Can I split the output of the podium mic?

Conversations around originating a webcast for conference, including cameras and mixers.
kwillisjr
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Can I split the output of the podium mic?

Postby kwillisjr » Mon Sep 10, 2012 8:11 pm

We just had a failed webcast this past Sunday (yesterday). The problem sounded like way overmodulated audio. I have not yet had the time to try to figure out where and / or why the problem existed but I'm wondering if it is possible to split the signal at the mic input under the podium and bypass the buildings sound equipment. One feed would feed the building sound system and the other would be a dedicated feed to the webcast communicator. I don't know the model of the microphone but can get that tomorrow. I know that the 3 mic wires connect (under the podium) to one side of a small (I assume) amplifier (little black box) and exit out the other side of the box via a cable with an XLR connector on it that feeds the building sound system. I'm wondering if it's possible to split this here. What parts / equipment would I need to make this interface with the webcast communicator?
Thanks,
Ken

russellhltn
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Postby russellhltn » Mon Sep 10, 2012 8:39 pm

I wouldn't. Too many ways that could go wrong and impact the local sound system. And to do it right calls for buying a mic splitter (don't just use a "Y" cable) which is actually more expensive then fixing the problem.

I think it's far simpler to put some needed attenuation on the line feeding your webcast communicator. It also prevents you from running afoul of the FM group. They don't like it when people modify the sound system since they are responsible for it's proper operation.
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Mikerowaved
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Postby Mikerowaved » Mon Sep 10, 2012 8:46 pm

Ken,

This stuff can truly be frustrating at times, but before getting out the diagonal cutters you might want to review this Help with webcast issues thread, where some great suggestions were offered to others who experienced a similar problem as yours.

There's also a wealth of information located in the Meetinghouse Webcast Audio page of the Wiki.

You might also want to elaborate a bit on your existing setup and what kind of testing was done beforehand. This will give us an idea of how best to offer assistance. Sometimes all that's needed is a simple audio mixer at the webcast site to be able to adjust the audio levels on-the-fly.
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harddrive
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Postby harddrive » Tue Sep 11, 2012 5:55 am

If I were you, I would contact the FM group about having a cable run from the chapel amplifier to the webcasting unit. We have done that in my stake and I get great audio directly off the main amplifier for the chapel.

Paulbb1
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Suggestion to control sound input to wevcast capture card

Postby Paulbb1 » Tue Sep 11, 2012 5:09 pm

kwillisjr wrote:We just had a failed webcast this past Sunday (yesterday). The problem sounded like way overmodulated audio. I have not yet had the time to try to figure out where and / or why the problem existed but I'm wondering if it is possible to split the signal at the mic input under the podium and bypass the buildings sound equipment. One feed would feed the building sound system and the other would be a dedicated feed to the webcast communicator. I don't know the model of the microphone but can get that tomorrow. I know that the 3 mic wires connect (under the podium) to one side of a small (I assume) amplifier (little black box) and exit out the other side of the box via a cable with an XLR connector on it that feeds the building sound system. I'm wondering if it's possible to split this here. What parts / equipment would I need to make this interface with the webcast communicator?
Thanks,
Ken


We had a similar experience using the building sound feed of over driving the sound. We put a The ART TUBE MP STUDIO preamp. (eBay) Works great because we can control the volume feeding the webcasting SW by watching the vertical sound bar. We vary it by the speakers voice level. Simply took the mono building sound into a stereo to mono adapter and feed the stereo input in the capture card.

Keep it simple.
Arlan Beebe
Ann Arbor Stake

russellhltn
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Postby russellhltn » Tue Sep 11, 2012 5:37 pm

Mikerowaved wrote:Sometimes all that's needed is a simple audio mixer at the webcast site to be able to adjust the audio levels on-the-fly.


Which has the advantage of improving the sound for the broadcast. You're likely to find the building audio weak and "distant" when it come to organ and choir music. Fix two problems at once. Or at least future proof it.
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kwillisjr
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Update

Postby kwillisjr » Tue Sep 11, 2012 6:05 pm

I started the process tonight of trying to isolate the problem we experienced with our webcast this past Sunday. Here is what I found:

Ran the webcast communicator in the test mode and the only audio issue I had was some hum that I think is a ground loop (more on that in a minute). I tried to run a full webcast but could never view it on either of two computers (one was offsite) so I don't know yet whether or not the issue exists during a full webcast. I will be finding that out over the next few days.

