Advice on active crossover equipment.

I want to try this out with my DefTech towers as they absolutely LOVED passive bi amping and I have a feeling it can only get better if I go active. In addition I want to have the option of converting my many pairs of two ways to use this method as well... ok here's what I have...

A B&K Reference 50 preamp with both unbalanced and balanced output.

TWO Outlaw 750 amps (5 channels @165 per channel) with unbalanced inputs.

I have a potential 10 "monoblock" amps that I can use for all sorts of stuff, but all the cheap active crossovers are pro units with XLR connections... no problem for the B&K, but a no go for the Outlaw amps.

Is it possible to add balanced inputs to the Outlaws? Failing that, is it horrible to get XLR to RCA adapters? That would solve the problem in under a minute and for 20 bucks per amp.

Or is there a crossover that has both RCA and XLR outputs? If so, what's the difference between that and a cheap adapter?

Is there a kit? I will build a kit, but I don't want to go from scratch.
 
Hi,

For most high hifi speakers you can't simply go active
with standard active filter functions, you need bespoke
active filters that match or better the passive filters.

Best active setup with two equal power amplifiers is
IMO a 3 way with active bass to mid x/o's and passive
mid to treble x/o's.

For active 2 ways you can get away with a smaller
treble amplifier, especially as the tweeter will
have no attenuation. Still the x/o has to be right,
including correct phase, BSC and driver EQ.

Not a simple task unless you go to digital
programmable EQ and know what your doing.

e.g. : https://sites.google.com/site/cdenneler/home/lxc

rgds, sreten.
 
Possible to add balanced input to Outlaws? Technically yes, but it's impractical and unnecessary to achieve your goal. XLR>RCA adapters are fine for your application. Sometimes going RCA>XLR can have an issue, but not in this case.

Marchand and Bryston make analog crossovers with RCA outputs. Most other crossovers are digital filtering which allows more flexible tuning of the crossover, with more EQ filters available to duplicate the passive filter functions. Digital crossovers with RCA outputs include DEQX, Legacy Wavelet, maybe others? Most commercial crossovers are intended for professional use and have balanced outputs. But you can drive your Outlaw amps using XLR>RCA adapters.

Be careful because most pro equipment has higher voltage output levels (5V+) than consumer audio products (2V.) So always set the output level to zero on any crossover box first, before turning on the amps. You may want to measure the positive leg XO output with full scale test tone to set the XO output levels to match (or stay lower than) the amps' full power input voltage. Just be careful, especially with tweeters using a high power consumer amp with a pro level input.

I agree with Sreten's recommendation of using active for the bass>mid XO, and keeping the mid>tweet passive crossover, for several reasons. The M>T crossover has more EQ requirements to make it sound good. Deftech does a really good job with this, they spend a lot of time integrating the drivers and you will be hard pressed to make it sound as good without their level of knowledge and development time. The passive speaker level filters used for M>T crossover are appropriately sized and less distorting than those undersized parts used for W>M so the advantage of active XO for M>T is much less than W>M. There is a huge advantage to connecting the amplifier directly to the bass drivers and avoiding the passive XO on bass drivers - even bigger advantage than biamping. It is much easier to make that W>M XO sound good than the M>T XO when rolling your own XO filters with digital crossover box.

Be aware that the sound quality of electronic crossovers varies proportional to the price.
Have fun!
 
Thanks guys! I worked in television for a long time and I have a few engineer friends that I will be able to bribe with some grilled ribeyes and beer to help me set the speakers up with oscilloscopes and 30+ years of experience.

The speakers I want to experiment with are the DefTech Bp2002 towers. It's called a "speaker array" because it's really a two-way bipolar with a powered sub incorporated into the bottom. They have three-way binding posts and removing the jumpers allows the highs and mids to be powered independently. So though I'm not 100% sure, I think the bass-mid is not crossed over in the traditional sense... it has it's own amp already.

In fact, I've been running them with the jumpers to the bass module removed since the first day. I run a cable from the sub out of the preamp directly to it.

This may mean I am already doing something very similar to what sreten proposes (unless I'm not understanding..which is possible...nay, probable!) although a subwoofer is not really a woofer...

I have wanted to build a pair of proper three-way floor standers or failing that, buy a used pair that perhaps is known as a good candidate for this kind of thing? The DefTechs were going to be the Guinea Pigs becuase they were there, but the whole bi or tri amping thing is ultimately for the analog system which lives in a different room altogether.
 
Manny,

What kind of sources do you use? And do you listen to music only on these, or movies too?
I ask because I think software-based crossovers and digital signal processing with the right software and right equipment are a fantastic alternative. Plus it allows for proper room correction. I started 100% analog and "audiophile purist signal chain" and have converted to 100% computer front-end.

Here's a good article: Computer Audiophile - Acourate Digital Room and Loudspeaker Correction Software Walkthrough
And here's part II of the above, which will be more of your interest: Computer Audiophile - Advanced Acourate Digital XO Time Alignment Driver Linearization Walkthrough

The big limitation I think is doing video with it, because of time-lag introduced by DSP. I know some people use it, though.

Anyway, thought it might be of your interest.

Cheers!
 
Hi,

FWIW this design is a good candidate for active driving using three amplifiers :
Zaph|Audio - ZDT3.5 . One each for the bass units, another for the M/T.

Study carefully. The bass mid x/o's is essentially 1st order electrical and can
be implemented at passive line level, tweaked with quasi second order PLL.

Keep the M/T x/o. Most of the complications of the
x/o are removed by going active for the B/M x/o.

PLL filters are dirt cheap and all you need. lose :
R4, C7, R14, L13, C12 and all the bass components.
Use the free TinaTi to match the transfer functions.

Zaph gives you the electrical transfer functions,
for bass to mid just apply them and don't worry
about the mids impedance compensation, as
you have active low impedance drive to the mid.

rgds, sreten.

http://www.ti.com/tool/tina-ti
 
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Manny,

What kind of sources do you use? And do you listen to music only on these, or movies too?
I ask because I think software-based crossovers and digital signal processing with the right software and right equipment are a fantastic alternative. Plus it allows for proper room correction. I started 100% analog and "audiophile purist signal chain" and have converted to 100% computer front-end.

Here's a good article: Computer Audiophile - Acourate Digital Room and Loudspeaker Correction Software Walkthrough
And here's part II of the above, which will be more of your interest: Computer Audiophile - Advanced Acourate Digital XO Time Alignment Driver Linearization Walkthrough

The big limitation I think is doing video with it, because of time-lag introduced by DSP. I know some people use it, though.

Anyway, thought it might be of your interest.

Cheers!

I use a plethora of turntables, among them a Music Hall MMF-5 and a Sony PS-X5 as well as a few different phono stages (Hagerman Cornet, Bugle and Music Hall Phono Box. For CD I have a generic Samsung BluRay player.

I don't listen to files much yet, but I'm not a Luddite. I will most likely be incorporating hi-rez into the system via an Oppo with a hard drive full of FLAC files. Just not this year...

The preamp is likely to remain the B&K Reference 50 since it has the proper XLR outputs and great stereo sound. Since my first post, I have decided to start acquiring Crown amps when I can find decent used ones... The old DC-75 models are great mono amps with balanced inputs and don't run too hot. Getting four or six of those shouldn't be too expensive or difficult.

I have also come t the conclusion that none of the speakers I own are really good candidates for bi-amping... So I am going to look for a suitable pair or most likely DIY something. I have a feeling the extra effort will be worth the trouble.

And yes... 100% music. The home theater is in a separate room.
 
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