Originally Posted by coctostan
Max, did u get hiss with the iNuke plugged into the speaker and nothing on the input? I believe that even if your aren't using any of the DSP settings it is still running through the DSP chip and circuitry which I'm guessing might be the issue. These Behringer and Peavey DSP amps likely have the absolute cheapest DSP chip and circuit known to man. If it saves them $5 per amp and they lose 10db of actual S/N it is likely worth it for them. If their DSP amps are spec'd at 10db worse than their non-DSP mates it is possibly even worse given how generous some of these companies sometimes are with specs.
I think I did some testing with different combinations of things plugged in or not. I was using a switch-mode USB charger to power the miniDSP, but I think I found that this was not the cause of the noise. I don't remember exactly what else I tested or how it turned out. I was just running active to get some experience with it, but planned to build passive crossovers anyway (in pursuit of simplicity).
I mentioned that I wasn't using the iNuke's DSP mainly to indicate that I was aware that it had the capability, even though I was using the miniDSP with it. I was using the miniDSP because that's what I had settings for, and programming the iNuke DSP is less convenient for me because it requires Windows (or hopefully, Wine).
That is a good point that the iNuke does another set of ADC/DAC conversions. I wonder if the non-DSP versions do that, too? I always considered the DSP versions "better" since I figured it just added DSP features, with no drawbacks -- but maybe that isn't the case.
Originally Posted by DS-21
Not surprising to me. The unbalanced miniDSP isn't the quietest piece, and the Inuke (even when not using the DSP) adds an extra DA conversion as well as an amp section with rather high gain and "extremely quiet" way down on the list of design goals. You'll get a lower noise floor results with a balanced miniDSP and/or (preferably "and") a quieter amp. You don't need much power for SEOS-based speakers at home. 30W/ch is likely sufficient. Save the Inuke for subs, and if you're running the SEOS's active consider something with less power and a lower noise floor. Then if noise is still an issue replace the miniDSP with a balanced (or "x8") one. (My 8x8 board in a 10x10HD case is MUCH quieter than my 2x4 unbalanced. I've never compared it directly to my 2x4 balanced miniDSPs, though.)
I've got a balanced miniDSP that I could try, also, but I already built the passive crossover for my SEOS speaker. Maybe I'll try it with my next speaker project. I'm also working on a bike project that will eventually include speakers, and I plan to use the miniDSP to save weight over a passive crossover.
I have an Onkyo 805 receiver, which I am quite satisfied with to power my SEOS speaker(s) directly at home. Also, very little hiss -- you have to put your ear up to the driver to hear any. :-)