Hi,
I have a Behringer UMC204HD interface and have set the volume in Alsamixer for the interface to 100% (=0 dB).
However when using this sine wave generator
https://www.szynalski.com/tone-generator/
set at full volume I get harmonic distortion. When I set the volume in Alsamixer to 93% everything is fine and I get clean sine tones. Can anybody reproduce this and what is typically the best volume to set in Alsamixer?
Alsamixer Volume - Distortion
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- sunrat
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Re: Alsamixer Volume - Distortion
PulseAudio uses ALSA under the hood. I always set volume at 93% in Alsamixer but distortion will also be affected by the level of the source. For some sources 100% will be fine.
That tone generator has a volume level slider, what is that set at? At what frequency do you get distortion? What level is set in pavucontrol?
That tone generator has a volume level slider, what is that set at? At what frequency do you get distortion? What level is set in pavucontrol?
- lilith
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Re: Alsamixer Volume - Distortion
Volumes in Pulse are all set to 100%. It is possible that I changed the default alsa volumes and IIRC they are set below 100% by default. So this might explain it. I thought 100% equals 0dB and it should be fine but obviously this is not always the case. Volume slider on the tone generator page was also set to full volume (which gives a reading of 0dB on the pulse out channel).
- sunrat
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Re: Alsamixer Volume - Distortion
A pure sine wave at 0dB is a pretty hot signal. Do you hear distortion playing music?
Also the "sine wave" from that generator does not seem to be that pure; I noticed harmonics at certain very high or very low frequencies during a quick listen, so other artifacts may be present also.
Also the "sine wave" from that generator does not seem to be that pure; I noticed harmonics at certain very high or very low frequencies during a quick listen, so other artifacts may be present also.
- lilith
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Re: Alsamixer Volume - Distortion
With music it's not obvious. The sine tones should be clean, at least I don't see any distortions with a spectrum analyzer.