How big an amp do I need?
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=24945
Printed Date: September 11, 2025 at 6:15 AM
Topic: How big an amp do I need?
Posted By: rlsmith
Subject: How big an amp do I need?
Date Posted: January 20, 2004 at 4:04 PM
I have a 2002 Toyota Tundra. I have recently replaced the receiver with a Kenwood and replaced all the speakers with RF's. I have purchased a Q-Logic sub enclosure that mounts under the back seat. It has only enough room for two 8" subs. I have two 8" Rockford 4ohm subs. Can anyone tell me which amp to buy? I don't want to wake the neighbors. I just want good low to moderate sound. Any suggestions? I installed everything myself with no problems. Any reason why I couldn't / shouldn't install the amp? Thanks!
-------------
Ron
Replies:
Posted By: ink_driven
Date Posted: January 20, 2004 at 5:30 PM
What the watt rating of the subs? Are they dual voice coil or single? with out knowing exactly, I would say find the RMS rating for those subs and find an amp that has similar RMS rating. As for doing it yourself, I have always done my own stereo installations and have to say that it is fairly easy to do. Just plan out how your gonna run the wires to hide them. Double check all your connections before putting power to your amp.
Posted By: Teamrf
Date Posted: January 20, 2004 at 5:51 PM
Go grab you 150 watt amp that would do you just fine.
-------------
~The Rookie~
Rookie of the year that is...
Don't let the smoke out of your equiptment..it doesn't go back in.
Posted By: xTimx
Date Posted: January 20, 2004 at 7:01 PM
depending on the subs. i would get a 300 watt amp. that way you'll have more power to your subs and cleaner sound w/o the worry of dmging your subs in the long run. and still you can turn the gain up and down where ever your going. say your in the neighbor hood and you dont wanna wake the neighbors, turn the gain down, but when your headed out on the road or some where, crank them up and enjoy your music! :)
Posted By: customsuburb
Date Posted: January 20, 2004 at 7:14 PM
If you have Rockfords 8" Punch Z or HE then I would reccomend Rockford Fosgates Punch 301M amp and wire your two subs in parrallel to get 300 watts RMS at 2 ohms. https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=130&I=575301M&o=m&a=0&cc=01&avf=N 
If you have HE2's or HX2's then I would reccomend the Rockford Power 351S amp which would give you just a little bit more power for your subs at 4 ohms bridged (350 watts RMS). https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=110&I=575351S&o=m&a=0&cc=01&avf=N I would wire them in Parrallel also :
Posted By: rlsmith
Date Posted: January 20, 2004 at 8:58 PM
customsuburb wrote:
If you have Rockfords 8" Punch Z or HE then I would reccomend Rockford Fosgates Punch 301M amp and wire your two subs in parrallel to get 300 watts RMS at 2 ohms. https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=130&I=575301M&o=m&a=0&cc=01&avf=N
If you have HE2's or HX2's then I would reccomend the Rockford Power 351S amp which would give you just a little bit more power for your subs at 4 ohms bridged (350 watts RMS). https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=110&I=575351S&o=m&a=0&cc=01&avf=N I would wire them in Parrallel also :
------------- Ron
Posted By: rlsmith
Date Posted: January 20, 2004 at 9:01 PM
customsuburb wrote:
If you have Rockfords 8" Punch Z or HE then I would reccomend Rockford Fosgates Punch 301M amp and wire your two subs in parrallel to get 300 watts RMS at 2 ohms. https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=130&I=575301M&o=m&a=0&cc=01&avf=N
If you have HE2's or HX2's then I would reccomend the Rockford Power 351S amp which would give you just a little bit more power for your subs at 4 ohms bridged (350 watts RMS). https://www.crutchfield.com/cgi-bin/S-EL41FJeiRzg/ProdView.asp?s=0&c=3&g=110&I=575351S&o=m&a=0&cc=01&avf=N I would wire them in Parrallel also :
Great info! I have the Punch Z subs. That's all that will fit the enclosure. What about the 351M? That would give me the remote adjustment. I can pick one up on the web for $135 ------------- Ron
Posted By: customsuburb
Date Posted: January 21, 2004 at 4:47 PM
I Think that the 351M would be too much power for your punch Zs. They only like 150 watts max continuous and the Rockford amp would put out at least 350 watts in 2 ohm mono. I wouldnt reccomend. I think Rockford amps are underrated also. I would just go with the Punch 301M. If you really want the power 350M then be really careful with your gain control and bass boost. You could blow those subs easily. If you plan on upgrading soon after this anyway to bigger subs it might not be a prob though. Then you wouldnt have to upgrade your amp probobly. 
Posted By: rlsmith
Date Posted: January 21, 2004 at 5:00 PM
Is it just a matter of wiring? Can I wire them so they don't put out so much power
-------------
Ron
Posted By: rlsmith
Date Posted: January 21, 2004 at 6:40 PM
OK Now I am worried. I ordered a 351S because I wanted the remote volume switch and I wanted to be able to power the front speakers if I decide to. Did I screw up? Can I not use the 351S with RFZ3408 speakers? The box says they are rated at 150/400 rms. If I can use the amp, How would I wire it to make sure I didn't feed to much power to the speakers? Thanks for your help! ------------- Ron
Posted By: forbidden
Date Posted: January 21, 2004 at 7:03 PM
Relax, you will be OK. While this amp is not a 100% perfect match, you can use it for now and it will do a good job for you. Just because the speakers say 150 watts does not mean that they have to have that much power to operate properly, matter of fact if they are in a ported enclosure they will handle even less. The worst case scenario for this amp is that it will produce 90w x 2 @ 4ohms, count on it producing more. If in the future it is not big enough for your subs or you buy new subs, you can now use this amp to drive a nice set of front speakers and get a bigger amp for the subs. Money not wasted, but just moved around to another task. ------------- Top Secret, I can tell you but then my wife will kill me.
Posted By: customsuburb
Date Posted: January 21, 2004 at 7:23 PM
Just remember to watch your setting on the gain and bass boost control. Otherwise you'll be fine like forbidden said.
Posted By: The Distortion
Date Posted: January 22, 2004 at 7:45 AM
FWIW I put a Image Dynamics 8" sub on a RF 550S bridged, never had any problem
just turn the gains down on your amp, remember that that is not a volume control, best bet is to just disconnect that thing...you'll be fine.
Posted By: rlsmith
Date Posted: January 22, 2004 at 7:49 AM
An RF550S? I can't find that one. What was it's bridged rating? Thanks! Ron ------------- Ron
Posted By: The Distortion
Date Posted: January 22, 2004 at 7:51 AM
550wrms yet the birthsheet on it was 592
|