The other day I wanted to digitize a vinyl record for use on our little radio station, but circumstances were against me.
The other day I wanted to digitize a vinyl record for use on our little radio station, but circumstances were against me.
As it happens, we have three computer work stations, two of which are based on the legendary Amiga operating system, and the newest one is a Windows PC. The Amigas provided a video work station and an audio workstation, since we were in the business for many years. The Windows PC was added to provide online streaming.
Now 20-years old, the Amiga audio setup decided to die. The vinyl turntable was roadblocked two rooms away from the Windows machine, but I have four Scosche FM transmitters sitting around doing nothing, so I tapped one onto the turntable preamp and went to work digitizing all day at 88.5 FM.
Part 15 saved the day.
Thats really cool
And a creative way to digitize old vinyl records.
Did you use processing or leave that out? I would probably have left out processing as your tx most likely has one.
Vinyls Have Processing Built In
Good question about processing. I remember learning that vinyl records are pre-processed so they do not over modulate the groove and so that low levels are up above the groove noise, so I just set the pre-amp level so that the Scosche was within modulation limits. It worked so well that any future listeners will never know the difference.
RE: Vinyls Have Processing Built In
Well, yes and no … All records, vinyl or CD, have processing built in. This is done during the mastering process. Mastering audio for distribution almost enters the realm of the Magi. Mastering houses get the big bucks for what they do, which essentially involves tearing a studio recording apart and rebuilding it piece by piece, tweaking each little quirk with varying amount of compression, expansion, gating, EQ, and limiting. Those guys have “golden ears”, years of experience.
What you may be speaking of is the RIAA curve. Essentially what it does is decrease Low Frequency sound levels, increasing it as the frequency increases (but it’s an expansion curve not a straight line). That’s what minimizes the groove spread when the print master is cut. This is why some stereo systems have separate turntable inputs which are not the same as line or tape inputs, because the circuitry in the preamp reverses the processing.
If you have a USB turntable, the included software does it automatically, you don’t have to compensate. But if you digitize from an older standard turntable with its own RCA cables, you may need to run it through an RIAA processor, either an external device or software.
Worn vinyl disks can have pops, clicks, and hisses too. I recommend Bias Sound Soap software for cleaning up the signal.
Also, vinyl disks sound a bit different between tracks at the outer portion of the disk than they do towards the center. The needle is traveling in the grooves at a much higher speed towards the edge than towards the center. Thus there must be a compromise, i.e. tracks at the outside have better frequency response than towards the center, because the fluctuations in the groove cut are more stretched out and therefore have higher resolution. Same idea as a tape recording at 15 ips has better frequency response than one at 7.5 ips.
I digitize tapes and vinyl disks on almost a daily basis, and they virtually always need some sort of tweaking. I offer 3 pricing grades of digitizing: 1) Straight across, take what you get, fine for minimally played well-cared-for disks, 2) Clean up to acceptable levels, and 3) Audiophile archive quality, which may in fact not be possible strictly from badly worn records.
I agree, most people couldn’t tell the difference at the second level … but I usually can.
All True
Hi Ken Norris:
Good summary of the really very complex world of recording to and from disk. All I meant was the built in limiting/compression on a vinyl record which restricts the maximum and minimum audio levels. The equipment for this is analog, a pro RIAA preamp straight into the Scosche, with the 600-ohm lines terminated and un-balanced.
Once a record is recorded from FM radio into digital form I do small tweaks, like “normalizing” the level, in rare cases adding a little mid-range presence, and summing for mono. My only use is 24kbps mono streaming so it’s not as critical as re-mastering onto CD.
Another very esoteric question is that of “absolute phase,” in which some very critical listeners believe it matters which way the phase is directed, even in a monaural recording, and of course editing software has a handy feature called “invert” which allows trying it either way. Trouble is sometimes the phase gets inverted anyway as it travels through everybody’s system, including the listeners out in the world.
Somewhere I have a printed circuit used by ABC-Network to watch absolute phase on an oscilloscope, at least they did so back in the 1970s.
Part 15 Saved my life..
I used to be messed up on drugs and alcohol, now I’m messed up on Part 15 AM. 🙂
Part 15 Transmitters for audio links within a building
I operate MICRO1700, but I am also an AM
broadcast band DXer. Although I have heard
California and Europe from my Connecticut
location, my latest interest has been in
what are called the “Graveyard Channels.”
1230, 1240, 1340, 1400, 1450, and 1490 KHz.
These six channels on the AM band are the
most crowded, with most stations running
1000 watts, day and night. Each of these
channels has several hundred stations
running at the same time. Usually at
night they sound like a big mess, but
occasionally a station will float up out
of the clutter and ID. In my listening
shack, I have a Sony ICF-2010, and
a cassette deck connected to a multi
event timer. This can be set up to record
station IDs at the top and bottom of the
hour, or any way you want.
Also in the shack is a C Crane FM
transmitter that is connected to
the tape deck audio out jacks.
Anywhere in my house
I can listen to what is being taped on
a Sangean DT-400W pocket receiver
with ear buds,
(if the tape is running at that time.)
Anything I hear then is already recorded
on the tape.
If I am awake in the middle of the night I
can be very quiet and not disturb anyone.
Trips to the listening shack are not necessary.
This system can be improved. I am limited
to just hearing one frequency at a time, but
I don’t mind that. I do plan (soon) to use a computer
to record what is coming from the radio. Then
it can be recording all night long.
The C Crane FM transmitter and the Sangean
DT-400W make the remote listening possible.
Best Wishes
Bruce, MICRO1690/1700