Talkback via firewire? at DVinfo.net

Mark Harmer · July 4th, 2010, 06:19 AM

I'm doing some live internet TV in August as an experiment, and have 2 x XHA1 cameras. We'll be taking a live feed (video only) in standard definition DV format from each camera via firewire (video only) to a PC which has a software vision mixer. The audio is coming into the PC separately via an analogue mixer.

We know this part all works - using firewire extenders, I've been able to get each camera 65m away!

HOWEVER, it is pretty much essential that I can rig up some sort of talkback system so the camera operators can hear instructions, preferably without having to rig extra cables.

The mad scientist way to do this would be some sort of FM transmitter at the vision mixing position with radio headphones, but I'm wondering if there's a magic way of feeding audio down the firewire such that it can be picked up and monitored at the cameras while the video is going in the "other direction", from the cameras to the PC.

You appreciate this is just an experiment at this stage but if anyone's done this please tell me how!!

G. Randy Brown · July 4th, 2010, 02:59 PM

Would cell phones with bluetooth work?

Allan Black · July 4th, 2010, 03:17 PM

I've never heard of any set-up where you can send audio back via firewire as you describe.

From my tv experience, to provide the cameras with an audio feed including the directors calls means a separate cabled return from the control room.

To avoid the possibility of crosstalk I'd keep it out of your analogue mixer and use another smaller mixer. Also send a feed to your boom op?

The power cabling in the building comes into this, the newer it is the better and hopefully not in the centre of the city. Check if there's any transmitters within a mile or 2.
The longer you run the cables the more chance you have of earth loops and degrading the pix .. keep checking that at each step of the way. You probably have to run the cameras on their batteries to avoid this.
Cheers.

Mark Harmer · July 4th, 2010, 03:18 PM

G Randy Brown, that's certainly another possibility - if I can't get the talkback via firewire thing working. Thanks for the idea!

Allan Black, thanks for that thought - and good point about the power cabling. It's actually an old church in the country, and yes, we're definitely running the cameras on batteries but will certainly have to check for any problems. We're hoping to do a dry run anyway so keep the talkback ideas coming. I might get out the XHA1 to give it a try but I don't think it can do audio in one direction and video in the other, simultaneously, so I might have to try other things. This is to be honest, not a big budget production, more an experiment!

Bill Watson · July 4th, 2010, 04:00 PM

Since you're not covering much distance, the easiest way would be a set of cheap UHF two way radios from Radio Shack I would think. You can get them with mic/headphone sets and some are voice activated.

Mark Harmer · July 4th, 2010, 04:10 PM

Bill, thank you, another top idea!!

Mark Harmer · December 7th, 2010, 06:05 PM

Bill, I know this is a few months down the line, but I did what you suggested - actually bought 4 walkie talkies, each with headsets, and had three (one for each camera) plus one for me to talk into. It worked really well. Thanks for the idea!

Mark

G. Randy Brown · December 7th, 2010, 06:09 PM

what model, how much por favor?

Les Wilson · December 7th, 2010, 06:29 PM

I've used Motorola Spirit GT radios filming football games for a number of years. The camera ops listen to the play call and know where the play is going.

Radios are in my opinion just barely adequate for an occasional thing. They don't hold a candle to a crystal clear quiet real intercom such as Clear-Com or Production Intercom.

The key thing with any of the Family Radios is that they support a headset with a mic and Push-To-Talk activation. The VOX activation is, IMHO, unreliable.

Mark Harmer · December 8th, 2010, 04:50 PM

Quote:

Originally Posted by G. Randy Brown

what model, how much por favor?

These were Cobra radios and came with mic / earpieces so that people could keep them in their ears throughout. I'm in the UK and bought mine from Pixmania for £99 for a set of 4, which I thought was pretty good. The range and quality were really great for the venues we were using. They run on 4 x AAA batteries and come with a base unit that charges a pair of walkie-talkies. Battery life was about 2.5 hours on a charge, which was fine for our needs. Can't remember the actual model but it was 975-something or other. They're in a box at the moment.

Bill Watson · December 8th, 2010, 05:11 PM

Pleased to hear it worked for you. Often the simplest way is the best.

Mark Harmer · December 13th, 2010, 08:17 AM

That's so true! Same with audio / lighting - the more mics / lights you have, the more problems!!

