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Bad quality sound on MoodeAudio 6.x
#51
(06-25-2020, 03:08 PM)vinnn Wrote:
(06-25-2020, 02:34 PM)AlexTee Wrote: Are you serious now? You don't hear the sandy distortion? Please, put on your headphones.

Did you ever read my posts carefully regarding the recording technique and ALSA volume levels? Please, re-read, otherwise you're missing lots of info.

Who else can confirm they don't hear that? Smile

What are you trying to see on the graphic? It is not heavy clipping, it is just a distorted datastream, fed to DAC input, that's not an issue with analog output! Sorry, I might have expressed myself wrong. Let's avoid clipping term and just call it distortion, ok? Now, you wanna hear the heavy distortion? Check out the third file, I've posted above.

Apologies if I missed some details there, didn't read through the entire thread tbh. Also I accidentally posted too early and amended my post seemingly whilst you were replying to me. Smile
But yeah there is some mild clipping apparent if I crank it, more apparent through my AKG cans but this appears to be the clipping in my screenshot, not all out distortion.

'EQ on' sample demonstrates, that there is a distortion even on default presets, that come with the release, while 'EQ distortion' just empathizes it for clarity.
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#52
To wrap up my involvement in this issue, I spent a fair amount of time last evening trying to understand the alsa eq10 plugin. I didn't learn much. There's too little documentation of the code.

However, here's an interesting tidbit from Eq.cc

Code:
PortInfo
Eq10::port_info [] =
{
    {"31 Hz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"63 Hz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"125 Hz", CTRL_IN | GROUP, {DEFAULT_0, -48, 24}},
    {"250 Hz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"500 Hz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"1 kHz", CTRL_IN | GROUP, {DEFAULT_0, -48, 24}},
    {"2 kHz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"4 kHz", CTRL_IN, {DEFAULT_0, -48, 24}},
    {"8 kHz", CTRL_IN | GROUP, {DEFAULT_0, -48, 24}},
    {"16 kHz", CTRL_IN, {DEFAULT_0, -48, 24}},

    {"in", INPUT | AUDIO},
    {"out", OUTPUT | AUDIO}
};

and similarly for Eq10X2 (two channels).

The numbers in this structure correspond to db values in an unexplained table found in the CAPS webpage.

I interpret it to mean that the default gain in an octave band is 0db, the minimum possible gain is -48db, and the maximum possible gain is +24db. (That's a huge variation in gain!)

There is a predefined "Flat" curve available for the graphical equalizer. The preset values there are 66 across the board. One might infer for this and the above that in this plugin the value 66 corresponds to 0db, the value 100 to +24db, and the value 0 to -48db. A small change would have a big effect.

Or maybe I'm just deluding myself. Tongue

Regards,
Kent
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#53
I think, it is quite obvious, that the issue is with EQ adding out-of-range gain.

And the evidence you brought looks pretty legit.
Let me add, that 66 (default) point is probably higher than 0dB, as it already adds distortion. The 0dB is closer to 50-55.

Thanks, appreciate your efforts!
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#54
While working on moOde 7 series I went back and did an A/B of the Graphic EQ Flat curve against EQ OFF and there is definitely a loudness increase when set to Flat :-0

It appears that the alsaequal default setting of 66 for "Flat" is not correct and actually needs to be reduced by 6 of the strange alsaequal units to achieve zero loudness increase, at least to my ear.
Enjoy the Music!
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#55
Quote:It appears that the alsaequal default setting of 66 for "Flat" is not correct and actually needs to be reduced by 6 of the strange alsaequal units to achieve zero loudness increase, at least to my ear.

Oh Tim !  That must make it hard wearing sunglasses.... Tongue Big Grin

Cheers and beers..!
Bob.

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#56
LOL
Enjoy the Music!
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#57
(08-08-2020, 02:50 AM)Tim Curtis Wrote: While working on moOde 7 series I went back and did an A/B of the Graphic EQ Flat curve against EQ OFF and there is definitely a loudness increase when set to Flat :-0

It appears that the alsaequal default setting of 66 for "Flat" is not correct and actually needs to be reduced by 6 of the strange alsaequal units to achieve zero loudness increase, at least to my ear.

Hi. I'm glad, you now confirm, there's an issue. It was quite obvious, that the issue is with alsaequal. Cheers! Excited to try the new release.
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#58
I don’t use eq but since adding boost in an eq is almost always going to lead to distortion maybe it’d be better to have it so 60 (or whatever the flat equivalent is) was the upper limit and set the base lower and let users shape the curve accordingly. If each unit really is a dB then we should drastically alter the scale so it’s +/- something reasonable instead of providing the full range possible.
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#59
The Alsaequal UI doesn't display dB and Ive never been able to find info about the mapping between it's 0-100 scale and dB. it defaults to 66 which one would assume is "Flat" ?? The UI is displayed via sudo alsamixer -D alsaequal

Apparently now though 66 is louder than with no EQ. It doesn't look like the plugin itself has changed given the dates in the source repo so prolly something changed in ALSA itself.

The sources for alsaequal are here
https://github.com/raedwulf/alsaequal

Maybe there is another graphic eq plugin that could be used that uses a dB scale. That would be something like -12 0 12 where 0dB gain is "Flat".
Enjoy the Music!
moodeaudio.org | Mastodon Feed | GitHub
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#60
Hi Tim.
I'm back to report, that the issue is apparently gone on release 7. Enjoying the EQ now.

So, was ALSA the culprit?
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