i would first like to thank all the contributers on this site. this is my first posting, and i have a question on subwoofer response with positioning an enclosure in my truck. i have a 2000 s-10 pickup regular cab. i was wondering if anyone has postioned a subwoofer towards the back of the cab, instead of the front. ive built sealed slanted front prisms for several single subwoofers, and have noticed the rear of the seat absorbing much of the sound. the standard sealed enclosure designs for small trucks, seem to give me the worst response and overall sq possible. i was thinking of a dual divided sealed slanted prism, using the front for the seat to rest on, and the back as the baffle. i would add blocks to each side for subwoofer clearance. any suggestions would be greatly appreciated. ty - mikel -
Replies (6)
cplkittle on 02/13/2007 22:46:23
This would be the same concept as a downfiring box. I can honestly say I have never tried that design, but it sounds interesting. In a small truck like an S-10, there is not much room unfortunately, and most designs are for the subs to be facing foreward and firing into the back of the seat. I do understand your dillema. The only thing about this design that would concern me is the integrity of the back wall of the cab. If it is flimsy at all, this might result in a vibration that would be more aggravating than anything, but would take away from the clarity of the sound.
In downfiring boxes, and you will want to consider this with your design, the speaker is not always 100% parallel with the surface it is facing. This causes some cancellation with the soundwaves bouncing back onto the cone of the speaker. I would suggest an angle of at least 5 degrees, with the opening at the top being greater than the bottom. This will help to reduce the cancellation and also project the sound upward and into the cab. You might also want some sort of fabric on the back of cab facing the speaker as well.
mikel on 02/13/2007 23:51:05
cp, i thank you for the response. from what i have studied one of the best setups, if you have enough room is 2 downfiring 8 " subs ported or sealed. however, my regular cab leaves me with not enough room. as for rearfing as you said its only sheetmetal. now i have some vb-1 sound dampening that i could cover the rear wall, but i have no experience with sound deadening sheets. its a very thin self adhesive vinyl material. will this absorb the sound and leave me in the same situation as the seat absorption? if so to limit car noise i could cover all areas except where the subs fire into to help. what do you think?
swez on 02/14/2007 09:50:34
This is the most difficult scenario a newbie can face. The limited space for the enclosure and firing position of the sub(s) have to be worked out very carefully or you'll not be happy with all the work when done.
Does your S-10 have a bench seat or dual buckets? Depending on your anwser, there are some options to look at.
Also, I have found in many cases that up-firing subs in a tall truck cabin works very well if one can make it fit. Down-firing will also do a good job, but Kittle has pointed out the key... an angled baffle panel works best to direct bass energy so that it does not bounce right back into the cone(s). Here, using some of the space under the front seat(s) for the enclosure(s), can be most beneficial. Mounting the amp(s) on the rear wall are a very good option as well.
Rear fired sub locations can be helpful if you use sound dampening on the back wall. Here again, angling the baffle panel works best to give one a wave guide for bass to escape and not bounce right back into the cone. Vinyl coatings tend to reflect bass pretty well. If the vinyl is too thin, metal resonances are common and can be very annoying.
Carpeted dampening materials tend to absorb bass. That's fine inside the box for rear wave absorbtion. Not as desirable as a wave guide surface.
Finally, porting can help with deep lows if the port is not obstructed by hard or absorbant materials in close proximity to the port output
vent(s). Can explain that in more detail later as needed.
Say more as you see fit,
Swez
PS Welcome to CK... we hope you enjoy the site and can obtain usable solutions for this project.
mikel on 02/14/2007 10:31:22
swez, its nice to finally speak to you. i have read many of your articles.subs facing up or down work great in larger or extended cab trucks. however, my only option is something like my slanted prisms, which i will modify to fire off the rear of the vehicle. in other words about a 75 degree angle for the seat to rest. and what would be the rear, in this case the baffle i will set at about 80 degress to let let the sound reflect and dispresr well in the vehicle. one thing i will like about this box will be minimal standing waves due to different angles. i will be lining the box with about 2 " of acouta stuff which will give me a qtc of about .8 which im looking for. and vb-1 without carpet should be covered throughout the entire rear wall you say? i appreciate all of your help thank you
cplkittle on 02/14/2007 12:14:43
If the rear wall was carpeted, I don't think it will muffle or absorb enough bass to make a difference. I was thinking along the lines of anti vibration for the rear wall of the cabin. It is definitely not the same as the 6" thick foam in the seat.
PL on 02/14/2007 14:01:46
Interesting Idea here!
I agree with Kittle, I dont believe the if the back of the cab has carpet its really going to absorb enough of the acoustical engergy produced to really make a difference.
The thing that could be an issue is Flex. Cab flex sounds like crap (pardon my french) and can be a real hassle to correct.
