[Russell Dawkins]

this new 21" speaker from B&C looks tasty:

http://tinyurl.com/2b2rxh

How does 21" diameter, 2.5" peak to peak max excursion, 6" voice coil, 1500W continuous, 95 dB/W/M

B&C are not too expensive, either. This model is so new it doesn't show up on their website, but the enclosure does.

[Brad]

Yeah, but how are you going to get 1500wpc out of a 45 or 2a3 tube?   

21" with that kind of excursion, that is MOVING some air

[Russell Dawkins]

tubes? No, this is ICE amp territory, maybe 300 Hz and down. Seems like it would be a good idea to bolt the speaker down, though, and brace the back if it was an open baffle.

Actually, I wouldn't be surprised if all these open baffles with the big drivers wouldn't seriously benefit from a diagonal brace from a point about 2/3 way up the back down to the floor - ideally the wall/floor junction.

Quad finally did it with their latest model and it was probably only aesthetic considerations that prevented them from doing it before, because every model from the '63 on would have benefited.

[Russell Dawkins]

Seems like this Selenium 15 has risen to the top for OB use ($60 ea in 4 lots):
http://tinyurl.com/2qdhmb

people on OB threads in "other forums" are very impressed and are saying things like:

"I did what I should have done to begin with, I ordered 4 Selenium 15PW3-SLF 15's from Parts Express. I (am) running them in a bi-amped system on ~24 x 32 U baffles with 11" wings. They have completely exceeded my expectations. They are extremely agile, beautiful tone and clarity with tremendous power and delicacy"

[Bob in St. Louis]

Some here may disagree with me, I don't believe the open baffle will give the deep bass you can get from a vented or sealed box.

You're right.
Well, about the disagreeing part of it I mean. 
But I suppose the definition of "deep bass" is open for debate.

Bob

[nodiak]

Michael, I know you said you didn't want to go active...but...what about plate amps fed from the speaker level of you're tube amp? I'm doing that with great results. It is more money, but I've scoured the garage and shelves for stuff to sell to make up the $ difference.
Of course there may be a satisfying passive solution with the right woofers. If you only need 35 hz it seems they are out there somewhere. Room placement could help alot too. Anyway, good luck with it. 

Bob, Debate? 10 hz is lower than 20 hz, $5 is more money than $4, 2 miles is farther than 1 mile, etc. 
I've used the Augies and really like them alot, but am more satisfied with sealed Rythmik sub in my system/room. The Rythmik goes deeper, but the Augie has more character/warmth where the Rythmik is more clean. In a different (bigger) room I could see me going Augies and IB subs, could be great. IB is probably the ultimate, would go lower and cleaner presumably, just need more drivers for power handling (wish i could do it here).
Different approaches for different tastes/situation$. These are different tools to use for different purposes. 
The new GR Research OB subs have both the openess of OB and the control and depth of Rythmiks servo system - and will cost ~ $1200 for 2 woofers per side and 2 amps. A stretch, but might be worth it, checking for stuff to sell...
Don

[Bob in St. Louis]

Understood Don, it's all good. I was questioning what ttan said about 'deep' because the comment was made about the quantity of bass created by OB vs other forums. What one fella may call 'deep', another fella may call wimpy and yet another may call overkill.
No problems though. 

bO.B.

[Michael V]

Hey Don - hope you are well.  I will send you a PM today.

Active bass augmentation is the perfectly logical solution, I know.  Right tool for the job, etc.  I tried my plate amps with both the Augies and SI woofers, and whereas the SI woofer sounded much more coherent and defined than the Augies, I couldn't live with either setup.  The Augies - in any configuration - didn't extend deep enough or exhibit anywhere near enough control to justify a seat at the table.  (yet they still sit in my closet...)

I tried driving the plate amps from the main power amp as well as my preamp.  The former was more coherent, but sucked the life out of the music.  The latter retained musicality, but bass integration was always an issue.  I know the impedance in both setups should be benign, but for whatever reason I am really sensitive to biamping, and for the moment I want to see what I can do passively.

Of course there may be a satisfying passive solution with the right woofers. If you only need 35 hz it seems they are out there somewhere.

Exactly!  

Maybe the easier solution is a BR subwoofer cabinet located behind the speakers near the wall - which would be driven by the main amps.  I can't think of anybody offering high-eff subwoofers, but maybe it's workable?

[ttan98]

Some here may disagree with me, I don't believe the open baffle will give the deep bass you can get from a vented or sealed box.

You're right.
Well, about the disagreeing part of it I mean. 
But I suppose the definition of "deep bass" is open for debate.

Bob

Personally I am not a bass man myself, like others who cherish in deep bass, that is why I give an example about CS2. As far as I am concern twin 15" woofer which is also equalised is  good enough for me even though I have not heard CS2 before( I have heard twin 12" woofer in Uframe, the bass is good enough for me). CS2 owners have the option to buy additional subwoofer to complement the speakers, those buyers I would consider deep bass fans.

[nodiak]

Hey Michael, I'll look for the pm, hope all is well. (Btw, my regular email isn't working so pm is only way to reach me).
The Selenium Russell pointed out looks good. Also maybe you can find some 16 ohm bass speakers...maybe. Then you could parallel 2 per side for 8 ohms and high eff. Might mate with B200's passively. Maybe a stroll thru ebay?
I haven't kept up with Lynn Olsons diyaudio OB thread ("Beyond the Ariel"), but there must be alot of good ideas in there.
Do you have any U frame solutions in the works? I never finished a U frame project I started so didn't learn about them, but seems like a good direction for your situation. One driver, low to the ground, B200 on top at ear level, maybe a cap and coil xo would work.
Bob, we're always good from my end. But if you know of a driver that gives more/lower bass on OB than in a box we want to know!
Don

[Grumpy_Git]

Michael

It sounds like you have B200s, SIs, Augies and plate amps. whay not use them all?

