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Neil Green[_2_] Neil Green[_2_] is offline
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Default 6" Kenwood speakers

Hi all
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.
If we crank the volume (to around 75%) and bass up the
distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way of
reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above the
shelf help?
Thanks
Neil.


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Matt Ion Matt Ion is offline
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Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass up the
distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way of
reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above the
shelf help?
Thanks
Neil.


What sort of car? What sort of parcel shelf? Without the speakers
being mounted in a solid baffle, you'll lose some bass production simply
through cancellation.

Most 6" speakers won't produce a lot of bass to begin with, but proper
mounting will produce a better bass response and you won't need to crank
the bass knob as much.
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Neil Green[_2_] Neil Green[_2_] is offline
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Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass up
the distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way
of reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above
the shelf help?
Thanks
Neil.


What sort of car? What sort of parcel shelf?
Without the speakers being mounted in a solid
baffle, you'll lose some bass production simply
through cancellation.


It's a Nissan sedan, the parcel shelf has cutouts in
the steel for the original speakers which suit the 6"
Kenwoods.
It also has a fabric covered composite board insert
over the steel shelf.
I thouhjt I could make some MDF boxes and mount them
on top of the shelf, but if that doesn't reduce the
distortion it will be a waste of time.


Most 6" speakers won't produce a lot of bass to
begin with, but proper mounting will produce a
better bass response and you won't need to crank the
bass knob as much.


So is it worth making the boxes?
I was thinking 12mm MDF, and paint them matt black.


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Matt Ion Matt Ion is offline
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Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass up
the distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way
of reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above
the shelf help?
Thanks
Neil.

What sort of car? What sort of parcel shelf?
Without the speakers being mounted in a solid
baffle, you'll lose some bass production simply
through cancellation.


It's a Nissan sedan, the parcel shelf has cutouts in
the steel for the original speakers which suit the 6"
Kenwoods.
It also has a fabric covered composite board insert
over the steel shelf.
I thouhjt I could make some MDF boxes and mount them
on top of the shelf, but if that doesn't reduce the
distortion it will be a waste of time.

Most 6" speakers won't produce a lot of bass to
begin with, but proper mounting will produce a
better bass response and you won't need to crank the
bass knob as much.


So is it worth making the boxes?
I was thinking 12mm MDF, and paint them matt black.


Those type of speakers are generally designed for an "infinite baffle"
type setup, meaning they're not intended to have a box behind them.
It'll work, and probably get rid of most of the "flapping" of the cones,
but it won't really give you much better bass response simply by the
lack of air behind the speakers. (see
http://www.the12volt.com/caraudio/boxes1.asp)

The problem you have is that there are probably other cutouts in that
steel deck, and the cardboard panel (since that's really what it is,
just stiff cardboard) over it is effectively "transparent" to most of
the bass frequencies, so the mounting location has limited usefulness as
a baffle. The ideal solution for using those speakers would be to build
a more solid deck to replace or complement the cardboard insert. Even
1/4" (6mm) MDF would be a significant improvement.

One other thing you want to check is the speaker phase - make sure both
+ terminals in the wiring are connected to the appropriate + terminal on
each speaker. If the speakers are out of phase with each other (+/-
reversed), the two cones will be working against each other and
canceling bass that way.

Ultimately, you want a separate sub and amp to get any sort of decent
bass - 6" speakers like that simply aren't designed to move a lot of
air, and most decks don't produce the power to move them very much.
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Neil Green[_2_] Neil Green[_2_] is offline
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Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass
up the distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way
of reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above
the shelf help?
Thanks
Neil.
What sort of car? What sort of parcel shelf?
Without the speakers being mounted in a solid
baffle, you'll lose some bass production simply
through cancellation.


It's a Nissan sedan, the parcel shelf has cutouts
in the steel for the original speakers which suit
the 6" Kenwoods.
It also has a fabric covered composite board insert
over the steel shelf.
I thouhjt I could make some MDF boxes and mount
them on top of the shelf, but if that doesn't
reduce the distortion it will be a waste of time.

Most 6" speakers won't produce a lot of bass to
begin with, but proper mounting will produce a
better bass response and you won't need to crank
the bass knob as much.


So is it worth making the boxes?
I was thinking 12mm MDF, and paint them matt black.


