was a rarity. Early on, some 78 rpm records had larger holes in freebie marketing schemes that sold a phonograph cheaply, but required purchase of compatible discs at full-price. Multi-hole records Some records had more than one hole in the label area. Busy Bee, in a marketing scheme similar to Standard et al. would employ a second cut-out area. This allowed the Busy Bee disc to also be played on a standard phonograph in addition to the proprietary format sold by the O'Neill-James Company. Many blank acetate discs have multiple holes (usually three or four) intended to prevent slippage during cutting. NON's Pagan Muzak (Gray Beat, 1978) is a one-sided 7-inch with multiple locked grooves and two center holes, meaning each locked groove can be played at two different trajectories as well as any number of speeds. The original release came with instructions for the listener to drill more holes in the record as they saw appropriate. Later pressings of the release were made only with one standard center spindle hole. Unusual grooves "Trimicron" discs Developed in the mid-1970s by the firm MDR (Magnetic Disc Recording), the Trimicron record enjoyed a brief success. The principle was to remove the empty space between each groove. On average, this empty space is as wide as two grooves, and because of this, its removal effectively triples the duration of the recording that could be engraved (on average, 55 minutes on a 33 rpm record). The Trimicron process was created by Dr. Rabe, a music lover in his spare time, and was originally intended for classical music listeners who could not stand having to flip a record in the middle of a piece. For example, all six Brandenburg concertos could fit on one Trimicron record. However, this process suffered from a major problem: the finer groove decreased the dynamics and the level of recorded signal by nearly 40 percent. It is therefore necessary to play Trimicron records on silent, high performance turntables, equipped with new diamonds and very high performance. Almost 30 Trimicron records were released, though copies are nowadays rare, especially in good condition. Multiple bands Some records are cut with completely independent bands on the same side. In this case, the bands appear as separate tracks on the record and are not intertwined as with parallel grooves (see below). This has most often been used on educational records but is also sometimes