PC volume and output THD

[Mark1]

In general, does increasing PC volume toward max volume (100) drive the sound card output into higher distortion or even clipping? I was using PC headphone jack into receiver CD input.. The phone output voltage is a little low for the receiver 500mv input sensitivity, so I would want to use high PC volume. It seemed like the signal was cleaner at lower PC volume maybe at about "80" but I'm really not sure.

My understanding of clipping is the signal voltage through an amplifier is too high, but I know that if the load impedance is lower distortion increases (current too high?). So I wondered how PC output distortion could increase near max volume through the receivers high 50k Ohm impedance if the PC amp isn't clipping which it's not.

 

[Mark1]

I don't use headphones but sometimes also play music on the laptop through its speaker or even on cell phone and notice distortion rises near max volume and wasn't sure if it was speaker or amplifier distortion I suspect mostly the latter, but a speaker is a lot heaver load.

Where it leads to I think I need a better source than PC headphone out to stream music at high fidelity , either a streamer or a network receiver.

 

[Mark1]

Probably seems I'm talking to myself here, but I'm sure someone will come along and reply to my elementary questions .

I was looking at a review of the WiiM Pro and see it has adjustable fixed line out. My receiver's input sensitivity is 500mv, so this seems idea. This should give me consistent volume between sources like tuner and streaming, there be no reason to use 800mv and higher output setting, right?

The WiiM Pro also comes with four selectable (fixed) output levels. While I did not test precisely the behaviour of digital attenuation at different level in the analog domain, (but I did catch THD+N at different digital volume below), I measured each of the output settings and expected a logical drop in performance. Yet, for some reason, the opposite happened:

2Vrms : -88.8dB THD+N
1Vrms : -92.8dB THD+N
800mV : -93.1dB THD+N
500mV : -93.2dB THD+N

Finally, the best performance I could have measure out of the DAC has been when set at 0.5Vrms:

 

[DVDdoug]

Usually a soundcard or DAC is "calibrated" so the digital data clips first and the analog-side has some unused headroom.

You can clip the digital data with EQ boost or some applications (like VLC) can go over 100% and clip.

2Vrms : -88.8dB THD+N

You aren't usually going to hear anything that "quiet", especially distortion which will be masked (drowned-out) by the signal.

Noise is trickier because you might hear it during "silence" and the absolute noise level depends on analog gain, speaker (or headphone sensitivity), how close you are to the speakers, other ambient room noise, etc. And noise is analog and it won't go down when you turn down the digital volume.

And you'll know if you are hearing noise (hum, hiss, or whine in the background).

 

[Mark1]

Usually a soundcard or DAC is "calibrated" so the digital data clips first and the analog-side has some unused headroom.

You can clip the digital data with EQ boost or some applications (like VLC) can go over 100% and clip.


You aren't usually going to hear anything that "quiet", especially distortion which will be masked (drowned-out) by the signal.

Noise is trickier because you might hear it during "silence" and the absolute noise level depends on analog gain, speaker (or headphone sensitivity), how close you are to the speakers, other ambient room noise, etc. And noise is analog and it won't go down when you turn down the digital volume.

And you'll know if you are hearing noise (hum, hiss, or whine in the background).

But turning up the music app or player like on Spotify to max volume won't clip the digital data will it? I always have the player or app at max volume, and have to turn the analog PC sound volume to near max to get any adequate volume. Anyway it seems the WiiM would solve all these matters except for where to set music player/app volume.

 

[wwenze]

1) Usually the individual software player is smart enough to not enter digital clipping zone, unless you're playing multiple tracks at once

2) Usually the Windows OS is smart enough to not enter digital clipping zone, unless you're playing multiple program at once

3) A properly-designed (personal opinion) soundcard will have maximum SINAD at 0dBFS (maximum digital output level). A typical soundcard will have best performance at 90~95% and then distortion starts to rise slightly towards 0dBS but still below audibility and still not clipping.
*And even then this should not discourage you from using max volume since 99% of the time the actual music material itself is not 0dBFS.

