better performance from a bass knob?
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=102748
Printed Date: May 27, 2024 at 11:50 AM
Topic: better performance from a bass knob?
Posted By: Fosgate3
Subject: better performance from a bass knob?
Date Posted: March 03, 2008 at 8:22 PM
I have a Phoenix Gold LPL 44 bass knob on my PG XS2500 pushing a pair of Boston Acoustics G5 10's (dvc). The knob, when turned down, still does not attenuate the subs enough. I dont want to turn down the gain on the amp as the bass sounds sweet when I want it to hammer. However, it can be annoying if I'm listening to something "non-musical" (such as the news or something to that effect). The knob uses a 50K pot. Is there any way I can modify it so that it will turn the volume down on the subs more effectively than what it is doing now?
Replies:
Posted By: stevdart
Date Posted: March 03, 2008 at 8:32 PM
"the news or something to that effect" doesn't have content in the sub frequency range. Why are your subs responding? At what freq are they crossed to the front mids, and how steep is the cutoff slope? In those questions lies your answer. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: i am an idiot
Date Posted: March 03, 2008 at 8:49 PM
If you want to build a seperate volume control, the following picture will help you. The potentiometer in the drawing is available at radio shack, the part number is 271-1732. You will also need a project box to mount it into. and a patch cord to wire it up. This will be a volume control, you can turn it all the way down. This provides no boost or additional gain.  The 3 connections on the top row will be left. The 3 on the bottom row will be the right channel. I will try to dig one up and take a picture and post it.
Posted By: Fosgate3
Date Posted: March 03, 2008 at 8:57 PM
I truly appreciate the replies. Basically, can I change the pot out to a different one? will one give more of a volume range (or even, more of a "muting ability") than another? Another way of asking the question would be, if the limits of attenuation on the LPL44 are what I am currently experiencing, is there any way to modify it so that it attenuates the volume more or is "what I see, what I get"? I don't want to make a new bass knob as what controls the amp through a standard phone line with the pot, connected to the amp is efficient. In fact, for all intents and purposes, whether or not I am having bass out put or if I am trying to attenuate vocals on the same amp may be irrelevant.
Posted By: Fosgate3
Date Posted: March 03, 2008 at 9:02 PM
Here's a link to the package. You may have to copy and paste it into the address bar. https://img250.imageshack.us/my.php?image=lpl441gt1.jpg
Posted By: i am an idiot
Date Posted: March 04, 2008 at 5:57 AM
Changing the value of the pot will probably do nothing for you. It is the design of the circuit. It is doing exactly what they say it will do.
Posted By: Fosgate3
Date Posted: March 04, 2008 at 6:10 AM
Thanks for your reply and I see your point: Basically, this is the limits of the sub-knob circuitry inside the amp. I take it that using the design you provided, I could do what I want to do--go from wide open to completely mute.
Posted By: haemphyst
Date Posted: March 04, 2008 at 8:28 AM
Yes, the existing knob simply references voltage rails INSIDE the amplifier on the input buffers - semi-complicated - but that's effectively what it does. By "changing" the resistance on one or two resistors in the input stage, you are effectively "changing" the gain, without touching the knob on the amp. Most amps' remote knobs simply parallel with the internal gain potentiometer, some do not, however.
Yes. The design posted by i am will be an additional *in-signal-line* volume control. When installing it, turn it all the way up (zero attenuation) and set your gains as usual. You will probably be able to completely remove the PG remote knob, as well. Unplug it (and without removing it from the car) test that theory, but I am betting you'll be fine without the PG part.
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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."
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