[pjchappy]

Sadly, I am nowhere near the point of pulling the trigger on new speakers.  I plan on actively bi or tri-amping them. 

My system is computer based (PC to USB DAC/preamp combo).  I know many use the Behringer or similar speaker processors that serve as a crossover and DSP (for EQing out room nodes, etc.).  However, if one was to use PC based DSPs, wouldn't all they need is a crossover unit instead of a speaker processor device?  This would also have the benefit of avoiding the extra step in conversion that happens with the Behringer type units.

So, would a system that goes PC (using PC-based DSPs)-->DAC-->preamp-->active crossover-->amp be a good solution, or am I missing something here?


Paul

[Vincent Kars]

An alternative is a PC running DSP software doing the crossover and feed this into a multi channel soundcard
See the bottom of this page: http://thewelltemperedcomputer.com/HW/ActiveCrossover.htm

Or PC with/without roomcorrection software > DAC + volume control > Active speakers

[pjchappy]

Thanks.  However, to clarify, I would probably keep the set-up I have (PC-->USB DAC).


Paul

[Vincent Kars]

If PC > USB DAC is the case then an active crossover + amps + passives or active speakers.

[pjchappy]

OK, I may just go that route, then.

Why do so many others go the Behringer-type route then, with so many free DSP effects (parametric EQs, etc.) available?


Paul

[JDUBS]

Paul

I had a DEQX 2.6P and was investigating "upgrading" to a computer based solution.  Check out diyaudio.com...there are several threads on the topic. 

Anyway, long story, short, I bought a DEQX 3.0 and haven't looked back.  IME, there is nothing out there (computer solutions or other) that compares to it.

-Jim

[gunn234]

another interesting approach of late is the offering from www.minidsp.com

They sell a balanced kit as well and unbalanced that will allow you all kinds of crossover slopes, parametric and graphic eqs along with time delay. Hope to see more of these configs out there as it is a gaining more options through community feedback.

[JohnR]

Why do so many others go the Behringer-type route then, with so many free DSP effects (parametric EQs, etc.) available?

Maybe partly because of the need to get a multi-channel sound card, dedicating/optimizing a PC for the task etc. I'm not familiar at all with what's available in terms of hardware or software for the PC-as-source-and-eq/crossover approach, but in theory it could be a really good approach as the horsepower available in a PC may enable processing (depending on the software) that isn't possible on smaller embedded processors such as in the DCX and miniDSP. OTOH dedicated units like the DEQX mentioned are optimized already for the job... But still, to get started I'd second the vote to just get a miniDSP (2x4) and try it out - low cost, you'll learn something, and you can always get something more expensive or elaborate later if you wish.

Regarding the "extra conversion step" issue - to be honest I think this is a sky-is-falling type of thing. Just try it and decide for yourself if you can attribute anything negative to the "extra conversion step" - and, if you can, whether it outweighs the advantages you get from the processing that you're getting in exchange. Plus, there are a good number of ways now of getting digital into the processors... although sometimes you have to have a sample rate conversion in there... argh the sky is falling...

[pjchappy]

What about a non-multichannel PC-side set-up (which is what I am thinking of).  PC (with 2-channel PC-side DSPs) --> USB DAC --> preamp (2-channel) --> active crossover --> to multiple amps.  Am I making sense?  Is this alright?  Would love to hear from anyone who has tried this type of set-up.

I need to take measurements and experiment doing this with my current set-up -- just a passive 2-channel set-up.


Paul

[audioengr]

I used the DEQX at RMAF in 2009 for this purpose:

USB -> Off-Ramp ->S/PDIF -> DEQX -> S/PDIF -> Pace-Car reclocker 1 -> Overdrive DAC 1
-> Pace-Car reclocker 2 - Overdrive DAC 2

It was for a two-way system:

http://www.audiogon.com/cgi-bin/events.pl?empiricalaudio&99&ManuView&&&&&&&RMF09&#OPH

The problem with what you are trying to do is:

The crossover will need to be analog in and out.   In ALL cases, I have found this to be a non-starter.  Even the DEQX analog inputs are not as good as the internal DACs or digital feed-through.  The A/D section seems to be the weakpoint in these systems.  If you do it entirely with an analog crossover, you will be adding significant noise and distortion to the system.

It's also a really hard road to making this sound good.  Even with DEQX and automatic room correction and speaker correction with calibrated microphone etc.., it requires a LOT of hand-tweaking IME.  We spent days doing this at RMAF 2009, and ultimately were not fully satisfied.  We had identical amps for all channels, all battery powered.

If you go with an entirely S/W solution (there are not many), the problem will be what preamp to use with the microphone and how to calibrate it.

You are looking for trouble IMO.  Very few of these systems actually work-out and that is after spending at least $10K on everything.  Just stay with the 2-channel, 2 amp system and improve the crossovers in your speakers.  You can put $1200 into this and get spectacular results.  Use V-Cap.com copper teflons and jensencapacitors.com ribbon air-core inductors.

Steve N.
Empirical Audio

[pjchappy]

Thanks.  The potential problems of analog only make sense.

Regarding the DEQX, I saw they have a new HDP-Express.  I can't really tell what the difference is between that and the HDP-3?


