2006 zhp coupe Harmon Karden subwoofer experiment...

[TxCracker2316]

I originally started this little mini project to create some info on the hk factory "subs" as there just isn't much out there on upgrading them, I found out for good reason.
It's subjective as to how good the factory hk stereo sounds, I admit it's not audiophile level but I have to mark it as acceptable for a stock stereo. My hk business cd does send reasonably clear signals at moderate volume levels. I've read it outputs anywhere between 4-6v which takes mid level aftermarket hu to achieve. I'm no audio expert but I do know what I like, clean clear crisp mids and highs are #1, and punchy articulated mid- low balanced bass. Oh and ZERO DISTORTION!
I guess one upside to this all is that I had used things I had already lying around so I didn't spend (much) money overall.
So let's get on to my hair brained, albeit good effort to upgrade the factory subs.
In my self proclaimed genius brain I had planned on making my upgrades in stages.
So here's stage 1.
I had bought a couple new sets of cadence cw kit6 a while back and they have yet to be used so I fgured wth, with those magnets lets go for it.
I'm no stranger to fitting 51/4 and61/2 drivers to factory locations read wrangler 4x6, ford 6x8, and even did 6x9 to the beloved 4x10. So I quickly made templates and adapters.

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Easy enough although it adds considerable bulk in every aspect I made sure to lign up my cut marks so the magnet would fit in the hole where the previous subs went.

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And finished this whole process only took about an hour start to finish.
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Like a glove, excuse the mess in the boot. haha always wanted to say that.
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:fistpump

[TxCracker2316]

So as you can guess I was excited to hear my new earth shattering, sheet metal splitting, glass exploding bass. To my not so surprise, :thumbsdown no gain. Actually degraded sound. So I started thinking. I know my aftermarket speakers needed more juice but it was something more. The bass was sloppy muddy and downright disgusting. I had noticed the little carpet like thing that was between my stock subs and the enclosure and it dawned on me I was getting cross waves from the front and back of the woofer. Well the way the oe speaker mount was designed it sealed well against the front and back waves so I was off on stage 1.1 to improve my Bavarian grade engineering.

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I added some expansion foam and made sure that all surfaces were sealed with my trusty led flash light. I forgot to take a picture after I trimmed all the foam,trust me I didn't install it looking like that.

[ELCID86]

:swiss :applause :respect :fingerscrossed :begging:jealous

and??

[TxCracker2316]

It sounded better for sure but now I needed to improve the power delivery. So here goes stage II.
Not only did I have components laying around I also have an array of subwoofers and amps collecting dust. Does anyone need decent stereo equipment at bargain prices? So I decided to get a line out converter, which I've never used and try installing a small sub and modest mono amp.
What's cool about adding an amp to a bmw is everything is already in the trunk.
So I did some reading on installing the loc and went to work. I originally installed it tapped into the sub wiring and got power but no signal so I tapped into rt frt factory amp out and bada bing signal.
I have a better buy pre made enclosure I had in an exs suv I thought would be a nice upgrade. It's got a painfully small enclosure of less than .5 cu ft but the kicker comp 8" sounded good in her suv so wth. The problem is the woofer was a single channel and the amp is a mono.
The rms of the amp is 500 watts at 2 ohm but rms at 4 ohm is something more like 100. Although that sounds like enough to move the woofer I was getting almost no power to the sub. So my super brain is off churning again.

[TxCracker2316]

Ok so after all this work, I've made no real improvement over the factory hk system. Although I was only planning on just goofing off with all this I did expect improvements. I've pretty much fast forwarded you all to where I'm at now and although I'm not frustrated yet bc I have some experience with bmw just HAVING to be different than any other car as far as engineering went, so I get that part. I'm turning my attention to the loc being the culprit. It's a very cheap example from q power I think, I got from the audio shop we use at work. I Have no experience with these but it's not rocket science to connect. I turned the gain up all the way on it and it seems like the rt channel isn't getting very good signal even after I quadruple checked and re did my wiring. I correctly connected and routed everything else since it's all textbook car audio. I also get that the hk system uses weird resistances and I'm tapping into an amplified signal. But from what I tried to collect is that's what your supposed to do on cheap locs. I'm also using an used amp that I've never used but seems to be in good working order.

[TxCracker2316]

:thumbupI did take out my hk sub enclosure again to wire the drivers bridged 2 ohm to the amp which is kicker btw. I still have the gain like 3/4 up on the amp with only moderate return. It hits hardish on certain songs for what it is but it has like a weird thump rattle like its resonating or bottoming out at higher volumes. I'm pretty disappointed with the overall outcome of this project. I had originally thought I'd have a good example of what could be done without too much time or money invested, which overall I've probably spent 3 hours and $60. But I'm not really ready to run full wires through the car until I get my nav unit. The final stage will be my 15" ssa dcon that's waiting to be broke in with the cadence components in the doors run off an 800w mono and 2 channel Memphis respectively. I'll have the trunk and doors fully dynomat and tuned for sql not spl, like I said balanced not boomy. No reason to beat a car in this condition to pieces, if I wanted to do that I'd have picked an escort. But I know there are bimmer brains (not self proclaimed such as myself) out there that know the answer to my problem.:thumbup

[TxCracker2316]

Ssa dcon.
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Yes that's a bright pink room.

[TxCracker2316]

For fun what else I've been up to getting ready for my in transit wheels!
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[Oli77]

Nice thread! Remind me why a line out converter? I thought these guys reduced signal intensity in order to feed head unit signal to the preamp. Sounds like you set up two amps in series for the bass.

[johnrando]

Interesting, keep us posted.

Sent from my SM-G900V using Tapatalk

[UdubBadger]

Yeah I don't think you'd get the desired result because 1 less surface area for bass to resonate - that's why companies use 6x8s or 6x9s and 2 there's no proper enclosure for it.

I just added an infinity bass link for $160 and called it a day, hits like a right cross from Lennox Lewis now.

[TxCracker2316]

I haven't had a chance to re wire the loc at pre amp yet, been crazy at work. I'll get to it today and update. After football of corse. Go Cowboys!

[ELCID86]

^typo. I'm sure you meant Redskins.


Thumbs, iPhone, Tapatalk.

[TxCracker2316]

No way! I didn't even know there was any Redskins fans left. Lol

[TxCracker2316]

Finally got time to rewire my line converter today. Switched to head unit out LF from amp out LF and all my problems are solved. My sub is hitting hard at 1/4 gain but it's so small it's not moving enough air to hit as low as I'd like. Overall I'm very happy now that I finally got a clean signal to my amp. my little 8" only receiving 100w rms sounds leaps and bounds more clear and harder hitting than stock h/k subs. I'll be getting my final design together for the 15" ported box soon.