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Author Topic: Ambiental music
Ariel Vocal
Film Handler

Posts: 20
From: Cochabamba, Cochabamba / Bolivia
Registered: Apr 2012


 - posted 07-05-2015 05:45 PM      Profile for Ariel Vocal     Send New Private Message       Edit/Delete Post 
hello
I recently bought a small amplifier of those used for karaoke, I made a wiring from one point to several rooms to distribute music abmbiental through the amplifier, in these rooms have installed both processors 650 and 750 cp.
at first everything it worked ok, but recently, we noticed that the background music is filtered during the show, for some channels a distorted version of the music that is playing while it is projecting the movie, in another room you hear them noise listening to rhythm of the music being played on the amplifier.

A may be due this ?, the signal is coming with very impedance, or is a grounding problem?

Thanks for your help, greetings!

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Justin Hamaker
Film God

Posts: 2253
From: Lakeport, CA USA
Registered: Jan 2004


 - posted 07-05-2015 08:47 PM      Profile for Justin Hamaker   Author's Homepage   Email Justin Hamaker   Send New Private Message       Edit/Delete Post 
This seems like an obvious question, but do you have the music going through the non-sync channel of you processors?

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Ariel Vocal
Film Handler

Posts: 20
From: Cochabamba, Cochabamba / Bolivia
Registered: Apr 2012


 - posted 07-05-2015 09:54 PM      Profile for Ariel Vocal     Send New Private Message       Edit/Delete Post 
Yes Justin, sorry for not saying in the question.

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 07-06-2015 07:13 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
Ariel, your system to distribute the music is probably completely screwed up. You can't simply wire an amplifier's output in analog to multiple booths and expect this to run clean. You have to learn something about proper analog audio distribution.

- Carsten

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Harold Hallikainen
Jedi Master Film Handler

Posts: 906
From: Denver, CO, USA
Registered: Aug 2009


 - posted 07-06-2015 10:02 AM      Profile for Harold Hallikainen   Author's Homepage   Email Harold Hallikainen   Send New Private Message       Edit/Delete Post 
I'm going to guess that the issue is with driving an unbalanced input with audio that MAY be putting voltage on the shield with respect to ground. An audio transformer in front of each processor input might solve the problem.

Harold

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 07-06-2015 10:21 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Ultra Stereo makes a nice music distribution amplifier that can provide isolated outputs to each screen. Also there should be many used Smart ones out there
Component Engineering makes one that is daisy chained and I find it not as nice as I would have liked

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 07-06-2015 11:56 AM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
Aside from all the aforementioned, the level may be so high it develops a slight voltage on the backplane which leaks into everything else. Seen it before.

You may need to use a resistive voltage divider at the processor end such that you have no more than 300 mVolts hitting the non sync input. Just a guess.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 07-06-2015 04:10 PM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
Well yeah, if I read "karaoke amplifier" hooked up to the non-sync input of a sound processor, equal alarm bells go off.

What amplifier output exactly did you hook up onto those non-sync inputs? And how did you hook it up? Did you run a dedicated pair of wires per room or did you daisy chain it? And did you did hook it up in parallel I suppose?

quote: Gordon McLeod
Component Engineering makes one that is daisy chained and I find it not as nice as I would have liked
Daisy chaining analog audio just feels wrong. I guess you want a dedicated output per "subscriber" which you can also regulate per output, not just because you can avoid one device screwing it up for all others, but also because every device in the chain will experience a considerable drop in signal strength, because of the increasing distance to the source.

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 07-06-2015 07:23 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
The CE device worked pretty well on account of matching transformers on the receiving end. Kind of like 70 Volt lines where each speaker had a transformer with taps riveted to the speaker frame so it can only take so much of the power.

Old fashioned but it worked without have to use home runs.

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