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Ndnkobra

A general question about bass and how it works

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I have a question, it might sound stupid but i've been wondering about it for a while. its about a damplified trunk versus one that isnt. Of course, when a sub makes a sound (namely bass) in a trunk that isnt so sturdy, or the subs just hit really hard, it makes a rattling. Does the sound (bass) that is emitted from the trunk rattle, actually lost bass? Like the sound is converted into that shitty noise rather than transfering into the cabin, and hearing a more pleasant bass? And if a trunk gets damplified (thats just the wording i use :P), the dampening mat does a job of stopping that noise, but does it just do that? What i mean is, it'll stop the rattle, but will the bass still be lost and absorbed due to the matting, or will it travel into the car cabin like its supposed to? Thanks for any answers guys!

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yep..the rattles is energy from the sound waves changing mediums to your car. so dampening them well help reflect the sound instead of converting it to the car as rattles.

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Since the trunk lid is moving the wave that hits it is going to jump around and change it's sound too, that's why in the extreme class they use cement. Deadening helps a lot not only with rattle but you might see a +3dB gain in the cabin, especially SUV's. It's the same for the roof, flex is bad, but it's probably on a small scale. You want a box inside a box, not a box inside jello. Isn't having a box in a trunk like having a bandpass box that's seperated? If your roof flexes1-2" and is 50x50 that's 2500-5000 square inches of airspace being changed rapidly.

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I can be a personal testament to this...

I first installed my 2 15" Fi Q's without sound dampening, and expectedly, the sheet metal immediately surrounding the trunk rattled obnoxiously, diminishing the volume of bass heard both inside and outside the car...

After pasting the inside of my trunk with Damplifier Pro (and some appreciable amount of weatherstripping around the license plate and related trim) the bass inside/outside the car has improved what seems to be tenfold... when I demo my system the first thing people notice is the lack of "ghetto" trunk rattle... I mean, if you know instruments.. it's something like playing a note on the guitar with the frets buzzing - yeah, you will generally recognize the note being played but the resulting distortion takes energy away from sound...

sql54 was precisely right - the energy being wasted on flexing and vibrating the panels of your car is that much less sound energy reaching your ear... simple physics/fluid dynamics (without getting too complicated) if you think about it =)

So in short, yes, sound deadening is a great investment for any serious audiophile... and yes, Damplifier is a surefire way to go :drink40:

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Since the trunk lid is moving the wave that hits it is going to jump around and change it's sound too, that's why in the extreme class they use cement. Deadening helps a lot not only with rattle but you might see a +3dB gain in the cabin, especially SUV's. It's the same for the roof, flex is bad, but it's probably on a small scale. You want a box inside a box, not a box inside jello. Isn't having a box in a trunk like having a bandpass box that's seperated? If your roof flexes1-2" and is 50x50 that's 2500-5000 square inches of airspace being changed rapidly.

That Theory Has Been Proven Wrong, Deadener Will Actually Lower Your Score.

Most Sound Deadeners Absorb Acoustical Energy, Not Reflect It.

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Deadener can raise or lower score. Depends on the install. I've heard of people losing 4dB by using the stuff. Others have gained that and possibly more by using it.

I gained 1dB just by doing the very front of the cabin. 96cu.ft of deadener if I remember right.

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when applied to the rattling parts how does that take away from the sound?

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