Troels Gravesen high efficiency 3-way looks like a winner.
Troels Gravesen recently published a speaker design on his website that looks like it could be perfect for those with low-wattage tube and Class A transistor amplifiers. The speaker is a 3-way unit built with a ScanSpeak tweeter and Faital pro PA woofer and midrange. The crossover is a simple LR2 design at 500Hz and 2400Hz, and the cabinet is a bass reflex box of Baltic Birch which appears to be fairly easy to build.
Mr. Gravesen claims a sensitivity of 93dB/2.8V/1 meter. His measurements show a very flat frequency response which appears to be plus or minus 2dB from 100Hz to about 15KHz, and off axis it deviates from that only slightly at 30 degrees. Based on the raw driver specifications and the box size of the speaker, it appears that bass extension should be about F3=48Hz and F6=42Hz, enough bass for most varieties of music. Mr. Gravesen rates it as an 8 ohm speaker, and the impedance never goes below 5 ohms at any point, so it should be an easy load for most amplifiers.
I am no expert, but I believe this to be a remarkable design and I think it shows Mr. Gravesen's expertise clearly. If I were in the market for a DIY speaker this is the one I would build. I think it is perfect not only for the low-wattage folks but also for speaker building Newbies that want to get their feet wet. It can be found at www.troelsgravesen.dk/Faital-3WC.htm
Last edited by Beatlejuiced; Today at 05:24 PM.