Article: The Value Proposition in Computer Audio: Entering Multichannel at the Ground Floor

[Kal Rubinson]

On 9/18/2020 at 2:18 PM, Bill Brown said:

(I keep hoping KR will dip his toes into it, though I know in the past he wasn't impressed).

Sorry.  I do not have any need for upmixing for anything more than ambiance recovery and, for that, I can use Auro2D or Auro3D.  

[Kal Rubinson]

5 hours ago, bluesman said:

As I recall, the AuroMatic 2D plugin lists for $600 per the B&H website.

It came "free" with my Marantz AV8805.

[Kal Rubinson]

1 hour ago, jrobbins50 said:

What do you do with Auro, and is it also in my AV-8802A?

I just switch it on for many stereo sources.  It is subtle but effective in opening up the soundstage and disassociating it from the L/R speakers.  There is an Auro upgrade for the  AV8802a: 

Auro-3D

This mode uses an Auro-3D decoder to create three-dimensional audio output using the Height Channel. It is ideal for playback of signals encoded as Auro-3D with a Height Channel. If signals not encoded as Auro-3D are input, an Upmixer called the Auro-Matic is used to create highly realistic three-dimensional audio output.  

 

1 hour ago, jrobbins50 said:

Have you tried the above referenced ESI Gigaport ex MCH DAC yet?

I have not.

[Kal Rubinson]

7 hours ago, jrobbins50 said:

@Kal Rubinson, what do you use for a height channel and where do you place it?  And could you offer a track or album that you believe best demonstrates the effect you note. Thanks. JCR 

I do not at the moment.  Right now, I am using Auro2d since I have only the 5 base level speakers.  I did experiment with Auro3d when I had a 5.1.4 system temporarily.  At that time, I added 4 KEF R8a ATMOS speakers, one on top of each FL, FR,SL and SR speaker.

 

However, since my acquisition of a NAD M28, I have decided to reinstate that configuration but the is currently in progress. 

[Kal Rubinson]

Delete this.

[Kal Rubinson]

3 hours ago, jrobbins50 said:

So, Auro3d requires no further speakers or amps. Let me understand the arrangement, @Kal Rubinson.

No.  3D requires speakers (and amps) above the horizontal listening plane.

3 hours ago, jrobbins50 said:

Can I turn Auro2d alone on for a single input of that sort?

It is possible that you can but there's no point to it with only 2 speakers.  It is meant to up-mix stereo to a more spacious soundfield and requires additional speakers in the horizontal listening plane.

[Kal Rubinson]

29 minutes ago, jrobbins50 said:

 So, I’m unclear as to whether a 5.2 surround arrangement will work fine for Auro2d 

Sure.  You have more than just a stereo L/R pair to which you can expand.

30 minutes ago, jrobbins50 said:

I’m interested in your experience using the 7.1 analog inputs on the AV-8802A as to whether that input set can support Auro2d.

No.  You must use another input since the 7.1 analog inputs bypass all digital processing.  Even the stereo analog inputs would work but any of the digital ones would be better.

[Kal Rubinson]

27 minutes ago, jrobbins50 said:

Sorry, @Kal Rubinson, but I am now slightly confused.  I totally get that I can't use the 7.1 analog inputs for Auro-2d.  But, you reference using stereo analog inputs, which would imply a stereo output. 

1.  Yes, to use Auro-2D, you supply the Marantz with a stereo source input and it will output an Auro-2D 5.1 or 7.1 signal to your 5.1 or 7.1 speaker setup.

2.  You cannot use the 7.1 analog inputs because those are not digitized by the Marantz but the stereo analog inputs are!

30 minutes ago, jrobbins50 said:

Source stereo file on NAS or streaming from Tidal ---> Server for convolution and Roon playback ---> analog stereo input on Marantz, applying Auro-2d ---> 5.2 output to amps and subs

Seems right.

31 minutes ago, jrobbins50 said:

Put another way, does Auro-2d cause the Marantz to take the stereo input and create a surround environment with it?  If so, then a MCH DAC isn't even required, right?

Yes and yes,  Since the job of Auro-2D is to up-mix stereo to a pseudo-multichannel output, why would you feed it multichannel?

32 minutes ago, jrobbins50 said:

Since my Bel Canto streamer's 2-channel outputs are connected to the stereo analog inputs on the Marantz, it would just be a flick of the switch, so to speak, to enable Auro-2d for that input set and then the output from the Marantz would be 5.2? 

Indeed.

 

32 minutes ago, jrobbins50 said:

And would you, as I suggest above, apply convolution in Roon anyway before Auro-2d, or are they mutually exclusive sound processing arrangements?

It depends on what you are doing convolution for.  If you are doing it for speaker/room correction, I would not as I would let the Marantz Audyssey handle it.

 

[Kal Rubinson]

1 hour ago, jrobbins50 said:

So, are you suggesting that for this specific purpose — using Auro-2d in the Marantz — I should calibrate an Audyssey pro MCH filter for the Marantz and have convolution off in Roon?  Ugh, more work, but I believe I see your point. 

