Rerurn to Romy the Cat's Site

be wrote:

"another big selling point to me was the 505 being a low resonance compression driver.. there just aren't many drivers with a resonance in the 80 to 100 Hz range like this driver... I have just begun my playing, but am already quite taken by it... this driver and its 48", 150 Hz horn will likely be the last thing I change.. it sounds very good..." Hm, I dont really know about this, I heard a GOTO system with the GOTO 505 in the GOTO 150 Hz horn and I found it to go anemic in the lower range, I think a FANE M8, that I heard briefly during some experiments, would do better in this range with a similar horn. I dont think it is a coincidence that GOTO systems sometimes have two parallel drivers on the lower midrange horns.

Be,

Do you think that that based upon your experience with GOTO and FANE it might be possible to generalize “what is better”.  It is upper bass and it is upon many valuables: Imbedded Macro-Positioning, appropriateness of a given horn to the given driver, specifics of the given implementation of driver loading, specifics of the driver electrical damping by amps, a listening ignorance of a person who implemented a given solution… and many other factors. So, the specific positive or negative results (or a result as in your case) are not indicative to illustrate of “what is better”. I am not willing to pretend that I know an answer to the question “what type of driver is better for upperbass”. Let us to think at the subject together from slightly more divert perspectives.

The debate as I understand is about: to use a compression driver or do not use compression driver for upperbass. The people around Steve Schell circle love to drop tears that “there is nothing like bass from a compression driver” (link). I usually laugh when I hear that pontification. I also whenever I hear upperbass from compression drivers never found it even worth criticism – it was just very bad, including what I heard from Steve Schell demonstration. Still, I would not accept is as defeat of the compression driver for bass notion. Let look what we are actually debating.

The people who uselessly use compression drivers for upperbass practically never use the compression drivers properly. The bass-able compression drivers with low Fs are rare. People have the only one type of the horn that the can afford space-wise for upper bass and they got those rare and expensive compression drivers. However, there a compression driver has ONLY ONE already SET resonance frequency and it have the only one optimum horn for that frequency. No one I know consider it and peoples juts plug the compression driver “as is” into the horn that they have. No one will pay $$$ for GOTO drivers, build horn and… then take a blowtorch and blow away the GOTO’s back chamber, biding own back chamber with the Fs characteristics that would be necessary for a given horn. Be advised that with new acquired Fs characteristics the GOTO (for instance) diaphragm type and suspension might be not winning anymore and we are talking about the new completely open Pandora box for multitude of dilemmas.  There is also a diminishing return with compression driver bass. We have 3”-6” diaphragm the need to push 300Hz. It does it and we call it OK. Then we need the same 3”-6” diaphragm to push 80Hz. The dimension of the diaphragm in compression driver does not wary a lot and in order the 3”-6” diaphragm to push more bass the suspension should be softer and the cone’s excursion should be longer. So, we produce more bass by let the diaphragm to run furthermore but it has a LOT of potentially bad results. The longer excursion means the gap should be with less tolerance with more flux wasted.  The longer excursion means more mechanical contribution from the cone and it’s suspension to the drivers. The longer excursion means the compression of the front chamber impact the cone more different at the beginning and in the end of the excursion. I mean the low excursion is one of the main advantages of any compression driver – we do diminish this advantage what we go in bass region.  Also, we do not know how the given driver’s cone will break-up when it is dumped for a given horn. I do not support the bogus believe about the piston motion of diaphragm – the REAL sound is create inside the diaphragm break-up…

Ok, on the other side we have my Fane-type of application for upper bass. The application is call to found as proper cone driver with necessary characteristics and to use is as a compression driver. Pay attention: it is not a cone driver loaded into a horn, it is according to all definitions’ is a compression driver application. What is the difference with the GOTO approach? The difference is that by selecting of the driver, type of the cone, type of the suspension, the driver performance at the given cruise dumping, size of the driver,  mass of the cone, way to damp the driver and many other characteristics we virtually reconstruct the compression driver, only we do it with respect to our given horn.  It is important to note that in both cases we are screwed: in GOTO-type case we’re screwed with fixed design of a compression driver and in FANE-type case we’re screwed with deficiency of good drivers for our specific application.

The funny part is that I never was exposed to the results where both: the Fane-type and GOTO-type were implemented in horn properly in respect to own topology. I would be no surprised that in the case of proper use the GOTO-type approach and Fane-type approach would perform identically properly. After all, the famous Russian writer Leo Tolstoy once said “All happy families resemble one another, each unhappy family is unhappy in its own way.” Why do you think it should not applicable to the ways to get upperbass from horns?

So, I feel that there is no “better way”.  I am a big fan of compression drivers but I feel that lowering the frequency where compression drivers are used the amount of efforts to get the proper result increase in geometric progression. There are solutions for all problems I have mentioned above but at some point it becomes a pursuit of a concept for the sake of concept. The best way is to have Mr. Goto or somebody similar to built custom drivers to your own specification but I doubt that this task is accomplishable within one life span as it takes years and years to understand Sound and how to create it… unfortunately...

Rerurn to Romy the Cat's Site