Contemplating mini-DSP

[rfj1862]

Not getting much help from miniDSP or their forum (although I admit I'm impatient!) I'm contemplating using miniDSP, but I can't figure out which product is appropriate for my particular application.

 

I am playing 2-channel stereo through my computer, toslink out to a DAC and then to a preamp. The preamp is driving a 2-channel McIntosh tube amp and single powered sub, using a Y splitter as there is no dedicated sub output. Ultimately I'd like to run dual subwoofers, non-summed.

 

Which product is appropriate for this situation?

 

Thanks,

 

John

[edn4x4]

I bought this:

https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd

 

I have a dedicated 2.2 system and this has worked great.

Read the application notes:

https://www.minidsp.com/component/content/article?id=282

for sub integration.

A couple weeks ago, they announced that you could upgrade the firmware with Dirac

https://www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24

 

I just set up Dirac last weekend, and so far have been very impressed.

[rfj1862]

I bought this:

https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd

 

I have a dedicated 2.2 system and this has worked great.

Read the application notes:

https://www.minidsp.com/component/content/article?id=282

for sub integration.

A couple weeks ago, they announced that you could upgrade the firmware with Dirac

https://www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24

 

I just set up Dirac last weekend, and so far have been very impressed.

 

Thank you for your reply, it is very helpful--at least now I know where to get started in my research.

 

I'm probably just getting confused because I just started to think about this and to my molecular biologist brain this is all a little mind boggling, but does Dirac offer the ability to create my own crossovers between the subs and mains? Also I may be missing something but is there a comprehensive user manual for the 2x4 anywhere on their site?

[edn4x4]

Yes - you can create your own crossovers as I have as well.

It is all here:

https://www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24

 

Read about the subwoofer integration:

https://www.minidsp.com/applications/digital-room-correction/ddrc-24-for-2-1-system

and the comprehensive manual is on that page as well:

https://www.minidsp.com/images/documents/miniDSP%20DDRC-24%20User%20Manual.pdf

 

Make sure to gain match your subs first.

[jamesg11]

Yes, very useful.

 

Thoughts?? - re 2.2 setup - on 'trying' to better mesh 2x REL305 subs with front speakers by only dsp-ing the subs ie. sub outs on preamp plus .1LFE outs on Oppo105 are thru dsp, but not front speakers driven by power amp. This is for AV purposes, eg playing a bluray.

Chances of improving things? Is the delay - which clearly can't be adjusted other than by dsp - likely to be the killer downside? What else ...?

[Keith_W]

Hi James, the problem with the MiniDSP is that it will redigitize any analog signal you send to it and use rather poor quality DAC's (SHARC) in its output stage. The only exception is if you buy the MiniDSP DDRC-22D, which accepts digital input and has a digital output. Then you have to buy another DAC.

 

I would suggest that your computer is ALREADY capable of generating an active crossover without the need to buy a MiniDSP. What you need is a multichannel DAC and the appropriate software. I use Acourate.

 

I am in Melbourne as well, and I have implemented this. Drop me a PM and you can come and visit, and I will explain the setup. I am in Camberwell.

[rfj1862]

Hi James, the problem with the MiniDSP is that it will redigitize any analog signal you send to it and use rather poor quality DAC's (SHARC) in its output stage. The only exception is if you buy the MiniDSP DDRC-22D, which accepts digital input and has a digital output. Then you have to buy another DAC.

 

I would suggest that your computer is ALREADY capable of generating an active crossover without the need to buy a MiniDSP. What you need is a multichannel DAC and the appropriate software. I use Acourate.

 

I am in Melbourne as well, and I have implemented this. Drop me a PM and you can come and visit, and I will explain the setup. I am in Camberwell.

 

Acourate is highly interesting, BUT the reason I was considering an external box solution (I ended going with DEQX) is that as far as I can tell it is impossible to output Spotify through JRiver. Or am I mistaken in this assumption? Given that I use Spotify extensively for new music discovery, I wouldn't want that to be an uncorrected source.

[Keith_W]

I don't use Spotify. Does it have ASIO support? From a quick Google, I see that there is third party support for ASIO in Spotify. If you are able to output ASIO, you can use JRiver for convolution. Or Acourate Convolver.

