blowing my subs
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=74550
Printed Date: May 02, 2024 at 11:35 PM
Topic: blowing my subs
Posted By: the_one369
Subject: blowing my subs
Date Posted: March 15, 2006 at 9:29 PM
i have 2 12'' Alpine type R's and i keep blowing them. i am pushing each sub with a Kenwood KAC7201 at 4 ohms and the subs handle 500 rms and the amps put out about 470 rms what am i doing wrong??
Replies:
Posted By: DYohn
Date Posted: March 15, 2006 at 9:45 PM
How is your gain set? ------------- Support the12volt.com
Posted By: the_one369
Date Posted: March 15, 2006 at 10:37 PM
not quite all the way up but just below where they start to clip
Posted By: lightdir
Date Posted: March 15, 2006 at 11:27 PM
what is the crossover frequency set at?
Posted By: dragon51
Date Posted: March 16, 2006 at 5:39 AM
The box size and type could also come into play
Posted By: Francious70
Date Posted: March 16, 2006 at 10:03 AM
Need more information like box size, type, bass boost?, crossovers, type of wiring, ect..
Posted By: kfr01
Date Posted: March 16, 2006 at 10:42 AM
the_one369 wrote:
i have 2 12'' Alpine type R's and i keep blowing them. i am pushing each sub with a Kenwood KAC7201 at 4 ohms and the subs handle 500 rms and the amps put out about 470 rms what am i doing wrong??
You are: 1) Clipping your amplifier badly, sending more than 500w to them, and not moving the driver enough for it to cool properly. or 2) Using a ported enclosure, not clipping your amplifier, but just hitting your sub's mechanical excursion limits... or 3) Both. Read https://www.bcae1.com/ for information on gain setting. Like another poster said, we need more information to help you. Are you using a ported enclosure? ------------- New Project: 2003 Pathfinder
Posted By: the_one369
Date Posted: March 16, 2006 at 12:51 PM
the power supply running to the amps is fine i have a volt meter and it is steady at 14.7-8 even when at a stop. the box size is 1.25 cubic feet sealed which is the recommondation for the subs. the bass boost is off. the frequency is set to about 55 hz
Posted By: DYohn
Date Posted: March 16, 2006 at 1:02 PM
Sounds like you are clipping the amp, either with a bad input signal or an over-driven gain or both, and thus overpowering the speakers. Plus, it may work for your setup, but 55Hz low-pass is pretty low... not that that will blow your speakers by itself, but it may be the reason your gain could be set too high. ------------- Support the12volt.com
Posted By: forbidden
Date Posted: March 16, 2006 at 1:06 PM
Are your subs a single 4 ohm coil or a dual 4 ohm coil, if the latter, how are they wired?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: the_one369
Date Posted: March 18, 2006 at 9:21 PM
my subs are dual 2ohm + 2ohm but they are bridged to the amp at 4 ohms
Posted By: Steven Kephart
Date Posted: March 18, 2006 at 9:41 PM
That's impossible. You could only provide a .5, 2 or 8 ohm impedance to your amplifier bridged with two 2 ohm DVC subs. Again, how are they wired?
Posted By: arrow12
Date Posted: March 18, 2006 at 10:24 PM
Steven Kephart is right. I've got an odd feeling you might be giving your amp a .5 ohm load, and that isn't good in your situation.
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That's my opinion. Take it, leave it, or correct me.
Posted By: blazinred99
Date Posted: March 19, 2006 at 1:16 AM
With a .5 ohm load wouldnt that cause the amp to fail or go into protection.
Posted By: forbidden
Date Posted: March 19, 2006 at 1:36 PM
This is exactly what I was thinking the minute I read the thread. You have sent the amplifier into thermal protection by asking it to drive a load lower than what it was designed to be able to safely and properly operate at. While the amp may indeed operate at this level for a finite period of time, the heat signature of the amp is going to go through the roof. Your best as safest bet to use these subs with this amp is to wire the two subs in a all series circuit and have a 8 ohm load running to the bridged terminals of the amp. Here is the proper way to wire these subs to this amp. 
------------- Top Secret, I can tell you but then my wife will kill me.
Posted By: the_one369
Date Posted: March 19, 2006 at 8:27 PM
i didn't put an "s" after amp but i am running like i said in my first post 1 kenwood amp to 1 alpine sub at 4 ohms
Posted By: Steven Kephart
Date Posted: March 19, 2006 at 8:51 PM
the_one369 wrote:
i didn't put an "s" after amp but i am running like i said in my first post 1 kenwood amp to 1 alpine sub at 4 ohms
Oh, I see now. You have 2 amps. Sorry, I missed that.
