Close to the Edge

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Thanks to that amazing piece of software 'The Edge' I've made a simple Q&D OB. The Edge had the driver placed closed to one edge of the baffle, & although I was sceptical about this I tried it, and it worked amazingly well.
Now I want to know why I can't make the baffle like this?:


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Immediately noticed an 'enclosed' feeling to the sound, not as good as the flat baffle (need to do more listening). Ameliorated a little by turning the corner to the front. Tried swapping L & R sides - immediately noticed an improvement in low end; so my time wasn't wasted. So for asymmetrical baffles, the long side should be on the inside?


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Hi Dave,

Its a 165x65 cm unit out of an old Sony tape recorder,
sorry don't have the part # handy, but it sounds good & has a reasonably wide range; I'm planning to add piezo tweeters & 12" woofers when I sort out a good baffle shape (which will probably be an asymmetric pentagon); I'll Damar it as well.

Pete McK
err..make that mm

sorry, much smaller.

Actually, I do have a pair of larger oval units of about the same vintage, Magnavox, a defunct Aussie brand I think. These are about 10" x 4", but don't have very good lows & squawky highs due to their whizzer. I've Damared the cones, and I'm going to try some car underseal on the accordion surround to see what change that makes (+ damp the whizzer or remove it).
...the result...

added a piezo for some sparkle, & xo'ed (6dB/oct) at ~130Hz to a Hi-Q (Qts = 1.46) woofer, using the loudness switch on my amp for EQ.
Only prob is that the Sony (#125-11) can only handle 4W, so breaks up a bit if I push the low mids, might try a higher Xover
Initial impressions - very natural balance on jazz, I like it. Gonna try something similar with my Peerless drivers.


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Hi Dave,
I'm using 115uF, might cut it back to 68.
On further listening, I'm still very happy with the balance, although the Kick drum doesn't hit you in the 'nads, the speaker has a very even sound, particularly for Bass, all the way down. Fs of the woofer is 33Hz. I'm amazed by the naturalness of the piezo too.
Pete McK
Re: yep,

PeteMcK said:
I'm amazed by the naturalness of the piezo too.

I've always been amazed by the piezo tweeter too. But in a slightly different light mind you. My amazement has to do with their modus operandi not the sound quality. Can't say I've ever thought of a piezo as "natural" sounding. Industrial? yes, natural, no. How is it crossed over?

Cal someone here recommended..

Hi Cal,
I don't know who posted this method,
but I used .68uF, followed by 22 ohms in parallel then 33ohms in series with the driver. (values aren't strictly as recommeded, I used what I had). This gives no obvious transition, but there's plenty of hi end energy. Cymbals & snare drums sound real...
and no harshness that I would have expected. Perhaps because the Xover freq is fairly high. Anyone know what the xover frequency is using this method?
Pete McK
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