Originally Posted by Scott27
Other than cost what is the downside of the miniDSP? Can it handle Atmos etc??
Warning: Long post with an edit because of a ham fisted accidental mouse click.
Oh certainly, Atmos is no problem as the Minidsp 2x4,2x4 Balanced and 2x4HD are all used as a Sub eq only in most cases. There are larger Minidsp units up to 10x10 that can be used for full system eq as well or I guess if you used enough 2x4 units it could work too. The numbers represent the # of input and output channels so 2x4 is 2 in 4 out and the 10x10 is kinda self explanatory.
The way Brother Pio is referring to using the 2x4HD is as a sub only DSP where the unit gets placed between the system receiver/pre-amp and the subs in the system. This allows signal manipulation after your receiver/pre-amp has already done the Atmos/DTS:X decoding. Although most of the signals coming into your receiver/pre-amp are digital, once decoded/processed the only signals sent out are analog(through the pre-outs or speaker outputs/binding posts), which is what the Minidsp accepts on its inputs( though the 2x4HD can also accept digital signals but not for the purpose of sub DSP). The Minidsp then does an ADC (analog to digital conversion) conversion to convert the signal back to digital allowing for the signal to be manipulated then performs a DAC (digital to analog conversion) conversion then is output to your sub amp/amps.
So what are the downsides?
The 2x4 models all accept differing amounts of max RMS voltage on their inputs and depending on how you have the units internal jumpers positioned, can act as unity gain devices, meaning they output the same voltage that comes in on the input, or the jumpers can be set to allow a higher input voltages(depending on model up to 4 or 8 volts) but are always limited in how much max rms voltage they can output by the maximum the mini can supply which is about 4.6v RMS for the Balanced and HD models and 0.9 volts for the unbalanced model. This can get a little confusing and I myself ended up ordering the wrong model (an unbalanced which is limited to 0.9v output and my amps all need a 1.4v minimum for full power output) when I was first learning DSP and had to end up selling it for the 2x4 balanced model I use now.
The voltage limits can become a problem also when adding large boosts or cuts as well if either are taken too far because it can lead to clipping of the Minidsp itself, so careful attention must be paid when setting up the gain stages and also when doing sub eq and/or BEQ corrections at the same time. There is enough voltage to work with in most cases but a close eye must be kept on a content to content basis especially if used for sub eq and BEQ at the same time.
So for instance if you are running sealed subs that need a +10db Linkwitz Transform and a few filters for a flat response during sub eq, this would limit the amount of BEQ boost that could be applied without clipping the Mini's outputs and should be watched closely. Now lets say during sub eq you only need to add a few mild +/-4db filters for a flat response then you would have much more headroom to work with than in the sealed setup with the +10db LT.
Now please don't take this to mean the Mini is severely limited because it's not. It is a really great piece or gear for the money and I love mine. I recently switched back to using my Mini on my IB and realized what I had been missing. Ever since building my SBA IB I have only used the Mini to eq and delay my Buttkickers and MBM's to blend with the IB and relied upon the DSP built into the 2 bridged Inuke 3k's that power it. Adding the MIni to the IB chain was a big boon for sound quality and took care of some very tough boomy harmonics issues I have fought for months to no avail. The instant the Mini was added the boomy drone was completely removed. Not quite sure how (though I assume through the filtering caps built into the Mini) but you can't imagine what a relief this is as I was considering tearing out the 1yr old IB to build sealed DO boxes for the 8 SI's (and I still might one day but am so relieved to not HAVE
to to get the SQ I knew the SI are capable of).
Edit: Accidently hit post before finished. Lol
The Minidsp is really the only option in its price range though if you have more to spend there are much better options out there. I am moving toward a Motu setup myself though I may be saving a while longer before it happens. The abilities of the Motu gear is on another level but so is the price unless you dig deep into the used market which I'm just fine doing and is how I have scored lots of my gear through the years. If you are interested in sub DSP I recommend doing all the reading here at AVS and on all the forums you can stand and be sure you become familiar with whatever unit you intend to purchase, before purchasing to save you the possibility of accidental mistake. I got excited and ordered the wrong Mini myself because I didn't know about the voltage output differences of the units because I had yet to read the Minidsp thread here at AVS. In doing so I learned everything I should have known before purchase and could have saved me money and time. There are tons of options in between the Mini and the Motu stuff but there are lots of things to consider like what job/jobs are you to use said DSP for.
If you intend to sub eq only you may be fine with something that will eq/crossover to 20hz only like some pro eq (i.e. Berry DCX or the like) do but if you intend to BEQ you need something capable of eq into the 10hz range or lower if possible to get the most from your efforts. So do your homework and be sure you maximize your DSP dollars and get the best tool you can for the job. All DSP units, I have found, have their own list of quirks from differing input connections to limited filter/crossover range to price and like everything else comes down to finding a balance of features and price you can live with.
Good luck and please don't hesitate to reach out through PM if I can help you with finding the right Minidsp/DSP for your rig and intended use. The Mini's are great products and will serve you will enough if you know and plan for their limitations.