Hello, again I need some advise from members on this great site to share some of your knowledge.

For x'mas I'm planning on running a 4 channel amp to power up a set of coaxial speakers in the front, and a single 10" sub in a sealed box for my girlfriend's car. In order to do that, I will need to bridge channel 3 & 4 into mono mode for the sub, leaving out the rear speakers stock and unpowered.

The amplifier in question says it will output 150Wrms x 2 ch when in bridge mode.
Does it mean that I will get a total of 300W RMS from the bridged channels to deliver for the sub, or just 150W?
Other question is: The sub I just got was rated a 330W nominal output, what will happen if I under power it by say 30 Watt? will I get distortions?
Here is the equipments, I just bought the sub, the box and the set of coaxials. Thanks, this site and it's members are the greatest!

Sub: Sony XS-L103P5B
http://www.crutchfield.com/S-fSkcBYE...20&I=158XSL103

Amplifier: Performance Teknique ICBM-773
4 Channel power output 60W x 4 Ch
Poweroutput bridged 150W x 2 ch.

I.F.

 

if bridged is 150Wrms x 2, youll have 150 watts rms going to your sub, not 300. that should be about 300 watts max, and that will be just fine for a 330 watt sub. i dont think youre going to find a 330 watt output amp, and the 30 watts difference wont do much at all.

 

Thanks for the quick response stereoneed.
So if my sub's RMS output is 330 watt, powering it around 150 watt rms is fine? I always thought I should match the rms output of the amp with the rms output of the sub? but then again this is the first time I'll be bridging a sub. If it's ok then I'm getting the amp next week Thanks again.
I can't wait to put this system together!!

 

If you are underpowering your sub, then the amp will just have to work harder. If the gain is turned way up to get ample power to the sub, the amp will run hotter and won't last as long. You might be better off getting a 100 x 4 amp. That will give you more than enough power to drive your fronts, and the rears bridged will give you 300 watts rms. The amp will last longer, and you will probably be happier with the results. Also, if you do decide to run a low power amp, make sure you get one with an internal fan and some cooling fins. Overheating=bad. This is especially true if you are running some obscure low end amp off Ebay. At least with a JL audio or Memphis or something you know you are getting at least the rated power that is advertized. The low end brands, and even some popular brands like Audiobahn have a reputation for exaggerating their actual power output.

 

Agreed, plus when you birdge an amp, every time the sub gets signal, it takes away power from the other speakers, which can cause distortion. I would by a separate smaller amp for the speakers, and run your Sub at 150rms. Or, buy a decent mono amp for the sub...

 

Thanks guys for the answers!
The only reason I want to bridge the amp was to save space over putting two amps in the car. It's true having separate amps is always ideal for various reasons. Such as a cooler running amp and better overall sound, but another motive for a single amp is it requires no amp rack and less wiring is involved. Honestly I have no idea where to put the amp(s) in her 05 Honda Civic, with saving the trunk space in mind. The back of the rear seats on the Civic is hollow and provides no platform to mount the amp on. There seems no sufficient space to put it under the front seats. I'm starting to hesitate about amping up the Civic, maybe I'll just switch out her stock speakers first and get her a decent HU that plays MP3 to replace the stock HU.

 

get a 4 channel





then decide what you use more fader or balance



if you never fade than hook 1 channel up right side and one to left side


if you never balance than hook 1 channel up to rear and one to front


the remaining 2 channels bridge to sub



if you like i have a 2005 rockford fosgate punch p8004

125 watts x 4 at 4 ohms
225 watts x 4 @ 2 ohms

 

What's the difference between fader and balance? Sorry but I really don't know about these sort of things....??

 

To fade is to adjust the sound level between "front speakers and rear speakers"....Balance is to adjust the sound level left side to right side of speakers....
Or did I get that backwards? anyway,,,one is front to rear,,,the other is left side speakers to right side speakers....If I use any,,,its only the front/rear adjustment...I never mess with the left/right adjustment...

 

balance is changing signal from left to right
i never balance i always leave signal strength
equal on left as right , meaning i do not want more volume coming from right, or left side, i prefer volume equal on right and left


i do fade sometimes which is front to back , i prefer the ability to have more front stage , and less rear
meaning most of my mids and highs coming from in front of me , and slightly less in the rear , ( for rear fill only ) and i want my fronts to be way more noticeable than my rear

 

They both have to do with balancing the volume between "sides"

fade = front & rear
balance = left & right

Edit: Damn you guys are quick :P