Webcasting Voice Backup

[jeromer7]

Useful information if you decide to go with this solution:

1. Our FM group initially couldn't find these Emtech devices in their ordering system. Tell your FM person that they need to place the order through the Church MTS Department.
2. These Emtech devices are designed to be installed between your telephone handset and the telephone base. Some phones are not compatible with these devices, so if it doesn't work when you test, try a different phone. Also, Princess type phones, with the buttons in the handset, will not work at all. Use a classic phone that has the buttons in the base.

Our stake is hosting a fireside tomorrow evening with a member of the Seventy. I was asked to Webcast it to outlying stakes in our Coordination Council. It is my first experience with setting up a Webcast. All is in place except the audio backup. The information here and on RKATS has been invaluable.

I obtained the recommended Mackie VLZ3 mixer and Emtech EJ-R and put them in place yesterday. Connected the audio source and called my cell phone from the phone in the satellite closet. No audio, but did get clicking if I unplugged the phono plug and the lights at the lower right of the mixer showed there was sound.

Read the section of the quoted post above and determined the problem was the princess style phone. Went back today and put one of the office phones in the loop instead of the princess phone. Called my cell and again, no audio. Again the lights on the right of the mixer show that there is sound at the mixer.

It was interesting that the handset mic didn't pick up my voice when I talked into it regardless if the mute switch on the EJ-R was set at Mute or Off. If I talked into my cell, I could hear myself in the handset speaker.

The quoted post says not all phones are compatible. I guess now, the theory is that the desk phones in the stake center are the problem. Or can anyone see where I'm not doing something right?

[russellhltn]

Looking at the EJ-R specs, I notice that it says the input should be a stereo headphone. In that case, if you feed it with balanced audio, you'll get nothing. (Because the "left" and "right" "channel" will be 180 degrees out of phase.) It may or may not work well with a mono (two-wire) connection. Lastly is levels. Make sure the mixer is pumping out closer to 0 VU, not way down -20. And it has to be line/headphone level, not mic level.

[jeromer7]

Thanks for your quick reply Russell. However, the spec sheet at the Emtech site (http://www.emtechelectronics.com/medias ... /EJR_1.pdf), page 2, Inputs, lists '1/4" Mono Phone Jack'.

[jeromer7]

Spoke a bit too soon. I looked at the "Manual" link and the specs there do indeed say it is a '1/4" Stereo Phone Jack'. (http://www.emtechelectronics.com/medias ... ctions.pdf)

I probably have a mono so will get a stereo and see if it makes a difference.

[russellhltn]

the spec sheet at the Emtech site (http://www.emtechelectronics.com/medias ... /EJR_1.pdf), page 2, Inputs, lists '1/4" Mono Phone Jack'.

I was reading the user manual. It says "stereo". I wish there was a schematic, because then I'd have a better understanding of what could be going on. (Personally, I'd prefer it to be a line-in, balanced or unbalanced. If I have a headphone feed, I'm probably going to want to use it for MY headphones, not as an extra output.)

I do know this: The EJ-R is a passive device. All the power needed to drive the phone line will have to come from the mixing board. That's going to take a strong line level, maybe more (which may explain headphone input). Anything that kills the level could leave you with something too weak to work.

[danpass]

Called my cell ...

It appears that you are getting to the bottom of your issue with Russell's help.

Your mention of using your cell phone brings to mind another caveat that we discovered in our testing. This has nothing to do with the issue you are experiencing.

In addition to items 1 and 2 in my previous list, I would add:

3. Don’t use a mobile phone on the receiving end of the audio backup.

We webcast our Stake Conferences from our Stake Center to two other meetinghouses. We use the EJ-R to supply the audio feed into a conference bridge. The two remote locations use the TTAIB device to supply the audio from the conference bridge into their respective building sound systems. Once we had phones that were compatible, all our testing of both voice and music over this audio backup solution was successful. We test all of this along with our webcast equipment during the week leading up to each local stake conference.

Prior to a subsequent Stake Conference, during testing, one of the remote sites reported that while the organ was being played, the backup audio kept cutting in and out on their end. Regretfully, we didn't determine the cause of this problem until after a problem plagued webcast of a Stake Priesthood meeting months later.

My A/V assistants in that building had begun using their cell phones to call into the conference bridge, rather than the phone and landline connection which we had installed in the chapel for this purpose. When I found this out, I asked them to switch back to using the landline. This eliminated the problem.

Until we figured this out, they had both tried different cell phones (IOS and Android), on different carriers, as well as patching them into both the TTAIB as well as their crab box. In all cases, the audio would start cutting in and out whenever organ music began.

[russellhltn]

Your mention of using your cell phone brings to mind another caveat that we discovered in our testing.

Two thoughts come to mind:

The vocoder (the software that digitizes the sound) is tuned for voice, not music. That can make some things like music sound really, really bad.

The second is that I've observed that there's some kind of echo canceling, or other processing that may mute a weak signal if there's too much background noise at your end.

[rmrichesjr]

the spec sheet at the Emtech site (http://www.emtechelectronics.com/medias ... /EJR_1.pdf), page 2, Inputs, lists '1/4" Mono Phone Jack'.

I was reading the user manual. It says "stereo". I wish there was a schematic, because then I'd have a better understanding of what could be going on. (Personally, I'd prefer it to be a line-in, balanced or unbalanced. If I have a headphone feed, I'm probably going to want to use it for MY headphones, not as an extra output.)

I do know this: The EJ-R is a passive device. All the power needed to drive the phone line will have to come from the mixing board. That's going to take a strong line level, maybe more (which may explain headphone input). Anything that kills the level could leave you with something too weak to work.

If a schematic would still be helpful, there's a hand-drawn schematic someone else posted in 2010 in a thread titled "Care and feeding of the EJ10". Here's the URL to the schematic: https://tech.lds.org/forum/download/file.php?id=719

I'll second (or third or ...) the advice earlier in this thread to use plain, passive landline phone rather than cell phone. In fact, you can likely hang up the phone once the connection is made. The crab box's telephone circuit has low enough resistance it should keep the phone call active. That should give you better SNR and better levels. If you do that, there will be a loud click and a change in level when you hang up the phone.

Another suggestion would be to 'Y' the headphone output from the mixer to feed both your headphones and the crab box. The mixer's headhone output should have low enough output impedance to feed both.

HTH

[russellhltn]

If a schematic would still be helpful, there's a hand-drawn schematic someone else posted in 2010 in a thread titled "Care and feeding of the EJ10". Here's the URL to the schematic: https://tech.lds.org/forum/download/file.php?id=719

That's the "10". We need the "R".

[rmrichesjr]

That's the "10". We need the "R".

Ahhh, I didn't look closely enough at the picture on the spec sheet. Sorry for that error.

I'm a little surprised to see the tap done on the RJ-6 connection between the base and handset. There is not much standardization in the wiring of that connection, in contrast to the very well standardized RJ-8 line between base and switching equipment. Most headsets I have used on the RJ-6 connection have a big switch with at least six positions to handle various standards, and there are still some combinations of phones and headsets that can't be made to work together.

Still, I would be fairly confident that the non-telephone side of the EJ-R has essentially the same circuitry as the path between telephone RJ-8 and line-level input on the EJ-10. If there is still time to test potential solutions, I'd try that hypothesis if it were me. IIRC, standard telephone levels are +8 or +12dB above 1mW into 600 ohms. That would be on the order of 2-3 volts of signal. That's considerably higher than most consumer-grade line-level outputs. I'd favor using a headphone output to drive the EJ-R.