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-   -   Small driver, big cabinet, killer bass and efficiency (http://www.diyaudio.com/forums/multi-way/228516-small-driver-big-cabinet-killer-bass-efficiency.html)

sreten 24th January 2013 02:32 AM

Small driver, big cabinet, killer bass and efficiency
 
Hi,

I've been perusing the content of :

http://www.quarter-wave.com/Horns/BL...gn_Article.pdf

And it seems to me this is a way of doing several things with a small driver :

1) Avoiding BSC, that gives a big jump in efficiency.

2) Excursion control at low frequencies, basically a lot more bass given Vd.

3) Actually requiring placement in corners, not good with some designs.

Designed of course for FR drivers, but that doesn't stop you using
it with a decent efficiency, decent throw but not too low Fs driver.

An inverted driver arrangement is probably easiest.

Strikes me this should work well :
Zaph|Audio - ZA14W08 Woofer

Possibly the ZA5.2iw croosover from
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter

Very big of course for the driver size, but some people like that.

And not perfect either, but a different ball game to a 10L box.

rgds, sreten.

tvrgeek 24th January 2013 11:34 AM

Retracing the K-Horn at a small scale? Ironic, I was just commenting over there to the gentleman who wants a 15 inch midrange, Paul's main thesis was that distortion and efficiency are inversely proportional.

I am doing my third set of speakers with the Zaph drivers. Traditional ported this time. I was totally unhappy with them the first two times around. They hit an odd gap in the market which I am sure is why John had them built. He is not kidding when he warns you to notch or keep away from the breakup range. Below that, they are very clean for the money. I have two ideas this time around. Very low very steep crossover to an SB tweeter that goes about as low as any small tweet can, or a three way using a 3 inch mid and spreading the crossovers even further but low order. Maybe even first. (Is this Vanderstein's secret?) Building both ideas to compare. Wonder how that would work as a corner horn? Folded corner horn on the Zaph, big waveguides on the mid and tweet.

Another driver you may think about is the Planet 10 modified Fostex. I found they still need a tweeter, but they are as close to ultra wide range as I have seen. Mark Audio maybe? Zaph is a lot cheaper.

Post your progress. Sounds like a fun project.

mondogenerator 24th January 2013 02:09 PM

Sreten: may I ask why a low Fs driver would be an issue?

Im not all that au fait with BLH designs, and I ask since I have a quad of 5" drivers with Fs at 60-70 hz, my mains having Fs of 40hz. The former have got me thinking of interesting designs to get the best from them.

Michael Chua 24th January 2013 04:00 PM

Quote:

Originally Posted by tvrgeek (Post 3339992)
I am doing my third set of speakers with the Zaph drivers. Traditional ported this time. I was totally unhappy with them the first two times around.

The ZA14 is a good driver. The mids are exceptionally "clean", perhaps due to low harmonic distortion.

In a BR, with EQ (passive or active), you can get some nice bass out of it. Doesn't go down to 40Hz, about 50~60Hz (-3dB) but bass is tight and defined.

I have no issues with the cone breakup. 2nd or 3rd order at 2K2~2.5K is enough to bury it.

Regards
Mike

sreten 24th January 2013 04:48 PM

Quote:

Originally Posted by mondogenerator (Post 3340139)
Sreten: may I ask why a low Fs driver would be an issue?

Hi,

By implication a low Fs would imply 5" drivers with parameters
too far off the family of drivers the BLH is designed for and I
wouldn't like to guess how well it would work or not.

Generally low Fs is low efficiency for a 5", and high Vas and Mms.

The Fostex is 89dB, 67Hz, Q-0.42, Vas-7.3L.

The ZA14W08 is 87dB, 66Hz, Q-0.44, Vas-5.2L.

Quite similar, the differences in Vas echo a 5g cone mass vs 7g.

I cannot check it with the worksheets, someone could.

rgds, sreten.

"All of the crossovers use a tiny cap across the first woofer
inductor as a trap circuit to kill the breakup a bit more "

mondogenerator 24th January 2013 05:46 PM

ah ha. Thats exactly what i did with my mains, 47uH in series with 5uF using visaton AL130. Worked a treat. Thanks for the reply, perhaps my old Audax AP130ZO with their aged Fs could work ok. Again thx.


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