I made a pair of Bruce V1.2 from the Frugal-horn site (Spawn family). Started it a long time ago but it got shelved when life came in the way. Can't say I'm happy. Very thin sound, bit like a tiny transistor radio in a cavern.
Is there a reasonably simple enclosure for those Fostex speakers so I can at least salvage them into a usable speaker? The enclosure Fostex proposes is a bit a puzzle of all little pieces and I'd like something with less sawing involved. Something like a simple BR?
Is there a reasonably simple enclosure for those Fostex speakers so I can at least salvage them into a usable speaker? The enclosure Fostex proposes is a bit a puzzle of all little pieces and I'd like something with less sawing involved. Something like a simple BR?
I'm not surprised. Bruce was designed for the FE207E, which had rather different specs. to the FE208ESigma, and for it to work in that enclosure, the latter really needs some series R (or an equivalent high / adjustable output impedance amplifier). The overdamped (low Qt) characteristic is why it's not well-suited as-is to regular vented box loading.
You don't mention what your amplifier is, but if it's a regular voltage source type amp, then with a 2.5ohm power resistor inserted in series, about 13 litres tuned to 67Hz would be OK[ish] near boundaries. If you want more, then assuming about 6.8ohms series R, 44 litres to 44Hz would do, in similar conditions. 8.2ohms series R would allow a Vb = Vas, Fb = Fs alignment, near enough.
You don't mention what your amplifier is, but if it's a regular voltage source type amp, then with a 2.5ohm power resistor inserted in series, about 13 litres tuned to 67Hz would be OK[ish] near boundaries. If you want more, then assuming about 6.8ohms series R, 44 litres to 44Hz would do, in similar conditions. 8.2ohms series R would allow a Vb = Vas, Fb = Fs alignment, near enough.
Havoc,
It is worth mentioning that the same resistor trick Scott specifies for a simple reflex should also work with Bruce. I would try that first before venturing towards a new box.
dave
It is worth mentioning that the same resistor trick Scott specifies for a simple reflex should also work with Bruce. I would try that first before venturing towards a new box.
dave