Needless to explain why i'm thinking to fix (yes, FIX is the right word choice here) the crappy "premium" Bose system that comes in this luxury 997s car...

Having an extensive experience in acoustic and speaker/sound system design in general, being part of my job, i would like to transform this bad system into decent one without having to change everything or spending a lot $$.

SO...

- The source, the headunit, won't be changed. Anyway, the main problem is not coming from that part anyway.

- The power amp seems to be sufficient. No need to change either, we should be able to work with that, assuming it can withstand 4 ohms load.

- The subwoofer is very bad. We'll see that later and try to fix that as well if needed.


Basically, what's left is the speakers. I would like to work on the doors speakers (4 ?) where it will have the most impact.

First of all, i need to know if everyone on this forum ever had experience with those ? Do you know the sizes/depth ? Do you have pictures ?

I will run a test inside the car with my Real-Time-Analyzer and pink noise to see how bad that is, but to my ear the problem comes essentially with the lack of midrange.

Any help/input would be very appreciated. Will try to post pictures and information about everything we find..

 

In changing out the head unit to an aftermarket Pioneer nav and bypassing the Bose main amp transformed the sound completely and for the better.

I ended up utilizing all the Bose speakers sub amp and subs.

Good luck

 

This is so interesting... Jon8 is changing out all the speakers, and leaving the other components intact. But Socalsteve changed out everything BUT the speakers.

I'd be really interested to know how things turn out, Jon.

 

I did both. I change the head unit, speakers and 6 disc changer in my 06/997 cabriolet. I went with a Kenwood 8120 touch screen with Garmin navigation. Added Focal speakers and went with an Alpine amplifier. The only thing I left stock was the subwoofer. I liked the stock sub cause it offers leg room for the passenger. In addition, I went with real time navigation and placed the hockey-puck nav unit under the speaker grill located in the center of my dashboard. The system offers everything I was looking for....bluetooth, Ipod, USB connection in the glovebox and XM radio. Sounds great and looks stock because I had a custom fascia made to match the factory gray fascia.

 

I can't trust the speakers.

The sonic signature of these shows (deep) flaws that cannot be compensate by any EQ, amplifier or source.

Don't get me wrong: i'm not saying the amp/source cannot be improved (they can) but the bottleneck is the speakers (transducers).

Regarding the subwoofer, i believe it's a bandpass enclosure 6th order, anybody correct me if i'm wrong. If you have any information regarding sub's transducer or else please let me know i don't really want to get everything apart..

 

Ok, here's the deal. It's a loud, small car. Whatever you do is going
to be a total waste of time and money. It will never sound good while you are driving.

Dump the stupid outdated head unit and get a nice double din touchscreen with whatever extras you want...xm, iPod, etc...

Good luck,

Steve

ps:if all you care about is sitting in your garage without the engine running, then replace everything...

 

Focal K2 Power 100KRS + Focal Utopia Be® 13 WS should fit. i saw an article on avsforum, i think, about such a project. search for it, should be easy to find.

 

Ok well i have to agree with Jon8 somewhat.
I changed my head unit to the latest Pioneer Avic-z110bt and left everything else stock.
I would not , in a million years have stayed with the stock head unit in my 07 C4S Cab.
So now i have a good nav with a beautiful screen that offers me ipod integration , bluetooth, traffic info and all the extra goodies.
But here's where my problem comes in.
The sound still sucks!
Now to me sound is very important and honestly it's pretty bad even with the new head unit.
So my installer is recommending i get either a 4 channel or 6 channel amp and run the speakers through that instead of the Pioneer amp. Bose sub would stay in powered by the original amp.
He's telling me that it would definitely improve the sound.
At this point i really don't know what to do. My car is a lease so i don't want to drop thousands of $$$ but i have to find a way to improve the sound...

 

The best audio upgrade would be... straight pipes, 2 windows down and a very very long tunnel

 

Ok i've spent an hours in my garage doing sound tests on the car tonight.

I used pro equipment: industrial 1/3 octave RTA with 2 different calibrated mic (one for SPL and the other for frequency response). I could have use higher resolution RTA (such 1/24 oct) but the problems are big enough, no need for a microscope, trust me...

Quick diagnosis: Ugly.


I'll be honest: i wasnt expecting the kind of flat frequency response i have in my home. Neither i want a concert hall in my P car. All i need is something decent. I'll let the car audio aficionados out there put 5k or 10k or gears in that (noisy) car...
Personally i would rather listen to the flat 6 and aftermarket exhaust sound, for most of the time i'm enjoying this car.
Being that said, i still want to listen music (weekdays traffic, highway long trip, etc..)

