How to Improve OE Sub Bass Quality and Eliminate Vibrations

Supbrah

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tadda, I just want to add my 2 cents here and thank you for all of the work you did on the this. Your instructions and explanations are spot on and the detailed photos with links to the products you used are extremely helpful. My only problem here is that I don't get the satisfaction (and frustration) of figuring this all out for myself. ;)

Thank you for sharing your knowledge with the rest of the group.
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tadda

tadda

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tadda, I just want to add my 2 cents here and thank you for all of the work you did on the this. Your instructions and explanations are spot on and the detailed photos with links to the products you used are extremely helpful. My only problem here is that I don't get the satisfaction (and frustration) of figuring this all out for myself. ;)

Thank you for sharing your knowledge with the rest of the group.
Ha!

And thanks! I'm sure there are other areas that can be identified that require further improvement and I welcome others insights and contributions...

I find projects like this analogous to an onion, where as when you start peeling back the layers more is revealed...
 
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tadda

tadda

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***First post in this thread has been updated to include enclosure liner template, rear panel foam template, and details on how the install rear panel exhaust ports***

Installing Rear Panel Exhaust Ports...
  1. Cover the front carpeted area of narrow rear panel to be cut with tape and mark a 2" diameter circle
  2. Use a dremel tool with disk to rough cut out the plastic panel within the marked circle
  3. Use a small dremel grinding drum to finish the edges of the port hole
  4. Cut the black OE panel insulation in the the center of hole and fold back on either side
  5. Insert 2" exhaust port
  6. Use tie wrap to hold thin black OE panel insulation along side walls of exhaust port
  7. Secure port to rear panel with drops of epoxy at edges touching rear panel and port walls
I also placed black metal speaker mesh (4" x 4") over the three elongated holes and secured in place with 3m tape...

subwoofer 7b ported rear panel.jpg
 
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Half Vast

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@tadda , I just gotta say top notch effort here! You've definitely put quite a bit if thought into this and it shows in the details. Since I've had my car I've thought the bass was a bit muddy for my tastes and never could find good EQ settings that would overcome that muddiness. I had a few other mods I wanted to do but this one now rises to the top.

Thanks for sharing this with the community. If you're ever in my part of VA, the first beer is on me!
 

Hakkim23

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The rear speakers are not the problem, the signal is. Set the speakers to full rear fade and you will see, they do not do much because they are being told not to do much.
Yeah but it doesn't look so good and it's like one of my not so favorite parts about the car
At least we can fix that with an aftermarket subwoofer
 
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tadda

tadda

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@tadda , I just gotta say top notch effort here! You've definitely put quite a bit if thought into this and it shows in the details. Since I've had my car I've thought the bass was a bit muddy for my tastes and never could find good EQ settings that would overcome that muddiness. I had a few other mods I wanted to do but this one now rises to the top.

Thanks for sharing this with the community. If you're ever in my part of VA, the first beer is on me!

Thanks :thumbsup:

The basic components of our Supras' sound system are actually very good...It's the application and some design issues that just required further attention and refinement for a relatively low cost...

In addition to the improvements made to the OE Sub system, these are all the other audio related system settings I currently have in place or selected...
  • ASD / Active Sound Design (off using Bimmercode)
  • Surround (off)
  • Speed Volume (+4)
  • Balance: (0)
  • Fade: (front +2)
  • Broad Bass (+4)
  • Broad Treble (-1)
  • Equalizer (shown below) which to some degree is subjective based not only on environment and components but also musical sound preference and hearing deficiencies as well...
Equalizer settings newest.jpg
 
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JasonO

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Yeah but it doesn't look so good and it's like one of my not so favorite parts about the car
At least we can fix that with an aftermarket subwoofer
If you are talking about the subwoofers, there are no direct drop in that changes the aesthetics. The factory grills still need to drop over them as they are 10 inches in diameter. Maybe @tadda has a picture of how they look off, but I don’t and can’t as I’ve ripped my factory box out and replaced it entirely.

When I was talking about rear speakers, I was talking about the 4” and Tweakers, not the sub. The mids and highs in rear are sent a heavily processed and attenuated signal. There is no point spending money on them if you are using the factory amp.
 

LeoLee2017

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I'm a retired Engineering Exec and Veteran as well (Former Marine)...I did get into high end audio as a hobby during the 80s and 90s and the interest has carried into my later years...

I suspect the rattling and design error (i.e. placing a panel directly over the elongated exhaust ports) was due to cost cutting and other priority / design decisions made by Toyota....

The project is fairly straight forward and once you remove the narrow rear cover things will become much clearer....The most difficult part was cutting 2 port holes in the rear narrow panel which I used a dremel tool....

And yes, I'm extremely pleased and satisfied with the results and sound quality now....This made me reconsider having to replace the subs...For now I'm very content....
Hello Tadda,

I hope you are doing well!

Well, I just couldn't find anyone to help me with the modifications that you recommended. As we all know, we are in the middle of the social distancing crisis. But usually, friends don't believe in social distancing when they need money. hahaha

I'm just going to wait for the 2021 models to hit the market to see if they fixed the issue. However, it's funny how Toyota has never heard of the rattling. Everyone here should file a complaint with Toyota consumer affairs. Maybe they will find a fix at their cost including labor.
 
