Building a cable from sound system to "mic in"

Discussions around meetinghouse sound systems, microphones, assisted listening devices, and translation equipment
mrbitsch
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Re: Building a cable from sound system to "mic in"

Postby mrbitsch » Thu Sep 17, 2020 12:32 pm

davidanderspatten wrote:Have you considered using an ALS (Assisted Listening System) receiver to get sound? The receiver has a volume control so you can turn it down. You may be able to do that and get by without an attenuator.


I've used the ALS receiver in the past to get sound for various things (the sacrament broadcast for one of our buildings because the Record Out jack was broken, so we were using the ALS receiver while the FM group fixed that).

Some factors to keep in mind with the ALS system:
1) The receivers are battery operated, and typically only get 40 hours of battery life. (which means you'll have to remember to turn it off each week, or you'll have a dead battery the next week)
2) The ALS system is typically a narrow-band FM broadcast system, you lose a bit of sound quality because of the lower-bandwidth.
3) It's an RF system so it's susceptible to interference. (I've yet to listen to an ALS system that didn't have some kind of extraneous noise on it, and as russellhltn mentioned the missmatch between the headphone out on the ALS and the input on your broadcast device will likely mean needing to amplify the signal, which likely amplifies the noise. In our case when we were temporarily using the ALS system we had this noticeable background hum on the audio.)

russellhltn
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Re: Building a cable from sound system to "mic in"

Postby russellhltn » Thu Sep 17, 2020 1:38 pm

Some things to keep in mind with the ALS:

The older COMTEK units needs to see 100 ohms or less to turn on/stay on. Odds are, a common cable setup isn't going to do that.

The newer Listen TECH. units are shipped with the "Jack Sense" turned off, so that should work. But if "Jack Sense" has been turned on, it will need to see 32 ohms or it will turn off in 60 seconds.

I see one suggestion is to use a "Y" cable to connect a an earphone. That will work, but I'd be concerned the earphone will also act as a microphone and add noise and/or color the sound. At least that was my experience in the old days trying to record while tapping off of a speaker.

Bottom line, test and verify your plan. Don't assume it will work.
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drepouille
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Re: Building a cable from sound system to "mic in"

Postby drepouille » Thu Sep 17, 2020 1:41 pm

That makes perfect sense. I tested the Comtek receiver twice with dismal results at both high and low volume. I am going to try to tape a Lavalier mic to the podium mic boom this Sunday to see how the quality of that sound comes through.
Dana Repouille, Plattsmouth, Nebraska

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Re: Building a cable from sound system to "mic in"

Postby Mikerowaved » Sat Sep 19, 2020 2:16 am

russellhltn wrote:But this looks promising. Just need to add a 3.5mm to 3.5mm 25' cable and you should be good to go.

Just ordered a pair of the above adapters, along with a pair of 25' shielded cables. Didn't see any other adapter/attenuators that would work. These are the full URL's for my order:
https://www.amazon.com/gp/product/B00OAW85ZG 3.5mm TRRS to TRS adapter with line-level to mic-level attenuator.
https://www.amazon.com/gp/product/B07G56Z531 3.5mm TRS male-male 25' shielded cable.

I also ordered this car cellphone mount to attach near one of the pulpit corners furthest from the speaker. I plan on setting the flexible tubing to near vertical to start, with further adjustments to be made once it arrives. The goal is to position the phone at, or slightly above eye level; similar to the view you'd get from a wall-mounted camera in the back of the chapel. Might even be close enough for direct audio, but I'm not counting on that. It will ride up and down with the pulpit for different speaker heights. My ultimate goal is to set-and-forget, until it's time to shut down the webcast.
https://www.amazon.com/gp/product/B07W5GYK5G

With shipping (on the 1st item) and UT tax, the total came to $50.45 per building. If this is our only tech expenses, I'd be very happy with that.
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drepouille
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Re: Building a cable from sound system to "mic in"

Postby drepouille » Sat Sep 19, 2020 6:01 am

I bought a 25 inch Flexible Arm 360 Desk or Bed Gooseneck Mount Stand for Cell Phone 11 Pro XS Max XR X 8 7 6 Plus and Logitech C925e, C922x, C930e,C922,C930,C920,C615,Brio
https://www.amazon.com/gp/product/B088RC8N6B
Dana Repouille, Plattsmouth, Nebraska

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Re: Building a cable from sound system to "mic in"

Postby CalS201 » Wed Sep 23, 2020 12:08 pm

This product does what you want. It attenuates line level to mic level, presents the proper impedance to the laptop/iOS device, and outputs to a TRRS. https://www.amazon.com/dp/B078HGFS3Z

EarloftheWest
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Re: Building a cable from sound system to "mic in"

Postby EarloftheWest » Fri Sep 25, 2020 4:40 pm

Since the REC OUT jack is mono, would a mono to stereo adapter be needed for either of the above solutions?

russellhltn
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Re: Building a cable from sound system to "mic in"

Postby russellhltn » Fri Sep 25, 2020 4:46 pm

EarloftheWest wrote:Since the REC OUT jack is mono, would a mono to stereo adapter be needed for either of the above solutions?

It depends on what it's feeding. In most cases, it would be an attenuator and it would depend on how it's wired.
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idjeeper2
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Re: Building a cable from sound system to "mic in"

Postby idjeeper2 » Wed Sep 30, 2020 2:25 pm

russellhltn wrote:Rather than tack onto an already lengthy thread, I thought I'd start a new one. This past week I built my own cable and was able to successfully use it this past Sunday for a webcast using a cell phone. There might be a pre-made cable out there that can do that, but it's not easy to find and I'd have to order it.


I am far from a technology guy, but this sounds close to what I need. In my case, I need to go from the "Record Out" to the "Mic In" on my laptop. My understanding is that I'm going from a line level TS connector to a mic level TRS connector. Does that sound correct?

So, my questions are:

Is the L-pad using the resistors you described still appropriate?

Are 1/4 watt resistors appropriate, not enough, or overkill?

My understanding is that the connections are tip to tip and sleeve to sleeve, with the ring unconnected. Is that correct?

Anything else I need to be considering?

I apologize for the basic nature of my questions. I'm kind of learning as I go.

Many thanks

russellhltn
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Re: Building a cable from sound system to "mic in"

Postby russellhltn » Wed Sep 30, 2020 2:35 pm

idjeeper2 wrote:My understanding is that I'm going from a line level TS connector to a mic level TRS connector. Does that sound correct?

That depends on the laptop. Is the icon by the plug of a microphone, or a headset(headphone with boom mic)?

TRS is correct for "mic", TRRS is needed for "headset".

idjeeper2 wrote:Is the L-pad using the resistors you described still appropriate?

I need to do a little more research to make sure it's not overkill, but they do work.

idjeeper2 wrote:Are 1/4 watt resistors appropriate, not enough, or overkill?

They're what's handy. I'd even consider 1/8th watt if I'm trying to build this into the plug. However, my local electronics store only goes down to 1/4 watt.

idjeeper2 wrote:My understanding is that the connections are tip to tip and sleeve to sleeve, with the ring unconnected. Is that correct?

That's correct - assuming you're using a "mic in" and not "headset". Of course, the tips pass though a resistor.

idjeeper2 wrote:Anything else I need to be considering?

Just your skill as a maker. Since you're considering building this, I assume you feel confident about the construction part. The absence of that skill seems to be driving most to ordering from Amazon.
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