Dual Reflex Bandpass cabs!

[Merton]

OK, here's the thing. I have a spare 15" driver - a Celestion Q15-2550 I believe, no longer made - which needs a "box" to go in I was originally thinking I'd build an Omni 15 of some description, but I had a stupid thought last night - what about doing a Dual Reflex Bandpass cab like the old Trace BLX combos, just for a giggle?!

So the question is, how should I go about designing one (I don't thnk WinISD has this type of design in it...)? Any other software or info on the calculations needed? Alex, I'm looking at you! [i](I have to confess I have done zero google searching so far on this, must try harder)[/i]

I suspect the driver in question may be totally the wrong choice for the DRB type of cab. It was in my first home-build cab and that was rubbish as I made the cab too small - I ignored what the numbers said in a vain attempt to make it match the 4x10 I had at the time... Oh the stupidity of youff! I've finally ripped the cab apart after having it take up room for 5 years, I'm using the metal grille to re-inforce the cloth grille on my V-Type 1x15 combo (it will sit behind it) and the speaker currently looks like a weird fruit bowl in my living room so I want it to go in a new box.

Is the Dual Reflex Bandpass cab a stupid idea? Discuss: pros, cons, calculations etc

[Bill Fitzmaurice]

WinISD will do dual chamber bandpass reflex, but you have to tweak the parameters manually. It's probably the least useful cabinet type for MI use as it has a very narrow passband and is extremely fussy to realize. It also demands a full crossover, by either bi-amping or passive, both being expensive propositions.

Edited March 3, 2008 by Bill Fitzmaurice

[Merton]

Cheers Bill! I just realised WinISD does do these cabs, was relying on my fuzzy memory rather than pure fact.

But that aside, it's prob a bad idea all said and done!

[alexclaber]

Exactly what Bill said! I recently tried modelling a whole pile of reflex, bandpass and sealed cabs with the 3015LF and a straight forward reflex box comes out very well. You can get a smidgeon more output from a bandpass cab but to do so you have to drastically narrow the operating range which means you end up carrying more gear anyway...

Alex

[Merton]

Omni15 of some flavour it is then

[TheRinser]

I've got 2 of those drivers in my 2x15! it's over a metre tall (i think 120 or 160cm...) and sounds alright at low volumes, but crap at anything like gig volumes. crap xmax if i remember correctly? dr decibel (he even had business cards!) from celestion helped me design the cab, porting, volume etc. Do you have the parameters for the driver? i've lost 'em and i'd love to try and make a good cab out of them. if it's possible. bill?

[Merton]

[quote name='TheRinser' post='150561' date='Mar 3 2008, 06:47 PM']I've got 2 of those drivers in my 2x15! it's over a metre tall (i think 120 or 160cm...) and sounds alright at low volumes, but crap at anything like gig volumes. crap xmax if i remember correctly? dr decibel (he even had business cards!) from celestion helped me design the cab, porting, volume etc. Do you have the parameters for the driver? i've lost 'em and i'd love to try and make a good cab out of them. if it's possible. bill?[/quote]
I have asked said Doc coz I've lost all the specs. Will copy them on to you if/when I get them.

I suspect it's a better mid driver for PA apps rather than a dedicated bass driver, in which case it may stay as a weird fruit bowl type ornament in my living room!

That said, I blew one of the 8" drivers in my 4x8 combo yesterday so getting replacements for all 4 means I'll have 3 spare 8s kicking around, [i]begging[/i] for an Omni15 build!