easy high-efficiency?

[gongli]

hi a relative gave me a diy amp which needs 2 high-efficiency speakers. (my track record on diy amounts to installing a curcio capacitor board into an st70 a few years ago, leading to a puff of white smoke and then ... aanyway...)

im on a tight budget but id like to have some speakers for the amp to use. i dont need loudness, and i do need them to be small. so i have 2 questions:

a) what are the cheapest i can buy ready-to-use on ebay?
b) how would i go about making a simple, cheap, but good sounding speaker?

thanks

[sharpi31]

high efficiency + small size = no bass

So if you want high efficiency with some bass, the box will need to be a good size. This is a good simple high efficiency diy project:

The Big Fun Box - single driver speaker [English]

[tinitus]

Originally Posted by gongli

im on a tight budget

And how tight is a tight budget ?

[Glowbug]

The BIB design is about as simple as it gets, but it's not exactly "small"

[ksporry]

Hmm, am I wrong or is 45liter quite small?

[multisync]

30cm X 30cm x 30cm =27000cu centimeters or 27 liters, 30 cm is about 12 inches.

25cm x 30cm x 60cm = 45000cucm or 45 liters

[lousymusician]

Originally Posted by gongli

hi a relative gave me a diy amp which needs 2 high-efficiency speakers. (my track record on diy amounts to installing a curcio capacitor board into an st70 a few years ago, leading to a puff of white smoke and then ... aanyway...)

im on a tight budget but id like to have some speakers for the amp to use. i dont need loudness, and i do need them to be small. so i have 2 questions:

a) what are the cheapest i can buy ready-to-use on ebay?
b) how would i go about making a simple, cheap, but good sounding speaker?

thanks

Do you have room to add a subwoofer or two to the mix? If so, take a look at this for one solution:

great speakers for S.E.X.

Fostex FE166e drivers in very small boxes, with a sub or two for support. They crossed at 125 Hz with two subs, I found I could get away with 100 Hz and one sub without too much penalty. The Fostex will make the most of the low powered amp!

[Godzilla]

http://www.parts-express.com/pdf/264-847s.pdf

Not as efficient as the Fostex mentioned above but can be put into an even smaller box and used to good effect with powered subwoofers too.

http://www.parts-express.com/pdf/264-854s.pdf

These woofers are on sale and can work nicely in small ported cabinets but need a powerful amp to drive them.

Just a thought.

[pjanda1]

If you need high efficiency, you need 6.5 or 8 inch fullranger. For any given driver, a sealed box is the smallest possible enclosure, but some drivers won't give you enough bass without a more complicated box.

The S.E.X.y speaker is a very good approach. As Paul Joppa outlines, the sealed approach considerably reduces doppler distortion when compared to fullrange drivers in vented boxes (and reduces the size of the mains too). If you can tolerate a slightly larger enclosures (22-36L, say), then you can emulate it with 8" drivers (like the B20 requires a tweeter, or the BetsyK speakers I sell) (do note that the B20 requires a tweeter) and gain even more benefit. A larger driver will be even more efficient and reduce distortion further. In addition, the right driver will go lower. it might be possible to get by without a sub, especially in a small room with considerable gain. If you do need a sub, you only need one, and placement is much easier. In addition, you are free to use more interesting subs that aren't useable to higher frequencies (tapped horns, EBS alignments). I lived happily with 8"ers in sealed boxes -w- a sub for quite awhile. I'm surprised it isn't a more popular approach.

If you need something simpler than a sealed box, you could consider some sort of open backed box. I've looked at some rectangular wall mounted shelves, and thought would could glue a baffle over the front, shove the back full of fill and see what happens. This approach would require a higher Qts, like the Visaton B200, my Betsy, or if you can tolerate a hump in the midbass, the $9 fullrange that is currently on sale at Parts Express. Aperiodic boxes are an option too, and more tolerant to build than a sealed box.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers