Audio upgrade options

[tadda]

Did you play any music with the back cover off? How did it affect the sound quality? That cover has insulation padding right over those ports so I wondered what type of difference it made with it on vs off? I doubt the holes are used to tune the subs frequencies, that's more of the port design for that (width and length). I would imagine that they put the cutouts to decrease the bass resonating off the metal. If the air was completely released it would definitely cut down on the rattle and muddy muffle sound.

Yes, I did play deep bass music with the narrow cover panel removed...Bass seemed to have a somewhat deeper response with far less low freq vibration...

That insulation you see on the narrow cover plate isn't thick enough to cover over the 3 elongated openings...The insulations is apparently used to reduce that panel from rattling...

Also, with the narrow cover removed I did actually cover those 3 elongated openings while playing deep bass and the vibration was absolutely horrible with bass response noticeably lessened...

I'm wondering if a 2" hole punched into that narrow cover plate in front of those 3 elongated exhaust holes might help with both vibrations and improve low freq response?

Side note: there are quite a number areas that need to have vibrations eliminated within the rear cargo area...I've identified a number of areas but it';s like a game of wack-a-mole where you eliminate a few key areas and then start to notice other spots you missed!

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[30MilesOffshore]

I'm wondering if a 2" hole punched into that narrow cover plate in front of those 3 elongated exhaust holes might help with both vibrations and improve low freq response?

That was my thoughts too. I feel the cover could possibly be restricting the air flow. My biggest concern with the port is that I believe they ported the box to help with the fake exhaust "rumble" notes that are pumped through the speakers. They were using the port to create the Active Sound Design (ASD) versus using the port to actually tune the music. I'm gonna run a few tests trying a couple of different scenarios. I'll try with the ASD on/off, and the cover plate on/off, and I want to also try sealing off the port, plus slowing air flow down through the port by stuffing it. As far as the sound dampening, you are right about the "Whack-A-Mole", but you can never go wrong with putting it on everything, especially any thin metal pieces in the area.

 

[Guff]

I have the car fully stripped in the rear with just the subs bolted in. Sounds so much better than factory but that's just because the factory pre-production car I was driving around in before was rattling like a mf lol. Turning off Active Sound Design may have contributed to that.

 

[tadda]

...My biggest concern with the port is that I believe they ported the box to help with the fake exhaust "rumble" notes that are pumped through the speakers. They were using the port to create the Active Sound Design (ASD) versus using the port to actually tune the music. I'm gonna run a few tests trying a couple of different scenarios. I'll try with the ASD on/off, and the cover plate on/off, and I want to also try sealing off the port, plus slowing air flow down through the port by stuffing it...

I removed active sound design a while ago which did help cleanup the low bass sound quality but did nothing to reduce low freq vibrations...I have doubts they added those 3 elongated ports with ASD in mind...I'm fairly certain those 3 elongated exhaust ports where added in an attempt to reduce chassis vibrations...I found this by sealing off those those ports while listening to low bass and the vibrations went through the roof and low bass response was reduced...

That said, it will be interesting to hear what you do find as well...

I was able to eliminate nearly 90% of the low freq distortion and vibrational noise by eliminating faux engine noise (which is only active in sport mode), playing with the sound EQ, and adding felt padding in some key areas which I mention in earlier posts...

I think that rear narrow panel and 3 elongated exhaust ports (6 total) punch into the chassis are most likely the main sources for the remaining vibrations...As mentioned earlier, I would like to add a 2" port on the narrow rear panel in front of those elongated holes to redirect the exhaust energy into the cargo area rather than having it contained within that narrow plastic rear panel area...

I would also like to remove the entire woofer assembly (including plastic enclosure) so I can first line the exhaust cavity walls and floor with sound deadening mat and then add some 1~2" thick batting along the walls...I think there is enough room to work with to get some mat added there...

Reposted image for reference...

 

[30MilesOffshore]

I'm pulling everything apart but got to a part that I'm stuck on. Can someone chime in with some guidance? The sub baffle panel has two bolts behind the center console/arm rest area (#12 in earlier diagram from post #70).

I can not see those bolts at all. I've already removed the cup holder and storage cubby hole. Do I also need to remove the entire center console (circled in red) to access the two screws on the baffle board #12? Seems like overkill to me. Anyone have any tips to get to them? The center console is one really long solid piece.

 

[tadda]

All you needed to remove is the rear cubby cover and remove these 2 bolts shown below

 

[tadda]

@30MilesOffshore I'm sending you a PM

 

[tadda]

Anyone following this audio upgrade option by OEM Audio Plus? It's still under development...

I like that this system will also offer multi channel amp and dsp...My understanding is that with this kit our current "subs" would be used as woofers (using cutoff filter) and that an additional sub is added to the system...

OEM Audio Plus for Supra

FEATURES:

• Designed and tuned specifically for the Supra A90

• Supra-Specific Subwoofer System

• Multi-Channel Power Amplifier

• Pre-Calibrated Digital Signal Processor (64-Bit)

• Plug and Play Installation

Update:

I got a call yesterday from OEM Audio Plus letting me know there has been a delay in release date of their new system for the Supra which was originally planned for April and now looks more like late spring ...

