First time OB builder

[Silent Screamer]

I currently have the crossover to the 10" at ~500Hz, but it is seriously lacking bass because of the low 88.5dB efficiency (compared to the 95dB Raal and 93dB mids in parallel).

I notice the 15's you have there are ~100dB mark which should give the bottom end some oomph. Should I use 1 or 2 15" per side? Do you find the single enough for bass heavy music?

Would I gain another 3dB by separate amps on the 4ohm drivers or remain at 93?

[studiotech]

Originally Posted by Silent Screamer

I currently have the crossover to the 10" at ~500Hz, but it is seriously lacking bass because of the low 88.5dB efficiency.

I notice the 15's you have there are ~100dB mark which should give the bottom end some oomph. Should I use 1 or 2 15" per side? Do you find the single enough for bass heavy music?

I run a set of sealed Rythmik Servo 15" to augment the B&C 15" below 60Hz, so I'm not actually sure how far you can push them. They will certainly need quite a boost the lower you want to run them, but I think a solid 40Hz might be possible. I like true full-range sound, so OB bass wasn't going to cut it for me.

When I was running the AE Dipole 15, they were not enough for me with bass heavy music at loud volumes.

[Silent Screamer]

Ok thanks that is definitely provides food for thought...

I basically have 4 channels to play with per side. I was thinking of perhaps making the OB bass swappable with separate subs for movies, but you are using them in conjunction.

So I could the RAAL tweeter, a pair of 12MUs (which ever config), something like the 15" your using, and a sealed or vented sub per side.

But if I am going with a separate sub do I really need to go 15" for the woofers?

[studiotech]

Originally Posted by Silent Screamer

Ok thanks that is definitely provides food for thought...

I basically have 4 channels to play with per side. I was thinking of perhaps making the OB bass swappable with separate subs for movies, but you are using them in conjunction.

So I could the RAAL tweeter, a pair of 12MUs (which ever config), something like the 15" your using, and a sealed or vented sub per side.

But if I am going with a separate sub do I really need to go 15" for the woofers?

Yeah, not many 15" I'd like to use up to 500 if I could help it, unless you want to spring for an AE Lambda TD15! Those are amazing drivers. Maybe a nice 12" would do the job. I really like the B&C because it measures well and has a small neo magnet and a nice, open aerodynamic frame. See some good measurements of larger woofer here:

https://sites.google.com/site/driver...r-measurements

I would certainly use a proper sub under 50-60hz unless you want to follow Stig's lead and have massive OB subs.

[Silent Screamer]

Just looking for full pictures of StigErik's system now...

Well I don't really need to cross over as high as 500 merely doing that to try get some more life out of the 10".

Take a look at the 12MU graph and tell me where you would cross over from the 12MU's to the 15" please.

[studiotech]

Stig's thread:

My open baffle dipole with Beyma TPL-150

Hope you have some time to spare! It's quite a journey and totally worth following every step! Epic...

You need to see how the 12MU measure without a baffle. You might get away with 350hz, but hard to tell without distortion plots while EQ'd to play that low OB. I run my B&C 15" up to 300hz no problem.

[Silent Screamer]

Thanks for that Greg, just found that same link while looking through the "Ultimate OB Gallery", seems in the world of OB, big is beautiful

[picowallspeaker]

Originally Posted by natehansen66

You need to think about the wavelengths involved. He's looking at crossing at 2k which is a wavelength of 6.75".

As far as woofer isolation, in my application the naked driver "scaffolding" is mounted to the u-frame, but the wire suspending the drivers hangs from rubber grommets. That plus the "swinging" action of the cable ensures little to no vibration transfer from the woofer to the upper drivers. They pass the touch test at least when the woofer is doing 40hz, which is as scientific as I'm willing to get here.

yes , I made a dipole last winter and readily disassembled it after one week .
The swinging and corruption from vibrations induced by the woofer wasn't
acceptable ( maybe because the mids and tw's were cheap stamped steel & plastic ) and I didn't like them on the floor , so I didn't investigate further
on how to 'put the patch' .
I recognize that suspending the speakers is the only way to eliminate mutual
interference . That applies not only to OB ...

[Silent Screamer]

Was just looking to see if the Raal could be converted to a dipole and low and behold they already make one that way...

Madisound Speaker Store

[Silent Screamer]

OK I'm probably pushing a visit from the men with the white suit that does up at the back, but what do you reckon to a couple of these?

$1000 a piece plus freight, but damn that response curve looks nice. One in each of the mains and another 2 in H boxes?