Paul

[audioengr]

I didnt know about this until you brought to my attention.  I cannot tell the difference either....

I modded quite a few of the DEQX in the last 5 years and even put I2S interfaces on them.  They are quite excellent modded.  They even incorporated a few of my mods in the new version.  With a modded one, you have the best chance of pulling-off a bi or tri-amped system.  They may come up on Audiogon occasionally.  I dont mod them anymore.

I found it more troublesome to use the DEQX digital in to digital out with multiple DAC's.  It's like they didnt test this as well because hardly anyone uses it this way.  Multiple DAC's is expensive.

Steve N.
Empirical Audio

[JohnR]

What about a non-multichannel PC-side set-up (which is what I am thinking of).  PC (with 2-channel PC-side DSPs) --> USB DAC --> preamp (2-channel) --> active crossover --> to multiple amps.  Am I making sense?  Is this alright?  Would love to hear from anyone who has tried this type of set-up.

Sorry, I thought you wanted to do the crossover in the PC. Your description above is straightforward - I guess you mean an analog crossover but these days why, a miniDSP 2x4 will do it and set you back less than $200 by the time it's all said and done. (Plus the amps of course, which I assume you already have.) If you want to tackle a more modular DIY approach you can get the card version and a USB input card or SPDIF I/O cards; IIS output can be done too. But already we're going down the road of making it complicated instead of keeping it simple and learning.

I need to take measurements and experiment doing this with my current set-up -- just a passive 2-channel set-up.

That's pretty much a given whatever you do I reckon. You can get a calibrated ECM-8000 from cross spectrum labs I believe.

I'm not saying I disagree with Steve but let's take an analogy, just because you *could* spend a million dollars on a car and still drive it into a tree, doesn't mean you shouldn't learn how to drive. I don't actually think that just replacing an existing crossover is the best reason to do this (unless there's something wrong with it) but it would still be a useful way to learn - once you've had a go at it you'll see a lot better where to go next.

Just my 2c

[audioengr]

Sorry, I thought you wanted to do the crossover in the PC. Your description above is straightforward - I guess you mean an analog crossover but these days why, a miniDSP 2x4 will do it and set you back less than $200 by the time it's all said and done. (Plus the amps of course, which I assume you already have.) If you want to tackle a more modular DIY approach you can get the card version and a USB input card or SPDIF I/O cards; IIS output can be done too. But already we're going down the road of making it complicated instead of keeping it simple and learning.

That's pretty much a given whatever you do I reckon. You can get a calibrated ECM-8000 from cross spectrum labs I believe.

I'm not saying I disagree with Steve but let's take an analogy, just because you *could* spend a million dollars on a car and still drive it into a tree, doesn't mean you shouldn't learn how to drive. I don't actually think that just replacing an existing crossover is the best reason to do this (unless there's something wrong with it) but it would still be a useful way to learn - once you've had a go at it you'll see a lot better where to go next.

Just my 2c

All stock crossovers are junk IME, even in $30K speakers.  I've been trying to get some of the big manufacturers to change for years, but no luck.  They know better of course and are not even willing to give it a try.

Just replacing the bass inductor with a Jensen makes a significant improvement.  The reason why most believe that active crossover is the way to go is because most crossovers are so poor.  They dont have to be this way.

Steve N.
Empirical Audio

[TomS]

All stock crossovers are junk IME, even in $30K speakers.  I've been trying to get some of the big manufacturers to change for years, but no luck.  They know better of course and are not even willing to give it a try.

Just replacing the bass inductor with a Jensen makes a significant improvement.  The reason why most believe that active crossover is the way to go is because most crossovers are so poor.  They dont have to be this way.

Steve N.
Empirical Audio

Any US sources for those Jensen foil inductors?

[audioengr]

Any US sources for those Jensen foil inductors?

Not that I know of.  You might google jensen capacitors. 

email Jensen from his website.  I believe he sells direct.

all of my speakers have his inductors.

Steve N.

[TomS]

Not that I know of.  You might google jensen capacitors. 

email Jensen from his website.  I believe he sells direct.

all of my speakers have his inductors.

Steve N.

Yes, I found their site earlier.  No prices or US distribution though.  I assume the V-cap copper are bypasses only, since large values are rather cost prohibitive?

[JohnR]

All stock crossovers are junk IME, even in $30K speakers.

If the stock crossover is junk, then how would one know that it's designed well in the first place? Because if it's not, then just replacing parts is not likely to be a very cost-effective exercise... I say this having been down exactly that road.

[Hebrew Hammer]

So far I am loving my mini dsp 2x4 and can say that without hesitation that it's worth it's weight in gold..

the ability to tune your loudspeaker to your room will trump any passive solution minus the fact that extra cabling and channels of amplification is needed..

The wise tale of the detrimental effects of DSP needs to go away.. it's not the DSP that degrades the sound as it's the person not knowing how to use it and blames it on the dsp that does..

[cloudbaseracer]

I am not sure if it will do what you want but the Spatial Audio system from Clayton Shaw.  Tried to find a link for you but could not.  Hope this helps though.

heers,

James