are there high frequency filters?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=55596
Printed Date: May 03, 2024 at 6:25 AM
Topic: are there high frequency filters?
Posted By: ketchup_gsr
Subject: are there high frequency filters?
Date Posted: May 12, 2005 at 12:07 PM
hi i have have problems with high frequency noise, i was wondering if there were high frequency filters that would block frequencies above 20kHz. Thanks.
Replies:
Posted By: DYohn
Date Posted: May 12, 2005 at 12:54 PM
Sure, you can either buy or build a filter for any frequency band you wish, but if I was you I'd try to fix the problem, not mask it. Plus, if it's an annoying sound that you can hear over or during music, it is probably not above 20Khz but more likely in the normal music band so it's not something you want to eliminate. What exactly is your problem? Please include the make/model of the vehicle, your amps(s) and your head unit, and describe the symptoms you are hearing and maybe we can help. ------------- Support the12volt.com
Posted By: ketchup_gsr
Date Posted: May 12, 2005 at 4:19 PM
yeah i know i should fix it, but i'm really busy lately, so i'll have to mask it for now. work isn't giving me much time to do anythign else, and i drive an hour each way, and the noise is killing me. oh and i don't hear the noise, i know if i turn down my 12khz setting on my crossover it helps a little. so i figure it may be high freq noise, and also cause dogs act funny when i drive by =)
Well i have a phoenix gold 5.1MT amp, a clarion 744 crossover, and stock speakers. as for my head unit, i really don't have one, it's more of a computer.
so where can i buy one of these 20kHz filters? or where are the schematics to build one? thanks a bunch
Posted By: DYohn
Date Posted: May 12, 2005 at 4:57 PM
Sounds like a typical ground issue, especially with a computer. Ground the power supply to the car's battery. If you're using stock speakers (UGH!) why do yu have a crossover? If you really want to build a low-pass high-frequency filter, a simple first order system would ba an inductor in series with every speaker. I suggest trying about 0.04mH (assuming a 4-ohm speaker.) You may have to wind your own to find one that small, by the way. Or get a good full-range 1/3 octave graphic equalizer, which will have the added advantage of being infinitely more flexible. ------------- Support the12volt.com
Posted By: ketchup_gsr
Date Posted: May 12, 2005 at 5:26 PM
ground noise? i made sure that everything was connected to a single point in the car, and that if was as close to the frame as possible. i sanded the section down and used a 4-gauge cable with a star ring to grind into the metal...
hmmm, interesting thought though.
do you have schematics or a link to a web site that desceibes how to build it? thanks
Posted By: klee1981
Date Posted: May 12, 2005 at 8:02 PM
That sounds like ground loop to me. I was alright, and had no noise, until I added my cheapo lanzar crossover, then I would hear a high pitch whine when I would rev the engine, only from the fronts, so I went to radio shack and bought a couple ground loop isolators. This really did mask the problem, but I couldn't hear it, and thus I was then satisfied. I subsiquently I removed the crossover after I opened the trunk after rain and poured water all over it, killing it. I now use the x-over in the headunit, and am satisfied again. Kevin ------------- Sony CDX-f5700
Hifonics Zeus 170x4 zx6400
JBL BP1200.1
2 infinity Perfect 12" subs
1.70cft, 37hz
Infinity CS5000 Front 5.25" and Tweeters
Infinity Kappa 6x9" Rear Mids
Pioneer 4" rear tweeters
Posted By: ketchup_gsr
Date Posted: May 12, 2005 at 9:34 PM
i don't hear anything when i rev, it's just that after sitting in my car for about 10 minutes my ears start to hurt. The volume in my car is pretty low. my ears hurt anyways. when i turn off my system, my ears feel better.
I'm just wondering how to fix this problem.
Posted By: klee1981
Date Posted: May 13, 2005 at 7:16 PM
I like trobleshooting. - does this noise stay steady, or go loud and soft when you drive, turn the AC on, lights, ect? - Is this noise up front, in the back, or in the trunk? - how loud is this noise in relation to the music? - Does this sound get louder as you turn up the volume? - Do you "hear" the sound or do you just have a mysterious headache when you listen to the music? thats all I can think of for now. Kevin ------------- Sony CDX-f5700
Hifonics Zeus 170x4 zx6400
JBL BP1200.1
2 infinity Perfect 12" subs
1.70cft, 37hz
Infinity CS5000 Front 5.25" and Tweeters
Infinity Kappa 6x9" Rear Mids
Pioneer 4" rear tweeters
Posted By: ketchup_gsr
Date Posted: May 17, 2005 at 10:51 AM
hi klee
the first 4 questions don't really apply as i don't hear the sound, but as to question 5...
i do just get a mysterious headache after a while... the first thing that happens is that my ears start to tingle, then ache...
i was thinking it was just in my head, but after i got a friend to listen, without telling him there was a problem... he said he his ears hurt too... so i guess it's not just me.
Posted By: DYohn
Date Posted: May 17, 2005 at 11:03 AM
Go put an RTA on your system to find out what's going on. Sounds like what you need is an equalizer. ------------- Support the12volt.com
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