DSP - does it defeat the object of expensive analogue sources?

[babysnake]

Hi

I currently have a pair of active speakers where the crossover is implemented in a DSP unit that also does DRC

Necessarily therefore this sits between my DAC and my pre

Hence the analogue output from my relatively expensive DAC goes through another AD-DA process

So I'm thinking, am I "just" listening to the DAC in the crossover?

And if so, is there any point spending money on analogue sources of whatever flavour if there's any sort of downstream DSP?

And if I decide to get the DRC done prior to the DAC (using a digital in/digital out strategy), where does that leave me with the active crossover in terms of non-DSP options? (I've read elsewhere on this site detailed arguments that linear phase/time coherent/time aligned crossovers are the most desirable, but apparently only practical with DSP in an active setup!)

I'd be interested in people's views

 

[andreasmaaan]

Hi

I currently have a pair of active speakers where the crossover is implemented in a DSP unit that also does DRC

Necessarily therefore this sits between my DAC and my pre

Hence the analogue output from my relatively expensive DAC goes through another AD-DA process

So I'm thinking, am I "just" listening to the DAC in the crossover?

And if so, is there any point spending money on analogue sources of whatever flavour if there's any sort of downstream DSP?

And if I decide to get the DRC done prior to the DAC (using a digital in/digital out strategy), where does that leave me with the active crossover in terms of non-DSP options? (I've read elsewhere on this site detailed arguments that linear phase/time coherent/time aligned crossovers are the most desirable, but apparently only practical with DSP in an active setup!)

I'd be interested in people's views

Good questions

At each stage in your system there will be distortion introduced. This will first occur with your DAC source, then again with the speakers' ADCs, then again with their DACs, and then finally of course with the speakers' amps and drivers.

In terms of how much distortion each stage introduces - and of course this depends on the equipment - by far the most distortion will be introduced by the speaker drivers. Next most will likely be introduced by the amps (although probably at least an order of magnitude less), then less again (probably also an order of magnitude less) by each DA/AD stage.

So yes, doing a DA-AD-DA conversion as you are now is suboptimal, although probably still not significant in relation to total system distortion (with the caveat that of course not all distortion is equal in terms of audibility).

What other options do you have? Do your speakers accept digital inputs of any kind?

In fact, maybe you could run through what all your components are?

 

[babysnake]

Thanks for the input

My setup is as follows:

Source is a home built, passive cooled, low power Linux based Roon endpoint with separate Teddy Pardo PSUs for the main board and SotM USB card

This outputs over USB to Chord Blu2/DAC, then analogue to an Illusonic IAP4 that does the DRC and crossovers, thence to x2 Sanders Magtech amps. Speakers are Sanders Model 10 electrostatic/transmission line hybrids (no digital in)

Balanced transformer on the mains and a LessLoss bespoke x6 power distribution block

I have run this over and over in my mind and my options, if I want to keep it all analogue after the DAC, are limited I think

Something like a DEQX pre DAC to do the DRC, then a Marchand XM44 seems to be the only option I can find to do the crossovers. Whilst I don't for a second doubt they are a quality piece of kit, I am unsure as to whether in terms of simply being a crossover they will outperform the DSP in the Illusonic

Unfortunately it's quite an expensive test to run and may leave me with some niche, redundant kit !!

 

[Purité Audio]

Just sell the Chord, and go USB direct into the Illusonic.
Keith

 

[andreasmaaan]

Just sell the Chord, and go USB direct into the Illusonic.
Keith

100% agree. The Chord DAC and the ADC on the IAP4 probably aren't doing much if any audible damage, but there's absolutely no reason for them to be in the chain.

 

[babysnake]

Hi Keith

That was where I was before I demo'ed the Chord

However, there's no doubt in my mind that the sound is significantly better (let's say I much prefer it) now than before. PRAT in particular are exceptional in my view, as is imaging (although give their non-curved ESL panels the sweet spot is fairly small)

You could argue, in that case just leave it if it's so good, and I am very conscious of that

But I wouldn't be the audiophile upgrade addict I am if I didn't constantly strive to tinker

 

[babysnake]

The Chord DAC and the ADC on the IAP4 probably aren't doing much if any audible damage

If that's likely the case, and the IAP is practically (if not necessarily theoretically) audibly transparent, then I will probably leave well alone

I'll have to learn not to scratch this particular itch

 

[Purité Audio]

You need to compare the chord and Illusonic unsighted, unless the Chord has some extraordinary recon filter there will not be an audible difference.
Keih

 

[babysnake]

There's lots and lots of stuff around about how Rob Watt's DAC works (FPGA, bespoke coded recon filter, >1m taps etc etc) and I confess to being a bit of a fan
Nonetheless although difficult to do completely unsighted I can do an A/B reasonably easily (second USB cable then just switch source on the IAP) and I will do so over the weekend if work allows. Certainly next week if not

 

[andreasmaaan]

There's lots and lots of stuff around about how Rob Watt's DAC works (FPGA, bespoke coded recon filter, >1m taps etc etc) and I confess to being a bit of a fan
Nonetheless although difficult to do completely unsighted I can do an A/B reasonably easily (second USB cable then just switch source on the IAP) and I will do so over the weekend if work allows. Certainly next week if not

Rob Watts' "upscaling" and digital filtering theories are nonsense

Seriously though, I think I'd misunderstood what the Chord was doing.

