# L7



## scrappy (Jun 30, 2002)

I hyave 2 12 L7 I have been waiting for a couple months to build a box but havent had the time. I have a box that is tuned to high, I decided to see if the subs worked maybe I got bad replacements. I turned my gain just under half way the bass boost off and the low pass filter around 150 or so. It sounded good on my way to work anon the way home it sounded weird out of the right speaker not as loud as before I checked it out today and it sounds kind of scratchy. Could it be one of the voice coils are starting to go bad or was bad from the factory. I only turned the hu up to 16 any help would be appreciated dont want to waste money. Im not to happy with kicker at the moment. Could it blow from a high tuned box so soon. The first set lasted almost a year the second a couple weeks to a month and these ones 1 day? I was going to have a box built but now I dont know


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## sr20dem0n (Mar 19, 2003)

any sub in a high-tuned ported box without a subsonic filter and a high gain like that could definitely blow in a day

it sounds like your voice coil is rubbing, which can be caused by a defect or possibly by overexcursion, either of which are a possibility in your case. You've gone though so many subs, why do you just keep replacing them? Subs don't just blow at random, they blow if there's a problem, you should have realized there was a problem with your install and fixed it before blowing 2 more subs.


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## scrappy (Jun 30, 2002)

I know that there is a problem with the box just needed time or money to get the box I need oh yeah there was a subsonic filter on my amp something preety low though. I just wanted to check if the subs were okay before paying out the ass for a nicely done box at a local shop I just send the subs in so no cost to me. I know seems kind of dumb thats why they sat in the boxes from kicker for 2 months. I couldnt figure out how to fit everything myself so a shop was going to do it. What causes over-excursion. If it is the tuning dont both subs blow? I never had problems with any other subs except kickers are some subs just that much more sensitive. I thought my gain was consevative compared to what the shop I bought the subs at had it again not even half way up very little power flowing through them I thought it would work. One of my friends just got a remnufactured sub and it had problems that is why I tried this out


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## scrappy (Jun 30, 2002)

I went and seen the guy I bought them from and he says he doesnt think that there is anything wrong with the subs and that it sounds a little different but it could be the trunk what do you think. He works somewhere else but went out of business with the other shop. Im maknig an appointment tommorow for a new box and amp rack to be built so I will see if it is the sub or not. How come half way up is high on the gain I always see them at 3/4 or more again thanks for the help sr20 demon


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## sr20dem0n (Mar 19, 2003)

Well at least you have a subsonic, but you don't know where it's set? It's best to set it ~5hz below the tuning frequency.

*What causes over-excursion. If it is the tuning dont both subs blow?*
A bunch of things can cause over excursion, in a ported box, the easiest of which is too much power at a frequency too far below the tuning frequency. Once you get about a half an octave below tuning, the subs behave like they aren't in a box at all, which means that 800+ watts that were perfectly fine around tuning, are now causing the sub to move WAY beyond what its suspension will allow. Yes it will happen to both, but damage doesn't instantly happen as soon as the sub over excurts, it's possible that both of the subs did it but only one was damaged.

*I never had problems with any other subs except kickers are some subs just that much more sensitive.*
yeah different subs will behave differently when they drop below tuning and really start moving, the other subs you tried might have had a very large xmech (how far the cone can move before hitting something hard) and a low xmag (how far the motor can push the cone while still staying linear). In subs like this, you can keep pumping in power and they'll just go into thermal compression before they bottom out and damage things mechanically.

*I went and seen the guy I bought them from and he says he doesnt think that there is anything wrong with the subs and that it sounds a little different but it could be the trunk what do you think.*
could be, it's hard to tell without actually being there. The easiest way to tell is to take the sub out of the box so that it's playing freeair, and then put on a ~50hz test tone (with the volume very low so you don't start bottoming it out) and listen to it play. If you still hear the scratching/knocking then it's probably a rubbing voice coil. If the sound stops, you could have a leak in the box or it could be something rattling in the trunk.

*How come half way up is high on the gain I always see them at 3/4 or more*
it all depends on how powerful the low-level signal that you're feeding the amp with is. The reason you normally see 3/4 or higher gains is because 99% of the people who own amps are ignorant when it comes to that control. They think that that knob is a direct control over how much power the amp puts out, like min gain is min power and max gain is max power, and anywhere in between is "half way up". This isn't how it works at all, and thinking that this is how it works is how people blow amps and subs all the time and keep companies like rockford fosgate and sony in business.

