95Honda

There isn't much you can do about the group delay. Does your program show it? If it does, see how bad it is and if you can manipulate it much with tuning variations... If you look, you'll probably have 2 huge spikes in group delay at the lower and higher tuning points, with a trough (of still high group delay) in the middle.... The lower end tuning will probably have more group delay, but it isn't as audible down there. Where it gets annoying is 40Hz on up... Near the upper end of your pass band (drums, bass guitar, and such) you may get the results of muddy or sloppy sounding bass...

I have tested the following P/E plate amps into 4 ohm resistive loads- 250 watt plate amp, (the $135 one) 271 watts @ 4 ohms before visible clipping... I have used maybe 10 of these... Talnlanky's amp was the last one I tested... 1000 watt plate amp, 1003 watts @ 4 ohms before visible clipping 500 watt Bash, don't have anything written down, but I know it made its rated power before the onset of visible clipping... I can't vouge for any of the others.... I think sometimes people say they don't make rated power because of #1 sagging or low AC mains or #2 innacurate output measuring technique... All the P/E amps except the Bash (IIRC) have linear power supplies, if you don't have at least 120V of AC, they won't meet specifications.... I use a 2.5Kw variac with all my bench testing and set it for exactly 120V.

Then it should be fine. What most people don't realize is that there are literally millions of drivers being used this way right now. For those of us around during the single pasive sub and sattelite craze of the 80's and 90's (before power subs became popular) we have seen this before... In this application you often had a single dual voice coil driver having each coil driven by the left and right side of a 2 channel power amp. This would be two different, often very different signals. There has never been a driver that was destroyed because of this. Seriously, I think that everytime someone says the signals have to matched has no idea that this has been common place for so long....

It is the difference in time the different frequencies get produced (arrive) by the alignment, the more group delay you have, the worse things sound. Some people would call this transient response, it technically isn't, but you could describe it that way.... Group delay tends to be worse right above and around tuning, so thats two strikes against a 6th order right off the bat....

6th order vented tend to have pretty bad group delay.... One reason why Bose subwoofers sound so horrible... It would (could) be very, very loud though... You could use some FMODS, or even a passive high pass filter if bottoming out really became a problem... I have built a few 6th order BP boxes for home audio, I like 4th order better.... I copied that stupid Bose bazooka 12" sub, it sounded like ass but was loud...

I pulled them out of my rear-end.... Just as all peak ratings are....

I won't hurt anything. You just have to make sure they run out gas at the same time. If you have one that say starts running into clipping at 1/2 volume on your headunit, and one that does at 3/4, then it will start sounding like ass at 1/2 even though the other amps has some left in it. This is where you would want to match voltage if you could.... Now additionally, remember how I said the phase differences cause cancellation? Since those 2 amps are completely different, they may have signal processing (boost, X-over, etc) That introduces phase changes. If you have enough phase differential, your losses from cancellation could be greater than what you are getting with your power gains. So, unless you Really, Really, Really know what you are doing, it might not give you the results you are looking for...

I think most of it has do with the IXL's larger Vas, everyhting else being somewhat equal, this is where your efficiency boost is coming from...

What standard? I know they are at least 10,000 peak at 125ms, 20,000 peak at 62.5ms....

There isn't much too it really. There is a magnetic field generated by the coil. The more the current flows in the same direction through the wire in the coil, the greater the magnetic field. The greater the magnetic field, the more the cone moves. You could break the coil into infinite sections (like dual or quad coils for example) and feed each section current, as long as the current is going in the same direction (amplitude does not apply in this equation) it builds the magnetic field, it builds it additively. That's about it really... The voice coil windings can't "fight each other" because there is only one magnetic field generated, not two or more fields... If there are different phase relationships you will have cancellation, that is it. But that isn't ever the issue with matching different drive levels... The cancellation only lowers efficiency anyway. It doesn't cause overheating (we are talking only a few degrees of phase here) or anything wierd.... You won't ever have serious phase issues anyway, unless your equipment is broken. Even then, it still won't cause any damage unless you seriously try to.... People have made this up. Nobody has ever blown a subwoofer any faster because of different driver levels to individual coils.

