helotaxi

If you get the idea of using a 100.4 per door the crossovers on the 100.4 will do all of your frequency division for you. Bridge both pairs of channels on one to run the 8s and then run the other normally with the tweets on one pair of channels and the mids on the other pair. Then you just need an EQ.

Pilot in the USAF. Flew Hueys for 5 years and now spend my days flying RC planes for a living. Granted they're $5 mil RC planes with missiles. "Why do I do it you ask...well the scenery changes, they pay me well and they let me play with explosives."

I'd be there to show support (I don't do SPL) except for 2 things: 1) I don't live in Great Falls anymore and slightly more importantly... 2) I'm in Afghanistan. I think that the biggest limiting factor on turn out is the fact that you're in Montana. Don't get me wrong I love MT, they're just aren't a lot of people there and even fewer that know jack about car stereo. I swear I've been to Sydney, I just don't remember where it is

The general car audio term "high current amp" has nothing to do with the amount of current that the amp draws. It was used back in the day to describe the competition style amps that were stable into low impedances. There are two ways to make power, one is to have high voltage on the outputs into a relatively high impedance, the other is to have fairly low voltage but relatively high current by wiring the amp into a low impedance. The amps designed to make power via the second method were called "high current." The power supplies were overbuilt compared to a similar 2 ohm stable amp with the same 4 ohm power rating. The output devices were oversized and there were typically more of them. The amps didn't have to be all that powerful or draw a lot of current. U.S. Amps made one rated at 12.5W per channel and it was quite small. At full tilt into a 0.5 ohm load the amp only drew on the order of 30A but it was a high current design. PPI made a similarly small high current amp in the ProMOS 12.

Your amp should have a crossover built in. No point in adding a second one. As long as your gain is set correctly, and the amp is making full power with the HU, there is nothing that a line driver will do for you either. Your friend is misinformed.

I won't bother for two reasons 1) its a total mess and 2) it will leave a void in the joint in an already weak medium. Not worth it in MDF. I just do a butt joint with a 45 deg piece on the inside that I brad nail in place while the glue dries. I don't bother with screws in MDF either. Just cover the joint surfaces in glue, tack it in place with a few brads and then clamp the crap out of it and wipe the excess glue off the outside and run a bead of glue on the inside to make sure I have a good seal. With straight cuts I've never had a problem with sealing or with needing screws to pull a joint together. I've also never had a joint fail but I don't do SPL rigs so my requirements are a bit less.

Ordered 2; debating on whether or not to order the 3rd... edit: just ordered the 3rd. Gotta have the amps available if I decide to go 3-way up front...

Gotcha. Fair enough.

Big fan of biscuit joints myself, but that's mostly in birch ply. I've snapped a handful of screws in the past though none of them were in end grain.

The 100.4 cannot bandpass. Your options are either high pass, low pass or full range (choose one) on each channel pair.

Why the 8v preouts? It really doesn't make a difference. As far as a processor, what do you want it to do? Crossover? Crossover and EQ? Crossover, EQ and time alignment? The preouts on the HU will make no difference at all once you add the processor after it in the signal chain and even the processor preout voltage isn't very important. 2V is plenty for any amp worth having to make full output with zero noise. If all you're looking for is a crossover, the 100.4 has pretty much everyting that you need built in. Bridge one to run the 8s. Run the other normally to the mids and highs. The only thing that you'll need is a basic 2-way crossover to low pass the 8s (the amp will do the high pass) and high pass the mid-highs (the amp will do the division between the mids and tweets). You can pick up a basic Coustic crossover that is up to the task for $50 shipped NIB off eBay.

And is also wrong...the amp clips sooner, but that is not DC...close but not DC

No one has heard the difference a cap has made. A bigger/better battery will make more of a difference in the electrical system than any cap of any available size will. A cap has less than 0.5 amp*seconds per Farad of usable storage capacity compared to the 7 amp hours for even the compact Hawker/BatCap 800s. If your electrical system is so overtaxed that you're worried about the alternator giving out prematurely, you need to be looking for a bigger alt. At that point a cap is like putting a band-aid on an arterial bleed. One of those little butterfly band-aids at that. All the things that the marketeers claim that a cap does for a system are better handled by a battery or batteries. There are caps in your amps, yes. However, don't you think that if more capacitance was needed to make an amp sound good, the amp manufacturer would have included that in the design? There is one legit use (and even it is a little on the "snake oil" side of things) for a cap, and that is as a noise filter. Higher current alts tend to have a bit more ripple and those set to higher voltage have even more. A cap can filter out the ripple, though the power supply capacitance in the amp itself is usually more than up to the task of taking care of what the battery leaves.

Care to explain that? The amps always draw DC current. That's what the batteries and alternator put out is DC power.

whats everyone think about this? i mean with this its one positive thing about keeping the cap, until i get my engine swap and get a h/o alternator but that wont be until like 2 years or something. I think that's the job of the battery, not a cap.

Unless the sub is in the same position with the same volume displaced by the enclosure and with a PORT in the same place as your comp enclosure, you're still missing a lot. You've got the right ideas, they're just imcomplete in their application.

