Where would we be without the car stereo? In a country with as much land mass as the U.S., it's almost impossible to imagine long drives without music or talk radio—and, more recently, audiobooks and podcasts—to keep us company. During the Roaring Twenties, driving was largely a silent affair, aside from the noise of the engine and the sound of thin tires rolling over mostly unpaved roads. But beginning in the 1930s, with mass adoption a generation later, the car radio eventually became part of the American drive for almost everyone.

Today's cars come with audio systems that are nothing like those early radios, from 10+ speaker systems and powerful amplifiers, to extra channels, subwoofers, and finely tuned frequency response curves that match specific car interiors. It has certainly been quite a leap—so how did we get here? Come with us, as we take a look back at how the car stereo became what it is today.

The First Car Radios

Monophonic AM radio was the norm for a long time, beginning with the first in-car audio system more than 80 years ago. In 1930, Paul and Joseph Galvin, along with William Lear, developed the first automobile dashboard radio and named it the "Motorola," or motorized Victrola—and demonstrated the 5T71 prototype (pictured, below right) in a Studebaker. Motorola went on to sell millions of car radios, and later, two-way radios for police and fire departments, home stereo systems, and televisions before moving into transistors, solid-state electronics, and semiconductors.

The image of a couple on the open road in a convertible in the 1950s, complemented by the sound of AM radio and the beginnings of rock and roll, became indelibly imprinted in the American psyche. Several advances contributed to this. Blaupunkt debuted the first automotive FM radio in 1952, though AM ruled for the rest of the decade and into the 1960s. In 1953, Becker unveiled the first "Seek" station-search, which let drivers sample each available radio station for a few seconds before choosing one to listen to for longer. And newer transistor-based radios in the mid-to-late 1960s reduced the amount of space and power required—no more vacuum tubes.

Stereo 8, Compact Cassettes, and Compact Discs

It's tough to fathom, but it wasn't until the 1960s that drivers and passengers could actually control which songs they listened to. That is, with one almost-forgotten exception: A bizarre Chrysler in-dash turntable that played 7-inch, 45rpm singles in 1956. (That went nowhere fast.)

Stereo 8, or eight-track tapes, are now typically known for horrid sound quality and cheesy plastic construction. But for a while they were the only practical way to customize a playlist. Compact cassettes were always a better option, even right from the start, when Philips unveiled the format in 1964, and the first stereo radios followed soon after. But lower-priced, clunky eight-tracks stuck around for most of the 1970s anyway.

The early 1970s also brought us the real beginnings of what we now call the aftermarket, with custom stereo outfits like Crutchfield popping up to cater to those who wanted to improve their vehicles' audio capabilities beyond what any car manufacturer or dealer offered. Vendors like Alpine, Blaupunkt, Kenwood, and Pioneer began to do well selling cassette receivers and better-quality speakers. The early 1980s also brought us the first "Benzi box"-style pull-out stereo receivers, which were a response to the plague of break-ins and theft that afflicted many cities in the U.S. around that time. Later, receivers with detachable and even motorized faceplates made it much easier to protect your investment.

By this point, enthusiasts and car manufacturers also began to pay more attention to the sound quality of the amplifier (pictured, left) and speakers themselves. For decades, car audio speakers were single, full-range drivers—often you'd get only one, in the center of the dashboard. Think of the old Delco full-range speakers found in many GM vehicles in the 1960s. Later, we began to see the first 2-way and 3-way models that integrated separate tweeters and midranges in a plastic or metal bracket ahead of the main woofer, which was then relegated to bass duties. Miniature, passive 2-way and 3-way crossovers—first seen on home stereo systems—split the incoming audio signal into separate frequency ranges, each of which was directed to the appropriately designed speaker driver.

