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Active crossovers, implementation


tromprof

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Which passive crossovers do you have BTW? And how do you make the cross to the F20s? Your system must sound awesome already :emotion-21::)

 

I am using the Crites a4500 crossovers, modded a little (squaker tap moved down to 3 to accommodate the EV drivers and bigger tractrix horns). The Pioneer receiver handles the crossover to the F20s. I am currently crossing at 50 HZ between the QP bins and subs. Once I get this up and running I might try it a bit higher (60 HZ?).

Yes, it does sound really good.  I am looking forward to hearing what having the bottom end time aligned sounds like.

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I am looking forward to hearing what having the bottom end time aligned sounds like.

 

I'd recommend playing one speaker (i.e., mono) using correct time alignment...then dialing the delay back to zero (or whatever the delay/phase was using passive crossovers).  You should hear a significant change in timbre at the crossover point (probably about 400 Hz).  When I did this trick with the center Belle, it wasn't very subtle - it almost drove me out of the room while at ~80 dB©.  If you listen to transients like snare or floor tom hits, you'll also notice a significant difference, IMO.

 

The key is to use one speaker only in the same place in the room if you can.

 

Chris

Edited by Chris A
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How did you figure out how high to set the output of the amps?  I am planning on having my Crown PS 200 pushing the bass bins and D75As running the mid/tweeter. Meter, ear? The Pioneer will EQ it in the end but I assume I want to have the levels somewhat close to begin with.

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You can use upsweeps and your ears to get very close.  You can also use a volt meter on the output of the amps - driving them at the crossover frequencies and checking their relative outputs.

 

If you've got TrueRTA or REW installed on a laptop, you can use the embedded microphone to check output levels just above and below the crossover frequency(ies). 

 

Chris

Edited by Chris A
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Two freeware programs that I really have gotten a lot out of: Audacity and REWTrueRTA is also very useful, albeit not like REW, at least for the things that I use it to do.

 

This article started me down the path: http://www.audioholics.com/how-to-shop/best-free-audio-software

 

Chris

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I don't have a preference on microphones since I use a Behringer ECM8000 and a small mixer to provide phantom power. 

 

Any calibration-type microphone that looks like it's fairly calibrated as-is without having to pay someone  to calibrate it separately is what you want.  You can check the AV forums online for this information.  The Behringer microphone that I have turns out to be really quite flat without equalization, which was a surprise, since it can apparently vary all over the map from lot to lot.

 

Chris

Edited by Chris A
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How did you figure out how high to set the output of the amps?  I am planning on having my Crown PS 200 pushing the bass bins and D75As running the mid/tweeter. Meter, ear? The Pioneer will EQ it in the end but I assume I want to have the levels somewhat close to begin with.

When we matched our setup...we ran a signal through the bass bins (REW internal test tones), and then with just the horns, then we matched the levels pretty close. To finish it off we used REW software, and ran the signals again (using the builtin tones)...overlapped both graphs, and adjusted the levels to give us the best response/crossover we wanted. Once we had that completed then we worked on fine tuning the delays. I hope I got this in the right order as it has been about 1 year since we did this.

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Well I finally had time yesterday to pull everything apart and set up the active crossover. I am using it on the front three 3  horns, with a passive crossover in the mix to let one channel do both mid and tweeter, while the second handles the bass bins (3 in, 6 out). While I am sure it needs tweaking the delay function certainly cleans thing up quite a bit, and the Ashly unit is very easy to use and figure out (which is good because instructions don't provide much help).  With a set up like mine this a nice set forward. Thanks to all who helped me get this going. 

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Next time I'm up that way, I'll have to swing by (with your permission of course).

 

We can share lunch at one of two places (that I have to go to whenever I'm up there)

 

One of course, is Skyline.  Other is Chesters Pizza on Rt 4 in Hamilton.  I'll let you pick which one you want to treat.

 

:ph34r:   :o   ;)

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Next time I'm up that way, I'll have to swing by (with your permission of course).

 

We can share lunch at one of two places (that I have to go to whenever I'm up there)

 

One of course, is Skyline.  Other is Chesters Pizza on Rt 4 in Hamilton.  I'll let you pick which one you want to treat.

 

:ph34r:   :o   ;)

You are welcome to stop by. Never been to Chesters before.

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  • 5 months later...

Tromprof,

 

I recently picked up the same crossover.  How did you set yours up?  What were the settings you started with? Such as output 1 hpf at 500hz going to your mid/tweeter and output 2 lpf at 500hz going to your q-pies.  Just trying to grasp the functionality of the unit vs Minidsp as things seem to be backwards.

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21 hours ago, The Dude said:

Tromprof,

 

I recently picked up the same crossover.  How did you set yours up?  What were the settings you started with? Such as output 1 hpf at 500hz going to your mid/tweeter and output 2 lpf at 500hz going to your q-pies.  Just trying to grasp the functionality of the unit vs Minidsp as things seem to be backwards.

I figured it out.  I didn't realize I had to set both the lpf and Hpf on all channels as they were set from the factory.  Music is playing and this Ashly is a big improvement over the minidsp.  Now I will use REW to tweak it a bit.  But first I must clean this mess up and finish my beer

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