Create a Driver CTQ Register

Record part number, supplier, manufacturing site where controlled, magnet and frame configuration, nominal impedance, polarity convention, dimensions, mounting features, gasket, terminal, cone, surround, spider, dust cap, voice coil, adhesives, tinsel leads, and trace code. Link each characteristic to function and inspection.

The sample-comparison guide helps keep the approved driver attached to an identified system sample.

Verify Documents, Labels, and Lot Traceability

Compare purchase specification, approved drawing, deviation status, supplier certificate or report where required, label, carton, unit marking, date/lot, quantity, and physical construction. Photograph the lot and quarantine mixed or unreadable codes.

Do not accept a supplier substitution under the same customer part number without engineering approval. Cone, surround, spider, coil, magnet, adhesive, frame, or process changes can move acoustic and thermal behavior.

Inspect Mechanical and Cosmetic Condition

Use a controlled fixture or drawing method for frame diameter, height, mounting holes, gasket, terminal, and critical clearances. Inspect cone dents, surround damage, adhesive overflow or gap, dust, metal particles, shifted magnet, bent frame, loose lead, terminal damage, corrosion, and foreign material.

Distinguish cosmetic limits from functional defects. A small mark in a hidden area may be acceptable; contamination in the gap or a warped seal surface is not merely cosmetic.

Separate Screening from Characterization

Screening should be fast, repeatable, and connected to known failure modes. Characterization uses more complete equipment and controlled conditions to compare response, sensitivity, impedance behavior, parameters where specified, and thermal or excursion performance.

Make Rub-and-Buzz Testing Reproducible

Define fixture, baffle or free-air condition, signal, frequency range, level, duration, microphone or sensor, background noise, algorithm or listening method, and reject examples. Handle the driver consistently; finger pressure or an uneven fixture can create or hide rub.

Keep known good and known defect references. Validate that the station detects voice-coil rub, loose lead, adhesive debris, frame vibration, and other targeted failures without rejecting normal suspension noise.

Correlate Incoming Results with the Complete Speaker

Install sampled drivers in production-intent cabinets or use first-off units. Check polarity, seal, torque, response, sensitivity, buzz, limiter behavior, and sound balance. A driver can pass free-air screening and fail when cabinet pressure, grille, or mounting exposes a problem.

The sound-consistency guide helps link incoming limits to the system result instead of controlling numbers with no buyer consequence.

Define Sampling and Reaction by Risk

Set critical, major, and minor failure handling, sample size, tightened or reduced inspection rules where approved, lot rejection, sorting, supplier notification, line containment, and requalification triggers. A failed acoustic sample may require a wider hold than one cosmetic defect because mixed units can already be on the line.

Use the speaker defect-classification guide to align incoming disposition with final inspection language. Review cost, lead time, replacement, rework, line stop, warranty, and shipment impact.

Driver Lot Release Record

• Drawing, part, supplier site, construction, lot, labels, reports, quantity, and deviation status are verified.
• Frame, mounting, gasket, terminal, cone, surround, dust cap, leads, magnet, adhesive, and contamination are inspected.
• Electrical value and polarity use a controlled fixture and convention.
• Rub-and-buzz screening has signal, level, fixture, background, references, and validated defect detection.
• Acoustic characterization and first-off complete products monitor sensitivity, response, seal, limiter, and sound balance.
• Sampling, lot hold, sorting, supplier response, line containment, and requalification are risk based.
• Results trace to the driver lot and complete-speaker production lot.
• Material, supplier, site, process, tooling, or design changes require approved qualification before use.

References

• International Electrotechnical Commission, IEC 60268-21:2018 — acoustical output-based measurements for active systems.