Help with Subs

[Fox]

Ok, so ive hooked up my subs and Ive had them in my car for 3 days....

Ive already snapped two 8 gauge power cables.... Snapped, not pulled loose, Snapped.

How the hell do you keep the subs mounted in place??? My box slides all over and it pulls the carpet with it sometimes, and its a pretty heavy box too. How do you guys do it? I mean if its just that you drive slow then i guess ill have to take it out but im hoping theres a sane way to mount it without having to screw holes everywhere.


Also, I have 2 sony 8s, should the box be ported? And i see all you guys face the subs towards the back, i guess this is to be superficial and for looks, but my 8s dont make much sound, Im pointing them towards the front. Will pointing them to the back make much difference?

[schneider252]

i have no idea about electionincs BUT

On e30tech.com I saw that one guy took his sub and cut a whole were the extra tire goes and he just sliped his bass in there, and then attached his amp to the bass. It loooked pretty good. Give it a gry.

[jllphan]

As for keeping your box stationary, I have always built the box, and made it to "fit" into an area, which prevents me from having to bolt it down. I drive anything but slow, and if you do the same, just go get some L brackets and screw the sucker to the floor above your spare. Just make sure to cap off the scew on the other side so that you don't puncture your spare ghead

As for porting your box. This will do two things. It will make your box more efficient (louder with the same input power), and more boomy. When I say boomy I mean not clean, punchy, and tight. You give up sound quality to gain volume.

As for facing the subs the other way, it has nothing to do with vanity . Low frequencies disperse in an omnidirectional manor. And as they do so, they gain strength for a given period of time. Without going into the theory of sound travel, the best way I can explain it, is you want the reflections of bass, not the direct sound wave. Aiming them away from you does just that, and actually improves sound quality and volume level exponentially.

[El Presidente]

That covered it pretty well. My boxes are also purpose-built, so I don't have any sliding. Short of clamping it down, you could also try attaching rubber feet. I have seen them used on some boxes and they work decently.

[BlantonG13]

go to Home Depot, they have these nifty little brackets I screwed into the floor. They were mounted on the floor and held the box around the corner. Try the wall trim section, even near the door hardware section in Home Depot...

[docrobot]

Aiming them away from you does just that, and actually improves sound quality and volume level exponentially.

I wouldn't go that far, unless you can turn your amp up to 11... B)

[jllphan]

Originally posted by docrobot@Jul 12 2004, 05:04 AM

I wouldn't go that far, unless you can turn your amp up to 11... B)

Well guess what, mine does. Most amps only go up to 10, but mine goes up to eleven.

[BlantonG13]

Alpine Bass Engine with Bass Engine capable amp

that makes for a few exponents

[bitcore]

There is a theory about wave doubling when the subs are facing rearwards, but since bass audio waves are so long at very low frequencies, it may not even matter. The wave doubling theory is that the audio will reflect off the back of the trunk, and double up with waves being emitted again, making it appear in the cabin that the sub is louder. Depending on the car, frequency being played, woofer, and enclosure type, this may or may not be noticeable at all. Way in the back, out of the way and along with the theory, seems to be the best option.

Porting an enclosure relies on a physics mechanics called wave doubling. You will get much more output (SPL) at the lower end of the sub's frequency response, but with the addition with unwanted harmonics and 'unloading' the woofer at very low frequencies. Ports are created for specific lengths, so there's time for the sound waves emitted from both sides of the woofer's cone to 'double up' and become louder. This is how you "tune" a ported box to have its peak output at the frequency you want. Although this produces much more output, there's a cost of quality. At the beginning and end of each bass burst, there will be much less SPL being emitted since there is no other wave that has been created by the other side of the woofer's cone to double up with. You also have issues with port noise, a whooshing noise, flaired ports help to solve this but dont fix the problem entirely. As jllphan said, in laymen’s terms, the system will sound more boomy. I wouldn't go so far as to say it's more "efficient," but in terms of making more noise, it gets the job done well.

You should port the box only if the speaker is designed for ports. If it's not, you can still do it, but the results can be a little weird.

As for woofer unloading, this usually only occurs at frequencies under 20 Hz, which isn't in much music at all. This is where the backpressure of the woofer isn't there anymore, making the driver's suspension much less springy, and allowing the risk of slamming the suspension or damaging the voice coil against the back plate from over-extension.


Just as a note: I hate Sony’s car audio equipment. Their woofer cones FLEX, their amplifiers have terrible harmonic distortion ratings, they just produce cheep, car audio equipment. The rest of their stuff isn't so bad, but their car audio department is horrid.