How to Improve OE Sub Bass Quality and Eliminate Vibrations

[tadda]

Id be curious to see how they compared with theses Pioneers.

I understand the OEM subs were specifically designed for the space and type of enclosures that are in the car. But they just seemed really cheap and flimsy. Like they wouldn’t withstand the extra power from adding an additional amplifier. The subs weighed barely anything, the cone material seemed extremely cheap, and the size/weight of the magnets was laughable.

Once you resolve all the other design enclosure issues that I outline in the first post the HK sub's actually sound pretty decent and will handle quite a bit of power...What I've learned over the many many years of doing this (yeah I'm old...ha!) is that the quality of performance isn't necessarily measured by weight or magnet size...They might not be pretty but I assure you the HK woofers are robust and are built surprisingly well...

One of the issues is that the current subs are being tasked to handle far too much range / bandwidth...With some of my past test analysis I've done it showed that the operating range of the OE subs is fairly wide 50~500hz... Like I mentioned earlier by simply adding 12db 8 ohm high-pass cutoffs (150~200hz) to the current OE subs (making them mid-bass) will free up more OE amp power and also allow the OE "midbass" woofers to operate far more efficiently...Then add a line converter and powered subwoofer (<200hz) and your done...Shouldn't cost any more than $800...I'm currently considering the JL Audio 400W powered 10" sub...

Finally, yeah, I could spend thousands on upgrading the system, but there quickly reaches a point of diminishing returns and as a Engineer the fun is also doing the work myself and finding pragmatic simple solutions to problems...Been down this rabbit hole far too many times in my younger days...I have to still remind myself that the weakest link in any audio system is the human ear...ha!

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[spta97]

Hey Everybody,

I just wanted to share with everyone what I did to improve the bass in my MkV. Its not meant do be a DIY, just some pics and info on what I used and a brief description on how I did it.

Awesome job! You should totally make a separate thread.

I love how how you used lexan/plexiglass for the amp mount. On my X3MC I used sheet metal - wish I had thought of the plastic route

 

[spta97]

That said, I've always said that installing a dedicated amplified sub to the system, high pass crossovers to the existing HK woofers @ ~200hz (utilizing them as mid-bass woofers) would be the best low cost / high quality solution for the existing system...This would also effectively increase headroom of the HK OE amp as well since power below 200hz would no longer necessarily be drawn from the OE Amp...

This is my next step and will create a new thread when completed...

I got passive crossovers for the HK "woofers" on my X3M but never installed them. I am looking forward to the writeup to see how you integrate as I wasn't crazy about cutting the wires to the connectors. 200hz seems a bit high, I like to keep my subs 80hz and below but that is all personal taste.

One of the issues is that the current subs are being tasked to handle far too much range / bandwidth...With some of my past test analysis I've done it showed that the operating range of the OE subs is fairly wide 50~500hz... Like I mentioned earlier by simply adding 12db 8 ohm high-pass cutoffs (150~200hz) to the current OE subs (making them mid-bass) will free up more OE amp power and also allow the OE "midbass" woofers to operate far more efficiently...Then add a line converter and powered subwoofer (<200hz) and your done...Shouldn't cost any more than $800...I'm currently considering the JL Audio 400W powered 10" sub...

If this is the sub you are referencing, the dimensions are 18.5"W x 11.125"H x 5"D.

In what orientation would you place it? Flat on it's back or stood up behind the HK woofers?

Trying to convince my gf to get a powered sub but she needs the space for groceries and Costco runs

I wish they made a powerful small sub which could be tucked away in one of the corners behind the taillights.

My X3 has 75% of the truck taken up by my JL Audio bandpass box with a 10" W7.

My formula Bass > Space

 

[tadda]

If this is the sub you are referencing, the dimensions are 18.5"W x 11.125"H x 5"D.

In what orientation would you place it? Flat on it's back or stood up behind the HK woofers?

Trying to convince my gf to get a powered sub but she needs the space for groceries and Costco runs

I wish they made a powerful small sub which could be tucked away in one of the corners behind the taillights.

My X3 has 75% of the truck taken up by my JL Audio bandpass box with a 10" W7.

My formula Bass > Space

I plan to lay it flat and close to the rear...Looking from the back with hatch open I would also have it such that the side controls would be on left side closer to the Amp wiring....I wouldn't place it forward as I would not want to block the OE woofer exhaust ports...

It's only 5" high so really won't take up a whole lot of space and I'm not concerned with placing groceries on top sides and around the sub...I also not that big a power shopper...ha!

 

[spta97]

I plan to lay it flat and close to the rear...Looking from the back with hatch open I would also have it such that the side controls would be on left side closer to the Amp wiring....I wouldn't place it forward as I would not want to block the OE woofer exhaust ports...

It's only 5" high so really won't take up a whole lot of space...

This hatch is so tiny I think anything is too much lol.

I was reading reviews on the JL and some people noted it was overpriced for what it was and not up to JL quality.

Curious what you end up with/how it works out - will be waiting patiently for the thread!

 

[tadda]

This hatch is so tiny I think anything is too much lol.

I was reading reviews on the JL and some people noted it was overpriced for what it was and not up to JL quality.

Curious what you end up with/how it works out - will be waiting patiently for the thread!

The hatch it large enough for me with the box in it...And yeah, I saw a few negative
reviews as is the case with most reviews....Far more positive than the few negative comments though...I'm looking for tight deep base not a ghetto boomer...ha!

