Corey Bailey
Audio Engineering
USEFUL INFORMATION
TIME CHARTS
The charts on this page are provided to give you an idea of running times for
various reel-to-reel audio tapes and records. Starting with analog audio tape, the
chart below is from the box of an old reel of Irish (brand) tape and is calculated for
7” reels. The lengths shown on the left of the chart represent the different
thicknesses of audio tape.
The Single Track listing is for recording in one direction. This column can be used
for full track mono or any format for stereo recording, recorded in one direction.
The Dual Track listing is for recording in both directions. 1/2 track mono was the
available consumer format when this tape was produced. The same “Dual Track”
column can be used to calculate 1/4 track stereo recorded in both directions.
This tape is from the 1950’s. Notice the price stamped just below the brand logo.
It’s barley readable, but it is $2.88. Pretty pricey for 1958.
The tape in this particular box is 1.5 mil acetate, and it played just fine.
There is a picture of the reel
here
(Fig. 1), if you are interested.
The chart lengths
;
1200’ is 1.5 mil thickness (1 mil = one thousandth of an inch)
1800’ is 1 mil thickness.
2400’ is 0.5 mil thickness.
If you have any audio tape that is 0.5 mil (1/2 mil); It was fragile and hard to work
with in its day, and it is very fragile now. Some 0.5 mil tapes were 3600’ long.
RECORDS
The running times listed above represent the approximate maximum time available.
The average running time for a 10” Dia. 78 RPM record is about 3 minutes.
The average running time for 12” Dia. 33-1/3 RPM micro-groove records varies
from about 18 minutes to about 22 minutes (I’ve seen as much as 27 minutes).
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© Corey Bailey Audio Engineering
DO IT YOURSELF?
ANALOG TAPE
BAKING AUDIO TAPE
LUBRICATING AUDIO TAPE
MOISTURIZING ACETATE
TAPE
RECORDS (DISCS)
RECORD CLEANING
REPAIRING A BROKEN 78
FLATTENING A RECORD
ARTICLES:
Archival vs Restoration
A Little About Sound
Bit Depth
Conductive Paint
Mold
Optimizing your PC
Packing Records for
Shipment
People I have Known
Playing Records Wet
Playing a Wire Recording
Sample Frequency
Saving Your Family Video
The Alley
The Internet
The Ken Slater
Tapes
Time Charts
Transfer Stories
Tubes vs
Transistors
What Type of Wire?
Your Digital Data is at
Risk