MPS-2500 + 2 Interfire 12" DVC = What?

[Eric D]

But none of this has anything to do with the amplifier's load, just the amplifier. And the PWM controller which directs the power supply should maintain an output which is a ratio of the input voltage (depending on the design). Yes indeed more heat means more resistance, but if the PWM controller adjusts the operation of the power supply to compensate, then you still get the output you are after. The amplifiers operation is not a "fixed" system. It can and will make internal adjustments to its own operation.

At some point the PWM controller will run out of pulse width to add, and then you might have the output of the amp sag. But, chances are the amp will either run out of input current first, or hit a thermal point where its protection shuts it down before the PWM controller ever maxes out.

[Shinju]

Just buy a bunch of these Hifonic subs and call it a day!

http://www.amazon.com/gp/offer-listing/ ... nk-c953-20

there is a 150.00 dollar max SPL contest on CA.com that you have to buy all new equipment to participate in (not saying you need to) but alot of guys are buying these up like crazy and getting some interesting numbers from them.

Interfire stuff is meh never ran it but I always see it in pawn shops more so then DUAL brand so it must not be all that great!

[Shinju]

Its the Golden Ones Phoenix Gold Magical Watts hour!! HOW DARE YOU QUESTION IT! /wink

But none of this has anything to do with the amplifier's load, just the amplifier. And the PWM controller which directs the power supply should maintain an output which is a ratio of the input voltage (depending on the design). Yes indeed more heat means more resistance, but if the PWM controller adjusts the operation of the power supply to compensate, then you still get the output you are after. The amplifiers operation is not a "fixed" system. It can and will make internal adjustments to its own operation.

At some point the PWM controller will run out of pulse width to add, and then you might have the output of the amp sag. But, chances are the amp will either run out of input current first, or hit a thermal point where its protection shuts it down before the PWM controller ever maxes out.

[The Golden One]

it has to do with the "GOLDEN RATIO" you wouldn't understand http://www.mathsisfun.com/numbers/golden-ratio.html

[interestingfellow]

Phi is phun.

And you're absolutely right: the formula does apply, but it also doesn't matter cause the amp adjusts itself.

And, I got 2 of the Interfire subs for $130. Designing box now, I'll report back after I get them in and I fire'm up.

[oldschoolfan]

I have been instructed by someone I trust, to always allow at least half the diameter of a speaker worth of distance in front of said speaker. So for your 12" subs you would want at least 6 inches in distance from their face to a solid surface. This is supposed to prevent pressure created by the speaker on the outside of the enclosure from working against the motion of the speaker.

In short, it can negatively effect the tuning of the enclosure by having the face of the speaker too close to a solid surface.

[Eric D]

I have been instructed by someone I trust to always allow at least half the diameter of a speaker worth of distance in front of said speaker. So for your 12" subs you would want at least 6 inches in distance from their face to a solid surface. This is supposed to prevent pressure created by the speaker on the outside of the enclosure from working against the motion of the speaker.

In short, it can negatively effect the tuning of the enclosure by having the face of the speaker too close to a solid surface.

I was taught the same thing.

[00goobs]

I remember reading somewhere that having a wall or solid surface about 3+" from the speaker makes for better efficiency. Similar to a bandpass enclosure I am guessing... The post was actually comparing it to a compression driver...

[interestingfellow]

Ehhh, I didn't want to go against the grain, but yeah. the 1/2 the speaker calc is good for general clearance but there is the whole reflector/baffle thing to consider, too, IMHO.
I couldn't find any formulas for it though. I had planned on firing them down, into a "baffle area" (the floor) and the bench seat bolted to the top. Dunno. Take a look, the calcs are for the box being 24" deep.

Also, I'll be recarpeting the van, and I really want to use some thick plush carpet (like, for your house).

I'm counting on all 3/4 inch mdf
The speakers chamber is just a regular rectangular prism, and the vertical piece between the subs (under the "50-1/2") will be a 6x6x3/4 centered in the box for support/resonance. The center leg will actually be 3x3, 1 in the front, and 1 in the back (keeping an open airspace between the speakers in the baffle area). FWIW.