How to Improve OE Sub Bass Quality and Eliminate Vibrations

OP
OP
tadda

tadda

Well-Known Member
First Name
Tom
Joined
Dec 14, 2019
Threads
24
Messages
1,251
Reaction score
2,157
Location
Arizona
Car(s)
2023 C8 Corvette Z51 2LT Coupe
Vehicle Showcase
1
Doh! Me and g/f did this mod today and put the wadding in the wrong way! :nono:

It didn't make sense to me as I figured the port from the sub would be blocked but guess I read the directions wrong.

I wish I had read this post or further back as I just now read through every page.

We'll fix tomorrow, but in the mean time it made a huge improvement!

Wanted to say thanks Tadda! Awesome job and awesome write up!
This pic might help clarify things...As you can see with the sub removed there is actually a top port and a side port ..you don't want to block either with the wadding.....

Sub enclosure padding 2.jpg


ported subs air flow.jpg
Sponsored

 

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
This pic might help clarify things...As you can see with the sub removed there is actually a top port and a side port ..you don't want to block either with the wadding.....
Thanks Tom - yes, that is how I figured it should be done (after doing it incorrectly lol).

Today we'll switch around the batting and tackle some of the other sound deadening (like the back piece).

Only part I'm missing is the self adhesive foam to block the underside of the (now ported) trim piece.

2 other questions if you don't mind:
1. Did you stick the foam strips to the trunk or to the trim piece?
2. I recall reading you used 1/4" thick (high) foam, would 1/2" or larger be too much? I have 3/16" at home and need to get thicker but would have more use for the 1/2" - 3/4".

2 other thing to add to the thread:
- I know a lot of people use Dynomat, but I have had extremely good luck with Peal and Seal for sound deadening (I have done my share of car audio) - it's about $20 for the roll.

It is a roofing material with foil on one side and tar on the other. When using, I clean the panel with denatured alcohol, stick on the Peal and Seal, then heat it up with a heat gun and press it down with leather gloved hands.

It works wonders (just as well as any sound deadening from what I have read) and will not peal off if applied with a heat gun (even without a heat gun it is very difficult).

It also works well for it's intended use ;)

Capture.JPG


- Although not the same vehicle, my X3MC has ID6 and the HK Audio. Below is my thread on adding an amp/sub which may help some people get pointed in the right direction if looking to add a sub: My Sub/Amp Install on my BMW X3MC
 
OP
OP
tadda

tadda

Well-Known Member
First Name
Tom
Joined
Dec 14, 2019
Threads
24
Messages
1,251
Reaction score
2,157
Location
Arizona
Car(s)
2023 C8 Corvette Z51 2LT Coupe
Vehicle Showcase
1
@spta97

My concern with using the "peal and seal" would be with respect to odor and outgassing...This may be fine to use in a sealed trunk area, but the Supra has an open hatch area and the odor will be much more noticeable...
 
Last edited:

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
@spta97

My concern with using the "peal and seal" would be with respect to odor and outgassing...This may be fine to use in a sealed trunk area, but the Supra has an open hatch area and the odor will be much more noticeable...
I used it in my X3MC (hatch, not trunk) and have not ever experienced any odor.

Initially I was concerned it would smell like a freshly paved driveway on hot summer days when used in my previous E46 M3 (trunk) but there is no odor at all which I could smell. Same is true for the X3MC which has a hatch as stated.

That's not to say there isn't something there at a chemical level, just nothing I have ever noticed or experienced.
 
OP
OP
tadda

tadda

Well-Known Member
First Name
Tom
Joined
Dec 14, 2019
Threads
24
Messages
1,251
Reaction score
2,157
Location
Arizona
Car(s)
2023 C8 Corvette Z51 2LT Coupe
Vehicle Showcase
1
FYI...

Just applied adhesive backed felt tape to a number of places around the edges of the plastic rear hatch brake light cover and contacting hatch surfaces....There was a good amount of vibration coming from this plastic cover, particularly obvious during very low bass notes...Vibration from this area has been eliminated...

Felt Tape in Self Adhesive

Hatch Cover 1.jpg


Hatch Cover 2.jpg
 
Last edited:

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
FYI...

Just applied adhesive backed felt tape to a number of places around the edges of the plastic rear hatch brake light cover and contacting hatch surfaces....There was a good amount of vibration coming from this plastic cover, particularly obvious during very low bass notes...Vibration from this area has been eliminated...

Felt Tape in Self Adhesive
Thanks for posting! Very timely as I am getting some vibration from this area as well.

I also seem to be getting a vibration from inside the woofer enclosure itself. At first I thought it was the ports, but I removed the entire piece and it persisted.

There also seems to be some sort of resonance behind the passenger seat.

More work to do on this...
 
OP
OP
tadda

tadda

Well-Known Member
First Name
Tom
Joined
Dec 14, 2019
Threads
24
Messages
1,251
Reaction score
2,157
Location
Arizona
Car(s)
2023 C8 Corvette Z51 2LT Coupe
Vehicle Showcase
1
Thanks for posting! Very timely as I am getting some vibration from this area as well.

