Woofer Upgrade Project

[poss]

I have the Bavsound upgrade to the Harmon Kardon speakers in my E46 M3 'vert, plus a 10" compact subwoofer I managed to retrofit into the ski-pass (which really brings it all to life).

My zed has the top of the line DSP 10 speaker system, but the bottom end in particular leaves a lot to be desired compared to the modified sound system in my M3 'vert - problem is that there's nowhere practical to put a 10" or larger sub so I am limited to replacing the existing 6.5" subs/woofers.

I eventually settled on the 6.5" CT Sounds Tropo for rear sub replacement and 6.75 Kicker for footwell woofer replacement - 4 small subwoofers instead of one large one. The question is: how well will this work? These were the largest subs I could find that could reasonably fit without major modifications and that could match the impedance of the existing speakers (and thus could work with the factory amp). Both speakers are dual 4 ohm voice coils - which can be run in parallel to match the factory footwell speaker impedance of 2 ohms, or in series to match the factory sub impedance of 8 ohms.



The CT Sounds sub is a very tight fit, and required grinding out of the existing mounting hole by a mmm or two, as well as cutting off the unnecessary rubber 'waistband' around the magnet - but fit it does!



Next step is to create a custom adapter to get the Kickers mounted in the footwell. I've decided to make them out of marine-grade plywood.

 

[poss]

Update:

Fully-installed one CT Sounds 6.5" sub and jury-rigged one Kicker 6.75" for an initial listening test.

The Kicker is a quantum leap over the factory 'premium' woofer, and so is the CT Sounds sub over the factory sub. All one has to do is touch the cones - you can easily feel (and see) the difference. Both subs are super tight and moving substantially more air - so much so you now get a seat massage to boot out of the rear sub.

Looking forward to replacing the other two factory woofers - BTW the factory subs are up for sale if anyone's interested

 

[poss]

Made the footwell speaker adapter for the Kicker today out of 12mm marine ply. 143mm diameter hole (UPDATE: 143mm is recommended by Kicker doco, but you can prob. go as small as 135mm - which means the screw holes aren't as close to the edge). 20mm 8G woodscrews to mount the kicker. The original speaker screws need 5.5mm recessed holes (unfortunately they overlap with the kicker mounting holes and the original screws are not long enough for 12mm ply anyway - need 6mm recessing)

 

[poss]

Footwell bracket test fitting -looks good!

 

[grannyknot]

I have to replace a blown woofer in the spring when she comes out of storage, I had a look at the CT Sounds 6.5", that's a very reasonable price.

 

[poss]

Please note that the CT Sounds 6.5" is not a viable footwell woofer replacement as it is too deep - for the passenger side at least (it's only viable as a sub replacement behind the seats). The Kicker is the best (and only) viable option I have found for the footwells that ticks all the boxes.

 

[poss]

The footwell speaker on the driver's side is mounted on a plastic riser (presumably as the driver's side trim is substantially deeper than the passenger side (on a RHD anyway).

Unfortunately, this plastic riser also has a shroud (presumably to help direct the sound out of the trim hole? or perhaps simply put there to annoy me!), and this has to come off to fit the slightly larger diameter of the Kicker - I used a Dremel and cutting blade as my weapon of choice:



Smoothed it off with an orbital sander and 80 grit - then test fitted my painted plywood adapter for the Kicker - Perfect fit!

 

[dj_jormi]

Amazing, thanks, i try!!!

 

[poss]

Footwell Kickers installed! I used some adhesive foam strip on the back of the adapter to make a good seal. These are a big improvement over the factory footwell drivers - I have the 80hz boost maxed out on the DSP and they sound fine, whereas the original speakers sounded like mud with the bass boosted:

 

[poss]

PS: These footwell subs also give you a foot massage

 

[jmilt13]

I am in the middle of a very similar upgrade. I chose the Skar 6.5" sub with dual 4ohm voice coils for the subwoofer replacement. Appears to fit the frame without modification, just need to drill holes. I am also adding a 80hz crossover inline for each sub.

https://www.skaraudio.com/products/evl-65-inch-car-subwoofer

The footwell speakers are just plain woofers though? Why did you choose to use subwoofers?

