Whats Your Favourite Passive OB Bass Driver

Hi,

The Altec is probably a nice driver for a box but a dreadful choice for
a passive open baffle speaker due to its very low Qts of 0.23, and
TBH the Xmax is not that impressive either for the application.

Checkout MJK's articles on passive open baffle speakers :
Quarter Wavelength Loudspeaker Design

rgds, sreten.

The Eminence Alpha 15" is very popular.
 
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Hi,

The Altec is probably a nice driver for a box but a dreadful choice for
a passive open baffle speaker due to its very low Qts of 0.23, and
TBH the Xmax is not that impressive either for the application.

Checkout MJK's articles on passive open baffle speakers :
Quarter Wavelength Loudspeaker Design

rgds, sreten.

The Eminence Alpha 15" is very popular.

Do not only look at the Q also Fs,Vas. The altec is very very good here simulation 2phi.
192322d1287182910-ob-project-design-started-help-requested-altec.jpg
 
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skorpion

Member
2004-10-26 7:12 pm
Helmuth, all your Hornresp simulations how are they done ?

Hornresp is not very suited to do OB simulations since the programme suppose a centric placement on the baffle. You can do simus of the naked driver which is interesting. But to get things right with OB simulations you have to take the combined SPL response to account for the bass loss.

/Erling
 
Helmuth, all your Hornresp simulations how are they done ?

Hornresp is not very suited to do OB simulations since the programme suppose a centric placement on the baffle. You can do simus of the naked driver which is interesting. But to get things right with OB simulations you have to take the combined SPL response to account for the bass loss.

/Erling
Yes your right Erling, my simulations did not calculate combined response.

It doesn't really chance the indication about the woofer being suitable for OB.

The combined response depends on how far away the woofer is placed from the backwall. So it also not possible to give the exact response.

combined for sph250ke
 

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Simulation of Eminence Alpha15 by itself (No Baffle) 2Pi 1 watt would look like this:

[IMGDEAD]http://img813.imageshack.us/img813/1482/nobafflealpha15.jpg[/IMGDEAD]

/Erling

witch distance for combined did you use Erling. Ok I can see 19cm sorry.


Do you really think this is a better simulation. Here is no floor or baffle that did help the low frequency it is ok for nude chassis placed near floor or wall.
 
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Pano

Administrator
Paid Member
2004-10-07 6:05 am
Panama
Do not only look at the Q also Fs,Vas. The altec is very very good here simulation 2phi.

It's a great driver, but not for OB. Unless you use 4 per side. ;) No matter what the plots say, it not really practical. I know, I own a few.

I am afraid that the mid of the goldwood could be to poor qaulity.

It's much better than you think. Used in a 3 way system, it's actually rather clean. Somewhere here I have measurements taken at LSAF. It does need a little trap circa 3Khz for best performance. It also has a nice bump at 16Hz for those organ pedal tones.

The Peerless is super clean. But it's a 12 and you'll need to throw a lot of power at it. It can take the power, but it will always be low efficiency on OB.
 
The behaivour of the eminence alpha is quit rare.

It is easy to copy that behaivour by using two high Q drivers in series. And best types are high spl 4 Ohm car sub woofers/ or pa.

I simulate here a monacor car sub in series. So it stretches the low end with the bump at Fs in combined response.

Ad 3 dB to the spl. It is low efficient because they are in series it makes in passive low end configuration easier.

MONACOR INTERNATIONAL:product detail page
 

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