Slicky rick, I missed something DRC said earlier - he indicated that he's put the factory unit on an oscilliscope and observed what looks like an integrated crossover. If this is indeed the case, what he suggests is not at all a bad idea, but I'd be skeptical of it sounding terribly good unless the specific speakers you picked are a pretty good frequency band match to the OEM ones.

If there is not some sort of OEM crossover, relying on a small cap to protect your tweeter will sound disastrous.

I'd reserve judgement until I actually heard OP's setup, but it isn't what I would do without having heard it in person first.

 

Okay, let me just settle this one.

The Bose amp signal to the mids/tweets is combined (shared). It is actively high-passed already and there is some EQ as well. The stock midrange is therefore electronically high-passed only (no low-pass). It is easily measurable with a laptop and a sound card, and this is what Del Rey Customs is referring to. The stock tweeter has a built-in capacitor, which acts as an additional passive high-pass filter ("1st order, 6db/oct) that combines with the electronic high-pass to give your summed high-pass filter.

If you replace the stock tweeter with an aftermarket and you DON'T add a capacitor, then you probably won't blow the tweeter because of the electronic high-pass from the Bose amp. However, the electronic high-pass is at a relatively low frequency, so depending on the tweeter, you can damage it over time, or at the very least, you're feeding it frequency signals that it sounds terrible reproducing (such as the resonance frequency).

In plain language:
- if you replace the tweeter and don't add a capacitor, it'll probably still work and it'll probably sound better than the OEM
- if you measure the frequency response of your midrange, and purposefully add a capacitor value that permits a smooth transition and preferably suppresses the resonance frequency, it'll sound even better. If somebody is bored, this might be a fun project.

 

Great post gasongasoff!

The point I was trying to make is that simply using a capacitor and not a proper crossover to separate tweeter from mids is very sub-optimal. A proper crossover will work much better, and a basic one is dirt cheap.

 

And the built in one is even cheaper still. Gas hit it on the head. That is why op's system might really have a chance of sounding better as the integration speakers of focal do indeed have built in caps to allow simple oem integration

 

There is no such thing as a high pass filter even cheaper than just a capacitor.

Even $50 Infinity speakers from Best Buy come with a more sophisticated crossover.

 

I was referring to the fact that our bose sytems have internal crossovers already, as gas so aptly mentioned, and that we dont have to pay a single cent for them, my secretasian friend.
Im really glad for this topic as we are getting to deatils with the crappy sound sysytem

 

Love the traction and interest this thread is getting. Hope to learn from you guys too. Note the cap used in the stock tweeter and the cap used in the Focal Integration tweeter. I didn't check the farads, but I suspected they were close. I didn't add a pic of the 6.5" woofer, but it had its own low pass filter integrated into the woofer. I don't recall perfectly, but I believe the stock Bose 8" had a low pass cap in it as well.


Note the "fancy" crossover integrated into the back of the 100CVX 4" coax. I wouldn't want to take this apart, because the integral solution is clearly a well designed one.



Note the comparison of the size of the 4" coax to the rear panel size. The Bose rear speakers are a 3" component set, making a 4" speaker a tough fit into the location.

 

Going back a little while, gasongasoff questioned my love of the 6.5" woofer instead of using an 8". Well, I've learned that was certainly a fair call. I think my friends using IS200's with 8" woofers are probably going to have better results. I should have chosen it as well, but I was the guinea pig! Live and learn.

I didn't realize how much the system was relying on the stock sub until I pulled it out. It relies on it way too much in my opinion. I listened to the system without the sub and it was missing more than the bottom octave, it was missing several of the bottom octaves! The Bose has decent punch and is covering pretty well and the Focal 6.5" woofers are doing a good job with the midbass, so the system is still performing very well. So what to do? Running 8's in the doors should help. What next?

I pulled the sub out to stuff it, as others have done. I didn't just shove stuffing into the ports, I took it apart. Info for fellow, DIY'ers, the unit has 2 5.25" drivers and a 100W amp. Most of us know how worthless power ratings can be, but I know that's what the power is because Bose stamped it on the unit! Frankly, I can't imagine it producing 100W.

Anyway, put it back together and auditioned. Honestly, it seems a bit tighter and better defined, but if I had to A/B one stuffed and one not stuffed, I'm not sure I could tell the difference. Maybe the difference is more than I realize, but it is certainly not night and day.

So, what to do? Most go with 2 8" subs in a box with a dedicated amp. There are boxes that will fit well in the space too. The line in is available right there, but that won't work for a dedicated box, then you need to wire another amp in the frunk and run power to it. This is going too far for me. I just don't want to add another amp and take up frunk space.

2 alternatives I'm considering. A flat 8" powered subwoofer like the Sound Ordinance or Focal. They are about 14"x8"x3", so they would easily lay on the rear shelf. Simply use the Bose power and line feed that are right there. After taking the Bose box apart, I had another idea, replace the drivers in the box. JL Audio makes a 5.25" component woofer, but it only goes down to 48hz I think. JL Audio also makes a 6.5" sub woofer, but will it fit? Pros and cons:

Powered low profile:

Pros

• Good 8" sub with decent kick
• Should easily drop in to the location with no work.
• Tunable for volume and crossover - a huge plus.
• Cost, Sound Ordinance only about $150 (Focal much more at $300)

Cons

• Power feed may not be adequate (need to understand how to check)
• Aftermarket add on, obviously looks out of place.
• May not have that much power, certainly will not equal twin 8"

Driver swap into the Bose

Pros

• Totally stealth
• Stock box is pretty well made and secure
• Super easy installation

Cons

• 5.25" JL Audio drivers are only woofers and not really subs
• Drivers cost $159 each I believe (need to check if that is for a pair)
• 6.5" drivers also cost $159 each and may be difficult to install.
• "100W" Bose amp may not be adequate to power them

So, what to do? Suggestions? Thoughts? The system sounds quite good as is, but I'm already thinking about how to finish it off.

 

Whatever your opinion is, I think we can all agree we should thank RyeM3 for leading the charge and experimenting here.

IMHO a 5.25" driver that isn't intended to be used as a sub will not yield decent results in the OEM enclosure. The driver just wouldn't be designed for it. Does the stock enclosure look like it could be modded to carry a bigger driver? I am a big fan of the OEM look.

 

Thanks much. Not sure about modding the enclosure, didn't study it. It's funny that the woofer was listed under subs, but doesn't seem to be a pure sub driver. OTTH, the 6.5" drivers are clearly pure sub drivers. Concern there might be that they ARE pure subs and the system seems to need more than just the bottom octave.
I'm really thinking the flat sub will provide the best sounding solution, but adding new drivers would clearly be the easiest and most OEM. Could always experiment with the 5.25"ers and if they don't work, just return them. The inside of the box is actually pretty tight, especially where the ports are located - they are pretty close to the stock magnets (the ports have 4" tubes extending into the box).

 

go go go go brother.

 

I'm completely amazed, my Porsche Bose sound system is the best I have ever heard, so for me is not an issue to make any upgrade, or do you have enough time or money, any way great thread

 

The stock is good, but for a few who are somewhat audiophiles tend to need a little something better. We work on the upgrade so labor is $0.00.

As for time, you know what they say.... "Is it not amazing that people who complaint about not having time always find time to complaint?" My point is that we make time for our passion.

Cheers!

 

Glad to hear it. Without at all intending to be crass, I see MANY people listening to music using white ipod earbuds, however I chose to listen with Shure SE530s. I'm content with 500hp, yet many want 700+. There is always room for improvement!

 

+1. Very we'll stated!