Sub Amp Needed
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=44713
Printed Date: May 16, 2024 at 5:35 AM
Topic: Sub Amp Needed
Posted By: xandos9
Subject: Sub Amp Needed
Date Posted: December 08, 2004 at 11:38 AM
I have three 12 inch 4 ohm 150 RMS subs. I would like to know what would be a good amplifier to buy. Right now I am looking to buy this amplifier. https://www.thecarstereo.com/product/product_view.php?product=APMC01984
I'm not sure if this amplifier is overrated. I would like some opinions.
Replies:
Posted By: pimpincavy
Date Posted: December 08, 2004 at 12:54 PM
Not really the best amp around. Audiobahn stuff tends to be subpar. Why are you going with three subs, its a sort of hard number to work with amp ans wiring wise, 2 or 4 would be easier to work with.
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Posted By: stevdart
Date Posted: December 08, 2004 at 2:09 PM
As pimpincavy said, using three SVC 4 ohm woofers creates a situation where you will have to find a high quality, high current amp that would perform at the low 1 ohm impedance you will be putting on it. 
Using two of the subs, instead of three, allows for a more useable impedance of 2 ohms. This will allow you to choose from a broad range of amps: class D mono amps or 2 channel amps. The wiring above shows connection to a mono amp. This MTX Thunder amp would fit the bill to power two of those subs, and not run you very much $$.
Posted By: stevdart
Date Posted: December 08, 2004 at 4:20 PM
If you want to use the three subs, you can use this Hifonics mono amp, which will give you a true 415 watts at 1.34 ohms. Your three subs are low power capability woofers, at 150 watts RMS each. You want to shoot for matching power output of an amp to the RMS of the subs. As you can see above, how you connect the subs dictates the ohm load on the amp....which then dictates power output of the amp. Using three subs, you want to shoot for about 500 to 550 watts @ 1 ohm. Using two subs, the number would be 300 watts @ 2 ohms.
Posted By: xandos9
Date Posted: December 08, 2004 at 5:44 PM
What would happen if I used the first second and third channels of a 200X4 RMS amplifier?
Posted By: kfr01
Date Posted: December 08, 2004 at 5:50 PM
The amp is 200x4 at 4 ohms? Well, it'd probably sound great. Might be way more amp than you need though. Which amp are you looking at?
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New Project: 2003 Pathfinder
Posted By: xandos9
Date Posted: December 08, 2004 at 6:11 PM
https://www.hookedontronics.com/show_product_details.jsp?cid=12474
Posted By: xandos9
Date Posted: December 08, 2004 at 6:13 PM
Also would turning the gain up all the way cause a amplifier to over heat?
Posted By: stevdart
Date Posted: December 08, 2004 at 7:32 PM
I don't think your talking about a realistic matchup between amp and sub, quality or power-wise. If you want to use an amp that has 25% more power to the woofer than the woofer will comfortably perform with, you had better start doing research on proper setting of gain using a digital multimeter and professionally recorded test tones. And you didn't post what subs those are, but at 150 watts RMS they are likely not in the top tier of subwoofers available these days. You have to build an enclosure, or separate ones, that is properly mated to the subs. By the time you do that, your choice of subs will be an investment in your system. Since you already have the woofers, but are looking for an amp...it would seem wise to match the amp to the subs. But if you want to start out fresh, think of what your budget for equipment will be. I have given the best advice I could give to you in the previous posts.
Posted By: forbidden
Date Posted: December 08, 2004 at 7:57 PM
Don't go for a multi channel amplifier, a mono amp in this case is going to be the best route. Stevdart recommended a good amp for you. I think Crossfire is also going to have a good little mono sub amp that would do the trick, same with Concept. Meh....there are lots of amps that will do the job for you, just make sure you buy one that will do the task properly.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: kfr01
Date Posted: December 08, 2004 at 8:13 PM
xandos9 wrote:
Also would turning the gain up all the way cause a amplifier to over heat?
This represents a complete misunderstanding of what gain is. Gain is NOT a volume control for your subs! See this page at bcae1.com and educate yourself on what gain is. ------------- New Project: 2003 Pathfinder
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