noise from subwoofer box
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=115252
Printed Date: May 19, 2024 at 12:14 PM
Topic: noise from subwoofer box
Posted By: jdubicki
Subject: noise from subwoofer box
Date Posted: July 23, 2009 at 2:10 PM
Hey Guys, I Have a question, please don't laugh. I am just trying to get all the info before I make my next move. With my trunk open and my stereo on the right sub makes a vibrating buzz every time it hits. It is not very loud, and you can't even hear it when your in the car. I have some theories as to why this may be happening. Kepp in mind that as far as I know the left side is fine. I'm thinking the enclosure could have air leaking into it or the sub is seated perfectly against the box. I have tightened screws as tight as I can get them. The surronds on both sub are cracking all around the sub where it attaches to the basket. I can't tell if it is actually damaged, or just wear and tear. I know I will have to repair the surrounds eventually (wife won't let me get new subs). I'm also pretty sure that the voice coil and the guts are fine as well. Besides that the whole system plays just fine. I was also thinking that it could be where my crossover is set. I have an Alpine MRP-M500 set between the 75 and 100 marks. I'm guessing this is about 80 to 85 HZ. Let me know what you guys think. Am I making this out to be more than it is, or do I have a problem to deal with. Thanks in advance. ------------- 2005 Honda Accord DX
Replies:
Posted By: DYohn
Date Posted: July 23, 2009 at 3:05 PM
Assuming it is not simply something rattling in your trunk, the sound is either the speaker itself has come loose from the enclosure, or the voice coil is seperating and the sub will soon die. What do you mean by "the surrounds are cracking"? ------------- Support the12volt.com
Posted By: jdubicki
Date Posted: July 23, 2009 at 3:15 PM
I means they are begining to show signs of wear and are separating. It's not bad though. I will try to photograph it tomorrow. I guess the idea of the coil makes sense as well. Although I am NOT abusing the equipment (ie. pushing it to the limit with the volume and the gains) I am running a 500 watt amp at 2 ohm to a pair of 200 watt RMS/400 watt max subwoofers.
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2005 Honda Accord DX
Posted By: DYohn
Date Posted: July 23, 2009 at 3:21 PM
If the surrounds are "separating" they need to be repaired. ------------- Support the12volt.com
Posted By: jdubicki
Date Posted: July 23, 2009 at 3:24 PM
I will repair them. What about my power to sub ratio. Am I doing more wrong than good??
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2005 Honda Accord DX
Posted By: DYohn
Date Posted: July 23, 2009 at 3:31 PM
jdubicki wrote:
I will repair them. What about my power to sub ratio. Am I doing more wrong than good??
That amp could certainly blow those woofers. How did yu set your gain? ------------- Support the12volt.com
Posted By: jdubicki
Date Posted: July 24, 2009 at 7:16 AM
Gain is set at a little above 0.5V. It's basically between that and 75% full power. I have a low voltage radio though so that should not matter. I am actually going to purchase a remote gain control because on some sources I could come down on the sub gain a hair or two. Here is the deal though, I used to have these hooked up to an MTX Thunder 895. That amp was giving them 320 watts at 12.5 volts. The alpine documentation says it pushes 500 watts at 14.4 volts. I know for a fact that my head unit is not putting out a 14.4 volt signal. This is why think it is either the surround or possible the box itself, but I'm not totaly writing off the coil.
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2005 Honda Accord DX
Posted By: DYohn
Date Posted: July 24, 2009 at 12:10 PM
In other words you never set the gain properly. I bet your amp is clipping and that has damaged at least one of the voice coils. Please read the "How to set your gain" thread on the Hot Topics forum. You also state: " I know for a fact that my head unit is not putting out a 14.4 volt signal. " to which I say, HUH? The operating voltage of an amplifier is the system voltage coming from your alternator and has nothing to do with the preamp voltage from your head unit. ------------- Support the12volt.com
Posted By: jdubicki
Date Posted: July 24, 2009 at 12:18 PM
OK, point taken. What I was trying to get at was that I didn't think I was actually getting the full 500 watts out of the amp. I have read the sticky on how to set the gain. I have tried to be extremely careful as not to introduce distortion into the system. If I set the gain any lower I get no bass at all. I guess there really isn't much I can do now, if the colis are going to burn up theres not much I can do about it cause I can't replace the subs as of now. Let me ask you this. Am I going to cause damage to the amp if the coils do burn out??
