Revision 3," both June 22, 1995, 5 pages). That is a duplicate of the same document, not two references — noted so it isn't double‑counted as two prior‑art items.

Legal framework (pre‑AIA §102, because the 1996 filing predates the AIA)

Because the application was filed 1996‑03‑13, pre‑AIA 35 U.S.C. §102 governs. The operative dates:

• §102(b) critical date = 1995‑03‑13 (one year before filing). Anything patented or described in a printed publication before this date is statutory bar art.
• §102(a): known/used by others, or patented/published, before the applicant's invention date (not of record here; the filing date is the only date we can rely on).
• §102(e): a U.S. patent granted on an application filed before 1996‑03‑13 is prior art as of that earlier filing date.
• Anticipation requires a single reference disclosing every limitation arranged as in the claim. For a combination claim like claim 1 or claim 8, single‑reference anticipation is unusual; most of these references are §103 (obviousness) / background art, not anticipatory. I flag that per item rather than overstating.

Master table — the 20 of‑record patent citations (plus 1 NPL item)

Date source: the authoritative citation table in the supplied patent record (Espacenet's cited‑documents page independently confirms the ordering/numbering of items 2 and 3).

Per‑reference detail and claim mapping

The acoustically "closest" references (still not anticipatory of claims 1 or 8)

US 5,168,527 A — LZR Electronics, Miniature speaker variable standoff mount (filed 1990‑06‑14; pub. 1992‑12‑01; §102(b)).
Discloses a miniature loudspeaker on a frame with mounting prongs having step changes in cross‑section that hold the speaker "an adjustable distance from the surface," with the frame/prongs as one unified structure. Verified from the patent text and its own claims: independent claim 11 recites "at least one stand off mounting prong … having a plurality of step changes in cross‑section … alternately usable … to selectively support said speaker at a plurality of desired distances."

• Maps to: the standoff limitation of claim 1 ("at least one standoff having portions of different heights") and the standoff/spacing limitation of claim 8 — this is the single best of‑record read on "portions of different heights."
• Anticipation? No. It mounts to a printed circuit board, not a "front upper housing portion having a front surface and a rear surface" with "first and second porting areas"; there is no rear housing portion forming an acoustic enclosure, and no air‑gap‑to‑enclosure leak recited. It supports a §103 rationale for the standoff element only.

US 5,369,701 A — AT&T, Compact loudspeaker assembly (filed 1992‑10‑28; pub. 1994‑11‑29; §102(b)).
Discloses an upper housing member 400 with sound apertures 421, a loudspeaker 300 mounted beneath the apertures and firing through them, a "sealed enclosure 420 … that completely surrounds loudspeaker 300," and a tuned port 422 tuned to ~286 Hz to extend low‑frequency cutoff.

• Maps to: the front‑housing‑with‑ports + rear‑housing‑enclosure + speaker‑facing‑ports elements of claims 1 and 8.
• Anticipation? No — and it points the other way. The enclosure is expressly sealed, the speaker covers the apertures (no standoff, no air gap), and the port is a bass‑reflex tuning port rather than a "second porting area" open beyond the speaker footprint for leakage. It is background/§103 art and arguably teaches away from a deliberate acoustic leak.

US 4,727,583 A — Motorola, Telephone transducer with improved frequency response (filed 1986‑10‑28; pub. 1988‑02‑23; §102(b)).
Discloses a small transducer in a very thin enclosure with an "inverted" cone spaced from the retainer, a small trapped‑air volume behind the cone, apertures 22 essentially blocked by the housing wall, and pre‑emphasis/equalization to flatten response. It discusses the difficulty of flat response in small telephone/radio enclosures.

• Maps to: the low‑acoustic‑impedance speaker and the signal‑preconditioning concepts underlying claims 2 and 3 (though its circuit is pre‑emphasis, not a 2‑pole low‑pass), and the general spacing/enclosure elements of claims 1/8.
• Anticipation? No. No dual porting areas, no standoffs, no leakage passage; and it blocks the rear apertures rather than leaking.

