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Digital vs. analogue volume control for digital monitors

thesky555, modified 6 Years ago.

Digital vs. analogue volume control for digital monitors

Padawan Posts: 48 Join Date: 1/26/15 Recent Posts
I’m preparing for the arrival of my 8351As. They accept both a digital signal and an analogue signal.

My dealer says I’ll get the best result by feeding them an analogue signal, because I can then adjust the volume in the analogue domain, which doesn’t reduce the bit depth of the signal, as any digital volume control will do. But I’d like a second opinion on this.

Basically, I have these two options:

A: Send digital signal directly to the monitor. The volume control will then be handled in the digital domain, either inside my computer or by the GLM inside the monitor.

B: Convert the digital signal from my computer to analogue -> Control volume with an old-fashioned analogue pre-amp -> use analogue input on the monitor, after which the signal will be converted back to digital inside the monitor.

Does anybody have experiences with the audio quality differences between these two approaches?
Will I be able to hear the difference?
If I had to guess, I would imagine that the all-digital approach might retain more attack, but be less smooth sounding, or perhaps a bit blurry due to the need for more dither. And that the analogue approach might introduce slight changes to the overall tone (which would be of no importance because they would be corrected by GLM.) But I have no experience with this.

I’m aware that it must be of greatest importance which kind of DAC and analogue volume control I use. There are €10,000+ DACs out there.
At the moment I’m using a Benchmark DAC1 PRE, which is both my DAC and my volume control/pre-amp. The music I listen to is 16-bit standard CD quality upsampled to 24-bit in my computer.

It must also be of great importance which analogue-to-digital converter the Genelec 83xx-series uses. I haven't been able to find any information about chipsets, shielding, dedicated power supplies, and all that technical stuff; nor tests comparing the quality of the two inputs.

Thank you for any help.
digipete, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 99 Join Date: 6/18/11 Recent Posts
Congratulations on the 8351's!

I usually run my 8260's at -40dB through GLM and I have always been blown away by the effortless and naturally detailed sound.
Running all digital cuts all the usual losses and colorations from the signal chain - isn't that is the whole point?

I have never considered using a DAC with Genelcs, so I can't tell you how pristine a DAC you would need.
Then again: I thrust the professionals at Genelec over the amateurs and audiophools.
I would probably fire that dealer !!!

For perspective, you can attenuate more than -45dB on the extra zeroes that you just put in from 16 -> 24 bit.
1038, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Jedi Master Posts: 340 Join Date: 4/6/09 Recent Posts
I happily always demo 8200's using GLM as a digital volume control...

The thing that always amazes me is the people who endlessly complain about digital volume control never discuss the negatives of analog volume control....

We are also a Bricasti Distributor, it is interesting talking to Brian from Bricasti, originally they were dead against digital volume control, it was disabled in their M1 DAC, now a few years down the track Brian mainly demonstrates only using digital volume control.... The compromises involved in analog attenuation are real and audible, yet there is almost no discussion about it, it is just the usual forum heros who know everything and don't want to consider any other compromise...

I'd say choose your input based upon your needs rather than from any other aspect.
thesky555, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 48 Join Date: 1/26/15 Recent Posts
Thank you, everybody!

I’ll do some experimentation on my own in the coming months and get back to you.

If anybody else has thoughts or experiences with this I’ll be all ears.
joerggermany, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 36 Join Date: 12/23/13 Recent Posts
...
If I had to guess, I would imagine that the all-digital approach might retain more attack, but be less smooth sounding...
At the moment I’m using a Benchmark DAC1 PRE, which is both my DAC and my volume control/pre-amp. The music I listen to is 16-bit standard CD quality upsampled to 24-bit in my computer.


Thank you for any help.


You are right. But the Difference is very very small. If you have a digital chain, use it. But I would not
use oversampling the 16Bit in your PC. Let it 16 bit, so the Genelec with it's internal 24Bit processing
can do the rest.

Joerg
thesky555, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 48 Join Date: 1/26/15 Recent Posts
Aha! Interesting, Joerg. I did not know this.
colombo-riccardo, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Youngling Posts: 24 Join Date: 4/19/09 Recent Posts

You are right. But the Difference is very very small. If you have a digital chain, use it. But I would not
use oversampling the 16Bit in your PC. Let it 16 bit, so the Genelec with it's internal 24Bit processing
can do the rest.

Joerg


i have a question :

why The Genelec AD9200A converter outputs AES3 format with always 24 bit word length and 192 kHz sample rate ?

so that for example if i play 16 bit and 44.1 kHz then with an external D/A/D conversion i send always 24 bit and 192 kHz to the Genelec digital loudspeaker
thesky555, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 48 Join Date: 1/26/15 Recent Posts
Hey Colombo,
Interesting question. We know so little about the whole digital side to our monitors. It would be great if Genelec would disclose more of their thoughts behind the choices they've made.
Perhaps, this question merits it's own thread.
digipete, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Padawan Posts: 99 Join Date: 6/18/11 Recent Posts
Colombo

The Genelec AD9200A converter does NOT take digital inputs at all.

If you have a S/PDIF output from say a CD player, you can buy a small converter from Neutrix that converts the signal to AES3.
The protocol is the same, but impedance is slightly different, that is all.
ilkka-rissanen, modified 6 Years ago.

Re: Digital vs. analogue volume control for digital monitors

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi all,

AD9200A is an analog-to-digital converter. One of the targets in the design has been to ensure that the AD conversion stage does not limit the signal in any way. This is the reason why AD9200A uses the highest possible sample rate (192 kHz) and the highest possible word length (24 bits) giving the highest possible audio bandwidth (about 100 kHz) and maximum resolution.

The audio signal played back to Genelec monitors could arise from any source. Your example of a standard CD quality source is one example. No matter what the source, Genelec AD9200A avoids limiting the signal quality.