|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
220.244.218.142
In Reply to: RE: High efficiency + sealed cabinet? posted by vetmedrobert@gmail.com on March 25, 2014 at 16:09:20
I'd look for big drivers with Qts of about .4-.5 and lowish Fs
Not many pro / HE drivers fit this. 15-18" PA / instrument drivers with relatively low (95-96dB) sensitivity are sometimes candidates.
Punch the specs into an efficiency calculator, (see the link)
Punch the specs into a sealed box calculator (same site)
E.g. P-Audio P-18N "designed with a vintage voicing" (I look to P-Audio first mainly due to local availability)
3.03% efficient (96.8dB / watt)
-3dB at 72.62Hz in a ~120 litre box
It works in a reasonable box, but with a relatively high Fs. Depending on your room and tastes, that may be low enough.
Eminence DELTA-15LFA, which is only $100 in the USA:
2.62 efficient (96.2dB / watt)
-3dB at 57.45 in a ~210 litre box
If something like this looks like a reasonable compromise to you, go for it! They are easy systems to get right, and forgiving - it doesn't matter so much if the drivers don't exactly match advertised specs, or if you make the box 10 litres too large or small.
I have an all sealed system (using 6*15" drivers) and rather like it.
Follow Ups:
I wouldn't call them high efficiency (87db - 92db) but you can get reasonable efficiency in a sealed box and a decent f-3, with some of the 15" woofers at Parts Express (if their specs are to be believed). If you have room for multiple drivers in a giant pox, you can have it all!
Dave
The quick check is to calculate fs/QT. You can get 0.707 of that for a Butterworth alignment, or 0.577 for Bessel alignment. But you can't really get below about 1.4 times the free air resonance fs without impractically large boxes. In the fifties people would mount speakers in heavy closet doors, using the coats and hats as damping material. Some even used fireplaces for the ultimate transmission line design!
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: