Circuit Atlas · HUSH M4 · Rev 2027.4 draft
8 Measurement plan
How figures in section 6 would be measured when a unit exists. No results are given here.
IN DEVELOPMENT · REV 2027.4 (DRAFT) · DESIGN TARGETS, NOT MEASUREMENTS
HUSH M4 is in development. This draft is published on zakkhutoretsky.com; it has no price and no ordering. Figures marked design target are goals for the finished product. Figures marked calculated come from the published formulas. No value on these pages was measured on a built unit. Interviews are cited as the design brief, not as an endorsement.
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8 Measurement plan
When a unit exists, the figures in section 6 would be measured following the methods of IEC 60268-3R9 and reported with the test conditions (source impedance, load, bandwidth, weighting, reference level). Until then the table in section 6 remains a list of design targets. AES17, the method for digital audio equipment, would apply to the optional USB-C interface (S10). Publication plan (method only): every result would be published with its test conditions, the instrument and its settings, the number of units tested and the raw files, and a figure would appear on the product pages only after it has been measured on a real unit. No result is given here.
| Quantity | Condition (proposed) | Instrument |
|---|---|---|
| Frequency response | Line in to master out, 1 kHz reference, 10 Hz to 40 kHz | Audio analyser or swept generator + scope |
| THD+N | +4 dBu, 1 kHz, 22 Hz–22 kHz bandwidth and 80 kHz bandwidth | Audio analyser |
| Signal-to-noise | Ref +4 dBu, A-weighted, inputs terminated with 150 Ω (line) / 47 kΩ + 200 pF (phono) | Audio analyser |
| Crosstalk | Drive one channel, measure the others, 1 kHz and 10 kHz | Audio analyser |
| Maximum output | Clipping point into 600 Ω and 10 kΩ, balanced | Scope + analyser |
| Filter bypass | Switch the dead-zone relay with a steady tone, record the largest sample step against the tone’s own step | Scope or recorder |
| USB-C record path | Loop a known level from a generator through the tap; compare file level and noise with the analogue measurement | Audio analyser + recording software |
| Texture | Each mode with a swept tone at three amounts; record level, noise and any aliasing products | Audio analyser |