Help: Subwoofer Keeps Blowing

[RosedaleGuy]

I had an audio shop upgrade the sound on my 09 MDX.

He left the factory amp in to power the rear and front speakers but added an MRX F-65 to power the side speakers and subwoofer.

Everything was fine but then I had him upgrade the side speakers to component Alpine SPR-175. One thing I noticed after the upgrade was that I have to crank the volume up much more than I did with the factory speakers. I guess the small factory speakers are more efficient. But then the sub blew on me. I thought maybe it was because my girl maxed the volume.

The sound guy replaced the sub today. Now today it seems it blew out again. I had the sub and base set very low, never maxed the volume (0-40) I went to 32. It seems like I was playing music, the Nav sound took over, and I could hear the sub making an awful sound while the Nav voice was directing me.

Now this new sub (10" Helix) seems blown.

1. What is going on here?

2. Is there something I can add to prevent the sub from ever blowing out?

3. Is this guy doing a bad job? He seems to know what he's talking about.

It seems to me that the sub is getting way too much power. If I raise the sound volume so the music is loud the sub gets too much power and blows?

Any help would be appreciated.

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[RosedaleGuy]

Anyone?

Some extra info:

I did some googling. I'm guessin that when replaced the factory speakers he didn't increase the gain on the speaker channels. New speakers needed more power so when I cranked up the volume using new speakers it fried the sub.

Is it possible to have everything setup such that even if you max out the volume, subwoofer and bass that it won't fry the subwoofer or speakers?

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Some specs:

Alpine MRX F65 amp:

110x4 at 4 Ohms

160x4 at 2 Ohms

320x2 in bridged mode

2 speakers Alpine Type R are 110RMS @ 4 Ohms

The Helix 10" sub is rated for 250RMS @ 2x2 Ohms 500RMS max

I don't understand what 2x2 Ohms means.

 

[Fi_ 10+ year member]

First things first get a 5 channel or a monoblock don't use a 4 channel on your subwoofers. The guy seems like a crappy installer in my eyes take it somewhere else.

Seems to me you have faulty amplifiers, bad voltage or just crappy tuning or wrong impedance load. Just take it somewhere else this is a mess...

2x2ohm means its Dual 2 Ohm Voice Coils.

 

[RosedaleGuy]

First things first get a 5 channel or a monoblock don't use a 4 channel on your subwoofers. The guy seems like a crappy installer in my eyes take it somewhere else.
Seems to me you have faulty amplifiers, bad voltage or just crappy tuning or wrong impedance load. Just take it somewhere else this is a mess...

2x2ohm means its Dual 2 Ohm Voice Coils.

Thanks for the reply. He used a 4-channel because he said removing the factory amp could cause problem so he added the 4 channel to drive the front doors and sub.

The guy is going to try and fix it. It seems to me that when he added the speakers he didn't re-tune the system.

I asked him if it was possible to set it up so that the sub can't be overpowered. He said it wasn't possible. That doesn't make sense to me. Shouldn't it be possible to set the sub gain such that at max subwoofer, max base, max volume the sub won't be overpowered?

I don't always want to worry that if I turn the volume up too high or if I lend my car to someone they may push the sound too hard and blow my sub.

Thanks in advance.

 

[MisterDeadeye 10+ year member]

It doesn't matter if you're using a one, two, four, or five channel amplifier. Don't listen to stupid comments.

When you get back to the audio shop, ask the guy what he set the gain at, and at what volume. If he doesn't have an answer, you need to go somewhere else. What was the first sub you used, and what amp?

Is your sub in a sealed, or ported box? Could you smell your subwoofer before it blew, or was there some other problem? And is there any way you can record a video with the sound you hear while using the navigation? Maybe it's possible to use different voices with your navigation system. See if the noise is still there with another voice, if possible.

You usually don't want to max out the volume of your head unit because it can cause heat issues. How are your speakers set up? Are they in the stock location? Sealing up your doors will help make your speakers sound better(you can use weatherstripping as a gasket for the speakers, or get some butyl rope, modeling clay, silicone gasket maker, etc. If your doors have huge gaping holes, you can fill them with aluminum, plywood, MDF, or plexiglass covered with some kind of butyl based damper(Audio Technix sound deadener or similar), or if you have none of that, you can just use two layers of the sound deadener, one on the outer side of the door skin, and one on the inner side.