Those type of speakers are generally designed for an
"infinite baffle" type setup, meaning they're not
intended to have a box behind them. It'll work, and
probably get rid of most of the "flapping" of the
cones, but it won't really give you much better bass
response simply by the lack of air behind the
speakers. (see
http://www.the12volt.com/caraudio/boxes1.asp)


It's the "flapping" as you call it that's the major
concern for my son, and not the bass response as such.
I could leave the bootom of the box open and place it
over the cutout with some cloth or similar to restrict
the air flow to the back of the cones.
Would that work?


The problem you have is that there are probably
other cutouts in that steel deck, and the cardboard
panel (since that's really what it is, just stiff
cardboard) over it is effectively "transparent" to
most of the bass frequencies, so the mounting
location has limited usefulness as a baffle. The
ideal solution for using those speakers would be to
build a more solid deck to replace or complement the
cardboard insert. Even 1/4" (6mm) MDF would be a
significant improvement.


Easily done.


One other thing you want to check is the speaker
phase - make sure both + terminals in the wiring are
connected to the appropriate + terminal on each
speaker. If the speakers are out of phase with each
other (+/- reversed), the two cones will be working
against each other and canceling bass that way.


Checked that with a meter, all OK.


Ultimately, you want a separate sub and amp to get
any sort of decent bass - 6" speakers like that
simply aren't designed to move a lot of air, and
most decks don't produce the power to move them very
much.


I thought as much, but all he really wants is a nice
clean sound without the rumbling.




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Matt Ion Matt Ion is offline
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Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass
up the distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just a
limitation of 6" speakers or whether the speakers
themselves aren't up to par or if there's any way
of reducing this distortion to acceptable levels.
Would housing the speakers in boxes placed above
the shelf help?
Thanks
Neil.
What sort of car? What sort of parcel shelf?
Without the speakers being mounted in a solid
baffle, you'll lose some bass production simply
through cancellation.
It's a Nissan sedan, the parcel shelf has cutouts
in the steel for the original speakers which suit
the 6" Kenwoods.
It also has a fabric covered composite board insert
over the steel shelf.
I thouhjt I could make some MDF boxes and mount
them on top of the shelf, but if that doesn't
reduce the distortion it will be a waste of time.

Most 6" speakers won't produce a lot of bass to
begin with, but proper mounting will produce a
better bass response and you won't need to crank
the bass knob as much.
So is it worth making the boxes?
I was thinking 12mm MDF, and paint them matt black.

Those type of speakers are generally designed for an
"infinite baffle" type setup, meaning they're not
intended to have a box behind them. It'll work, and
probably get rid of most of the "flapping" of the
cones, but it won't really give you much better bass
response simply by the lack of air behind the
speakers. (see
http://www.the12volt.com/caraudio/boxes1.asp)


It's the "flapping" as you call it that's the major
concern for my son, and not the bass response as such.
I could leave the bootom of the box open and place it
over the cutout with some cloth or similar to restrict
the air flow to the back of the cones.
Would that work?


Well the "flapping" is likely a result of attempting to get more bass
out of the speakers... solve the bass issue, and the flapping should
take care of itself A backless box over the cutout really doesn't
help the problem, as you still get the "leakage" through other cutouts
in the metal.

The problem you have is that there are probably
other cutouts in that steel deck, and the cardboard
panel (since that's really what it is, just stiff
cardboard) over it is effectively "transparent" to
most of the bass frequencies, so the mounting
location has limited usefulness as a baffle. The
ideal solution for using those speakers would be to
build a more solid deck to replace or complement the
cardboard insert. Even 1/4" (6mm) MDF would be a
significant improvement.


Easily done.


I'd say that's your first stop then. If possible, use the cardboard
insert as a template to ensure your new insert covers the entire rear
deck - remember, the ultimate goal is no places for air movement between
the top and bottom of the shelf.

One other thing you want to check is the speaker
phase - make sure both + terminals in the wiring are
connected to the appropriate + terminal on each
speaker. If the speakers are out of phase with each
other (+/- reversed), the two cones will be working
against each other and canceling bass that way.


Checked that with a meter, all OK.


A meter won't tell you if the polarity is right. The speakers will be
labeled, the positive terminal probably marked with red and maybe wider
than the other. If you're using the factory wiring, one will PROBABLY
have a larger/wider terminal lug on it. However, if they're the same
size or have had new connectors spliced on to them, you may need to dig
a little deeper.