Some other info they shared was that they have been refining the new system for the Supra over the past 4 months now and feel the OE speakers (minus the subs) are actually pretty decent and feel like they are now best utilized with the help of the new amp with dsp applied...With the new amp and dsp they also make better use of the front centers and speakers located directly behind the seats which are pretty much under utilized with the current OE system...

One thing I was slightly disappointed to hear is that they plan on deleting the OE subs all together and will use their own Subwoofer in a new location shown above...I shared with them that I thought our sub layout and controlling electronic could have been designed better and probably would be best utilized as lower mids and that perhaps they could investigate looking into providing a sharp cutoff filter to the OE woofers and use their sub as the primary sub...

I also directed them to this thread so they can get input from others....

 

[30MilesOffshore]

tadda, I totally agree with your thoughts mentioned above. My reference perspective is a little different as I keep comparing it to the BMW M4. It had actually had a nice system in it for OE. My expectations was that the A90 would sound similar to the M4 but was sadly dissapointed when I first listened to it. The two audio systems are night/day difference. After tearing everything apart and running a few mock audio tests these are my conclusions:

• The amp is under powered and not pushing enough to the speakers. In comparison to the M4, I rarely had to turn the volume half way to really have it cranking. With the A90 it seems like I have to run it at 3/4 volume to get the same results. It is very noticeable if you go from one vehicle to the other. One thought I had was if the amp in the M4 could possibly be switched out and installed in the A90. Another thought was a thread I found stating that the Z4 had a setting in the ECU that could be coded from a hardtop to a convertible. I feel that this setting might be coded in our system but I can't confirm this as of yet.

• It sounds like the subs are tuned to around 100Hz which is a very mushy range for subs. The M4 had more dynamic range and the bass was able to achieve lower Hz easily. Since the subs are setup on the rear deck, I was expecting better results vs the M4 as those were setup under the seats. I totally think relocated the sub to the rear hatch would definitely enhance the lower frequency range.

Overall, (new amp + dsp + sub install in rear hatch + filter applied to current subs) would definitely be the way to go!

 

[BienLaunchEdition]

This what I set mine at for a natural clean sound

How do I get to this screen?

 

[JasonO]

How do I get to this screen?

IIRC, settings, System settings, tone, equalizer

 

[Hakkim23]

Check this out!

 

[tadda]

How to Improve OE Subwoofer Quality and Eliminate Vibrations

I spent a fair amount of time over the past few weeks thinking about how to improve the Supra's subwoofers, which we all know by now, were not designed properly and as a result have issues when it comes to both vibrational noise and lower bass quality...

Some incremental improvements to bass response can be made by first removing the Active Sound Design (faux engine / exhaust noise) which is electrically imposed onto the bass signal when sport mode is selected ...I found that the ASD feature actually "muddies" the bass response and increases distortion and noise...

In addition, many of us have played with EQ settings in an attempt to optimize sound quality but the OE system still fell somewhat short...I also found that selecting the "surround" enhancement feature added to the phase distortion which resulted in reduced sound clarity...This is one of the first things I turned off and the system clarity was noticeably improved...

Here are my current audio settings:

• ASD / Active Sound Design (off - using Bimmercode)
• Surround (off)
• Speed Volume (+4)
• Balance: (0)
• Fade: (front +2)
• Broad Bass (+2)
• Broad Treble (-2)
• Equalizer (shown below)

These are my new EQ settings (below) after improvements made to current OE Subwoofer system...I can also now raise the volume to 2/3 of max with no low bass distortions or vibrational noise...

Now with respect to the OE subwoofer enclosure itself this is where most of the major improvements to bass response were made... I identified a few notable areas for improvement after observing a few pics posted of the cargo area stripped down and began to get to work...It should be noted that the only panel that needs to be removed in order to make the following changes is the narrow rear subwoofer panel seen from the cargo area...

First, lining the walls of both metal sub enclosures (which are indeed separated) with 1" speaker wadding improved lower bass response and bass quality by reducing distortions created by destructive waves within the metal enclosure..The wadding also serves to increase it's "effective" volume...Speaker wadding turned out to be a very good solution for this...

Enclosure Lining / Wadding Template (below): I was actually able to roll up the speaker batting cut from a template (shown below) and slip it through one of the elongated exhaust ports and then use a long screw driver to manipulate the cut batting to line the walls of the metal enclosure shown below:

Secondly, and most importantly is that the majority of the lower bass vibrational noise and bass distortion is actually caused by the narrow rear cover panel blocking the subwoofer exhaust energy...The solution here was to 1) Insulate the area within the narrow rear panel with 2" foam leaving the exhaust port open and 2) Adding 2" exhaust ports to the narrow rear panel...

Foam Cutout Dimensions (below):

Note: I didn't need to remove the narrow rear panel mounting brackets...I actually used a 4"h length of 2" foam and cut slits into the foam such that the foam could be worked in from the top behind each of the brackets...

