<VV> Installing Radio in Corvair

Dave Thompson dave.thompson at verizon.net
Wed Apr 23 14:41:08 EDT 2008


Steve,

Here's a semi-simplified answer to your questions:

Check out the documentation of your radio. See what the output impedance is,
also written as speaker impedance. Typically it is 8 ohm (ohm is usually
shown as the old Greek omega upside down U symbol). Assuming you have 8 ohm
speakers, if you connect the positive wire to both positive speaker
terminals and the negative to both negative terminals you will give the
radio a 4 ohm load. Most modern radios can take that just fine. If you do
not have rear speakers, just tape off the rear speaker wires and adjust the
front to rear fader control to full front and leave it.

As for the EM vent to speaker adaptor plates available, I looked at them
too. However, speakers work better if they have some sort of box behind
them. I won't get into the technical aspects of it but a box speaker will
sound substantially better than a raw speaker sitting on a table. The $40.00
plus price for the brackets will not give you the speaker performance you
are looking for. The 5-1/4 inch speakers you will mount in the brackets
still need some sort of box behind them for the bass to resonate in. I have
been looking (designing in my head) for a solution myself. At this point, I
have decided to spend that $40 plus to purchase a set of small box speakers
to be mounted up under the dash outside corners. I have other car priorities
right now so I haven't really looked for a good set yet. Perhaps a box could
be built for the vent to speaker brackets. I'm not saying you can't. I'm
just saying that a purpose built box speaker will take less R&D and building
time.

As for the dash speaker, I'm assuming you got the plate with two speakers to
replace the stock single speaker. That's what I have in my '63. Lately, I
purchased two 4 inch foam speaker baffles at a local car stereo shop. You
can find them at Crutchfield.com (Item #237XT40). I removed the speaker
adaptor plate, I installed them, with a little trimming on the speaker
adapter plate and re-installed it into the car. They made a substantial
difference. Try the baffles before you add extra front speakers. Perhaps the
5-1/4 inch baffles would work on the vent to speaker adaptors too, I didn't
try it.

I hope this helped you out.

Dave Thompson

Steve wrote:
Having read the very knowledgeable postings on the proper way to wire stereo
speakers, I have a follow-up question.  On my EM I have replaced the
original dash speaker with an aftermarket two channel (stereo) speaker.  It
works fine, but is a little "weak" compared to the two 6x9s I am running in
the back.  I am considering bolstering the front end sound by adding two
additional speakers using the kick panel vent mounts offered by CU.  If I
were to do so, can I just run extension wires off of the dash speaker to the
new side speakers?  (Or is it preferable to "T" the front channel lines, so
that each line splits and then goes to the respective speakers?)  My stereo
has 50w per channel, so I think the power is available, but some of the
postings I read got me wondering if running two speakers off of each front
channel line would do any damage.


Thanks,

Steve Brennan

1962 Spyder Coupe

 






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