Question about subwoofer sensetivity and underpowering

[Vincent Infante]

I currently have a pair of Kenwood KFC-W3013PS subs in a ported box. The box has 1.85 Cu. per sub and the port is tuned to 38Hz. The subs are rated for 400w rms each and i have an amp that supplies them with 400wrms if power. I want to replace my subs with Pioneer TS-W3002D4 subs rated for 1000w rms but i cant afford to replace everything at the same time. Im considering buying the pioneers and running them off of my old amp until i can buy a amp that can fully power them along with upgrading the cars electrical system, adding a large capacitor, and possibly replacing the box with a sealed enclosure. I'm thinking that because the pioneer subs have a sensitivity of 90dB and the kenwood subs have a sensitivity of 85dB that the pioneers will be louder than the kenwoods with only 400rms of power per sub even though they are extremely under powered. Am i correct to assume that? Does higher sensitivity literally mean it will be louder at the same power level? Also if i am underpowering dual coil subs, would it be better to only use one coil per sub?

[kingsuv]

easy answer is no, no and no.

There is no such thing as "underpowering" a sub. There is such a thing as having a little amp maxxed out and clipping the shit out of your subs. Sensitivity doesn't relate too well in an actual application. It not enough to hear the difference in most applications. Never run just 1 coil in a DVC sub. It is a quick way to ruin the sub. You can run higher power subs off a smaller amp as long as it is set up correctly, and that you understand the gain is NOT a volume knob.

[Vincent Infante]

i have my gain set perfectly, used a portable oscilloscope and it distorted right at 3/4 gain so i have it set a bit under 3/4. thanks for the advice about running off of a single coil, ide hate to ruin brand new subs before i even have the correct amp and electrical setup xD. I misunderstood at first what you were saying at the end but i understand now that you are saying that a small amp with a high power sub is okay if the gains are set right. i have one more question, these subs have a recommended max enclosure size of 1.6 cubic feet. What kind of effect would having these subs in a larger box have?

[sayhuh?]

easy answer is no, no and no.

There is no such thing as "underpowering" a sub. There is such a thing as having a little amp maxxed out and clipping the shit out of your subs. Sensitivity doesn't relate too well in an actual application. It not enough to hear the difference in most applications. Never run just 1 coil in a DVC sub. It is a quick way to ruin the sub. You can run higher power subs off a smaller amp as long as it is set up correctly, and that you understand the gain is NOT a volume knob.

One coil? You can do it without ruining the sub, unless you are stating what you are due to people pushing rated RMS to one coil. I was taught if you run one coil, you should only run about 40% of sub RMS. This not true?

[Vincent Infante]

if i were to run it on one coil it would be 400wrms to the coil which is exactly 40% of the subs rms rating

[bkolfo4]

It won't hurt the sub to run one coil, but the added magnetic field of running both coils will probably give you more output, even with them wired in series at 2x impedance.

Sealed vs. port will be a significant reduction in output, unless the ported design you have sucks.

As far as the efficency at 1 watt - you have to look at more than that one parameter along with the box alignment to determine which design will seem louder to your ear. The higher efficency sub may be louder at a much higher frequency. If it is, it may not seem as loud as the lower efficency sub to your ear playing music.

[kingsuv]

Actually yes you can damage a sub running one coil. See coils are wound on top of each other. and we all know metal contracts and expands with heat. So you can spider a coil right off the former. But I guess 1st hand experience has no part in it

[bkolfo4]

Be interesting to know if you had been running both coils if you still would have damaged the sub.