Attaching Amp To Back Seats?

Just curious how everyone put their amps and all on the back of their rear seats. I tried to manual drill w/ a handheld tool and it didnt work (broke the bit). lmk thanks

[FormulaNERD]

i just screwed the screws in with a screwdriver

[jabartram]

cordless drill with phillips tip and i put 3 amps and a capasitor.

reason also why i ask, it seems that hard plastic piece is fairly thin and a screw wouldnt be enough to hold the amp down (over time and driving conditions, mainly hitting those bumps and potholes u cant avoid) but if u say it works well for u guys, ill give it a try, to the cordless I go.

[Screamin eagle]

You won't have a problem with your amps on the back, I've got 2 amps and a cap on there and they are really sturdy. Don't drill first, just run the screws into the seat. Make sure when you put the seat down to mount them, you lay out your amps so that the seat will go back up. The first time I did it I got them all mounted and the little hole the seat fits back into was too small and I had to take them off and start over.

[FormulaNERD]

i did the same ^

[Vtolds]

Mine is just Screwed to the back of it, even though I dont use it.

[mike2002]

ive got a pretty heavy 5 channel mounted to the back, i just used the thickest screws i could find, they were #10's, maybe #12's, dont remember. i also put in these rubber washer things that were like 1/2" thick, when they screwed in they compressed to 1/4". to "abosorb" a little vibration, and space the amp away fromt he seat just a little for heat disipation. but mainly, i was worried the screws i was using were just a little too long

Just put the screws in, it's not too hard. I had no problem with mine.

[mikegett]

Mike2002 had all the right ideas. A amp should always be mounted with warshers. Air circulation is very critical to the efficiency of your amp. I could see the rubber adding a extra bennefit in vibration reduction.

i agree, it cant hurt, although the new sub box has taken a back seat because none of the lumber suppliers around here have 5/8" thick MDF, so im gonna have to spend some time driving around or something to find it, all they carry is 1/2 and 3/4, both of which are too thin and thick for what I have to work with and what I want.

[mike2002]

whats another 1/8"? ive always used 3/4". ive used 1/2" for ports, and its a pain to drill together without splitting the wood even after pre-drilling. you dont have to use mdf, marine grade plywood, or baltic birch, though more expensive, is preffered.

whats the best type of wood to use for sub boxes? i know theres a more expensive type than MDF, but I also dont want something that weighs more than MDF, im goin for a box lighter than what I have now but still sturdy enough to perform close to what the box I have now does, in one of the posts, i think its the mounting nitrous bottle to sub box, theres a design of what im working on, and i think its set up to weigh less but thats depending on finding someone to do some plexiglass work for me...either way this has taken a back seat to work on some appearance stuff thats taken precedence.

[Vtolds]

MDF is probably the Best 1 inch is a good thickness for them you can also make a box out of 1 inch thick lexan plastic.

[mike2002]

they make 1" mdf, but its really hard to find, and its like $40 a sheet, read this....its not from me, its off a audio forum

Most use 3/4" MDF for subwoofer enclosure construction due to its density, availability, and price. Better yet are super high-quality plywoods like birch or other void-free plywoods. Both are fine choices.

Avoid using particle board at all costs as it is too flaky, doesn't hold screws well, and swells up when it comes into contact with water.

Dan Wiggins of Adire Audio comments on MDF vs high-quality plywoods:

"In general marine grade plywood (or Baltic birch, apple ply, or any other void-free plywood) is superior for subwoofer use. The reason: stiffness.
Subwoofer cabinets WILL talk - they will vibrate. The key is to keep the cabinet from vibrating in the frequency range of the subwoofer. There's two ways to do it: push the resonance of the cabinet above the pass band of the driver, or push the resonance of the cabinet below the pass band of the driver.

To push the resonance above the pass band, we need to make the cabinet stiff. Stiffen something, and it resonates at a higher frequency. In this case, plywood is MUCH better than MDF. Plywood is simply stiffer than MDF, and that's why it is used for sub-flooring, cabinetry bases, and other strength-critical uses. It is the lamination of cross-oriented layers of wood that gives you the strength. No matter how you try to bend it, some of the wood fibers are in tension, which is where they are strongest.

To push the resonance below the pass band, we need to make the cabinet heavy. Add mass to something, and it resonates at a lower frequency. This is where MDF is better - it is much denser than plywood, and as such will take less thickness to lower the resonant frequency of the box. Of course, making a wall thicker also increases the stiffness, which runs slightly counter to the addition of the mass; the resonance still lowers, but not as fast as one would expect.

Overall, it's easier to make a box sufficiently stiff to not resonate below 300 Hz, than it is to make a box heavy enough to not resonate above 15 Hz. Bracing and stiff wall materials raise the resonance - bracing ADDS stiffness (as well as physical strength to hold up a driver, for instance).

Additionally, we need to consider the internal loss. As sound passes through material boundaries, it loses energy. The more layers, and the greater the changes in density, the more energy is lost. MDF is a VERY homogeneous material - it has little internal loss. Plywood, on the other hand, has multiple layers and has considerably higher internal loss. So acoustic waves will be better attenuated by plywood than by MDF.

And in the automotive world it is, IMHO, superior to MDF in two other significant ways: weight and water resistance. Less weight is always good - better gas mileage, easier to build/move, etc. And plywood doesn't swell and turn to mush, like MDF. In fact, marine grade plywood is VERY water resistant. No problems living in damp conditions in car trunks, or getting rained on occasionally.

Overall, if you don't mind paying an extra $25 a sheet for the material, I'd go with a quality void-free plywood (marine grade, Baltic birch, apple ply) over MDF, especially for subwoofers in cars. Lots of benefits, and only one real drawback (the slightly higher cost)."