amp settings

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=58517
Printed Date: June 18, 2025 at 8:03 AM

Topic: amp settings

Posted By: whitevelvis
Subject: amp settings
Date Posted: June 28, 2005 at 4:47 PM

Could anyone offer some initial settings for sound quality for both of these amps. Hopefully I can get a good jumping off point and tweak it a little here and there. Thanks for the replies.

99 Nissan Maxima SE

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99 Nissan Maxima SE
Alpine CDA-9847
JL Audio VR 6.5" frt/rear
powered by an MB Quart RAA4200
2 MB Quart 10" PCE254 in a QLogic ported box
powered by a MB Quart RAA2400

Replies:

Posted By: haemphyst
Date Posted: June 28, 2005 at 6:22 PM

ummm... WHAT amps?

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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: whitevelvis
Date Posted: June 28, 2005 at 9:43 PM

my apologies, i thought it showed up in my signature. this is what im running

Alpine CDA-9847
JL Audio VR 6.5" frt/rear
powered by a RAA4200
2 PCE254 in a QLogic ported box
powered by a RAA2400

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99 Nissan Maxima SE
Alpine CDA-9847
JL Audio VR 6.5" frt/rear
powered by an MB Quart RAA4200
2 MB Quart 10" PCE254 in a QLogic ported box
powered by a MB Quart RAA2400

Posted By: whitevelvis
Date Posted: June 28, 2005 at 10:12 PM

I made some adjustments on it tonight and it sounds very good, but now ive got alternator whine coming through. does too much gain cause this? ill make a note of the settings and post tomorrow.

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99 Nissan Maxima SE
Alpine CDA-9847
JL Audio VR 6.5" frt/rear
powered by an MB Quart RAA4200
2 MB Quart 10" PCE254 in a QLogic ported box
powered by a MB Quart RAA2400

Posted By: whitevelvis
Date Posted: June 30, 2005 at 7:37 AM

THE 4200
gain-about 2 volts, range-x1, freq-about 180Hz, type-hpf, filter-off, f/e defeat-off

THE 2400
rgain-about 2 volts, range, x10, freq-about 1kHz, type-lpf, filter-on, lgain-about 2 volts, f/e defeat-off

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99 Nissan Maxima SE
Alpine CDA-9847
JL Audio VR 6.5" frt/rear
powered by an MB Quart RAA4200
2 MB Quart 10" PCE254 in a QLogic ported box
powered by a MB Quart RAA2400

Posted By: DYohn
Date Posted: June 30, 2005 at 8:21 AM

whitevelvis wrote:

I made some adjustments on it tonight and it sounds very good, but now ive got alternator whine coming through. does too much gain cause this? ill make a note of the settings and post tomorrow.

Yes, high gain can cause alternator whine but more likely is poor quality ground. Make sure you have good ground connections to bare metal on the vehicle's chassis. You need to set the gains to match the maximum HU unclipped output, not by eyeball or guessing or using any voltage markings on the amps. There are many ways to do this depending on your skill level and available equipment. Do a forum search for "gain setting." Post back if you can't figure it out.

As far as your amplifier crossover settings, I suggest setting your sub amp as a LPF (low pass filter) at approximately 80Hz. Set the mains amplifier as a HPF (high pass) at the same, 80Hz. If the mains bottom out or can't handle the bass, raise it a bit to around 120Hz, and be sure to match that setting wiht the sub amp. This will not be ideal as bass becomes directional above 80, but you do not want a big hole in your overall system response. Turn any bass boost or amplifier EQ "off."

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Posted By: Poormanq45
Date Posted: June 30, 2005 at 9:41 AM

Like Dyohn said, the most likely culprit for the alternator whine is a faulty ground, but you are correct in saying that improper/mis-aligned gains can cause that.

Having one gain set too hihg/low relative to an internal/external gain setting will cause a noticable humming/hissing noise.

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