How to Improve OE Sub Bass Quality and Eliminate Vibrations

GorillaGuy

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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.
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spta97

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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

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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 :)

50101647076_2feb71f23e_c.jpg
 
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tadda

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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...
 
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GorillaGuy

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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 :)

50101647076_2feb71f23e_c.jpg
It looks awesome! Very professional ??
 

spta97

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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...
For the rest of us who are impatient, for the x-overs, are you just soldering them in line to the woofers?
 
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tadda

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For the rest of us who are impatient, for the x-overs, are you just soldering them in line to the woofers?
I'll probably have connectors added such that I could easily remove the crossover and reconnect the lines if needed....
 

Pratman116

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@tadda thanks so much for the awesome diy - ordered the parts and will be trying it out this weekend! I'm gonna do the speaker covers instead of port/mesh combo :headbang:

How much of an audio difference does the dynamat make? Was thinking about adding it afterwards if I think it still needs more improvement. The equalizer alone made a huge diff!

Lastly, can i just stuff the speaker box area with polyfill? Saw someone on youtube do it and seemed to work.

Thanks!
 
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tadda

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@tadda thanks so much for the awesome diy - ordered the parts and will be trying it out this weekend! I'm gonna do the speaker covers instead of port/mesh combo :headbang:

How much of an audio difference does the dynamat make? Was thinking about adding it afterwards if I think it still needs more improvement. The equalizer alone made a huge diff!

Lastly, can i just stuff the speaker box area with polyfill? Saw someone on youtube do it and seemed to work.

Thanks!
Everything I mention in original post adds to overall improvement...

Do not overfill / overstuff those enclosures with polyfill as you'll reduce brass response and add more vibrational distortion...That person you mention on Youtube who did this I believe had to go back and remove some of the polyfill for this very same reason...Follow my instructions and you won't go wrong...
 

Pratman116

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Everything I mention in original post adds to overall improvement...

Do not overfill / overstuff those enclosures with polyfill as you'll reduce brass response and add more vibrational distortion...That person you mention on Youtube who did this I believe had to go back and remove some of the polyfill for this very same reason...Follow my instructions and you won't go wrong...
Thank you, Sensai Tadda :bow:

Hard to imagine that wadding will unfold into that shape and sit neatly behind a wall where we only have a tiny opening to work from. But I will trust the process!
 
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tadda

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Thank you, Sensai Tadda :bow:

Hard to imagine that foam piece will unfold into that shape and sit neatly behind a wall where we only have a tiny opening to work from. But I will trust the process!
It's batting / wadding used, not foam... And it does require some patience, but it will sit against the floor and walls if done properly...
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