I also seem to be getting a vibration from inside the woofer enclosure itself. At first I thought it was the ports, but I removed the entire piece and it persisted.

There also seems to be some sort of resonance behind the passenger seat.

More work to do on this...
Did you also apply silicone adhesive between the woofer grill and cover plate as I mention in my 1st post? ..Those had quite a bit of vibration until the 2 plates were isolated from one another using that adhesive....

I also stuffed quite a bit of foam in the empty cavities within the subwoofer cover itself...
 

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
Did you also apply silicone adhesive between the woofer grill and cover plate as I mention in my 1st post? ..Those had quite a bit of vibration until the 2 plates were isolated from one another using that adhesive....

I also stuffed quite a bit of foam in the empty cavities within the subwoofer cover itself...
I actually removed the grills to take them out of the equation but will do that.

For the subwoofer enclosure, I was sticking my hand in it to see if I could find where it was coming from - will try the foam but it sounds (as best I can tell) like it is coming from the woofers or the plastic boxes the woofers are housed in.

I guess the true test would be to take it apart and just have the woofers in their enclosures.

I'm starting to think that this was not a design flaw, but rather a way for BWM/Toyota to avoid having to spend more on rattle avoidance.

It's amazing how much more bass this mod creates - rattles were not present in the stock config!
 
OP
OP
tadda

tadda

Well-Known Member
First Name
Tom
Joined
Dec 14, 2019
Threads
24
Messages
1,251
Reaction score
2,157
Location
Arizona
Car(s)
2023 C8 Corvette Z51 2LT Coupe
Vehicle Showcase
1
I'm starting to think that this was not a design flaw, but rather a way for BWM/Toyota to avoid having to spend more on rattle avoidance.

It's amazing how much more bass this mod creates - rattles were not present in the stock config!
It's interesting you say this because the very reason for adding exhaust ports on the narrow rear panel was to eliminate vibrational noise due to the panels being placed directly infront of the chassis exhaust ports restricting exhaust flow and in turn caused hellish vibrations and distortions!

These issues I find are like playing wack-a-mole....you resolve one major issue allowing you to increase volume and improve bass response and other problems surface...

I've finally gotten to the point I can increase volume to 3/4, significantly increase bass levels, and experience no vibrations or bass distortions...

Hang in there!
 
Last edited:

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
It's interesting you say this because the very reason for adding exhaust ports on the narrow rear panel was to eliminate vibrational noise due to the panels being placed directly infront of the chassis exhaust ports restricting exhaust flow and in turn caused hellish vibrations and distortions!

These issues I find are like playing wack-a-mole....you resolve one major issue allowing you to increase volume and improve bass response and other problems surface...

I've finally gotten to the point I can increase volume to 3/4, significantly increase bass levels, and experience no vibrations or bass distortions...

Hang in there!
Ha ha! That's so true.

It's also hard to actually locate where rattles are coming from - not to mention it is no party to be crammed in the hatch of this car during troubleshooting.

What is surprising to me is I did not have any of these issues with my X3MC install. Could it be because I jammed foam (egg crate) in anything that would take it after I used Peal and Seal on anything I could reach, or the W7 with a 500w JL amp just masks the rattles? Build quality seems similar between the two vehicles.

My biggest issue was the license plate rattling which I solved with more peal and seal and adhesive foam strips. Comparing these HK woofers (I have the same under my seats) to my W7 is like comparing the brightness of a candle to the sun.

I am starting to lean towards disassembly and foam jamming/peal and sealing everything but it seems silly for two OEM woofers...aaaaaand it's not my car lol.
 

nosavingthrow

Well-Known Member
First Name
John
Joined
May 1, 2021
Threads
19
Messages
355
Reaction score
511
Location
Seattle, WA
Car(s)
2021 Supra 3.0 Premium, 2022 Mazda 3 Turbo
Question about the dynamat on the trunk floor: it sounded like this reduced road noise (hurray!), but I am curious if it makes it harder to hear the stock exhaust?
 

digicidal

Well-Known Member
Joined
Jan 13, 2020
Threads
3
Messages
1,033
Reaction score
1,354
Location
Las Vegas, NV
Car(s)
2020 Supra, 2020 RX350, 2007 4Runner
Question about the dynamat on the trunk floor: it sounded like this reduced road noise (hurray!), but I am curious if it makes it harder to hear the stock exhaust?
It should (slightly), but that can always be fixed by going with a louder exhaust. ?
 

spta97

Well-Known Member
Joined
Mar 19, 2021
Threads
8
Messages
267
Reaction score
169
Location
New York
Car(s)
2021 Supra, 2020 BMW X3MC
I initially had the same problem but solved it a different way... either one is cheap and easy though.
I actually used this on the Supra. Nice simple plate holder but two issues why I didn’t use it on my X3MC:

1) The amount of vibration coming through the hatch was enough to rattle the metal in the plate itself.

2) I already had an ///M license plate frame which I like and I was concerned that people may not notice the other ~32 ///M badges BMW placed in/outside the vehicle and neglect to give me proper respect :)
Sponsored

 
 




Top