[JoshK]

How about 2 Selenium 12PW3's per side?

[Saurav]

Selenium 12PW3 - I'd seen that one when I was looking through the 12" drivers at PE, but didn't really look for more info on it. Have you used this driver? Will it work with a 400Hz XO?

Peerless SLS 830668 - I'll have to look that one up too.

Thanks for the suggestions.

Edit: Just looked at the Selenium, OK, so it should work with a high XO.

I think it fundamentally comes down to - do I go with a high Q / high eff / low Xmax driver, or a high Xmax / low eff / likely low Q driver.

[Dmason]

If you power them with inexpensive plate amps also from PE, you can make low Ef., high Xmax drivers work just fine. Better, IMO, because they will move more air, given that you require a 12 to do the job, this is your best route... it opens the field to a bucket load of 12 inch drivers. PE has good quality plate amps, a couple of which sport 200Hz LP, which makes them OB-approved. For a hun, it dont get any better. Jus' my opinion, dontcha know...

[Saurav]

I have a Behringer A500 that I was using as a sub amp, I think I'll be using that on the woofers and probably buy a BASH or something for the sub. I haven't really done enough listening comparisons to have an opinion on this. I had a hi-eff woofer once, and there was something about how lively it sounded that I can't forget. But I've never really tried a low-eff woofer that has good Xmax and is driven by adequate power, so... I don't know. It'll probably sound as good.

[JoshK]

Martin King last I heard was doing a study on the two approachs (as Dan outlines) to doing OB woofers.  There are tradeoffs and benefits to either.  Pick your poison.  I have heard the high Qts, high Fs, low xmax implementation before and didn't care for it, but it could have been specific to the implementation. 

Myself, I am trying to straddle the fence, sort of speak, but using a modestly high eff, medium high xmax, lowish Qts, low Fs woofers (15 TDX's).  I want to keep efficiency up while admitting some eq. 

[Saurav]

OK, the hi-eff woofer I had was in a sealed cabinet, so you make a good point, I haven't heard what that sounds like on an OB. And with an active XO I have the option of using lower eff / higher xmax drivers, since I don't need to match the efficiency of the midrange.

It'll be interesting to see Martin's results. I downloaded some of his worksheets a few days ago and have been playing with the "midrange + 2 woofers on an OB" one. Some early sims are posted in a thread on HTGuide.

[Saurav]

Still researching

Would the Peerless 830668/830669 work with a 4-500Hz XO? Are nearfield measurements of these drivers available anywhere (other than the ones from the manufacturer)?

I found some measurements of the Eminence Alpha15, and it starts to get a little ragged by 500Hz.

[WerTicus]

Look at the new GR research woofer, they have a circle here.

I just got mine in the mail today - they are certainly the business, and servo controllable

this is a subwoofer btw... 15 - 150hz or so

[ttan98]

Look at the new GR research woofer, they have a circle here.

I just got mine in the mail today - they are certainly the business, and servo controllable

this is a subwoofer btw... 15 - 150hz or so

Not only you have to pay for the woofer, you have to add in the price of the special servo controller.

BTW how much you pay for the pair of woofers plus servo controller?

[WerTicus]

the sevo controller is part of the amplifier - woofers are 150 each and servo amp is 279  usd +shipping

[panomaniac]

I believe you want to get the freq to go down to that region you need low Fs as well as high Qts>=0.7, if you cannot get qts >=0.7  then you need U or H frame. I also believe you want open baffle bass then you need 2 woofers not one connected in parallel.

Quite agree!  Qts>0.7 is going to make your life easier.  As well as low Fs - not easy to find in a 12".  Though I have heard the Peerless on OB and liked it.

The big problem with OB bass is the crazy rising response - or lack of bass, if you want to look at it that way.  So you gotta do something.  You can do as Marin does and use 2 big, high Qts drivers and big baffle to help the low end.  On a small baffle with a small driver- good luck!  You'll have to EQ the hell out of it or low pass filter it super low to fight the rising response.  Either way, you're trading away efficiency, lots of efficiency.