 

[spta97]

The hatch it large enough for me with the box in it...And yeah, I saw a few negative
reviews as is the case with most reviews....Far more positive than the few negative comments though...I'm looking for tight deep base not a ghetto boomer...ha!

 

[tadda]

I got passive crossovers for the HK "woofers" on my X3M but never installed them. I am looking forward to the writeup to see how you integrate as I wasn't crazy about cutting the wires to the connectors. 200hz seems a bit high, I like to keep my subs 80hz and below but that is all personal taste.

Oh, I forgot to reply to this...

My reasoning for adding 200hz high pass crossovers is more about freeing up OE HK amp headroom and taking full advantage of the powered sub operating range...I want to dedicate the existing HK woofers strictly for upper-mid bass (200~500hz) operating range...As is, I think those HK OE woofers are operating over far too broad a range...

I see many folks are adding powered subs to their systems and not taking advantage of the fact that at least 1/4 of the power consumption of the HK OE amp is actually being used below 200hz...So, if you are going to install a powered sub in which it's range / capability is from say 50~200hz, then use it, and at the same time free up at the very least 1/4 of the power consumption of the existing OE amp...This is a for more efficient use of available power which should in turn result in a less distorted system sound output at higher power levels...

 

[GorillaGuy]

One of the issues is that the current subs are being tasked to handle far too much range / bandwidth...With some of my past test analysis I've done it showed that the operating range of the OE subs is fairly wide 50~500hz... Like I mentioned earlier by simply adding 12db 8 ohm high-pass cutoffs (150~200hz) to the current OE subs (making them mid-bass) will free up more OE amp power and also allow the OE "midbass" woofers to operate far more efficiently...Then add a line converter and powered subwoofer (<200hz) and your done...Shouldn't cost any more than $800...I'm currently considering the JL Audio 400W powered 10" sub...

I agree the OEM subs are tasked with too high of a frequency range. I think this is what causes some of that weird distortion at lower to medium volume levels. Two dedicated 8" mid-bass woofers and one 10" low range woofer would definitely sharpen the overall sound of this system. It would have been awesome if they had made one woofer an 8" (mid-bass) and one a 10" (<120hz) to handle bass duties.

I have a 10" JL Audio W3v3 in the H.O. Wedge box I used in my previous car (Genesis G70), and it sounds phenomenal. I dont have any use for it at the moment but dont want to get rid of it because I love it so much. JL makes awesome products.

 

[GorillaGuy]

Awesome job! You should totally make a separate thread.

I love how how you used lexan/plexiglass for the amp mount. On my X3MC I used sheet metal - wish I had thought of the plastic route

Thanks!
I covered the back side of it with sound deadening material as well for good measure. I definitely didnt want that rattling or making any unwanted noise after putting everything back together.

 

[GorillaGuy]

This hatch is so tiny I think anything is too much lol.

Same here! I dont do much shopping either, but if I throw my gym bag and a backpack back there, there's not much room for anything else haha.

 

[spta97]

Oh, I forgot to reply to this...

My reasoning for adding 200hz high pass crossovers is more about freeing up OE HK amp headroom and taking full advantage of the powered sub operating range...I want to dedicate the existing HK woofers strictly for upper-mid bass (200~500hz) operating range...As is, I think those HK OE woofers are operating over far too broad a range...

I see many folks are adding powered subs to their systems and not taking advantage of the fact that at least 1/4 of the power consumption of the HK OE amp is actually being used below 200hz...So, if you are going to install a powered sub in which it's range / capability is from say 50~200hz, then use it, and at the same time free up at the very least 1/4 of the power consumption of the existing OE amp...This is a for more efficient use of available power which should in turn result in a less distorted system sound output at higher power levels...

Makes perfect sense. The only concern I have with a x-over that high is it can muddy the sub and cause the sub amp to work harder reproducing mid-bass.

From your posts, I'm sure you will tweak it to perfection

 

[spta97]

Thanks!
I covered the back side of it with sound deadening material as well for good measure. I definitely didnt want that rattling or making any unwanted noise after putting everything back together.

Great idea. I don't know why I didn't think of this with mine! I've used plexiglass to make tabs for non-standard speakers to fit in the door in my previous 2005 E46 M3 (in fairness, my memory from 15 years ago isn't great lol).

At the risk of violating a forum rule, here is what I made out of welding plate for my X3MC (shares the same HK amp and woofers as the Supra).

I painted it and put that door edge guard around it due to sharp edges. Took a while burning through my RotoZip metal blades until I busted out the angle grinder

 

[tadda]

Makes perfect sense. The only concern I have with a x-over that high is it can muddy the sub and cause the sub amp to work harder reproducing mid-bass.

From your posts, I'm sure you will tweak it to perfection

Subs get "muddied" if the input signal to the subs' amp is clipped, exceeds it's input threshold voltage, or the sub's amp itself gets maxed out...The JL sub is very capable of handling <200hz with no added bass distortions....Yeah, no doubt this will require some tweaking...Always does!

Either way, I would not add an external amplified sub with adding a high pass crossover to the existing HK woofers as the overlap in low frequencies would most likely create the muddy response we're trying to avoid here...

I'll start another thread on this soon...

 

[GorillaGuy]

I painted it and put that door edge guard around it due to sharp edges. Took a while burning through my RotoZip metal blades until I busted out the angle grinder

It looks awesome! Very professional ??

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