US 4,029,170 A — B & P Enterprises, Radial sound port speaker (filed 1974‑09‑06; pub. 1977‑06‑14; §102(b)).
Discloses a speaker structure with sound ports 18, 19, a baffle/partition 3, and sound waves that flow around the edges of the partition into resonance chambers; ribs channel air movement.

• Maps to: the "passage for air to leak … into the enclosure" and "ports beyond the perimeter" concepts of claims 1 and 8.
• Anticipation? No. It is a large, wall‑hanging hi‑fi enclosure with sealed chambers; nothing about a radiotelephone housing, standoffs, or two porting areas relative to a floating earpiece speaker.

Ported‑enclosure / bass‑reflex art (background for the port and enclosure elements)

US 3,952,159 A — Zenith, Ducted port reflex enclosure (filed 1973‑03‑09; pub. 1976‑04‑20; §102(b)). Classic ducted‑port reflex loading; cited for the port/acoustic‑mass principle underlying the enclosure/port limitations of claims 1 and 8. No radiotelephone, standoff, or uncovered second porting area → no anticipation; general §103 background.

US 4,440,260 A — Jamo Hi‑Fi, Bass‑reflex loudspeaker system (filed 1981‑02‑03; pub. 1984‑04‑03; §102(b)). Bass‑reflex port/enclosure art; same limited relevance as Zenith → background only.

US 4,128,738 A — Gallery, Compact transmission line loudspeaker system (filed 1976‑09‑28; pub. 1978‑12‑05; §102(b)). Transmission‑line acoustic loading; background for enclosure loading → no anticipation.

US 4,437,539 A — Festa, Speaker enclosure (filed 1982‑09‑30; pub. 1984‑03‑20; §102(b)). General speaker‑enclosure structure → no anticipation.

US 5,194,701 A — N.P.L. Ltd., Speaker structure (filed 1991‑09‑11; pub. 1993‑03‑16; §102(b)). General speaker‑structure/mounting art → no anticipation.

US 4,142,604 A — Smith, Speaker structure (filed 1976‑09‑15; pub. 1979‑03‑06; §102(b)). Speaker‑structure background → no anticipation.

Telephony / handset transducer and sealing art

US 4,163,875 A — Northern Telecom, Telephone handset with transmitter having a one piece gasket for sealing and holding of transmitter members (filed 1978‑02‑09; pub. 1979‑08‑07; §102(b)). Teaches a sealing gasket that both seals and holds a telephone transducer. Relevant as evidence that the art sought airtight coupling — i.e., it teaches away from the deliberate air gap/acoustic leak of claims 1 and 8. No anticipation.

EP 0 364 935 A1 — Kirk Acoustics, Telephone transducer (filed 1988‑10‑21; pub. 1990‑04‑25; §102(b)). Telephony transducer background → no anticipation.

GB 1,295,363 A (1970‑07‑28 / pub. 1972‑11‑08; §102(b)). Earliest of‑record item; telephone‑transducer background → no anticipation.

US 5,327,507 A — Sharp, Headphone apparatus (filed 1990‑04‑10; pub. 1994‑07‑05; §102(b)). Ear‑coupled transducer background → no anticipation.

US 5,394,467 A — Claircom, Multi‑purpose telephone strain relief (filed 1993‑03‑26; pub. 1995‑02‑28; §102(b)). Telephone housing/strain‑relief hardware → tangential, no anticipation.

Filter / speaker‑support art (relevant to dependent claims 2–7)

US 5,153,915 A — Creative Acoustics, Speaker filtering circuit and support therefor (filed 1990‑05‑18; pub. 1992‑10‑06; §102(b)). Combines a speaker filtering circuit with a speaker support/mounting structure.

