helotaxi

Back EMF distortion is the term. The inductance and EMF generated by the moving coils of subs wired in series causes a change in the signal going to the other subs in the series. Wiring individual subs in parallel allows the amp to act as a shunt for this.

With multiple coils on the same sub, series and parallel don't make a difference at all.

Where abouts and how soon? I'd rather not go into what I do. I'm not one of "them" but I do have a pretty sensitive job. One day I'll go into it a bit but not now.

I like a lot of headroom, too. 100w per channel is plenty of headroom for me.

Yeah, I'm one of the guys you're doing security for. I volunteered to do a short notice deployment back in October but it got canx'd at the last moment. I spent the next 3 months in limbo about whether or not I was going to deploy and really didn't know for sure until 2 days before I left. I've been extended twice on this deployment so far. Of course with what I do, being home is really no different than being deployed, I've been fighting OEF and OIF continuously for the last 3 years without a break except for my deployments. At least over here it's tax free with all the other bennies. I should come home with close to $15k in the bank and that's after I bought my HU, Legatias, the stuff to get my SRT-4 back to stock, an Orion XTR amp (for the collection), 3xSundown 100.2, 2 digital cameras (one got lost while traveling around the AOR) and an iPod Nano. I also signed my bonus over here and paid my motorcycles off. If I play it out right, I should be able to pull 9 months out of this year tax-free. Now if only I could get my wife's income to be taxs-free as well...

I'm going to be running 3 2-channels. I'd run a 6 channel if there was one that suited my needs. If you can find an older Phoenix Gold XS6600 it is a staggered power 6 channel. PPI made 2 a while back that were really good as well.

I'm in the process of getting all the components together for the SQ install going in my new truck in August. I'm trying to nail ldown the last piece of the puzzle, the bottom octave (or two). The vehicle is a 2007-2008 (there are still new 2007s around) Nissan Frontier King Cab. The system goal is accurate reproduction at listenable levels. The rest of the system consists of a Kenwood DNX-8120 (the wife insisted that I get the more expensive unit with the nav functions), an Altomobile Drive 30 (extremely powerful 6 channel processor that does filtering, time alignment, EQ and a few other things independently for each of the 6 channels), active front stage consisting of a set of Hybrid Legatia L31-2s (will be glassed into the a-pillars) and a pair of Tang Band neo 6x9 subs (in the doors). Front stage will be powered by a trio of Sundown 100.2s. The delima now goes to the subs. The plan is to build an enclosure that is right around the height of the rear jump seats and use the jumpseat pads to disguise the box to keep the install as stealth as possible. This steers me toward 8" subs firing forward with a removable grill covering them. I could do 10's or 12's downfiring, but, between the mounting depth of the subs and the space needed to clear the floor in a downfiring config, the height ends up right about that needed for 8s but with a larger box requirement. Since I'm only really needing the subs to take care of 50hz and below, cone area is important, so 3-4 subs will be used depending on coil config. I'll probably be looking for a sealed setup for reasons of enclosure size and accuracy. For power I have a Sundown 1500D that will be more than enough power for what I want. Here are the subs I'm considering in no particular order: Sound Splinter Orphan 8 (x3) Pros: Tiny box, should be able to handle that bottom octave with some authority Cons: Discount price ends before I'll have all the info I need to make a decision, will allow the least headroom from the amp JL 8W3v3 (x4) Pros: Small box, JL reputation (I've always been impressed with the JL 8s), readily available, should be able to handle the bottom octave well Cons: Not inexpensive, might not like the power I have on tap (I'd have to dial down the gains for sure) JL 8W7 (x3) Pros: Will kill the lows, will like 500w each Cons: Most expensive option (by a pretty good amount, I'd probably spread the purchase of these out over a few months unless I found a dealer willing to hook me up for buying 3), need a pretty big box (but the fact that there's only 3 helps a bit) SSA 8 (x? depends on coil config available) Pros: Keeps it in the family (as it is right now all my major components are SSA member products), great reputation Cons: A lot of unknowns (including release date and cost, but I'm not goin to make a decision until these are finalized or I'm headed home) Ascendant Audio Assassin mk1 (x4) Pros: I already have the 4 that I would need, tiny box Cons: Worried about the bottom end in a sealed box Dayton RSS210HF-4 (x4) Pros: Fairly inexpensive, should be one of the best on the very lows Cons: Not sure how they'll like the power (though not too worried), probably want the largest box That's the rundown as I see it. If anyone has any insight or anything that I'm forgetting, that's the purpose if this thread. Cost isn't a huge factor. I buy good equipment and keep it forever so I don't mind spending money for good stuff. Remember I'm looking for an accurate driver that can get low. Output is not much of a consideration at all. EDIT: didn't realize what a book I'd written...

For us old heads, we knew immediately that he was in fact talking about IB when he said "free air." The terms used to be used pretty much interchangeably in the car audio realm.

