EM rear radio speaker placement picture

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mark60609
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EM rear radio speaker placement picture

Unread post by mark60609 » Thu Aug 03, 2017 6:18 pm

Hello Corvair fans, I am going to install a nos rear radio speaker in my '64 Monza Coupe. Does anyone have a picture of a factory correct placement for this?

mark
'64 Monza Coupe in restoration

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toytron
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Re: EM rear radio speaker placement picture

Unread post by toytron » Sat Aug 05, 2017 11:51 am

I am not positive but did it go in the center top of the back seat?

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bbodie52
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Re: EM rear radio speaker placement picture

Unread post by bbodie52 » Sun Aug 06, 2017 3:45 am

:welcome2: :wave: Welcome to the Corvair Forum!

:google: :search:

I found this image of a 1963 Chevrolet radio and speaker brochure. The Corvair rear seat speaker is shown in the lower-right portion of the brochure...

Image

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S & M Electro-Tech has developed a complete line of new replacement speakers engineered to fit in collector cars and function properly with OEM radios. Our speakers are manufactured in the USA using compact high energy neodymium (NEO) magnets that allow these speakers to fit where others won't. Neodymium magnets (commonly referred to as super magnets) are 1/10 the physical size of round ceramic magnets found on most modern speakers but provide the same or higher field strength. Most of our speakers are true 8 ohm impedance and are fully compatible with 10 ohm Delco speakers. Many have whizzer cones for improved high frequency response and fabric or sanoprene rubber surround and larger spiders for improved low frequency response. They work exceptionally well with original Delco, Ford and Mopar radios made from the 40's through the mid 70's and will make your classic radio sound better than new. Available in most popular sizes used with car radios from the late 1930’s through the mid 1970’s. Most of our speakers can handle the added power produced by our AM/FM conversion radios and modern car radios. Our speakers carry a 5 year warranty against manufacturing defects.

Compare our replica 4 x 10 speakers to original Delco slim line speakers used in many 1960's GM products. The original "Delco Special Rectangle" is on the top left, our replacement speaker is on the top right. The bottom left speaker is our 4 x 10 Oval replacement. The 2 middle 4 x 10 oval speakers are original Delco 4 x 10 oval speakers. The lower right 4 x 10 is a common 4 ohm replacement speaker sold by many auto parts supply stores and restoration parts suppliers. The magnet on our speaker has more the twice the field strength of the ceramic magnet shown on the lower right speaker and 4 times the strength of the original alnico magnets used on the original Delco speakers.


Original Delco 4x10 Special Rectangle.................................................Our 4x10 Replacement
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:link: http://www.turnswitch.com/speakers.htm
Bruce Webster wrote:Image
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The Corvair Stereo That Never Was

Posted: Aug Tue 19, 2014 2:03 am

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Thought a closer pic of my ready to install, early model Corvair stereo might be of interest. I cobbled this together out of familiar and not so familiar Chevy components. I hauled it out of the attic today just to see if it still works and refamiliarize myself with it. I had forgotten that the receivers volume and tone controls are bypassed when it is connected to the multiplex. It might have been better to keep the volume control as is and add separate bass and treble controls on the multiplex rather than just a single tone control. I suppose a lot of what we find common today in stereo was experimental in the mid '60's.

The only way of knowing that the radio was originally from a Chevy is the Chevy bowtie emblem on the AM dial ( not shown ). Still plays pretty good....especially when hooked up to a decent set of German speakers.
:link: http://antiqueradios.com/forums/viewtop ... 4&t=257633

:welcome:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

dave t
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Re: EM rear radio speaker placement picture

Unread post by dave t » Sun Aug 06, 2017 8:32 pm

All delco radios of that era are 10 ohms. Current speakers are 8 ohm. Some vintage radio shops have special 10 ohm speakers available. Be sure that whatever you get are 10 ohm. Your radio will love you, last longer and sound better.