• Maps to: the "low‑pass electric filter, coupled with the speaker" of claim 2 (and, less directly, the complex 2‑pole filter of claim 3) and, in a general sense, the support/mounting theme of claims 4–7/10–11.
• Anticipation? No. It is cited as the filtering‑plus‑support concept; it does not disclose the radiotelephone porting/standoff/leak combination. Its real value is as a §103 building block against the filter‑dependent claims. (I was unable to retrieve and verify its full claim text in this session — treat this as the description, not a verbatim reproduction.)

Radiotelephone form‑factor / antenna / design art

US 5,668,867 A — NEC, Foldable portable telephone with improved antenna gain (filed 1993‑12‑28; pub. 1997‑09‑16; §102(e) — filing predates 1996‑03‑13). Foldable portable‑telephone housing with antenna improvements.

• Maps to: only the "radiotelephone" preamble and the foldable‑handset context of claims 1/8 (the specification's FIG. 1–2 foldable phone).
• Anticipation? No — silent on speaker mounting, ports, standoffs, leak.

US 5,014,346 A — Motorola, Rotatable contactless antenna coupler and antenna (filed 1988‑01‑04; pub. 1991‑05‑07; §102(b)). Antenna coupling only → no anticipation; tangential to the preamble.

US 5,068,917 A — Matsushita, Portable radio transceiver (filed 1987‑11‑20; pub. 1991‑11‑26; §102(b)). Portable‑radio housing background → no anticipation.

US D385,873 S — Motorola, Housing for a portable telephone (filed 1995‑05‑09; pub. 1997‑11‑04; §102(e)). Ornamental design of a portable‑telephone housing → no anticipation of any claim; design patents carry no functional disclosure of the standoff/port/air‑gap combination.

Non‑patent citation

E. Kerschbaum, AKG Acoustics, Dynamic Transducer IXMR specification, Revision #3, June 22, 1995, 5 pages (cited twice — same document). A vendor specification for a dynamic transducer, i.e., a printed publication dated 1995‑06‑22. Because that date is after the §102(b) critical date (1995‑03‑13), it is available only as §102(a) art (as of its date vs. the applicant's invention date).

• Maps to: the specification's "low‑acoustic‑impedance dynamic speaker" element (the Hosiden HDR 0970‑type driver) of claims 1 and 8.
• Anticipation? No. A transducer datasheet discloses a driver, not a radiotelephone housing with first/second porting areas, standoffs, and a leak passage.

Secondary set — citations appearing in the foreign family (NOT of record in the U.S. case)

For completeness (and clearly separated, because these are not U.S. of‑record citations to US 6,058,315): the "Family Cites Families" list corresponds to art cited during prosecution of the FR/GB/CN counterparts. These post‑date or merely parallel the U.S. case for §102 purposes only if their dates qualify; the notable ones are US 5,201,069 A — Motorola, Electroacoustic transducer mounting apparatus (filed 1991‑10‑18, pub. 1993‑04‑06; §102(b) — transducer mounting, potentially relevant to the standoff/mount element) and US 5,402,486 A — Wang, Earring compatible telephone handset receiver (filed 1993‑12‑29, pub. 1995‑03‑28). The others (DE 3112221, JP S60‑142699, JP S61‑123388, DE 3727917, JP H05‑218940, JP H07‑177051, US 5,414,444) are foreign/other background. I flag these only so the record is complete; they are not the "patent citations for 6058315" the task asks about.

Also note: the "Families Citing this family" items (FI 115108 B — Nokia, improving earphone leakage resistance; US 6,064,894 A — Motorola; DE 19841061 A1 — Bosch; DK 173789 B1 / DK 176255 B1 — Kirk/Sonion) are later filings that cite the '315 family — they are not prior art to US 6,058,315.

