TOPIC: SHD vs DDRC-24

I purchased a DDRC24 a few months ago and have to say I’m delighted with the result, using Dirac Live 2 (I’ve yet to upgrade to version 3).. My audio (and video) sources are controlled by a Marantz AVR receiver and this in turn feeds the DDRC24 via the AVR pre outs, with a stereo pair of active speakers and a subwoofer at the end of the chain from the DDRC analogue outputs. The AVR controls the master volume for all modes of listening and viewing

Bearing in mind that the DDRC24 has a DAC sample rate of 48khz, I’m wondering whether the SHD, with its more powerful processor and higher sampling rate, would provide a noticeable improvement in audio quality? An SHD would give me the flexibility to reduce DAC/ADC conversions from 3 (using the DDRC24 in the chain) to just 1.

Although nice to have, the display of the SHD showing source selection and volume is not a deal breaker for me. Any thoughts?

I assume you are saying that the additional inputs on the SHD will allow you to get rid of the AVR and use the SHD for source selection / volume control? Or are you saying you want to use the digital output of the SHD directly in to your active monitors? Maybe both? Either way I think getting down the number of DACs to an absolute minimum is a worth while goal. That being said I am assuming your active monitors have a DAC / DSP in them which will probably limit the benefit of any upstream upgrades.

In terms of 48 kHz vs 96 kHz I honestly am a bit unsure how this would impact Dirac implementation but 96 kHz will certainly be subject to less high frequency warping than 48 kHz although this is really only an issue if you are making corrections above 10 kHz.

Michael

Bialymn wrote:
I'd not noticed the 48 kHz figure given for the DDRC-24 before, which I'm a bit surprised at give that the 2x4 HD works at 96 kHz. It might be worth contacting support just to double check there truly is a difference compared to the SHD here.

I have a 2X4HD which I upgraded to a DDRC and can confirm the DSP runs at 48 kHz after the upgrade.

Although the SHD and the DDRC-24 both use SHARC 21489 DSPs the SHD runs at 450 MHz and the DDRC runs at 400 MHz. It makes sense to me that something would need to give with the DDRC as other than the sample rate it pretty much has the same processing power as the SHD (4 channel output, 10 PEQ bands per channel, Dirac). From a Dirac perspective FIR filters will be much more efficient at a 48 kHz sample rate than 96 kHz which is especially important at low frequencies where many FIR taps are required.

Michael

Yes the DDRC24 has reduced sample rates as more of the processing is required for Dirac I think. The SHD manages to keep the rate at 96KHz (with Dirac) and measures significantly better in most areas as well as of course being much more flexible in usability.

Which brings me back to my original post - are the audio differences noticeable? If I purchased an SHD, I could set it up to take a digital feed (from my Sonos Connect), take SHD digital outputs 1&2 to my active speakers (which have high quality inbuilt DACs built in) and use analogue output 3 of the SHD to my subwoofer. I could then use either Sonos or SHD to control the volume of the streaming music.

My current setup (using DDRC24) routes the Sonos digital output to an AVR, then the AVR analogue pre outs into DDRC24, which then has analogue outputs 1,2,3 to active speakers and sub. Which means 3 digital conversions (and at 48kHz at the DDRC interface). I’m doing it this way purely for convenience as the AVR then controls all inputs and volume (all from a Logitech Harmony Elite remote, so super easy to use for rest of family). I’m also using the AVR as a home theatre setup sharing the front L&R speakers and sub.

The SHD is expensive in Europe (compared to DDRC) so I don’t want to buy one if there’s little to be gained in terms of audio quality (I know the usability / versatility would be far better though).

Bialymn wrote:
I’m not convinced. You’ll still want surround sound from the AVR for your TV and (guessing) blu-ray and games console right? Therefore you’ll already have a volume display. You can already stream with your Sonos which might be more user friendly than Volumio. I don’t like the idea of the back and forth DA - AD -DA but if you send the Sonos digital out to the DDRC24 digital in you’ve immediately deleted one of the conversions.

So for stereo why not Sonos -> DDRC24-> Active speaker’s
And for surround sound AVR analogue out to DDRC24 analogue inputs.

Only thing you’ll miss is volume display when listening to music. Do what I’ve done and get yourself a little VU meter. Feed it a signal from output 4 and although not perfect it gives a reasonable guide to volume level.

Thanks and yes, that’s what I’ll try next with the DDRC. I’ve routed everything through the AVR more for convenience and consistency, but I’ll try the more direct stereo set up as you suggest. I’d have to use the Sonos digital volume control and keep the DDRC fixed, as the DDRC volume affects all inputs (ie the unit doesn’t remember individual volume settings for each input). That means I couldn’t use my Logitech remote but that’s no big deal I guess.

But like for like, does the SHD offer a ‘better’ audio quality than DDRC with its higher spec, or is it all beyond what the average human ear can discern?

I hadn’t considered volume control. Hmm I don’t know your Sonos’s specs but as was pointed out to me on this forum, using a digital volume on your streamer could effect sound quality as you start loosing the least significant bits (I think that was right).

The DDRC24/SHD volume controls would probably be better. I wonder if you could reduce the gain on the outputs so even at Master Volume of 0db there’s no risk of you deafening yourself, then calibrate your AVR with MV at 0. When you are listening in surround sound mode you just increase volume on your Ddrc24 to MV0. Lack of display is obviously a pain here.

As for how do DDRC24 and SHD compare... good question(!) looking forward to someone who knows giving you an answer!!

asx77 wrote:
Bear in mind that some attenuation needs to be applied in the digital domain to provide the headroom for boost applied by Dirac Live, so a 0 dB master volume is not generally a good idea.

How well volume control works in the digital domain depends on the implementation. I don't think this should be viewed as a concern for the the 32 bit floating point DSP chips we're talking about here. Bear in mind that analogue volume control isn't perfect either - there are pros and cons here.

Ultrasonic wrote:
Hi, Yes but can the same not be achieved by reducing the output on each output channel by -10db?

Bialymn wrote:
In case it's of any interest I went from a 2x4 HD to an SHD and compared how they sounded with matched PEQ applied but not using Dirac Live. Switching between the two I thought the SHD sounded slightly more natural (less 'grainy'), most clearly to me on female vocals. This was a 'sighted' test though so I can't swear that expectation bias didn't play a role.

asx77 wrote:
You can. Sorry, looking back I realise I misread your post. As you'd raised concern about digital volume control I thought you were suggesting using 0 dB to avoid this.

(I shouldn't post tired!)

.

No probs and phew. Because I run my DDRC24 straight into power amps I’ve got MV 0 to be the loudest I’d want to go. I’ve done that by reducing the output channel gains. Was worried for a min I’d got it wrong.

I think in hindsight I probably should have gone straight for the SHD but now I have the DDRC24 I do wonder whether the upgrade would be a case of diminishing returns. Thinking of waiting until I can repurpose the DDRC... now what else could I use it for?!!

I’ll experiment a bit more with my DDRC as it can be connected in numerous ways in my audio chain. I actually do have access to on screen displays as I have the Wi-DG usb bridge thingy which means I can use the iOS app to adjust presets and volume etc.

It’s just that setting everything up through the AVR and using Logitech remote is so convenient - ‘one click’ switching between pure stereo audio and video/surround sound modes, and having the same volume control.

The DDRC and Dirac have been a revelation though, making my already great active speakers even better, tightening up the audio quality and taming the wild bass swings in my room. Piano music for example, is so much more realistic. I guess the SHD would be a law of diminishing returns - maybe a little ‘better’ but at a price (especially here in UK). It would be a no-brainier if I needed the on screen displays, but that’s not so important.