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Reverse-engineering my speakers' API to get reasonable volume control

(jamesbvaughan.com)
287 points jamesbvaughan | 3 comments | 25 Jul 24 15:11 UTC | HN request time: 0s | source
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rectang ◴[27 Jul 24 01:24 UTC] No.41083828[source]▶
> Those methods either give me a tiny slider that I can only use 10% of or about 15 steps where the jump from step 3 to step 4 takes the speakers from “a bit too quiet” to “definitely bothering the neighbors” levels.

Volume controls need to be logarithmic, not linear.

To a first degree approximation, everybody gets this wrong.

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TheNewAndy ◴[27 Jul 24 04:59 UTC] No.41084547[source]▶
Volume controls also shouldn't just be a flat wideband gain - they should respect how we actually perceive sound so the timbre doesn't change as the level changes (when you turn the volume down, you are typically left with just the stuff in the vocal frequency range, and lose all the bass etc).

Doing this stuff well is pretty hard (e.g. designing filters that can do that kind of volume adjustment is hard because you want to be constantly adjusting them, which means you need to be super careful with your filter state) but I have heard what it sounds like, and once you hear it you get angry at all other volume controls.

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1. jamesbvaughan ◴[27 Jul 24 05:26 UTC] No.41084616[source]▶
> Volume controls also shouldn't just be a flat wideband gain - they should respect how we actually perceive sound so the timbre doesn't change as the level changes (when you turn the volume down, you are typically left with just the stuff in the vocal frequency range, and lose all the bass etc).

The amp I'm upgrading from was interesting in this regard. In addition to the main volume knob, it had a loudness knob. The manual actually recommended keeping the volume knob fixed most of the time and using the loudness knob to set the listening level throughout the day.

From the manual:

> 1. Set the LOUDNESS control to the FLAT position.

> 2. Rotate the VOLUME control on the front panel (or press VOLUME +/– on the remote control) to set the sound output level to the loudest listening level that you would listen to.

> 3. Rotate the LOUDNESS control counterclockwise until the desired volume is obtained.

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2. XlA5vEKsMISoIln ◴[27 Jul 24 11:23 UTC] No.41085831[source]▶
Amazing. This is probably the correct way do make amp controls. I'd say the volume should be a multi turn trim potentiometer in the back of the device so you don't have to brief your guests on correct operation.
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3. ds_opseeker ◴[28 Jul 24 11:45 UTC] No.41092597[source]▶
Yes, a stepped attenuator.