Bottom line

• No single of‑record reference anticipates claims 1 or 8. Every one of the 20 patent citations and the one NPL item is missing at least the core combination — (a) a front upper housing with two distinct porting areas on its rear surface, (b) standoffs ("portions of different heights") positioning a speaker over the first area, (c) an air gap plus a leak passage into an enclosure, and (d) a second porting area not covered by the speaker.
• Closest single‑reference reads, element‑by‑element:
  • US 5,168,527 (LZR) → the standoff element of claims 1/8 (stepped prongs holding a speaker at a selectable distance) — strongest §102 read on any single element.
  • US 5,369,701 (AT&T) → the housed‑speaker‑behind‑housing‑ports + enclosure + port elements of claims 1/8, but it is sealed and therefore cuts against the leak feature.
  • US 4,727,583 (Motorola) → spacing/air‑load and signal preconditioning themes of claims 2/3.
  • US 5,153,915 (Creative Acoustics) → the filter‑plus‑support concept of claims 2/3.
  • US 4,029,170 (B&P) → flow around a partition into a chamber (leak/passage theme), in a non‑telephony context.
• These are §103 references, not §102 anticipations. Any rejection on this record would rest on obviousness (e.g., LZR's stepped standoff + AT&T's ported/speaker‑housing arrangement + a leakage/bass‑balance rationale), not single‑reference anticipation. The Motorola‑to‑Motorola and sealing references (US 4,727,583; US 4,163,875) specifically teach away from the deliberate air gap.

Caveats on confidence:

• I read every reference's date/number/assignee/title from the authoritative citation table in the supplied record; I verified the substance of US 5,168,527, US 5,369,701, US 4,727,583, and US 4,029,170 against their own text via web search. I did not independently re‑verify the full text of US 4,128,738, US 4,142,604, US 4,437,539, US 4,440,260, US 4,163,875, GB 1,295,363, EP 0 364 935, US 5,014,346, US 5,068,917, US 5,153,915, US 5,194,701, US 5,327,507, US 5,394,467, US 5,668,867, or US D385,873 — for those, my characterizations come from the citation metadata and titles, and should be treated as screening‑level, not verified element‑by‑element.
• "Potentially anticipates" above means maps to a recited limitation / is close enough to warrant an anticipation‑vs‑§103 inquiry; it is not a legal conclusion that the claim is anticipated.
• I could not retrieve the full claim text of US 5,153,915 or EP 0 364 935 in this session; the descriptions for those are inferred from the record's metadata and should be confirmed against the documents themselves.

I'll ground this on the cited-art record. Since the prior-art list gives me titles but not full texts, let me verify subject matter for the structurally critical references before mapping.

Obviousness Analysis — US 6,058,315 Under 35 U.S.C. § 103

Building on the prior sections (bibliography, claims, litigation). This section does not repeat the bibliographic table; it assumes it.

0. Contradiction flags (per operating rule)

Two discrepancies I am obligated to surface before analyzing:

1. Reference number error in the earlier "Prosecution context" paragraph. That section lists "US 4,427,583 (Motorola)" among the cited art. The record actually lists US 4,727,583 A — Motorola, "Telephone transducer with improved frequency response" (1986-10-28 / 1988-02-23). US 4,427,583 does not appear anywhere in the "Citations (20)" table. I treat this as a transcription slip in the earlier section and use 4,727,583 below. This matters materially, because as shown in §4 that reference is the single most on-point item of record, and 4,427,583 (a 1984 Jamo/Gallery-era loudspeaker reference) is not.
2. Date inconsistency carried in from the earlier sections. The litigation section cites a CBP ruling dated 2026-08-04, while this task header sets the current date at 2026-04-26. A document cannot post-date "today." One of the two dates is wrong; I flag it rather than silently reconcile it. Likewise the fetched record self-reports both "Cited By (18)" and "Cited By (44)" — a display artifact, not substantive.

