Normalized, yes, but i'm not so sure about the low part.
Normalizing just gives a basis of comparing across drivers. Say the raw number is 3mH. The effect of that is rather different on an 8Ω voicecoil compared to a 1Ω vc.
I think as long as inductance isn't ridiculous, it matters more that shorting rings are employed rather than absolutely low inductance.
The TC3000 is convincing evidence that shorting rings alone aren't enough. Though you don't preclude that with your analysis, if you consider its inductance to be "ridiculous."
I do share your general intuition that Le(x) variation is more significant than static Le, though.
I think my mal-x gen 2 with around 4mH of indutance is avtually very good higher up in frequency.
The Mk. II had a single 4Ω coil, right? That puts it at about 1mH/Ω. Not too high. Though I like my preorder Mk. I's almost Aura-like ~.22mH/Ω better.
he was implying that a setup such as yours would be limited in the infrasonics because only the main woofer is really contributing to deep headroom.
Which is simply wrong. All of them contribute, because in the "first mode" (~40Hz down) region where subs are often xmax-limited rather than amp limited, they sum in phase. "Deep headroom" is only limited by the sum of the individual volume displacements.
Consider that at 20Hz S1 is capable of a modeled 100.5dB at xmax, S2 is capable of 94.2dB at xmax, and S3 is capable of 92.9dB at xmax. The in-phase sum of those three values is 106dB. That's a lot more "deep headroom" than S1 alone provides.
Only this system, because the load is spread over 2 3" voicecoils with their own cooling systems and one 2" vc, is likely to be closer to the modeled 106dB than a single subwoofer that models at 106dB/20Hz, because of lower power compression.
Others may well choose sub systems with greater combined Vd. Here, keep in mind that the mains in this temporary are 4.5" Uni-Q's in small eggs, so it's not like I need 115dB capability at 20Hz.
Because of the wide baffle, I'm not so sure. I think more relevant in that scenario is that the power response from the rear tweeter is kept consistent. The polars are mostly contolled by the 1.4khz crossover.
At which frequency the two tweeters will still have dipole cancellation, for an effective 90deg pattern.
I'd love to hear one using the RAAL 140-15D Dipole
I've seen no reason to suggest that it would better, or even equal, the Neo3 in that particular system. The Neo3 is more likely to radiate symmetrically, given its magnet configuration.
Sadly, on the overwhelming majority of of "high end" speakers, it is not. Here are the horizontal off-axis measurements for the most recent speaker on Stereophile's website.
I think a speaker needs wide dispersion out to at least 60 degrees, maybe even 70 from 1khz to 10khz.
You mean per side, so 120-140deg total? I'm not sure I buy that.
'm not convinced as far as needing declining sound power. I think "declining sound power" is just a translation for "adequate baffle step compensation" in monopole speakers and "drivers that can handle power in the midband and cross smoothly to other drivers".
No, because baffle step is much lower in frequency, and sound power has nothing to do with power handling or driver hand-offs.
I feel that flat - but (not omni radiation without the right placement) sound power + flat frequency response CAN in fact work.. it's just not possible with corrent drivers.
Try it. Flat sound power just sounds bright as hell.
Thanks for clarifying. I am intrigued by his differing approach.
If you're using Dr. Geddes' sequential setup approach, our approaches do not in fact differ. I'm just carrying the Geddes approach a step further back, designing each sub to have adequate capability for the actual role it plays in the combined system.
IOW, what does differ is that you're leaving a lot of output in reserve, because you're basically limited to the max SPL of the main sub plus much less contribution from the other subs. (I suspect the rest of them are down in level somewhere between -3dB and -15dB compared to the first sub, because otherwise you're not doing Dr. Geddes' approach of sequential setup.) By contrast, I basically designed my auxiliary subs to overload at about the same time the main sub does, considering the relative levels each one plays at in order to maximally enhance performance in the modal region.
