Greenie512

Aperiodic: CSS FR125SR

Here’s a little full range speaker designed by Planet10 for the CSS FR125SR driver.

See design

The idea behind (literally) the aperiodic design is the sloping back. The above picture is bits of scrap cut to achieve the 60 slope. Cuts went well, so time to try it for real ...

Above is a “dry” fix to finalise panel positions.

Second box glued and clamped.

Conclusion

At first I was rather underwhelmed but remembered that the CSS’s are not as efficient as most FR drivers. With the Fostex drivers I turn my volume control down with the CSS I need to turn it back to normal levels and - zap we are away.

For such a tiny box these are great FR’s much more body and perhaps more “normal” speaker sound than the Fostex drivers. When I say normal I mean what most people would expect a multi driver paper cone speaker to sound like. I still like the Fostex sound but must admit the CSS is a dam good driver.

Most full range speaker need big boxes to get the best out of them and you can do this with the FR125’s but in this little aperiodic design the perform really well.

Having said they are not very efficient, I’ve just moved them into my “shed” location (lack of space) and they are hooked up to a T-amp which is driving them reasonably well but have a sneaky feeling 20 watts plus might be a better power level.

Finally got around to covering these little guys with a bit of scrap veneer - Jarrah and Sliced Pacific Maple sides