Any safe way to mount amplifier to sub box?

 

Silver Member
Username: Gavbo211

Olney, IL US

Post Number: 985
Registered: Jan-05
I'm using a 93 S-10 extended cab as my daily driver right now, so i decided to pull out my system and stick it in this truck.. the problem is, space is a huge factor. I can fit my box in, and it takes up all of the passenger side of the extended cab area. I usually have something in the cab (book bags, luggage, etc.) so I need that little space behind the driver seat. Problem is, that leaves me with pretty much just the box to mount my amp on, which i'd prefer not to do, and no room to put an amp rack or safely mount it to anything else. is there any safe way to go about mounting it to the box? some kind of material i could put between the box and the amp that would help tone down the vibrations or anything? any help is appriciated, I'm trying to get it hooked up and ready to go asap.
 

Gold Member
Username: Jtown

Texas

Post Number: 3425
Registered: Mar-07
you could put the box on blocks/stilts and put the amp underneath the box. otherwise, the safest way to mount the amp to the box is to double or triple baffle the area the amp will be mounted to, as well as maybe a foam board or some rubber gaskets to further reduce the vibration.
 

Gold Member
Username: Nd4spd18

Philadelphia, PA

Post Number: 9448
Registered: Jul-06
http://www.bcae1.com/amplfier.htm


"Amplifier mounting:
DO NOT mount an amplifier on your subwoofer box. I know that there has been a great deal of discussion over mounting an amplifier to an enclosure and many people do it all of the time with no problems but those people probably build good enclosures from 3/4" (or thicker) MDF with extensive bracing. Most people (especially young impatient people) are too lazy to do that and build unbraced enclosures from 5/8 MDF. These enclosures will flex considerably more than a proper enclosure and will likely cause amplifier failure if the amp is mounted to the enclosure.
REASON:
When the woofer(s) moves in or out, the box flexes and therefore causes the sides of the box to vibrate. This vibration is transferred to the amplifier mounted to the box. All of the electrical components in the amplifier have mass. Inertia (an object in motion tends to stay in motion, an object at rest tends to stay at rest) tells them to stay at rest, the box vibration is trying to make them move. The energy from the box's vibration is transferred to the components through the electrical leads which are soldered into the circuit board. All of this will cause the components to break loose and therefore cause the amplifier to fail prematurely. Basically, the amplifier will commit suicide! :-) I'm not telling you this because someone told me it was bad. I've been repairing amplifiers since ~1985. Virtually every amplifier that's come into my shop with parts rattling around inside them have been mounted on the speaker box. It causes the legs of the semiconductors to break (which causes amplifier failure). It causes the capacitors to break off of the board (which can cause catastrophic amplifier failure). It causes solder joints to break on the semiconductors mounted to the heat sink. It causes transformer windings to grind into one another (which causes lots of smoke to pour out of your amplifier). People who repeatedly tell others to mount their amps on the speaker box because they've never had a problem remind me of people who drink and drive and say there's nothing wrong with it because they've never crashed their vehicle. Eventually, in both cases, problems will arise. "





On that page he also shows the best method to do it if you absolutely have to.
 

Gold Member
Username: Tatonka

-[Team Audible Insanity]-

Post Number: 2599
Registered: Mar-07

quote:

When the woofer(s) moves in or out, the box flexes and therefore causes the sides of the box to vibrate. This vibration is transferred to the amplifier mounted to the box.




Sounds to me like a poorly built box. If your box is built strong, you will not have any problems.
 

Gold Member
Username: Frkkevin

Team DLSSuperNatural...

Post Number: 6129
Registered: Nov-05
Even if the box is strong.. your still transferring energy from inside the box to the outside.. IE vibration

newtons law.. you can't argue the truth :-)

even if it were built with cement.. attach something to that cement and you will feel a vibration
 

Gold Member
Username: Tatonka

-[Team Audible Insanity]-

Post Number: 2603
Registered: Mar-07
I can't feel the vibration on my box with a triple baffle lol. I know there is still energy, but everything else in the car vibrates more than my box.
 

Gold Member
Username: Surferdude9371

Get loud or go home....

Post Number: 1591
Registered: Mar-07
mount it on under the box thats what i did i have a "ranger" ext cab
 

Platinum Member
Username: Glasswolf

Raccoon City, MI USA

Post Number: 12261
Registered: Dec-03
Nick, even if you can't see or feel it, the box does flex. It's one of the laws of physics with which you really cannot argue.
I have a set of home main speakers that I can crank till my ears literally hurt from the sound pressure, and yet I can also balance a nickel on it's edge on top of the speaker cabinet and it won't move while I'm doing this.
From first glance you'd think wow.. the cabinet doesn't move.. and while it is very well designed (should be for $3600 per pair back in 1987 dollars) it does in actuality, still move.. just much less than say, a plastic boom box speaker enclosure would.

Anyway, the problem lies in that with these very small vibrations being transferred from the sub, to the box, to the amp casing, and onward to the PCB inside the amp, the solder joints and SMT components on that PC board will also resonate and move, and eventually fail due to fatigue. You can and will shorten the life of the amp(s) in this regard, though there is no way to measure specifically by how much as there are too many variables.

If you absolutely must mount an amp to the sub box, try your best to isolate it with rubber stand-offs at least, to absorb some of that energy.
 

Gold Member
Username: Jakeyplaysbass

St. Louis, MO / ASU

Post Number: 3545
Registered: Jul-05
When i mount to a box i always use double baffle, a thin layer of rubber (home depot), carpet, and then rubber "feet" (i guess they are called stand-offs). In that order.
 

Silver Member
Username: Gavbo211

Olney, IL US

Post Number: 986
Registered: Jan-05
well damn guys.. thanks for all the info.

M.S. - that link was really helpful. i should have realized to check there before anything else.

The box is 3/4" and its a solid enclosure, i've had bad boxes before and learned that its best to put in the time, effort, and money and do it right the first time. double or triple baffle is what i was thinking, and i'll look into the rubber "feet", but even those extra couple inches may cause an issue with space.

P. Rick - have you ever had ventilation issues or problems with over heating with having the amp under the box? that would be my only concern with that idea, because it would have to be a very small space because too much higher and i wont be able to put the passenger seat back without having the box in the way.
 

Gold Member
Username: Tatonka

-[Team Audible Insanity]-

Post Number: 2608
Registered: Mar-07
That makes sense, Glasswolf. I took physics too long ago lol.
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