CircuitWerkes News

This page contains information about new CircuitWerkes products, updates or special promotions that may be valuable to our customers. All CircuitWerkes products are now, and have always been, Y2K compliant.

05-15-01
About subaudible tones to control Internet streaming (FTRA & local spot insertion)
We've had several calls from folks interested in controlling their Internet commercial streams via subaudible tones. This is a handy way to keep those AFTRA spots off of the Internet. The most frequently asked question is: Can I just record subaudible tones onto my hard drive and then replay them, prior to an AFTRA spot, using a SUB-03 to decode them and control the switching of the audio? The answer is: We don't recommend it because the subaudible encoders do more than just produce the tones. They must also filter out any subaudible program content before inserting the tones. If you don't filter out subaudible content, you risk having those frequencies false trip your decoder with random audio which could cause you to switch your feed off accidently, or worse, prematurely turn the feed back on while the AFTRA spots are still playing. If you are planning to try this, we suggest that you use 25&35 Hz combo tones to return your Internet feed to regular programming. Since dual tones are more robust than single tones, there's far less chance of false tripping.

On a related note:
We've been asked about modifying our subaudible encoders and decoders to use 19 and 27 Hz. This request is apparently related to staying clear of someone's patent which spells out the use of 25 and 35Hz tones for Internet streaming control. Given that subaudible tones have been used for many years for virtually all kinds of controls, ranging from tapes to modern digital connections, it would seem that such an "invention" should be obvious and therefore, perhaps questionable in its validity. However, if you want to avoid possibly abusing someone's Internet patent, you'll be happy to note that the SUB-03 decoders can be retuned for 19 & 27 Hz without modification. The SEN-6 encoders require new firmware which is available from us at a cost of $25.00. The SEN-6 will work without retuning its filters, but for best performance those should be done as well.