noah katz

Hi Mike, "1) add mass to shift compliance;" I'm sure it was just a typo, but adding mass shifts Fs.

"... in normal, intelligent usage" huh?

You can get equivalent performance to a large unflared port from a smaller generously flared one.

A nice feature of the Soundsplinter drivers is the aluminum cone for its heat dissipation capability. I've never quite understood why all the supposed power people feed their drivers in sealed, insulated boxes doesn't cause them to burst into flames. Well, paper cone drivers, anyway. Has anyone ever checked how warm the cones get? Thanks

I seriously doubt the cone would get hot enough to be deformed by hand; I think that would have to be several hundred degrees, and if that were the case the VC would be toast. Bent, Isn't the BP an underhung design with huge xmax? Do you expect the RLp to be an improvement?

Are the drivers shipped from the same place regardless of whom they're purchased from, or they kept in stock locally? Thinking of shipping charges. Thanks

Mike, Just curious, how much of the Mms is just the voice coil? Thanks

That's one hell of a topic for an English paper; you ought to be able to recycle it for Physics or something, too.

The aluminum cone is something I like a lot. For the life of me I can't understand how the heat gets out of a tightly sealed, insulation stuffed box. I mean, I've made paint drying ovens with a leaky cardboard box and a 100 W light bulb. I can only conclude that the average power is inly a few tens of watts at most.

What are the voice coil diameters of the R-lp drivers? Are they based on the TC9? I thought I read somewhere that they were, but the T-s parameters are pretty different. Thanks

IIRC 1.25 lb/cu ft of fiberglass will increase the effective volume by about 25%, and decrease Qts, so you can really save some space this way.

Just curious, are you guys anywhere near when the measurements are taken, or do you wear hearing protection? I don't understand how everyone isn't deaf with the dB numbers you're talking about.

Will you be doing any measurements, and if so, outdoors to remove the effect of the car? Thanks

If they're measured properly, watts are watts no matter their source.

" however if you find that the sound is a little muddy I would suggest slimmin' down your box size " I suppose you mean muddy because of too much low bass? That could be EQ's out, or don't most car people use EQ? A smaller box will raise the Q and make transient response worse.

Mike, "3" voicecoil on the RL-p" Awesome. What's you're preferred way of being contacted about a quote on eight RL-p12/4's, and the possibility of getting surrounds from the 15" RL-s to build a bunch of passive radiators? Should I email you here or via soundsplinter.com? "does it really matter" It gives an indication of the amount of thermal mass in the voice coil assembly; the higher that is the less short term output compression there will be. Also there's more associated surface area for dissipating heat, which reduces long term compression. Mike, what kind of measures does the TC9 have for ventilating the voice coil area? Thanks a lot

"But I also don't think we are talking about a difference of that low of an order, after modeling it, it seems more like a Qtc of 1 for a near IB enclosure vs Qtc of 2 or 2.5 for a smaller sealed." A Q of 2.5 will *definitely* be sloppy from an objective perspective. A single pulse input will have the cone oscillating for many many cycles before decaying in amplitude. It may *sound* good on a lot of music, rich and full, but I can't imagine it reproducing real instruments, like drums, satisfactorily. Any Qts over .5 has some ringing (continued oscillating of the cone). .7 is normally considered optimum, giving more output and only a little bit of ringing. "High Q = Very little BL = Poor efficiency = loss of output with a given amount of power" Slightly out of order - low BL is the first in the chain of cause/effect. "but i thought the higher the q the smaller the box" Also backwards. Starting with whatever Qts the driver has, the smaller the box you put it in, the higher the system Q. "Transient response and energy storage shouldn

"The constant (or near to) BL? so on... This will explain quite abit of my point." It may explain why the claim for constant T-S parameters is well founded, but it doesn't explain why a (constant) Q near 1 won't give a sloppy, underdamped response. Could explain what you mean? Thanks Noah

Mike, Thanks for the welcome, you're a class act. Nick, "when You consider that the new & different things that the input voltage will be doing" Like what? You can say modeling programs aren't worth much, but if anything they err on the side of overpredicting performance. In this case they will predict a very underdamped response for any sealed box, and I think for any ported box as well. I understand what Mike is saying about tuning low to suppress the huge bump there'd otherwise be. But a ways abovie Fb the port is essentially plugged in an acoustic sense and the system behaves like a sealed one, which is to say in this case, underdamped. But all that is armchair engineering; maybe they'll sound wonderful. Although I don't see how they could be *accurate* compared to say, an XBL driver. That's assuming that XBL keeps Q as constant as BL; I'm thinking this answers Mike's saying that other drivers' specs may be one thing on paper but something else entirely when operating.

Sorry to rain on the parade, but I don't get it. Specs wise these look to be boombox drivers, not HT drivers, with their high Q and high Fs. The low efficiency combined with averagish power handling limits output. Starting from Qt near 1, it's impossible to even approach Qts = .7 Anyone using a modeling program would take one look at these specs and turn the computer off. It looks like everything was sacrificed to get a high xmax. But all that is armchair engineering; maybe they'll sound wonderful.

"1000W @4ohms for HT duty....prob looking at a good $1000+ for an amp" Crown XLS 400, 1150 W bridged into 4 ohms, about $250 on ebay.

"..i ran mine at 1200 off my orion 2500d for quite a while ported....no issues...and it gets 750 daily.." There's a BIG difference between what an amp is capable of and what the speaker is actually absorbing while you're playing music. Think about it - 1000 W is all it takes to get many feet of thick wire to glow red in a portable heater.

Two things: 1) My vote is for a 2-ohm VC. 2) I forget if the cone is aluminmum, but if it is, how about a bronze-colored anodized finish? Thanks