If your head unit has a decent equalizer, you can also try to normalize the sound signature of your setup, or turn down the gain on your sub(if your sound guy can't fix the issue, and if you can't deaden your doors).

 

[RosedaleGuy]

Thanks for the help. The sound guy will work on it tomorrow. I'll ask him about the volume/gain like you suggested.

Is your sub in a sealed, or ported box? Could you smell your subwoofer before it blew, or was there some other problem?

It's in a custom sealed box. I didn't smell anything. There was one problem. When I first got it I tried to play Amy Whinehouse "Back to Black" and the base sounded gargled. Other songs sounded fine.

And is there any way you can record a video with the sound you hear while using the navigation? Maybe it's possible to use different voices with your navigation system. See if the noise is still there with another voice, if possible.

I now suspect it was already blown when I heard the distortion from the nav voice.

You usually don't want to max out the volume of your head unit because it can cause heat issues. How are your speakers set up? Are they in the stock location?

Speakers on the doors and tweeters on the dash. Also front and rear speakers.

Sealing up your doors will help make your speakers sound better(you can use weatherstripping as a gasket for the speakers, or get some butyl rope, modeling clay, silicone gasket maker, etc. If your doors have huge gaping holes, you can fill them with aluminum, plywood, MDF, or plexiglass covered with some kind of butyl based damper(Audio Technix sound deadener or similar), or if you have none of that, you can just use two layers of the sound deadener, one on the outer side of the door skin, and one on the inner side.

Will this make a very noticeable difference? I feel moving from factory speakers to Alpine R was just a slight difference.

If your head unit has a decent equalizer, you can also try to normalize the sound signature of your setup, or turn down the gain on your sub(if your sound guy can't fix the issue, and if you can't deaden your doors).

I tried that. The sub lowest level is -6. I had it between -3 and -6. Also had the base set way down.

 

[whitemax 10+ year member]

Also, take a look at your enclosure. Make sure that it is totally sealed. Push on it carefully to see if you hear any air leaking through.

 

[Rich00 10+ year member]

I just did an install in my civic si with "premium sound" basically same setup. If you used he factory amp then that's a big no no with aftermarket speakers. You new to bypass the factory amp before it will sound good. I had a custom harness made to bypass my amp and got it installed with no problem.

 

[SourDeez 10+ year member]

Ok.. just stop. Bring it somewhere else dude.

He probably wired your sub down to like a half ohm or something by accident and it just locks up instantly

 

[RosedaleGuy]

He said he's done fixing the issue. It appears he accidentally set the crossover all the way up. I think that explains why the Nav voice was creating so much noise in the sub. He also had the gain too high on the sub and too low on the front speakers which what I suspected.

Rich00,

The factory amp is still powering factory speakers, The new F65 amp is powering the aftermarket front door speakers and sub. But you're right bypassing the factory amp is probably the better choice.

 

[groundpound4200 5,000+ posts]

Wait what? He's done fixing the problem? So the problem is fixed or he is no longer going to warrantly his install?

 

[SourDeez 10+ year member]

He fixed it.. by fix it he means instead of having the gain on the sub cranked and the gain on the speakers all the way down he leveled them out lol

 

[DARKHART 10+ year member]

I would seriously look into another shop.....setting the gains and xover point should have been done at inital install....also I'm concerned with how he got his input signal to the aftermarket amp....you shouldn't be getting factory nav voice through your subs, crossover settings or not...he sourced the wrong input signal....

 

[DARKHART 10+ year member]

First things first get a 5 channel or a monoblock don't use a 4 channel on your subwoofers.

He doesn't need to purchase a 5 channel...people have used 4 channel amps with the front two in stereo and rear two bridged to a sub for years, that's why that function is there...I currently have a SAX 100.4 running that way now...

He probably wired your sub down to like a half ohm or something by accident and it just locks up instantly

This statement really makes no sense....unless it's some super high current and high wattage beast this wouldn't be possible, the 4 channel amp would fry first or at least go into protect mode.....

 

[SourDeez 10+ year member]

This statement really makes no sense....unless it's some super high current and high wattage beast this wouldn't be possible, the 4 channel amp would fry first or at least go into protect mode.....

It totally makes sense. Running a cheap 4 channel amp and a cheap sub at .5 ohms and crankin the gains up... not good