1. Governing standard

• Pre-AIA § 103(a) governs. The application was filed 1996-03-13, before the AIA's 2013-03-16 first-inventor-to-file cutoff. There is no separate "prior art" definition to parse under § 102(a)(1)/(2).
• Graham v. John Deere factors: scope/content of the art; differences from the claims; level of ordinary skill; objective evidence.
• KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007): a combination is obvious where the elements were known and the combination does no more than yield predictable results; "the combination of familiar elements according to known methods is likely obvious when it does no more than yield predictable results." Also relevant here: design incentives and market forces, and the principle that a recited parameter that the specification itself treats as a routine design choice is not a source of patentable weight.
• MPEP § 2143 rationales available on this record: (A) known elements combined per known methods → predictable result; (B) simple substitution of one known element for another; (C) known technique used to improve a similar device in the same way; (D) applying a known technique to a known device ready for improvement; (F) design incentives/market forces; (G) teachings in the references themselves supplying the motivation.
• Combined teachings, not bodily incorporation. In re Keller; In re Merck. The inquiry is what the references, taken together, would have suggested — a reference is available for everything it teaches, including in its background.
• Analogous art. The relevant field is telephone/portable-radio electroacoustics (transducer + earpiece housing + drive electronics). Loudspeaker-enclosure art is reasonably pertinent to the "tune a tiny enclosure's frequency response" problem — and, decisively, the '315 specification itself reasons from loudspeaker principles ("the size of the enclosure affects the frequency response of the speaker"), which is an admission that this art is pertinent.

2. Level of ordinary skill (c. 1996)

A POSITA would be a person with a bachelor's degree in electrical engineering, mechanical engineering, applied physics, or acoustics and roughly 2–5 years designing miniature electroacoustic transducers and enclosures for portable communication devices (cordless handsets, cellular radiotelephones, pagers); familiar with diaphragm loading, acoustic resistance/leakage, enclosure volume effects on resonance/frequency response, and elementary passive/active filter design.

This level is effectively conceded by the patent. The specification states: "The technique for selecting the appropriate air-gap for a certain enclosure and speaker is readily understood by one of ordinary skill in the art." That sentence hands a challenger the argument that the gap dimension — the claimed "predetermined distance" — is routine optimization.

3. The limitations that actually decide the case

Two features must be construed before mapping art:

Critically, independent claims 1 and 8 recite no frequency response, no acoustic impedance, no "low-acoustic impedance speaker," no absorber, and no filter. The "low-acoustic impedance speaker" appears only in the specification/abstract. Claims 1 and 8 are therefore pure structural claims and are correspondingly vulnerable.

4. Reference-by-reference mapping (verified text where available)

I retrieved full or substantial text for the five references that carry the analysis. For the remainder I have titles, dates and assignees only, and I mark the mapping as inference.

4.1 US 4,727,583 A — Motorola, "Telephone transducer with improved frequency response" (verified, Google Patents)

Same assignee as the patent under analysis; same problem statement.

Verified disclosures:

• A housing 10 with a plastic "speaker retainer 14 or 'ear cup'" whose top surface "may be contoured to accommodate the ear of the user"; "Small sound apertures 16 lead through the center surface of the retainer 14 to an interior cavity 18 which contains a speaker enclosure 20."
• "The 'front' of the cone 28 is spaced away from the inner surface of the speaker retainer 14 just enough to allow freedom of motion for the cone." → a diaphragm-to-ported-surface air gap.
• "In telephones and telephone-type devices, the speaker is small with close coupling to the ear of the user… In the case of portable phones and radios, however, the speaker and speaker enclosure are likely to be much smaller and thinner, and telephone sound quality is very difficult to obtain." → identical problem statement.
• Its stated solution is a small sealed back volume to push resonance out of band, "The overall output response is then flattened out with appropriate pre-emphasis," with "FIG. 9 … a diagram of an audio apparatus employing the invention" → an electrical preconditioning/equalization stage in series with the transducer, i.e., the substance of claims 2/3.

It does not disclose standoffs, nor a second uncovered porting area (indeed its rear apertures 22 are deliberately blocked). It is nonetheless the strongest single item of record for the problem and for the air-gap + equalization combination.

4.2 US 5,168,527 A — LZR Electronics, "Miniature speaker variable standoff mount" (verified, Google Patents)

The reference that reads on claim 1's standoff limitation almost verbatim.

