Can I run a 2nd order high pass with 4th order low pass?

[warnerwh]

My Cinenova amplifier has a second order crossover built into it. It would be nice to high pass my main speakers, VMPS RM 40s, at 55hz. Then I'd like to use a 4th order to low pass to the sub I am building with the Behringer cx2310.

My speakers have 1st order high pass filters. I don't understand how different crossover slopes interact. I am presently running my sub with a 4th order low pass and it is seamless.

Any help on understanding this would be appreciated.

Thank You

[JoshK]

Warner,

I am far from an expert on these matters, but do you have a means to measure? The important part is how the two systems combine acoustically (not electrically) *in your room*.

So I might measure the RM40's raw in your room down low. Then I'd add the high pass and see how that measures in your room and then add in the sub with low pass and go from there. I think it is possible to get good results, but I haven't yet read enough on filter summation to know how it will work without empirical results.

[warnerwh]

Josh: That's what I'd think too. I do have a way to measure my response and can adjust the Behringer DEQ 2496 for a smooth response but I've gotten the impression there's phase errors or something with a second order network. If there are errors it could be that down this low it wouldn't matter. Hopefully someone who understands crossover interaction will chime in.

I wonder too if I couldn't run a second order low pass being as it's already built into my amp. That would save me the cost of a crossover.

If you get to Portland again please let me know as you're more than welcome here.

[Habs4life]

Warner,
I use a set up similar to what you are planning and was able to achieve a good blend between my main speakers and sub.Depending on the F3 of your VMPS 40's your results will likely differ from mine but my main speakers woofers are ported and have an F3 of about 40hz.The woofers rolloff when combined with a 2nd order elecrical HP filter at 65hz results in an approximate 4th order HP response at 50hz ish.I use a 4th order LP filter at about 45hz for the subs.Some form of phase control will most likely be needed to get the best blend.A variable phase control (0-180 or 0-360)is preferred but a 0-180 switch will be helpful or you can just reverse the speaker wires on the sub.Proper phasing can be checked by playing some bass test tones and the position that gives the loudest bass is the correct one.

[ThomasW]

The 4th order L/R filters in the Behringer 2310 are likely the most phase coherent XO options you have available. So don't bother with the 2nd order filters built-in the power amps, use the 2310 for everything. It BTW has phase reversing switches.

[Habs4life]

So don't bother with the 2nd order filters built-in the power amps, use the 2310 for everything.

One possible drawback to adding the CX2310 to the fullrange signal chain is the introduction of objectionably hi noise levels.I don't know about this specific unit but many Behringers are known to be plagued with hi inherent noise levels.

[ThomasW]

I bought a 2310 to temporarily replace a couple highly modified Marchand MX9's that needed repair. I haven't gotten around to repairing the Marchands because there was no audible difference between the XM9's and the 2310. Somewhat odd considering the 6X price differential

I'm using a 2310 in a tri-amped system that has an Ayre K5-xe preamp and Ayre V5-xe and Aragon 8008BB power amps. So were it noisy I'd hear it.....

[Habs4life]

I'm using a 2310 in a tri-amped system that has an Ayre K5-xe preamp and Ayre V5-xe and Aragon 8008BB power amps. So were it noisy I'd hear it.....

Yes with that caliber of gear you certainly would.

It is good to know that not all of their units are noisy but I find it a bit surprising that the 2310 equaled the XM9 considering that you probably built your Marchand with superior low noise Opamps (OPA2134's?)compared to what are in the Behringer.

My only Behringer experience is with the BFD.I have a quad amplified active system using a combo of Bryston 2Bs and 3B's,and a Pass DIY preamp. I recently borrowed a BFD to do some experimenting with EQ and found that it had very hi noise(not hum)that was audible from several feet away from the speakers when used in the 50-300hz channel of my system.Although it was unuseable for the higher frequency range the noise was not intrusive when used in the sub channel.
I have also heard reports of other Behringers with noise issues.

[ThomasW]

I use BB-OPA2604's in my XM9's, they're better for the longer cable runs I use.

And yes I was shocked when I put the 2310 in the system. I expected it to provide barely tolerable performance while I repaired the Marchands. Instead there was no audible difference....go figure... 8O

[warnerwh]

I think I might as well get one. It will make life easier and give me more versatility. I really don't like the idea of low passing my subwoofer with a 12db slope. 24db will eliminate any problem and I can high pass my mains at 40hz I bet without any audible anomolies.

I have alot of confidence in Behringer's equipment. My DEQ 2496 has been all good so I've got no apprehension of using a crossover of theirs especially when you consider it will only be used for the subwoofer.

[ThomasW]

The DEQ2496 is a different animal from the Feedback Destroyers. I exchange emails with the director of marketing for Behringer of North American. He said that only the DEQ2496 specifically designed and built to be a high quality fullrange EQ.

I've read on a couple forums where people are placing them between the digital out of their CDP/DVD players and their outboard DACs. Apparently this provides even better SQ than using them in the analog feed. So one of these days there's another experiment to try.....

[Scott Simonian]

Yeah....it's 2006. Almost 2007, now. Still no 5.1 digital EQ's in a affordable price range. Hmmm....

[warnerwh]

Yeah....it's 2006. Almost 2007, now. Still no 5.1 digital EQ's in a affordable price range. Hmmm....

Just buy 3. They're less than 2" high and not very deep. For HT I wouldn't worry about adding an outboard dac as the AKM 4393 in it is pretty good. For HiFi though I use an outboard dac.

Thomas: There's no degradation I can detect from using the DEQ 2496. Only the upside of being able to adjust the amplitude response closer to ideal and also to your taste. Even in my fully treated room with bass traps my response is still plus or minus 10db which is much better than the average room. Even if you use 15db of adjustment the phase error is 5%. At least this is what one guy measured over at Audiokarma. Compared to analog equalizers this is truly inconsequential.

The real beauty though is what you can do with your bass response. That is where most of my parametric bands are being used.

The other day I was talking to Ethan of Realtraps and he said typically he measures about 6-8db peaks and nulls of 25 to 30db in the average rooms of homes! That's alot. More than enough to seriously screw up your sound.

For what the Behringer units cost they're true bargains and reward you well with their performance and I will even say quality. I've talked to two engineers, one an amp designer and Dusty who owns Channel Island Audio and both told me how impressed they were with the quality of parts and build in these units for the money. They said they wish they could offer so much for the money.