How? 2 stereo tweeters but only one woofer

[Pdwhitt]

I am building a small boombox, using a stereo amp, with (2) 3" tweeters, but I only have room for one woofer. I want to maintain the stereo output of the two tweeters. My amp only has two stereo outs, no mono out. How do I wire the single woofer?

 

[Michael Bean]

No easy way to do that. It would make more sense to forget tweeters and woofers, and just go with a couple of small full range drivers instead.

Mike

 

[Drew Eckhardt]

Use a dual voice coil woofer or sum the amplifier outputs with a transformer.

 

[dangus]

Use 4 ohm stable amps and wire the woofer bridged. This requires inverting the phase of one channel, and reversing the polarity of one mid/tweeter. Also, that the amps are not already bridged (as most digital amps and "high power" linear amps that run from 12V are).

 

[magnus h]

I am building a small boombox, using a stereo amp, with (2) 3" tweeters, but I only have room for one woofer. I want to maintain the stereo output of the two tweeters. My amp only has two stereo outs, no mono out. How do I wire the single woofer?

Did you solve the problem? I am interested in a solution too.

I found this, which might be helpful
Why Not Wye?

 

[lcsaszar]

I think a two-input crossover (two separate L, one C parallel to the woofer) might work.

 

[midrange]

There is a very easy and satisfactory way to do this. Buy a Monacor sph 135 tc. The tc stands for "twin coil". It has 2 coils driving the same cone. They are electrically separate. So you just connect one channel to one coil and one channel to the other.

It is very similar to the 135 ad, with a higher Q and a lower Vas, with a very slightly flatter frequency response. If you only want it for mono, the 2 coils can be joined in series for 16 ohm or parallel for 4 ohm.

 

[kbzx35]

Dual Voice Coil would be your sure and simplest bet. I built a small boombox off of an Audience A3 DVC 3" and a chipamp with success.

 

[BlueWizard]

There are also transformers, typically found in IN-Ceiling speakers that take Stereo inputs and blend them down to a single mono output. Find a place that specializes in In-Ceiling and In-Wall speakers and they should have these stand alone transformers.

Typically this would be used in a in-ceiling in a bathroom where there is limited room available. One speaker carries both channels. In some case I have seen In-Ceiling with two stereo tweeters but a single mono woofer. This increases the sense of stereo imaging.

Just to illustrate the point -

RMD: Rack products and electronic accessories for home and small business?

In reasonably affordable Dual Voice Coil woofer, consider Dayton Audio -

Dayton Audio SD215A-88 8" DVC Subwoofer 295-484

Dayton Audio SD270A-88 10" DVC Subwoofer 295-486

Keep in mind, each voice coll is 4 ohms.

Steve/bluewizard

 

[magnus h]

Thanks for the replies!
The "72 Watt Stereo-to-Mono Isolator Transformer Mixer Panel" might work but i still need a crossover to keep the high frequencies in stereo for the tweeters i guess.

I didn't know about Dual Voice Coilwoofers until now. Seems like the cheapest solution.
But they seems rare. I am looking for a light weight (Neodymium) high efficiency duel/twin voice coil woofer in 6-8" for my project.

Any ideas if such a woofer exists?

 

[Pdwhitt]

Did you solve the problem? I am interested in a solution too.

I found this, which might be helpful
Why Not Wye?

The "wye" looks like an interesting option.

 

[magnus h]

The "wye" looks like an interesting option.

The conclusion of the article is that wye is not an option

If you can find a dual voice coil woofer it seams like an easy solution. Haven't tried it myself however.