Yes.  The point is that, since you are sending only stereo to the Marantz, AudioLense can only EQ those 2 channels because the one's that Auro2D extracts are not accessible to it.  So, even though Audyssey is not as competent as AudioLense, it is better than no EQ.

1 hour ago, jrobbins50 said:

The Auro-2d upgrade is $199 and the Audyssey pro license is $150.  And then there is the time to install, learn and use Audyssey pro. Is Auro-2d worth that investment, in your opinion?

Hard for me to say.  Have you tried any of the up-mixing options that the Marantz has now to get a taste of what Auro-2D might do?

[Kal Rubinson]

Try the various Dolby and/or dts options.

[Kal Rubinson]

58 minutes ago, Bill Brown said:

Wow.  Your setup with a multi-channel DAC would be perfect for me to run Auro as a plug-in if they develop a VST or AU version (currently just AAX for Protools).......

I wish.

[Kal Rubinson]

2 hours ago, bluesman said:

Auro may not be accessible by digital input. 

It is.

2 hours ago, bluesman said:

If I were you, I'd connect your Bel Canto digitally to your Marantz and start listening to the various ambience syntheses available to you.  Once you see what they can do, you'll have a better idea of if and how much you like the concept.

Exactly.

2 hours ago, bluesman said:

I'm also confused about your Okto DAC8 Pro.  Why do you need it if you have a MC receiver?  I know of no advantage to driving the unbalanced analog inputs of the Marantz with an 8 channel balanced DAC.

It may be justified if one thinks that the d/a in the Okto is sufficiently superior to the d/a in the Marantz.

 

[Kal Rubinson]

20 minutes ago, bluesman said:

Almost all HT receivers convert analog input to digital before it reaches the DSP chips. They then run the processed digital signals through a DAC for analog output to the speakers.

This Marantz does not do this nor does mine.  There is no a/d nor, of course, an additional d/a with the 7.1 analog multichannel inputs, only with the stereo analog inputs.

[Kal Rubinson]

1 hour ago, bluesman said:

So the internal MC DSP simulations and ambience synthesis functions like Dolby are also non-functional on the analog MC inputs?  

Yes.

1 hour ago, bluesman said:

The only reason I can see for this would be the assumption that any and all DSP is being applied ahead of a DAC in a front end that has no analog power output stage

I do wonder about the reason for it but it is what I use to integrate my streamer and mch DAC with my multichannel prepro since I do all processing, including DiracLive, in software.

 

1 hour ago, bluesman said:

 If so, why would anyone buy (or, for that matter, try to sell) a $4k+ receiver to use as an analog amplifier in lieu of better amplifiers for the same money? 

Simple.  It allows the easy integration of a dedicated multichannel streamer/processor with a HT prepro that lets them share power amps and speakers.

 

1 hour ago, bluesman said:

You seem to be contradicting yourself with the statement that “[t]his Marantz does not do this nor does mine.  There is no a/d nor, of course, an additional d/a with the 7.1 analog multichannel inputs, only with the stereo analog inputs”.

OK.  Clumsy wording but you did get the point: 

 

1 hour ago, bluesman said:

These Marantzes do exactly this - but (as you tell us) it’s only on input through the stereo RCAs and not on the 7.1 analog inputs.

  

[Kal Rubinson]

52 minutes ago, bluesman said:

You say clearly in this quote that the Marantz will output an Auro-2D 5.1 or 7.1 signal "to your...speaker setup".  It can't do that without an amplifier, which led me (and perhaps others) to believe that the Marantz units in question are receivers.  I just looked at their specs, and they're clearly not receivers - they're (as you described them) "pre-pros".  Forgive me for not knowing this, but my series is focused on the value oriented audiophile.  A $4k+ HT preamp is not commonly thought of as being a value oriented audio device.  Until today, I was entirely unfamiliar with this genre except for the Emotiva 700.

Despite the context of your thread, I was responding to @jrobbins50 posts directly and I did understand that he was using a prepro.

53 minutes ago, bluesman said:

As the OP makes no mention at all of amplifiers or speakers in any of his multiple posts, ...................  So any sonic advantage of his DACs over those in the Marantz will be diluted or washed away by additional ADA conversions and the use of unbalanced 2 conductor analog interconnects.

To be sure.

54 minutes ago, bluesman said:

But if the Marantz AD & DA convertors are suboptimal, are there higher quality pre-pros that might obviate the desire for a separate DAC up front?

I have not been able to assess enough prepros to say anything general, so I have only anecdotes.  At one time, I would have suggested the Bryston SP3 but too much time has past to expect it to be as outstanding as it once was.  I have not tried the SP4 or the related Storm Audio prepros or, for that matter, any others in that class.  Of those that I have used, the only one that stands out to me is the Trinnov Altitude 32.