Does bit perfect matter?

[Giro413]

Just trying to find out if I should at all worry about getting a bit perfect output from my WiiM Pro Plus to my Denon receiver, connected via line out. I mean, does it audibly matter in terms of sound quality that the eq is off and the volume is fixed at 100%? Apart from how loud it will sound, of course.
I am inclined to fix the volume at 75% to match the level of my turntable, so I have a similar volume level between sources on my receiver- and don’t get a chock if I forget to turn down the volume after switching from turntable to line in.
I might also want to play with the eq, but I am not certain that I will use it.
Should I aim to make the connection to my receiver “bit perfect” and just turn down the volume on the receiver accordingly (if we assume that I will not be using the Wiim’s eq) or does that really not make an audible difference to non-audiophiles like me, who just want the best result within reason.
Ps. I know that the best way is to test for myself, but what are your thoughts?
Thanks in advance.

 

[Mr Ee]

Just trying to find out if I should at all worry about getting a bit perfect output from my WiiM Pro Plus to my Denon receiver, connected via line out. I mean, does it audibly matter in terms of sound quality that the eq is off and the volume is fixed at 100%? A part from how loud it will sound, of course.
I am inclined to fix the volume at 75% to match the level of my turntable, so I have a similar volume level between sources on my receiver- and don’t get a chock if I forget to turn down the volume after switching from turntable to line in.
I might also want to play with the eq, but I am not certain that I will use it.
Should I aim to make the connection to my receiver “bit perfect” and just turn down the volume on the receiver accordingly (if we assume that I will not be using the Wiim’s eq) or does that really not make an audible difference to non-audiophiles like me, who just want the best result within reason.
Ps. I know that the best way is to test for myself, but what are your thoughts?
Thanks in advance.

Bit perfect refers to a digital output signal, not the analog one via line out.

I'd say don't worry about it - do whatever makes listening to and enjoying the music easiest.
Maybe one day if you want a 'serious' listening session you could set volume back to 100%.
And then realise that you probably can't tell the difference!!

 

[Hiphiman]

Bit perfect refers to a digital output signal, not the analog one via line out.

I'd say don't worry about it - do whatever makes listening to and enjoying the music easiest.
Maybe one day if you want a 'serious' listening session you could set volume back to 100%.
And then realise that you probably can't tell the difference!!

I agree with Mr Ee. Pursuing bit perfection is only of relevance if you were to connect to your receiver with a digital optical or coax lead, thereby using the Denon’s DAC rather than the WiiM’s. Indeed, setting the line out to 100% may not be preferable for the Denon or the WiiM‘s sound quality.

 

[Giro413]

Thank you, both. Just the answer I was hoping for

 

[CrystalGipsy]

If you alter the volume in the digital realm ie the Wiims volume it’s no longer bit perfect to the dac it’s attenuating the digital side pre dac as it has no analogue preamp. Whether you notice any difference depends on the devices implementation of how it does it and your ongoing system and ears. If you wanted to maintain MQA signaling via digital out this would destroy it. To maintain as close to original precision you need to to perform attenuation in 32bit or higher not sure the Wiim does this. You could change the output level of the line level to be a lower voltage if the 2mv output is too high. This does give the device more headroom I believe.

 

[Giro413]

If you alter the volume in the digital realm ie the Wiims volume it’s no longer bit perfect to the dac it’s attenuating the digital side pre dac as it has no analogue preamp. Whether you notice any difference depends on the devices implementation of how it does it and your ongoing system and ears. If you wanted to maintain MQA signaling via digital out this would destroy it. To maintain as close to original precision you need to to perform attenuation in 32bit or higher not sure the Wiim does this. You could change the output level of the line level to be a lower voltage if the 2mv output is too high. This does give the device more headroom I believe.

Thank you. So if i understand you correctly, I could use the xx-mv output function to lower the volume while retaining bit-perfectness. That might be worth a shot. I have noticed that volume drops if i choose a smaller number for vm. But doesn't this alter something else apart from volume level through line out? It was set at 2vm as the result of some system test during the initial setup of my Wiim Pro Plus.

