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Author Topic: Volume Control and DSD  (Read 5580 times)

Alex M

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Volume Control and DSD
« on: July 25, 2018, 09:39:32 am »

Digital volume control leads to irreversible degradation of the signal. It will be better to avoid this.

By decreasing the volume, you decrease the bit depth. For example, by reducing the level of a 24-bit signal by 6 dB, you will get a 12-bit signal. Therefore, the adjustment of sound power must be done only after the DAC.
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pschelbert

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Re: Volume Control and DSD
« Reply #1 on: July 25, 2018, 09:55:01 am »

by reducing 6dB you will get 23-Bit

24-Bit DAC reducing 48dB you will still have the redbook CD resolution of 16Bit.

If you hear with 110dB SPL (this is really loud!) and you reduce 48dB you will be at 72dB SPL (night volume).

So digital volume-control is at least as good as analog or better (left-right uniformity excellent, not doable analog).
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michael123

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Re: Volume Control and DSD
« Reply #2 on: July 25, 2018, 10:01:07 am »

So digital volume-control is at least as good as analog or better (left-right uniformity excellent, not doable analog).

trust your ears...
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pschelbert

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Re: Volume Control and DSD
« Reply #3 on: July 25, 2018, 10:04:27 am »

yes I do it daily with my digital volume-control enabled
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RD James

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Re: Volume Control and DSD
« Reply #4 on: July 25, 2018, 10:11:18 am »

Disable bitstreaming and have Media Center convert from DSD to high sample rate PCM instead.
Then you can use the internal volume control and volume leveling.
There's little reason to bitstream DSD in my opinion.

Digital volume control leads to irreversible degradation of the signal. It will be better to avoid this.
By decreasing the volume, you decrease the bit depth. For example, by reducing the level of a 24-bit signal by 6 dB, you will get a 12-bit signal. Therefore, the adjustment of sound power must be done only after the DAC.
6 dB is one bit. It doesn't halve the bit-depth.

With Media Center configured to use TPDF dither, there is no degradation of audio quality when using the internal volume control.
The signal to noise ratio is reduced - which means a slight hiss at very high volumes or with high gain amplifiers - but there is no distortion or other perceptible quality loss.
No DAC is 24-bit on its analog output, so that alone gives you a few bits that you can 'lose' without affecting sound quality at all.
There are advantages to digital volume control over analog volume control too, such as perfect linearity and tracking.
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pschelbert

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Re: Volume Control and DSD
« Reply #5 on: July 25, 2018, 10:37:01 am »

My audio chain, player JRiver, at max volume (120dB SPL peak) at 2.5m, you can hear no noise if you play a file with silence.

With real audio files I mostly hear noise at the beginning of the music, digitally enregistered noise and hiss, reproduced with precision :)

DAC has 24-Bit theoretical and ca. 20Bit real resolution. PowerAmps a bit over 105dB SNR.

So, no problem with digital volume control in JRiver.

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Alex M

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Re: Volume Control and DSD
« Reply #6 on: July 25, 2018, 10:52:23 am »

Decibel is a nonlinear measurement value
A change of 6 dB is equivalent to a voltage change of 2 times, a power of 3.98 times.
Therefore, the highest bit is lost and the 24-bit signal becomes 12-bit.

p.s. In MC 1% = 0.5 dB (20-100%)
http://yabb.jriver.com/interact/index.php?topic=69939.msg471528#msg471528
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pschelbert

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Re: Volume Control and DSD
« Reply #7 on: July 25, 2018, 11:11:48 am »

The highest bit is lost so you will have still 23bits.
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Alex M

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Re: Volume Control and DSD
« Reply #8 on: July 25, 2018, 11:14:15 am »

The highest bit is lost so you will have still 23bits.

Looking from which side to consider  :)

Gain -6 db in any audioeditor reduces the signal amplitude by a factor of 2


p.s. It's even strange that such elementary things have to be explained here.
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RD James

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Re: Volume Control and DSD
« Reply #9 on: July 25, 2018, 12:34:49 pm »

Decibel is a nonlinear measurement value
A change of 6 dB is equivalent to a voltage change of 2 times, a power of 3.98 times.
Therefore, the highest bit is lost and the 24-bit signal becomes 12-bit.

p.s. In MC 1% = 0.5 dB (20-100%)
http://yabb.jriver.com/interact/index.php?topic=69939.msg471528#msg471528
That's not how digital audio works. 6.01 dB = 1-bit.
If what you said was true, reducing the volume by only 18 dB would result in 3-bit audio rather than 21-bit.
 