Woven cloth sucks for going around curves if you're using a heavy enough cloth to build up any thickness. Trying to do the whole thing inside the trunk will be VERY difficult because at some point you have to enclose it meaning that you have to finish working from inside the sub cutouts. Sanding it will be a real turd, and it will have to be perfectly smmoth to get a carbon fiber finish layer on it. Not to mention that if you want the carbon fiber layer to come out right, you have to vacuum bag it which can't be done inside the trunk. It would look cool but it would be basically impossible to pull off.

300w on an 8 is pretty much all you can expect one to handle. The cone is so small that it doens't benefit from enclosure loading nearly as much as a larger sub can, so while there are 8s out there that might be able to thermally handle that kind of power, mechanically they'll get beat to death in a sealed box. If SQ is your focus, cross off the MA Audio and RE subs. They are not in the league of the others. I'm not sure what Eclipse model you're looking at but they used TC Sounds (Audiopulse) as their OEM for their high end subs, as did Sound Splinter. The SS subs are not availiable for the foreseeable future. Most people on here hold the owner of eD in less than low regard, but I won't get inolved the that bit of e-drama. No experience with the Treo subs but I've never heard anything bad about them. DD can get loud, not sure how they'll do sealed in that airspace. ID isn't going to like that kind of power. What are the dimensions of the space you have to work with. If you could find 2 subs that could work in that kind of volume, would you have room to mount them? What vehicle? What mounting location? You might be surprised where you can fit subs. Giving us some of those answers might allow some of us to come up with some ideas that you haven't thought of to go with something different or bigger.

So what if Hifonics are overrated? I fail to see how putting out a few watts shy of advertised bench specs in the real world makes it a bad amp when it is still a really good deal for the amount of power that it DOES put out. Tell me which amp is a better deal: one that is rated at 200W and does 500w and costs $300 or one that is rated at 600w does 500w and costs $275? Way too many poeple get way to wrapped up in the rated vs actual power thing rather than the actual power vs price thing.

I was supposed to have been home a month ago...oddly I have another month and a half to go.

What whole system amps does your shop carry? That could have something to do with it.

Not much of a step really. Been running a '03 XXX 12 for quite some time. The pair of BMs should give me that kind of output with similar sound in a smaller box. Smaller box than the 8s want as well. Got a great concept on how to integrate the BMs into the interior/stealth install. Also gives me better options for amp mounting. The more I think about it the better I like the idea. Hopefully they'll be ready by the time I get home, or soon thereafter. Heck I might even be able to fit a pair of the new Mags in the spot I'm thinging about.

Well yeah, except for those...that's why you use egg crate foam and deflex pads inside your sealed enclosures though...and double up the MDF on all walls with deadener between...and need twisted pair speaker wire...

A sealed enclosure has a shallower roll-off than ported but it usually begins to roll off at a higher frequency. The result is that at really low freqs, the sealed box will have more output. You also can't make the assumption that a ported box is louder than a sealed one. For a given range of freqs it may be louder, but the reference level will be the same for both and once you get to the really low freqs where the sub is just fluttering in the ported box, the sealed box will be louder and actually under control.

Was 113 here today...

To keep the footprint small it would almost have to be a stacked design with the two boards on on top the other with a heatsink all the way around. Basically 2 amps with a shared power/ground terminal back to back (rather than end to end) in a tall heastsink. I think that you guys would be surprised at how well the 5 channel amps sell with the general consumer rather than the hobbiest crowd. You guys have to realize that we represent a TINY percentage of the aftermarket audio consumer base. The majority are more like my wife who want simple and better than stock but aren't willing to go to extremes to get it.

There's a lot more to that unit than a crossover and it's not what you need.

Unless your goal is to be a loud as possible on the meter and you're trying for every last 10th, the shape isn't very important at all. If you're talking a sealed enclosure, the shape doesn't matter either.

Modern fighters don't smoke. Even when lighting up the afterburner. As soon as the first stage of the AB starts dumping fuel into the exhaust, the ignitors have it lit. Even at an air show (unless it is a specific smoke generator like the T-birds and Blue Angels use) there is no smoke on a current gen fighter. The jet cars at the drags smoke because they use old generation engines and you are watching them start the engine at the end of the track. It was most likely an older fighter. The F-4 held the time to climb record for years and it's a smoky bastard.

If you're bending on a circular profile all you have to do is figure the arc length. This is going to be 1/4 of the circumfrence of a circle with the same radius as your bend for a 90 deg bend.

Kenwood Excelon DNX-5120 About $630 shipped on eBay.

Yeah, I was thinking more along the lines of a pair of BMs wired to 1 ohm with the gain dialed WAY down. I don't need a lot of output. If I were to go with Mags, 2 ohms would be the wiring of choice. No reason to wire to 0.5 ohms especially if I'm trying to limit power and electrical drain.

Yep, the old WinISD referenced true Mach. Modern jets don't smoke, makes it too easy for the enemy to spot you. Depending on the time frame you're talking about, they could have been F-4s which smoke like crazy and won't get off the ground with less than full power.