setting hpf and subsonic 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=106302
Printed Date: May 03, 2024 at 9:54 PM
Topic: setting hpf and subsonic filters
Posted By: bullseye753
Subject: setting hpf and subsonic filters
Date Posted: July 22, 2008 at 7:50 PM
I have 2 boxes tuned to 40hz, no other components for the midrange etc.. just wondering what a good setting would be for my high pass and subsonic filters. subsonic: 15-35, high pass: 35 - 250
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Replies:
Posted By: DYohn
Date Posted: July 22, 2008 at 8:34 PM
This is for a subwoofer amp? Then you won't use a high-pass filter, you want a LOW-pass filter. Set it to about 100Hz. Is the enclosure ported? ------------- Support the12volt.com
Posted By: bullseye753
Date Posted: July 22, 2008 at 9:46 PM
ah my mistake, yes thats what i mean - low pass. If ported and vented mean the same thing then yes it is.. -------------
Posted By: DYohn
Date Posted: July 22, 2008 at 10:47 PM
OK, so if the port tuning frequency is 40Hz then your subsonic should be set to 40Hz which is pretty high. In your case your filter goes to 35 so that's what you use. That will be a pretty boomy system. ------------- Support the12volt.com
Posted By: bullseye753
Date Posted: July 23, 2008 at 12:13 AM
Do you say that as a good or a bad thing -------------
Posted By: DYohn
Date Posted: July 23, 2008 at 12:50 AM
For me it would be a very bad thing. I really dislike boomy systems as they are more suited to high SPL rather than listening to music. But hey, you might like it and that's fine. You may notice that you are missing the really low bass, though, and that it may sound way too loud in bands you don't want. But give it a try... what subwoofers are you using that had to be ported at 40Hz? ------------- Support the12volt.com
Posted By: bullseye753
Date Posted: July 23, 2008 at 11:53 AM
Yes you are very right. On the low end i get this kind of flapping feeling/sound.. you are able to tell its low, but its not that loud.. but it still shakes my whole freakin car like none other. I have two 12" L5's.. as you know it's an SPL sub so i guess it makes sense to have it tuned higher than lets say if i had a W7. The real reason theyre tuned so high is because i got 2 of them off a friend, and wanted to put both in. In a dodge neon that was going to be a trick, and i knew i was going to want them ported. So they had to be a compact ported which brought the tuning level up. I am currently at a stock alternator and would like to save that investment for another time. What i want to ask you is.. could i take one sub out, make a bigger box, and have it be louder/ sound better? I made both the boxes im using now so i woudnt have a problem getting another one. -------------
Posted By: aznboi3644
Date Posted: July 23, 2008 at 4:13 PM
DYohn...correct me if I'm wrong but isn't a subsonic filter a high pass filter???
Posted By: bullseye753
Date Posted: July 24, 2008 at 11:43 AM
Yeah they are the same, i think different amps use different names depending on if its mono or a multi channel. It shows the similarity in the names if you use the right words.. "let the HIGH frequencis PASS" and "block SUBSONIC frequencies" -------------
Posted By: KarTuneMan
Date Posted: July 24, 2008 at 11:54 AM
aznboi3644 wrote:
DYohn...correct me if I'm wrong but isn't a subsonic filter a high pass filter???
That would be a slightly odd, yet correct way of desribing it. set at 35 cycles, you would only get freq. ABOVE 35hrz. So yes, high pass. -------------
Posted By: bullseye753
Date Posted: July 24, 2008 at 2:10 PM
If i am trying to daisy chain my mono amp to a 4 channel amp, but my 4 ch has inputs for the front and rear, but only one pair of rca's running too it from my sub amp, how can i get a signal to both front and rear?
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Posted By: DYohn
Date Posted: July 24, 2008 at 3:30 PM
bullseye753 wrote:
If i am trying to daisy chain my mono amp to a 4 channel amp, but my 4 ch has inputs for the front and rear, but only one pair of rca's running too it from my sub amp, how can i get a signal to both front and rear?
Normally you would use two sets or RCA cables, one from the Front pre-out of the HU and one from the Rear pre-out from the HU to supply a signal to the 4-channel amp. If the HU has a separate Sub pre-out, a third set of RCAs is used for that. If not, assuming the 4-channel amp has a pre-out, daisy chain the sub amp from there. If you are sending a single full-range signal to your sub amp, there is no good way to daisy-chain a 4-channel amp from that - unless you don't care about front-rear fade? Then use a y-cable. ------------- Support the12volt.com
Posted By: bullseye753
Date Posted: July 24, 2008 at 7:38 PM
I only have one set of preouts from the H/U.. which is currently taken by the sub amp.. so what should i do? The 4ch is a JBL CS50.4 if that helps
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Posted By: i am an idiot
Date Posted: July 24, 2008 at 7:53 PM
If you only have one set of RCA jacks on the back of the radio, you must (as DYohn said earlier) get a set of Y adaptors from your local stero shop. Tell them you need 2 Y adaptors with 1 female and 2 males on each adaptor. When you connect them, connect one to the left RCA that comes from your bass amp and then connect the male ends to the left front and left rear inputs of your amplifier. Then connect the other Y to the right RCA coming from the amp, then connect the male ends to the right front and right rear inputs of the amp.
Posted By: crazyinstalls
Date Posted: July 24, 2008 at 8:06 PM
to the dude who had neon i just sold mine but a lil trick a hemi or bigger dodge alternator works and bolt right up to the neon with a modification on the plug on the top side puts out double the amps!
Posted By: i am an idiot
Date Posted: July 24, 2008 at 8:13 PM
From crossover settings to getting all 5 or 6 channels of amplification to work with only one set of RCA cables, to neon and alternators. Anybody got anything else?
Posted By: DYohn
Date Posted: July 24, 2008 at 8:15 PM
I was thinking about seeing "Dark Knight" this weekend. I hear it's pretty good. 
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Posted By: i am an idiot
Date Posted: July 24, 2008 at 8:18 PM
I heard that too. What time are you planning on going?
Posted By: DYohn
Date Posted: July 24, 2008 at 8:20 PM
First matinee on Saturday. Can't handle all the kids with their damn boom-cars at night.  ------------- Support the12volt.com
Posted By: i am an idiot
Date Posted: July 24, 2008 at 8:34 PM
Hey if somebody has a stiffening cap laying around and wants to stop their headlights from dimming, I have a plan that should work. I do not want you to go and buy a cap but if you have one and want to try this, let me know how it works. A (.)5 farad cap should be plenty. If you use a 1 farad you may need 4 diodes to handle the charge current. You will be charging the cap everytime you turn on the lights. The diodes are necessary, they prevent the current from supplying the amplifier. For testing purposes you could simply connect the diodes, the cap and a headlamp bulb to try it. Let me know if it works. 
Posted By: bullseye753
Date Posted: July 25, 2008 at 12:30 PM
I may give that a try.. i have a .5 farad RF cap laying around
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