Verified disclosures:

• A miniature loudspeaker 4 on a frame having mounting "prongs 18"; the prong "is a stamped flat piece having a tip 20 which has a smaller cross-section than the cross-section of the prong in the area immediately adjacent … Thus, the speaker device has two step changes 26 and 28 along its length."
• "The two step changes 26 and 28 are alternately usable for engaging the mounting surface … holding the speaker device 2 in place yet maintaining a spacing between the speaker 4 and the printed circuit board."
• Independent claim 11: "at least one stand off mounting prong secured to said frame, said at least one prong having a plurality of step changes in cross-section located along its length … wherein said step changes are alternately usable … so as to selectively support said speaker at a plurality of desired distances from said mounting surface."

This is, in substance, "at least one standoff having portions of different heights" supporting a miniature speaker a preselected distance from a surface it faces. The only differences are the substrate (PC board vs. ported housing wall) and the stated motivation (component clearance and vibration isolation rather than acoustic leak) — neither of which is a structural difference. This reference was of record, which strongly suggests claim 1's "portions of different heights" wording was drafted with it in mind; that is an inference, not a proven prosecution fact.

4.3 EP 0 364 935 A1 — Kirk Acoustics A/S, "Telephone transducer" (verified, EPO PDF)

The closest art on the deliberate-leak concept, and it is telephone art, not hi-fi art.

Verified disclosures:

• "a telephone handset 1 which comprises a house 2 in which there is arranged a low impedance transducer 3. The transducer 3 is secured in a front cover 7 so that there from the front side of the transducer diaphragm 5 is a normal slot connection to holes or apertures 6 in the house 2."
• "there is established a pure acoustic ohmic connection 8 from the front side of the transducer diaphragm to the space 9 within the house 2, while maintaining a normal slot connection 10 from the front side of the diaphragm to the holes or apertures 6."
• "The apertures or slots 8, 14 are wholly or partly filled or covered with a sound absorbing material 15 such as cotton wool, foamed rubber or the like."
• Stated purpose: "By ensuring that this connection is a pure acoustic ohmic connection we have obtained that the lower frequency range will have low impedance without adding undesired resonances in the higher frequency range," producing "a more natural reproduction of the speech and sound than what is possible from a conventional telephone."
• The leak apertures may be in the cover's bottom surface 13 (parallel to the diaphragm) or in the side wall 12 (i.e., laterally), or both.

Mapping: front housing with ear ports (6) facing the diaphragm → first porting area; a second, distinct acoustic path from the diaphragm front into the interior housing space (8/14) → the claimed air gap/passage leaking into the enclosure; sound-absorbing material in that path (15) → claims 4/5/11; and a low-impedance transducer → the component the '315 spec calls for by name (Hosiden HDR 0970 class).

4.4 US 5,153,915 A — Creative Acoustics, "Speaker filtering circuit and support therefor" (verified in part, Google Patents)

Verified: the patent is directed to a filtering network for a speaker (RLC), mounted on the speaker, and its figures expressly compare "RELATIVE FREQUENCY RESPONSE OF 6.5 in. SPEAKER WITHOUT RLC FILTER" against "SPEAKER WITH RLC FILTER." It is crossover-context art (coaxial woofer/tweeter), but it squarely teaches using a passive filtering network on a speaker to shape that speaker's frequency response — the substance of claims 2/3/9.

4.5 US 4,029,170 A — B & P Enterprises, "Radial sound port speaker" (verified, Google Patents)

Verified: a speaker 7 mounted in a panel 8 within a frame; front wall with sound ports 18 and 19; a baffle/partition 3 behind the speaker; and, importantly, "it is preferable… that the baffle or partition 3 be less in area than that of the back wall 1 in order to permit the flow of sound waves around the baffle or partition 3 and into the bass resonance chamber 21," with rearward waves from the cone "proceed[ing] around the edges of the baffle or partition 3." Also: ribs 11 that "direct, channel and compress the air movement."