Is this car running the stock deck as well, or is it an aftermarket deck?

Ultimately, you want a separate sub and amp to get
any sort of decent bass - 6" speakers like that
simply aren't designed to move a lot of air, and
most decks don't produce the power to move them very
much.


I thought as much, but all he really wants is a nice
clean sound without the rumbling.


A basic sealed box with an 8" sub will give him nice clean bottom end
without need of massive amounts of amp power. The bass can then be
filtered out of the 6s.
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Neil Green[_2_] Neil Green[_2_] is offline
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Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
"Matt Ion" wrote in message
...
Neil Green wrote:
Hi all
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.
If we crank the volume (to around 75%) and bass
up the distortion is really severe.
You can see the cones bouncing up and down 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.
What I'd like to know is if this effect is just
a limitation of 6" speakers or whether the
speakers themselves aren't up to par or if
there's any way of reducing this distortion to
acceptable levels.
Would housing the speakers in boxes placed
above the shelf help?
Thanks
Neil.
What sort of car? What sort of parcel shelf?
Without the speakers being mounted in a solid
baffle, you'll lose some bass production simply
through cancellation.
It's a Nissan sedan, the parcel shelf has cutouts
in the steel for the original speakers which suit
the 6" Kenwoods.
It also has a fabric covered composite board
insert over the steel shelf.
I thouhjt I could make some MDF boxes and mount
them on top of the shelf, but if that doesn't
reduce the distortion it will be a waste of time.

Most 6" speakers won't produce a lot of bass to
begin with, but proper mounting will produce a
better bass response and you won't need to crank
the bass knob as much.
So is it worth making the boxes?
I was thinking 12mm MDF, and paint them matt
black.
Those type of speakers are generally designed for
an "infinite baffle" type setup, meaning they're
not intended to have a box behind them. It'll
work, and probably get rid of most of the
"flapping" of the cones, but it won't really give
you much better bass response simply by the lack
of air behind the speakers. (see
http://www.the12volt.com/caraudio/boxes1.asp)


It's the "flapping" as you call it that's the major
concern for my son, and not the bass response as
such.
I could leave the bootom of the box open and place
it over the cutout with some cloth or similar to
restrict the air flow to the back of the cones.
Would that work?


Well the "flapping" is likely a result of attempting
to get more bass out of the speakers... solve the
bass issue, and the flapping should take care of
itself A backless box over the cutout really
doesn't help the problem, as you still get the
"leakage" through other cutouts in the metal.


I follow.


The problem you have is that there are probably
other cutouts in that steel deck, and the
cardboard panel (since that's really what it is,
just stiff cardboard) over it is effectively
"transparent" to most of the bass frequencies, so
the mounting location has limited usefulness as a
baffle. The ideal solution for using those
speakers would be to build a more solid deck to
replace or complement the cardboard insert. Even
1/4" (6mm) MDF would be a significant improvement.


Easily done.


I'd say that's your first stop then. If possible,
use the cardboard insert as a template to ensure
your new insert covers the entire rear deck -
remember, the ultimate goal is no places for air
movement between the top and bottom of the shelf.


A job for the weekend, thanks for the advice.


One other thing you want to check is the speaker
phase - make sure both + terminals in the wiring
are connected to the appropriate + terminal on
each speaker. If the speakers are out of phase
with each other (+/- reversed), the two cones will
be working against each other and canceling bass
that way.


Checked that with a meter, all OK.


A meter won't tell you if the polarity is right.


Mine does.
A minus sign displays if the polarity is wrong as you
measure the voltage.
All OK.

The speakers will be
labeled, the positive terminal probably marked with
red and maybe wider than the other. If you're using
the factory wiring, one will PROBABLY have a
larger/wider terminal lug on it. However, if
they're the same size or have had new connectors
spliced on to them, you may need to dig a little
deeper.

Is this car running the stock deck as well, or is it
an aftermarket deck?


The stock deck was a cassette player (it's a '92 model
car).
We put a Pioneer head unit in, can't remember the
model but all the reviews were good.


Ultimately, you want a separate sub and amp to get
any sort of decent bass - 6" speakers like that
simply aren't designed to move a lot of air, and
most decks don't produce the power to move them
very much.


