[drphoto]

I know basically how active biamping works. My question is this...is there more to it than choosing the correct crossover point and slope appropiate for the drivers? (assume 2-way) I mean, don't passive crossovers often implement 'trap' circuits and the like to tame anomolies inherent in the drivers themselves? It sounds simple, but fear it could be opening Pandora's box.

The only active crossovers I'm aware of are Marchand and Bryston. Are there others? Which is best? (yeah...loaded question)

Maybe the simplest solution w/ a two way keep the passive network in the mains and use the active as a high pass and run a sub.

thanks,

joe

[Marbles]

There is the NHT X2 active crossover that makes it very easy to use the same subwoofers in combined 2 channel and HT systems.  It is realitively inexpensive at a full retail of $350.

With a 2 way monitor, it is realively easy to add a subwoofer and releave the 2-ways woofer from having to play the lowest notes.  This often cleans up the mids.

When I have monitors, this is my preferred method.

[woodsyi]

I know basically how active biamping works. My question is this...is there more to it than choosing the correct crossover point and slope appropiate for the drivers? (assume 2-way) I mean, don't passive crossovers often implement 'trap' circuits and the like to tame anomolies inherent in the drivers themselves? It sounds simple, but fear it could be opening Pandora's box.

The only active crossovers I'm aware of are Marchand and Bryston. Are there others? Which is best? (yeah...loaded question)

Maybe t ...

If you are only trying to add sub(s) to an existing 2 channel set up, the NHT will work fine.  But if you are thinking of bypassing a passive network with an external active set up, then you need to know exactly what your passive network is doing in order to get the right type of x-over.  It is more PITA but you get much cleaner sound out of each driver.  You can also match amp of your choice to each driver.  If you are only using digital source you can also get digital x-over which have more flexibility.   I use a Marchand XM-44 3 way.

[R_burke]

There are several "Professional" brand active crossover units available.  Behringer and Rane are just two.  They are considerably less expensive than "Audio" crossovers.  Roger Sanders who designed the Innersound ESL Hybrid speakers recommended that I try Behringer for my ISIS speakers.  You can usually find both Behringer and Rane on EBAY in the Musical Instruments/Pro Audio section either under Rack Mount or Other.

[oris98]

Has any one tried the Behringer, Art or Rane these types of elec. XO with audiophile graded equipement ?  Does it degrade the sound out of your system due to the relatively cheaper components (May be) ?  How does it compared with Bryston, Marchand, etc ??

Many thanks..

[Scott F.]

I'll second the NHT active XO if you are doing a two way.

There are quite a few other active XO's to choose from other than the inexpensive Pro-Sound XO's. The vast majority of them are vintage (but don't let that scare you off).

Pioneer makes several models. All of them are from the 70's. Most of them were 3 way XO's that could be run in full range, 2 way or three way moses (they even made a 4 way XO). Their model numbers were (basically) the SF700, SF750, SF850 and the D23 and D24 (I might have missed one in there). These can be found every couple of months on eBay or Agon and the price varies by model but runs $250 (for the first SF700) up to as much as $800 for the D24.

Sony also made a 3 way XO back in the 70's. It was the TA 4300. In the past ten or so years, I've personally seen two of these, one of which I owned (and just recently sold). The ones I've seen sell for about $300 (good luck finding one though).

Audio Research made several different models. They were all tubed. They made 2 ways (EC2) and 3 ways (EC3). They varied between the years. Some of them had variable XO points, some didn't. The ones that didn't you had to swap resistors and caps to change the XO points. These sell for between $500 (EC2 fixed XO points) to $1200 (EC3).

Ron Wellborne just introduced an active 2 way XO kit. It's about $150 and uses an opamp. You need to add a power supply (a wall wart will work but something better is strongly seuggested). It looks to be a pretty nice unit. If I remember right, it has fixed XO points.

Several of the true high end mfgrs made XO's also. Naim, Levinson and others also either made or still make them but they are pretty pricey.

