Originally Posted by Steve Eddy
How is that?
This will be getting mighty off topic for this thread, but Ok. My equipment is in no way typical for the full range pursuit. The Hammer Dynamics Super 12 is not much like any other full range speaker. It was designed from the start to have a tweeter and no sub. It does not sound much like the other extended range twelve inch speakers - Zu Druids, AEs, the vintage brands. Nor does it remind one of Tannoy concentrics. They all do things I don't personally find pleasing. It is more like a Fostex, which I like a lot, only much larger.
While I have systems up to eighteen inches, I know twelve inch speakers are plenty for a home. So I was intrigued when a friend in Australia told me how great the Hammers sound. I did some research into construction methods for speaker cabinets, because I felt a more rigid enclosure not based on bracing would sound better than the suggested box. I had seen an unusual router based scheme from a man in Scotland and applied it. It worked very well.
Then I tried all the incarnations of the various crossover elements. That was tempting because this speaker has very little of the difficulties full range speakers are known for. It doesn't shout and does not need a complicated enclosure to produce good bass below 50Hz. Its natural rolloff on top blends well with the tweeter's characteristics. Trying it without them, I found the low pass filter in the network was unnecessary, as was the second order high pass. I put a 2mf cap in series with the Audex tweeters as a first order high pass and I found the blending to be natural sounding to me.
The notch filter was dealing with relatively minor anomalies as compared to other better known full rangers. As I said, this is no Lowther. When I read Nelson Pass's articles about tranconductance amplification I suspected that the accurate voice coil movement resulting from the application of the technology would go a long way to iron out the FR of the Super 12. It did. Being now very happy with the way it now sounded without the notch filter, I kept it out of the system. The full range and tweeter leads are together in the output posts of the amp; this couldn't be simpler. The transconductance amp makes the bass realistic and outstanding to below 40Hz. The amp will enhance bass response in any full range driver (my friend's eight inch Fostex Omega cabinets don't need a sub either; it has to be heard to be believed), but it took the Hammers all the way to fully realistic. It smooths out the frequency anomalies to where I don't notice or hear them. Without the networks the 97dB speaker is now a 105 or 106dB speaker. All is good with the world. Everyone loves the system. My friend with the Omegas says, in response to how he likes other speakers, "I don't like crossovers anymore." Sometimes, if you do your homework, slicing the midrange into two or three pieces really isn't the best idea out there.Edited by Clarkmc2 - 9/20/12 at 1:14am