Posted By: the_one369
Date Posted: March 20, 2006 at 1:56 AM
well i think im going to start looking for some different subs any suggestions? im looking for the same quality sound that alpine offers but maybe something that i won't have as much problems with....price is not a factor.....but thanks for trying to help everyone
Posted By: arrow12
Date Posted: March 20, 2006 at 4:47 PM
When you are saying price is not a factor are you serious? Cause I can name a lot of subs that are pretty expense, but sound a lot better. Or do you want something in that general range?
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That's my opinion. Take it, leave it, or correct me.
Posted By: DYohn
Date Posted: March 20, 2006 at 5:00 PM
I'll say it again and maybe you'll listen this time: your amps are clipping. Either your gains are too high or the input to the amps is clipped or both. ------------- Support the12volt.com
Posted By: willdkartunes
Date Posted: March 20, 2006 at 6:47 PM
Regardless of what type of subwoofer you get, with them setup improperly, you will have problems with any brand.... Listen to DYohn. He knows more than you could possibly fathom. ------------- Do whatever makes you happy in life without diminishing the happiness of others
Posted By: the_one369
Date Posted: March 21, 2006 at 8:57 AM
well i mean under 600 a piece.....im not about to doubt what anyone knows on this site thats why im here asking for help....
Posted By: the_one369
Date Posted: March 21, 2006 at 9:03 AM
DYohn i checked both inputs to each amp and they are fine and i know that the subs could be pushed harder on the gain part because the gain is about half way up but not over half....is there anything else that you can think of?
Posted By: DYohn
Date Posted: March 21, 2006 at 9:47 AM
the_one369 wrote:
DYohn i checked both inputs to each amp and they are fine and i know that the subs could be pushed harder on the gain part because the gain is about half way up but not over half....is there anything else that you can think of?
The position of the gain control means nothing. How did you check the "input to each amp" to know it is "fine"? Did you set the amp gain using tones or music? Did you use a meter or set it by ear? Did you record the position of the volume control on your head unit when you set the gain and have you ever turned it up past that? ------------- Support the12volt.com
Posted By: the_one369
Date Posted: March 21, 2006 at 10:15 AM
i started from the headunit and checked the RCAs and followed them to my 2 amps for any cuts or exposed wires and made sure that they were connected properly....i set my cd player at the maxium that I listin to it at and i use a tone cd and did it my ear i know its not perfect but because i don't have a meter it'll have to do and i haven't turned it up past that level because my intenal speakers start to distort...i use to have 4 alpine type S subs in my car using the same 2 amps and i never blew one and i had those back in 2003 and just got rid of them....is there anything else that you can think of that i should look at or check out??
Posted By: Alpine Guy
Date Posted: March 21, 2006 at 10:28 AM
Something is definately not right in your setup, or your fingers on the volume control. I have ran 2000 watts rms through a type-r 12 in a ported box for a few months, gain was set with a DMM, never had a problem. Something is amiss when you blow a sub when pushing its rms rating, aka clipping. You may believe you set your amp up properly, but you can't go by ear when setting the gain, you cannot hear when a sub is clipping until you start bottoming it out which is beyond clipping. Do some reasearch on how to set you gain with a digital multi meter and i bet your problem will go away.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: DYohn
Date Posted: March 21, 2006 at 10:33 AM
Here's what I'd do: take the car to a good local car audio shop. Pay them for a couple hours labor to test your amps and make sure they are working OK, and to meter the outputs and reset your gain if the amps are OK. It is possible the amps are clipping due to them being bad or that they outputs are simply failing due to age and use. It is also possible your subs are defective (were they purchased from an authorized dealer? If so, go there and to have the amps and speakers checked.) I think you did what you could do, but it may not be sufficient in this case. Get some hands-on help, it''l be worth the money unless you like to keep blowing speakers. Then, if the amps are toasted, you are right there at the shop and can look at new ones!  ------------- Support the12volt.com
Posted By: the_one369
Date Posted: March 21, 2006 at 10:43 AM
well thanks again for the advice guys i was also wondering where i can pick a meter so i can learn how to tune them so i don't have to go to a shop and thanks again
Posted By: Steven Kephart
Date Posted: March 21, 2006 at 1:15 PM
The best "meter" to use to set gains is an Osciloscope. Here's one of the least expensive one's I've seen: https://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-290 However there are ways of doing it with just a standard multimeter. It won't be as accurate, but it will be much cheaper.
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