Eventide is the originator of the digital profanity delay. Some of the first examples of this technology still haunt the Greater Media Detroit equipment archives. The Eventide BD955 units were single-channel, 2RU systems that could run as a master and slave for use in a stereo environment. They also possessed the unique capability to catch-up after being dumped, something that no tape loop ever could do. I never used that delay to its full potential because ramping was so slow and quite often objectionably audible. Also, the early delay unit possessed only seven seconds of delay, meaning operators had to be good and lucky to keep callers' foul tirade from finding its way on the air.
Considering the technology of the day (1977), Eventide's BD955 was a fine machine that found its way into many air-chains. In the post wardrobe-failure United States of today, we find ourselves wanting much more from a delay unit. If the FCC's policy and enforcement is not enough, many stations are forced to install delays to meet compliance with corporate mandates. Since Ms. Jackson's solar-clad protuberance was exposed the world over, several delay manufacturers found themselves in the enviable position of not being able to churn them out fast enough. These days delays offer superlative audio performance, nearly inaudible ramping, and some other cool features like the on-the-fly edit provided by a press of the cough/sneeze button and the ability to be dumped in steps so as not to leave the airchain with an unsafe amount of delay.
Performance at a glance
Word clock input
AES3 and analog I/O
Multiple dump operations
80 seconds of delay
Panic feature for audio fill after full dump
Optional extended remote control
Micro delay adjustment
Parallel remote control
The advancement of this technology is largely possible because of the reduction in scale and power requirements of random access memory. Eventide's latest product has enough for 80 seconds of stereo audio to be watchfully metered through in a bucket brigade fashion — first in first out. That would have taken a serial/parallel chain of some 22 of the original Eventide delay units.
In addition to building a state-of-the-art profanity delay, Eventide has looked to the future for its flagship model and included a precision delay mode that allows their BD600 to be used as a synchronization delay for use in HD Radio applications. This compelling new feature, called Micro Precision Fixed Delay, allows the station to separate the analog audio path from that of the digital. If you have HD Radio installed you no doubt recognize the advantage of having a stand-alone delay product to handle the digital time alignment. Since very early in the installation of HD Radio at my stations, I realized that having the stations' analog signal running through a PC (which the HD Radio signal generator undeniably is) made me a restless sleeper. You are just one CPU hang away from dead air. Another downside to that is the Ibiquity-designed delay internal to the signal generator can't profit from the years of experience gained developing delays that Eventide obviously possesses. That means that ramping in and out of delay is either agonizingly slow or clearly audible. Additionally, with the IBOC signal generator operating at minimum delay, a skip is still heard when taking the HD Radio signal generator in and out of the analog audio circuit. By contrast, the Eventide BD600 can slide itself inline and ramp up to a precision delay setting and then back again without anyone being the wiser.
Put into use
There are a number of places where a delay can be inserted to accommodate the alignment for digital. The Orban Optimod-FM 8500 includes a precision delay so that a user can accurately align the analog and digital signals. I've had success with the 8500 and found alignments as close as one sample (according to my friends at Ibiquity who possess a computer to measure such things). The 8500 seems like the perfect solution until you consider that it offers no way to ramp itself up or down, nor does it allow the user to choose distinctly different audio processing between the analog and digital streams. The Eventide BD600 placed at input to the analog stereo generator opens the possibility of processing the digital and analog signals differently and allows the station to make seamless transitions between time-aligned and non time-aligned operation.
Setup and operation of the BD600 is easy. The unit offers analog and AES3 digital connections as well as a word clock input and output. The BD600 comes in two flavors: one with basic remote control capability and one with an extended remote control. The latter includes a delayed parallel remote control loop-through that can be used to delay simple contact closure remote control commands by the exact amount that the audio is delayed, as well as a synchronized RS-232 loop-through useful for aligning RBDS generating equipment or automation equipment. Configuration is fairly straight forward after having a look at the manual.
I would have preferred the inclusion of a small LCD dot matrix display instead of the LED segment display for setup. The large LED, which is fine for display of the delay time, is forced to do double duty for setup operations and its displays are sometimes cryptic making it necessary to refer back to the manual for clarity.
Another Eventide innovation is the Compact Flash card slot used for storage of audio files, which the unit can playback while simultaneously building delay. Also offered is the ability to control the unit via an RS-232 serial connection to a computer, though no client software is offered.
On the whole, Eventide's BD600 is a terrific product that is ideal for HD Radio synchronization and profanity delay applications. I'll bet the producers of a certain football halftime show wish they would have had command of a dump button capable of censoring Ms. Janet.
Kernen is chief engineer of Greater Media Detroit.
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