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tadda

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Hello Tadda,

I hope you are doing well!

Well, I just couldn't find anyone to help me with the modifications that you recommended. As we all know, we are in the middle of the social distancing crisis. But usually, friends don't believe in social distancing when they need money. hahaha

So I took the Supra to a Toyota dealership. The master tech opened a Task Case with Toyota. He added what he described as foam between subwoofer cover, plastics, and clips on the subwoofer and surrounding trim pieces. But he didn't drill the exhaust ports. Overall it improved 75% with the bass all the way. However, I still get rattling with some songs with heavy bass. I usually don't listen to the radio very loud and I can still hear the rattling. But overall, it improved allot. I'm just going to wait for the 2021 models to hit the market to see if they fixed the issue. However, it's funny how Toyota has never heard of the rattling. Everyone here should file a complaint with Toyota consumer affairs. Maybe they will find a fix at their cost including labor.
Glad to hear you were able to get some of the vibrations and rattling resolved...A few others on here also had Toyota Service add additional insulation, but unfortunately that doesn't fully address the root cause of the problems with the sub system... I'm really not surprised Toyota techs knew nothing about the bass vibration issues...They're not audio sound technicians...The Sub system clearly wasn't Toyota's top priority and I'd be surprised if the 2021s see any improvements to the bass sound quality...

Aside from resolving my low bass vibrations and rattling, the improvements I mention in this thread (i.e. lining metal enclosures, applying foam to the narrow rear panel, and adding exhaust ports), which were of equal importance to me, was reducing distortions, deepening and tightening bass response, and improving overall bass clarity...I'm still very pleased with the results....
 
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JasonO

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Hello Tadda,

I hope you are doing well!

Well, I just couldn't find anyone to help me with the modifications that you recommended. As we all know, we are in the middle of the social distancing crisis. But usually, friends don't believe in social distancing when they need money. hahaha

So I took the Supra to a Toyota dealership. The master tech opened a Task Case with Toyota. He added what he described as foam between subwoofer cover, plastics, and clips on the subwoofer and surrounding trim pieces. But he didn't drill the exhaust ports. Overall it improved 75% with the bass all the way. However, I still get rattling with some songs with heavy bass. I usually don't listen to the radio very loud and I can still hear the rattling. But overall, it improved allot. I'm just going to wait for the 2021 models to hit the market to see if they fixed the issue. However, it's funny how Toyota has never heard of the rattling. Everyone here should file a complaint with Toyota consumer affairs. Maybe they will find a fix at their cost including labor.
Toyota isn’t going to fix the remaining rattles, you can better spend your time and effort doing it yourself most likely.

If you had similar rattle locations as I did, several other areas need to be decoupled with 1/16” thick neoprene tape or similar in the back. The locations Tadda showed are one. The others I found are the upper portions of the rear pillar along with the interior cover to on the trunk itself (top center). These aren’t difficult to do, just start in the back and work forward and down for the most part.
 
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tadda

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If you had similar rattle locations as I did, several other areas need to be decoupled with 1/16” thick neoprene tape or similar in the back. The locations Tadda showed are one. The others I found are the upper portions of the rear pillar along with the interior cover to on the trunk itself (top center). These aren’t difficult to do, just start in the back and work forward and down for the most part.
Yeah, it's like playing a game of wack-a-mole...once you get rid of the major bass vibrations others become more noticeable!

I also placed felt backed adhesive strips on many of the cargo compartment covers in the rear cargo area...

For example, the center cover inside hatch (#12) needed a few strips placed along the edges to stop from vibrating badly...

hatch assemblies.jpg


upper hatch cover.jpg
 

LeoLee2017

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Glad to hear you were able to get some of the vibrations and rattling resolved...A few others on here also had Toyota Service add additional insulation, but unfortunately that doesn't fully address the root cause of the problems with the sub system... I'm really not surprised Toyota techs knew nothing about the bass vibration issues...They're not audio sound technicians...The Sub system clearly wasn't Toyota's top priority and I'd be surprised if the 2021s see any improvements to the bass sound quality...

Aside from resolving my low bass vibrations and rattling, the improvements I mention in this thread (i.e. lining metal enclosures, applying foam to the narrow rear panel, and adding exhaust ports), which were of equal importance to me, was reducing distortions, deepening and tightening bass response, and improving overall bass clarity...I'm still very pleased with the results....
I used the OBDLink MX+ and the BimmerCode app to stop the exhaust sound that plays through the speakers. It seriously helped the sound quality. But it increased the subwoofer rattling. I will have to find a local sound shop when the COVID-19 restriction are lifted so that they can perform your recommendations.
 
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tadda

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I used the OBDLink MX+ and the BimmerCode app to stop the exhaust sound that plays through the speakers. It seriously helped the sound quality. But it increased the subwoofer rattling. I will have to find a local sound shop when the COVID-19 restriction are lifted so that they can perform your recommendations.
hmmm interesting......After removing ASD (low freq faux engine noise) my bass was somewhat clearer and less distorted but I didn't experience greater rattling over what I already had....Perhaps removing the low freq faux noise overlay (which certainly cleans up the bass) simply revealed the underlying bass rattles that already existed ?

As I've mentioned earlier, cleaning up the sound system and all it's vibrations and rattles can be a bit like playing wack-a-mole...
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