Now for the ProSound XO's. I'm not trying to start a flame war here, I'm only relaying my personal experiences in my systems (I've been either bi or tri amping for 6 years this last go around) (Oh, I used to do it back in the 70's too but that doesn't count in my books).

Now this is just my opinion, but I would stay away from these things in an 'audiophile' system. The reason I say this is first, I've tried several of these and they all sound dodgey at best. Pro Sound XO's (Behringer, DOD, Peavey, DBX, Ashley and others) typically perform WAY more functions other than being a basic XO. They do time delays for time alignment, low pass cut offs (subsonic), phase switches plus a host of other goodies (all of which vary by mfgr obviously).

All of these nifty gizmo's in the prosound XO's come with a sonic price. Each feature has it's associated electronics to make it work. More electronics usually means less sound. These prosound XO's typically use cheap opamps for gain stages. That is the last thing you want in a high resolution system. And finally, the XO points rather than being a decent multi-step switch with fixed resistors or caps, typically is a cheap pot.

As you can tell, I'm not a fan of the prosound XO's but thats just me. Lots of guys out there seem to like them. In my systems, I can hear them and I don't like the way they sound.

What I'm using now is the Pioneer SF750 in my high powered tube system and an AR EC-3 in my SET system. The Sony XO is more transparent than the Pioneers. Of the Pioneers, the SF 700 is the least transparent. I personally like the AR XO's but they are tubed (and I'm heavily tubed biased).

Knowing Ron Wellbornes ear, his little kit probably sounds way better than it should. The NHT is a similar design to Ron's and I'd bet (without actually hearing one) it sounds decent too.

Hope that helps.

[nathanm]

If you pysch yourself out about the scary "cheap" components in the pro sound equipment you might be missing the actual results of active biamping itself.  The nice thing about the pro sound stuff is that it does have extra functions that the audiophilish stuff doesn't have, and since it is a very tweaky thing to try it can be beneficial to have those gain trims, phase reversal switches, mutes and whatnot.  You're going to hear the results of your adjustments before you hear the results of the cheap components.

Since it is a 'risky' experiment to try I'd say you're better off going for an inexpensive Behringer or Rane unit which has more tweakability than to drop hundreds and hundreds on the fancy stuff.  (don't forget the crummy resale value)  Just having a variable pot which controls the XO point as opposed to a fixed, snap-in module will tell you much more about where that point should be.  Perhaps if you can arrive at a setting which sounds good you can then consider more audiophilia nervosa parameters.

Maybe the simplest solution w/ a two way keep the passive network in the mains and use the active as a high pass and run a sub.

That is what I ended up doing myself with my system, but still the bi-amping journey was an interesting one.  I guess another seemingly no-brainer point to mention is to know for sure  if the internal passive circuit in your speakers can be bypassed.  Obviously if you're putting TWO crossovers on top of each other that's no good. heh!

[drphoto]

Excellent info and discussion. Thanks.

So if you go active on your two way....it's pretty much trial and error?

[Kevin P]

To get a proper active crossover design for a system you need to have a way to take measurements.   We don't use simple text book crossovers because they don't work.   A speaker is both an electrical AND acoustical system and the active crossovers only acount for the electrical response of the system.  

Your going to get much better results with the standard passive crossover unless you have the ability and equipment to measure the system and then properly design the active crossover.   The pro-sound units offer very little flexibility.   You need to find a bare PCB that allows you to stuff op-amps for various networks.   Linkwitz has a couple boards that have a lot of functionality.   There is a lot of engineering though that goes into crossover design, active or passive, so unless you plan to spend a few years learning I'd suggest buying an off the shelf system already designed by a competent engineer.

You could try passive bi-amping if your speakers allow.   They give you much of the benefit in terms of removing the back EMF of the woofers from the midrange/tweeter networks.   The tweeter/midrange networks are typically easy loads with very little power demands in comparison to the bass.   The large flux modulation of the woofer under high power conditions would be isolated from the midrange providing you with a large part of the advantage of using a multi-amped system.