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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).

jaytor
deep_333
2,436 posts
 

@jaytor  Your questions require a more philosophical examination of the ethos applied to some products.

For example, i have a Yamaha flagship c5000 preamp in a more purist room... you open it up and you can see that it is a work of art. The same guys/same brand also offered a very nice preamp processor that i keep in my next room (greatly subsidized by the hometheater dudes) .....where you can setup an atmos speaker array and manipulate a soundfield 500 different ways if you want into sonic nirvana (within the dsp domain). 

I could do dsp for days too, but, would i put that c5000’s analog output through a ADC. The answer for me is no....

You could get a cheap analog behringer cx3400 and try out different things just to examine the end execution. You could try modding it.

Or, these harrison labs guys offer some in line high pass/low pass filters, attenuators, etc pairs in both rca and xlr versions. They are quite decent actually. You could probably ask them to do something custom for you too, keep it simple.

https://www.hlabs.com/ 

You could implement PEQ upstream of your denafrips dac perhaps.

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. 

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).

jaytor's avatar
jaytor OP
778 posts
 

@deep_333 - Yeah, I have put this on the back burner for now. I'm having too much fun experimenting with different lDIY line stages and amps. My latest EML-20A DHT based line stage has made a significant improvement - I love the way this sounds. 

At some point when I finish some of my other projects, I'm going to try an analog active-crossover and use Roon's DSP functionality to make any corrections necessary. 

deep_333
2,436 posts
 

It would be cool if some guys building analog preamps  implemented some high quality analog active crossover features (defeatable, of course) in their analog boxes....maybe accuphase, schiit, yamaha, angela yeung, whomever...

I am sure a considerable number of guys would pick a preamp with such analog features over some competitor who doesn’t have anything. 

 

@deep_333 - Yeah, I have put this on the back burner for now. I’m having too much fun experimenting with different lDIY line stages and amps. My latest EML-20A DHT based line stage has made a significant improvement - I love the way this sounds. 

At some point when I finish some of my other projects, I’m going to try an analog active-crossover and use Roon’s DSP functionality to make any corrections necessary. 

erik_squires
17,544 posts
 

@deep_333  - Parasound had probably the most flexible and innovative preamps in regards to this.  The P7 for instance was stellar. 

deep_333
2,436 posts
 

@erik_squires I think that parasound came with analog bass management (i.e. had crossover limits to the subwoofer range) but, got confused along the way with the multichannel slant....i get the feeling it made some hometheater dude pick it up and say "where’s my hdmi??!!". The average hifi dude probably never even looked at it....grand opening, grand closing....

The hifi purist stereo analog preamp box guy who markets himself as the "heart of the hifi system" instead needed to say...."Oh, you have a pair of subwoofers...look, here is analog hifi bass management for you so you can correctly pull in your subwoofers and....you want to do some stereo 2 way or 3 way active all analog with 500hz and 1800hz too whilst you spun your turntable?? Here it is...you keep your creme de la creme terminator dac or turntable's output, as is, and send our outputs to your creme de la creme power amps all analog"

That would have been a homerun for the "heart of the hifi system", not just another rinse/repeat box with a different polish on the chassis.

Maybe, i’ll write a letter to the schiit guy.

@deep_333  - Parasound had probably the most flexible and innovative preamps in regards to this.  The P7 for instance was stellar. 

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