At the end of this thread I posted some info on the gain control, with some links explaining its behavior and how to properly set it:
http://www.nissanforums.com/showthread.php?t=58706&goto=lastpost


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## Zac (Mar 10, 2004)

I can vouch from personal experience, L7s blow easily and are HIGHLY picky about their box...while their loud they arent the loudest.


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## scrappy (Jun 30, 2002)

The subsonic filter is 18hz and its not adjustable. Kicker recommends it to be set at that and the box tuned to 37hz. Wich I beleive the box is. I now know that is wrong but thought I could beleive what they said. Ill check out the free air check tommorow so is that how I should have checked if they were good in the first place. Just got a little scared when my freinds came back messed up. Thanks for the links meant to look at them when reading the other thread but didnt get a chance. Thanks for the explanation of everything Ill let you know how it goes tommorw hopefully well.


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## scrappy (Jun 30, 2002)

NickZac said:


> I can vouch from personal experience, L7s blow easily and are HIGHLY picky about their box...while their loud they arent the loudest.


Definetely very picky about the box. What do you think is the loudest?


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## scrappy (Jun 30, 2002)

Okay I tried what you said and pulled the speaker out turned the gain down and the hu to 6 it still made the crackling. Does that mean it is starting to blow? Is there anything I can do about this? I wonder if it was the box or a defect from the factory Im going to call kicker and see what they say about this thanks for the help


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## Chicago Tony (Apr 15, 2003)

I totally don't agree with this statement. I have been running a single 12 L7 off a DEI 1100 for about 1.5 years. I have been feeding the full 1100 watts into the sub and not 1 sign of problems. IMO Kicker L7's are bulletproof if you treat them right. I have been running Kicker subs for as long as I can remeber. I think its an install issue that Scrappy is having causing him to blow the subs.







NickZac said:


> I can vouch from personal experience, L7s blow easily and are HIGHLY picky about their box...while their loud they arent the loudest.


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## scrappy (Jun 30, 2002)

An install issue how? Car to elaborate on that a little.I dont really know why Im blowing the subs. Im in the process of getting new subs again from kicker and having a shop custom build a box and amp rack for my car. Like I said I never had a problem with other subs before So you guys tell me


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## Chicago Tony (Apr 15, 2003)

I don't know what the problem can be without actually looking at it but you have blown 2 or 3 subs in a short time. IMO that has to be an install problem. Amp, headunit or enclosure there is a problem somewhere. Have the custom made box by built for them and make sure they are in the right amount of space. The 12 L7's can go into a ported enclosure anywhere between 1.75 all the way up to 5 cuft per sub.






scrappy said:


> An install issue how? Car to elaborate on that a little.I dont really know why Im blowing the subs. Im in the process of getting new subs again from kicker and having a shop custom build a box and amp rack for my car. Like I said I never had a problem with other subs before So you guys tell me


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## scrappy (Jun 30, 2002)

Well if you are talking about the enclosure you are right. How could the head unit be the problem or the amp. All anyone was saying is that the L7s are very picky about their box. I am doing a 1.75 cu ft per sub tuned at 33 hz. That should fix my problem I hope What is your box tuned at


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## Chicago Tony (Apr 15, 2003)

My box is 2.5 cf tined to 38hz. It was built to Kickers spec on their website. I don't what your problem can be or whats causing the problem. You said your bass boost was off. How about the actual bass setting on the headunit? Is there a loud button on your radio? Was that on or off? Even though you gain was just under half way that still might have been to much. How loud do you play your system? Right now I am building a box that will be 3.5 cf tuned to 33 hz. That should be nice and low. I have been running Kicker subs for along time and never had any problems with them. IMO they are well built subs and bulletproof. 

To get off the topic somewhat I just seen a video of 4 12 L7s being burped off of 8000 watts. Thats 2000 per sub.







scrappy said:


> Well if you are talking about the enclosure you are right. How could the head unit be the problem or the amp. All anyone was saying is that the L7s are very picky about their box. I am doing a 1.75 cu ft per sub tuned at 33 hz. That should fix my problem I hope What is your box tuned at


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## scrappy (Jun 30, 2002)

Hu bass set at 0. Loud button was on but on my kenwood that seems to only enhance the highs. I have always heard good things about kicker thats why I went with that setup. Right before I blew the first set I was told that the box was tuned to high. Hopefull that is all I will soon find out. I may end up running a sealed box to save room. I think my box is tuned to around 38 or so not really sure it was a pre fab box that the shop sold me


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