Mapping: a front port region over the diaphragm plus a separate path around the speaker's periphery into a rear chamber — the geometric idea of a second porting area outside the speaker footprint. (Note the counter-current: '170 wants its chambers sealed; it is not a leak-teaching reference. It is a geometry teaching.)

4.6 Remaining record references — mapped by title/classification only (inference; full text not verified)

5. Combinations and motivation

Combination I — EP '935 + US '527 (+ US '170) → claims 1 and 8

Motivation (KSR (A)/(C)/(G)): All three are in miniature electroacoustic transducer and telephone-housing art. '935 supplies the reason to leak acoustic energy from the diaphragm face into the handset cavity — flat/low-impedance low-frequency response without high-frequency resonance — which is exactly the benefit the '315 asserts. '527 supplies the mechanism by which a POSITA would hold a miniature speaker off a surface at a selectable distance, and the '315 specification concedes that the gap/seal interplay is routine once the geometry exists ("the technique for selecting the appropriate air-gap … is readily understood by one of ordinary skill"). '170 supplies the geometry of an acoustic path that lies outside the speaker's footprint. Nothing in the combination produces an unpredicted result; the claimed benefit is the predictable consequence of a known leak.

Combination II — US '583 + US '527 + EP '935 → claims 1 and 8

'583 supplies the identical problem statement in the identical product category (portable phones and radios, "much smaller and thinner" enclosures), the ear-cup-with-apertures structure, and a diaphragm spaced from the aperture-bearing surface. It leaves gaps only for (a) the standoff (→ '527) and (b) a second, uncovered porting area open to the enclosure (→ '170 or '935's ohmic connection). Because '583 is the same assignee's own art addressing the same problem, it supplies a particularly clean design-incentive motivation under KSR (F): Motorola itself was working the problem of thin-enclosure telephone transducer response in 1986–1988.

Combination III — I or II + US '915 (+ AKG NPL) → claims 2, 3, 9

'915 expressly discloses a filtering circuit for a speaker with with/without-filter response curves; '583 discloses pre-emphasis of the audio apparatus to flatten response; the AKG IXMR spec of record supplies free-field response data. A two-pole (second-order) low-pass is the canonical textbook network (Sallen-Key / MFB / passive RLC); the '315 recites only ordinary component values (18 kΩ, 0.033 µF, 18 kΩ, 1000 pF, 0.1 µF) and reports no unexpected result. MPEP 2143(A)/(B): familiar elements, known method, predictable result; the corner frequency and Q are routine optimization. These claims are very hard to defend.

Combination IV — I or II + EP '935 + enclosure-damping art (Jamo '260 / Festa '539 / Gallery '873) → claims 4, 5, 6, 7, 10, 11

'935 directly discloses sound-absorbing material (cotton wool, foamed rubber) filling/covering the leak apertures — claims 4, 5 and 11. Absorbing rear-radiating waves with fibrous fill inside an enclosure is notorious in transmission-line and bass-reflex art — claims 6, 7, 10. Separately, the '315 gives an independent, non-acoustic motivation for the front absorber (covering ports to keep dust out — a durability/market-force rationale under KSR (F)).

Combination V — US '170 + US '527 → claim 8's "plurality of standoffs surrounding the plurality of ports"

'527 shows a frame with an outer ring 16 and three mounting prongs distributed around the speaker; '170 shows a plurality of flow paths around the speaker perimeter. Arranging plural standoffs around a port cluster is a mechanical expedient, not an inventive step.

6. Claim-by-claim vulnerability

Least vulnerable limitation: claim 1's "standoff having portions of different heights." Even though US '527's claim 11 uses the words "stand off mounting prong" with "a plurality of step changes," a patentee could argue that (i) a prong is not a "standoff," (ii) the LZR prongs mount to a PCB, not to a ported acoustic wall, and (iii) the LZR spacing is for component clearance and vibration, not acoustics — so the reason to relocate that structure is where the § 103 case lives. I regard this as the patent's best (though not strong) redoubt, and it is precisely why the prosecution history should be pulled.