CDT M6...wipe up the drool...

They say that because some of the guys at CA&E are morons. I gues it's also possible that in certain enclosures and depending on the Qes of the sub, it could actually show the amp a 1.5 ohm load wired in parallel. Seriously doubt it, but it's possible.

He's not. He, like a lot of us, doesn't care about SPL . He does understand acoustics though and knows that what you're doing, while better than totally uneducated trial and error, is still far from the total picture. Taking measurements with a tape measure doesn't give you the peak frequency of the vehicle. It might give you an idea where you can create a standing wave, but it won't account for the rest of the interactions that occur and that can have an even larger influence on the total SPL potnetial of the system.

Call it a gift, call it a curse. I remember random crap for YEARS. Useful stuff like people's names...nope.

The SS "Class A" amps were actually fairly efficient as they approached full power. They were not Class A amps, but were rather fairly high-biased Class A/B amps with a Class A input stage. What they were was amazingly quiet (CSR measured s/n of 90dB ref 1 watt IIRC and that was just on one of the Reference line, not the Class A line which used tighter tolerance components.).

Efficiency isn't the real problem. The problem is that the amp is going to try to make 2x the power when you half the load. Even with 100% efficiency for both loads the amp will have to draw 2x the current to make 2x the power. If you can't give it that amount of current without the voltage dropping significantly, you will have issues.

If the amp is running into a designed load (i.e. it's made to run at 1 ohm--the Orion 2500D was not made to run @ 0.5 ohms) then it shouldn't tax the electrical system appreciably more than an amp doing the same power at a higher impedance. There are some exceptions to this but they are just that, exceptions. Something to consider is that an amp that will do the power that you're looking for at 4 ohms is going to 1) cost more that one that does it @ 1 ohm and 2) will probably be a bridged Class A/B amp which will be less efficient than a Class D and actually place a considerably larger strain on the electrical. The issue with the 2500D (and other unregulated amps) is that you have to be careful to keep the voltage from dropping too much with the gains set very high. The dropping voltage allows the rail voltage to drop and gets the amp into premature clipping. The result is exceeding the duty cycle of the output FETs and smoking them. Running the amp at 0.5 ohms isn't the sole cause, you could do the same thing running it into 4 ohms, it's just that the amp draws a tremendous amount of current when run into 0.5 and it takes a really big current reserve to keep the voltage from dropping to dangerous levels.

I've noticed that a lot of morons buy JL thinking that they are loud and are disappointed when they are not. Part of this misconception stems from the reputation of JL for making a great product and morons associating only "LOUD" with great sub. The other part is the shops that carry JL are staffed with morons who push JL as the answer for every subwoofer need. People who see SPL as the only merit of performance for a sub are always the first ones jumping on JL for being "overpriced" or "crap" or the such. On the SQ side, I don't think that I've really heard much ever in the way of negatives about JL subs from people who use their systems to listen to actual music at sane levels. Most use the W7 and W6v2 as their standard of reference when talking about other subs. Must be that wet fart sound that emmulates the bottom registers of the cello so well. Most of the folks out to create a realistic sound in their car like JL or say something to the effect of "I couldn't afford the W6 that I wanted and settled for X instead, it sounds almost as good." My take on the original question posed, and I by no means have used a lot of different brands of equipment...I haven't seen much in the way of innovation on the SQ front from anyone but JL in a very long time on the mainstream side of things. The W7 was a quantum leap and the W6v2 reaped some of the design benefits of that leap. Pretty much all of the other mainstream players have gone the route of focusing on SPL either in a "bang for the buck" loud budget sub for the daily beater who wants attention or the balls to the wall powersink for the SPL competitor. They seem to be of the opinion that if you aren't after loud then we don't care. I can kind of see where they're coming from since the majority of the idiot kids out there just want some loud subs they cater to the mass of the market. That leaves those of us wanting quality over quantity looking for niche products and audio is no different from other products in that you find your niche products on-line. Since most of the online brands are smallish operations they can focus on the SQ customer, if that is the niche they choose, and build a product that doesn't have to have mass appeal to be considered successful from a sales perspective. I've been using JL subs for a LONG time. I got my first for Christmas in '91. That was the first year of the original W1 series. It was a great sub back then and it's still a very good sub from an SQ POV. I still have it and it still works as new and looks almost mint. I ran the crap out of 6 of the original 10w6s for the better part of a year before the vehicle they were installed in died in a rather nasty wreck. Two of those became the first subs I ever killed when the sub amp came loose in the wreck and punched holes in the cones. I sent 3 of them in for recone after the surrounds rotted out during nearly 6 years in storage and I still have them, too. I made the jump to online brand subs about 4 years ago when I bought a XXX. I will probably never part with that sub. It's heavy and the ported boxes I've used it in took up the whole of my trunk and weighed a TON but I was never disappointed with the sound of that sub. I also have a quartet of the original version of the Ascendant Audio Assassin 8s. I've used two of them and I was very please with the sound of them and I know that it would have been impossible to top their performance for the price (try finding a mainstream sub for $45 with full warranty).

Glad you figured out the problem.