16-bit audio is considered to have a 96 dB dynamic range and 24-bit 144 dB - though that's not strictly accurate when you account for dithering (which improves it).
You 'lose' the lower bits first since you're reducing the volume - though noise-shaped dither can reproduce audio below that theoretical noise floor of -96/-144 dB.
This is an example of a 1 kHz tone encoded at -105 dB in a 16-bit file using noise shaping:

 
Considering the actual dynamic range of music, and how mastering typically pushes the audio into the upper bits, you're not losing any actual audio until you start making significant volume reductions.
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Fitzcaraldo215

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Re: Volume Control and DSD
« Reply #10 on: July 25, 2018, 01:06:04 pm »

Looking from which side to consider  :)

Gain -6 db in any audioeditor reduces the signal amplitude by a factor of 2


p.s. It's even strange that such elementary things have to be explained here.

Right.  But, bit shifting from 24 bits to 23 bits truncating the LSB reduces its integer magnitude by 1/2 (decimals truncated).  So, a 24-bit word can hold a maximum value of 16,777,215, and a 23-bit word 8,388,607. A 12-bit word has a maximum magnitude of 4,095, which is not even remotely close to 1/2 of the 24-bit word.  That is a lot of dB!  So, there is a blind spot in your supposition.

But, if concerned about loss of resolution in digital volume controls, use a 32-bit DAC.  Many, if not most, are these days.

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pschelbert

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Re: Volume Control and DSD
« Reply #11 on: July 25, 2018, 01:50:24 pm »

That's not how digital audio works. 6.01 dB = 1-bit.
If what you said was true, reducing the volume by only 18 dB would result in 3-bit audio rather than 21-bit.
 
16-bit audio is considered to have a 96 dB dynamic range and 24-bit 144 dB - though that's not strictly accurate when you account for dithering (which improves it).
You 'lose' the lower bits first since you're reducing the volume - though noise-shaped dither can reproduce audio below that theoretical noise floor of -96/-144 dB.
This is an example of a 1 kHz tone encoded at -105 dB in a 16-bit file using noise shaping:

 
Considering the actual dynamic range of music, and how mastering typically pushes the audio into the upper bits, you're not losing any actual audio until you start making significant volume reductions.

great explanation.
Don't worry, digital technology is way better than most if not any recording.
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TheShoe

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Re: Volume Control and DSD
« Reply #12 on: July 25, 2018, 06:44:57 pm »

Enable DSD bitstreaming, that way when you play any DSD files it'll automatically bitstream those type of files, while leaving PCM files as-is. You can't control volume or use any DSP while bitstreaming. Typically, volume has to be set at 100%, otherwise you might get just noise when attempting to bitstream DSD.

But... as far as I know, there are a few DACs that do support volume control while bitstreaming. For those DACs there is an option to enable volume while bitstreaming (right click on the speaker icon next to the volume slider, and select "Enable Volume When Bitstreaming").

just hooked up my exasound e38.   they have a nice plugin for jriver that controls the hardware volume on the DAC, which is plugged directly into the AMP.  works beautifully.

when i have it connected to my processor (Marantz av7703), i have volume control from jriver disabled, DAC set to 100%, and the Marantz set to Pure Direct mode and use its volume, which probably still converts the analog back to digital but it sounds just as good

in any case, i have DSD bitstreaming enabled
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Alex M

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Re: Volume Control and DSD
« Reply #13 on: July 25, 2018, 08:16:53 pm »

great explanation.

A false explanation. Confuse.
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Alex M

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Re: Volume Control and DSD
« Reply #14 on: July 25, 2018, 08:47:17 pm »


That's not how digital audio works. 6.01 dB = 1-bit.


