Out of phase headrest speakers

Archives of Posts to the NZ MX5 List back in 2003
Locked
Mike Pearson - WYSIWYG...

Out of phase headrest speakers

Post by Mike Pearson - WYSIWYG... » Sun Jan 19, 2003 10:24 pm

Hi, I had that common problem reported with the factory headrest speakers,
being that they were connected out of phase.

Now that I have fixed the wiring, the volume is better, and with the Fader
set to rear speakers only, I can adjust balance from Left to Right, and hear
the sound move from the Left to Right speakers in a seat.

1. Can someone confirm for me how you check polarity using the AA battery
(see below).
2. Can Grant / Tim and anyone else who's noted their correct wiring, send me
their diagrams as per below. There seemed to be some difference between the
different years/models.


HOW I DID IT


CAR / HEADREST CONNECTOR

This is located under the front of each seat (get a torch). By moving the
seat right back, there is sufficient slack to pull the connector out and
operate on it. I had to strip away a foam cover, holding the CAR / HEADREST
parts of the connector together.

|\ -Tab
RED/BLU +-|-\--+--------+ WHT/BLU
YEL/BLU | | | BLK/BLU
| CAR | H/REST |
RED/YEL | | | YEL/BLU
WHI/BLU +------+--------+ RED/BLU

Each end of the connector has 4 wires going into it. The CAR connector has
a push-in TAB. The following wiring diagrams are described with the TAB
surface FACING AWAY from you, (ie, NOT up, NOT down, NOT facing you).

I found it easier to reposition the plugs on the CAR end. You insert a
small flat blade screwdriver (2mm blade), into the connector end, and lever
up / push back the little tin socket. They come out easily, no force is
required. There is a positive click when you insert them back in. Take
note of the orientation of the socket, in relation to the tab, so you can
put it back the right way. Once I figured out how to do it, it took me less
than a minute to remove and reposition 4 wires.


1990 Eunos Roadster - NA6CE-122890
* = change pins
+----------------+---------+----------+
| FACTORY CONFIG | CAR | HEADREST |
+----------------+---------+----------+
| Top | * | RH + |
| Close to tab | RED/BLU | WHT/BLU |
+----------------+---------+----------+
| Bottom | * | RH - |
| Away from tab | WHI/BLU | BLK/BLU |
+----------------+---------+----------+
| Top | | LH + |
| Away from tab | RED/YEL | YEL/BLU |
+----------------+---------+----------+
| Bottom | * | LH - |
| Close to tab | YEL/BLU | RED/BLU |
+----------------+---------+----------+

+----------------+---------+----------+
| REWIRED CONFIG | CAR | HEADREST |
+----------------+---------+----------+
| Top | | RH + |
| Close to tab | WHI/BLU | WHT/BLU |
+----------------+---------+----------+
| Bottom | | RH - |
| Away from tab | YEL/BLU | BLK/BLU |
+----------------+---------+----------+
| Top | | LH + |
| Away from tab | RED/YEL | YEL/BLU |
+----------------+---------+----------+
| Bottom | | LH - |
| Close to tab | RED/BLU | RED/BLU |
+----------------+---------+----------+


PHASE POLARITY
To test phase polarity I used a test described on miata.net. It was not
clear to me whether you put (+ to +) and (- to -) or not, this is what I
have assumed.

To test phase polarity, you need an AA 1.5 volt battery and two pieces of
speaker wire, stripped at each end. You need to do the test on both the LH
and RH speakers. Open up the seat speaker (4 screws). Attach a small wire
to each speaker connector, noting which is + and -. Touch the + wire to the
+ terminal on the battery. Touch the - wire to the - terminal on the
battery. If the speaker moves inward, the polarities are backward. If it
moves outward then you have it right.


OTHER CONFIGURATIONS TRIED:

+----------------+---------+----------+
| FAILED CONFIG | CAR | HEADREST |
+----------------+---------+----------+
| Top | | RH + |
| Close to tab | WHI/BLU | WHT/BLU |
+----------------+---------+----------+
| Bottom | | RH - |
| Away from tab | RED/YEL | BLK/BLU |
+----------------+---------+----------+
| Top | | LH + |
| Away from tab | YEL/BLU | YEL/BLU |
+----------------+---------+----------+
| Bottom | | LH - |
| Close to tab | RED/BLU | RED/BLU |
+----------------+---------+----------+
- Balance did not work


+----------------+---------+----------+
| FAILED CONFIG | CAR | HEADREST |
+----------------+---------+----------+
| Top | | RH + |
| Close to tab | RED/BLU | WHT/BLU |
+----------------+---------+----------+
| Bottom | | RH - |
| Away from tab | RED/YEL | BLK/BLU |
+----------------+---------+----------+
| Top | | LH + |
| Away from tab | YEL/BLU | YEL/BLU |
+----------------+---------+----------+
| Bottom | | LH - |
| Close to tab | BLU/WHI | RED/BLU |
+----------------+---------+----------+
- Lower volume

Grant
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 175
Joined: Thu May 18, 2006 9:41 pm
Location: Sunny Blenheim

Out of phase headrest speakers

Post by Grant » Sun Jan 19, 2003 11:25 pm

I'm not sure if I still have the info on the wiring. My drivers seat was
different to the passenger seat as well, just to add to the confusion. To
check the phasing of all speakers using a 1.5volt (AA) battery, you need to
be able to see all the speaker cones. Connect the battery in turn ro each of
the speaker connections at the radio end of the cables (disconnected from
the radio). It doesn't matter which way round you connect the battery, as
long as it is the same for all four speakers (ie left front and rear, right
front and rear). When you momentarily connect the battery to a speaker, its
cone will move in or out, depending on the polarity. Using the same polarity
for each speaker, check that the cones all move in the same direction. If
they do, the phasing is correct. If not, reverse the wiring to that speaker
only.
For a dramatic improvement in the headrest speaker sound quality, replace
the factory speakers with somw four inch units. The Warehouse ones (at
$30.00 a pair) will fit without having to carve foam from the inside of the
headrest. Just push them in to the foam and zip up the covers. The frequency
respons is much better than the originals with much better treble clarity
and greater bass response. You can run them loud enough to be able to feel
the vibration in the seat and they are still quite clean.
I have just fitted a JVC stereo with MP3 playback. Great to have more than
10 hours of music on only one CD! Also cheaper than a 10 disk stacker and
doesn't use up any extra space.

Grant.
Red 2006 NC Tiptronic
FIX A PC

Graeme Naisbitt

Out of phase headrest speakers

Post by Graeme Naisbitt » Mon Jan 20, 2003 8:37 pm

Or you could fit some high quality speakers at only $150 a pair =) and a
laptop in the boot with a 10gig harddrive >:o)

Graeme (my middle name is D4NGER)

Aaron Hart

Out of phase headrest speakers

Post by Aaron Hart » Tue Jan 21, 2003 7:49 am

As funny as that sounds I quite often plug my IPAQ into my stero useing the lighter port to keep the IPAQ charged and it works a treat... Hmm does this make me a computer car g33k ?

Aaron

Graeme Naisbitt

Out of phase headrest speakers

Post by Graeme Naisbitt » Wed Jan 22, 2003 7:02 am

Lol, nah you'd only be a g33k if it was fitted into your dashboard
permanently, running Linux and enabled you to hook into other peoples
wireless networks...

Graeme
D4NGER

Locked

Return to “2003”

Who is online

Users browsing this forum: No registered users and 11 guests