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matching hu/amp freqs

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=114796
Printed Date: May 11, 2025 at 6:46 PM


Topic: matching hu/amp freqs

Posted By: thatfloorguy
Subject: matching hu/amp freqs
Date Posted: July 01, 2009 at 7:06 PM

Ok so I searched the site but still have questions (sry) pioneer deh4900 kicker 08zx350.4    kicker 08zx750.1  08s15L74 wired to 2.  I found an old post abt setting the LPF on sub amp and HPF on main amp to 80-100 hz.  I have the HPF on my HU @125 now and the LPF for the sub(HU) @ 80. Do I want to try to match all freqs, including the ones on the amp? The thread I was looking at, the guy was instructed to set his HU sub LPF to 120. My subs specs are 18-100 HZ.  Do I set evrything to 80 ? OH the enclosure is 4.75 net 65 sq in port tuned to 40 hz. Just looking to get the best possible sound with what I now have. I know most will say to throw out the HU but that is not an option at the moment,lol.  I also don't have a clue abt the sub menu on the HU's audio setting. It expands to allow tweeking even more freqs. I am assuming the mids/highs. I have the bass boost on too. Should that be turned off as well?

Thanks;  Mike




Replies:

Posted By: DYohn
Date Posted: July 02, 2009 at 9:29 PM
Yes, if your sub LPF is set to 80Hz, your main woofer HPF should also be set at 80Hz.

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Posted By: haemphyst
Date Posted: July 02, 2009 at 10:17 PM
DYohn] wrote:

Yes, if your sub LPF is set to 80Hz, your main woofer HPF should also be set at 80Hz.

...that, and you should only be using ONE crossover... Either on the HU end, or on the amp end. Stacking them generally isn't a good idea.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: ianarian
Date Posted: July 02, 2009 at 10:54 PM
I listen to mainly rap, never owned or installed a system for any rap listener that could cross over highs that low. Lets face it, the speakers in each system are the deciders of your crossover points. If you play your music with the most bass, start high and lower the x-over level while watching the speakers. You will know what your level will be. Match your sub to the level your highs play best at. My preference has been L-60Hz/H-130Hz +/- ever since I been putting systems in my rides. Stupid RTA's (IN MY CASE) only caught a little dip in the 100hz range. Of course it also caught some other undesirable ranges causing huge fail.LOL but F|_|CK it, my preference is no where near the politically correct range. Im going to post a special Pro's VS Joe's post here in the near future..PLZ read it!

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Posted By: thatfloorguy
Date Posted: July 03, 2009 at 8:03 AM
So would I be best to to set the HU crossovers to flat and make my adjustments using the amps? I can set the HP to off but I think the LP is automatic when I turn the sub setting on.Do I make these adjustments prior to setting gains? The way it is now the sub amp gain is all the way down(for lack of a better term) and I just turn up the bass boost to add the thump when needed/desired. I do not own or haave access to a multimeter so it will be done by determing closest freqs on the marks of the amps settings. With the HP off at HU it allows some bass to mids/highs which of course doesn't sound very good on  the pioneers. The FIE appears to shut off the rears altogether. I plan on replacing everything but the amps and sub as $ allows. I thought pioneer was pretty good and I have like $500 in HU/speakers. Wish I had known abt this site then lol.




Posted By: DYohn
Date Posted: July 03, 2009 at 9:24 AM
I suggest starting by setting the crossovers on your amps to full pass or off if possible and using the ones in the HU.  Set them to the same value, I suggest 80 or 100Hz.  Set your amp gain properly.  Check the Car Audio Hot Topics forum for instructions.

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Posted By: thatfloorguy
Date Posted: July 03, 2009 at 7:40 PM
Ok the main amps (amp  08zx350.4) have HP/LP/off,as well as high/low button(set to high).  (I set rears to off fronts to HP) x-over to fronts is @ abt 150 on amp. The sub amp 08zx750.1 has no xover just the button high/low, it is on low. I turned off sub@HU and adjusted the front/rear seperately with the amp,unplugging rca's@amp. I like the sound of it and have no distortion w/HU@ 45 volume. I have the HU HP@80 and HU LP@80 gain all thye way down on sub amp. HU set to flat balance,fade.high,mid,and low. Also bass boost on HU flat and @ sub amp. Do I now set the gain for the sub amp? I turned sub on @HU and it sounds pretty good all the way down. I dialed in more bass w/the wired bass remote on the sub amp. Do I need to put that @ 1/2 way before adjusting the gain? I rarely pass the halfway mark on that. Also what are the freqs. on the sub-menu on the deh4900IB? When I hold the audio button abt 3 secs a sub-menu pops up?  Maybe I should make a new post when I upgrade but will the 08zx350.4 (being 2 amps) run 2 sets of decent components W/ x-overs or do I run 1 high-end with tweets on the 2nd amp/channel? I plan on making custom kick panels for the doors.




Posted By: thatfloorguy
Date Posted: July 03, 2009 at 9:50 PM

If I can get access to a DMM do I unhook the sub @ the speaker outputs and adjust the gain until I hit 4v or just under? That is the voltage output of my RCA out( supposedly )  A buddy of mine said that is how I should set my gains. *this site is addicting* I thought I was "bumping" I now realize the chase.posted_image   The advice one has access to here is priceless.






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