7. Anticipated counterarguments and responses

A. "The art teaches away — everything is specified for an airtight ear seal." The '315 background itself says both dominant speaker technologies are specified for airtight coupling, and US 4,163,875 shows gasket sealing. Response: (i) '935 affirmatively teaches the opposite for a telephone handset and states it produces better reproduction than a conventional telephone; (ii) US 5,402,486 (of record via the family citations) is a handset receiver expressly built to work with an earring — i.e., without a seal; (iii) the '315 background concedes the problem (≈15 dB loss at 300 Hz with a Primo CR9, and ≈11 dB response spread with an airtight-mounted Hosiden HDR 0970) and concedes an off-the-shelf low-acoustic-impedance speaker exists (Hosiden HDR 0970) — and '935 uses a "low impedance transducer." A preference elsewhere for seals does not "teach away" where a reference in the same field teaches the leak as desirable. In re Fulton; Medichem.

B. "Different fields — hi-fi loudspeakers vs. telephony." Response: the '315 specification reasons from loudspeaker enclosure physics and expressly invokes enclosure size as a response variable, so it cannot credibly call that art non-analogous; and '935 is squarely telephone art anyway.

C. "Improper hindsight / bodily incorporation." Response: the motivation is supplied by the references themselves — '935's stated low-frequency-impedance-without-high-frequency-resonance goal, '583's flat-response-with-thin-enclosure goal, and the '315's own background describing the leak-induced bass loss. That is the KSR (G) case, not hindsight. And In re Keller/Ratti defeat bodily-incorporation arguments.

D. Objective evidence. The record before me shows no commercial success with a proven nexus, no licensing/industry-praise evidence, and no long-felt-but-unsolved-need evidence beyond the background's generic assertion of a "need." The internal "3 dB improvement" measurements are design data, not Graham objective evidence. Absent a nexus, KSR's caution against over-weighting secondary considerations cuts in the challenger's favor.

E. Term/expiry. Any challenge window effectively closed with expiry on 2016-03-13; the realistic vehicles were a validity defense in a pre-2016 case or a reexamination, with IPR available only from 2012-09-16. (I note this as procedural context only and make no representation about any particular vehicle's availability for an expired patent.)

8. What would strengthen or defeat this analysis

To convert the above into paragraph-level claim charts, I would pull the full texts of: US 3,952,159; US 4,122,873; US 4,142,604; US 4,437,539; US 4,440,260; US 5,194,701; US 5,369,701; US 5,207,069; US 5,402,486; US 4,163,875; US 5,068,917; US 5,668,867. The three that could most change the picture are US 5,207,069 (Motorola transducer mounting apparatus — could be a § 102/§ 103 hit on the standoff + mount combination), US 5,402,486 (non-airtight telephony receiver — the strongest teaching-away rebuttal), and US 3,952,159 (ducted-port tuning).

The single highest-value non-obviousness datum would be the '315 file wrapper: if the examiner's reasons for allowance rest on the "second porting area not covered by the speaker" or on "standoff having portions of different heights," that tells a challenger exactly which limitation to attack with '935/'170 and '527 respectively. I have not reviewed the prosecution history and make no assertion about it.

Bottom line. On the art of record, claims 2, 3 and 9 (filter) and claims 4, 5 and 11 (absorber in the leak path) look strongly obvious — EP '935 and US '915 are near-direct hits in the same field. Independent claims 1 and 8 are also vulnerable, primarily through EP 0 364 935 (Kirk Acoustics) in view of US 5,168,527 (LZR) and US 4,029,170 (B&P), with US 4,727,583 (Motorola) supplying the identical problem statement and the equalization teaching; the combination's only soft spot is the relocation of the LZR stepped standoff from a PCB to a ported acoustic wall. Claims 6, 7 and 10 are moderately obvious on the enclosure-damping art. These are technical, art-based conclusions and not a legal opinion of invalidity.