| Author |
Thread: Amp clips before my sub reaches Xmax!!! HELP ME |
    
clipinamp Unregistered guest |
| Posted on Sunday, August 08, 2004 - 11:52 pm: |
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Ok...i have a JBL BP600.1 (4ga. power and ground) and a Brahma 10" (1.65 cu ft vented box).
when i go to set the gain, the sub gets louder but before it reaches its Xmax it starts to distort...not completly sure why...
i have narrowed the problem down to that i only have 100A alt...could this be it??? My voltage rail does drop when the bass hits, so do i need a bigger alt...if so then of big of one.
i say a "200A" on ebay, but it said that it puts out 100A at idle and 200A max...is this good enough?
someone help me out here! |
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clipinamp Unregistered guest |
| Posted on Monday, August 09, 2004 - 09:33 pm: |
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anyone???
i need to get this fixed this week!!!
i'm goin to college the 16th! |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 1050
Registered: May-04
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| Posted on Monday, August 09, 2004 - 10:06 pm: |
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Yeah, you probably need a new alternator. If your gains are set incorrectly, then the voltage rail will sag as well, gain will usually be below half with a good aftermarket head unit. Make sure no bass boost etc. is engaged as well, a clipped head unit signal can cause distortion as well. That 1 ohm load probably isn't helping the alternator much, it'll pull a good bit of current. A 200A alternator will provide plenty of current for a JBL 600.1. After that, maybe you can get a capacitor for the very demanding bass hits. How do you know when the sub is about to reach X-max anyway, just out of curiosity? |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 1052
Registered: May-04
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| Posted on Monday, August 09, 2004 - 10:12 pm: |
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Also, when setting your gains, make sure the head unit is about 3/4 volume. A more accurate method is to turn the gain down all the way, and turn the head unit up until you can hear distortion from the sub. Once you hear distortion, that is a sign that the head unit is clipping. Now turn the head unit's volume down until clipping just stops, then proceed to adjust the gain on the amplifier, again stopping when distortion occurs. If you use a stock head unit with line out converters, then you'll get distortion from those as the signal comes from an amplifier (a crappy one at that) instead of a preamp. |
clipinamp Unregistered guest |
| Posted on Monday, August 09, 2004 - 10:52 pm: |
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the brahma has bout a 2.1" xmax...the blur depth is bout 1-1.2" when it starts to distort.(even in its vented box)...i know the JBL 600.1 has plenty of power to make it hit its xmax...but the sub doesnt even get to the point at which it has that "full" sound before it distorts...
i have a cap...2 farad...it didnt help me, so i figured it was the alt.
i have a DEH-p6400 (pioneer) HU...i am settin the amp gain just as you say...the amp clips w/ the gain at about 1/3...
its like the amp's not putting out the power that it should...
just thought of one other thing...do you think that this could have something to do w/ my RCA's (they are walmart cheap-O's...lol)...also, i had to put a ground loop isolator in to the sub wouldnt make a THUMP when i changed CD's or turned the HU off...could one of thoughs have something to do w/ it???
oh and do you think i should go ahead an get the 200A alt?
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Gold Member Username: Jonathan_f
GA
USA
Post Number: 1054
Registered: May-04
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| Posted on Monday, August 09, 2004 - 11:09 pm: |
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RCAs could benefit, but better RCAs are more of a noise prevention issue rather than distortion. I think you should go ahead and get the alternator. Like I said above, make sure bass boost on the HU and amp is off and that the sub level is set flat. |
clipinamp Unregistered guest |
| Posted on Monday, August 09, 2004 - 11:13 pm: |
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oh...this is the alt. i'm lookin at:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7914378710&ca tegory=33573&sspagename=WDVW
is it a good one? |
clipinamp Unregistered guest |
| Posted on Monday, August 09, 2004 - 11:14 pm: |
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oh...this is the alt. i'm lookin at:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7914378710&ca tegory=33573&sspagename=WDVW
is it a good one? |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 1055
Registered: May-04
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| Posted on Monday, August 09, 2004 - 11:21 pm: |
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Yep. It'll be sure to give you enough current. By the way, I was asking if you knew it was close to X-max b/c some people have tried measuring it w/ a tape measure lol. Not an accurate method. Really, it's hard to tell by the blur of the sub as well. 1"-1.2" is about the one way X-max of a Brahma, if your sub was only moving one direction, then you may have been reaching X-Max. Of course, two ways it will be twice that linear. |
clipinamp Unregistered guest |
| Posted on Monday, August 09, 2004 - 11:56 pm: |
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yea...its only gettin half its xmax before it distorts...
is this most likly because of my stock alt??? |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 1058
Registered: May-04
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| Posted on Tuesday, August 10, 2004 - 12:21 am: |
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Could very well be. Hard to say, but saying your voltage rails drop on those low notes I'd definately say it is a problem. |