 

[poss]

The footwell speakers are just plain woofers though? Why did you choose to use subwoofers?

Why did you?

That will save a lot of time if the speaker mounting rim can be made to match up with the existing mounts!

80hz high pass or low pass crossover? I assume low pass...

Do you know where the midrange door speaker crossover point is? Regardless, I doubt that the door speaker would get anywhere near 80Hz - so you may create a dip in the freq. response. I'd leave the crossover out unless you find the speaker intrudes unwelcomingly into the midrange (mine don't). Passive low freq low pass xovers also usually use magnets that colour the sound.

I design and build sound systems and set my sub xover point as high as possible (200-250 kHz) as they can handle mid-lows better than a midrange woofer and the mid woofer will sound heaps cleaner if it isn't struggling to produce the lows.

 

[jmilt13]

The footwell speakers are just plain woofers though? Why did you choose to use subwoofers?

Why did you?

That will save a lot of time if the speaker mounting rim can be made to match up with the existing mounts!

80hz high pass or low pass crossover? I assume low pass...

Do you know where the midrange door speaker crossover point is? Regardless, I doubt that the door speaker would get anywhere near 80Hz - so you may create a dip in the freq. response. I'd leave the crossover out unless you find the speaker intrudes unwelcomingly into the midrange (mine don't). Passive low freq low pass xovers also usually use magnets that colour the sound.

I design and build sound systems and set my sub xover point as high as possible (200-250 kHz) as they can handle mid-lows better than a midrange woofer and the mid woofer will sound heaps cleaner if it isn't struggling to produce the lows.

I haven't attempted to change out the footwell woofers. Just doing the subwoofers behind each seat, crossover is for them. Low pass 80z.

I think we have opposite opinions on subwoofer frequency use. I try to cut them off as steeply as possibly around 80hz. In this case a 2nd order (12db) crossover. (Which uses and inductor, not a magnet) I find this keeps them tighter. I suspect the stock carver amp/dsp is sending way to high of frequencies to the subs. For what it's worth, I've designed hifi loudspeakers from scratch, including my own crossover designs.

I'm restoring the entire interior, so I won't have a good answer to if this is successful for a couple months.
Cheers

 

[poss]

I haven't attempted to change out the footwell woofers. Just doing the subwoofers behind each seat, crossover is for them. Low pass 80z.

Apologies, Misunderstood. Thought you were doing footwell speakers.

To answer your original Q - I put subs in the footwells because I guessed (given my experience in sound system design and construction) that simply upgrading the 6.5" behind seat subs with very-long-throw subs (perhaps even longer throw than the SKAs you are installing?) would not be enough to give decent bottom-end - particularly with roof down.

In my mind my decision is now vindicated. An excellent choice! The footwell Kickers do not intrude into the upper midrange but cover low midrange better than originals + reinforce lows, and the CT Sounds subs certainly don't require an additional low-pass filter.

 

[jmilt13]

Good information, I will try it with and without the low pass crossover. Cheers

 

[B21]

I did a similar project on my 20i E89, woofer wise..did the same trick with the plywood..I bonded and screwed mine in, used Fosgate Punch 6.5" woofers..with a bigger DSP amp worked well!

 

[Tom2207]

I thought sub was usually 80hz and down , usually stopping by 20 hz , unless your one of the '' turn it down to 11 '' brigade , [in a Spinal Tap esque sort of accent] . If im using x overs Im a multi amp system Ive been known to use a gentle slope LR or Butter 6db/oct and spend a bit of time aligning the overlap and at the 100hz spot you can have extra air moving for free . But then again I like to x horns over higher than normal and avoid the 1.6 nasties too. Well at least that was the way till line array became very affordable , even though its not the golden bullet its claimed to be at all. Horses for courses.

 

[poss]

I thought sub was usually 80hz and down

Sure. If you have a 5.1/7.1 channel system the sub channel is usually limited to around this range, for example. 80-100 Hz is a common sub crossover range when you also have a decent midrange woofer - usually sized around 5.5 - 6.5", which typically start to tail off dramatically at around 100Hz and reach their absolute limit at around 60Hz.