[rfj1862]

I don't use Spotify. Does it have ASIO support? From a quick Google, I see that there is third party support for ASIO in Spotify. If you are able to output ASIO, you can use JRiver for convolution. Or Acourate Convolver.

 

Huh, interesting. I wonder if that is sanctioned by Spotify or not? They have been notoriously difficult about keeping users inside the Spotify interface. Just thinking they could get shut down which would leave me SOL. But if it does work that's very exciting, I really wanted to play with Acourate.

[Keith_W]

Hmmm, I have a few thoughts. I hope you don't mind.

 

1. Spotify maxes out at 320kbps MP3. Not exactly the best quality.

 

2. You should be using ASIO. Always.

 

3. I hope you are feeding digital to your DEQX. Feeding it an analog signal from your DAC, then running it through its ADC and then another DAC, is really bad.

[rfj1862]

Hmmm, I have a few thoughts. I hope you don't mind.

 

1. Spotify maxes out at 320kbps MP3. Not exactly the best quality.

 

2. You should be using ASIO. Always.

 

3. I hope you are feeding digital to your DEQX. Feeding it an analog signal from your DAC, then running it through its ADC and then another DAC, is really bad.

 

1. It's good enough for background music (which I listen to 12 hours a day while I'm working) and for exploration; I listen to music seriously for about an hour a day and then it's time to break out the high-res

2. Why ASIO always?

3. Unless I am confused by the DEQX manual, my outboard DAC is used "instead" of the internal DAC so only one digital-analog conversion is necessary. But you know I'm going to check that, the DEQX manual is not particularly well written, and definitely does not provide the level of detail I'd like (even though it is 180 pages long). So digital signal --> DEQX --> DAC --> Amplifier

[Keith_W]

Use ASIO to bypass the Windows mixer. Windows does all sorts of unspeakable things to your signal. ASIO ensures a direct line between your playback program and the output.

 

If you include a photo of how you have cabled your DEQX, I should be able to tell you if you have wired it up correctly.

 

To be honest, I don't think you need a DEQX. All you need is the software. And the software is much more powerful than the DEQX - it can be as powerful as your computer can handle. I can tell you that I have an i7-6700K, and I use it to perform 8 channels of convolution and upsample to DSD256. And all this at 64 bit floating point. Doing this almost maxes out my CPU load. My PC probably has several orders of magnitude more processing power than the DEQX. And once I add a CUDA enabled GPU, I will have even more power.

[rfj1862]

Interesting, you make me wish I lived in Australia so I could hang out at your place :-)

 

What you just said is gibberish to me right now (despite an extensive graduate level math education!), but I am learning quickly. I've plowed halfway through the Acoustics and Psychoacoustics textbook as a primer, hoping to finish it while on vacation.

 

I have the DEQX in place for one system, but you have certainly convinced me to make an attempt at a software-only solution for my other system. Plus I get to spend many happy hours learning. The DEQX is connected properly.

 

Do you have any recommendations for a small, quiet, high-quality, and decent looking computer that I can drop into my system as a home theater computer? It would also be nice 'cause I could run HBO GO etc through it instead of through g*ddamn Roku (which you may or may not be cursed with in Australia).

[Keith_W]

Well I have a graduate degree in a completely different field, and irrelevant to audio! I wish I had a maths or engineering degree, that would at least help me understand what I am doing at a deeper level. When I google something, I roll my eyes when equations come up. e.g. for years I have tried to understand the mathematical theory behind different crossover designs, and I have failed badly. At least you can do it.

 

Your HTPC can be as powerful as you want it to be. For a start, perhaps you could tell us what you want to do with it:

 

- single channel or multichannel? If so, how many channels?

- Do you need DSD?

- Are you planning to use your PC to upsample video? Up to 4K?

- Are you going to upsample PCM or DSD?

- Do you know how to build a PC?

- Do you want a compact case?

- Does the PC need to be silent?

 

I know that some people on this forum are minimalists. They believe that you should buy the minimum PC that you can get away with. Not me, I like plenty of overhead. The downside of this is that you then struggle with noise, heat, inadequate power supply, etc. How much of this are you prepared to put up with?