If your going to face the sub towards the back of the cab depending on how much power is provided you might find that the sheet metal will flex and rattle. (I've had this problem in the past and had to weld a couple bars of angle iron to the back of the cab to reinforce it). You might get by just fine, or you might have to add quite a bit of sound deadening to fix the problem (or worse, weld it).
If you have bucket seats I would suggest fabricating a center consol enclosure. I've done this in the past and works great =)
How much power do you running to the drivers?
-PL
Replies (6)
cplkittle on 02/13/2007 22:46:23
This would be the same concept as a downfiring box. I can honestly say I have never tried that design, but it sounds interesting. In a small truck like an S-10, there is not much room unfortunately, and most designs are for the subs to be facing foreward and firing into the back of the seat. I do understand your dillema. The only thing about this design that would concern me is the integrity of the back wall of the cab. If it is flimsy at all, this might result in a vibration that would be more aggravating than anything, but would take away from the clarity of the sound.
In downfiring boxes, and you will want to consider this with your design, the speaker is not always 100% parallel with the surface it is facing. This causes some cancellation with the soundwaves bouncing back onto the cone of the speaker. I would suggest an angle of at least 5 degrees, with the opening at the top being greater than the bottom. This will help to reduce the cancellation and also project the sound upward and into the cab. You might also want some sort of fabric on the back of cab facing the speaker as well.
mikel on 02/13/2007 23:51:05
cp, i thank you for the response. from what i have studied one of the best setups, if you have enough room is 2 downfiring 8 " subs ported or sealed. however, my regular cab leaves me with not enough room. as for rearfing as you said its only sheetmetal. now i have some vb-1 sound dampening that i could cover the rear wall, but i have no experience with sound deadening sheets. its a very thin self adhesive vinyl material. will this absorb the sound and leave me in the same situation as the seat absorption? if so to limit car noise i could cover all areas except where the subs fire into to help. what do you think?
swez on 02/14/2007 09:50:34
This is the most difficult scenario a newbie can face. The limited space for the enclosure and firing position of the sub(s) have to be worked out very carefully or you'll not be happy with all the work when done.
Does your S-10 have a bench seat or dual buckets? Depending on your anwser, there are some options to look at.
Also, I have found in many cases that up-firing subs in a tall truck cabin works very well if one can make it fit. Down-firing will also do a good job, but Kittle has pointed out the key... an angled baffle panel works best to direct bass energy so that it does not bounce right back into the cone(s). Here, using some of the space under the front seat(s) for the enclosure(s), can be most beneficial. Mounting the amp(s) on the rear wall are a very good option as well.
Rear fired sub locations can be helpful if you use sound dampening on the back wall. Here again, angling the baffle panel works best to give one a wave guide for bass to escape and not bounce right back into the cone. Vinyl coatings tend to reflect bass pretty well. If the vinyl is too thin, metal resonances are common and can be very annoying.
Carpeted dampening materials tend to absorb bass. That's fine inside the box for rear wave absorbtion. Not as desirable as a wave guide surface.
Finally, porting can help with deep lows if the port is not obstructed by hard or absorbant materials in close proximity to the port output
vent(s). Can explain that in more detail later as needed.
Say more as you see fit,
Swez
PS Welcome to CK... we hope you enjoy the site and can obtain usable solutions for this project.
mikel on 02/14/2007 10:31:22
swez, its nice to finally speak to you. i have read many of your articles.subs facing up or down work great in larger or extended cab trucks. however, my only option is something like my slanted prisms, which i will modify to fire off the rear of the vehicle. in other words about a 75 degree angle for the seat to rest. and what would be the rear, in this case the baffle i will set at about 80 degress to let let the sound reflect and dispresr well in the vehicle. one thing i will like about this box will be minimal standing waves due to different angles. i will be lining the box with about 2 " of acouta stuff which will give me a qtc of about .8 which im looking for. and vb-1 without carpet should be covered throughout the entire rear wall you say? i appreciate all of your help thank you
cplkittle on 02/14/2007 12:14:43
If the rear wall was carpeted, I don't think it will muffle or absorb enough bass to make a difference. I was thinking along the lines of anti vibration for the rear wall of the cabin. It is definitely not the same as the 6" thick foam in the seat.
PL on 02/14/2007 14:01:46
Interesting Idea here!
I agree with Kittle, I dont believe the if the back of the cab has carpet its really going to absorb enough of the acoustical engergy produced to really make a difference.
The thing that could be an issue is Flex. Cab flex sounds like crap (pardon my french) and can be a real hassle to correct.
If your going to face the sub towards the back of the cab depending on how much power is provided you might find that the sheet metal will flex and rattle. (I've had this problem in the past and had to weld a couple bars of angle iron to the back of the cab to reinforce it). You might get by just fine, or you might have to add quite a bit of sound deadening to fix the problem (or worse, weld it).
If you have bucket seats I would suggest fabricating a center consol enclosure. I've done this in the past and works great =)
How much power do you running to the drivers?
-PL
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