Then there is the problem of getting the wide range driver to play down low enough.  On a mid size baffle like I use (or as used by the infamous "Lampizator) your wide range drive is likely to start going south under about 300Hz.   Sooooo, you have to get the 12 or 15 to play up that high and higher, even with the EQ for the lackof bass!  Not easy.   

What is easy is to end up with a hole in the middle, too hot midrange, no bass at all or any of the above.

[ttan98]

the sevo controller is part of the amplifier - woofers are 150 each and servo amp is 279  usd +shipping

Thanks, 2 more questions:

1. you need 1 amplifier for 2 woofer or 2 amplifiers, i think it is the latter.
2. The highest freq., the woofer will x-over

[opnly bafld]

the sevo controller is part of the amplifier - woofers are 150 each and servo amp is 279  usd +shipping

Thanks, 2 more questions:

1. you need 1 amplifier for 2 woofer or 2 amplifiers, i think it is the latter.
2. The highest freq., the woofer will x-over

1. up to 3 drivers (16ohms each) per amp.
2. the highest x-o is at 150hz/12dBs oct (on a thread somewhere Danny mentions how high they can play).

Lin

[Saurav]

this is a subwoofer btw... 15 - 150hz or so

I'm looking for a woofer to cover from 80Hz to 500Hz, so this does not help me. This is because I want to use the midrange driver I'm currently using. If I upped my budget to include new drivers, then I'd probably design this differently, and there are many woofer/subwoofer options available that are usable with a 150-200Hz crossover.

The big problem with OB bass is the crazy rising response - or lack of bass, if you want to look at it that way.  So you gotta do something.

I'm prepared to use EQ for that if required, and as I said, I don't mind switching to a monopole subwoofer below 80Hz, so I only need bass down to 80Hz. I looked at the Alpha15, and I'm not sure how clean it will be up to 500Hz. IIRC, Martin's design crosses over from the 15" to the fullrange Fostex at a lower frequency.

[Vapor Audio]

I'm currently leaning towards a pair of Dayton RS270's, they look clean up to 500Hz and higher. The high XO also mostly rules out U and H frames, so I'm modeling these on flat baffles to see what I get.

You want to stay farter away from the breakup than that.  The Dayton aluminum drivers have NASTY breakup nodes, not so much on paper, but they're painful to listen too.  400hz maybe, but cut it off sharp if you go even that high.

BTW, what midrange are you using?  Not sure why you think you need a woofer to go to 500hz.

[Saurav]

An Audax PR170M0, which has 0.5mm Xmax, and a manufacturer recommended XO of 18dB @ 600Hz. I've used it with LR4 down to about 400Hz on an OB, and it sounds fine, but I don't want to go too much lower than that.

http://www.hautparleur.fr/_audax/pr170m0b.jpg

http://www.hautparleur.fr/_audax/pr170m0.jpg

If I upped my budget by a 2-300 bucks and picked up a PHL/B&C/Beyma midrange, then that would probably make the job of finding a woofer a lot easier.

I'm not really thinking of the 270s any more. A modified AE IB15 (with reduced mass) is an option, it gets a little ragged by 500Hz, but not really any worse than the Alpha15. It will require more EQ, of course. The Peerless 830669 might work too, but I haven't seen any measurements besides the ones from the manufacturer.

[Vapor Audio]

An Audax PR170M0, which has 0.5mm Xmax, and a manufacturer recommended XO of 18dB @ 600Hz. I've used it with LR4 down to about 400Hz on an OB, and it sounds fine, but I don't want to go too much lower than that.

http://www.hautparleur.fr/_audax/pr170m0b.jpg

http://www.hautparleur.fr/_audax/pr170m0.jpg

If I upped my budget by a 2-300 bucks and picked up a PHL/B&C/Beyma midrange, then that would probably make the job of finding a woofer a lot easier.

I'm not really thinking of the 270s any more. A modified AE IB15 (with reduced mass) is an option, it gets a little ragged by 500Hz, but not really any worse than the Alpha15. It will require more EQ, of course. The Peerless 830669 might work too, but I haven't seen any measurements besides the ones from the manufacturer.