For music you really want a subwoofer that can perform relatively linearly down to around 45Hz to reasonably accurately reproduce the low sound that, say, a kick drum puts out. My 12" Peerless extra-long throw subwoofers do this range but tail off at around 40Hz. If you want earth shaking for movies you're talking even lower frequencies and even bigger subwoofers (or ones with stacked voice coils and serious excursion).

But just because a speaker is a 'sub' doesn't mean it can't do higher frequencies well too. For example, my 12" Peerless 'subs' also do as good or a better job in the 80-200Hz range than my expensive Danish Scanspeak 5" mid-woofers - so that's where my lower xover point is. The mids sound cleaner as a result. I also set my tweeter xover point as low as possible (1.5kHz instead of 2-2.5kHz) because it simply reproduces this frequency range far better than the mid-woofer. I use a linear phase digital xover and can easily adjust the xover points to do listening tests.

The Zed only has room for 6.5" subwoofers without serious modification. Even the new and quite good CT Sounds I fitted tail off around 57Hz and the Kickers at 62Hz. The factory subs probably aren't even this good (they only move at best around half the air of the CT Sounds), and the factory footwell speaker, it is receiving a full low frequency signal that it has absolutely no hope of reproducing and that's why it sounds like mud. The Kickers, on the other hand not only do a better job of reproducing the effective range of the factory footwell speakers, they also do a far better job of handling the lows, and add reinforcement to the 6.5" subs behind the seats.

Even with 4 subs I still have to significantly boost the 80hz band on the DSP to get a good bass and drum sound. With the roof down I put the bottom end boost to nearly full bore - but the new subs handle this no problem.

 

[Tom2207]

I thought sub was usually 80hz and down

Sure. If you have a 5.1/7.1 channel system the sub channel is usually limited to around this range, for example. 80-100 Hz is a common sub crossover range when you also have a decent midrange woofer - usually sized around 5.5 - 6.5", which typically start to tail off dramatically at around 100Hz and reach their absolute limit at around 60Hz.

For music you really want a subwoofer that can perform relatively linearly down to around 45Hz to reasonably accurately reproduce the low sound that, say, a kick drum puts out. My 12" Peerless extra-long throw subwoofers do this range but tail off at around 40Hz. If you want earth shaking for movies you're talking even lower frequencies and even bigger subwoofers (or ones with stacked voice coils and serious excursion).

But just because a speaker is a 'sub' doesn't mean it can't do higher frequencies well too. For example, my 12" Peerless 'subs' also do as good or a better job in the 80-200Hz range than my expensive Danish Scanspeak 5" mid-woofers - so that's where my lower xover point is. The mids sound cleaner as a result. I also set my tweeter xover point as low as possible (1.5kHz instead of 2-2.5kHz) because it simply reproduces this frequency range far better than the mid-woofer. I use a linear phase digital xover and can easily adjust the xover points to do listening tests.

The Zed only has room for 6.5" subwoofers without serious modification. Even the new and quite good CT Sounds I fitted tail off around 57Hz and the Kickers at 62Hz. The factory subs probably aren't even this good (they only move at best around half the air of the CT Sounds), and the factory footwell speaker, it is receiving a full low frequency signal that it has absolutely no hope of reproducing and that's why it sounds like mud. The Kickers, on the other hand not only do a better job of reproducing the effective range of the factory footwell speakers, they also do a far better job of handling the lows, and add reinforcement to the 6.5" subs behind the seats.

Even with 4 subs I still have to significantly boost the 80hz band on the DSP to get a good bass and drum sound. With the roof down I put the bottom end boost to nearly full bore - but the new subs handle this no problem.

Yep its not easy when your used to running 21 inch subs , anything else is a compromise ,, I used to run line7 servodrives , but they wouldnt fit in a car , they hardly fit in a lorry , but then again you dont need many.

 

[poss]

I installed the second CT Sounds sub behind the passenger seat today, and was surprised at the amount of improvement made by replacing the remaining factory sub. I had to turn the 80Hz bass boost on the DSP way down from where I had it to only a couple of notches. With the top up no EQ is required at all - and with the Bavsounds and Kickers I mean no EQ whatsoever across the spectrum - gotta be pleased with that!

These CT Sounds subs are impressive! (particularly given the price)

I highly recommend doing the lot, as tightening up the bottom end really shows up how horrible the factory tweeters sound.