I also added a 2"h x3"d foam strip in the center and (2) 1"h x 1"w foam strips on either side above exhaust ports, under the top cover, to fill some voids as shown in pic below...

View attachment 25647

Installing Rear Panel Exhaust Ports...

1. Cover the front carpeted area of narrow rear panel to be cut with blue tape and mark a 2" diameter circle
2. Use either a 2" hole saw or a dremel tool with disk to cut out 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...

I've also identified another area that needed to be addressed...I discovered this after implementing all these other improvements, thus allowing me to significantly increase volume along with raising bass EQ settings...What I found was that there was some exhaust port energy escaping from under the long narrow rear panel (which as I show in a few pics below) causing the rear floor panel to vibrate...Keep in mind that this is yet another design problem which causes the floor panel to vibrate where in-turn this vibrational energy is transferred to the cargo areas' side and back panels causing them to vibrate as well...

The solution here was to apply some adhesive back foam to the areas show below which eliminated any energy transfer under the rear cargo floor panel...

Shown below, I first applied 1.5"d x 4" L x 0.25" h adhesive backed foam strips above and below both exhaust ports to isolate them further from the top cover and floor....

Next, the image below shows where some exhaust energy from the 3 elongated ports was also being released under the large rear floor panel causing it to vibrate greatly...With the floor panel removed simply place your hand under the narrow panel and you'll see / feel the exposed gap ...

Shown below are the locations where 2 adhesive back foam strips were applied to underside of exposed narrow rear panel ...The left adhesive backed foam strip was 1.5"D x 11" L x 0.25" H and the right foam strip is 1.5"D x 6" L x 0.25" H...This essentially sealed off the gap where the exhaust energy was also being channeled...

As a result the large rear floor panel vibration has pretty much been eliminated and side and rear trunk panels no longer vibrate during low bass / high volume music passages....

As far as materials, I used Noico RED 315 mil Sound Insulation , which I already had available for beginning my next project of eliminating front door speaker vibrations ....

Here is yet another area that required attention for eliminating subwoofer grill rattle / vibrations...I did this awhile ago and thought it might be helpful to post while we're on this topic....

Apply small dollops of flexible silicone adhesive (red dots shown below) between grill insert plate and grill cover...

And finally, I applied some Dynamat to cargo area floor to eliminate any further vibrations and reduce road noise...

Shown below is a pic of the finished project:

---------------------------------------------------------------------------------------------------------------------------------------------------------------

Here is a list of materials:

2" Foam Pad

1" Speaker Wadding

2" Exhaust Port

Dynamat Extreme

Noico Adhesive Backed Foam Panels

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Summary and Final Thoughts:

Surprisingly, the Harmon Kardon 8" Subs in the Supra are actually very good speakers once you correct some very basic design issues that were overlooked by Toyota... Without ports added, the bass exhaust energy was literally trapped behind the rear panel which created quite of bit of vibrational noise and also muddied bass response...

Adding exhaust ports to the rear panel along with lining the enclosure walls with wadding and insulating the space behind the narrow rear panel, essentially lowered the Q (damping effects) and resulted in a flatter / clearer bass response...The Bass is now deeper, punchier, and far less distorted and eliminated much of the vibrational noise heard...

For anyone considering installing direct replacement subwoofers as a knee-jerk reaction to improving sound distortions, vibrations, and rattles, these basic improvements should be seriously considered before replacing them...

 

[BienLaunchEdition]

I spent a fair amount of time over the past few weeks thinking about how to improve the Supra's subwoofers, which we all know by now, were not designed properly and as a result have issues when it comes to both vibrational noise and lower bass quality...

Some improvement to the bass response can be made by removing the Active Sound Design (faux engine / exhaust noise) which is electrically imposed onto the bass signal when sport mode is selected ...I found that the ASD feature actually "muddies" the bass response and increases distortion and noise...

Also many of us have played with EQ settings in an attempt to optimize sound quality but the OE system still fell somewhat short...

View attachment 24428

With respect to the OE subs I saw a few areas for improvement after seeing a few pics posted of stripped down rear cargo areas and began to get to work...

View attachment 24423

1) I lined both metal sub enclosures (which are indeed separated) with 1" speaker wadding to improve lower bass response and bass quality by reducing distortions created by destructive waves within the metal enclosure..The wadding also serves to increase it's "effective" volume...Speaker wadding turned out to be a very good solution for this...

2) Most of the lower bass vibrational noise and distortion are actually due to the narrow rear cover panel which blocks most of the woofer exhaust energy and introduces most of the nasty low freq vibrations heard...The solution here was to insulate the area within the narrow rear panel with 2" foam leaving the exhaust port open and then add exhaust ports to the narrow rear panel...

View attachment 24426

View attachment 24427

I'm extremely pleased with the results...Bass response is noticeably lower and punchier and vibrational noise is gone...I can now listen to the sound system at 3/4 volume and the bass kicks ass!

Great work.

 

[Ale81]

Nice annotated photos, and a workable solution. Great work and much appreciation to Tadda!

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