 

[CrystalGipsy]

It may require more gain amplifier side if lowering it below 2mv and as a result can up the noise level when playing higher volumes but if it’s too high on input it can clip the amp before its normal limits. I have it reduced to my powered speakers as it was too hot at 2mv and clipped. Sounds much nicer at 1mv. On the amp before it had adjustable sensitivity and sounded fine with it at 2mv. It’s all amp dependant really.

But I would not worry about using the volume on the device unless you really notice a decrease in quality.

 

[dtc]

Some background on "bit perfect" audio.

The idea of bit perfect audio came about in the early days of computer audio when people realized that the Windows "mixer" was making unknow changes to the data. It was not just volume, but the data would also get re-sampled to other sample rates. The user or the player had little or no control over these changes. So, methods were developed to bypass the mixer and send the exact bits that were in the file to the digital output. This is bit perfect audio.

Although volume changes technically break bit perfect data, the algorithms that change the volume in the digital domain are done with much more precision that the actual data, so volume adjusted data is usually considered to be bit perfect. This applies to PCM data. DSD data is a very different format and there is no easy way to change its volume in the digital domain.

Any DSP (Digital Signal Processor), such as re-sampling or equalizers, do break bit perfectness. However, people routinely use methods like equalizers to adjust their output, since it is a conscious choice made by the user, not an unknown, behind the scene change like the Windows mixer makes. If the DSP changes the sound and you like the sound, don't worry about whether it is bit-perfect or not.

As to output voltage, line-in circuitry is designed to handle a certain voltage. Consumer equipment is often designed around a 1 volt signal, whereas professional and high-end consumer equipment is usually designed to accept 2v or higher signals. The line-out voltage should be set to match the line-in voltage of the DAC or receiver. If the line-out voltage is too low, the volume will be reduced. If line-out is too high it will saturate the line-in circuitry and cause errors in the data. With properly designed systems, as long as the line-out and line-in voltages are roughly matched, the digital signal should not be affected by the voltage level.

Bottom line - Set the line-out volume as appropriate, apply DSPs (equalizer) as appropriate and don't worry about being bit perfect.

 

[Giro413]

Some background on "bit perfect" audio.

The idea of bit perfect audio came about in the early days of computer audio when people realized that the Windows "mixer" was making unknow changes to the data. It was not just volume, but the data would also get re-sampled to other sample rates. The user or the player had little or no control over these changes. So, methods were developed to bypass the mixer and send the exact bits that were in the file to the digital output. This is bit perfect audio.

Although volume changes technically break bit perfect data, the algorithms that change the volume in the digital domain are done with much more precision that the actual data, so volume adjusted data is usually considered to bit perfect. This applies to PCM data. DSD data is a very different format and there is no easy way to change its volume in the digital domain.

Any DSP (Digital Signal Processor), just as re-sampling or equalizers, do break bit perfectness. However, people routinely use methods like equalizers to adjust their output, since it is a conscious choice made by the user, not an unknown, behind the scene change like the Windows mixer makes. If the DSP changes the sound and you like the sound, don't worry about whether it is bit-perfect or not.

As to output voltage, line-in circuitry is designed to handle a certain voltage. Consumer equipment is often designed around a 1volt signal, whereas professional and high-end consumer equipment is usually designed to accept 2v or higher signals. The line-out voltage should be set to match the line-in voltage of the DAC or receiver. If the line-out voltage is too low, the volume will be reduced. If line-out is too high it will saturate the line-in circuitry and cause errors in the data. With properly designed systems, as long as the line-out and line-in voltages are roughly matched, the digital signal should not be affected by the voltage level.

Bottom line - Set the line-out volume as appropriate, apply DSPs (equalizer) as appropriate and don't worry about being bit perfect.

Thank you for a really great explanation! I think I get it now. I especially like your closing comment
I can tell that my Denon DRA-F107 receiver has an input sensitivity of: 2.5mV (MM), 200mV (line), so that means that it is set correctly although the volume is louder than that coming from my turntable. And I will continue to have the volume limiter set to 75% in order to get a similar volume level across sources. And maybe even a little EQ. Thanks again.