I tracked the audio feeding the communicator back to a sound cabinet. It is fed from an Integrated Automixer. The brand is Ethernet and the model is live1026. It has banks of connectors on the back where 3 wire mic cables are being used to feed inputs and outputs. I believe the output of the mixer is line level. The individual conductors are stripped and inserted into a connector with screws that tighten onto the conductor. The connections are plus, minus, and ground. The output that feeds the communicator has another mic wire sharing the output. That wire goes into a conduit that feeds I don't know what. I don't think these mic wires are shielded but the do have drain wires that connect to ground. The mic wire that feeds the communicator enters the satellite cabinet and is spliced into a cheap RCA cable (they drop the drain wire at this point) that is inserted into one side of an RCA splitter / combiner (not a Y cable but performs the same function). The other side of the splitter / combiner has an RCA to RF adapter which connects to a coax cable which connects to an RF to Mini (1/8") adapter which plugs into the communicator. I'm thinking that at very least all of this mess needs to be eliminated and a mini plug soldered directly to the mic cable. I also think that re-attaching the drain wire might eliminate the hum mentioned earlier. Would there be any benefit in replacing the non-shielded mic cable with shielded mic cable?

Oh and one other thing. The audio level that is set in the communicator setup menu is set to one notch below the highest level.

russellhltn
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Postby russellhltn » Tue Sep 11, 2012 6:43 pm

kwillisjr wrote:I believe the output of the mixer is line level. The individual conductors are stripped and inserted into a connector with screws that tighten onto the conductor. The connections are plus, minus, and ground.


Yes, it probably is line level. The question is is it balanced or floating? Important distinction. Odds are that it's not unbalanced which is what we need.

kwillisjr wrote:The output that feeds the communicator has another mic wire sharing the output. That wire goes into a conduit that feeds I don't know what. I don't think these mic wires are shielded but the do have drain wires that connect to ground.


Another item sharing the output isn't a good sign. And if it had a drain wire, then it probably is shielded. Probably with foil which can be hard to see.

kwillisjr wrote:The mic wire that feeds the communicator enters the satellite cabinet and is spliced into a cheap RCA cable (they drop the drain wire at this point) that is inserted into one side of an RCA splitter / combiner (not a Y cable but performs the same function).


I'd like to know more about this.

kwillisjr wrote:The other side of the splitter / combiner has an RCA to RF adapter which connects to a coax cable which connects to an RF to Mini (1/8") adapter which plugs into the communicator.


The presence of the "RF" connector (I think you mean "F") is that it was originally designed to connect to a modulator that carries the chapel audio. I don't think you'd want to completely lose this feature.


kwillisjr wrote:I'm thinking that at very least all of this mess needs to be eliminated and a mini plug soldered directly to the mic cable.


Not so fast. My concern is that the signal coming out of the mixer is balanced. You can't just plug it into a unbalanced input without issues. A simple isolation transformer would be a good idea - if not a proper balanced to unbalanced adapter. Otherwise you're grounding out half your signal.

kwillisjr wrote:I also think that re-attaching the drain wire might eliminate the hum mentioned earlier.


One of the advantages of balanced is that you don't have to connect the ground wire. That may be desirable in certain situations. Otherwise you may find yourself tying the 3rd pin power ground together through your audio cabling. I think you need to do a proper bal to unbal and see how that works.
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KeithWilson
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Postby KeithWilson » Tue Sep 11, 2012 8:19 pm

You can modify the audio volume in the webcast communicator audio settings. I know the church is now recommending a https://tech.lds.org/wiki/Availability_of_Meetinghouse_Webcast_Products_and_Components audio mixer, a couple are listed on this link. We had the same problem with our first webcast. I advise testing the webcast again with the communicator audio volume turned down significantly.

kwillisjr
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Balanced or unbalanced?

Postby kwillisjr » Tue Sep 11, 2012 8:42 pm

I'm thinking this is probably a blanced output. I see that the church online store has an adapter just for adapting from XLR to 1/8". According to the store website, this should have been included with the communicator. Who knows where that might be now. I'm going to see if I can find any information online for this mixer.


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