I know there is no actual bit-perfect mode on Plexamp, But what would be the closest approximation with the least processing when going out to a USB DAC and Amp?
Obviously no equalizer or loudness leveling, but where to set the preamp and volume? I thought a volume of 100 would maximize the output, but anything above 90 definitely clips.
There must be a combo that comes close to the original input.
I think the preamp setting is only applied if loudness leveling is enabled.
So least processing should (?) be with both loudness leveling and equalizer disabled. I use these settings together with volume slider at max, and at least in my case I don’t hear obvious clipping.
However, I think lowest probability of clipping should come from enabling loudness leveling and setting preamp to 0 … loudness leveling will tend to move many tracks away from the point of clipping.
If you are not a mastering engineer, the concept of “bit-perfect” is nonsense.
The best audio quality you’ll get with
Don’t be fooled by volume differences. Humans tend to perceive louder=better at first, but that is absolutely not true.
agree with much of this (although I think loudness leveling should be a choice/preference, not a requirement to avoid limiting/clipping)
Loudness leveling is simply an “automated volume knob” which changes with every track (but not during the track plays).
If you are going to apply a volume attenuation anyway, there is no fidelity/quality difference between playback with or without loudness leveling.
If all your albums are indeed “proper albums” (which means all tracks of one album are actually ripped from the same master), then you will perceive playback as much more pleasant without the volume jumps between albums (or even tracks, when playing a mixed playlist or radio)
There should be no audible distortion when playback is set up as above. If there is, you probably still have something in the signal path which alters the signal. But it is outside of Plexamp’s influence. (what that might be, can differ. On Laptops for instance, you might have a rather radical sound processing as part of the sound driver software to “enhance” the sound of the rather small inbuilt speakers.)
@TroyDG, you described using a raspberry pi with output to a USB DAC … any additional setup details to share? and just to confirm, do you have strict sample rate matching enabled?
If I understand correctly, loudness leveling as implemented in plexamp can result in limiting/clipping that is not there when loudness leveling is disabled. It’s negligible/minimal for loudness leveling with 0 dB preamp, but at higher preamp settings more tracks will be affected.
Thank you for all the input.
For reference, I have strict sample rate matching enabled and audio is fed to an iFi Zen DAC.
After trying all of these ideas, I ended up with no loudness leveling, no limiter and volume at 100.
The biggest problem turned out to be the loudness leveling. On tracks that are mostly quiet except for a few really loud spots (like Stravinsky’s Firebird) even with the preamp set to zero it would clip the loud orchestral strikes in the middle of the piece.
The lack of leveling isn’t a huge issue in this scenario since the amp is setting next to me with a volume knob.
Good to hear you found settings that helped.
It makes sense that you had distortion at peaks during orchestral music when loudness leveling was enabled … that type of music often has relatively high dynamic range and low average loudness, so loudness leveling will often turn the volume up, which pushes the peaks too high.
I still get some clipping with volume set at 100. Which kinda makes sense. If a given track was mastered rather quiet you would still need a way to increase the volume beyond its normal level if you are relying solely on digital amplification.
Makes me wonder what the baseline level is in the volume then. Somewhere around 90 maybe.
I’ve always assumed that the plexamp max volume slider setting is for 1x, 100% (not like, for example, VLC where the max slider clearly goes > 100%)
Hopefully someone here can confirm
Just did a rough check comparing the output level from plexamp (with volume slider set at max) vs. the output level playing same track with a different app (mpv) with its volume slider set to 100% (mpv has clearly labeled scale and option to increase output > 100%).
My integrated amp has VU meters, and I chose a track with relatively constant output level … in both cases (plexamp and mpv), the VU meters show the same output level.
This suggests that plexamp max volume slider setting is 1x or 100%, and not applying any additional amplification. Good enough evidence for me (and it’s likely this is also documented somewhere and I just haven’t found it yet.)
Yeah, with loudness leveling (and EQ) disabled, we shouldn’t be touching the bits with respect to gain at all.
Thanks @elan for confirming.
@TroyDG maybe one more thing you might look at (outside of plexamp) if you think you’re still hearing some clipping … on the pi, run alsamixer and see if there’s a dB gain setting for your USB DAC (often there isn’t) … if one exists, make sure it isn’t set to a value > 0 dB (or even reduce it a bit below 0 dB for extra headroom)
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