IIUC, it's a "digital upscaler" so it is basically taking a USB input, upsampling according to Rob Watts' special formula, and on-sending a digital signal to the IAP4. Is that correct?

If that's the case, my post #5 is incorrect (I was thinking of your Chord as a DAC at that point).

 

[babysnake]

No the Chord Blu2 does the 'upscaling' from the USB and this then goes to a Chord DAVE (admittedly stoopid name!) via dual BNC 75ohm cables, and this does the actual DAC bit (with Rob's 'special sauce' filter) then analogue out from the DAVE to the analog in of the IAP

Very sorry if I was unclear before

As an aside I do enjoy discussions about DACs and the wildly different technical solutions the various companies employ

R2R? DeltaSigma? FPGA? Actual soldered on resistors!?

I mean it's all just maths right???

 

[andreasmaaan]

No the Chord Blu2 does the 'upscaling' from the USB and this then goes to a Chord DAVE (admittedly stoopid name!) via dual BNC 75ohm cables, and this does the actual DAC bit (with Rob's 'special sauce' filter) then analogue out from the DAVE to the analog in of the IAP

Very sorry if I was unclear before

As an aside I do enjoy discussions about DACs and the wildly different technical solutions the various companies employ

R2R? DeltaSigma? FPGA? Actual soldered on resistors!?

I mean it's all just maths right???

Ok I see In that case I stand by post #5, there's no point introducing an additional DA/AD step in your chain... unless you think it changes the sound and you like the change - but in that case you should take @Purité Audio's advice and confirm that you can actually hear the change under controlled conditions.

My view on DAC architecture FWIW is that any number of different means can produce the same audible result (transparency), although some means provide an easier and more cost-effective path than others...

 

[babysnake]

My view on DAC architecture FWIW is that any number of different means can produce the same audible result (transparency), although some means provide an easier and more cost-effective path than others...

Very fair point

... in that case you should take @Purité Audio's advice and confirm that you can actually hear the change under controlled conditions....

I will certainly get onto that and feedback the results

I'm grateful for all the input

 

[Cosmik]

I think it's mainly psychological - and I am prey to it, too. My system is digital without any resampling as far as the DAC. If I had an extra DA-AD stage in there it would bother me. I would *know* that I couldn't possibly hear its presence, but it would bother me anyway!

 

[babysnake]

I would *know* that I couldn't possibly hear its presence, but it would bother me anyway!

I don't know how all those guys out there with top end turntables plugged into active speakers cope with all the uncertainty

 

[andreasmaaan]

I've also become more comfortable with AD/DA stages recently, mostly as a result of listening to loopback recordings and comparing them to the originals - clearly, with a lot of not particularly expensive equipment available today there is not an audible difference.

Like @Cosmik however, I think I'd be irritated by the presence of an unnecessary AD/DA stage in my signal chain.

 

[SIY]

I think it's mainly psychological - and I am prey to it, too. My system is digital without any resampling as far as the DAC. If I had an extra DA-AD stage in there it would bother me. I would *know* that I couldn't possibly hear its presence, but it would bother me anyway!

Ditto. I might intellectually know that there's no sonic difference, but knowing the extra stuff is in there will cause my lyin' cheatin' brain to tell me otherwise. And for babysnake, it may well go in the opposite direction.

 

[babysnake]

And for babysnake, it may well go in the opposite direction.

Absolutely right

 

[FrantzM]

I've also become more comfortable with AD/DA stages recently, mostly as a result of listening to loopback recordings and comparing them to the originals - clearly, with a lot of not particularly expensive equipment available today there is not an audible difference.

Like @Cosmik however, I think I'd be irritated by the presence of an unnecessary AD/DA stage in my signal chain.

Me too...
Most of these AD to DA are transparent these days .. YEt .. something ..just something in the notion of multiple conversions takes hold in our minds and deter from fully enjoying our systems ... Bunch of OCD people

At the Original Poster. The Chord seems to be redundant in this scheme ... The "PRAT" you are perceiving is unlikely to hold under blind conditions.

 

[babysnake]

The Chord seems to be redundant in this scheme .

I shall endeavour to confirm, insofar as my Miltary Grade OCD allows!

If the AD-DA is effectively transparent, as you suggest and I hope, then I will be comparing the Chord plus cables to the IAP in terms of their DAC performance alone, which will be interesting to say the least