Alec97 Posted March 12, 2015 Share Posted March 12, 2015 Hi folks,We want to record the communications on our cans system, we have tried recording with a voice recorder to one of the headsets but it's not clear enough for our liking. So any solutions to do this ? It's a standard canford audio system with the new tec pro packs and headsets. Cheers Alec Link to comment Share on other sites More sharing options...
the kid Posted March 12, 2015 Share Posted March 12, 2015 There are a few old topics about http://www.blue-room.org.uk/index.php?showtopic=15357 But why? Link to comment Share on other sites More sharing options...
TomHoward Posted March 12, 2015 Share Posted March 12, 2015 We have a cable that is run between our comms line and a rack mixer that provides a comms feed for the show relay for certain situations, which is a straight XLR cable which drops the power line of the comms, and adds a small capacitor in series with the audio line to block the DC used for call, probably not an advised method but seems to work fine Link to comment Share on other sites More sharing options...
timsabre Posted March 12, 2015 Share Posted March 12, 2015 We have a cable that is run between our comms line and a rack mixer that provides a comms feed for the show relay for certain situations, which is a straight XLR cable which drops the power line of the comms, and adds a small capacitor in series with the audio line to block the DC used for call, probably not an advised method but seems to work fine This is how I've done it before. Put a 100nF capacitor in series with pin 3 of the comms line. Pin 1=Gnd. This gives you an unbalanced line level signal. Pin 2 has 24V on it so ignore that. Link to comment Share on other sites More sharing options...
Tim gregory Posted March 12, 2015 Share Posted March 12, 2015 We have a cable that is run between our comms line and a rack mixer that provides a comms feed for the show relay for certain situations, which is a straight XLR cable which drops the power line of the comms, and adds a small capacitor in series with the audio line to block the DC used for call, probably not an advised method but seems to work fine This is how I've done it before. Put a 100nF capacitor in series with pin 3 of the comms line. Pin 1=Gnd. This gives you an unbalanced line level signal. Pin 2 has 24V on it so ignore that. Out of interest can you inject an external signal as a mic in a similar way without a belt pack? Thanks, Tim Link to comment Share on other sites More sharing options...
timsabre Posted March 12, 2015 Share Posted March 12, 2015 Out of interest can you inject an external signal as a mic in a similar way without a belt pack? No, you need the proper hybrid circuit to inject a signal onto the line. It's just an opamp circuit, but a bit weird to understand - have a look at the Bluecom project. Link to comment Share on other sites More sharing options...
Jon Wiles Posted March 12, 2015 Share Posted March 12, 2015 Yes you canI have a cable that allows a signal (from say a desk) into the comms master station. No electronics, it just works Link to comment Share on other sites More sharing options...
ddproduction Posted March 12, 2015 Share Posted March 12, 2015 Allows a signal?Could you elaborate please? Link to comment Share on other sites More sharing options...
timsabre Posted March 12, 2015 Share Posted March 12, 2015 Going into the comms master station is a different situation to just connecting directly to the intercom line. Many master stations have a line in socket for this purpose or you can go in on a headset connector. If you connect directly to the comms line you mess up the impedance, all the sidetone goes funny and it doesn't work properly any more. But sometimes you might get away with it... Link to comment Share on other sites More sharing options...
paulears Posted March 12, 2015 Share Posted March 12, 2015 For years I simply did what was explained above, dropped the voltage line, and applied the audio to pin 2 and the comms ground to pin 3 - NOT 1. Tecpros and others have real issues with remote grounding - and using the differential inputs worked fine on Soundcraft and Yamaha mixers. I used this trick on the theatre desk so I could have the desk cans provide me with comms too, and not try to wear two pairs for the bits where comms and pfl'ing were needed at the same time. It was even occasionally useful for putting the comms live to the PA - with a bit of care and pre-planning. Handy for those emergency type announcements that you can't plan for. You can also use it to stick the comms line into an IEM transmitter - which I do a lot! Link to comment Share on other sites More sharing options...
TomHoward Posted March 13, 2015 Share Posted March 13, 2015 Good point about the grounding. Our comms PSU is in the same rack as the line mixer so they no doubt share a common ground and we get away with it but would be worth keeping it floating if you are breaking out a long way from the master station / comms PSU. Link to comment Share on other sites More sharing options...
Tim gregory Posted March 13, 2015 Share Posted March 13, 2015 Out of interest can you inject an external signal as a mic in a similar way without a belt pack? No, you need the proper hybrid circuit to inject a signal onto the line. It's just an opamp circuit, but a bit weird to understand - have a look at the Bluecom project. Thanks yeah that is what I expected. I am trying to link a wired Tecpro system with an oldish Anchor Portacom wireless comms system. The Anchor Portacom system doesn't have a base station so I linked the headset output of the Tecpro beltpack to the mic input on the Portacom set, with a resistor in line. I can also link the other way (Portacom headphone out to Tecpro mic) but if I try and do both at the same time it causes all sorts of noise issues on both systems.It was a little while ago that I attempted this so can't remember the exact issues. It may be that isolating transformers would sort this. The reason for doing this is so that I can have one completely wireless camera on the comms system but the rest of the comms are best off wired. Tim Link to comment Share on other sites More sharing options...
timsabre Posted March 13, 2015 Share Posted March 13, 2015 I am trying to link a wired Tecpro system with an oldish Anchor Portacom wireless comms system. The Anchor Portacom system doesn't have a base station so I linked the headset output of the Tecpro beltpack to the mic input on the Portacom set, with a resistor in line. I can also link the other way (Portacom headphone out to Tecpro mic) but if I try and do both at the same time it causes all sorts of noise issues on both systems.It was a little while ago that I attempted this so can't remember the exact issues. It may be that isolating transformers would sort this. The headset out on tecpro is probably a bridge amp (both +ve and -ve sides driven opposite ways) so if you connect both mic and headphones you will be shorting one side of the headphone amp to ground, this will not be a good thing. Isolating transformers would probably fix it, or probably taking just one side of the headphone output would work as well. DC blocking capacitors would also be a good idea Link to comment Share on other sites More sharing options...
Tim gregory Posted March 13, 2015 Share Posted March 13, 2015 The headset out on tecpro is probably a bridge amp (both +ve and -ve sides driven opposite ways) so if you connect both mic and headphones you will be shorting one side of the headphone amp to ground, this will not be a good thing. Isolating transformers would probably fix it, or probably taking just one side of the headphone output would work as well. DC blocking capacitors would also be a good idea Thanks, that is helpful. I will try and look at it again soon. Tim Link to comment Share on other sites More sharing options...
J Pearce Posted March 13, 2015 Share Posted March 13, 2015 There is a canford box built to do this sort thing, it adapts to 4 wire, so that you have individual headphone and mic ports, I seem to recall it has some padding built in too. I think it is the AD913. Link to comment Share on other sites More sharing options...
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