Drivers, Active XO & EQ for Dipole Bass?

[LoudandClear]

Hello!

This is my first post (long time lurker though). Lot's of great info here!

I'm planning on building a dipole bass "section" to support my experiments in OB speakers. I am currently using Visaton B200's in OB and would like to add dipole woofers to them. I have read the Avro HM thread and would be building a woofer section similar to that (no H/U/W/N/V frame to start). I would build the bass section with the baffle split from the upper section so that I can keep the woofers intact and "play" with other arrangements (ie MTM or MT or MMT) on top. I would like to use active EQ & XO on the woofers so I can dial them into the room and whatever drivers are on top. This may mean XO as high as 200hz (will settle for 120hz if I have to)

I have read here that the Behringer DSP1124P Feedback Destroyer Pro (BFD) is very useful for EQ for subs. I was orignally considering plate amps, but like the flexibility of the BFD & seperate power amp (ie Nady, Behringer, QSC, Crown etc)

My first question, is the BFD usable for active EQ & XO duties for dipole bass or do I need a seperate XO as well?

Next question. Which Drivers???? They will need to be able to play clean fairly high I think (somewhere 300 to 800hz???) and I would be happy with bass response down into the 30's or 40's. We live in an apartment so huge SPL's are not required. Am I asking for too much here? From what I read, I need a mix of high excursion and low inductance/

I am thinking either 2x10" or 2x12" per side and have come up with the following list:
Peerless XXLS
Dayton RS HF
TC Audio Tc2+
Soundsplinter RL-p12
Elemental Designs 110v.2 or 130v.2
Stryke AV12mkII
Ascendent Arsenal (ETA? - the Atlas with vari-Qts looks interesting but it looks to be end of life)

The Dayton 15"IB driver also looks intriguing with is high qts but I don't know how clean it is above 100hz.

It sounds like some of the driver suppliers can be a bit "tempermental" and I would like to avoid "servicing" issues.

Any thoughts here would be very much appreciated!

Thanks . . .

[ThomasW]

The BFD is EQ only. You can add a Behringer CX2310 for $90. Another option is the Behringer DCX2496, it's EQ and a crossover. It's more $ and much more complicated to use.

The TC2+ and the RS drivers will do better up to 200Hz.

The problems you refer to are solved (1/2 the problem was the supplier, the other 1/2 was improper measurement techniques by the purchaser). Servicing issues will be eliminated with Deon B. coming on board, and a new shipment of product from the far east (February arrival I think). The IB-15"s are one of the best deals in audio today. I think you can still special order drivers with the phase plug.

[LoudandClear]

Thanks Thomas.

I was also starting to get excited about the Velodyne SMS-1 sub eq system because is has XO facilities as well except it appears to sum the input channels into one to feed up to three subs (the same mono signal). What is up with that (I hope I am wrong)

[ThomasW]

From the limited exposure I've had to the SMS-1 (an IB sub builder has one), they appear an overpriced, limited performance device for what they do, or in his case don't do. They aren't 'smart' and can't solve room related issues. That combined with only 8 bands of EQ make them an unattractive purchase compared to the much less expensive competition (things like the Behringer components I mentioned my first post.

[LoudandClear]

Thanks Thomas.

So, do we go with 10's or 12's????

[ThomasW]

I'm busy this AM and will get back to you later.

In the meantime, have you seen this?

http://www.visaton.com/english/artikel/art_829_6_20.html

[LoudandClear]

Yep, I ve seen the "NoBox" a few times. I don't care much for the looks. The XO frequency @250 is probably higher than where I want to be, especially with sub drivers I'm considering.

[ThomasW]

So, do we go with 10's or 12's????

Probably 12"s to get the output up.

We have the RS HF 12"s, but haven't had the time to test them. On paper they look better than the TC2+, given the Le of .95mH.

[sfdoddsy]

I've used all the Behringer products discussed and have them in different parts of my system now. It's trickier EQing a dipole sub with the Feedback destroyer because of dipole rolloff and some other dipole specific issues.

The DCX isn't that much more expensive than an FBD/CX combo and is much better suited to what you are trying to do. The software makes it a doddle to use.

Cheers

Steve

[LoudandClear]

Steve,

Thanks for the response relating to XO & EQ. My concern with the DCX (or any other digital XO/EQ) is that the added DSP latency will cause a noticable issue with "time alignment" of the bass and mids as I do not want digital EQ/XO on the full range mids.

I have contacted Rane to see what there suggestion for an analog EQ/XO for dipole bass would be.

Can you share with us how much db of gain and across what frequencies is generally required on dipole bass similar to what you have implemented?

[sfdoddsy]

The Behringer allows you to time align your speakers should you desire.

Below a certain point (which varies depending on drivers and baffles), dipole bass rolls off at 6dB an octave. Assuming this starts at 200Hz, for example, your speakers will be 20dB down at 20Hz, so your equalizer needs to be able to supple to appropriate boost. Linkwitz EQs his designs down to 5Hz or so, requiring a 40dB boost.

The DCX can handle this EQ by overlaying shelving filters, the other digital EQS arn't quite as flexible.

Cheers

Steve

[AJINFLA]

And then there is this: http://www.lautsprechershop.de/hifi/...i/sub12_en.htm
The Sitronik D series. Not cheap and yes, thats Euros, so you would have to import it, unless someone knows something similar available here stateside.



Cheers,

AJ


edit: bad link, go to "Active Modules", "Sitronik" from home page

[LoudandClear]

@Steve
The problem with the Behringer is that I would not be using it on my mids/highs so its DSP latency will throw off the time alignment for the bass that can not be adjusted for (ie there is no setting to "speed up the signal").
Thanks for the reminder on the dipole roll-off equation. I should really re-read linkwitz.

@AJ
looks like a nifty plate amp. It probably won't work for me. I have to wonder what the latency is and there appears to be only 6db of gain available on the EQ which will not be enough.

I am now thinking that the solution is to get the Behringer to experiment/model/test XO/EQ solutions (using it full range) and then build active or passive XO and EQ's matching the "ideal".

I will continue to watch the ARVO project as it develops.

Thanks everyone for their input . . .