Digital vs Analogue active x-overs

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
P

phillil

Member
Joined 2018
I'm new into the world of DIY audio, other than making many subs over the years, but I'm in the process of replacing my system (speakers) with DIY.

I will be experimenting with x-over design using my high-end multi channel Classe pre-amp and JRiver, but once I've settled on the x-over fequencies I'll need to x-over the stereo anaolugue signal ouput by my Classe pre. (which I use for music and movies)

For everything below 500Hz, I'm happy to use my Behringer iNuke 3000DSP, (SQ not as important below this) but I'll need something for my proposed mid/treble cabinets.

I'm reluctant to go with something like miniDSP for digital DSP, / xover becuase the quality of DAC will be a major downgrade from my Classe, and I have read many people don't rate miniDSP.

I'm also reluctant to replace my Classe with something like a DEQX, becuase then I'll need a separate AV processor. (plus I'll lose 1,000s selling my Classe)

Therefore I am considering 3 way analogue op-amp based x-over (eg based on the OPA2136 op-amp)

Help, advice, thoughts etc appreciated...

"Digital vs Analogue active x-overs!!"
 
D

DualTriode

Member
Joined 2009
Hello,

A small confession. I cannot settle in on a set of drivers that I want to keep in the stack. Lately the midrange drivers have been JBL 2108’s or JBL 2123’s. The tweeters have been JBL 2425’s or JBL 2450’s with controlled directional horns. I like the Eighteensound XR1064 on the JBL 2425’s. http://www.eighteensound.com/Portals/0/PDFs/XR1064.PDF

I like the sound stage with the controlled directional horns; the high frequencies do not bounce all around the room so much. The sound stage is more focused. I use a Rane AC23s for the crossover. The crossover frequencies are adjustable. As DR. Sean Olive says you can hear a difference. I have a hard time with a preference.

Thanks DT
 
Brett

Brett

Member
Joined 2002
Depends what you want it to do. EQ? Much more circuitry and harder to do analogue. Delay? Not much available analogue. Phase correction? Not really in analogue. Steep slopes? Much harder and more cctry in analogue. All a piece of pie in DSP.

DAC concerns? You can get the miniDIGI board and add your own outboard. DACs are much overrated in terms of system sonic signature anyway.
 
P

phase_accurate

Member
Joined 2002
Simply because analog is still much more sexy to DIY and therefore the final target is an analog active crossover. I don't do any work twice BTW. I do one of two necessary steps in a much more convenient way. I would have to fiddle with parts and topology on a breadboard when going analog from the beginning. This is much faster and convenient in digital and cheaper as well.

Regards
Charles
 
KSTR

KSTR

Member
Joined 2007
Brett said:
Depends what you want it to do. EQ? Much more circuitry and harder to do analogue. Delay? Not much available analogue. Phase correction? Not really in analogue. Steep slopes? Much harder and more cctry in analogue. All a piece of pie in DSP.
Click to expand...
I for one always felt that the main work in x-over design is doing proper measurements and preprocessing first, then carefully selecting the wanted target responses for the acoustic output chararistics (x-over definition). From there you need to obtain the correction function to be applied to each driver (filter definition) which then can be used to synthesize either the analog circuits or to set up a DSP with IIR/FIR/DLY.

All this can be done with various hardware and software packages (including real-time emulation of analog filter circuits). In this way choosing analog over digital or vice versa is more a choice of final output format for the general process. The implementation part can range from old-school analog (use one of the better analog x-over hardware units, combine with EQ if required) to "point-and-click" X-Over/DRC software with a lot of built-in "intelligence".

Of course pure analog has its restrictions whereas pure digital needs good quality multichannel DACs. Both have their own merits and limits.
For DIY, if there is a chance that you want to continue to experiment with active XO speakers with other drivers and concepts I'd always opt for the pure digital mutichannel solution which is very flexible. You can still make it sound like a simple analog circuit.
 
P

phillil

Member
Joined 2018
All thank-you very much for all your comments - it is very much appreciated.

I think I'm leaning toward keeping JRiver for DSP duties for music....
It can split the Left channel into 4 separate DSP'd channels that can be mapped to any corresponding AV channel (eg Left >3200kHz = Surround Left, Left<3200Hz & >1200 = Rear Left.... and so on)
It can do the same for the right channel then send all 8 channels across HDMI LPCM to my Classe Pre-amp.

My Classe will then be set to "discreet" mode LPMC to output 8 channels to my active speaker power amps without the need for additional processing.


My issue is then
o because my active speaker power amps would be connected to the Classe AV pre-outs, I would need to unplug them and re-connect my current center and surround power amps for movies
o I would also need a different way to split/x-over the FL/FR from my Classe to my active speaker power amps (eg cheapo version of miniDSP)

So to eliminate the need to swap all the cables about each time I switched between music and movies I could purchase (or build) an auto switching line-level device. I guess this would be a box containing a bunch of relays to switch the inputs of my active speaker power amps (between Classe ouputs for music and miniDSP outputs for movies)

Does anyone know if such an auto line level switcher exists (or recommend a relay x8 to build one myself??)

I think I'd prefer to use my Classe for both music(+JRiverDSP) and movies(+"cheap version"miniDSP) in conjunction with a DIY line level switcher (8 channels) rather than buy a separate additional AV receiver, or sell my Classe.

I like the look of the Analogue Precision DSP processor mentioned earlier in the thread, but I'm not actually sure how to buy one!! Plus I'd need a new separate AV receiver :(
 
Juhazi

Juhazi

Member
Joined 2007
Gentlemen - excuse me but modern ad/da and dsp easily exceed the performance of analog sources and power amps. Thou shall not be alarmed!

Still one must know her/his tools and use them properly. It is too easy to set unsuitably low or high (analog) signal level to AD's input, which leads to low S/N or high THD or clipping. And often we have several AD/DA operations chained...

Perhaps one should sacrifice a few minutes to think about how many conversions the "recording" has gone through before hitting the first dsp at home of the consumer!

Free your mind and be happy with dsp!
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom