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Optimizing Digital Volume Control

Hi,

First I would like to state that I am relatively new to audiophilia (sounds like a disease), however I have a relatively good engineering background.

Presently I am using a traditional CD->DAC->pre->power->speakers setup. I am using a Hegel HD20 DAC that has a digital volume control feature. I recently noticed that without the pre (ARC LS2) in the chain, using the DAC for volume control, I get better results.

Since the DAC is 24b, having a -140db noise floor (close to 144db theoretical limit) this makes sense to me. Since a CD, having 16bit resolution, supports a theoretical maximum of 96db (practical implementation are below 90db). So s properly designed digital attenuation of over 50db (probably in this case over 60db) should not degrade the sound.

Now to my question, assuming a computer as the source, followed by a 24b DAC that doesn't support volume control, one can in theory achieve the same results if the computer converts the 16b original data to 24b and then apply digital volume control. In this case the computer should output a 24b signal to the DAC.

Does anyone know if this is something that a JRiver or Foobar solution is capable of doing? or in general, does anyone know how volume control would work using JRiver or Foobar?

Thank you in advance for your attention.
oferi

Showing 5 responses by edorr

edorr
714 posts
 
That is how Jriver works. You can read up on this online.
edorr
714 posts
 
I was firmly into the no preamp camp (used the volume control of my msb dac) until I tried the arc ref5se. No comparison - preamp is back. Not cheap - extra set of interconnects, power cord - the works. Bottom line: forget theory and dogma and trust your ears. In my experience, only very high grade preamps will beat no preamp. But they do.
edorr
714 posts
 
Oferi, with all due respect, I came to the same conclusion with the caliber preamp you tried. You need to move way up the preamp foodchain to get an improvement over no preamp. So no preamp offers superior price/performance any day of the week, and will be the best architecture for the majority of systems.

However, in my experience, if you want the best of the best, you need to pull out the checkbook bigtime and get a VERY good pre. Nine out of ten "ultra high end" guys (six figure systems and up), will confirm this.
edorr
714 posts
 
Steve, this is the theory. As I mentioned, nine out of ten of the guys on whatsbestforum with six figure systems end up adding a preamp to their DAC. They can't be all tone deaf and/or suckers. As Denon mentioned, you need to spend $20K (and up) to get the desired result, which they do.
edorr
714 posts
 
Steve, bad analogy. iPod users use the stock earphones because they sound "good enough" and they don't feel the need to spend the money to get better sound.

Uber-audiophiles have exactly the opposite motivation; no preamp does NOT sound enough, and they are willing to spend the price of a mid size sedan to get better sound.

This is typically a highly informed decision, based on extensive auditioning of gear. I personally went through a few preamps that did not make the cut, a digital and analog volume control on a DAC and ended up settling for the arc ref5SE with transparent reference ICs and shunyata python zitron powercable (I threw in three stillpoint ultra's under the preamp for good measure as well).

I bought the preamp used with the intent of immediately reselling it if it did not improve SQ over the analog VC of my DAC (like I did with the Pass Labs XP-10 and the EMM Labs Switchman - resold within 48hours). If someone expertly "informed" me I was in fact getting worse sound because of some engineering principle, I would have still trusted my ears and kept the preamp.
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