Non-co-planar Dual Drivers

[svorkoetter]

I wasn't sure whether to post this in Loudspeakers or Full Range, because I'm using Full Range drivers (Pioneer), but the question is really a more general one. Here goes:

I'm building some extension speakers (with their own amp) for a Hammond organ. So right off the top, this is not hi-fi (the Hammond's tone generator only goes up to 6kHz). Due to space constraints, I want to install the two drivers in each cabinet at right angles to each other, and some distance behind the front grill. Here's a top view cross-section done as ASCII art:


BACK
+--------+
| . . . .|
| . /\. .|
| ./. \ .|
| / . .\ |
|/. . . \|
+--------+
GRILL


Ignore the dots since they're just there so the forum software doesn't collapse the spaces.

The drivers, which are wired in series, would be installed on the slanted faces, which are at right angles to one another, and at 45 degrees to the front grill. Does anyone have any opinions (or facts even) regarding this arrangement? Will the two drivers be "fighting" one another, or will they work together to project the sound out the front?

Remember, I don't need hi-fi sound here, but I don't exactly want no-fi.

Thanks

[Geoff H]

The output of the two drivers should combine, and project the sound forward with the advantage of some horn loading. Placing the drivers close to the apex should reduce cavity effects.

I've considered a similar scheme for bass reinforcement on OBs, but haven't actually tried it.

[svorkoetter]

Thanks. That's what I was hoping to hear. If it boosts the bass, all the better.

I've done electronics for a long time, but I'm a bit new at this audio stuff, so please forgive the dumb question, but what are "OBs"?

[Moondog55]

"OB" Open Baffle; that is either a flat baffle board or one of the implementations with no box, called variously H W V U M baffles from the shape.
W baffles are usually used in the vertical to save floor space, it can be viewed as way of using very high "Q" drivers or as design goal in itself, power handling is poor but drives work all the way down to resonance.
Wasn't a dumb question at all, I just hope it's not a dumb answer

[svorkoetter]

I'm back, and the project is completed. In case anyone is interested, I've written it all up on my web site at:

stefanv.com/electronics/hammond_window_seat.html



I'm really happy with the way it turned out, and it sounds great! Thanks for the advice everyone.

[badman]

Originally Posted by svorkoetter

I'm back, and the project is completed. In case anyone is interested, I've written it all up on my web site at:

stefanv.com/electronics/hammond_window_seat.html



I'm really happy with the way it turned out, and it sounds great! Thanks for the advice everyone.

Nice project, I'm not surprised at all that it worked out well. One thing: given the 6kHz bandwidth requirement and the splayed construction, I think that tweeter is fairly extraneous.

[svorkoetter]

Originally Posted by badman

One thing: given the 6kHz bandwidth requirement and the splayed construction, I think that tweeter is fairly extraneous.

True, for the organ, but my retrofitted drum-machine (which bypasses the Hammond's amplifier entirely now) benefits from the extra bandwidth. The cymbals and snares sound more muted without the tweeter.

[Steerpike]

Your design is little like a extreme case of what Revox did with 4 bass drivers on the BX4100 - the four-section baffle shaped like a backwards-pointing pyramid.