CDs, Subwoofers, and Components

Beginning in the early 1980s, car stereos began to rival home stereos in their sophistication and sound quality. The first car audio competitions began around this time as well. Multiple speaker configurations began to take hold in earnest. It was common to find upgraded or custom systems with two or three separate (or "component") drivers per side in the front (pictured, below) plus rear deck speakers as "fill" to pull the image back and fill out the sound, and one or more subwoofers (pictured, below right) either in their own separate enclosures or mounted in the rear deck. In the 1990s, we began to see higher-end systems incorporate a genuine center channel to improve imaging; Chrysler included this in some of their upscale Infinity stock systems as well.

The move from tape-based systems to the compact disc was particularly significant. The CD brought improved sound quality that remained pristine for thousands of plays, instead of degrading over time—until scratches rendered it unreadable, of course. CDs also let you skip tracks back and forth instantaneously, instead of tedious fast forwarding and rewinding. Multiple-disc CD changers began to appear in the late 1980s, and let you store as many as five, six, or even 10 CDs at a time, and switch between them while you were driving. By the mid-1990s, it was common to find a CD changer in a given car's trunk or underneath the front passenger seat.

In fact, CDs were a step forward in all respects save one—customizability. For most of the 1980s and 1990s, CDs were fixed albums, like vinyl records; although CD burners were introduced early on, affordable consumer products didn't take hold until around the turn of the millennium. For a while, many cars offered CD player and cassette deck options, and sometimes both in a single, large receiver: one for ultimate sound quality and instant gratification after a trip to Tower Records, and one for custom cassettes and any old prerecorded tapes you still had lying around.

One other note on aftermarket car stereos is worth mentioning here: Simply put, automakers began to make it tougher to install them. For many years, single-DIN, double-DIN, and a few other receiver sizes were standard, so you could easily swap in an aftermarket receiver, especially using the appropriate install kit from Crutchfield or another retailer. The same went for speakers in the front doors, rear doors, rear deck, and so on. But as automakers began to incorporate anti-theft systems, as well as custom upgraded audio systems, they also began to blend them into the dashboard using a variety of non-standard sizes and openings. Whether this was purely for profit, for interior style reasons, or just to discourage buyers from tampering with the vehicles, it has frustrated a lot of audio hobbyists over the years.

The Digital Music Revolution

It's tough to overstate how revolutionary the digital MP3 player was. Virtually the moment the iPod and competing models took off in popularity, sales and usage of the CD began to decline, and what remained of the compact cassette market disappeared almost overnight. By now, most of us are familiar with MP3 palyers, which store thousands of songs, make it easy to create custom playlists, and let you search by song title, artist, or album easily. But when it comes to cars, there's plenty of tension in this market. Even as people began to buy iPods and other players by the millions, it wasn't always simple to connect them to car stereos—and in some cases, it's still complicated today.

For example, by the mid-2000s, cars began to come with auxiliary inputs that connected to any MP3 player's headphone jack. But true iPod integration remained elusive for longer; after some early BMW and MINI systems, we're only now beginning to see more and more cars come with USB jacks that can read standard iPod and iPhone playlists, albums, artists, and songs, or even hook into iPhone apps (pictured, above). Even so, that leaves out the millions of people with Android phones, BlackBerrys, and other handsets. For now, stereo Bluetooth streaming, or sideloading music via USB flash drives or SD cards remain the best option in those cases.

The biggest problem for music in cars today has nothing to do with sound quality—well, aside from MP3 and AAC files, which are fine most of the time but don't match the experience you'd get from a proper CD or uncompressed audio file. Instead, the problem is access. In an increasingly fragmented world of tech, it's not always clear what sources will work in a given vehicle, at least without doing some research first. Buy a new car off the showroom lot in 2012, and you're virtually guaranteed at least an auxiliary jack for your mobile device, if not more. But more advanced integration varies by the vehicle and by the device, and it can sometimes get quite complex. Ask anyone who came away frustrated with BMW's iDrive or one of the earlier Ford Sync systems.

It almost makes you long for the days of the AM radio and two big dials for volume and station tuning. Almost.

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