The 215-EC uses quite a lot of current - 5A at 12V. This requires a hefty power supply, and if regulation is used, then quite a large heatsink.
Another method is to use one of, or a pair of deep cycle 12V batteries.
With a trickle charger to keep the battery/s topped up, this a quite an effective solution and sounds very good.
However it takes up quite a lot of room space, is a bit ugly, and inconvenient.
I built 3 prototype power supplies , and chose to go with regulation using LT-1083 regulator chips , which are rated for 7.5A, 300VA 2x12V transformers and quite a substantial bank of capacitors for a stiff power supply. More heat-sinking than necessary so as to run cool and reliable.
The first PSU (power supply unit) used a pair of high current chokes to provide a very clean supply to the regulators. This is way over-kill and the next unit did away with the chokes, and no difference in sound quality was noted.
The next unit used a constant current regulator circuit, which provides constant current rather than constant voltage to the field coil.
In theory, this should be the least effective method, but over the long term, I quite liked the sound from the CCS.
The difference is very subtle, but it just sounds a bit smoother and easier to listen to.
I also settled on 10V operation , it seems to be a nice compromise between the more laid back 8V and the dynamic , but forceful 14 V operation.
Of course voltage selection will depend on the system the driver is used in. Open baffle is quite different to box operation and a quite different operating voltage could be required.
The Q's or parameters of the 215-EC are changed with different voltages so in reality they are quite different drivers at different voltages.
The drivers are mounted on a flat piece of plywood with solid pine bracing . I placed the 215 between two Eminence Alpha 15" bass drivers, which are designed for open baffle use. 215 is at ear level.
There is no crossover on 215, it is connected to a SE-300B power amp , which is driven by one of my DHT preamps.
The woofers are connected to tube monoblock amps, which are connected to DEQX unit, which is connected to same preamp.
Crossover in DEQX is 250Hz @ 24dB. this might seem a bit high, but in open baffle the 215 rolls off quite high and the Eminence has to be brought up to flatten the curve, as much as possible.
I also have some bass EQ to counter the eminence bass roll-off and give it a bit of oomph.
So how does it sound in this first, basic version?
Ive never been a fan of "box" speakers, the typical 2 or 3 way just doesn't provide enough excitement or realism for me. No matter how expensive or exotic, they always sound like a pair of speakers.
Planar speakers can also have their limitations, however the best do possess an ability to give a big wide sound that does come close to what you would actually hear in a studio or live entertainment venue.
Likewise with horns, the very best have a palpability that is to die for.
I'm not so much into impressive sound with explosive bass and scorching treble, I'd rather listen to something that has a natural musical tone and dynamics that simply sound real.
Music touches me when it gets close to revealing the emotion , ability and performance of the recording.
I don't want to listen to speakers, I want to listen to the recording.
The Supravox can do that, they do a very good job of disappearing and leaving the music in place.
Imaging, sound-staging are near perfect.
I haven't heard a speaker that can throw a big a sound as my modified Accoustat 2+2's , but at 8 foot tall and requiring 4 channels of 1000W , they are bordering on impractical for most situations.
The Supravox come very close and only require low power, preferably a tube power amplifier.
Like all full range drivers they are not monitor studio accurate, but they don't shout or have excessive peaks like Lowthers and the other full range drivers.
They are not perfect, but they are very interesting, and very satisfying drivers. You don't tire of the Supravox sound. Indeed its hard to turn them off!
Like a good tube preamp, they don't scream out their advantages, but take them away, and you soon miss them very much.
The integration with the Eminence bass drivers is good. Open baffle bass is a very interesting subject , and subjectively, very easy to listen too.
Open baffle cant do very low sub-bass, but what it can do is very articulate and defined bass. There is no boom or overhang . It may sound "light' if you are used to big subwoofers moving lots of air, but the definition is quite startling once you come to appreciate it.
If you have ever sat next to an acoustic bass you will have noticed there is no boom or lack of definition , you can clearly hear every note - open baffle bass is like that, the bass lines are very easy to follow and enjoy.
All in all a magnificent speaker system, but in Pt 3 I measure them, use digital speaker/room correction to make them damn near perfect, and use them with the amazing RAAL ribbon tweeter.
