Styrofoam planar speakers from Radio Shack circa 1973

[TWRackers]

I have a pair of rectangular planar speakers which were sold by Radio Shack back when I was in college, around 1973 +/- a couple of years. They're still fully functional, but I've never built proper enclosures for them, only a simple wood frame around the edges just to keep them from getting crushed or cracked. How would I go about finding someone who has the know-how and equipment to design and build simple but true enclosures for them? Enough years have passed that I don't have the specs on the speakers, other than their dimensions, their impedance (8 ohms each), and their approximate frequency range (quoted as 20-20,000 Hz on the data sheet, probably +/- 3 dB). They were purchased way back then with the intent to incorporate them into a low-cost electronic synthesizer project I was attempting, which is why I sought out speakers with as wide and flat a frequency response as possible.

For the record, Radio Shack also marketed at about the same time circular styrofoam speakers, roughly 8 to 9 inches in diameter and spec'd at 30-20,000 Hz. Does anyone remember either of these?

 

[geraldfryjr]

I remember those things!!!
They sound great!!!
But, I don't remember them being marketed by Radio Shack.

You can however find the speakers parameters using your computer and a very simple interface.

Here is one such program called Simple S,

http://www.acustika.org/?Home

and here is the interface that I have used with it,

http://wb6dhw.com/RLC_Meter/A Low Cost Automastic Impedance Bridge.pdf

http://wb6dhw.com/RLC_Meter.html

There are a few threads here at DIYAudio that is all about these types of programs.

REWv5 is another very good program that can be used with this interface to find the impedance curve and as well as frequency response of the driver if you have some sort of decent microphone that works good.

Here are some instructions on how to do this manually as well,

http://www.mh-audio.nl/downloads/read-measuring-tsp.pdf

http://www.webervst.com/spkrcalc/para.htm

Cheers !!!

jer 🙂

 

[geraldfryjr]

There are other links as well but I have used the above methods and software with great results by using the added weight method.

Just make sure that when you add your calibrated weight that it is securely attached the to Diaphragm without them vibrating or else the measurement won't be valid.

I use a stack of coins as they are exactly a certain amount of mass each as per year period made, and that can be found here,

http://en.wikipedia.org/wiki/Penny_(United_States_coin)

It doesn't matter how much mass you add as long as you know what it is when you enter it into the calculator or program.

Hope this helps you!!

jer 🙂