sor

Yeah, I read that. Problem is that we can't remotely compare with different source audio, volumes, and uncalibrated meters. I did notice though that your looks flatter than stock. Stock bass is low until 100hz or so when the woofers kick in.

pbcsd

Is that using the correction files for the SPL meter (Ratshack I assume?).

Also, did you take the same for the stock sub?

sor

Maybe someone else can confirm my numbers, but I hooked an O-scope to the stock sub, pumped a 30hz sine into it and the results were interesting. At about 60% volume the voltage stopped increasing to the sub, but the other speakers kept getting louder, apparently they've got it set such that it won't clip. It stopped at 30v peak to peak, which the o-scope calculated as ~10 volts RMS (15v x.707) So the sub is getting 12.5 Watts max.

sor

Err 12.5 Watts RMS, max :-)

sor

Just did a sub swap. Will post details later, but I did some tests and two things:

1) spl tests show that it IS quieter at low volume (4 clicks).

2) at 10 clicks, it is more than twice as loud as stock in the very low end, and then the stock system bumps up past 40hz and they converge as the other speakers come in.

pbcsd

Wonder if that means the stock driver is closer to 90db sensitivity or so? Would be nice to find a 90db 10" driver that would work...

sor

SUB SELECTION:

I narrowed my options down to the Polk MM1040 or the Alpine SWR-T10. Both are 'thin' style subs. The Polk had high sensitivity going for it at a whopping 91db... but wait! 91db at 2.83v, that's NOT 1W on a 4 ohm sub, this sensitivity number is actually @2W. I understand why they'd do this, since 1W on 4 ohms is actually lower on the volume **** than 1W at 8 ohms, so this helps compare the output at an identical volume **** position, but it kills the comparison between other 4 ohm subs.

Either of these subs would be about as good of options as the others already mentioned in the thread. The Polk's advantages are higher excursion (25mm, good for IB) and higher sensitivity, the Alpine's advantages are good excursion (15mm), higher Qts (.53, better for IB), lower Fs(32.5hz), and higher power handling. I didn't care about the sensitivity as I planned from the beginning to use a sub, so I went with the Alpine, but I think for those who don't want an amp, the Polk would be worth looking at. Though the Qts isn't as high it's about the same as the other options given on here and people seem to be getting good results with those.




The alpine is rated for 600W RMS, I will probably drive it with an amp that does 200-250 due to the IB installation. I think that will work out really well based on how it sounds with the stock amp at 12W RMS.

INSTALLATION

It is difficult to tell which subs will work with the existing hole. This sub barely fit when top-mounting, it sat up about 1" off the deck, but it looked like the surround might contact the deck cover under heavy excursion, so to be safe I bottom-mounted. Not a big deal since it's a thin sub, but you'll notice that I had to add a spacer in order to ensure that it won't contact the deck during excursion. In the end I lose about the same as what others are with the Kicker and JL sub. Which to me is pretty much nothing to lose a few inches in a largely useless area of the trunk anyway. As long as I don't loose floor space in the trunk and don't have to deal with a box I'm happy :-)











RESULTS:

I can definitely see why people like this 10" swap, and I think that it's due to the lower resonant frequency of most of the 10" speakers. Even though they don't provide as much bass at many points, they DO provide significantly more in the 30hz range, which adds a deep richness to the music. At listening levels things pretty much trade off, with the 10" you get good 30hz (4x louder!!), good 50hz, with the stock you get good 40hz and good 60hz, but the overall output on average is roughly the same. I'd be interested in others posting their numbers with my test for comparison. At soft volume you still get slightly more low-end (resonant frequency again boosting us), but less overall output. I don't think this is a problem though, since the tests were done with the bass setting centered, and most people crank it up, so you're pretty much always going to be in the medium volume range.

audifan22

Sor, thanks for the details, let me ask you something as I'm no audiophile, but are you saying the 10" replacement doesn't really bump that much more bass than the original B&O? I was hoping that with a 10" replacement, that if I had the MMI bass settings on high the system would crank enough where you could feel the bass, but if I wanted it to be closer to the stock bass output (at highest setting) I would put MMI settings for the replacement at about mid level.

sor

It IS an improvement, but it doesn't drastically change the system into one that will vibrate other cars or anything. The best way I can describe it I think is that it sounds close to stock, except now when there is low bass in a song I can feel it. It vibrates your back support a bit, etc. Nothing like a dedicated amp if you're used to that, and in fact I was a bit disappointed that some of my favorite bass guitar riffs don't seem to have been improved any, but overall it's better in a subtle way. If you expect it to 'bump' or 'hit hard' when you crank the bass level, don't.

If you listen to rap/techno or songs with synthetic bass or deep bass notes, you will love this cheap upgrade as you will be able to 'feel' what you've been lacking. If you listen to rock/pop, etc you will only notice the difference as you crank up the volume and find the bass keeps up longer. Wish it were easier to explain what sounds are in the 25-35hz range, but that is really where going to the 10" pays off.

sor

Still, if you're not interested in a dedicated box, it's easy to do this and mount an amp to the underside of the deck if you want a little more. That's what my plan is.