95Honda

Yeah, I am still in Germany.... Reversing the input power shouldn't have blown those, I was just curious either way...

BTW, did someone accidentally hook up the power backwards to the amp?

There should be a number on them like "D4007" or something like that, see if you can find it. I have literally thousands of semiconductors laying around, I'll just mail you one (or a suitable sub) if you give me the part #

Are you going to buy the Dodge through AAFES?

Also look into Audio Control, you can get some of their higher end stuff for that used....

Just remember, you can't measure impedance with any multimeter on it's own..... Only DCR, which is NOT impedance....

Dual 4 is what you want, you have to build a 2-way passive crossover, or buy this one like this- Subwoofer Crossover 4 Ohm 130 Hz 200W | voice coil subwoofers subwoofer crossover subwoofer subs sub woofers sub woofer sub power dual voice coil Crossovers coils COIL 4 ohm crossover-41108 Crossovers123008 | Parts-Express.com If you can't put the sub near or between your mains you may need a lower crossover point to help you not localize the sub... You run both voice coils seperately, one off of the left main and right main out of your reciever. The crossover filters everything below the crossover point to your sub (while presenting a 4 ohm per channel load) and everything above the point to your mains (presenting whatever your mains impedance is as a load). Super simple. Before someone says something stupid about this, this is how about a million passive subwoofers have been working for the last 20-30 years... lol....

They weren't sealed, IIRC... Just go to the battery rack and find the biggest ones, last time I bought several, they were around $100..

The big-ass 1000CCA+ yellow case batteries at Walmart. Honestly, if you buy anything more expensive, you are just trhowing away your money. "Car Audio" batteries are comparable to buying $8+ per foot 1/0awg power wire... "Car Audio" batteries are a rip, especially for the amount of time most people keep something in thier system. And reliability? WTF cares, you can take that bitch back in and exchange it for a brand new one as many times as you want for a few years.... Hell, we used to swap them out before shows... lol...

What happens if you enter the number by measuring from the mid points of the surround?

There is usually only 2 ways to ruin the voice coil. I know there are some people out there that have even found more creative ways, but this is it most of the time. #1 mechanical failure (when the former hits something). This can change the shape of the coil and cause rubbing, shorts and opens. #2 Thermal failure (when the voice coil actually breaks down due to heat). This happens because you apply more power to the voice coil than it can dissipate. This has nothing to due with anything other than too much damn power. Not clipping, not gain setting, not "dirty watts" just too much damn power.... #1 is usually pretty easy to identify as you normally hear a loud "clank" #2 doesn't happen immediately and is probably the most common..... Both of these are only caused by user error....

I think it should be the diameter meaured from roughly 1/2 way into the surround. But I would email Parts Express to be sure.

I just don't agree with you guys. I have modeled many drivers similar to the BTLs over many years (mostly MTs) and I have never gone with a small box with a small vent, when I run the paramters of the early MTs I always ended up with large volume vented enclosures, never the "crappy small box with a little port" or sealed like I always hear will be modeled. Maybe it is because I know the programs well and have built many, many enclosures over the past 20 years and measured a fair share of them rarely getting results that were way, way off of the predictions. I just know from experience that you can model drivers, and if you know how to interperet the results, you can succesfully design something that meets your goals without surprises. As far as system impedance (this isn't "impedance rise" as this incorrect term is always used) you know what determains a majority of it is the various resonances as a whole the system has. If the resonance points aren't changed, enclosure shape and proximety to nearfield items does little to change anything... This is always true unless you have a gross change in shape or something so extreme that is doesn't behave correctly at all in the first place. I think too often in car audio where many people don't fully understand what is going on (I am defiently NOT refering to NDMstang here) and they fall into the "it just works that way" or it is some kind of magic BS... When in reality it isn't, in fact many things can be reliably predicted, again, if you know how to properly use the equipment at your disposal. But hell, even back in the early 90s when friends of mine had MLSSA and IMP to measure, we used to build subwoofers and bring them into our audio meetings and measure them, hell Dan Wiggins used to build stuff and bring it in... And even back then, when we didn't have anything close to what we have now, we were still able to reliably design and build stuff. I just don't see how this has changed. Anyway, we'll probably never agree on this, but that is OK, we are here to offer our different points of view. This is all I have for this thread. -Mike

When you measure the resistance of your power and ground paths, you should read almost nothing more than the resistance of the thin test leads that came with your meter. If you do, you are either measuring wrong or something is seriously wrong with your install. Even 4 gauge power cable (which is pretty much considered a bare minimum for anything) in a 20 foot run has almost no DC resistance when it is cold...... At least less than almost 99% of the multimeters and test leads people are using.... Additionally, you should see zero mesurable resistance across any of your connections with all but the most advanced test equipment. Again, if you see anything even approaching 1/4 ohm or so, you have a bad install....

