Horizontal (but closely spaced) speaker configuration

[budnick11]

Hi all, thanks for creating this forum. I've learned a lot so far just browsing old threads.

My project idea is for a portable, battery-powered iPod "boom-box" enclosure. I've had 1 too many crappy store-bought iPod speakers, and would like to build a custom system that sounds great.

I have a 4" woofer and a 1" tweeter picked out, and plan on constructing the cabinet, crossover, and power system myself. In order to make this more portable, I want to place the 2 drivers side-by-side. A vertical driver configuration is possible, but it would probably make the box a bit cumbersome and unwieldy.

If I place my 2 drivers directly side-by-side, how bad might the lobing effect be, given that they will be very close together? has anyone attempted this before? Should I just go with a single high quality full-range driver instead?

If anyone's interested, here are the drivers I've picked out:
Dayton Audio DS115-8 4" Designer Series Woofer 295-424
Dayton Audio DC28FT-8 1-1/8" Silk Dome Truncated Tweeter 275-076

And here's the amp:
Dayton Audio DTA-2 Class T Digital Audio Amplifier Module 300-385

I'm open to suggestions, and any additional advice would be welcomed. I design and build switching power supplies by trade, so I've got the battery and power regulation side of things 100% figured out. But I'm a bit new to this speaker building thing.

[budnick11]

[DougL]

The answer to any engineering question is "it depends"
in this case, it depends on your crossover frequency and slope.
Since your drivers have several octaves overlap, you should be in good shape.

HTH

Doug

[DeonC]

Hi

May I make a suggestion here? Build your front baffle with a slight v-shape, so that the drivers face away from each other. That way you'd get a bit more stereo seperation. I would say about 120-degrees between the two baffles.

BTW, have you had a look at the available 3'' drivers? Units like the Fountek, TangBand and Audio Nirvana drivers might allow for a smaller box, but still sound good enough for the iPod. Just a thought.

Enjoy,
Deon

[picowallspeaker]

Good deal !! I would have said same as Deon
Didn't think of the fullrange application , though
More over , I would make all the (3) pieces detachable ...
I don't know if wiring affects stability of class D amps
So the boxes with triangular shape -and strange form because they have to accommodate the central box - would be attached to the body
(amp+batteries, central box ) to their basis , and could be occasionally be positioned alone , being naturally toed-in at 45°

[picowallspeaker]

And the speaker choice is good , although it needs a working crossover .
If played to their full potential , ( I Think ) those speakers are going to beat every
portable box ever seen ! But ...the volume needed for the box may be too big ,
and also the weight . Still I propose to make them separate and possibly attached
to the central body in an elastic way !

[wintermute]

It's a good question regarding the horizontal placement of the tweeters beside the woofers.

If I had to hazard a guess I would say put the tweeters on the outside of the woofers rather than on the inside. If they are close together you are probably not going to notice any difference to a vertical placement provided you are at a reasonable distance (so that the difference in path length becomes negligible)

The reason I suggested tweeters on the outside is so you get less interation from channel to channel, but I'm uncertain whether shorter or longer path length for tweeter would be better.

I guess you could always try with a removable baffle to start with and make two and try both ways

Tony.

[DeonC]

Been thinking about this. If you go the route of the small fullrangers, then you could make the central box an amp-and-sub box. Get a nice 4'' to 5'' sub and a second digital amp, parallel the outputs of the amp, and build it all into a larger central box. A small sub-sat system then. You can then place the sats wide for decent imaging, with the central unit providing power and bass.

Enjoy
Deon

[Keriwena]

Over the years, millions of "bookshelf" speakers have been laid on their sides (to fit on bookshelves, of course!) and greatly enjoyed by their owners. Even the venerable JBL100s were often used horizontally. Since this is a 'portable' project, and thus room placement may be arbitrary, I humbly suggest in most situations, lobing will be low on the list of acoustic "problems".

[budnick11]

Thanks for the replies, this certainly gives me a lot to think about.

I like the idea of increasing the angle between the speakers bit, even if it might complicate the cabinet design.

It's also a good idea to make each speaker removable. Then I could flip them on their side when needed and not even worry about the vertical/horizontal placement issue. The only challenge I might run into with this is that I want this setup to be somewhat rugged for outdoors use, and I'm not sure my woodworking skills are up to something like that!

Deon, can you recommend any fullrange speakers which would be good to use as satellites? A lot of the fullrange speakers seem to be tilted more towards the low end at the expense of giving a nice tweeter-like response.

Keriwena, I have to say that you might be right, and I may just be splitting hairs here worrying about this. The best idea seems to be just buy the speakers I want and make a test setup to see if I can even notice a difference with all of these different configurations, as wintermute suggested.