Celica Speaker Placement, Measured Options

[skogs]

Hi. I'm a real audio enthusiast, so along time ago i bought som measuring equippment, mostly to use indoor. But now i've also used it in my celica, because i had some trouble getting the system to sound right. I used quit some time figuring this out, and it turned out really well ( and reeally loud!), so i thought i might share some tips and experience i got from it.

It seems that the rear seat panel placement induces a huge and quite narrow peak sentering around 150hz, and a smaller broader one at 1,5khz.
The front door placement, either top or bottom, induces a really big and extremely annoying peak at 1,5khz.

I would recommend using a single 6" in each rear side panels, throw away the tweeter. Use your amps "low-pass" to cross over at around 500hz. This is to avoid making the problem at 1,5khz any bigger. I would also recommend putting a 80-100uF capacitor in series with the speaker, to cool down the peak at 150hz a little.

The front door speaker can now be crossed over at the same frequency as the rear speaker, using your amp's "high-pass". On the front system you'll keep the tweeter, and preferably place it on or in the mirror cover. Do not place the tweeter in the inner corner of the dash.

Then you can cross your sub over at around 100hz, adjust the gain fairly high. You will now have a lot of output from 40-200hz, which will really kick your ass. You will notice that the rear speakers will offer a LOT of output compared to would you would expect from that driver. The front speakers will barely have any cone movement, even at high levels, so you could easily use 4-5" drivers.

Your system will now still have some issues at the 1,5khz region, this is just because of the resonances that the interiør of the car induces. So there is two ways to fix this problem:
The easiest way is to use EQ to cool down the 1,5khz region, and while your at it, ease down the 150hz region as well.
The hard way is to use an extra speaker, with a narrow bandpassfilter, to rise the sensitivity on the system between 300-1000khz.

Sorry for the long post, really hope its of any help:)

This post has been edited by skogs: May 8, 2009 - 2:17 AM