I have a pair of EVM 15B's in a TL-606 CAB.
My main thoughts about them is this.
They're good for a particular type of sound.
They are a little on the dark side, as far as the 15B's fall off a cliff past 3kHz
In certain rooms you can get a good deal of room gain from them in the bottom part of the spectrum.
But I find they can be quite anemic for 5 string bass, as there is absolutely no fundamental support, and the 2nd harmonic is greatly lacking often, for an open B or A.
The biggest problem I've had with the EVM 15B is if you over power the thing at certain frequencies, the driver has a limited XMAX, and it makes a god awful popping noise that sounds like a circuit arcing, when the coil hits the keeper plate.
Otherwise good for a certain sound, but the 15B is a bit outdated. I haven't tried investigating other drivers for the TL-606.
I also have a bunch of the TL-806?? For the EVM 12L's They actually deal with being pushed a little better, but have a little less bass extension.
Antone-