Gotcha, and agreed on the Audax ... it definately needs a high cross.

Keep in mind though, 500hz is firmly in the middle of the vocals, and really just about everything important in music.  That's a dangerous area to crossover, and it's even more dangerous when you're talking about going from a (relatively) slow sub to a (relatively) fast driver like the Audax.   Integrating the two will be tough, even more-so on a flat baffle, the woofer response will probably be about 2 full ms behind.  You can get away with delay like that in the 150hz area, but less so at 500hz. 

I kinda came in late, but is high sensitivity a goal here?  And what tweeter are you planning on using?

... edit, see you're using a Fountek JP3.0.  Since you're doing active x-over, why not run it down to about 1500hz and cut it off hard ... it can handle that.  That opens up your midrange choices, many 8" drivers can go up to 1500hz with no problem.  And you could go with any number of Seas/Peerless/Scan 8" woofers and get close to 90db sensitive.  And go down to 150hz easy.

[Saurav]

This thread is pretty out of date

I have a pair of BMS 4540NDs, and a pair of XT1086's should arrive today. If the threaded/bolt-on mismatch isn't too bad (and it probably will be, which means I'll probably switch to a bolt on CD), then that's what I plan to use. That can go down to say 1500-2000, I think.

High efficiency is a goal for the upper panel (mid+tweeter), not the woofers. I'll be running these off a 4W SET, so 90dB isn't enough. 95+ at least, 97+ would be best. The normal choices for 8" woofers/midwoofers won't work, some of the pro ones might.

[Vapor Audio]

This thread is pretty out of date

I have a pair of BMS 4540NDs, and a pair of XT1086's should arrive today. If the threaded/bolt-on mismatch isn't too bad (and it probably will be, which means I'll probably switch to a bolt on CD), then that's what I plan to use. That can go down to say 1500-2000, I think.

High efficiency is a goal for the upper panel (mid+tweeter), not the woofers. I'll be running these off a 4W SET, so 90dB isn't enough. 95+ at least, 97+ would be best. The normal choices for 8" woofers/midwoofers won't work, some of the pro ones might.

Ahh, well I think you might be surprised how low that combo could go ... I wouldn't be surprised if it would do 1200hz well with a sharp cutoff.  And yea, it sounds like you're pretty much limited to pro-sound for the mid.

[MJK]

An Audax PR170M0, which has 0.5mm Xmax, and a manufacturer recommended XO of 18dB @ 600Hz. I've used it with LR4 down to about 400Hz on an OB, and it sounds fine, but I don't want to go too much lower than that.

http://www.hautparleur.fr/_audax/pr170m0b.jpg

http://www.hautparleur.fr/_audax/pr170m0.jpg

If I upped my budget by a 2-300 bucks and picked up a PHL/B&C/Beyma midrange, then that would probably make the job of finding a woofer a lot easier.

I'm not really thinking of the 270s any more. A modified AE IB15 (with reduced mass) is an option, it gets a little ragged by 500Hz, but not really any worse than the Alpha15. It will require more EQ, of course. The Peerless 830669 might work too, but I haven't seen any measurements besides the ones from the manufacturer.

I guess I don't understand the concern or need for a bass and a midbass driver below the Audax. If you selected a high Qts woofer and designed a baffle such that the electrical crossover was at approximately 200 Hz, then the acoustic crossover would probably be at 300 or 400 Hz. Then you use your Audax midrange and design the electrical high pass crossover to be a little higher (maybe 400 to 500 Hz) to provide a compatible acoustic crossover. When I did this in the two sample problems that are the defaults for my MathCad OB worksheets, the displacement of the full range drivers near the crossover point was approximatly 0.05 mm for 1 watt of input. It would seem logical to me that a woofer, or maybe woofers, and your midrange driver should be able to work together and not have the Audax be anywhere near the Xmax of 0.5 mm. You could use your midrange, not worry about Xmax, and still avoid the break-up modes of the woofer. I don't see any reason to spend more than $75 per woofer, there are a few options that should fit the application and provide decent bass to 40 Hz.