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Question about Volume Knobs on Amplifiers

post #1 of 31
Thread Starter 

Recently, I've been advised to keep the volume knob on my DAC on maximum because altering the knob would introduce some variables into the music. I am wondering if the same is true for amplifiers?

 

My setup is as follows: Computer - (USB) - > V800 DAC - (Balanced) - > Amplifier - (Balanced) -> Headphones.

 

In my case, I should adjust the volume via Windows/Itunes or Foobar and leave the knobs at maximum?

post #2 of 31

Typically the other way around is best.  Windows and Foobar change volume digitally; i.e., by throwing out some data.  Keep the digital controls at maximum and control volume with analog controls.

 

Analog volume controls generally sound best roughly half way, but do not worry about this.  They always sound better than digital.

 

Happy listening.

post #3 of 31
Thread Starter 

Thanks for the quick response. So what is the best volume to keep my itunes and windows while adjusting the analog controls? Maybe I'm interpreting this all too simply.

post #4 of 31

Place all computer/digital sliders all the way up.  Use the physical amplifier's volume control (analog) to change listening volume.

 

Simple is good, :)

post #5 of 31

In addition to Wapiti right statements, there are some software volume controls that exceed the 100% of the volume (VLC is an example of that). The volume has to be always at 0.0 dB, with no increase or decrease in gain. There are sofisticated dithered digital volume controls to make it supposedly "transparent" sounding though.

post #6 of 31
Quote:
Originally Posted by Beyerdynamico View Post

In addition to Wapiti right statements, there are some software volume controls that exceed the 100% of the volume (VLC is an example of that). The volume has to be always at 0.0 dB, with no increase or decrease in gain. There are sofisticated dithered digital volume controls to make it supposedly "transparent" sounding though.

    Quote:

Originally Posted by Wapiti View Post

Analog volume controls generally sound best roughly half way, but do not worry about this.  They always sound better than digital.


There are exceptions. For example, the uDAC-2 clips with a 0dB signal, and so digital volume should be turned down slightly. Other examples include any amp with serious channel balance issues. Low volumes on them could cause problems much more audible than the loss of dynamic range caused by digital volume control. ReplayGain is digital volume control, but it doesn't impact the sound. Digital attenuation in general doesn't impact the sound, unless the overall volume's turned high enough that the digital noise floor is audible.

 

I'd say as a general rule you don't want to attenuate by more than -20dB, but -10dB should be inaudible in most cases.


Edited by Head Injury - 10/20/11 at 9:53am
post #7 of 31
Quote:
Originally Posted by Head Injury View Post

    Quote:

There are exceptions. For example, the uDAC-2 clips with a 0dB signal, and so digital volume should be turned down slightly.


mmm.. That reminds me about the owner's manual from the Meier Corda 2move when I had it. Perhaps it has nothing to do with that though. It says something like portable players are recommended to have the volume at 70/80% when feeding the Corda amp, then you just use the analog volume control.

 

post #8 of 31
Quote:
Originally Posted by Head Injury View Post

    Quote:

There are exceptions. For example, the uDAC-2 clips with a 0dB signal, and so digital volume should be turned down slightly.


Interesting.  The DAC itself clips when fed a standard full-range digital datastream?  Bad design.  This should never happen.

 

Quote:

 

Originally Posted by Head Injury

Digital attenuation in general doesn't impact the sound, unless the overall volume's turned high enough that the digital noise floor is audible.

 

This is not quite true.  Digital volume controls work by removing bit-depth; i.e., actually removing data.  A little bit of this is relatively transparent, but a lot you will hear - the sound becomes dull, expressionless, lifeless. 

 

Quote:

Originally Posted by Beyerdynamico

. . . there are some software volume controls that exceed the 100% of the volume.

 

Excellent point.


Edited by Wapiti - 10/20/11 at 11:32am
post #9 of 31

Use an ASIO plugin for your music software, then you are assured of bit perfect stream to your DAC.

post #10 of 31

the "lost bits" heuristic is lame - if the bits that are "lost" are already deep in the analog electronic's noise there's no audible consequence - you need to know system gain structure, noise of all of the electronics to know if it is a real (audible) effect in your system

 

for 24 bit data it simply isn't true because the analog electrical noise in the DAC and amp are much higher than the lsb

 

in fact most sound processing today should be aware of 24 output DAC and even with 16 bit source deliver the top 24 bits of any processing

 

redithering would only be necessary if you have a 16 bit DAC - which are getting rather scarce

post #11 of 31
Quote:
Originally Posted by jcx View Post

the "lost bits" heuristic is lame - if the bits that are "lost" are already deep in the analog electronic's noise there's no audible consequence - you need to know system gain structure, noise of all of the electronics to know if it is a real (audible) effect in your system

 

for 24 bit data it simply isn't true because the analog electrical noise in the DAC and amp are much higher than the lsb

 

in fact most sound processing today should be aware of 24 output DAC and even with 16 bit source deliver the top 24 bits of any processing

 

redithering would only be necessary if you have a 16 bit DAC - which are getting rather scarce

 

No argument given the assumption the datastream is lossless 24-bit.  In fact, no DAC resolves more than 20 bits of data in any event. :)

 

In the real world, most listen to 16-bit, often compromised by compression to MP3 or similar.  A little bit of digital volume control will do no or little audible harm.  Leave the analog amp at full gain while using a digital volume control to listen at 30% (e.g.) and the sound is compromised.

post #12 of 31

Windows 7 and Vista both do volume calcs in 32 bit float, put out 24 bit resolution to HD chipsets - all that is shipping for a while now - this hi res output stream is independent of source depth - CD or mp3 streams would be treated the same

 

apparently there are SRC, default sample Rate bugs

 

but there is no meaningful "bit loss" from windows digital volume control since it will put out 24 bits if your hardware has the resolution - then the "lost bits" are way below any audio hardware's analog electronic noise


Edited by jcx - 10/21/11 at 12:41pm
post #13 of 31

I think you are getting stuck in the virtual world.  The query is whether it will sound better relying on a source's digital volume control for attenuation or the analog volume control on an amp.

 

Let's assume you want to listen at 25% volume, a common level.  The digital source, to attenuate by 75%, necessarily throws out a lot of bit-depth resolution - regardless of internal upsampling or bit-depth changes (neither of which create more or "better" data).  There is then the potential issue of feeding the amp an overly low level input and pushing the gain structure of the amp.

 

Leaving the digital volume control at 100%, feeding a full range signal to the amp, and using the analog volume control will result in better sound. 

 

Of course if you prefer the sound of a heavily attenuated digital volume control feeding a low level signal to an amp you should listen to this.  Most will prefer the sound of cleanest source/analog attenuation.

post #14 of 31
Thread Starter 

Thanks for all of your input! Especially Wapiti for dumbing things down for a novice like myself. As for software that use 120% volume like VLC, what must I do to ensure that "the volume has to be always at 0.0 dB, with no increase or decrease in gain?" Does that require fiddling with some equalizer on my sound card driver or simply lowering my windows volume to: 100/1.2 (83%)? 

 

Sorry for these sorts of questions. If I had more time to do the research, I would probably learn about these things from ground up. I already deal with amplifiers at my work as I'm in the electrophysiology research field, but I fully intend on learning about how they work once I'm done with my current obligations. 

post #15 of 31

rolleyes.gif rolleyes.gif rolleyes.gif  http://www.violectric.de/Pages/en/faq.php#V800 digital volume

 

Read this.

 

 

Then... Set your OS up for audio playback if you haven't done it yet. This is vital, imho.

 

In Windows, download the ASIO drivers so to bypass the crappy default digital mixer.

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