SPL Trunk 'Wall' Build Log

[hispls 5,000+ posts]

If your going to use the trunk as a box it's probably better if it doesn't rattle to hell and back

The box will be built into the trunk and the trunk should be entirely sealed off from the cabin. If anything behind the seats is rattling that would be a failure to implement this design correctly.

 

[Jonnyswboy]

The box will be built into the trunk and the trunk should be entirely sealed off from the cabin. If anything behind the seats is rattling that would be a failure to implement this design correctly.

Considering how much power and the cost of this build, the extra deadener would be justified purely as peace of mind to me (It's 0.8% of the total cost so I don't really care). I suspect the vibration can travel through the other surfaces in the car and end up vibrating in the trunk slightly. More deadener isn't going to hurt as far as I'm concerned.

 

[SlugButter]

When you wall off a vehicle, does making the cabin smaller raise or lower your vehicles resonant frequency?

 

[hispls 5,000+ posts]

I suspect the vibration can travel through the other surfaces in the car and end up vibrating in the trunk slightly.

If your trunk winds up rattling you should be looking at how well you sealed it off from the cabin. You absolutely should NOT be getting trunk rattling if you have sealed it off thoroughly.

When you wall off a vehicle, does making the cabin smaller raise or lower your vehicles resonant frequency?

Higher. You can usually guess where your best peak will be by measuring the cabin corner to opposite corner then dividing by the speed of sound and dividing that by 2 to find the half wave length.

 

[Buck 5,000+ posts]

If your trunk winds up rattling you should be looking at how well you sealed it off from the cabin. You absolutely should NOT be getting trunk rattling if you have sealed it off thoroughly.

Higher. You can usually guess where your best peak will be by measuring the cabin corner to opposite corner then dividing by the speed of sound and dividing that by 2 to find the half wave length.

That's not true. You're trying to be correct where it doesn't realistically matter, and you're not correct.

I've seen 2 american bass HD 12's flex the grill of a car and that's not even connected to the interior. Deadener stops rattling by lowering Fs of the metal by adding mass, adding mass to make the panel require more energy to move the same distance, therefore reducing flex from pressure.

Every single piece of metal on this car will vibrate with those subs LOL, probably everything with a 50 foot radius of this car is going to vibrate, if it's all correct.

Whether or not the box directly pressurizes the trunk is irrelevant, there will still be pressure differentials around the trunk panels, if not on the inside, then on the outside. Have you NOT EVER heard bass outside of car? That's why you'd deaden metal like he did, even if it's sealed off. It's still going to vibrate like crazy. Bass is still going to flex the trunk....there's bass on the outside of the car too lol. People driving next to him in traffic should probably deaden their cars too.

 

[1aespinoza 10+ year member]

People driving next to him in traffic should probably deaden their cars too.

Damn, good one.

 

[hispls 5,000+ posts]

I've seen 2 american bass HD 12's flex the grill of a car and that's not even connected to the interior.

So you're saying OP should probably preemptively deaden his grille?

I'm not having any of those issues with either of the wall builds in my yard, we needed just a little on the rear deck of the Civic (which we should have just gutted in the first place) but suit yourself. Obviously it can't hurt but I would apply only as needed after everything else is together.

 

[Buck 5,000+ posts]

So you're saying OP should probably preemptively deaden his grille?

I'm not having any of those issues with either of the wall builds in my yard, we needed just a little on the rear deck of the Civic (which we should have just gutted in the first place) but suit yourself. Obviously it can't hurt but I would apply only as needed after everything else is together.

Don't play, you know what I'm saying. Clearly I'm saying bass touches everything within a certain radius of the car; deadening the trunk still keeps it from making noise.

 

[hispls 5,000+ posts]

deadening the trunk still keeps it from making noise.

So will deadening the grille. Why wait to see if it even needs it?

 

[Breaker]

Fuckbthem yinglong. If you want lto lishen holds better above 15 and has a tad better discharge. They have much more powerful cells I'd use than yinglong

 

[Jonnyswboy]

That's not true. You're trying to be correct where it doesn't realistically matter, and you're not correct.

I've seen 2 american bass HD 12's flex the grill of a car and that's not even connected to the interior. Deadener stops rattling by lowering Fs of the metal by adding mass, adding mass to make the panel require more energy to move the same distance, therefore reducing flex from pressure.

Every single piece of metal on this car will vibrate with those subs LOL, probably everything with a 50 foot radius of this car is going to vibrate, if it's all correct.

Whether or not the box directly pressurizes the trunk is irrelevant, there will still be pressure differentials around the trunk panels, if not on the inside, then on the outside. Have you NOT EVER heard bass outside of car? That's why you'd deaden metal like he did, even if it's sealed off. It's still going to vibrate like crazy. Bass is still going to flex the trunk....there's bass on the outside of the car too lol. People driving next to him in traffic should probably deaden their cars too.

This was the idea floating in my head but I couldn't put it into words this well. Thanks.

 

[Jonnyswboy]

Fuckbthem yinglong. If you want lto lishen holds better above 15 and has a tad better discharge. They have much more powerful cells I'd use than yinglong

In 5s or 6s? 5s nominal is 12.5v which is a bit low. 6s is 15v which is too high for my PCM and amp as I would need to charge at 16v. 13.8v of the Yinlong is perfect. Also I would need 5 banks in order to match the 80AH of the Yinlong and I have a space constraint.

 

[Jonnyswboy]

Arrived damaged, going to have to send it back and get a replacement.

 

[Buck 5,000+ posts]

Arrived damaged, going to have to send it back and get a replacement.
View attachment 30531

Some cornhole was just throwing that around like a pillow man

 

[Jonnyswboy]

These subs aren't playing around. Since Sundown won't post T/S, I guess I can inform everyone that the RE of the D2 is 4.0. And they are confirmed rated for 3k.