I thought as much, but all he really wants is a
nice clean sound without the rumbling.


A basic sealed box with an 8" sub will give him nice
clean bottom end without need of massive amounts of
amp power. The bass can then be filtered out of the
6s.


No room for a sub I'm afraid, he'll have to live with
less bass or maybe beef up the 7 x 5's in the front
doors and fade more to the front.
Either way he'll have to live with the limitations of
the system.
Thanks very much for your time.


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Arny Krueger Arny Krueger is offline
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Posts: 17,262
Default 6" Kenwood speakers

"Neil Green" wrote in message
u

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?

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.

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????

or if there's any way of
reducing this distortion to acceptable levels.


Turn them down. ;-)

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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bob wald bob wald is offline
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Posts: 384
Default 6" Kenwood speakers

first the rear speakers are for the rear passengers.
if you trying to get them to sound great for the front drivers...lol
next a box will only improve the bass....nothing else.
next 6'' isnt suppose to give good bass.
this is only the tip. but i am alil tired.
******all the other people are salesmen.***** trying to sell services or
equipment.
i am not.

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Matt Ion Matt Ion is offline
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Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:

One other thing you want to check is the speaker
phase - make sure both + terminals in the wiring
are connected to the appropriate + terminal on
each speaker. If the speakers are out of phase
with each other (+/- reversed), the two cones will
be working against each other and canceling bass
that way.
Checked that with a meter, all OK.

A meter won't tell you if the polarity is right.


Mine does.
A minus sign displays if the polarity is wrong as you
measure the voltage.
All OK.


Umm... what voltage are you measuring?

The signal coming out of the deck is AC; the signal phase has to be the
same in both speakers. There is no "right" or "wrong" polarity as such,
they just have to be the same. A DC meter won't give you a meaningful
reading.

Is this car running the stock deck as well, or is it
an aftermarket deck?


The stock deck was a cassette player (it's a '92 model
car).
We put a Pioneer head unit in, can't remember the
model but all the reviews were good.


That makes it a little easier then, because you can check the polarity
of the connections to the deck, then confirm them at the speaker end.
If you used the factory speaker wiring, just follow the wiring color
codes and make sure the + and - outputs on the deck properly match the
terminals on the speakers.

A basic sealed box with an 8" sub will give him nice
clean bottom end without need of massive amounts of
amp power. The bass can then be filtered out of the
6s.


No room for a sub I'm afraid, he'll have to live with
less bass or maybe beef up the 7 x 5's in the front
doors and fade more to the front.
Either way he'll have to live with the limitations of
the system.
Thanks very much for your time.


There's always room for a sub Build a baffle out of 3/4" MDF, put it
behind the back seat, and mount a freeair sub in it, no box required

5x7s won't give you significantly more bass than 6" rounds, BTW. Bass
response is a factor of the amount of air moved, and that has two
factors when it comes to the speakers: cone surface area, and excursion.
Not accounting for the tapered shape of the cone itself or differences
in surround width, a 5x7 speaker nominally has about 27.5 sq. in. of
surface area; a 6.5" round speaker has 44 sq. in. of surface area. In
other words, excursion notwithstanding, a 6.5" round speaker moves
almost twice as much as a 5x7.



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Neil Green[_2_] Neil Green[_2_] is offline
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Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:

One other thing you want to check is the speaker
phase - make sure both + terminals in the wiring
are connected to the appropriate + terminal on
each speaker. If the speakers are out of phase
with each other (+/- reversed), the two cones
will be working against each other and canceling
bass that way.
Checked that with a meter, all OK.
A meter won't tell you if the polarity is right.


Mine does.
A minus sign displays if the polarity is wrong as
you measure the voltage.
All OK.


Umm... what voltage are you measuring?

The signal coming out of the deck is AC; the signal
phase has to be the same in both speakers. There is
no "right" or "wrong" polarity as such, they just
have to be the same. A DC meter won't give you a
meaningful reading.


The AC bit is news to me, I was under the impression
that the current to the speakers was DC, but as you
can probably tell I'm more or less ignorant in these
matters.
Anyway, the meter showed a minus sign one way and not
the other, and I connected the two speakers
accordingly. (The connectors on the loom of the car
were both the same size so that was no help, replaced
one of them at each speaker with a smaller one)


Is this car running the stock deck as well, or is
it an aftermarket deck?


