IEC 60098-2020 pdf download.Analogue audio disk records and reproducing equipment (IEC 60098:2020).
6 The groove
6.1 Direction of groove modulation
The stereophonic groove shall carry two channels of information. The two channels shall be recorded in such a manner that they can be reproduced by movements of a reproducing stylus tip in two directions at 90° to each other, and at 45° to a radial line through the stylus tip and the centre of the record; these movements shall be tangential to, or lie in a plane through the stylus tip and the record centre, inclined at an angle of +5 0 20 ° anticlockwise to the normal to the record surface through the stylus tip as viewed towards the record centre (vertical tracking angle). The resulting modulation shall be optimum for reproducing styli having a rake angle of between 0° and −5° (for detail, see Figure 3).
The monophonic groove shall carry one channel of information. It shall be recorded on both groove walls in such a manner that it can be reproduced by lateral movements of a stylus tip as described above. 6.2 Arrangement of stereophonic channels
6.2.1 Channel orientation The right-hand channel, as viewed by the audience, shall be recorded on the outer groove wall, the lefthand channel on the inner groove wall.
6.2.2 Channel phasing The phasing of the two recorded signals shall be suitable for reproduction on two-channel equipment so connected that movement of the reproducing stylus tip along the radial line through stylus tip and disk centre (as with a monophonic record) produces in-phase sound pressures at the lefthand and right-hand loudspeakers.
6.2.3 Channel levels The levels of the two recorded signals shall be suitable for reproduction on two-channel equipment, of identical channel gain, so connected that movement of the reproducing stylus along the radial line through the stylus tip and disk centre (as with a monophonic record) produces equal sound pressures at the lefthand and right-hand loudspeakers.
6.2.4 Channel polarity The polarity of the two recorded signals should preferably be suitable for reproduction on two- channel equipment so connected that movement of the reproducing stylus tip along the radial line through stylus tip and disk centre in a direction away from the disk centre shall produce compression in front of the left and right-hand loudspeakers similar to that produced by the live programme source.
6.3 Groove
dimensions
Instantaneous top width: 30 µm (0,01 2 in) minimum
Bottom radius: 8 µm (0,000 32 in) maximum
Included angle: (90 ± 5)°
6.4 Lead-in groove
The pitch of the lead-in groove shall be (1 ,2 ± 0,4) mm. The groove width shall be (60 ± 1 0) µm.
6.5 Outer diameter of recorded surface
The recorded surface shall start with at least one turn of plain groove and have a maximum outer diameter of:
• 292,6 mm for types 3033 and 3045;
• 241 ,8 mm for types 2545 and 2533;
• 1 68,3 mm for types 1 733 and 1 745.
6.6 Eccentricity of groove spiral
The distance of the centre of the groove spiral to the centre of the centre hole shall be not more than 0,2 mm.IEC 60098 pdf download.