[Jazzman53]

Can someone recommend a digital in/out volume controller for my TV's optical/digital out?

I want to feed my TV's optical digital output directly into a digital input on my audio system's DSP/Crossover. The TV's digital out isn't volume controlled so I will need an interface to control the volume. 

Any suggestions?

Thanks,
Charlie

[WGH]

I'm curious to read the answers. I always thought reducing volume in the digital domain was achieved by reducing the bits, which also reduced the sound quality.

What other inputs does the DSP have?

[Jazzman53]

I'm curious to read the answers. I always thought reducing volume in the digital domain was achieved by reducing the bits, which also reduced the sound quality.

What other inputs does the DSP have?

16 bits equates to 96db and 24 bits equates to 144db. 

Halving the volume digitally uses 1 bit of resolution, and halving the volume via analog reduces the headroom above the noise floor, so neither is prefect. 

I no longer use an analog preamp in my system.  For music playback I stream volume-controlled digital out from a Logitech Transporter to a digital input on a DBX Driverack Venu 360 DSP/crossover.   My system (with subs) is 6-channel stereo.

This setup requires only a single D/A conversion in the signal path.  I just need a way to volume control the TV's digital out so I can play Youtube concerts through my audio system without going thru an analog preamp.

I have state of the art homebuilt hybrid ESL speakers with superb resolution, so I'm rather certain I would discern any audible degradation.  I've used both analog and digital volume control in my system and both sound really good but I prefer digital.  It sounds fabulous, and I'm not going back to analog volume control with multiple A/D & D/A conversions in the signal path.   

The DBX has both balanced analog XLR inputs and (2) AES digital inputs.  I want to feed the TV into the second digital input. 

I would only need volume-control but perhaps there are some inexpensive streamers that could serve this purpose. 

However, in most streamers the digital in is only there to allow using it as a stand-alone DAC, where the digital in is converted to analog out only (i.e. no pathway from digital in to digital out).  So, I would need to verify that whatever I use can volume-control a digital input and rout it to a digital output.
 
 

[Rusty Jefferson]

A dac/preamp/processor with multiple digital inputs is the obvious but expensive solution, of course. 32 bit volume is best, not 24 bit.  The Danville Signal processor is a great option. If your speakers are SOTA perhaps a front end upgrade is possible?

https://danvillesignal.com/dspnexus-dsp-audio-processor

[Jazzman53]

A dac/preamp/processor with multiple digital inputs is the obvious but expensive solution, of course. 32 bit volume is best, not 24 bit.  The Danville Signal processor is a great option. If your speakers are SOTA perhaps a front end upgrade is possible?

https://danvillesignal.com/dspnexus-dsp-audio-processor

I'm coming to believe that a simple digital volume control device doesn't exist, and cost is an issue, as I am living on a fixed income (old guy here). 

Correct me if I'm wrong but I recall reading somewhere that many or most digital preamps would internally upsample a 24bit input to 32 bits to do the volume control. 

In any case, I/m not expecting hi-resolution from a Youtube video but my system would have to sound better than the TV speakers.  My Logitech Transporter volume-controls it's digital stream to both analog and digital outs, and it also has a digital input but the digital in goes thru its DAC to an analog output (not what I need). 

I may be out of luck finding a cheap solution here...

[WGH]

PLAN A

I have a germ of an idea but no way to test it out, that's your weekend project. I stream movies and videos from a computer via HDMI to a surround processor. I use the free VLC Media Player, it plays any format.

"VLC is a free and open source cross-platform multimedia player and framework that plays most multimedia files as well as DVDs, Audio CDs, VCDs, and various streaming protocols."


VLC Media Player has a volume control. Since the streaming and video input is digital and the output is digital (HDMI) I will assume the volume stays the digital domain. VLC can control the HDMI digital out volume!

3 Useful Tips on Playing and Saving YouTube Videos with VLC Media Player
https://videoconverter.wondershare.com/vlc/how-to-play-youtube-videos-in-vlc-media-player.html


Next you will need 4 items: a computer with HDMI out, a TV with HDMI input, a HDMI to Optical Audio Out Splitter and a wireless mouse. The mouse scroll wheel controls the volume from your easy chair.

Downloaded music videos, movies and PBS streaming nature programs will now come alive too.

UPDATE: NO YOUTUBE AUDIO

Well that sucks. Trying to stream music using VLC Media Player from YouTube was a total failure. The stream would not open, all I got was an error. Movies over my home network work fine but the on-screen volume slider doesn't lower the volume. The volume does change when I use my computer speakers so the slider only works with analog output.


