PDA

View Full Version : EQing a dip? (Now with pictures!)



idiot
06-19-2007, 07:50 PM
How easy would it be to fix the ~1.2kHz dip in the graph below? I'll be using the 880PRS for processing. I've never messed with an EQ in either home or car systems, so I have to ask. Doesn't seem like it would be difficult, but that's a pretty substantial dip...

http://www.zaphaudio.com/6.5test/8945P-FR.gif

I'm thinking of trying to put these bad boys in my door:

http://www.partsexpress.com/imageslarge/296-602L.jpg

squeak9798
06-19-2007, 07:55 PM
Honestly the frequency response in that graph doesn't matter one lick since that response was not measured in your vehicle...where the speaker will be located.

That graph is not representative of the response you'll have with the speaker installed in your vehicle.

The response is going to change drastically from that graph once you install the speaker in your car.

DBfan187
06-19-2007, 08:17 PM
Yeah idiot.

idiot
06-19-2007, 08:17 PM
Couldn't you say the same about running this in someone's dorm room, since the graph was likely taken in an anechoic chamber? Yet the home theater guys are all about throwing in notch filters and ridiculously low crossover points to try and obscure the dip, despite the fact that the rest of the frequency range will no longer be flat in a real room and will require minor EQing as well. Obviously a car is a much worse environment, but wouldn't this at least indicate that a big trouble point will be around the 1.2kHz area?

I need an RTA.

squeak9798
06-19-2007, 08:48 PM
Couldn't you say the same about running this in someone's dorm room, since the graph was likely taken in an anechoic chamber? Yet the home theater guys are all about throwing in notch filters and ridiculously low crossover points to try and obscure the dip, despite the fact that the rest of the frequency range will no longer be flat in a real room and will require minor EQing as well.

The effects of room acoustics will be much less severe than in a vehicle. So it's not quite the same comparison.


but wouldn't this at least indicate that a big trouble point will be around the 1.2kHz area?

Your vehicles acoustics and installation are going to completely swamp almost all of the driver's own inherent frequency response characteristics.


I need an RTA.

Indeed.

That is about the only way to do this.

That and a good ear......

jmanpc
06-19-2007, 08:50 PM
auto eq on the 880 ftw?

idiot
06-19-2007, 10:41 PM
Well, I have a db meter... maybe that can serve as a poor man's RTA. ;)

Has anyone here installed the Usher 8945P's? I'm going to mate them with a 1" dome tweeter. It'll be my first active setup with any kind of processing, so I'll probably be back with more stupid questions before I'm done.

helotaxi
06-20-2007, 07:02 AM
I'd be more concerned about the peaks above and below the "dip" than the dip itself.

You can get RTA software for your computer for not a lot of dough.

idiot
06-20-2007, 07:26 AM
I'll probably put a lpf on the woofer somewhere around 1.6kHz, so the upper peaks won't be too much concern. My tweeters should be able to be crossed around 2kHz without an issue.

What kind of microphone would I need to run the RTA software?

helotaxi
06-20-2007, 09:35 AM
A decent measurement mic would be best but you can calibrate a lesser one to work well enough. You will also need a mic preamp. You can get both on eBay for not a lot.

idiot
06-20-2007, 10:27 AM
In that case, I have the mic but not the preamp.

Thanks for the help.

DBfan187
06-20-2007, 11:30 AM
http://www.caraudio.com/forum/showpost.php?p=2535289&postcount=28

idiot
06-20-2007, 12:51 PM
Yep, I have that Behringer mic already. Thanks for the link to the preamp and program. I'll have to pick those up eventually.

ARSkemp
06-20-2007, 09:50 PM
http://www.caraudio.com/forum/showpost.php?p=2535289&postcount=28

Would it be better to use this than the auto-eq already on the 880prs or will the end result be pretty much the same either way?

squeak9798
06-20-2007, 10:14 PM
Would it be better to use this than the auto-eq already on the 880prs or will the end result be pretty much the same either way?

Most Auto-EQs built into headunits **** ***........better off doing it the ole' fashion way