l7 15’s in a silverado
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=16791
Printed Date: May 15, 2024 at 4:24 AM
Topic: l7 15’s in a silverado
Posted By: doubleduece
Subject: l7 15’s in a silverado
Date Posted: July 28, 2003 at 2:49 PM
I have a 1997 extended cab silverado. i was originally planning on putting 2 kicker l7 15's in it, each powered by a kx 1200.1 kicker amp. i was wondering if i could fit three in there with enough air space and how many amps would i have to use? i dont really want to wall it off unless that is my omly option. should i dynamat my truck? im kinda on a budget,like my bro, l7sdime, and someone told him to use brown bread,wut is that?? How would i go about installing this system? Thanx 4 your help. Trey
Replies:
Posted By: wrencher_25
Date Posted: July 28, 2003 at 6:46 PM
Brown Bread is another form of dynamat. It's always a good idea to use Brown Bread or Dynamat ESPECIALLY when doing a system like you are planning to do. It helps keep bass in and you lose less sound due to the rattling of your truck. As soon as your truck starts rattling, it takes away from pressure that COULD be building up inside your vehicle.  Good luck fitting three in...no clue with that one, u'd have to work out some box sizes and how many cubic feet you'll have without having to build a wall. Good Luck ------------- Andrew Weitzel
MECP First Class Installer
Posted By: l7sdime
Date Posted: July 29, 2003 at 10:42 AM
thanx for replyin 2 me,im gonna need some help with this stuff. well i know that one of the l7 15's needs 6.0 cu ft. so for all three of them i will need around 18 cu ft. and do you have any advice on amps? i was planning on running a kx 1200.1 to each of them,but that would be mega expensive. My bro wants to get 4 l7 12's, and he was told to run one kx 1200.1 to them in a series,and all of them would get 1200 watts a piece. should i do that or should i go with two amps to get closer to max power,and then run those 2 amps in a series? Thanx alot for the help. Trey
Posted By: doubleduece
Date Posted: July 29, 2003 at 10:53 AM
i jus wanted 2 say that i was accidentally on my bros name (l7sdime) when i replied to u in the first place. srry bout that. Trey
Posted By: donkason
Date Posted: July 29, 2003 at 2:36 PM
You don't need one amp per speaker. This was a misconception of mine when I first started car audio. What kind of voice coils are your speakers dual 4 or dual 2 ohm. And I told your brother he needs to wire his speakers in a series and then parallel to the amp. I am trying to find a diagram because explaining it is somewhat difficult. You can run many speakers on one amp as long as you the impeadence (ohms) of your speakers match your amp.
Posted By: doubleduece
Date Posted: July 29, 2003 at 4:42 PM
ok,thanx alot for replyin back to me. i saw that u helped my bro out alot and i was hopin 2 hear from you. if you get that diagram could you please send it to me? Is there any othr advice you could giv me on how to do my systme? thanx alot again. Trey
Posted By: donkason
Date Posted: July 29, 2003 at 5:20 PM
first I neen to know if your speakers are dual 4 ohm or dual 2 ohm voice coils. Otherwise I can't really help you. You don't exactly need 6 cubes for each sub either. If you want to do a ported enclosure you can use the minimum size is 3 cubic ft. and the max is 6. So if you don't want to built a wall you can shrink your box some. I wouldn't suggest 3 cubic ft. though if you are going for spl but you do have some room to play with from 6 cubic ft. I wouldn't want to wall it off either. It is too much of a hastle. You also need to make sure you built your box right. There is a lot more to it than slapping wood toghther. Are you going to have your box built by a professional? If not I have some pointers and the 12 volt has some great resources for info on ports
Posted By: tdsteele
Date Posted: July 29, 2003 at 5:31 PM
he was told to run one kx 1200.1 to them in a series,and all of them would get 1200 watts a piece. That statement is not right. If you run 4 subs off that one amp they would each get a share of the 1200 watts, so each would see 300 watts, as long as the ohms were right anyways. As far as wiring diagrams goes, i think the Rockford site has the best thing for getting good diagrams https://www.rockfordfosgate.com/rftech/wiringwizard/. Just put in what you want or have and it will give the options you can choose from to wire the subs for the impendance the amp will see.
Posted By: doubleduece
Date Posted: July 29, 2003 at 6:47 PM
Donkaston,thanx for the help once again. I was planning on b uying the 4 ohm version,is that ok? So if i port my box then i would be able to make it smaller? Why wouldnt you use just 3 ft? wut wuld be about the right amount? I was planning on buildin the box myself,i like doin stuff myself,it helps me learn better. How would you go about building it? And ill be more than happy to hear those pointers. And wut about what tdsteele said,is he talkin about antoher way to do it? Thanx alot. Trey
Posted By: aggie altima
Date Posted: July 29, 2003 at 7:33 PM
Yeah, i was wondering about that statement as well.
i read what he told your brother to do. wire the terminals of each dual 4 ohm voice coil sub in series to make each sub 8 ohms, and then wire each sub in parallel to provide a 2 ohm load to the amp. this is correct.
but when you wire resistors in parallel, the current is divided among the resistors. say you wanted to find the current to each sub. lets call the current provided by the amp, i_amp. using the current division equation, the math involved is
[(8|
|8|
|8) / (8|
|8|
|8 + 8)] * i_amp
(8|
|8 means 8 parallel to 8, as in the resistors)
this reduces to
[(4|
|8) / (4|
|8 + 8)] * i_amp
which will reduce to
[(8/3) / (8/3 + 8)] * i_amp
and the final result is
(1/4) * i_amp
this means that each of the 4 speakers, each having an 8 ohm resistance, will recieve 1/4 of the current coming out of the amp, which leads to each of the speakers getting 1/4 of the power.
basically, the mono-amp only knows that it has a positive and negative speaker terminal, not the number of speakers. it only cares about what resistance you are providing at those terminals, and it provides power to the single final resistor which it sees.
if anybody objects to my math, please let me know, so i may be corrected.