The stock deck was a cassette player (it's a '92
model car).
We put a Pioneer head unit in, can't remember the
model but all the reviews were good.


That makes it a little easier then, because you can
check the polarity of the connections to the deck,
then confirm them at the speaker end. If you used
the factory speaker wiring, just follow the wiring
color codes and make sure the + and - outputs on the
deck properly match the terminals on the speakers.


My son actually had them written down (good boy!) and
they tallied with how we had the speakers wired so
it's all good as far as that goes.


A basic sealed box with an 8" sub will give him
nice clean bottom end without need of massive
amounts of amp power. The bass can then be
filtered out of the 6s.


No room for a sub I'm afraid, he'll have to live
with less bass or maybe beef up the 7 x 5's in the
front doors and fade more to the front.
Either way he'll have to live with the limitations
of the system.
Thanks very much for your time.


There's always room for a sub Build a baffle out
of 3/4" MDF, put it behind the back seat, and mount
a freeair sub in it, no box required


The rear seats fold forward so there's nothing to
mount a sub on, and my son needs the folding seats to
stow golf clubs..


5x7s won't give you significantly more bass than 6"
rounds, BTW. Bass response is a factor of the
amount of air moved, and that has two factors when
it comes to the speakers: cone surface area, and
excursion. Not accounting for the tapered shape of
the cone itself or differences in surround width, a
5x7 speaker nominally has about 27.5 sq. in. of
surface area; a 6.5" round speaker has 44 sq. in. of
surface area. In other words, excursion
notwithstanding, a 6.5" round speaker moves almost
twice as much as a 5x7.


OK, so we make up an MDF parcel shelf and kill a
little of the bass, that's OK.
The system sounds fine apart from the bass distortion
so I'll tell him to go easy.
Once again, thanks very much for your time and
patience.


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Neil Green[_2_] Neil Green[_2_] is offline
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Default 6" Kenwood speakers


"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message
u

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.




  #13   Report Post  
Posted to rec.audio.car
Arny Krueger Arny Krueger is offline
external usenet poster
 
Posts: 17,262
Default 6" Kenwood speakers

"Neil Green" wrote in message

"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message
u

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.


You mean screw + tape, right?

I can't see how they could vibrate against the body.


Maybe the shelf itself, or a stiff covering...

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


I get 6.25 inch nominal diameter.

They are a $50/pair class 3-way, which I would not expect too much of.

Not top of the range, but not rubbish, or so the
salesman assured my son.


I would say, towards the bottom of the market segment.

or if there's any way of
reducing this distortion to acceptable levels.


Turn them down. ;-)


Looks like he will.


Rarely fails! ;-)

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.


I notice that Kenwood recommends using an angled adaptor with these
speakers, in a rear parcel shelf application:

http://india.kenwood.com/products/ca.../features.html



  #14   Report Post  
Posted to rec.audio.car
Matt Ion Matt Ion is offline
external usenet poster
 
Posts: 420
Default 6" Kenwood speakers

Arny Krueger wrote:

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.


You mean screw + tape, right?


Ugh... there's half the problem there as well... the tape will be
creating a gap between the speaker frame and the mounting points, which
only serves to exacerbate the "leakage" problem. If you have to use
something to physically isolate the speaker from the deck, use a "solid"
foam, and use it all the way around. I've used "RV foam" before, a
stick-on strip that seals up nicely (aka "weatherstripping tape"), when
such a tactic is required. See an example he http://tinyurl.com/4mddxs

Building a solid wood deck and just attaching the speakers directly to
that will be more effective, though.

I notice that Kenwood recommends using an angled adaptor with these
speakers, in a rear parcel shelf application:

http://india.kenwood.com/products/ca.../features.html


That's just to "aim" the mids and highs. Won't help this issue at all.
  #15   Report Post  
Posted to rec.audio.car
Matt Ion Matt Ion is offline
external usenet poster
 
Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:

The signal coming out of the deck is AC; the signal
phase has to be the same in both speakers. There is
no "right" or "wrong" polarity as such, they just
have to be the same. A DC meter won't give you a
meaningful reading.


The AC bit is news to me, I was under the impression
that the current to the speakers was DC, but as you
can probably tell I'm more or less ignorant in these
matters.