4) A properly-designed soundcard will output 0dBFS at 2Vrms. However, computer motherboard onboard sound, phones, cheap dongles do not count as properly-designed soundcard and will often output lower voltage

 

[pablolie]

But turning up the music app or player like on Spotify to max volume won't clip the digital data will it? I always have the player or app at max volume, and have to turn the analog PC sound volume to near max to get any adequate volume. Anyway it seems the WiiM would solve all these matters except for where to set music player/app volume.

You can always overdrive speakers/headphones with enough amplification, a mismatch and hamfisted operation of the volume button. There's no awareness of other devices' capabilities and limitations in "the chain".

 

[Mark1]

1) Usually the individual software player is smart enough to not enter digital clipping zone, unless you're playing multiple tracks at once

2) Usually the Windows OS is smart enough to not enter digital clipping zone, unless you're playing multiple program at once

3) A properly-designed (personal opinion) soundcard will have maximum SINAD at 0dBFS (maximum digital output level). A typical soundcard will have best performance at 90~95% and then distortion starts to rise slightly towards 0dBS but still below audibility and still not clipping.
*And even then this should not discourage you from using max volume since 99% of the time the actual music material itself is not 0dBFS.

4) A properly-designed soundcard will output 0dBFS at 2Vrms. However, computer motherboard onboard sound, phones, cheap dongles do not count as properly-designed soundcard and will often output lower voltage

Thanks for the thorough reply. I see there's a lot of usuallys and dependent on proper design and I don't know if the stock RealTek sound card in this Dell Inspiron 15 and Windows 10 is meeting that. I think the stream of Spotify through the headphone out to my receiver sound probably as good as the bitrate allowed but I think turning the headphone out volume to max might have cause audible distortion, I'm not sure.

With 4, it appears the headphone out was not near 2V. I had to turn the receiver volume up a lot more than with the integrated tuner which I assume is at the receivers input sensitivity of 500mv but that may not be correct.

 

[Mark1]

You can always overdrive speakers/headphones with enough amplification, a mismatch and hamfisted operation of the volume button. There's no awareness of other devices' capabilities and limitations in "the chain".

Well the headphone out was underdriving the input of my receiver, but what I wonder is does the PC volume control (which I believe controls the analog output of the sound card able to overdrive the output.

 

[AnalogSteph]

Thanks for the thorough reply. I see there's a lot of usuallys and dependent on proper design and I don't know if the stock RealTek sound card in this Dell Inspiron 15 and Windows 10 is meeting that. I think the stream of Spotify through the headphone out to my receiver sound probably as good as the bitrate allowed but I think turning the headphone out volume to max might have cause audible distortion, I'm not sure.

OEM systems often ship with sound misimprovements of occasionally changing names (e.g. Waves MaxxAudio) that may need to be uninstalled even after you have installed a generic Realtek driver. Worth keeping an eye out for.

If you want to know whether your audio output is prone to distortion, you can use the tone generators of Audacity or REW, for example. Generate a maybe 50-100 Hz tone of no more than 0.985 (-0.13 dBFS) amplitude and play that (through your proper system, not the tiny laptop speakers).

Distortion at high volume (above ca. 80 or ~-3 dB) has been known to happen occasionally with chips rated to work at both 3.3 and 5 V. The analog stage can clip under these circumstances. Normally things would be designed such that they can reproduce at least a full 0 dBFS. Ideally it even is a few dB more. If you happen to be affected by this, getting an external DAC of sorts capable of 2 Vrms output would be worth considering. It probably wouldn't be any more expensive than just adding a line preamplifier of sorts.

 

[Mark1]

OEM systems often ship with sound misimprovements of occasionally changing names (e.g. Waves MaxxAudio) that may need to be uninstalled even after you have installed a generic Realtek driver. Worth keeping an eye out for.

If you want to know whether your audio output is prone to distortion, you can use the tone generators of Audacity or REW, for example. Generate a maybe 50-100 Hz tone of no more than 0.985 (-0.13 dBFS) amplitude and play that (through your proper system, not the tiny laptop speakers).

Distortion at high volume (above ca. 80 or ~-3 dB) has been known to happen occasionally with chips rated to work at both 3.3 and 5 V. The analog stage can clip under these circumstances. Normally things would be designed such that they can reproduce at least a full 0 dBFS. Ideally it even is a few dB more. If you happen to be affected by this, getting an external DAC of sorts capable of 2 Vrms output would be worth considering. It probably wouldn't be any more expensive than just adding a line preamplifier of sorts.

