Audio System Line out has distortion/clipping

Discussions around meetinghouse sound systems, microphones, assisted listening devices, and translation equipment
EarloftheWest
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Audio System Line out has distortion/clipping

Postby EarloftheWest » Mon Aug 31, 2020 9:42 am

Hi, everyone.
Our region has been instructed to have a chapel meeting broadcast every Sunday.
Yesterday was our first broadcast from the chapel.
It went fine for a first time but there were a few issues with the audio.
Here's my setup...
I found the mono output under the Sacrament table that had been used to record to the tape recorder that's still there.
I plugged in a mono to stereo adapter and then ran a 3.5 mm stereo male to male cable into the audio input of my capture card.
We used Zoom Webinar to broadcast the meeting.
Attendees said the audio had an issue. I logged in on my phone to listen in and indeed heard there was an issue with the audio.
I wouldn't say that it sounded distorted. The best way for me to attempt to describe it is that I believe the audio was clipping because I'm guessing that the volume output from the sound system was too loud.
When we looked at the Zoom settings it had the audio adjusted all the way down.
After the meeting was over we did some testing via Zoom to see if we could get better sound.
I plugged in my Takstar shotgun mic to the capture card.
Sound was clear and the Zoom audio levels were in the middle.
My preference is to come directly off the chapel audio system because that looks cleaner at the podium than having another mic there and it's simpler to setup.
So I'd like to try and get the sound off of the chapel audio system to work with my broadcast.
I'm guessing here but I wonder if I purchase an attenuator to reduce the volume from the sound system would be the solution?

As an aside...
For years, when our Stake broadcasts Stake Conference to the chapels from the Stake Center, I noticed an issue with the sound. It had this same problem.

Thanks, everyone!
I hope you're all doing well.
Let me know if you have any questions.

russellhltn
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Re: Audio System Line out has distortion/clipping

Postby russellhltn » Mon Aug 31, 2020 10:27 am

EarloftheWest wrote:I'm guessing here but I wonder if I purchase an attenuator to reduce the volume from the sound system would be the solution?

Yes, you need an attenuator. The sound system is line out, and it sounds like you're connecting it to a mic in.
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EarloftheWest
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Re: Audio System Line out has distortion/clipping

Postby EarloftheWest » Mon Aug 31, 2020 11:21 am

russellhltn wrote:
EarloftheWest wrote:I'm guessing here but I wonder if I purchase an attenuator to reduce the volume from the sound system would be the solution?

Yes, you need an attenuator. The sound system is line out, and it sounds like you're connecting it to a mic in.

Glad to see I'm on the right track.
Would something like this work?
https://www.amazon.com/Volbox-inline-au ... 220&sr=8-3
Or do I need this:
https://www.amazon.com/Sescom-LN2MIC-ZO ... 516&sr=8-9

Thanks!

russellhltn
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Re: Audio System Line out has distortion/clipping

Postby russellhltn » Mon Aug 31, 2020 1:32 pm

The volume control may work. It depends on it's "taper" as to how fast it gets loud at the low end.

The cable will probably work as long as HDSLR have the same mic connections as a computer. I'm not sure about that.

Keep in mind the sound system audio out is strictly mono (tip and sleeve) There is no "ring". A stereo connection would work, but be only one channel. I don't think that's a concern for either of these options.
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EarloftheWest
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Re: Audio System Line out has distortion/clipping

Postby EarloftheWest » Mon Aug 31, 2020 3:21 pm

russellhltn wrote:The volume control may work. It depends on it's "taper" as to how fast it gets loud at the low end.

The cable will probably work as long as HDSLR have the same mic connections as a computer. I'm not sure about that.

Keep in mind the sound system audio out is strictly mono (tip and sleeve) There is no "ring". A stereo connection would work, but be only one channel. I don't think that's a concern for either of these options.

Thanks for your help on this.

Switching gears on solving this problem...
Our Chapel has wireless earphones that people who are hard of hearing can borrow from the library and listen to the speakers.
Would there be any benefit/ease of use in receiving the signal wirelessly from our sound system and put into the mic input?

russellhltn
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Re: Audio System Line out has distortion/clipping

Postby russellhltn » Mon Aug 31, 2020 4:20 pm

EarloftheWest wrote:Would there be any benefit/ease of use in receiving the signal wirelessly from our sound system and put into the mic input?


First, you need to make sure the transmitter is reliable. I've had some become intermittent. The next issue is you have to make sure the receiver will turn on and stay on. I think most do not have a switch, but rely on the presence of the earphone to turn on. I'm not sure about the details. It may not be the presence of a plug, but the low impedance of the earphone that turns it on. You'd have to play with it to make sure it works and will stay on.

Older Comtek units can be noisy.

While it can be done, it seems like more opportunity for things to go wrong. I'm not sure if it overcomes the advantage of not having to run a wire.
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EarloftheWest
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Re: Audio System Line out has distortion/clipping

Postby EarloftheWest » Mon Aug 31, 2020 7:34 pm

@russellhltn
Another question about attenuation cables...
Sescom seems to be one of the leaders in making attenuation cables.
It appears that they make a variety of 3.5mm line out to mic in cables with differing attenuation levels.

From their website...
https://www.sescom.com/products/view/ca ... der-cables
I'm seeing 50db, 35db, 33db and 25db.

Based on research, our ward has purchased the Canon HF R800.
This camcorder, in addition to our capture card, requires a powered microphone. i.e., one with a battery etc.

Is there anyway that we can get guidance on the exact cable that we need?
Or would a 25db be sufficient in most cases?

Thanks!

EarloftheWest
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Posts: 70
Joined: Wed Jan 26, 2011 11:55 am

Re: Audio System Line out has distortion/clipping

Postby EarloftheWest » Tue Sep 01, 2020 7:19 am

UPDATE:
I sent Sescom an email and they suggested that this cable:
LN2MIC-ZOOMH4N 3.5mm Line To Mic DSL Cable For Zoom H4-PRO Recorders – 9 Inch
which provides 25db of attenuation should be the one I should purchase.

russellhltn
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Re: Audio System Line out has distortion/clipping

Postby russellhltn » Tue Sep 01, 2020 10:42 am

I haven't had a chance to run the numbers, but it has to be in the right ballpark in order to meet that usage case.

One issue - these are all stereo connections. Depending on what controls you have, you may need to add a mono to stereo adapter in order to adapt the mono sound system output to the stereo connection the cable/camera is expecting.
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drepouille
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Re: Audio System Line out has distortion/clipping

Postby drepouille » Tue Sep 01, 2020 1:55 pm

OK, so the "Record Out" jack is a mono jack, with just a tip for mono audio and a sleeve for ground, right?
A TRS connector uses the tip for the left channel, the ring for the right channel, and the sleeve for ground.
A TRRS connector (used by phones, laptops, and cameras) uses the tip for the left channel, the first ring for the right channel, the second ring for ground, and the sleeve for the microphone.

So we need a cable (or a cable and an adapter) that will connect the mono audio contact (the tip) of the "Record Out" TS jack to the microphone contact (the sleeve) of our laptop or camera TRRS jack, and attenuate the line level signal so it doesn't overpower the microphone input.
Dana Repouille, Plattsmouth, Nebraska


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