DSP Active Crossover

@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. 

@jaytor wrote:

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. 

Kind of the same thing I’m doing now; previously I used my Xilica digital DSP for both the main speakers and subs as an active digital crossover, but my new (used) main speakers have built-in amps and active analogue crossover, so the Xilica unit is now only used over the subs and high-passing the main speakers. I may use the Xilica for slight PEQ corrections over the mains eventually, but it’s still early days. 

My incentive to replace my previous main speaker system with this one wasn’t to pursue analogue active per se, I might add, but rather design elements of the speakers themselves. A great result can be had with either active option, be it a quality DSP-based (with or without an additional A/D to D/A conversion step) or analogue variety. However discerning whether there might an inherent advantage with an analogue active approach in itself like the Stage Accompany design I’m using now vs. the Xilica is difficult to assess due to many variables. 

@phusis I have been playing with the cheap Behringers units, both digital and analog versions for a lil bit.

PEQ (which can be a matter of taste), crossover and levels aside,....the critical parameter is individual driver delays, optimal phase characteristics for a 3 way horn at least...which decides whether that magic happened or not. It seems a bit of a science in itself how/why a manufacturer arrived at their optimal values (looking at how different pro speaker manufacturers have done it).

It would be silly, for example, to do a lascala without it.

Even the cheap analog behringer unit has one LF delay knob. It is missing one for the MF, HF.  If a analog crossover didn’t come with individual delay knobs period ( sublime, marchand, whatever), might as well throw it in the discard pile.

I suppose one might as well imagine the digital units to be the DAC itself (pay up a bit for that reason) and come into it with a high quality AES digital input.

but rather design elements of the speakers themselves. A great result can be had with either active option, be it a quality DSP-based (with or without an additional A/D to D/A conversion step) or analogue variety. However discerning whether there might an inherent advantage with an analogue active approach in itself like the Stage Accompany design I’m using now vs. the Xilica is difficult to assess due to many variables. 

@deep_333 wrote:

@phusis I have been playing with the cheap Behringers units, both digital and analog versions for a lil bit.

PEQ (which can be a matter of taste), crossover and levels aside,....the critical parameter is individual driver delays, optimal phase characteristics for a 3 way horn at least...which decides whether that magic happened or not. It seems a bit of a science in itself how/why a manufacturer arrived at their optimal values (looking at how different pro speaker manufacturers have done it).

It would be silly, for example, to do a lascala without it.

Even the cheap analog behringer unit has one LF delay knob. It is missing one for the MF, HF.  If a analog crossover didn’t come with individual delay knobs period ( sublime, marchand, whatever), might as well throw it in the discard pile.

I suppose one might as well imagine the digital units to be the DAC itself (pay up a bit for that reason) and come into it with a high quality AES digital input.

Yes; there’s the specific filter use, i.e.: either active analogue or active digital/DSP, and its features at play (a DSP-based solution will have an advantage in its sheer breadth and also(?) precision of features), and then there’s the actual sonic imprinting of each of these filters - not least compared to a passively configured scenario. Obviously quality varieties abound in each group of filter type, and a particular speaker design may be more or less in the need of the many features provided by a DSP. As you imply, the Klipsch La Scala’s or other horn speaker varieties call for DSP filtering, but mostly nowadays - whether the specific design really calls for it or not - actively configured speakers are usually DSP-based. A quality outboard DSP unit will give you a multitude of features and options for settings, and as a DIY’er it’s a boon to configure and experiement with these on the fly from the listening position via a laptop/tablet.

As you suggest, DSP’s can also be an integral part as a high quality main D/A-converter (DEQX comes to mind). With that in in mind, some may question the complexity of a DSP in an actively configured chain after what’s used as the main D/A-converter with added conversion steps (maybe even A/D to D/A with an analogue input) in a high quality stereo setup before sending the filtered analogue outputs to the respective amps, but from my chair and in the greater scheme of things it’s the preferred scenario in light of the better amp-to-driver interface it provides with the absence of the passive crossover in between. With a high quality unit from the likes of Xilica (now ACX), XTA or Lake, the DSP being an actual impediment in the signal chain sonically is debatable, if not isn’t - for all intents and purposes - transparent. Audiophiles are quick to sneer at added conversion steps, in some cases not without merit, but it takes actual experience with high quality outboard DSP’s to make an informed call on this.   

With a fixed filter setting analogue active crossover like the one sitting in my Stage Accompany speakers (that is: there is individual driver level adjustment, polarity switch and other) it’s a simpler user-approach, for sure, and you would assume the filter values to have been done very capably by the people behind it to accommodate the specific drivers + horn (it certainly sounds that way). It’s worth noticing btw. that the amp channel feeding the planar magnetic driver from 1kHz on up is the more powerful one vs. the amp channel to the woofer (350 vs. 250W, even though the planar magnetic driver w. horn is the most efficient one), and this goes contrary to the typical (blind?) approach with less wattages to the tweeter/mids section.