B200s and Sis as they stand and the augies on plate amps as subs?

Nick.

[Michael V]

It sounds like you have B200s, SIs, Augies and plate amps. whay not use them all?

B200s and Sis as they stand and the augies on plate amps as subs?

Nick.

Nick - thanks but as I've stated, my goal is a passive solution for the deep bass.  i.e. no bi-amping.

[tubamark]

It sounds like you have B200s, SIs, Augies and plate amps. whay not use them all?

B200s and Sis as they stand and the augies on plate amps as subs?

Nick.

Nick - thanks but as I've stated, my goal is a passive solution for the deep bass.  i.e. no bi-amping.

Then padding down the B200, or using Multiple augmentors is about the only option for OB.  Note that in MJK's latest article he frankly states that he had painted himself into a corner (on the huge double 15 OB) the very moment he chose a sensitive lowther driver.  In his second OB opus he went with a better matched Fostex and was plenty happy with the results + improved footprint/SAF.

It really wouldn't be a crime to just try a pad on the B200.  Or try two 15's on the sides of a U-frame (nothing on front), opening on the rear sized to perhaps 50% of total cone area (A 14" hole would be about right, & damped.  This would allow a reasonably narrow front panel, and buys you +6 more db on the bass.  This loading should also buy you a couple more Hz of bass extension (but only a few - this is not Ripole loading, which is really inefficient)

Just a thought.  It's all about tradeoffs.   Size, Efficiency, Extension.  You only get to pick two . . . and always at the expense of the third.  No design to date has proven different.

-- Mark

[Bob in St. Louis]

Bob, we're always good from my end. But if you know of a driver that gives more/lower bass on OB than in a box we want to know!

I only have one driver in mind Don. I stopped looking for drivers a couple years ago. It's been awhile since I've taken readings, but I'm well over 100dB going down low enough for anything Hollywood can dish out. In my (very) humble opinion that's low bass.   aa

Bob

[navin]

That's a possibility - the so-called WWF arrangement - but the upper woofer is still 16" from the floor boundary.  Since I'm concerned with getting the last octave the driver is capable of, wouldn't that amount of floor bounce cancellation mitigate a WW's benefits?

Why wouldn't an 18" driver be ideal?  If the Warrior's specs are 'optimistic', then what about some of Eminence's offerings that should be closer to their published sensitivity and Fs? 

To put it another way, is there a single bass driver that would meet all my (admittedly high) requirements?  Sensitivity to match the V200, bass extension flat to 35-40hz, and can be passively integrated with the WR driver on open baffle.

Thanks for everyone's input!

actually in my book having 2 drivers vertically stacked compensates for floor bounce over a wider range.

If you want to use 1 woofer I would cosidner a home audio equiavalent of this woofer (car audio woofers tend to have high Qts which works for OB).
http://www.cardomain.com/ride/2249624

[navin]

tubes? No, this is ICE amp territory, maybe 300 Hz and down.

or this amp
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=300-808

[Michael V]

If you want to use 1 woofer I would cosidner a home audio equiavalent of this woofer (car audio woofers tend to have high Qts which works for OB).
http://www.cardomain.com/ride/2249624

Thanks - I'm not stuck on using 1 bass driver, but getting enough extension with 1 would be great. 

21" sub?  Now we're talking.

[navin]

try two 15's on the sides of a U-frame (nothing on front), opening on the rear sized to perhaps 50% of total cone area (A 14" hole would be about right, & damped.

Would you have a sketch. I would like to know if we are on the same page.

[Michael V]

Then padding down the B200, or using Multiple augmentors is about the only option for OB.  Note that in MJK's latest article he frankly states that he had painted himself into a corner (on the huge double 15 OB) the very moment he chose a sensitive lowther driver.  In his second OB opus he went with a better matched Fostex and was plenty happy with the results + improved footprint/SAF.

It really wouldn't be a crime to just try a pad on the B200.  Or try two 15's on the sides of a U-frame (nothing on front), opening on the rear sized to perhaps 50% of total cone area (A 14" hole would be about right, & damped.  This would allow a reasonably narrow front panel, and buys you +6 more db on the bass.  This loading should also buy you a couple more Hz of bass extension (but only a few - this is not Ripole loading, which is really inefficient)

Just a thought.  It's all about tradeoffs.   Size, Efficiency, Extension.  You only get to pick two . . . and always at the expense of the third.  No design to date has proven different.

-- Mark

Fair enough, but I'm willing to give on size to get that last octave or so.  Thanks for the mention of MJK's article on dual 15's, I'll have to read about that design.

Sensitivity is very important to me- so much so that padding down the B200 would be criminal.

I'm curious about the side-firing 15s on a U (is that still a U, by the way?) - are you aware of any implementations?

[nodiak]

Seems it would be worth studying the dual/opposed side firing drivers possibly (ok probably) being a problem with fr, room response and imaging since Michaels trying to get to 200 hz?
Any experiences to share with single stereo U frames? Seems really interesting.
I did use B200 padded down to mate with Augies, was powerful and dynamic stuff, but I felt they needed some watts and used a chip amp.
Don

Hi Bob my true friend, the point was a given driver on OB has a 6db drop off in bass compared to in a box. Nothing to do with brand. Didn't you find your drivers had more/deeper bass in IB than OB?