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Crossover advice please


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I'm putting together some speakers which started out as a Cornscala project but has changed a bit since. I have ALK ES500 crossovers which I am still planning to use but I'm now thinking of adding a tapped horn below 90 or 100 Hz. I would like to use a passive crossover for this. Is there any way of doing this using some kind of generic crossover. I have Crites K33 clone woofers to use above 500 Hz and I'm thinking I may be able to use these in the tapped horns also. If no generic crossover will do, as I suspect is the case, where do I start with designing one?

Edit: Crites woofers to be used UP TO 500Hz.

Edited by Toon Army
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There are others here who are much more knowledgeable than me, but since nobody has jumped on this, I thought I would try to answer your question to the best of my ability.

First thing is you probably don't want to use line voltages for your crossover. The reason is the wattage difference between a power hungry tapped horn sub and a K-33 (100 watts rms), not to mention the squawker and tweeter.

What this means to me is that you need to be able to split the low voltage signal from your preamp to your amp, so you can send signal to a dedicated amp for the sub. many pro amps (like the Yamaha P series) have low pass filters and adjustments. This would be ideal for you.

If you wished to use an amp without those adjustments, you could design your own LPF to split the signal going to a monoblock. The best site I have seen for this is here: Analog Filter Wizard.

I hope I have helped.

Craig

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I just had some thoughts. Since you are likely listening in stereo, you will be needing to filter each channel independently. This means you will need 2 subs and 2 filters. You will also need to build a little attenuator into the setup to balance the volume between the speakers and the subs. This doesn't even bring phase and room mode issues into consideration.

My new advise is to buy an electronic crossover like this one: Behringer ULTRADRIVE PRO DCX2496. I have one, and can testify to it's abilities. Another device which would work is out of production. It is the Paradigm X30. It is an active filter and does have phase and attenuation built in. What I like about mine is that the adjustments are knobs rather than computer interfaces, etc.

Edited by mustang guy
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Thanks for your replies Craig.

The thing with the active filters like you suggest is that I wanted to use a different DAC. I know a lot of people are putting emphasis on room correction and ADC/DAC etc all in one place, but I wasn't planning on going down this route (at least not right now). I have been looking into this more (and had given up on this thread, lol) and thought a couple of hypex plate amps with built in filters could work for the tapped horns. I have a 211 SET amp, 30 Watts per channel, for the mid/tweeter do you think there would be any problem with this set-up?

Edited by Toon Army
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A plate amp is a brilliant solution, and is pretty much the same thing as the pro amp I mentioned adding a phase knob. The plate amps are active, however.

I just re-read your original post. You were planning on using K-33's in a tapped horn? MWM's were designed to use K-33's, so that speaks to their capability. Be aware they are 100 watt drivers. Are you using hornresp to design this sub, or is there a current TH sub you are looking at? What frequency are you hoping to achieve with the K-33's? Be aware the K-33's fs 27.9Hz and SPL~93db xmax 6.7mm or 34.46Hz and SPL~97db xmax 8.2mm depending on square or round magnet. They are very efficient and very competent drivers.

If you power the midrange and the tweeter with your set amp, how would you be powering and low pass filtering and attenuating your Crites K-33's in those cabs? Was it a typo saying you would be high pass filtering the K-33's in the Cornscala cabs? Are those what you were referring to as midranges?

Sorry, but this is so different than what I am used to, I may just have this all screwed up in my pea brain.

Edited by mustang guy
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Ok, sorry for the confusion. I was looking at passive crossover initially so I could use a separate DAC but have since realised I could use the Hypex units and still use my DAC of choice.

I want to use:

TH from 20Hz (or so) to 90Hz, possibly with Crites woofer but possibly smaller drivers as the TH for these is massive

Tractrix front horn from 90Hz to 500Hz, with Crites woofer

Eliptrac 400 from 500Hz up, with Radian 950

The ALK ES500 will be between the two front horns, with SET amp powering these, and the Hypex unit is now looking promising for use between the Tractrix and TH, powering the TH.

The Tractrix can be built for me by someone else with a talent for it. He already has a five way horn set-up using 15" drivers in TH (see http://www.hifiwigwam.com/showthread.php?54198-5-Way-horn-project-big-boy-system!).

The reason I asked here about passive crossovers is due to the fact he (speedysteve) has an active system and I know what recommendations I'll get on there :) (with good reason no doubt). As I already have some passive parts I was trying to keep it that way but anything is possible at this point.

Hope this makes sense, I've had no sleep yet and need to get to bed.

Paul

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OK, so you need to place a high pass filter before your ALK/Tractrix setup to limit at 90Hz and up. You just plug in 90Hz and stop at 45Hz, with -16db to come up with a -16db/octave slope. I'm not sure how this filter will affect the ALK. A call to ALK might be in order...

I was briefly looking at the Hypex plates, and their big amp didn't have high voltage in and out's. If the plate amp you choose doesn't have speaker level in, the SET will not be before the plate amp, it will instead be parallel. I'm not sure what splitting the line level to go to the SET _and_ the sub will do to the output of the preamp, but that is the only problem I can think of.

Edited by mustang guy
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I thought I could use the natural roll off of the Tractrix to help set the crossover point to the TH and use only a low pass filter. Seems I was being a little optimistic!

I want to use the following pre which states subwoofer amps can be paralleled on the output:

http://www.transcendentsound.com/Transcendent/Velvetizer.html

Edit: Just thought, I could add this into the mix as it acts as a high-pass filter:

http://www.transcendentsound.com/Transcendent/Sub_Buddy.html

Edited by Toon Army
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It's time for somebody who has a bit more knowledge than me to answer these questions. I know nothing about the transend brand. I also have no experience with natural roll-offs in lieu of passive crossovers. I know that it is done, but in my pea brain, the voltage is still being sent to the motor, so what is happening to the driver? Can't seem to wrap my head around that, so I can't help much there.

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It's time for somebody who has a bit more knowledge than me to answer these questions. I know nothing about the transend brand. I also have no experience with natural roll-offs in lieu of passive crossovers. I know that it is done, but in my pea brain, the voltage is still being sent to the motor, so what is happening to the driver? Can't seem to wrap my head around that, so I can't help much there.

That's ok, thanks for your time.

Bruce Rozenblit has answered some questions over on the Transcendent Sound forum re his Sub Buddy which I'll be able to use between DAC and amps. It will act as a high-pass filter to the SET amp and has outputs for subs with the plate amps having low pass filters.

Seems like I have a result \(",)/

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