We're cranking on a series about vinyl records, turntables and how all of that works. Last week's rundown of the tonearm got us moving toward understanding how this delicate marvel of engineering reproduces music, and we've got no shortage of tiny things to inspect along the way.
The technical design within turntables is worthy of appreciation, and nothing there fits the tiny designation better than the actual electronic music signal that comes out of a record player. If you were to throw a record on a standard player and connect the player directly to the "aux" input of your receiver or amplifier, what you'd hear would make you sad.
First of all, if you can hear anything, the volume is insanely low, even at full tilt on the volume knob of your amp. And second ... where'd the bass go?!
Every element of a record player is balanced with other elements. The tiny troughs and peaks deep inside the grooves of a record are the exact size they need to be to reproduce all sound. Too big and you'd need a bigger needle, which would need bigger suspension and would be less sensitive to treble. Too small, and you'd need a smaller, more sensitive setup at the needle, which would render it less durable and prone to breakage on big booms and bass and swelling dynamics.
Too shallow, and you lose those high frequencies to dirt, not to mention you risk popping the needle out of the groove on loud sections. Too deep and you start to incur damage to the record and the needle every time it's played.
There are a host of things like that on a record player, perfectly balanced to handle a pretty complicated job very well. But they still need some help to play back the full sound spectrum. In that vein, something big is done to the music prior to recording on vinyl in order to help out with a few of these challenges.
The main treatment to music before it's put to vinyl allows the needle to work a little less hard when it comes to reading and playing back bass. You might imagine that the bumps and troughs in the groove that represent bass are quite a bit bigger than the treble ones. If both were represented at the same loudness in terms of bump and trough depth, the needle would jump out of the record on every bass line and with every drum hit.
So before music hits a record, the bass is literally taken right out of it. A standard bass cut that was set in the middle of last century is called the RIAA curve. Every engineer doing this follows the same curve, so when you connect the turntable to your amp, but you place a phono-specific "preamplifier" in between them, the bass is restored to the exact level it should be.
And the volume? It's once again normal since these preamplifiers do what their name suggests — they bring the music signal up to a normal level before it hits the amplifier. Hard-working boxes, they.
A good turntable will usually not include a phono preamplifier. So if you're shopping for a deck, don't forget you need your bass and your volume, too.