RetroSound Car Audio: Build A Radio To Fit Your Classic Dash Opening

retrosoundleadartClassic automobiles up through the 1970s had an AM/FM radio with two knobs and a dial indicator. While that was standard on many vehicles in that era, those two round holes in the dash – separated by the long, rectangular hole – have been a source of consternation with many classic vehicle owners when it comes to audio upgrades.


There were no standards in 1965, so cutting this dash was one of the alternatives.

Today’s modern stereos meet what is called DIN, which stands for Deutsches Institut für Normung, originally established by the German standards body. The International Organization for Standardization (ISO) created ISO 7736, which creates a standard size for car audio head units, and that’s what you’ll find at car stereo and electronics stores all over the U.S.

In the early years of car audio, however, there were no standards, and when you want to fit a radio into the dashboard of a classic car, you will quickly find out that one size doesn’t fit all. You have two choices, however, and while the first is to cut your dash and radio faceplate to accept modern DIN radios, the second was our choice: RetroSound Manufacturing.


RetroSound can provide you with a complete audio system solution, with front or rear speakers, a center channel speaker, a powered subwoofer, and the coolest part: the build-it-yourself radio.

RestroSound helps preserve the dash on classic cars by providing a radio that not only fits into those three holes in the dash, but the radio fits the application perfectly. Instead of the “you get what you get” method of trying to fit a square peg into a round hole, the RetroSound car stereos are adaptable to fit a variety of applications correctly. We got our hands on a Redondo head unit and all of the attachments from RetroSound so we could build a radio to fit our existing dash – without cutting or modifying the faceplate.


Who needs disc changers or cassettes when you have USB and iPhone inputs? Not us!

Old School Radios And Modern Music Formats

Let’s get back to that dreaded old school radio faceplate and dash. Now that modern audio systems have USB and iPhone plugs, as well as Bluetooth connectivity, we are able to listen to MP3s and never have to worry about things like CDs, cassette tapes – or the dreaded eight-track. It’s easy to download some of your favorite songs directly from your computer or iPhone to a USB thumb drive for hours upon hours of music.


The base unit for the Redondo, it’s compact – and we built our radio on this unit.

But listening to your favorite songs on an original car radio is limited to whatever radio station is selected, or possibly a cassette player depending on the year. RetroSound radios have all the modern media inputs so that you can install a retro-look stereo into a classic dash, without sacrificing your favorite songs by way of whatever the DJ decides to play.

Included with our Redondo is an iPhone/iPad connection and two USB drive inputs, meaning our music selection is whatever we download to an iPhone or a thumb drive. The output for the Redondo includes an internally amplified high-level output for direct-to-speaker connections, and low-level RCA-type outputs for connection to an audio amplifier.

The Redondo not only has inputs for USB and iPhone/iPod, but it is Bluetooth capable, and includes the microphone for hands-free conversations.

The advantage of the RCA output is that the low-level signal has minimal distortion, which makes it perfect for amplification. The high-level is already amplified and would not require use of an external amplifier. If you choose an external amplifier, it’s highly recommended to use the low-level RCA outs, which consists of front, rear, and a subwoofer output.


It’s almost like buying a Lego kit: you get all the parts you need, some you can use, and some you won’t. You even get to choose your own knob style from the website when you order your radio.

Build Your Own Radio

If you’re the kind of person who loves to build things, then RetroSound’s radios are just the ticket. How many people can say they built their own car radio? While you won’t have to build the electronics portion of the radio, you do get to assemble the radio to fit your existing dash.


Choose your own knob set to match or complement your dashboard.

One of the bonus features of this kit that we really liked was that we could choose our own knob set from the RetroSound website. Whether you’re trying to match your classic dash with knurled, chrome knobs, or you want smooth, black knobs, there are a dozens of knobs sets to choose from.

By test fitting the unit to the dash, we were able to place the two control knobs exactly where they needed to be, as well as placing the five preset buttons and the display in the proper location to fit our radio faceplate.

Each of these can be adjusted to fit your dash, and that means no cutting whatsoever of your metal or plastic dashboard and trim. The faceplate on our radio had a thin strip that separated the display from the push buttons, and once we selected the proper bezel we were set up with a radio that was a perfect fit.

Building the radio to fit our dash was the fun part. You do have to pay attention to details - and those dreaded instructions.

Each of the components is electronic; once the positioning is determined, a cable plugs into the main unit to provide the power or display. Two sets of knob brackets allowed us to choose the proper depth of the tuning shaft sections, and we were able to use the included spacers to adjust that depth properly. A couple of tries later, we had the radio ready to be installed without any fitment issues.

Top: An overlay adds to the appeal of the RetroSound radio, making it appear as an old AM radio.
Bottom: After installing the radio, we were ready to install the speakers, a power antenna, and a powered subwoofer.

Antennas, Speakers, Amplifiers, Pods, Subwoofers

With RetroSound, you can fit that square peg into a round hole and it doesn’t stop there. With several speaker sizes from 4×6 to 6×9, and with under-seat amplified subwoofers you can be sure that your total sound package can come from the same place. RetroSound’s James Tate said, “Our systems are matched to the speakers, so you should be able to enjoy listening to your favorite music with or without an external amplifier.”

We also added a power antenna to our classic car, it’s a nice touch and make it a little easier to wash the car without having the OE antenna getting in the way – especially at the car wash. There are two styles, one with an extended cable-drive for difficult mounting, and a standard unit for direct mounting to the vehicle.


The powered subwoofer is compact enough to fit under a seat – and it’s adjustable to fine-tune the bass.

Next, we’ll work on setting up our Bluetooth for hands-free talking when a call comes in over the radio. But for now, we’re just going to enjoy some of our classic songs with just the right amount of bass from the powered subwoofer. With our new system, nobody will know that we’ve got more than just a stock AM radio mounted in our dash.

For us, it’s finally nice to have music in our classic car after being without it for the last 15 years. We just couldn’t bring ourselves to cutting apart our dash and trim pieces, and with RestroSound’s new Redondo we were able to keep our classic dash intact. You can see more of what’s available for you classic at the RetroSound Manufacturing website, and start listening to what you want to hear instead of what happens to be playing.


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About the author

Michael Harding

Michael is a Power Automedia contributor and automotive enthusiast who doesn’t discriminate. Although Mopar is in his blood, he loves any car that looks great and drives even faster.
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