DSP Active Crossover

I'm considering trying a DSP-based active crossover in my system. I did a search to see how much this has been discussed, and most of the posts are pretty old or about active speakers. DSP technology has changed a fair amount in the last 15-20 years.

My system is digital only, and my speakers are 3-way, so it's not particularly complicated. I've been looking at the Danville Signal dspNexux 2/8 which has two channel in (with digital inputs) and eight balanced analog outputs. This appears to be available with AKM AK4499 DACs which are fairly well regarded sigma-delta DACs (although I don't know how good their implementation is).

This product has a fairly rich DSP software environment for programming filters, time delays, etc., so it should be fairly straightforward to set it up to replace my passive crossovers. 

My biggest reservations are 1) giving up my Denafrips Terminator+ DAC and nice-quality DIY preamp, and 2) using the DAC's digital volume adjustments. 

This unit is about $3K (maybe a bit more with the AK4499 DACs), so isn't terribly expensive. From the limited research I've done, this unit appears to be higher sound quality than the miniDSP or DEQX boxes, but I could be wrong. All my amps have balanced inputs, so I'd prefer to use a unit with balanced outputs. 

So, what I'm wondering is if the benefits of active crossovers and dsp equalization will outweigh the lesser DAC quality (assuming this is the case) and lack of analog volume control (currently using a relay switched attenuator). I'm also wondering if there are other dsp audio processors that I should consider (digital inputs, at least six channels out, ideally with balanced outputs).



I am hal2010, AKA Richard Hollis.

If you have any questions about DSP crossovers for the dspNexus 2x8 system, will be happy to answer them.

Best regards,


I've heard several systems with the mini DSP, and have been unimpressed. 

I've also heard several very high end DSP systems, including the Kyron. And that system kills! Even Mr. analog, Michael Fremer loves it.

But my overall evaluation is, that it takes a very special DSP speaker system to best the best passive system. 

Most systems that use the Minidsp stuff are low end systems. I don’t know any high end speaker company that uses them (anyone?)......however, the latest Minidsps are very good. If you are just making a 2 way speaker like I have described then the ultimate version (using regular analog amps and not digital amps) would be using the digital only minidsp that costs $500 and add a better power supply and run out of it digital into the DACs of your choice. Use a serious DAC on the mid-tweets and a less expensive one on the woofs. This would compete against lots of super high end speakers. The DACs in the latest Minidsp are good but not great. Same with the dspNexus......just AKM DAC chips and op amps.....the same as $500 separate DACs. The dspNexus has the advantage of having more channels if you want to tri-amp or bi-amp plus subs. It would be great if there were a version of the dspNexus that had digital outs....so any system using it could be improved with better sounding external DACs. The Minidsp SHD has both analog outs and digital outs...but, it is a two way only.

See my post on 9-22 above for the link to my webpage that describes all this (recently updated).

@simonmoon wrote:

I’ve heard several systems with the mini DSP, and have been unimpressed.

I’ve also heard several very high end DSP systems, including the Kyron. And that system kills! Even Mr. analog, Michael Fremer loves it.

But my overall evaluation is, that it takes a very special DSP speaker system to best the best passive system.

It’s not as much the DSP unit as it is the implementation. My IIR-based DSP unit cost me just over just $1,000, and it’s an excellent piece of equipment for what it’s supposed to (make me) do, and one that also holds up perfectly well to Lake units (costing much more). That’s for nothing however if you don’t know how to turn those settings into proper, audible effect, of which there are different routes for that to be accomplished. I still prefer setting DSP-values manually by ear with the aid of measurements (and input from friends), and while a painstaking and lengthy process the results can be, and actually are extremely good.

Of a range of passively configured speaker setups I’ve heard that were converted to outboard active configuration - that is, bypassing their build-in passive crossover completely and replacing them with line-level DSP’s/electronic XO’s and more amps - each and every one of them eventually saw a substantial upgrade in sound quality over their passive iteration (and that was obvious fairly early on), to everyone listener involved. That’s all I need to know and a testament to the potential of active configuration, not least from the important basis of comparing the same speakers with different filter configurations.

Many are, on principle, against DSP due to speculated, negative effects of A/D-D/A conversion steps with analogue inputs only, but with no experience to really speak of that would actually single out this particular aspect as the detrimental factor. Why even make any assumptions as to what may or may not, technically, be the reasons for a speculated deficit?

One of the best setups I’ve heard, an outboard active one at, comprises the exact same DSP unit I’m using. For anybody wanting to tell me it’s an IIR-based filter and not a FIR ditto, while implying perhaps it’s the lesser solution, I can only stress the importance of seeing the forest for the trees in actually listening to a properly implemented active setup and let your ears decide. Should the FIR-filter hold the upper hand sonically, which theoretically it does not least in being able to generate linear phase response, that’s only an added bonus that will potentially distance active from passive even further.

The minidsp SHD (2 way digital xover) uses an ESS 9028 DAC chip......pretty good. The Audiophile Junkie (see his Youtube channel) uses this Minidsp SHD in his super system. I posted this on a couple of other threads.....but I cannot stop talking about this....so here goes again.

I have been quietly following this thread. have a feeling that the OP will be thoroughly disappointed with the minidsp SHD since he appears to be used to a Denafrips dac and whatever preamp he’s got.

For my attempted application, i tried to replace the Denafrips Hermes+Venus and a Yamaha C5000 with the minidsp SHD in pursuit of an active crossover. The SHD is awful in comparison and i just got rid of it.

To each his own....(with the theory crafting n all).