Hi there,

I appologise as I am a bit of a beginner in the car audio format. I
am setting up a modest speaker set up for my van, and do not seem to
be doing very well. I have an old second hand (but supposed to be
working fine) Kenwood KAC 846 amp, this is 4x50w a channel and 125w
bridged. I am hoping to run a 12 inch sub off the bridged 125w
channel set with a low pass filter, and two 6'9;s in high pass of the
two remaining 50w channels. I wired it all up and got the setting on
the amp right including gain and filters etc. However the Alpine 35W
RMS 6'9's sound terrible, they sound all scratchy and the sound is
really distorted and unpleasant at medium to high volumes. I know
they have 50w going into them but they are only being run at medium
levels and the gain is set real low. The speakers sound fine when
plugged in direct to the headunit, a much clearer quality sound. But
I want to run them off the amp due to the requirements in the camper
van. Now here is the question, I have wired the amp up from the power
supply feed in the stereo loom, jumping a connection of the iso block
at the back of the stereo, not straight to the battery and the amp is
earthed the same way. Could it be that as I have not created a sole
earth and live feed straight from the battery there is some sort of
interferance that is messing with the sound. This problem exists
whether the engine is running or not. Or is it more likely that the
amp is shot and I need a new one.

Please help as I dont understand why it sounds so bad.

Cheers

Trev

you should use atleast an 8 guage power wire for the amp run directly to the
battery. the ground should be the same size and run to a clean metal point
with a bolt.


"Trev Worsey" wrote in message
om...
Hi there,

I appologise as I am a bit of a beginner in the car audio format. I
am setting up a modest speaker set up for my van, and do not seem to
be doing very well. I have an old second hand (but supposed to be
working fine) Kenwood KAC 846 amp, this is 4x50w a channel and 125w
bridged. I am hoping to run a 12 inch sub off the bridged 125w
channel set with a low pass filter, and two 6'9;s in high pass of the
two remaining 50w channels. I wired it all up and got the setting on
the amp right including gain and filters etc. However the Alpine 35W
RMS 6'9's sound terrible, they sound all scratchy and the sound is
really distorted and unpleasant at medium to high volumes. I know
they have 50w going into them but they are only being run at medium
levels and the gain is set real low. The speakers sound fine when
plugged in direct to the headunit, a much clearer quality sound. But
I want to run them off the amp due to the requirements in the camper
van. Now here is the question, I have wired the amp up from the power
supply feed in the stereo loom, jumping a connection of the iso block
at the back of the stereo, not straight to the battery and the amp is
earthed the same way. Could it be that as I have not created a sole
earth and live feed straight from the battery there is some sort of
interferance that is messing with the sound. This problem exists
whether the engine is running or not. Or is it more likely that the
amp is shot and I need a new one.

Please help as I dont understand why it sounds so bad.

Cheers

Trev

Check the phase.

"Trev Worsey" wrote in message
om...
Hi there,

I appologise as I am a bit of a beginner in the car audio format. I
am setting up a modest speaker set up for my van, and do not seem to
be doing very well. I have an old second hand (but supposed to be
working fine) Kenwood KAC 846 amp, this is 4x50w a channel and 125w
bridged. I am hoping to run a 12 inch sub off the bridged 125w
channel set with a low pass filter, and two 6'9;s in high pass of the
two remaining 50w channels. I wired it all up and got the setting on
the amp right including gain and filters etc. However the Alpine 35W
RMS 6'9's sound terrible, they sound all scratchy and the sound is
really distorted and unpleasant at medium to high volumes. I know
they have 50w going into them but they are only being run at medium
levels and the gain is set real low. The speakers sound fine when
plugged in direct to the headunit, a much clearer quality sound. But
I want to run them off the amp due to the requirements in the camper
van. Now here is the question, I have wired the amp up from the power
supply feed in the stereo loom, jumping a connection of the iso block
at the back of the stereo, not straight to the battery and the amp is
earthed the same way. Could it be that as I have not created a sole
earth and live feed straight from the battery there is some sort of
interferance that is messing with the sound. This problem exists
whether the engine is running or not. Or is it more likely that the
amp is shot and I need a new one.

Please help as I dont understand why it sounds so bad.

Cheers

Trev

Ok, as a follow up i spent all last night plumbing in an 8SWG power
line direct to the battery and earthed the amp and amp body using 8SWG
to the same earth on the van floor (scraped off the paint and sanded
the spot to get a good connection). Checked the phase which was
indeed out. Sorted all this and it now sounds 10x better - BUT still
not right, even though the KAC 846 is set up right the high end is
scratchy and fuzzy and the low end is a bit loose (we are not talking
audiophile paranioa here, it is obviously wrong). The speakers handle
the headunit amp fine so they are good enough for the job. The
interconnects are good quality £20. I am stumped, I am guessing that
the problem is the amp itself...

Bugger..