jl amp Question.
 

just wondering if the jl 250/1 mono amp would run a pair of 8" w3's sealed just for mid base say from 80hz and up.
thanks
john:chimp:

john
you can call JL Audio tech support they are great. I think the guy's name is Joel (might be wrong on that).. Generally it is the same guy that answers.. I have called him once a week for the last few weeks setting up my system.

what is the impedance on the subs? 4 ohms? I think they also come in 8 ohms? if i remember correctly the 250/1 runs from 3 to 8 ohms? you will need to wire in either series or parralel to stay in the proper ohm range.

they also have a facebook page with tech answers.. try their as well..

thanks,
this is actually for a buddys boat however the subs are 4ohm and the amp can be run 2 ohm safe. the subs are rated a 250 to 500 watts. if they were the main source for base rather than mid base i would be looking at a larger amp for him however given they are more for just mid base i thought he could get away with the 250/1.
thanks for your input.
john

John-
If you do that you will loose stereo seperation, which you don't want to do... I wouldn't do it. If you have a song that goes from right to left those speakers will keep playing in mono. Anything below 80 Hz is non directional anything above is directional. Keep that amp for the 12" sub. Get something else for those speakers. But thats just my opinion. I'm curious what JL will tell you.

not sure i understand completely on that one. a one channel mono amp for two 8" mid base subs that are the jl 8" w3's. what other mono amp would be good for these? just happen to talk to the jl rep and a guy from the factory the other day at extreme car adio. this question didn't really come about til after the conversation however he did mention the 8" subs for mid base would be fine for 80hz and on up. they would roll off anything much over 250hz on their own.


also empty some of your PM's if you can.

Mono amps should only be used for low Hz. Anything above 80hz should be wired in stereo. Wiring the midbases in mono will lower your percieved sound quality. Some some songs may are recorded so the guitar or voice is on the right and the sax or what ever is on the left. So the lower frequencys of the insturment will be coming from both but the rest of the frequency will be only out of one side. It will sound wierd! You've got and are getting good stuff. I would sell the mono amp and get a stereo amp for those speakers as well as the others. Only mono the sub..

gotcha,
i got involved in another project also down state. so i have two going on now.
thanks
john

ps so those two rear side eights you and i were talking about should be a full range amp. i don't know why i was thinking a mono amp for the mid base.

don't you lose volume depth and clarity when you get out of phase too???

Don't think the 250/1 is enough for 3 W3's.... At least a 500/1 at minimum.

And if you're not gonna use the low pass crossover, you should at least bandpass them.... That's using the high and low pass, to play only the frequencies inbetween.

For what John is trying to do that won't work. These are being used as Midbass and x-over at 80 hz and rolling off at 250hz. I like bandpass boxes but there big, heavy and not really ment for this type of application.

I'd suggests sealed box, then put around 150 watts to each of them. The w3's are not very effecient so their gonna like power. Then for your mids get another amp rated at 50-75 watts run it at two ohms for a total of 200-250 watts. This will give you 400 watts above 80hz and 500 watts below 80hz. The specs on your JL j2 1000 amp are 400 watts at 4 ohms, 700 watts @ 2 ohms and 1000 watts @ 1 ohms. Your W6 12 has dual 6 ohm voice coils. This will give a 3 ohm load and give you about 500 watts to the subs.

Also, I think I would stick with just 4 4 ohm mids. If you go with 8 your ohm load is going to be at either 4 ohms total or 1 ohm total. I think one set in the front and one in the back with the propper power will sound great.

Just remember there is no free lunch. 900 watts is going to want power. Your going to have to beef up the alt and probably add at least another battery. My 700 watt Orion set up would make my alt needle bounce when I had it cranked. I have a 65 amp alt. Now I'm upgrading to a 110 amp.

You have no clue at what I'm talking about.... I didn't say "bandpass box", I said bandpass crossover. That means setting a low pass at 250hz, and a high-pass at 80hz. You can't just high-pass a sub and expect it to "roll off". That sounds like TOTAL ****!

LOL. JL Audio told him to let it roll naturally. They said it would do so at that range (250 hz). So I guess you should take it up with them and read getrdunn's post. You seem pretty angry man, go have a beer! You didn't say bandpass x-over, you just said bandpass! So be more specific otherwise don't get pissed if someone didn't read your mind and takes it some other way. Come on man, chill out, and lets help John have a killer stereo!

I couldn't have been any more specific.

Let if roll off? That's a joke.... I'll tell you that I've heard a sub try to play like that and it was awful..

I see you still haven't had that beer! JL AUDIO told him to let it roll off! In a personal conversation John and I had, we both agreed that he need to limit the lows and highs on the mid bass and then run a sererate amp to the mids. Further more if you've read any of the posts, these are being run as MID-BASS not SUBs. I agree you cannot roll of a sub, it will sound like crap! The difference between 60hz and 80 hz can be huge with subs!

