Speaker/Head unit RMS question

Bhikku

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I recently replaced by stock speakers with some rockford fosgate ones. 40 watt in the front, 60 watt in the back.

Tested them individually as i wired them, and they worked so it doesn't appear to be an issue with the installation.

When i power them up the stereo it makes a buzzing sound in one speaker and none in the rest, it will go away if i turn the volume up high enough and start playing music. although the front are muted and sound like s**t.

I believe this is due to the head unit, which is 52x4 just not giving out enough power.

I'm fine with replacing the head unit, as the aux in doesn't work. So if i do that what wattage should i look for? 60x4?

Or is there a way i can wire in an amp to the head unit to give it the extra juice?

Thanks :>
 

Bhikku

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So from what i've been reading it might be better in the long run and cheap to run a 60x4 RMS 4 channel amp and connect it to the head unit. I'm a little lost on the specifics on the wiring and connections but am still researching it...

also if my head unit is 52x4 and i add an amp at lets say 50x4, am i then running 104x4, or does it just run off the amps wattage?
 


xHanzJay

Lulzaflopter
sounds more like a ground problem to me. did you use the stock ground, or ground it to the frame? (buzzing) maybe just a bad headunit.
rms of the speakers shouldn't matter, 50x4 is the most common rms for a headunit and should be able to power any replacement car speaker. it just won't be able to use the full potential of the speaker (you'll get clipping before the speaker reaches it's peak output).

also if my head unit is 52x4 and i add an amp at lets say 50x4, am i then running 104x4, or does it just run off the amps wattage?

no, you'd not use the headunit power. so you'd only be using whatever the amp power is.

i have a 5 channel, 75x4 250x1@ 4ohm
currently i'm using the amp to power my rear speakers, that's 75x2, and using the headunit to power the front speakers (that's 50x2) (and 250x1 to my subs, they are cheap low watt subs)

but if i actually stopped being lazy and hooked up the front speakers to the amp it would be 75x4, and the 50x4 from the headunit would just go un-used.

then again i might just bridge the rear and run 300x2 500x1
 

Bhikku

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sounds more like a ground problem to me. did you use the stock ground, or ground it to the frame? (buzzing) maybe just a bad headunit.
rms of the speakers shouldn't matter, 50x4 is the most common rms for a headunit and should be able to power any replacement car speaker. it just won't be able to use the full potential of the speaker (you'll get clipping before the speaker reaches it's peak output).
I just wired the speakers to the stock + - wires

no, you'd not use the headunit power. so you'd only be using whatever the amp power is.

i have a 5 channel, 75x4 250x1@ 4ohm
currently i'm using the amp to power my rear speakers, that's 75x2, and using the headunit to power the front speakers (that's 50x2) (and 250x1 to my subs, they are cheap low watt subs)

but if i actually stopped being lazy and hooked up the front speakers to the amp it would be 75x4, and the 50x4 from the headunit would just go un-used.

then again i might just bridge the rear and run 300x2 500x1

gotcha, thanks for clearing that up
 


xHanzJay

Lulzaflopter
to the negative stock wiring
that's a no-no. you need to find a bare piece of metal and bolt it to the body using an eyelet thinggy that i can't think of the name of. (its round and you can put a bolt through it, it crimps to the wire).
you may have to extend your ground wire to get it to reach the body. take the stock wire with some electrical tape.
 

Bhikku

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that's a no-no. you need to find a bare piece of metal and bolt it to the body using an eyelet thinggy that i can't think of the name of. (its round and you can put a bolt through it, it crimps to the wire).
you may have to extend your ground wire to get it to reach the body. take the stock wire with some electrical tape.
oh wow i did not know that. why could the stock speakers use the stock ground? less wattage?
 

HeX

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If your issues is only at one speaker, then I'm inclined to believe its an issue at that one speaker. Perhaps something is loose near the cone, such as speaker wire slack. Check for solid connection at the speaker wire terminals. Play with the volume with the speaker in front of you.

Its far less likely that the issue is the headunit. But to be on the safe side, also check the wiring at the headunit harness for that specific speaker.
 

Bhikku

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If your issues is only at one speaker, then I'm inclined to believe its an issue at that one speaker. Perhaps something is loose near the cone, such as speaker wire slack. Check for solid connection at the speaker wire terminals. Play with the volume with the speaker in front of you.

Its far less likely that the issue is the headunit. But to be on the safe side, also check the wiring at the headunit harness for that specific speaker.
One speaker will make the buzzing sound at love volume and when the car is shut off, but both front speakers have little to no sound output
 

Bhikku

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here's a question: how did the speakers work BEFORE you installed the headunit?
The head unit was in there from PO with stock speakers, stock speakers worked correctly. Tested speakers when i installed them, it only started doing the buzzing thing and low output to fronts after i hooked up the fourth LR speaker.
 

HeX

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The head unit was in there from PO with stock speakers, stock speakers worked correctly. Tested speakers when i installed them, it only started doing the buzzing thing and low output to fronts after i hooked up the fourth LR speaker.
Then something was connected incorrectly. Check all the connections at the radio harness. Also check the radio EQ. Perhaps a setting has the speaker output set low. What radio is it?
 

Bhikku

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checked all the balances and eq stuff, everything is at normal. head unit is a low end sony one, nothing special. i suppose it's possible something is off with the connections, i double checked them against a list and everything appeared to line up, but i'll double check when i get off work.
 

Bhikku

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I believe i may have solved my issue. the back end of the speaker where the magnet is seems to have been making contact with a part of the door frame that was metal and grounding out. i discovered that as i was taking off the speaker frame cover that if i pressed on the screwdriver it would make the buzzing sound.

i insulated the exposed metal on the door frame and tightened everything back up and the speakers appeared to sound normal!

I'll monitor it for sound quality and buzzing for the next little while, but i'm fairly certain this was what was causing my issue.

thanks for everyone's input and help on this, it is much appreciated :>
 


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