The whole point Vance Dickason made, installling the enclosure in an automobile did not change the tuning, Q or impedance in any signifigant way. It is cabin gain that really introduces the changes in response. Additionally, there probably isn't anyone on here that has measured cabin gain accurately (including myself). This would require a refence source and accurate measuring equipment. So when we are talking about changes in the few dbs or Hz, we are pretty much taking a stab in the dark when we blame it on anything but cabin gain. There isn't anything magical about loudspeaker response. T/S parameters can accurately predict the response of a loudspeaker. These calculations have been refined over literally millions of man hours over the last few decades.... When I hear things like "you can't model these drivers" all that tells me is that when modeled either the response is missunderstood, or, they have just been modeled wrong or all the modeled parameters have not been taken into account (like group delay and phase magnitude). This is also where a huge amount of the subjective sound quality of vented vs sealed debates stem from..... Or, more precisely, the missunderstanding of the whole subject...

That was exactly my point...

Actually, this couldn't be further from the truth. Vance Dickason did a complete experiment with this (as written up in his 6th edition) by measuring the complete T/S and enlclosure parameters of a few subwoofers in and out of vehicles. He also placed them in many positions. He could not get changes in the box parameters of more than 5% or so..... In other works, tuning, Q, impedance all stayed the same. The biggest difference in a car is cabin gain, but that doesn't alter the original box behavior/parameters in the least.... FI drivers are no different than any other drivers, if you have accurate T/S parameters, you can get predicted response just as you can with any other driver....

Why are you trying to measure it?

I would buy an extra recone, honestly....

Negative.

My 4 Auras....

The 2nd gen of the original bad boy..... Like I said, I used 4 of these... They were devasting in the huge auditorium I had them in... Aurasound NRT18-8 NRT18-8 Pro Sound 18" Woofer NLA from Madisound Also, another long time bad-ass super efficient 18 that is truly a subwoofer.... I have used 2 of these before, they are awesome, but again, real expensive.... http://www.mccauleysound.com/accessory_overview.cfm?ID=126 This stuff always gets me thinking... I just want to build a wall with 2 or 3 nice efficent 18s and power it with around 100 watts..... And just destroy people....

If I had to do a single sub, high efficiency set-up right now, I would use the TC sounds version of the Aura NRT18 prosound driver. I has a low Fs, a ton of stroke and real world 1w/1M 94db+ sensitivity... And dual 2 ohm coils.... Only problem is, it costs over $1000... But I would say that is probably the highest efficiency sub you could really get right now that would be right at home in a car.... Besides maybe a McCualey 6174..... Which I have used in the past, bad motherfucker also... The only problem when you start looking at subs that push the 100db 1w/1M threshold is that they aren't really subs anymore. Fs goes way up, stroke goes down...... They have to give something to get something.... http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-674 Put it in a 10+ ft3 box tuned at, I dunno 50 or 60 Hz with a vent you could walk through and 100 watts would be retarded loud.... I built a pair of subs using 4 of these 18s and used 1000 watts per woofer... It was crazy... I know TC doesn't list the Spl as 1w/1M but the original NRT18 was rated that way (I need to see how thay rate it) and was even higher..... I don't think they dropped the efficiency too much.... If they have, then this whole plan doesn't work, lol...

Just don't waste your money on the Knu aluminum junk..... Best cable marketing gimick in a long time...

Honestly, the only one to blame with this is the end user. You can't really blame Hifonics considering what you paid. Once you step into the realm of some of this equipment, you are asking for trouble if you don't know what you are doing. I compare it to sportbikes.... 17 year old kid buys an R1..... Totals it 5 days later.... Who's fault is it? The bike, no.... Same kid buys a Vespa, rides 5 years without a problem.....