That's funny, it is Saturday night though. I think it is about that time. Jony what the JL rep said was for the mids as in the two 8"w3's to roll off assuming they saw nothing below 80 hz. Hell I have no idea. I had even mentioned to him that idealy they would play at around 80 hz to 180 hz or so. Both the JL rep, Bill Barron and the guy from the factory had mentioned that about them naturally rolling off. Personally I thought if it was a stereo amp/full range they would have to be stopped at some point. Even thought they are used for mid base I would think they would produce highs. Not cool the ear either. Didn't really make total sense to me either however just what they said. Are there any amps that would be able to play "from and to" or do they just allow a starting xover point? Other thought was would need an electronic xover. I was thinking originally these should be mono however I was wrong there also. I am trying to help a friend out with his project as well. Also need to get the xs650's.

It was kind of funny actually the other day when I went to GR to take a tour of my old friend Pablo's new shop. Extreme Motoring. He started out as a radio installer many years ago and wound up with his own totally pimped out shop. I'm very happy for the guy. It was at the time I was there talking to him Bill Barron and the Factory guy walked in. Bill Barron use to rep for Kenwood back in the day when I was managing Remes Auto Parts. I was surprised he was still in car audio.

I use to use a really cool user friendly 3 way xover that was completely adjustable with dials. I can't remember the name of it though. Any ideas of a good one. Seems like the name was audiovox or something similar.

OK I had my first beer. :ernaehrung004:

So from what I am understanding then is that a set of 8" subs being used for mid base should only start and stop (2 xover points) at desired signal or hz along with a full range amp???

It's kind of hard to explain... The best thing I can recommend over the internet is just to low pass the 8's. Just because they're lowpassed, doesn't mean they won't have the midbass you want. I've got 2 DD 8's in my CTS-V that play around 125 hz and down, and it's amazing....

http://jonyb.webs.com/photos/04-Cadi...V/DSC_8176.JPG

John-
I was digging into the JL amps manuals and it looks like they have built in x-overs with outputs that pass the x-over signal up to the next amp. From what I can see you won't need a x-over as there built into your amps. Now you just need to figure out what size amps you need!

so with a DV 12" woofer running under 80 hz is it even necessary to run the two 8" as mid base from 80 hz up to 180 - 200 hz? Or would it just be recommended to run them say 125 hz and down with a mono amp? Hope this makes sense.

I guess what I am wondering is what would sound the best provided you have the six to eitht 6.5" for the highs.

gotta run those puppys in stereo.

speaking of puppies why don't you find someone in need of a german shepherd pup. i have 3 left. i will give one away for who ever acts quickly. they are beautiful and have championship blood lines however just not much of a market right now. plus they are going on 6 mo. old. 3 males left. they are getting big.

Instead of spending money on 2 8's, building boxes (they're worthless without enclosures), an amp, and wiring, use that money on more power for the coax's and subs.

The amp you use depends on what woofer it is. Dual 2 ohm? Dual 4 ohm? Dual 8 ohm? Just 1 speaker?

I don't know what you've been told, but mono class D amps are for woofers. Yes, another amp on the coax's. Don't try to use a 2-channel to power a sub and coax's, or even a 4-channel amp if you want it to sound like anything.

Sub amp: sub
4-channel amp: coax's.

BUT, something to keep in mind is that if you use the XS-650's, you'll need an amp that's stable enough to do that. Each 650 is 3.6 - 3.7 ohm, so when you wire 2 in parrallel, it drops the impedance below 2 ohm on each channel and most amps aren't stable with that kind of load. The Syn4 will do it, but not many other amps will. I don't know if the JL's will or not.

I am running a mono sub amp for the 12" w6.

The 8"w3's will be in sealed boxes and on their own amp.

The high will also have their own 4 channel amp. Will power accordingly. The syn4 looks like the ticket especially since the 650's are actually less 4 ohm.

What would be a good amp to run the two 8" sealed?

Again, with running the two 8" along with the 12", what would be more beneficial - to run them as subs up to say 125 or 150hz with a sub amp. OR run them as mids and run the from say around 80 hz up to say 180 hz?

Regardless they will be sealed just wondering what way they would benefit the system.

The Syn1 or Syn2 would be good for the 8's, and I'd have them low-passed around 150hz, but the box should actually be built with that in mind.

not a boat, bu in a old ranger i had, I used 1=12" 80 hz down 500 watts and two 8s, 250 watts apiece 60-200 hz or so, dont remember the settings but I used an MTX active crossover with hz, slope and freq boost. bass was insane.popped the back window out once and my hearing is permanently damaged. all sealed enclosures built to spec on the speakers. The enclosures and a good active crossover network will make a huge difference.

At least with computers you need not hear. LOL... My ears are toast also. To many headers and expansion chambers.

I would say the other is a compliment... I've had some good base but never cooked a rear window. That's actually something to go down in you book of proud things.

Basically the same set up I am hoping to achieve. Rather than breaking in the rear window that I don'w have I just need to over power the twin BBC with CMI / dry pipes.

Either way I don't really plan on making very many friends.