20w from headunit, speakers need 40w ...

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Spockie - 23 Apr 2004 07:49 GMT

20w from headunit, speakers need 40w ...

does this mean if i play the music loud the speakers will become destorted
and be no good after a while?

i am probably going to get an amp in a few days and hook the amp to
speakers behind the head unit so i don't have to take doors and everyhing
off again

i think i might just not drill holes in my trunk though, just let the amp
lay there in the trunk over my stuff i put there

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Kevin Murray - 23 Apr 2004 17:22 GMT

> 20w from headunit, speakers need 40w ...

A speaker rating of 40 watts doesn't mean you need 40. It's the maximum the
manufacturer recommends you drive them with. 20 watts should be fine, try it
first and then buy an amp later if you are dissappointed with the deck power. I
have a feeling that "20watts" might be more like 12-15watts undistorted.
Manufacturers tend to inflate head unit power specs.

> does this mean if i play the music loud the speakers will become destorted
> and be no good after a while?

Playing your music distorted to the point it damages speakers will be noticable
to you. Hopefully you'd turn the volume down until the distortion goes away. In
this case your speakers should be fine and last a long time. Don't forget, you
have untimate control of the output wattage with the volume knob.

> i am probably going to get an amp in a few days and hook the amp to
> speakers behind the head unit so i don't have to take doors and everyhing
> off again

Sounds like a good idea for the front speakers. You should be able to easily run
straight from the amp to the rear speakers though.

> i think i might just not drill holes in my trunk though, just let the amp
> lay there in the trunk over my stuff i put there

Bad idea. Don't leave it free to move around. I suggest installing a thin false
floor in your trunk made of 1/8" plywood so you can mount your amp without
making holes in your car. Make a cut-out in it for spare tire access if
necessary. BTW you are going to install a fuse for this amp right?

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Spockie - 23 Apr 2004 19:41 GMT

>> 20w from headunit, speakers need 40w ...
>
[quoted text clipped - 4 lines]
> might be more like 12-15watts undistorted. Manufacturers tend to
> inflate head unit power specs.

na, max of the speakers is 180
on the back of each speaker it says 40w, like it is suppose to be 40w or
something rms

> Bad idea. Don't leave it free to move around. I suggest installing a
> thin false floor in your trunk made of 1/8" plywood so you can mount
> your amp without making holes in your car. Make a cut-out in it for
> spare tire access if necessary. BTW you are going to install a fuse
> for this amp right?

yeah, i'll install a fuse for the wire to the amp

i am probably going to get one of those 60 dollar jensens

i guess i can look into drilling holes

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MZ - 23 Apr 2004 20:12 GMT

> na, max of the speakers is 180
> on the back of each speaker it says 40w, like it is suppose to be 40w or
> something rms

No, the maximum the speaker can handle is 40 watts if it says 40 watts RMS
on it. Peak ratings essentially refer to what the speaker can handle as an
impulse of energy is delivered to it. Presumably, you listen to music and
not impulses of energy. Everything else Kevin mentioned still holds. The
amount of power a speaker can handle doesn't have much to do with whether or
not 20 watts is sufficient for your needs.

> > Bad idea. Don't leave it free to move around. I suggest installing a
> > thin false floor in your trunk made of 1/8" plywood so you can mount
[quoted text clipped - 7 lines]
>
> i guess i can look into drilling holes

You just don't want to put it in a situation where it will be flopping
around or where a piece of metal (even if it's metal on a coat or something)
can short out some terminals somewhere. If you can even manage to lodge it
somewhere secure without drilling, I suppose that would be good enough.

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Kevin Murray - 23 Apr 2004 20:17 GMT

> >> 20w from headunit, speakers need 40w ...
> >
[quoted text clipped - 8 lines]
> on the back of each speaker it says 40w, like it is suppose to be 40w or
> something rms

This is the maximum average power rating. The 180 max rating is for brief
transients. When I say "brief" I mean in the milliseconds. In my opinion it's a
useless spec. If I were in your shoes and I wanted more than the HU's power
output, I'd go with an 80watt amp. The average power delivered with a music
program would be in the safe range for your speakers.

Decoding manufacturer's power ratings is a challenge in itself.

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