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bbodie52
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Re: EM rear radio speaker placement picture

Unread post by bbodie52 » Sun Aug 06, 2017 11:45 pm

10 ohm car speakers
INFO GATHERED FROM THE INTERNET REGARDING 10 OHM SPEAKERS

Putting a resistor in series with an 8 ohm speaker makes the bias go crazy in those old Delco radios. Don't do it, or else you'll be buying a very expensive output transistor (not made anymore).

I wouldn't add resistors to a speaker to make the load what you want it to be .. on speakers its a reactive load not a resistive. as far as ohms go. . short story is if a speaker is a 4 ohm speaker , its only at 4 ohms that it is at its resonant frequency . So, in short, at other frequencies its at varying impedance. any where from 1 to 40 ohms. depends on frequency. The resistor will just soak up the power so to speak. Much of the output power is dissipated by the resistor rather than the speaker. It will work, but I wouldn't do it. Resistance isn't the same thing as impedance. You can't do this test properly with a ohm meter, you need a impedance tester...You will need to discuss this with a radio geek about watt output and other specifics.

Many "modern" vehicles in the GM lines have used 10 ohm speakers. The problem is, unless you know an exact part #, or a vehicle application, most counter guys just frown on you. Sometimes even with the info, they still don't want to track down the stuff.

All factory Delco radios, AM, AM FM, mono, stereo, 8 tracks, multiplex, reverbs from the 60's and 70's required 8 to 10 ohm speakers to work properly. It should be clearly die stamped on the units housings. "Do not operate without 8 to 10 ohm speaker" The radio service manuals indicate this also. If incorrect speakers are used they will play but play lower than the correct 8 or 10 ohms speakers and the sound will becomes fuzzy or lower and intermittent after 15 min. of play time. But most important the wrong speakers overload the outputs in the radio making them very hot. These will short out the radio over a short period of play time. Sometimes in a matter of a minute.

Replacing a 10 ohm speaker with a 4 ohm speaker can be bad news for your equipment. Sure, you will find a lot of blog info from people that have added resistors and wired in series, etc. and say it works. But, your new speakers have less than half the resistance of the originals so they will draw twice as much current. Doubling the current drawn through your radio means almost certain death.

If your factory speakers are shot, torn or don't play well, DO NOT THROW THEM WAY! Most speakers have a specific fit to your car and can not be replaced new! There are speaker restorers out there that do a respectable job.

On a final note: "can I just wire two 4 ohm speakers in series? " Not really. Again, that depends on the wattage of the radio. Series wiring is for speaker boxes in modern large amp rated systems. Again, You will need to discuss this with a radio geek about watt output and other specifics.
:link: https://sites.google.com/site/chevvyedd ... r-speakers

Resistance is a measurement based on a DC signal. Music is a complex AC signal made up on a range of frequencies combined together. Speaker IMPEDANCE is a resistance to an AC signal current flow. Speaker impedance changes based on the frequency of the signal fed into it. Since music has a lot of simultaneous frequencies, what you end up with is something called “nominal” impedance. That’s more or less the lowest amount the speaker will dip down to in resistance to the load applied at any given frequency within its operating range.

True 10 ohm speakers have a nominal rating that will restrict average maximum current flow from the source output amplifier transistor circuit, which helps to restrict the current and helps to protect the output transistors from overheating and possibly suffering damage as a result. An 8 ohm speaker could possibly permit slightly greater current flow at maximum volume levels, but music is not a continuous signal level at one frequency, but is constantly varying in level and frequency. And it is unlikely the user is going to turn the volume up to maximum to drive the output transistors that hard. Some speakers are more efficient, creating a greater Sound Pressure Level (SPL) for a given input signal strength than other speakers might. The magnet design and other efficiency factors come into play. So don't be too concerned if the only speakers you can find have a nominal impedance rating of 8 ohms instead of 10 ohms. Just play your radio at a reasonable level and enjoy driving your Corvair while listening to The Beach Boys, Rush Limbaugh, or ??? :guitar:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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