July 4th, 2010, 06:19 AM	#1
Mark Harmer Regular Crew Join Date: Nov 2006 Location: Moreton in Marsh, United Kingdom Posts: 96	Talkback via firewire? I'm doing some live internet TV in August as an experiment, and have 2 x XHA1 cameras. We'll be taking a live feed (video only) in standard definition DV format from each camera via firewire (video only) to a PC which has a software vision mixer. The audio is coming into the PC separately via an analogue mixer. We know this part all works - using firewire extenders, I've been able to get each camera 65m away! HOWEVER, it is pretty much essential that I can rig up some sort of talkback system so the camera operators can hear instructions, preferably without having to rig extra cables. The mad scientist way to do this would be some sort of FM transmitter at the vision mixing position with radio headphones, but I'm wondering if there's a magic way of feeding audio down the firewire such that it can be picked up and monitored at the cameras while the video is going in the "other direction", from the cameras to the PC. You appreciate this is just an experiment at this stage but if anyone's done this please tell me how!!

July 4th, 2010, 03:17 PM	#3
Allan Black Inner Circle Join Date: Sep 2006 Location: Sydney. Posts: 2,937	I've never heard of any set-up where you can send audio back via firewire as you describe. From my tv experience, to provide the cameras with an audio feed including the directors calls means a separate cabled return from the control room. To avoid the possibility of crosstalk I'd keep it out of your analogue mixer and use another smaller mixer. Also send a feed to your boom op? The power cabling in the building comes into this, the newer it is the better and hopefully not in the centre of the city. Check if there's any transmitters within a mile or 2. The longer you run the cables the more chance you have of earth loops and degrading the pix .. keep checking that at each step of the way. You probably have to run the cameras on their batteries to avoid this. Cheers. __________________ Drink more tap water. On admission at Sydney hospitals more than 5% of day patients are de-hydrated.

July 4th, 2010, 02:59 PM	#2
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	Would cell phones with bluetooth work?

July 4th, 2010, 03:18 PM	#4
Mark Harmer Regular Crew Join Date: Nov 2006 Location: Moreton in Marsh, United Kingdom Posts: 96	G Randy Brown, that's certainly another possibility - if I can't get the talkback via firewire thing working. Thanks for the idea! Allan Black, thanks for that thought - and good point about the power cabling. It's actually an old church in the country, and yes, we're definitely running the cameras on batteries but will certainly have to check for any problems. We're hoping to do a dry run anyway so keep the talkback ideas coming. I might get out the XHA1 to give it a try but I don't think it can do audio in one direction and video in the other, simultaneously, so I might have to try other things. This is to be honest, not a big budget production, more an experiment!

July 4th, 2010, 04:00 PM	#5
Bill Watson Major Player Join Date: May 2007 Location: Noosa Queensland Australia Posts: 248	Since you're not covering much distance, the easiest way would be a set of cheap UHF two way radios from Radio Shack I would think. You can get them with mic/headphone sets and some are voice activated.

July 4th, 2010, 04:10 PM	#6
Mark Harmer Regular Crew Join Date: Nov 2006 Location: Moreton in Marsh, United Kingdom Posts: 96	Bill, thank you, another top idea!!

December 7th, 2010, 06:05 PM	#7
Mark Harmer Regular Crew Join Date: Nov 2006 Location: Moreton in Marsh, United Kingdom Posts: 96	Bill, I know this is a few months down the line, but I did what you suggested - actually bought 4 walkie talkies, each with headsets, and had three (one for each camera) plus one for me to talk into. It worked really well. Thanks for the idea! Mark

December 7th, 2010, 06:09 PM	#8
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	what model, how much por favor?

December 7th, 2010, 06:29 PM	#9
Les Wilson Inner Circle Join Date: Jan 2004 Location: Boca Raton, FL Posts: 3,014	I've used Motorola Spirit GT radios filming football games for a number of years. The camera ops listen to the play call and know where the play is going. Radios are in my opinion just barely adequate for an occasional thing. They don't hold a candle to a crystal clear quiet real intercom such as Clear-Com or Production Intercom. The key thing with any of the Family Radios is that they support a headset with a mic and Push-To-Talk activation. The VOX activation is, IMHO, unreliable.

December 8th, 2010, 05:11 PM	#11
Bill Watson Major Player Join Date: May 2007 Location: Noosa Queensland Australia Posts: 248	Pleased to hear it worked for you. Often the simplest way is the best.

December 13th, 2010, 08:17 AM	#12
Mark Harmer Regular Crew Join Date: Nov 2006 Location: Moreton in Marsh, United Kingdom Posts: 96	That's so true! Same with audio / lighting - the more mics / lights you have, the more problems!!