Not really... just a little n00bish. That's okay, it's always good to
learn something new!

If you feel inspired to understand it a little better, take a browse of
http://www.bcae1.com ("Basic Car Audio Electronics"), specifically
section 21 on "Audio Output".

Anyway, the meter showed a minus sign one way and not
the other, and I connected the two speakers
accordingly.


It's not unusual for an amplifier's output to have a slight DC offset,
which is probably what you were measuring, but there's no guarantee it
will be the same offset on both channels and thus not a valid indicator
of phase.

(Hmm, it's strange there's not actually a section on "phase" on BCAE...
it's a little crude, but there's a diagram and brief explanation at
http://www.classictruckshop.com/club...eo/systems.htm
- scroll down to "speaker phase")

That makes it a little easier then, because you can
check the polarity of the connections to the deck,
then confirm them at the speaker end. If you used
the factory speaker wiring, just follow the wiring
color codes and make sure the + and - outputs on the
deck properly match the terminals on the speakers.


My son actually had them written down (good boy!) and
they tallied with how we had the speakers wired so
it's all good as far as that goes.


Excellent!

The rear seats fold forward so there's nothing to
mount a sub on, and my son needs the folding seats to
stow golf clubs..


Ah. Of course, folding the seats down also introduces the acoustic
leakage problem we've been battling thus far, though hopefully not as
severely. He'll have to remember that he'll probably see reduced bass
output from the rear speakers with the seats down, and remember NOT to
try to compensate by cranking the bass control.

OK, so we make up an MDF parcel shelf and kill a
little of the bass, that's OK.
The system sounds fine apart from the bass distortion
so I'll tell him to go easy.


Turning down the bass control is the actual "fix" for the problem... the
rest of the exercise is intended to improve the speakers' own bass
response, so he doesn't NEED to turn up the knob.

Once again, thanks very much for your time and
patience.


No worries!



  #16   Report Post  
Posted to rec.audio.car
Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message

"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message
u

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.


You mean screw + tape, right?


Yes.


I can't see how they could vibrate against the
body.


Maybe the shelf itself, or a stiff covering...


The distortion is definately coming from the speaker
itself.


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


I get 6.25 inch nominal diameter.

They are a $50/pair class 3-way, which I would not
expect too much of.


$150 in Oz.


Not top of the range, but not rubbish, or so the
salesman assured my son.


I would say, towards the bottom of the market
segment.


Maybe.
It wouldn't be the first time a salesman has ripped
someone off.


or if there's any way of
reducing this distortion to acceptable levels.

Turn them down. ;-)


Looks like he will.


Rarely fails! ;-)

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.


I notice that Kenwood recommends using an angled
adaptor with these speakers, in a rear parcel shelf
application:

http://india.kenwood.com/products/ca.../features.html


I can easily make such a beast, but I doubt it will
reduce the distortion.


  #17   Report Post  
Posted to rec.audio.car
Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:

The signal coming out of the deck is AC; the
signal phase has to be the same in both speakers.
There is no "right" or "wrong" polarity as such,
they just have to be the same. A DC meter won't
give you a meaningful reading.


The AC bit is news to me, I was under the
impression that the current to the speakers was DC,
but as you can probably tell I'm more or less
ignorant in these matters.


Not really... just a little n00bish. That's okay,
it's always good to learn something new!


I try to do that at least once a day.
So far so good.


If you feel inspired to understand it a little
better, take a browse of http://www.bcae1.com
("Basic Car Audio Electronics"), specifically
section 21 on "Audio Output".


Will do.


Anyway, the meter showed a minus sign one way and
not the other, and I connected the two speakers
accordingly.


It's not unusual for an amplifier's output to have a
slight DC offset, which is probably what you were
measuring, but there's no guarantee it will be the
same offset on both channels and thus not a valid
indicator of phase.


Looks like we fluked it then.
1 in 4 chance I guess.


(Hmm, it's strange there's not actually a section on
"phase" on BCAE... it's a little crude, but there's
a diagram and brief explanation at
http://www.classictruckshop.com/club...eo/systems.htm -
scroll down to "speaker phase")

That makes it a little easier then, because you
can check the polarity of the connections to the
deck, then confirm them at the speaker end. If you
used the factory speaker wiring, just follow the
wiring color codes and make sure the + and -
outputs on the deck properly match the terminals
on the speakers.