This is 100% a myth. The outputs never have to be matched when running seperate coils with seperate channels or seperate amps. Either way you want to do this is fine.

What voltage and current did you measure right before clipping?

If it isn't an impedance matching issue, strapping two amplifiers together will never give you the same performance as running them unstrapped. Any time you bridge (strap) two channels (amplifiers) together you cut the amplifier's dampening ability in half.... Other small, but noticable performance reductions may happen. The ONLY time you should ever strap amplifiers is if your loudspeaker impedance is too high to get the power you want from the amplifiers when operated independantly... I think alot of people missunderstand this....

Yes, yes and ...... yes....

Actually, you can put "oversize" wire of any gauge into most loudspeaker terminals. You can buy solder/crimp-on ferrules that will reduce the end of the wire to a usable size. They make these so you can fit a 4 awg wire into a 10 awg terminal, for example... No, I don't have any links...

You can't hurt a BTL with a home reciever, at least not one that I have ever heard of. You may hurt the home reciever if the BTL impednace is lower (very likely) than the minimum of your reciever (usually 6-8 ohms) I don't know why you would do this unless you are running a passive crossover and running the highpass to your mains and the lowpass to the BTL voice coils..... Again, beware of minimum impedance.... If you had say a dual 4 ohm BTL (do they even make these?) and a reciever capable of 4 ohms, you could build a killer sub/satellite passive system with a BTL in a big box... Would probably be louder than anything passive you could buy sans a horn-loaded sub of some kind....

You could never run 8 gauge to the coil directly, you would trash the spiders, ruin the wire and have lead slap like crazy. It is just way to heavy and not flexible enough... If you want 8 gauge to the tinsel leads, like DD does, just solder them on yourself. It is a waste if you can get 8 gauge into the terminals anyway, you could't hear or measure a diference between soldering them on or a proper terminal application....

Welcome! And hello from the Pfalz...

#1, it doesn't matter what your gain setting is, you can always get full power out of that or any amp #2, you can ruin any sub talked about here with that amp #3, every signgle 18 on this site can handle that amp if you are carefull So the moral is, there is no correct answer to your question. Nobody knows how much power that amp will put out in your particular application. Buy your sub, build your box and use your head and you will be fine.

I guess I don't understand the connection you are trying to make. His white paper has little to do with the bulk of high the efficiency, large motor subwoofers discussed on this site (BTL, Havoc, etc). You also know that Bob has a way with words, right?

Gainmatching hurting the subs is an absolute myth.. I still don't know who made that one up.... You can drive one coil with 100 watts and one coil with 200 watts... It doesn't matter, all power is additive if in phase.... If it isn't in phase you have combining loss, and this also doesn't hurt anything. Period. You don't need anything fancy to do this, if you want, play a test tone and just make sure the voltage from each amplifier's output is the same. It could be any tone, at any frequency at any level, that part is arbitrary.... And the only reason you would match the amplifier's output is to be sure one doesn't run out of steam before the other....

If SQ is truly your goal, the Aura subs with underhung motors have less distortion than almost anything else you can buy.... The just cost almost $1000 for 15" The NRT 18 is a prosound woofer, but if you had room for an 8ft3 box, that would probably give you more low distortion bass with only a few hundred watts than you could get anywhere... Again, for about $1000 a pop.... 05' and earlier XXX subs (no longer made) Adire Brahma (no longer made) Those would be my top 3 picks of anything at any price, if SQ was truly the only goal.

Err, I think you misunderstood the white paper. Bob makes it clear his alignment is very inneficient, hence his 2700 watt amplifier... He also personally told me this about 13 years ago when he demonstrated the first prototype of this sub to me and a few others (Dan Wiggins was there, LOL)....

I think most of the disrespect was in the fashion the OP was written....

100% of the port can be outside the box, it doesn't make one difference at all... It actually makes things easier because you don't have to account for the port displacement with you box design...