Separate basic selection data from advanced test data
Basic data decides whether a model can enter sampling: length, width, thickness, tolerances, mounting, outlet structure, connection position, impedance, rated power, drive conditions, formal SKU, datasheet and drawing. Advanced data is for higher-risk projects: complete SPL conditions, F0, frequency response, impedance curve, distortion, noise, lot comparison and device-level testing. A simple alert project does not necessarily need every advanced test in the first inquiry; the supplier should state what is documented and what requires project testing.
Mechanical evaluation
Review the complete envelope: mounting surface, holes, wire or terminal exit, rear and front cavities, outlet, grille clearance and tolerance stack-up. For an enclosed speaker, include rear volume, sealing, outlet path and the device housing in the requirement. A nominal outline match does not guarantee installed acoustic or assembly performance.
Electrical evaluation
Evaluate impedance with the amplifier: because speaker impedance varies with frequency, it affects current demand at the specified frequency and voltage rather than acting as one fixed value across the band. Amplifier matching also depends on output voltage/current capability, signal, limiting, cooling and the actual operating condition. TI SLOA105 relates output voltage, load impedance and output power; TI SLOA068A recommends evaluating actual voltage and current when the load varies with frequency. Rated power also depends on waveform, cooling and test duration. Define drive voltage/power, signal type, limiting and protection instead of only writing “1 W speaker”. Clipping, over-current or load mismatch can create distortion and reliability risk.
Acoustic data
SPL must include frequency, input, distance, angle, baffle/IEC condition, averaging method and tolerance. Results from different conditions must not be ranked as if they were directly comparable. F0 identifies a resonance region but does not describe complete system bass. Frequency response shows acoustic level versus frequency, while an impedance curve shows the electrical load versus frequency and can help identify resonance and amplifier loading. A Knowles receiver datasheet presents impedance and SPL curves together and states that measurement data are reference data for the model. Ask for the conditions behind each number, rather than ranking isolated dB values.
Document and sample identity
The product-page SKU, datasheet filename, drawing title block, photo, sample label and connection position should identify one model. If dimensions, thickness, tolerances, maximum-power wording, connection terms or revisions differ, request written confirmation. Similar outlines and development-board data are not substitutes for the formal product record.
Four-stage sample validation
- Mechanical fit and outlet;
- Electrical drive, impedance, polarity, limiting and protection;
- Acoustic measurement under defined conditions;
- Device-level speech, alerts, music, echo, howling, leakage, structural noise and long-term operation.
Record the SKU, drawing/datasheet revision, sample lot, mounting state and result at every stage. Compare supplier fit, documentation, sample support, response quality and lot consistency, not unit price alone.
Enclosed-speaker requirements
An enclosed-speaker inquiry should include the device section, rear/front cavity, outlet, sealing, grille or fabric, mounting surface, wire/terminal position, amplifier condition and acceptance method. Start with Jiachuan’s speaker category or enclosed-speaker category, then verify the exact datasheet, drawing, photo and sample. Commercial terms are model- and project-specific.
FAQ
Must a first inquiry include an impedance curve and THD? Not always. Start with basic selection data and add advanced tests according to project risk.
Why is “rated 1 W” insufficient for amplifier matching? Impedance, drive voltage/current, waveform, clipping and cooling also matter.
Why include the device housing in an enclosed-speaker inquiry? It defines the front cavity, outlet, sealing and mounting boundary.
Project inquiry: provide the application, envelope, connection, drive, sample quantity and acceptance method through the contact page.