# Help with REW in car audio DSP setup



## mojozoom (Sep 25, 2012)

Here's my first post - glad to have found this forum and REW. Absolutely amazing software package.

I'm using REW with a fast laptop and Audyssey microphone to setup my car audio system, which is the typical sub in the back, 6.5" mids low in the doors, and 1" tweets in the door mirror area sail panels. It's a small Mazda 3 hatchback. I take measurements with the mic on each shoulder on order to account somewhat for my giant nogging being in the middle of things. Adjustments are made via 3sxty.2 DSP unit that has 31 band graphic eq's and adjustable time delay for each channel (only and 9 bands of GEQ for the sub).

I've looked at a bunch of target curves and picked one that's somewhere in the middle and pretty widely used and well respected, so it should be reasonably close to decent sounding.

But it isn't.

I've used both sweep measurement and RTA to base eq adjustments on, and the RTA results do end up slightly less bright and tinny, but still lacking mids and lower mids. The sub bass is pretty nice. I've ended up cutting 200 & 250 hz substantially based on the sweep or RTA results, and it seems like that may be alot of what I'm missing. 

Any car is a highly reflective small room, so I'm wondering if possibly there are resonances that are adding in to the overall measured results and driving them up, so then I end up cutting where I really shouldn't. I'm guessing that's where adjusting the time windows could really help with what I'm doing, but I'm not sure how best to tackle that without making a mess of it as I'm pretty new at this.

Could anyone offer any advise on things to try? Thanks for your time and help!


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## hjones4841 (Jan 21, 2009)

First, a warm welcome to Home Theater Shack!

Using the Audyssey mic may be part of your problem if it is one that came with a receiver. Its frequency response won't be linear. The receiver has EQ that corrects for the mic's FR errors.

A better solution is one of the Behringer ECM8000 mics, but it requires a polarizing voltage from a mixer. An inexpensive mixer will work fine, but the pair will run you $125-150 or so.


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## Wayne A. Pflughaupt (Apr 13, 2006)

What Mr. Jones said. Frequency response measurements are only as good as your mic. AVRs use inexpensive mics, and the “correction” for their non-linear response is built into the receiver itself. Measurement results from a mic like that are fine for “FYI” readings, but if you’re intending to equalize your system you don’t want to do that based on anything less than accurate measurements. You need a mic with a custom calibration file and an appropriate mic pre-amp with phantom power for your application..

Regards, 
Wayne


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## mojozoom (Sep 25, 2012)

The mic was the first thing I questioned as well, but after some more re-researching I'm pretty confident that it's flat enough for what I'm doing here. Cross Spectrum Labs did some testing on a few of them a while back:








I'm starting to wonder if my target curve just doesn't roll the top end off fast enough in the small, highly reflective environment. I've read that the slope of a room curve needs to be steeper as the room gets smaller, and this is one small room!

Here's the target I was chasing:








Wayne, I think your final curve was alot steeper than my target here.

I'm going to spend some time just listening to familiar tracks and eq'ing blindly, and see where the curve ends up, then smooth from there. That should be enlightening.

Sorry about the attachments - I don't have enough posts yet to insert pics. Thanks again for the input!


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## Wayne A. Pflughaupt (Apr 13, 2006)

Hey mojo,

I don’t think it’s the reflective environment so much as the immediate proximity to the speakers. Anytime you’re really close to the speakers, the highs typically need to be attenuated.

Also, that target curve you’re using looks like a home theater house curve? It’s not going to work for a car. I’ve heard that the sub boost for a car needs to be somewhere between 20-30 dB. You might also need to flatten the target more between 40-400 Hz – that should help your low-mids issue.

You might want to ping Sonnie. He’s used REW with his car stereos; perhaps he can give you some pointers.

Regards, 
Wayne


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## korykx (Mar 5, 2012)

Another issue could be with the 3sixty.2! There are a number of DSP processors out in the market now that will run circles around the 3sixty.2. I have had numerous problems with the 3sixty.2 in the past, not a very well built unit due to Rockford trying to make the unit price friendly for consumers. When they worked, they worked awesome!


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## mojozoom (Sep 25, 2012)

The only problems I'm aware of with the 3sixty.2 we're related to bluetooth connectivity, and that was resolved with the V2 (which I have).

Mine is rock solid and really fun to use. I know there are better units available now (MS8!), but my system is a budget build and I picked the 3sixty.2 up for $80 used on CL.


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