Thanks, I'll try to look into using those signal analyzer programs.

One thing I'm not clear on is does the app volume such as Spotify control the audio signal voltage/volume at the digital stage, and the PC main volume control the analog stage volume? I don't see why apps should even have a volume control.
Also I wonder why it's recommended a DAC is capable of 2 Vrms output, when a power amp sensitivity may be under 500 mV. Is this mostly a matter of the DAC having headroom and capability and versatility?

 

[pablolie]

..
One thing I'm not clear on is does the app volume such as Spotify control the audio signal voltage/volume at the digital stage, and the PC main volume control the analog stage volume? I don't see why apps should even have a volume control.

It depends on how you set up your audio. If you give applications "exclusive control", they bypass the Windows access control and high the audio resource control. Some like to eliminate the middleman, some don't care. I personally don't hear better qudio quality when I give Rover Media Center exclusive control.

Also I wonder why it's recommended a DAC is capable of 2 Vrms output, when a power amp sensitivity may be under 500 mV. Is this mostly a matter of the DAC having headroom and capability and versatility?

Power/voltage mismatchea are basic audio chain considerations. Little to do with the OS on the computers.

 

[Mark1]

It depends on how you set up your audio. If you give applications "exclusive control", they bypass the Windows access control and high the audio resource control. Some like to eliminate the middleman, some don't care. I personally don't hear better qudio quality when I give Rover Media Center exclusive control.


Power/voltage mismatchea are basic audio chain considerations. Little to do with the OS on the computers.

I'm not giving Spotify or any app exclusive audio control. There's seems to always be two volume controls one on the app and the other a PC or cell phone master volume. I was just wondering what stages the volumes controls operate on.

I was asking about DAC output voltage separate and apart from computers and software volume controls. I'd rather just eliminate the PC and variable volume control all together for a set output stand alone DAC. I know I personally want a good match between source output voltage and power amplifier input sensitivity. That's why I ask why it's important a DAC is capable of 2 V output, a much higher output than the power amp needs.

I see in this thread that DAC volume is controlled in the digital domain https://www.audiosciencereview.com/...olume-control-vs-analog-volume-control.20512/

 

[Mark1]

Most on here probably know all this but for others less knowledgeable like myself lol, after doing some reading and consistent with replies in this thread, it seems PC/DAC volume should be set at 70%-80%. This volume level will prevent possible digital distortion or clipping but be high enough to prevent resolution loss of lower volume level. The music app or player should be set at 100% for full resolution. This also agrees with my listening impressions that best sound was with player at max volume and PC around 80%.

 

[RayDunzl]

In general, does increasing PC volume toward max volume (100) drive the sound card output into higher distortion or even clipping?

Couldn't you plug the analog output of your sound device into an analog input and let REW take a look at what you have going?

Even if just for grins.

 

[Mark1]

Couldn't you plug the analog output of your sound device into an analog input and let REW take a look at what you have going?

Even if just for grins.

Yeah I think I could. I never used REW or know much about it but I'll have to look into it.

 

[AnalogSteph]

I know I personally want a good match between source output voltage and power amplifier input sensitivity. That's why I ask why it's important a DAC is capable of 2 V output, a much higher output than the power amp needs.

I wouldn't call that much higher. It is not uncommon to see power amplifiers with a nominal input sensitivity of 1-1.6 V, which is 6 dB away at best. This is a far better match than for a multitude of classic preamps, many of which can dish out 6-9 Vrms and some a lot more still (possibly for use with classic transformer-coupled tube power amps which may have voltage gains in the teens of dB only).

 

[Mark1]

I wouldn't call that much higher. It is not uncommon to see power amplifiers with a nominal input sensitivity of 1-1.6 V, which is 6 dB away at best. This is a far better match than for a multitude of classic preamps, many of which can dish out 6-9 Vrms and some a lot more still (possibly for use with classic transformer-coupled tube power amps which may have voltage gains in the teens of dB only).

Yeah, I was thinking much higher for my particular amplifier, but I see not high at all for amplifiers and compatibility in general.