SUCCESS!

I did discover that playing YouTube music using the Firefox browser works wonderfully and the YouTube volume slider works in the digital domain over HDMI. No messing around with VLC Media Player needed.

[WGH]

PLAN B

Pros: User friendly; TV remains the source; will probably sound just as good or better than optical-in to DBX.

Cons: Price


The Van Alstine DVA Digital Preamp has optical in and balanced XLR outputs. Yes the digital is converted to analog but I have heard the DVA Digital preamp in two systems: mine and a friend's, the sound is very, very clean and can't be faulted.

Larry likes the AVA DVA Digital preamp too
My Review of the DVA Digital preamp//DAC
https://www.audiocircle.com/index.php?topic=190241.0



https://avahifi.com/collections/digital-audio/products/dva-digital-preamplifier

There is a used DVA Digital preamp on the AVA site for $2200.
Try out the digital preamp for 30 days, all it will cost is shipping.

[richidoo]

You're smart  so this might be worth investigating for you - roll your own VC with RPi and a DSP i/o hat.
The DSP engine is completely programmable, but a volume control widget is preconfigured for easy use.

https://thepihut.com/products/hifiberry-dac-dsp
https://www.hifiberry.com/docs/data-sheets/datasheet-dac-dsp/
https://www.hifiberry.com/docs/software/dsp-profile-example/

[AVnerdguy]

A Raspberry Pi might be the least expensive option. Also this thing but I have no knowledge of how it sounds or ease of operation.
CYP DCT-39

Audiophonics Optical Coaxial SPDIF Upsampler with Volume Control

CYP DCT-39 allows to oversample a Coaxial or Optical source signal in 24bit 192kHz. The digital audio processor uses a DSP rather than a software process to limit distortion. The converted source signal can be output simultaneously in Optical and Coaxial. Then simply connect the DCT-39 to an amplifier to enjoy your audio file in high definition. In addition, the audio processor supports DoP (DSD over PCM). The DCT-39 also includes a volume control and de-pop function, which reduces noise when connecting an audio source.

[WGH]

Poking around the Audiophonics web site I found a digital preamp that might just work with stereo RCA and Toslink optical inputs and outputs for only $121.68 before taxes, shipping, etc.
This little unit looks like the Swiss Army Knife of preamps.

ARYLIC BP50 Preamplifier DAC ES9023P Bluetooth 5.2 aptX HD aptX Adaptive 24bit 192kHz
https://www.audiophonics.fr/en/preamplifiers-volume-controllers/arylic-bp50-preamplifier-dac-es9023p-bluetooth-52-aptx-hd-aptx-adaptive-24bit-192khz-p-18385.html

[WGH]

We're getting really affordable now.

A computer or laptop streaming YouTube music. Volume controlled by the little YouTube slider (lower left). No video using this method.

A USB to Toslink S/PDIF Converter for $20 from Amazon. I have no way to beta test this idea,

Maybe YouTube on your TV has a volume slider, then you don't need to buy anything if it works like a computer.

[Jazzman53]

We're getting really affordable now.

A computer or laptop streaming YouTube music. Volume controlled by the little YouTube slider (lower left). No video using this method.

A USB to Toslink S/PDIF Converter for $20 from Amazon. I have no way to beta test this idea,

Maybe YouTube on your TV has a volume slider, then you don't need to buy anything if it works like a computer.

Your response prompted a solution for me:

I'm feeling pretty much like an idiot at the moment for not seeing the obvious from the beginning.

When I'm playing music on my system, I set the DSP/Crossover input gain to full and control the volume upstream, using my Logitech Transporter streamer/digital preamp's Ipad control App, which is convenient and makes perfect sense.

While I could have routed the TV audio through the Transporter and controlled the volume there, that would have put multiple AD/DA conversions in signal path, which I didn't want to accept.

However, I completely overlooked the fact that my DBX has additional AES inputs with gain controls.

My TV has an optical audio out and the DBX has AES digital inputs so all I have to do is purchase a $20 Optical-to-AES adaptor to connect the TV into the DBX, and then control volume there using the input gain fader. Then I can play Youtubes from the TV or music from the Transporter by merely selecting the appropriate input on the DBX iPad App.

Problem solved... thanks for the tip!

[WGH]

Problem solved... thanks for the tip!

 

Something to listen to after your dongle arrives, excellent "you are there"stereo. Available on YouTube of course - welcome to the future:
https://youtu.be/lmWFrMq3qNY

I Think We're All Bozos On This Bus - The Firesign Theater