My son actually had them written down (good boy!)
and they tallied with how we had the speakers wired
so it's all good as far as that goes.


Excellent!


He's a good lad.
A chemist by profession, so very thorough and
everything gets documented.


The rear seats fold forward so there's nothing to
mount a sub on, and my son needs the folding seats
to stow golf clubs..


Ah. Of course, folding the seats down also
introduces the acoustic leakage problem we've been
battling thus far, though hopefully not as severely.
He'll have to remember that he'll probably see
reduced bass output from the rear speakers with the
seats down, and remember NOT to try to compensate by
cranking the bass control.

OK, so we make up an MDF parcel shelf and kill a
little of the bass, that's OK.
The system sounds fine apart from the bass
distortion so I'll tell him to go easy.


Turning down the bass control is the actual "fix"
for the problem... the rest of the exercise is
intended to improve the speakers' own bass response,
so he doesn't NEED to turn up the knob.

Once again, thanks very much for your time and
patience.


No worries!


The internet is indeed a wonderful place, people
willing to help just because they can.
I'm a carpenter by trade, and a year or so ago needed
to cut some radius rafters for an old fashioned house.
The common rafters weren't a problem but the two hips
had me stumped so I left a message on a mathematics
newsgroup and had the answer within a day.
Emailed the guy some pictures of the finished article,
he was very happy to see a practical application for
his theoretical knowledge.
So thanks again, and if you need any advice on
building feel free to ask.
Neil.


  #18   Report Post  
Posted to rec.audio.car
Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Arny Krueger wrote:

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.


You mean screw + tape, right?


Ugh... there's half the problem there as well... the
tape will be creating a gap between the speaker
frame and the mounting points, which only serves to
exacerbate the "leakage" problem. If you have to
use something to physically isolate the speaker from
the deck, use a "solid" foam, and use it all the way
around. I've used "RV foam" before, a stick-on
strip that seals up nicely (aka "weatherstripping
tape"), when such a tactic is required. See an
example he http://tinyurl.com/4mddxs


I know the stuff, use it in my work from time to time,
but it sounds like I could dispense with the tape
altogether.


Building a solid wood deck and just attaching the
speakers directly to that will be more effective,
though.


That's for Sunday.
I've scored some 12mm particle board from a cabinet
maker mate.


I notice that Kenwood recommends using an angled
adaptor with these speakers, in a rear parcel shelf
application:

http://india.kenwood.com/products/ca.../features.html


That's just to "aim" the mids and highs. Won't help
this issue at all.



  #19   Report Post  
Posted to rec.audio.car
Arny Krueger Arny Krueger is offline
external usenet poster
 
Posts: 17,262
Default 6" Kenwood speakers


"Neil Green" wrote in message
u...

"Arny Krueger" wrote in message
...
"Neil Green" wrote in message

"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message
u

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.


You mean screw + tape, right?


Yes.


I can't see how they could vibrate against the body.


Maybe the shelf itself, or a stiff covering...


The distortion is definately coming from the speaker itself.


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


I get 6.25 inch nominal diameter.

They are a $50/pair class 3-way, which I would not expect too much of.


$150 in Oz.


Not top of the range, but not rubbish, or so the
salesman assured my son.


I would say, towards the bottom of the market segment.


Maybe.
It wouldn't be the first time a salesman has ripped someone off.


or if there's any way of
reducing this distortion to acceptable levels.

Turn them down. ;-)


Looks like he will.


Rarely fails! ;-)

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.


I notice that Kenwood recommends using an angled adaptor with these
speakers, in a rear parcel shelf application:

http://india.kenwood.com/products/ca.../features.html


I can easily make such a beast, but I doubt it will reduce the distortion.


It could provide additional stiffness and mass, as well as better
distribution of the highs.


  #20   Report Post  
Posted to rec.audio.car
Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Arny Krueger" wrote in message
. ..

"Neil Green" wrote in
message
u...

"Arny Krueger" wrote in message
...
"Neil Green" wrote in
message

"Arny Krueger" wrote in
message
...
"Neil Green" wrote
in
message
u

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.

You mean screw + tape, right?


Yes.


I can't see how they could vibrate against the
body.