Ok here's the good news: There is plenty of power (for OE system). I've hit 98 db on a pink noise (no bass peak here) without pushing too far the ****... I'm pretty sure it's possible to work something out with the actual power amp.

That's pretty much it for the good news.

Subwoofer: i don't know much about it, but it looks like a tiny over-exploited 6-inches transducer with bandpass (4th or 6th order) config enclosure.
Oups sorry guys, i'll translate: it's like a 3-cylinder motor with a small turbo pushed with the max Psi possible..

Subwoofer for dummies: a bandpass enclosure is always restrained to certain frequencies. In that case, i guessed 40-50hz and i was right, i measured an hefty peak at 40-50hz. Mostly shifted to 50hz. And that makes sense: Bose (and Porsche) probably needed to impress the customers and 40-50hz is very good frequency range to do so. It sounds ''powerful'' while not space (enclosure requirements) and power consuming like 20-35hz subwoofer can be, but not ''thin sounding'' like a peaky 60-70hz sub could be.

So, in a marketing point of view, that was smart.

Problem is (regarding overall bass response):

While the peak in the 40-50hz range is huge (and unavoidable -read below-) there is a major lack of midbass (low-midrange) especially in the ''Barry White & snappy kick drum'' frequencies 125-315hz, which makes the contrast horrible.
We're not talking about snobish audiophile tiny flaws here, we're talking about a +/- differencial of more than 20-30db (every 3db step is double when measured and every 10db is double to the human ear perception).

Ok what all that means ?

It means the speaker's overall design/system is basically defective. The conception is defective.

But, hey!, we have Treble/Bass adjustement, right ? We will be good.

Wrong. The peaky 40-50hz STAYS even at -9 bass correction while making the midbass even worst. You want more 100-300hz ? The bass correction barely helps and makes the peaky sub sounds horrible.

I've measured the system FLAT (0 bass 0 treble) and without surround CDS. besides the subwoofer peak and midbass dip problem, the highs seriously falls after 8khz (a good sound system should cover at least 18-20khz). The treble correction helps a little, while giving a boost in the 8khz-15khz range. But the sonic caracteristics of the med-high transducers are obviously not comfortable with too much correction (harsh sound) and it makes the lack of midbass even more obvious (and we absolutely don't want that).

I'm sorry, i'm not done with the bad news.

To get things even more complicated, the frequencies response balance change... with the volume.
That's normal with active amplified speaker system (and even on passive) but that much ? It's unacceptable, to say the least. I don't know how many amp's channels there is, but it's badly balanced. The overall speaker's sensitivity/outputs are mismatched (but it makes me think the system was built with the convertibles in mind -a lot of bass...tuned for high volume-)

What that change in your life ? That means if you listen it very loud, the peaky sub won't follow the now-very-loud-mid-highs. And if you listen at low or moderate levels, the sub will be too loud or the mid-highs won't be loud enough (depends of your point of view..)

Problem is: it makes the Treble/Bass adjustements very difficult, and only good for certain SPL (sound pressure level).

Next week guys, we will add another complication to all that mess: we will measure the in-cabin noise while running the car! I'm already expecting a very conflictual low-mid noise pollution against an already anemic low-mid sound reproduction system!

I'm motivated to find a solution, so i'll work hard on that in the next weeks...

 

No highs? No Lows? It must be Bose!

 

A true but sad commentary on Bose.
Reus audio (www.reusaudio.com) keeps the head unit but replaces everything else. It appears they do extensive sound testing for each application. They are not cheap. But you're still stuck with the less the state of the art head/nav/bluetooth/ipod interface unit.

 

Not a tough concept...the Bose system only works when paired together. If you change one thing about it then it sucks. You want new technology (ipod, nav, xm) then change everything. I went with the Kenwood 8120, Alpine amp, and Focal speakers. I drive a cabriolet and it sounds great. Love the touch screen and it looks factory. review.zdnet.com/.../kenwood...8120/32892345 -

 

Jon, I am not surprised about your results and will look forward to your solutions and results.

I replaced the whole shabang in my 996 with an Alpine front-end, amp and focal 3-way speakers (with a small sub behind the seat) but feel like I'm "stuck" with the Bose in my '08 997. Try as I can, I am unable to bring forth any significant midrange to speak of and do not want to spend thousands on a total redo.

 

agreed!!!!