Minidsp C-DSP 8x12 V2.0 Review

[rsqt]

You can get up to 12 outputs. You can route them as you want.

 

[sapphari]

Just a note to say that I have owned this unit for a couple years and love it. I hadn't seen this review till today and am happy to see the results. This unit replaced an AudioControl DSP/Amp that only had graphic EQ and the difference between that and this with Dirac is night and day. Those who say DSP doesn't matter in a car clearly have no experience. It's everything, and everyone who is serious about car audio is completely bought in. This unit with Dirac really is the best solution available today.

I agree the rating for this should be 'Fine' due to the analog input performance. Luckily I use digital input, so for me it is 'Great'.

There is an excellent, detailed guide for how to implement Dirac with this unit on the DIYMA forum, which was developed by some dedicated contributors to that forum.

 

[Newman]

I really wish Amir had taken measurements on the differential balanced inputs....

 

[Dumdum]

I really wish Amir had taken measurements on the differential balanced inputs....

It has single ended rca in, no true balanced inputs… the rca input may be some kind of floating ground or similar, but definitely not differential balanced like XLR input

 

[Newman]

It has single ended rca in, no true balanced inputs… the rca input may be some kind of floating ground or similar, but definitely not differential balanced like XLR input

As far as I can tell, it has fully differential balanced inputs (6) as well as the unbalanced RCA inputs (6).

 

[rvsixer]

So I am contemplating getting one of these boxes, and started digging into its use in a home environment.

And the three seemingly conflicting posts above regarding supported low-level input got me wondering even more. First step is of course actual manufacturer spec. This direct from miniDSP (from miniDSP website, as well as directly confirmed by miniDSP developer posts in their own forum):

C-DSP 8x12 has (6) fully differential balanced low level inputs (RCA connector)

And backing up the miniDSP spec, and helpful in clearing up the argument I see often here that balanced and or differential connection MUST have three wires to work:
www.youtube.com/watch?v=rgfZb1pEIrU

I'm left wondering if Amir's testing was with standard RCA coax having a common signal/shield tied to both devices (no true common modes between signal wires), or equal twisted pair signal wires without a common shield conductor between devices (CMR enabled). If done with standard RCA coax configuration, we may (likely imo) have seen some better SINAD numbers from the analog input tests done with CMR?

I am using the two signal wire, no common shield conductor configuration currently from AVR SE output to AMP XLR input with great success (and as recommended by both Hypex and Benchmark, per their tech notes to avoid ground loops and enable CMR).

 

[K man]

I'm left wondering if Amir's testing was with standard RCA coax having a common signal/shield tied to both devices (no true common modes between signal wires), or equal twisted pair signal wires without a common shield conductor between devices (CMR enabled). If done with standard RCA coax configuration, we may (likely imo) have seen some better SINAD numbers from the analog input tests done with CMR?

I’ve been wondering the same thing, but if Amir was using coax RCA it should mainly manifest itself as noise (not distortion) in the in/out measurements. While those measurements show quite limited noise and the SINAD is clearly distortion bound.

So either he used twisted pair RCA or he had very little interference.

The issue is very real though and anyone planning to implement this device is a home system should be aware of it.

I’ve used such a setup for several years, connecting six (unbalanced) channels out from my AVR to this device. I ran into massive noise problems in the beginning and it took me quite a while to figure out how to solve it. Which also included properly grounding the device - without causing any ground loops (which was tricky since I do use the trigger output to control the power amplifier).

Eventually I was able to get the noise level down to an almost inaudible level (where you have to put your ear 5cm from the tweeter to be able to pick it up at all), but it took some effort.

 

[rvsixer]

@K man yes and many thanks for your work, I have read of your efforts and outcomes notably the trigger induced issues (one of the reasons I use smart strips instead).

If it was normal days I would simply get the miniDSP Flex HTx; but nowadays with our new "tariffs", I simply can't bring myself to unnecessarily pay an extra 30% for it.

 

[rsqt]

I have no probs with noise. You need only one ground to each amp even if it is a 6/8/12 ch amp. A tweeter Horn with 109dB/1W is quiet in a distance of 1.5m.