Maybe the shelf itself, or a stiff covering...


The distortion is definately coming from the
speaker itself.


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

I get 6.25 inch nominal diameter.

They are a $50/pair class 3-way, which I would not
expect too much of.


$150 in Oz.


Not top of the range, but not rubbish, or so the
salesman assured my son.

I would say, towards the bottom of the market
segment.


Maybe.
It wouldn't be the first time a salesman has ripped
someone off.


or if there's any way of
reducing this distortion to acceptable levels.

Turn them down. ;-)

Looks like he will.

Rarely fails! ;-)

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.

I notice that Kenwood recommends using an angled
adaptor with these speakers, in a rear parcel
shelf application:

http://india.kenwood.com/products/ca.../features.html


I can easily make such a beast, but I doubt it will
reduce the distortion.


It could provide additional stiffness and mass, as
well as better distribution of the highs.


Maybe, and it'll give me something to do as well.
On Matt's advice I'm going to make an insert for the
parcel shelf, and a couple of angled enclosures won't
take long.
Thanks for the tips.




  #21   Report Post  
Posted to rec.audio.car
Matt Ion Matt Ion is offline
external usenet poster
 
Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:

I know the stuff, use it in my work from time to time,
but it sounds like I could dispense with the tape
altogether.


Yeah, unless you need to seal tight against an uneven surface, you
really don't need any kind of foam.

Building a solid wood deck and just attaching the
speakers directly to that will be more effective,
though.


That's for Sunday.
I've scored some 12mm particle board from a cabinet
maker mate.


That should do the trick, and it'll be a little more flexible than MDF,
which should make it a little easier to fit. It'll work alright for
this purpose, but just for future reference, particle board is NOT
recommended for speaker enclosures, especially sub boxes, because it's
not dense enough; MDF is usually the material of choice.
  #22   Report Post  
Posted to rec.audio.car
Matt Ion Matt Ion is offline
external usenet poster
 
Posts: 420
Default 6" Kenwood speakers

Neil Green wrote:

Maybe, and it'll give me something to do as well.
On Matt's advice I'm going to make an insert for the
parcel shelf, and a couple of angled enclosures won't
take long.
Thanks for the tips.


Well, we'll look forward to seeing some pictures of your creation.

Main thing to remember through this is that the purpose of it all is to
keep the front and back of the speaker cones separated as much as
possible, so make sure the angled pieces, if you make them, seal well
against the shelf, and that the speakers seal against them. Don't need
to use silicone or anything, just make sure they're smooth and the
speakers are snug.
  #23   Report Post  
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Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:

Maybe, and it'll give me something to do as well.
On Matt's advice I'm going to make an insert for
the parcel shelf, and a couple of angled enclosures
won't take long.
Thanks for the tips.


Well, we'll look forward to seeing some pictures of
your creation.

Main thing to remember through this is that the
purpose of it all is to keep the front and back of
the speaker cones separated as much as possible, so
make sure the angled pieces, if you make them, seal
well against the shelf, and that the speakers seal
against them. Don't need to use silicone or
anything, just make sure they're smooth and the
speakers are snug.


Yep.
If I make them I'll post the pics, along with an
appraisal of how it all works.


  #24   Report Post  
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Neil Green[_2_] Neil Green[_2_] is offline
external usenet poster
 
Posts: 12
Default 6" Kenwood speakers


"Matt Ion" wrote in message
...
Neil Green wrote:

Maybe, and it'll give me something to do as well.
On Matt's advice I'm going to make an insert for
the parcel shelf, and a couple of angled enclosures
won't take long.
Thanks for the tips.


Well, we'll look forward to seeing some pictures of
your creation.

Main thing to remember through this is that the
purpose of it all is to keep the front and back of
the speaker cones separated as much as possible, so
make sure the angled pieces, if you make them, seal
well against the shelf, and that the speakers seal
against them. Don't need to use silicone or
anything, just make sure they're smooth and the
speakers are snug.


Made the angled enclosures today, but couldn't cut the
shelf insert as the car was at the mechanics for most
of the day getting serviced and Boy Wonder went
straight from the garage to pick up his girlfriend.
Tomorrow's Mothers Day in this part of the world so
project "improve the bass in the Nissan" will have to
wait till next weekend.
Keep you posted Matt.
Cheers
Neil.


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