95Honda

Please do your homework before you pass on missinformation like this...

Those amps would be louder with those BTLs than any other 15" subs made by FI, or most companies for that matter...

Let me get this right, you are comparing the output of a pair of L7 12s to a single BTL 12, right? With the same power, right?

T/S parameters are the single most important indicator on 1) how a driver will (should) sound and 2) the required alignment... You can put any sub in a ported box and make it loud, that doesn't make it right.....

You can't really say for sure the resistance. If the load of the radio changes, the voltage dropped across it will change also. So if you figure out the resistance needed to drop to 5V under full load, it will not work when the radio is idling or not pulling as much current, in this case the volatge might be to high. The only time a resistor will work is when the load stays the same resistance (because you are building a voltage divider)... Most audio equipment doesn't work this way. Buy a small DC-DC converter, they make them that plug into the cigarette lighter for around $10-15.

I bought a pair of the 1000w Parts Express sub amps and posted some pictures of the guts on Forceaudio if anyone wants to see what they look like before taking the plunge. Enjoy..... http://www.forceaudio.com/showthread.php?p=3404#post3404

Here are a few of the pictures..

Yeah, your right, WTF do I know.... LOL...

LOL... Have either of you ever tested any of the P/E amps? I have. Objectively. Every one I have tested has made, or came within a watt or so of it's rated power. I tested the 1000 watt plate amp (same guts as the rackmount) 3 years ago. I did the test right. It was done into a load bank of precision non-inductive resitors and voltage was read with an accurate meater and distrotion was measured with an HP 339. Line voltage set with a variac. The amp does 1000 watts. I paid $600 shipped for the pair. You can't beat that for 2000 watts of non forced-air cooled power... Whoever got 580 watts either had a broken amp or was a moron.....

Again, port area has absolutely nothing to do with box size. It (the minimum size) is determained by driver displacement and the amount of compression you find acceptable. Additionally, a larger port will NEVER cause there to be less control of the woofer. The only downside to a port that is (grossly) too large will be that pipe resonances can set in and cause weird issues with the tuning. As long as the port is the right (proportional) dimensions, it will act as a Hemolitz resonator (correctly).... I don't know why people keep making this crap up...

Well, apparently not in your case.... Or you had more than 1000 watts + whatever BP adds....

You probably have a ton of problems with your enslosure construction if this is an issue. For a quick fix used 1/4-20 hex head capsrews and T-nuts or hurricane nuts. I am not sure on that subwoofer's basket, if the holes won't accomadate 1/4-20, go with 10-24. Stay away from 10-32, as you will more than likely cross-thread one of them... I still would wonder about box construction though...

Ahh, it's rated thermally at 1000 watts...

I built this amp from scratch about 5 years ago. I also designed everything but the output stage... I weighs almost 100 lbs. It is a pretty sweet amp, it still runs like a champ day in and day out.... Class AB, 100wpc into 8 ohms, 200wpc into 4 ohms and 400wpc into 2 ohms..... So, I went ahead and cleaned up some of the crap I did about about a year ago converting my amp for 230V and adding grounding options... I added a 5 position barrier strip with selectable jumpers on the input side for setting up the primaries of the power transformers for either 115V or 230V.... I also extended the primary wires about 10" to reach the barrier strip. Next I added small toggles to select either chassis ground or float for each channel on the RCA jacks.... I haven't needed to use this feature, but it is always nice to have. I also added a serious ground lug to the back and ran it to the star ground... I doubt I'll ever need that also, but hell, who cares.... All politically correct audiophile wiring, of course.... I even used silver solder (total waste for power wiring but, hell, this is my statement amp so who gives a shit...)

Thanks for the comments. I wish you could see it in person, the pictures make it look like ass.... I just ordered a pair of the 1000 watt Dayton rack-mount subwoofer amps to power my XXX18s. That is my substage in the house... I am going look into a Krell KRC-2 (used) premap as the last bit of the system, other than a new Blu-ray player....

I am not trying to prove people wrong BTW, I am trying to keep missinformation off this board.... Thats all....

Youtube... Now thats Objective, LOL! This is pointless trying to explain to some people.... Obviously you still haven't read the clipping test on Forceaudio....

No it's not, and no you haven't. Perform an objective test as I have and I will recant my statement.

LOL, beat me to it! And before anyone gets thier panties in bunch, read this- http://www.forceaudio.com/showthread.php?t=15 Pay close attention to the NORMALIZED power results....

And you have proven this theory, how?

The BTL is a much more efficient driver. It is also geared more twards SPL.

You can blow that sub, and almost any sub for that matter with that amp. If you send too much power to the sub, you will kill it. Period. Until you have your box completed, nobody here can tell you how much power your alignment will handle. And even if you build a box that has the mechanical power handling for that amp, you can still fry the sub thermally.

It is real easy to make it objective... You need to put both drivers in the exact same alignment, not enclosure.... Sometimes we forget that there aren't two drivers on the planet that are completely optimized for the same exact enclosure. In fact, even identical drivers (same model from same company) will have variations in T/S parameters that would require slight adjustments to achieve identical responses. I have witnessed this first hand when optimizing crossover networks and having to tailor each speaker independantly to achieve identical measured response, and this is with identical drivers.... That would mean identical Qtc of sealed boxes and identical Q and alignment type of a vented box. When you do this, neither box will be the same size, have the same vent dimesions/proportions or the same tuning. It is commendable to take the time like you have, but the results would mean so, so much more if you placed the drivers in identical alignments.....

When you use the same ported box for 2 different drivers, all objectivity is out the window....

The flares help, but not as much as everyone makes them out too.... If you need a 4" (non-flared) port, and you decide to go with a flared port, you are better off still using a 4" flare port.. And the vent area is NOT determained by box volume. Ever. It is determained by the displacement of the driver. The more air you displace, the more port surface area you need. If you run that 18 with roughly half the power, only 2 ports would be fine. If you ran it with roughly a quarter of the power, 1 would be fine. The only way to answer your question is to model the driver in that box with your predicted power and look at the vent velocity, if it is low enough, you'll be fine... And the quick answer, 4 x 4" ports are fine for almost any 18" driver under most circumstances....