It's right. But we need to understand that each bit has its own weight.
For example, for a signal with an amplitude of 2 V:
1 bit: 2 / 21 = 1 V
2 bits: 2 / 22 = 0.5 V
...
24 bit: 2/224 = 0.0000001192092896 V

When you decrease the volume by 6 dB, you reduce the weight of each bits by half. Try to think about it  :)
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RD James

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Re: Volume Control and DSD
« Reply #15 on: July 26, 2018, 12:27:59 am »

You lose the least significant bits first.
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pschelbert

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Re: Volume Control and DSD
« Reply #16 on: July 26, 2018, 01:22:11 am »

to Alex M

I suggest you inform yourself about digitizing, there is a lot of educational material on the web.
It works different. It is as RD_James says.
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Alex M

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Re: Volume Control and DSD
« Reply #17 on: July 26, 2018, 05:45:00 am »

I tried to convey the physical meaning. I know how it works.
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michael123

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Re: Volume Control and DSD
« Reply #18 on: July 26, 2018, 06:14:17 am »

I know very simple thing - in my system if I reduce the volume in JRiver by more than 7-8 db, sound loses dynamics and become flat. I needed to do it with previous Dirac version due to some clipping it introduced on certain albums.

Same was with super-duper digital volume on once mine Logitech Transporter
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pschelbert

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Re: Volume Control and DSD
« Reply #19 on: July 26, 2018, 06:43:58 am »

This is a problem of the nonlinearity of the ear.
It is well known effect since ca. the 1930 (Flechter-Munson) that the frequency response of the ear is SPL-level dependent, thats why there is loudness correction.
It has nothing to do with the resolution of the signal or influence of volume control. The effect you will have as you noted if you have a super-duper precise volume control or not.

To get rid of that phenomen, exchange of the ears is needed :) which is rather difficult :)
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Hendrik

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Re: Volume Control and DSD
« Reply #20 on: July 26, 2018, 06:50:57 am »

Actually Media Center has a feature to change the frequency response of the signal to adapt to those ear changes, its called "Loudness", but requires proper calibration of a reference volume level to work, and no outside volume change beyond what you calibrated for (ie. need to use Internal Volume).

Of course none of this works with DSD.
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pschelbert

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Re: Volume Control and DSD
« Reply #21 on: July 26, 2018, 07:06:56 am »

good point, so anybody can test easily.

I use loudness correction in acourateconvolver, same principle, its an added piece of software running in conjunction with JRiver.
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michael123

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Re: Volume Control and DSD
« Reply #22 on: July 26, 2018, 09:03:10 am »

This is a problem of the nonlinearity of the ear.
It is well known effect since ca. the 1930 (Flechter-Munson) that the frequency response of the ear is SPL-level dependent, thats why there is loudness correction.
It has nothing to do with the resolution of the signal or influence of volume control. The effect you will have as you noted if you have a super-duper precise volume control or not.

To get rid of that phenomen, exchange of the ears is needed :) which is rather difficult :)

This phenomenon is fixed with the high-quality analogue preamp   ;D

[ Yes, I know how Flechter-Munson graph looks like, I said reducing the volume in JRiver from 100 to 93 is safe; down to 88 already will deteriorate the sound.. in contrary to analogue chain ]
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pschelbert

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Re: Volume Control and DSD
« Reply #23 on: July 26, 2018, 10:12:12 am »

no, as we have here discussed in detail. You can lower over digital at least 50dB and still have high resolution.
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michael123

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Re: Volume Control and DSD
« Reply #24 on: July 26, 2018, 01:02:20 pm »

no, as we have here discussed in detail. You can lower over digital at least 50dB and still have high resolution.

Are you also listening sometimes. or just discussing?  ;D
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maxuell72

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Re: Volume Control and DSD
« Reply #25 on: February 27, 2021, 07:50:08 am »

By my ears i've tried dsd converting, digital volume control and some other tweaks on JRiver and my listenings tell me the best way is no file converting at all, if possible no dsp effect. Computer/JRiver to dac and direct connection to job power amp with an analogue volume button control works best in resolution and more natural sound.  Didn't like converting neither digital volume. My Marantz dac has volume control but that damage the sound too, that's why i put direct connection to the job
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