Kicker L7 12's . Left over from my tahoe..Can I use these?

3884 Views 8 Replies 4 Participants Last post by Eric Mathews, Jan 13, 2008

Discussion Starter · Jan 4, 2008 (Edited)

I have a finished recroom in my basement that is 22x17 with a 7' insulated drop ceiling and wood floor. I read posts here for a few hours about different powered subs and dont really have the cash to buy multiple powered subs that are going to run over 1k. I have 2 new Kicker L7 (square type) 12'' subs that were going into my old tahoe before I wrecked it. The subs are dual coil and the coils are 2 ohm. As of right now, I only have my 73'' mitsubishi dlp tv and am shopping home theater components. I have built alot of sub enclosures in the past 10 years. Optimal sealed space for these are 2cuft sealed for maximum spl in a car, but what about in a large room. I was thinking I could run both subs coils in series for a total 8 ohm load, but would need to 1000k watts rms minimum to get 250 @ each coil to even move these subs. Should I mess with the whole power converter thing and just run a signal off a lower powered reciever. Would it be cost effective? Or should I just spend the money on a decent home reciever and run them off that? Any suggestions? Also, how do you think the subs would react in a 2 cuft sealed enclosure in such a large room with the low ceiling.

Heres a pdf file on the specs from Kicker.com mine is the L7 12:

http://www.kicker.com/06/tech-support/manuals/manuals/2006/2006 L7 Sub b01 WEB.pdf

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Mike P.

· #2 · Jan 4, 2008

The PDF file you linked to does not have the T/S parameters. However, in the WinISD database, there are 3 - L7 12 inch subs listed, and I'm assuming yours to be the S12L7 from 2002. With a Fs of 31.2hz and Xmax of 12.7mm, the best you could do with them for HT would be 8 cubic feet ported tuned to 20hz.(each) Maximum excursion would be reached at 30hz and 18hz with 250 watts. SPL would be a respectable 110db down to 18hz, and add room gain on top of that. 2 cubic feet sealed for HT is not even a consideration with these subs. I suggest you download WinISD and do some modelling so you can see what it's all about. I would suggest using a plate amp to power these subs, as most plate amps has a subsonic filter built in, which these subs will need to protect them from frequencies under 18hz.

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Discussion Starter · #3 · Jan 4, 2008

Ok, I have read what you typed, but I really dont understand the dynamics of a big room. I do understand it in a car though. Is such a large enclosure needed to get the Hz down to where I would need it for tracks in a movie so to speak or because the room is so large? I have looked at using a rack style amp on parts express that was 300.00 and will support a 4 or 8 ohm load and at 4 ohms will put out just over 1000 watts rms. One other question for now, does the box need to be tuned so low at 20 hz. I have access to a slot ported box that the subs share a common area and it tuned at 38hz and the box is about 6 cubic feet. Or do I need the 8 feet to compensate for the room? You did mean 8 feet total for both, right?

Richard

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ccdoggy

· #4 · Jan 4, 2008

The problem with tuning that high, as some do in cars, is that many times they are trying to just get more SPL out of the driver, and tuning higer like that typically causes a hump in spl output at the tuned freq.

In theaters the point is to make the sub have as flat a response as possible with even output through out the range. The box size and tuning have nothing to do with the room, it has all to do with the freq response of the driver.

You could use that box, but alas i would expect it to get really loud and messy around 38hz and after that get next to nothing for output below say 48hz.

If you have access tot he box give it a try and see if you like it. Maybe you will like it, maybe not. worth a try.

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Rodny Alvarez

· #5 · Jan 5, 2008

You need to check out the Behringer EP 2500 for those subs, 1500 watts @ 8ohm!!!

$289.96 @ amazon.......Amazon.com: BEHRINGER EP2500 EUROPOWER POWER AMP 2 x 1200W: Musical Instruments

With the EQ BFD $389.95.

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Discussion Starter · #6 · Jan 5, 2008

Any other inputs as far as HT size enclosure. Anyone want to trade or no anyone who wants to????

Rich:yay::yay::yay::yay::yay::yay::yay::yay::yay::jump::jump::jump::jump:

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Mike P.

· #7 · Jan 5, 2008

bosco2023 said:
Ok, I have read what you typed, but I really dont understand the dynamics of a big room. I do understand it in a car though. Is such a large enclosure needed to get the Hz down to where I would need it for tracks in a movie so to speak or because the room is so large? I have looked at using a rack style amp on parts express that was 300.00 and will support a 4 or 8 ohm load and at 4 ohms will put out just over 1000 watts rms. One other question for now, does the box need to be tuned so low at 20 hz. I have access to a slot ported box that the subs share a common area and it tuned at 38hz and the box is about 6 cubic feet. Or do I need the 8 feet to compensate for the room? You did mean 8 feet total for both, right?

Richard

The parameters of the sub determine how large the enclosure should be to get the most low end extension. There is lots of low frequency information on todays DVDs, tuning a sub as low as 20hz in this case allows you to get the most out of this specific subwoofer. The 8 cubic foot size is for each sub, not both together. If you are willing to make compromises, you can have a smaller box that is tuned higher, at the expense of low frequency output. I strongly suggest you try out WinISD and see for yourself how changing box size or tuning frequency affects the output of a subwoofer.

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erh7771

· #8 · Jan 5, 2008

I too am from a car audio sound back ground (DB Drags) and IMHO I can live with the peaks from a smaller box or eq them out a bit and eq in lower freqs. Most of the subs in Car Audio have to play dual rolls and give good hit (or transient response) and go low and loud and because of space have smaller boxes where cabin gain (I forget the technical name) make up some of the 30 and below. If you get good low freqs like an kicker l series can give it's usually undefined but usually you're not listening to "defined" music anyway with such subs.

In Home theater fronts and other mid size drivers take care of hit leaving slam (or infrasonics) mostly to subs only unless you're willing to pay.

I took my bahn aw1200 from long ago (yeap, lucked out and got a good 1) in a 2-2.5 cube box with poorly made port and hooked it up to a 2 ohm stable house amp at around 200 watts and couldn't believe how low it got in a open space 37x28 room. Of course it peaked at around 40ish hz but the 30 and below was there and loud and muddy...how I like it

...again hit was taken care of by two 8s.

I'm far from an audiophile and don't mind the peaks (again, I'll eq them out) and most of the bass tracks (unless it's DJ Magic Mike or southern crunk etc) are from 30hz and up any way. Basically if you like car bass you can live with the imperfections the box designs will give for HT.

Also the ep2500 is 279.00 on musicfriend.com and gives out 2500 watts at 4 ohm bridged or 1200 2 ohm single channel.

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Discussion Starter · #9 · Jan 13, 2008

I agree with ehr7771, its a little different in the car scene. You are pretty much only listening to music in your car right? and most of it is 30hz and up. In movies you have the explosions and guns and all that great sounding stuff that actually plays lower then 20hz. You may not hear it, but you FEEL it and thats what you want to do. if you want to play those its easier to port the box and tune it to the frequency that your sub looses its spl so you can gain some more. as for the power inverter, i have done that in the past with good results but i still like to use home theater amp or pro amps. But you will need a big box to get that low. With winisd you can input the different internal volumes and port tuning and and see it change the frequency response right after, its not a very complicated program.

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