[78-L] Noisy vinyl

[Chris Zwarg]

>
>The whole reason for going to slower speeds was to get rid of surface 
>noise. Theoretically, a 78 should have better sound, except for this.

The reason for slower speed was (obviously) longer playing time, and making this practicable led to the development of quieter pressing materials, as shellac - barely adequate at 78rpm with wide grooving - was unbearably noisy at 33rpm with the narrower groove necessary to transmit high frequencies in spite of the low speed.

All other things equal (groove width, recorded level, pressing material) higher speeds are always better. The noise level does NOT rise with the higher speed; on the contrary, small defects will have less influence on the sound quality as they obscure a relatively smaller part of the engraved soundwave, and the distortion typical for many slow-speed discs, arising from the problems of tracking very narrow and zig-zaggy modulations with a somewhat rounded stylus, all but disappears at 78rpm. For this reason, some series of background music and sound-effects discs for broadcasting purposes used 78rpm well into the 1960's; with microgroove-cut and pressed on quality vinyl, these records easily leave most LPs of similar vintage behind. 

The late 1970's saw a similar development, namely the 45rpm 12-inch "Super Sound" or "Maxi" single, originally intended for DJs but also widely issued to customers during the 1980's and 1990's. These usually sound much better than the same tracks issued on either 7-inch singles or LP albums, and are more resistant to wear and mistracking.

Chris Zwarg