TOPIC:

I'm trying to decide between purchasing multiple 2x4HDs and multiple units of some other model, such as the 10x10HD.

Is it accurate to say that the 4x10HD and the 10x10HD all share the 8x8 board at their heart?

I see the 114db specs published on those pages for the chip, and I see that Neurochrome has published very good test results of the 4x10 here:
www.neurochrome.com/minidsp-4x10-hd/

I know that the 2x4HD has a much more capable DSP chip -- but can anyone (MiniDSP) speak to how the models compare in terms of SNR? or overall performance?

I feel like the 2x4HD has more emphasis towards Dirac / complex filtering rather than basic performance. Is there a tradeoff between purchasing the 2x4HD instead of the 4x10 -- other than channel count?

As far as I understand, the 4x10HD is just

- 2x8 kit
- DIGI-FP
- VOL-FP
- a box.

Hence 4 (2 digital + 2 analog inputs) x 10 (8 analog + 2 digital). Some differences:

The DSP chip in 2x8 kit is the SigmaDSP ADAU1445 whereas 2x4HD has SHARC ADSP21489. As you already mentioned, the SHARC processors is more powerful. For example, the 4x10HD can only do 6 parametric filters per channel whereas in 2x4HD has 10. Also you cannot do any linear phase finite impulse response (FIR) filtering with the SigmaDSP because that requires a convolution engine and lots of processing power.

The DAC/ADC codec chip in 2x4HD is AKM AK4626 with a pretty average performance (103dB dynamic range, 0.003% THD). The 2x8 kit uses the better performing Cirrus Logic CS42518 chip (114dB dynamic range, 0.001% THD). Whether or not you can actually tell the difference in a real listening test is another story. Apparently it is almost impossible to notice: www.tomshardware.com/reviews/high-end-pc-audio,3733.html

2x4HD can stream audio from USB (has an XMOS chip), but 4x10HD cannot.

2x4HD consumes maximum of 2.5 watts and 4x10HD consumes about 6 watts.

Then there's the cost. 2x4HD costs approximately $200, so 8 channel costs $400 whereas the 4x10HD costs $500.

In the end you do the math and decide based on your needs what is the right solution. Define a specification and meet it.

Hey zbass,
I appreciate the response. I think you articulated a bunch of research that I did in a single post.

I have looked up the datasheets on the chips before - and compared the dynamic range -- and I probably spent more time than was worth it - comparing them and trying to decide what I really cared about. 103dB dynamic range vs 114 . The difference seems quite significant -- and I would have thought that was a big deal.... (I still wonder about the actual implementation dynamic range... since that's rarely ever as good as the actual DAC) until I stumbled upon this page, that was in the review that you sent:

www.audiocheck.net/blindtests_dynamic.php?dyna=72 (There are other ranges, including 78dB)

Quite remarkable to see what level of dynamic range you can and cannot hear. I was really amazed to hear the differences and see if I could pass a blind test. What I really would love is an analog 3x9 setup (so I could use it with three 3-way speakers)... but that's not easily achievable. I don't really care about wattage or about USB audio streaming... and since I need a bunch of channels, it's really a wash between multiple 2x4HDs and multiple 8x8 (4x10HD, etc) DSPs.

I don't really have the need for FIR filtering, but the flexibility sounds really appealing (in case I want to use it later).

So, like you said, I really just need to decide....
FIR (and more parametrics)+ lower dynamic range and (meaningless) worse THD....

or No FIR and higher dynamic range... and fewer parametric filters.

Anyway, thanks for helping to talk through this, it's been very helpful.

Thank you for clarifying the difference between 2x4hd and 4x10hd!

Is it possible to determine if 10x10hd has Sigma or Sharc chip? Or some other perhaps?

I purchased a 10x10hd without realizing the 4x10 was inferior to the 2x4... Hoping I did not make mistake!

Hi,
I've in use the 2x4HD and the 4x10HD. I cannot say that i can hear a difference due to the chips used, both sound great.
The reason for 4x10 HD would be (in my case) a three way system that i used to do with a Left 2x4HD and a Right 2x4HD but that is sometimes confusing if you change something and have to go back forward between the units.
Also the balanced outputs on the 4x10 HD make a difference as my amp can do single ended RCA or balanced on XLR. I believe i gained much more out of the system because of that. The gain setup of the 4x10 HD makes it more flexible as the 2x4HD is unity gain without a knob to turn another advantage the 4x10 HD has.
my next step would be to upgrade one of the 2x4HD to DDRC with Dirac to see if it will improve my setup even more.