The amount of recording time that can be accommodated on a vinyl record depends on several factors. These factors include record speed, record diameter, groove width, groove depth, recording level, and program material. The following chart is based on the RIAA Standard Reference Level at standard groove widths and depths. Recording level affects the width of the groove. Faster rotation speeds can accommodate higher levels because they can be achieved with a narrower groove. As a general rule of thumb, for a 12" record at a speed of 331⁄3 rpm, you lose about 1dB in volume for for each additional minute per side. Because lower frequency material requires a wider groove, music that is heavy in bass should be cut at a lower level. For loud dance music, the groove is sometimes cut deeper. Typical levels for vinyl records are:
Record Diameter | ||||
---|---|---|---|---|
Speed (rpm) |
Level (ref to SRL*) |
7" | 10" | 12" |
331⁄3 | 0 dB | 6.5** | 13.0 | 20.0 |
331⁄3 | -3 dB | 7.5 | 17.0 | 24.0 |
331⁄3 | -6 dB | 9.5 | 19.0 | 28.0 |
45 | +3 dB | 4.0 | 8.0 | 10.5 |
45 | 0 dB | 5.0 | 10.0 | 13.5 |
45 | -3 dB | 6.0 | 12.0 | 16.0 |
78 | +3 dB | --- | 4.5 | --- |
78 | 0 dB | --- | 5.5 | --- |
78 | -3 dB | --- | 6.5 | --- |
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* SRL = RIAA Standard Reference Level
** Not recommended due to potential distortion