Time Code – Andrew Berliner

The twelve-bit analog to digital converter using high speed multiplexing techniques, samples and digitizes the control voltage of each of the six submaster faders, 40 input faders, and four line control faders in order. The sequential sampling produces a flow of words. A word is the digitized representation for the number of dB attenuation from unity gain for one time period.

First the six words representing the value (dB attenuation) of the six submasters are stored in the six submaster memories.

Then, the Channel #1 fader word is entered into the adder. If any of the six submaster selector switches are selected, the values of those submasters are recalled from memory, and also entered into the adder. A word representing the sum of the channel fader and all of the selected submasters results. Each channel is sequentially processed so that one console scan results in the flow of 44 data words from the adder.

The flow is then processed by the exponential memory. Here, on a plug-in circuit board the 12 ROM’s scale the fader taper. The ability to adjust the dB per inch of travel of all faders while a fringe benefit of digital processing is a unique feature of the Crystalab system.

The function of the Data Multiplexer circuitry is the heart of this high-speed data management system. It is the power of the Read/Write switch. The Data Multiplexer has two data inputs: one from the console faders and the other the “from disc” buffer. The 44 word scans are synchronized such that the Read/Write switch on each channel selects between the two “word 1’s”. two “word 2’s”, two “word 3’s”, and so on until one of all 44 pairs of words have been selected. This composite data is directed to the output circuitry and to the input of the “to disc” buffer.

The output circuitry takes the flow of composite data and directs the 44 words to the 44 Programmable Parametric Attenuators as well to the LED dB attenuation readout displays of the fader.

The update power of this system effectively allows the operator to alter any of the 44 channels for a period as short as one thousandth of a second without affecting or changing any other channels. The selective Read/Write of each channel on each scan provides a powerful tool.

The buffer memory consists of two 11,000 word Randon Access memories. Each RAM has 250 locations of 44 words. The “to disc” RAM receives data from the output of the data multiplexer. At the start of a time zone, say, T200, (note: which is the “T200 time:” referenced in the cartoon panel below) the 44 words of each console scan are sequentially stored, in order, at each location. Each successive console scan addresses the next location. Each time zone is 250 msec. At the end of the 250th console scan the “to disc” RAM is full and all information is shifted to disc in lump and stored in the time zone related block, in this case T200. When T201 starts, the “to disc” RAM is empty and again begins to fill up.

This sequence is repeated for each 250 msec time zone. In this way data is entered into RAM in real time but shifted to disc as one block. Meanwhile, just before the start of T200, the block of data at disc location T200 is shifted to the “from disc” RAM as a chunk. When T200 starts, each location is sequentially emptied exactly as it had been entered. The first location that had been filled is also the first to empty. The 44 words of each scan are directed to the “from disc” buffer input of the Data Multiplexer.

At any given instant both RAMs are processing the same time zone. The “from disc” is emptying into the Data Multiplexer input while the “to disc” RAM is filling up from the Data Multiplexer output.

Time Code

The Crystalab proprietary Time Code System allows the synchronization of the master audio tape, console, and disc memory systems.

The time code signal generated in the encoder is recorded on the audio tape. As the tape is replayed, each time code reading is interpreted by the time code reader and is translated into a four digit number. The four digit numbers are successively incremental such that 0000 is followed by 0001, 0002, and so on. There are four time zones each second; 2400 time zones for a 10 minute period.

The time code signal itself is a modulated 20kHz sine wave recorded at a level as much as 35 dB below reference. One of the problems of existing time code systems is the interference between it and the audio information on adjacent tracks. The unique feature of the Crystalab Time Code System is that it does not require a separate track. It’s supersonic frequency and low recorded level make it inconspicuous on the bass or bass drum track. The time code readings are insensitive to dropouts, spurious pops or clicks, and tape speed variations.

Overall, the gap between sophisticated electronics and user ease of operation has been narrowed. No longer is “state-of-the-art” a synonym for complicated and difficult to use because the digital control of audio offers the creative engineer a chance to control the equipment and not be controlled by it; it is the mixer’s musical instrument which is easily played with understanding and feeling.

Designed as an integral element of a complete 24 track mixing studio, Crystalab’s new and unique circuits, fabricated with only military grade components and gold contacts on all switches and connectors, underscore the handcrafted quality. Machined aluminum framework and engraved panels, as well as burl woodwork, add strength and beauty to a system where high performance and super-reliability are the first design specifications.

The purpose of Crystalab is to enhance the artistry and technology of music recording systems.

The tremendous design effort invested in this project is representative of the creativity that is the essence of the music business.