-------------
Jon
Don't like rockford subs? Then don't look at my car =)
Posted By: tdsteele
Date Posted: July 29, 2003 at 7:54 PM
Ok im totally lost now, maybe i said the wrong thing. So are you saying the 4 subs would see 1200 watts each or 300 watts each?? Just going by what i have always heard and what seemed like common sense. Would like to hear some other opinions on this one.
Posted By: l7sdime
Date Posted: July 29, 2003 at 7:59 PM
this is doubleduece's bro. yeh im wonderin the same thing baout my 4 L7 12's. if i wire them in a series with 1 kx1200.1 will they see 1200 or 300 a piece. im with tdsteele im completely lost any more suggestionsa will help me and my bro thanks. wes
Posted By: doubleduece
Date Posted: July 29, 2003 at 8:16 PM
ok,i guess ill join the group, im so lost. someone help mr out,lol. trey
Posted By: tdsteele
Date Posted: July 29, 2003 at 8:37 PM
Well, my opinion, what ive always seen and heard from local installers and all the installs you ever see, whether it be right or wrong, which we are trying to figure out, is if you have a sub that can hold 500 watts, you try to get an amp that puts out 500 watts, if you 2 or 3 or 4 of those 500 watt subs, you get an amp that adds up to the power they require, so 4 subs would be 2000 watts, you get 2000 watts of power. Makes sense right?? But, on another note, i can see where he is saying that the amp is only seeing the load presented to it and not the number of subs, case in point, local shop that did my install has a room with 64, yes 64 12" subs in it, all run off one 1200 watt amp. Now, if the way im thinking and the guys at that store say is right, those subs are getting 18.75 watts each, not alot huh and probably wouldnt move them that much, right? Well those subs pounded like they were getting hundreds of watts each. So, kinda gives you some more to mess with your head. I would love to know whats right and wrong on this one cause if the subs are all getting the max power then why do people have multiple amp systems??? Is everyone wrong in the way we think??
Posted By: donkason
Date Posted: July 29, 2003 at 10:00 PM
About your box. I may not have described it clearly. A ported box needs to be bigger than a sealed. Kikcer reccomends that you have a box from 3 to 6 cubic ft. I am trying to say that if you can't fit a 18-24 cubic ft. box in your truck you could make it as small as 3 cubic ft. per sub. I do not suggest a 3 cubic ft. enclosure for massive spl. Normally the bigger the better so it does not have to be 6 c.ft. but as close as you can make it to that the better off you will be. With a box that big you will have to brace the hell out of it and the 12 volt has a port calculator so you can tune your subs the the ideal frequency. All you have to do is punch in the port diameter and what frequency you want and it will give you the port length. Also make sure you use 1 inch medium density fiber board or high density, also use lots of glue when assembling for extra strength. When you are done seal all of the joints with some silicon caulking and a caulking gun to make it air tight. There are many more things that would help but I can't think of them. By bracing I mean internally putting braces in the box. There are lots of tutorials on the net for heavy weight box building that will help more than me. www.soundstream.com has one. I put up a post on the whole ohms watts issue. Hopefully we can get that resolved soon. I might be wrong. If so I do apologize. As much as I think I know I still learn everday
Posted By: aggie altima
Date Posted: July 29, 2003 at 10:04 PM
well, i thought i read somewhere that increasing cone area (i.e. adding more subs) can lead to more bass, but i would think that increasing the power AND the number of subs would be easier for the amateur installers, who don't have access to that many subs or the skills to build a perfect ported enclosure. i myself wouldn't be able to build a perfect enclosure, so i'd stick to adding more power  . well, that's just what i think. ------------- Jon Don't like rockford subs? Then don't look at my car =)
Posted By: aggie altima
Date Posted: July 29, 2003 at 10:06 PM
oh yeah, if anyone was confused by my entry about current division, i was trying to prove that the subs would each see (1/4) of the power delivered by the amp, which means 300 watts a piece.
-------------
Jon
Don't like rockford subs? Then don't look at my car =)
Posted By: donkason
Date Posted: July 29, 2003 at 10:21 PM
Personally I would rather do less subs in the right box than more in a poorly built box. In the long run it really is worth it even if you have a professional shop built one for you. I can't stand cutting up wood so I do everything else myself but the box. Espically if you are doing competition you don't want to have a system that will put you in a big boys class by many subs and amps but it can't live up to its reputation because the box is making everything distort at moderate volumes. Sounds like aggie altima is right about the 300 watts per speaker. So I guess I would buy 2 amps for 4 subs and get dual 2 ohm subs wire the v.c.'s in a series and the subs in parallel. This should give you a 2 ohm load per amp and 600 watts per sub. I stand corrected.
Posted By: bberman1
Date Posted: July 29, 2003 at 10:31 PM
With a 2 ohm load on the amp you will get 600 watts total and 300 watts per sub. Now each sub is rated at 1000 watts rms. You will want to get (3) Kicker KX1200.1 and (3) dual 2 ohm L715’s. Each sub should be run off its own amp wired in parallel (1 ohm) for 1200 watts per sub. As far as the enclosure goes do you realize how big 18 cu/ft is? Do you plan on driving this thing?
Posted By: tdsteele
Date Posted: July 30, 2003 at 12:56 AM
l7sdime and doubleduece, be sure to check out this other post that was started off of this one, good info for you two. https://www.the12volt.com/installbay/forum_posts.asp?tid=16856&PN=1
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