brombo wrote:
What about horn loading the scan speak driver. I think about the old Altec Voice of the Theater configuration except that the driver would be in a sealed box and not ported since the subwoofer would supply the low bass.
But that is an efficient 15" driver that is designed to work in horns. Usually Qt is around 0.2 or so. THis driver has a Qt of 0.38. There are other parameters of interest that determine the acceptability of horn loading, but need to model this in Horn Response to get an idea of performance. The front horn will not benefit all frequencies, my recollection is that it really helps in the midrange, but is too short for boosting bass response, which is dominated by the vented box loading at the back of the driver. The best you can really hope for is 10dB.
The driver is actually around 87 db 1W/1m. The Radian driver is 112 dB 1W/1m. Not sure if this included horn gain. This is a 25 db difference. The bass driver will need 316 times the power as the 2" Radian driver to deliver the same output power. This is not a good place to be. The RMS rating of the driver is 100W, peak at 200W. Not clear what the actual limit is thermally. The maximum this driver can deliver "theoretical" is +20dB over the rated sensitivity, not counting excursion or thermal limits. But you will be pushing alot of power through the driver, which will warm the voice coil and impact driver linearity, whereas the midrange will be running at fractions of a watt with little temperature rise and will have good linearity.
If you are talking a passive crossover, then you will be padding down the midrange and tweeter. Alot. This dissipates alot of power needlessly. You will need an active crossover and separate amplification.
This is not saying it cannot be made to work, it is just the 8" driver is constraining the potential of a nice horn system. You really need to look for a better suited driver rather than trying to make this one work.
David