I apologize for being away from this discussion string for several days. Indeed this is a very thick topic that merits further attention.
Cone resonances are almost ALWAYS called such incorrectly, that's because unless you have (like I mentioned earlier) one of those uber-expensive, super slow-mo, mega high-res cameras to watch cone movements you're speculating as to the cause of any irregularities.
Exactly!
As far as what you're trying to convey about air resonances, I don't get it. Are you talking about the air inside the pole? That's all I can think of ... unless you're meaning some sort of cavitation effect off the front and back of the cone face as it travels through the air.
I am taking about the air contained inside the "cup" of the speaker cone.
Do you find that perceived midrange dynamics, detail and clarity are also, in part, determined by crossover point/slope (turning more upper midrange over to an appropriately-selected "tweeter"),
Yes, but this is a compromise. What exactly is "appropriately selected"? Generally a tweeter will perform better and sound better at 2500hz than a 7" midwoofer. Certainly the SS9500 will handle monster power and a commensurately lower crossover point, but it doesn't have upper frequency detail present in the SS9900, Raven R1, or Hiquphon OW1. Further, A few folks have performed listening tests between the OW1 and OW1F. The results are mixed, but there is a partial sentiment conveying that the OW1 has slightly more more sparkle and air. So, while the OW1F will handle more energy due to the very thin layer of ferro fluid placed between the voice coil and the top plate, this fluid also damps the movement of the tweeter slightly. So... the drivers' must be used as they are intended and the crossover point/slope should accommodate them. Oh, and there is the issue of power handling too. Obviously a tweeter crossed higher will endure more energy.
as well as # of drivers used (single/mtm/array - does a more limited cone excursion "demand" matter?) independent of the intrinsic qualities of any given midbass driver?
IMO - Yes, I think that more drivers or a lesser load per driver will result in better sound quality. BUT, spreading the power across many lesser drivers will NOT produce the favorable sound quality present when using fewer drivers of very high quality. Given $500-1000 in drivers, my choice remains rooted in building a good 2-way for hifi listening. Sure, some bigger woofers in a 3-way will produce more spl, but there are $$ sacrifices that must be made elsewhere that are undesirable IMO.
Given an unlimited budget, I think an 10' line array of Accuton C95 woofers adjacent cut-flanged OW1 tweeters would sound dreamy in my living room. Unloading the bass with an array of TC Sounds woofers might be helpful too, but I suspect that sharing the power handling load across the C95 woofers would already be quite adequate.
In the grand scheme of things, there are many ways to tweak a system for better sound quality. Some of these things are very apparent and very marketable. However, the marketable things may not be a good $$ value. In terms of value, the cost of adding a woofer (to a 2-way) or creating a line-array is a considerable distance down the slippery-slope. Sure, there is some gain, but at much greater cost than other items that would improve sound quality.
This subject is very interesting but I agree with TurboFC3S, you have to further explain what you name "air resonance inside the cone".
Is it a resonance due to the geometry/shape of the cone, is it a resonance of air molecules inside the cone material or something else?
The air resonance inside the stiff cone is rooted in the cone shape. When the 1/4 wavelength of the frequency is short enough to reflect inside the cone it will "bounce". A cupped cone will have a defined resonance. In the case of the Accuton C95 and SEAS W18 this resonance is more visible because the surround is designed to create a pinch-point immediately below the resonance frequency.
I calculated the speed of sound into the cone materials from accuton ceramic (al2 o3) and seas magnesium:
- accuton: near 9000m/s (more density but a very higher stiffness)
- seas: near 5000m/s (less density, poorer stiffness)
Maybe this criteria could explain less stored energy in the accuton (at least the new range one which seems to be more accurately designed vs the older ones)
This is something I didn't address, and beyond the fringe of my knowledge. I really don't know how the speed of sound through the cone material would have an audible impact. Hmmm, perhaps the speed of sound in the cone material can be used to describe cone resonance. I really don't know. I have heard folks convey information regarding the speed of sound in the cone material previously, but have never heard/read anything tangible regarding the results.
Dave
