Car Audio Central - Ultimate Car Audio Forum and Community

Steven wrote:Thanks again Jeremy, where do you get a computer based RTA? I was reading a post from Glasswolf about speaker imaging, he said to use a dash mat. What do you do, put a rug on the dash,lol.. Not trying to be funny:}

Dash mats are fugly, but you'd be shocked at the difference with one in place. Especially if you have tweets in the pillars, every little bit helps when you're trying to limit reflections.

?????? Yeah, I don't use a dash mat. I have my tweeters down in the kicks for now, with the mids in the doors. So I don't need one. Once I do move the tweets to my A-pillars I will play with the location for a while, and have a pretty good PEQ, and GEQ, so I sould be able to deal without one.

Plus the accord would look pretty funny with a rug laying across the dash.

RTAs, check out this link.

http://www.caraudiocentral.net/forums/s ... php?t=3173

Thanks again Jeremy, where do you get a computer based RTA? I was reading a post from Glasswolf about speaker imaging, he said to use a dash mat. What do you do, put a rug on the dash,lol.. Not trying to be funny:}

Steven, it sounds like your running into the same cancellation and phasing problems, we always try to warn people about. That many speakers, all at different path lengths is causing you all kinds of problems.

Think of it this way. Sound waves are an AC wave. When they arrive at your ear you want the waves from each speaker to be as close to the same polarity as possible. Thats why switching the polarity on one side can help center the soundstage (sometimes). Even with a simple two way component set, your never really going to get all the freqs to arrive in polarity with each other. Theres to many things for the waves to bounce off of, and the path lengths to your ear are to different.

Now let’s add in more speakers. Not only do you add in more AC waves arriving at your ears at different polarities, but now you have speakers sending out sound waves, canceling out other sound waves. (Any time a wave is met by a sound wave on the same freq but 180 deg opposite in polarity you will have cancellation.)

My suggestion, drop half of your speakers, and get (or build) one good 3 way or 2 way component set.

Or (granted this won't be near as good) You can make a few changes to what you have, and get it a little better.

First off, take the tweeters out of the dash. Focals hate being fired into the window. The A-Pillar is ok, but you will still need some tweaking.

Second, get a computer based RTA, and adjust each speakers polarity so they arrive at the mic in close to the same polarity. And adjust your EQs to give you a close to flat response curve.

Forgot, i have a PPI 450 pro mos for the Focals and a PPI a404 and a PPI a300 that i am using for the interiors. I have 2 PPi 2050am amps and a a100 here i'm not using at the moment:]

Yes, they are in the doors and iv'e sound deaden them very well. Lets see, i have a Eclipse 5423 hu, 2 Audio Control EQTs, 2Audio Control over drive line drivers, 1 PPI FRX xover, i use it for my subs. The subs are Pioneer TS-W305DVC in a sealed box, powered by a PPI A1200 amp. Front doors i have Focal Utopia 165W3 speakers and a set of Focal Polyglass 165V both sets are 61/2. Kick panels i have 4'' canton midrange with tweeters in the middle of them. In the rear doors i have a pair of 61/2 Infinity speakers and a pair of 61/2 Diamond Audio M361 speakers. Two 8" midbass Drivers in truck speaker boxes, i don't know if i'm going to keep them or not just trying them out. Oh, i have 4 sets of focal tweeters up front and the 2 that are in the kicks, 2 sets of focal tweeters in the rear. And i have that PPI DCX-1000, thats all i can think of for now, lol..

So what does the rest of your set up look like?

Off the top of my head, it sounds like something is wrong. Maybe the polarity on one of the mids, or where you have everything installed. I would set the x-over on your amp to about 80 with a 12db slope to start, and go from there.

One more thing. I am guessing the mids are in the doors. Make sure you sound deadon the inside of the door, and close off all the openings in the interior peice of sheet metal. (any sound deadoning matt will ork for this) You could be getting some cancelation if it is still open.

I think glass/kiki is out right now on a break...

Sory, it's a ppi 450 pro mos.

Hi Jeremy, i have a set of 3 way Focal 165w3 and a 4 chanel promos 450 powering them, the amp has no xover. The midbass, you can hardly hear it. The midrange and tweeters over power the midbass.