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2005 Honda Accord DX
Posted By: icearrow6
Date Posted: July 24, 2009 at 12:20 PM
jdubicki wrote:
... I know for a fact that my head unit is not putting out a 14.4 volt signal. .
Wow, i don't know any HU that can put out 14.4V rca. LOL
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Posted By: jdubicki
Date Posted: July 24, 2009 at 12:24 PM
Wow, i don't know any HU that can put out 14.4V rca. LOL
[/QUOTE] That's what I'm trying to say. Does anyone have a guess as to how much power my amp might be putting out?? If it matter my RCA outputs are 2.5 volts. ------------- 2005 Honda Accord DX
Posted By: jdubicki
Date Posted: July 24, 2009 at 12:57 PM
Alright everybody, it seems that was majorly misunderstanding the whole RMS wattage at 14.4 volts issue. I just got off the phone with Alpine Tech Support and they tell me that If I blow a coil on the sub it will not damage the amp. They tell me it will go into protect mode. Do you agree. I want to replace the subs, I just can't do it right now. I just want to know if I can play the sub until they finally die with no worry of amp damage. Thanks.
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2005 Honda Accord DX
Posted By: DYohn
Date Posted: July 24, 2009 at 1:09 PM
Your amplifier is capable of full output. The voltage from the head unit does not change the output capability. But this is why you must set the gain properly: to match the input sensitivity of the amp to the output voltage of the HU. Otherwise you can drive the amp into clipping, and this can fry the voice coils of your subs. I suggest you need to set it properly or get some help from a pro and have it set or else the good sub will fry too. Or ignore this advice and bang away until it dies. It's your money. ------------- Support the12volt.com
Posted By: icearrow6
Date Posted: July 25, 2009 at 12:13 PM
jdubicki wrote:
Wow, i don't know any HU that can put out 14.4V rca. LOL
That's what I'm trying to say. Does anyone have a guess as to how much power my amp might be putting out?? If it matter my RCA outputs are 2.5 volts. [/QUOTE]
The RMS power of the amp at 14.4V is the input voltage form the BATTERY, not the voltage from the radio. As stated above the amp is perfectly capable to drive the maximum power without having the gains at "maximum". Gains are sensitivity settings, NOT volume knobs. -------------
Posted By: jdubicki
Date Posted: July 27, 2009 at 8:06 AM
I understand that gains are not volume control knobs. You guys are totally misunderstanding what I am trying to get across. Let me see if I can try this one more time. I just want to to know the following. I am getting mixed advice on all of these issues. 1. With the amp gains set properly, my 500 watt amp eventually destroy my 200/400 watt RMS/Peak subs?? 2 If a voice coil on my subs do fail, will it damage my amp?? Alpine tell me that it will go into protect and will not damage the amp. Do you agree?? That's pretty much it. the reason that I ask is because the amp is new and I don't want to mess it up. The subs however, are old entry level subs that I would like to upgrade EVENTUALLY. I just want to know if I can continue to listen to my system (WITH ALL GAIN LEVELS SET CORRECTLY). without fear of damaging the amp. I apologize for my ignorance about voltage. You guys have set me straight so now I understand how it works, thank you ------------- 2005 Honda Accord DX
Posted By: DYohn
Date Posted: July 27, 2009 at 9:48 AM
1) Yes, it could if you run it full out. It's not likely, though. 2) Not likely assuming the amp works the way it is designed to work. ------------- Support the12volt.com
Posted By: jdubicki
Date Posted: July 27, 2009 at 10:15 AM
Thanks for all of yor help.
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2005 Honda Accord DX
Posted By: jdubicki
Date Posted: September 02, 2009 at 4:15 PM
Ok, I figured out the problem and feel like a total pet monkey about it. It only took me 2 months to figure it out. Seem is had the pos and neg wires correct on the amp, and backwards on the sub box. Everything sounds good now.
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2005 Honda Accord DX
Posted By: i am an idiot
Date Posted: September 02, 2009 at 7:37 PM
The wattage at 14.4 volts is referring to the battery voltage, not the rca voltage.
Posted By: stevdart
Date Posted: September 02, 2009 at 10:21 PM
jdubicki wrote:
Ok, I figured out the problem and feel like a total pet monkey about it. It only took me 2 months to figure it out. Seem is had the pos and neg wires correct on the amp, and backwards on the sub box. Everything sounds good now.
It happens all the time. That's the first thing people don't check. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
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