"Arny Krueger" <arnyk@[EMAIL PROTECTED]
> wrote in message
news:Gc2dnWSGua6_1b3VnZ2dnUVZ_q-jnZ2d@[EMAIL PROTECTED]
> "Neil Green" <nrgreenNOT@[EMAIL PROTECTED]
> wrote in
> message
> news:481f9e14$0$17508$afc38c87@[EMAIL PROTECTED]
>
>> My son bought some 6" Kenwood speakers from a local
>> shop, not cheapies, and we installed them on the
>> rear
>> parcel shelf of his car on Sunday.
>
> A sort of a classic kind of installation.
>
>> If we crank the volume (to around 75%) and bass up
>> the
>> distortion is really severe.
>
>
> Either the amplifier is clipping or the speakers are
> running out of stroke, or there is some kind of
> parasitic vibration.
>
> What can you tell us that will help us decide which
> one it is?
Nothing really, I have little knowledge of these
things, but the distortion is coming from the speakers
themselves in the form of a coarse vibration so I
doubt it has anything to do with the amplifier.
>
>> You can see the cones bouncing up and down
>
> That's normal, to a point.
>
>> and they
>> make a vibrating sound which is very unpleasant so
>> he
>> has to either lower the volume of reduce the bass
>> to
>> eliminate this noise.
>
> Sounds like a parasitic vibration, possibly caused
> by bad mechanical installation.
They are screwed down tight to the steel parcel shelf
using a small amount of 1.6mm double sided tape at
each fixing point, or which there are four for each
speaker.
I can't see how they could vibrate against the body.
>
>> What I'd like to know is if this effect is just a
>> limitation of 6" speakers
>
> While 6" speakers are not the be-all or end-all, a
> pair of good ones can be pretty impressive in the
> small confines of a car. BTW, they are probably 6
> 1/2", as that is a near standard size.
>
>> or whether the speakers themselves aren't up to par
>
> Without more details, how would anybody know? Model
> number????
Kenwood KFC - M1628A
Not top of the range, but not rubbish, or so the
salesman assured my son.
>
>> or if there's any way of
>> reducing this distortion to acceptable levels.
>
> Turn them down. ;-)
Looks like he will.
>
>> Would housing the speakers in boxes placed above
>> the
>> shelf help?
>
> Probably not. The trunk makes up a wonderful large
> enclosure for trapping the back wave of the right
> speaker drivers. With the right speakers, it can
> work very well.
>
>
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