Start up an shutdown audio

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  • Question
  • Updated 6 months ago
Why the pop in audio when starting up and shutting down my 6600M ?
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FRED W9TB

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Posted 6 months ago

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Robert Lonn

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Flex tells me that this is Normal behavior, but they should be able to fix this with a Software revision... However I have not heard anything from anyone here on the forum or from Flex about the pop in the audio when shutting down... I have Not heard it when starting up the radio...
(Edited)
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Al / NN4ZZ

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Hi Fred,
I asked about this 3 years ago on my 6700.  Here is the question and Gerald's reply.  Probably the same for the new models.

https://community.flexradio.com/flexradio/topics/audio-pop-when-starting-up-and-shutting-down-the-ra...

Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 & SSDR-W  V 2.2.8
Win10
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Robert Lonn

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BUT!!!! Every other radio I own, all 12 of them, do not suffer from this problem,, I admit they are radios with built in speakers, not a low level audio preamp output, but after 3 years you would still think this is something they could have engineered OUT of the power down sequence.. ???

Robert
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Bill -VA3WTB

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It really is not a problem. But what some are doing is turning the speaker audio much higher in SSDR and turn the outboard speaker down, you should notice this pop very weak.
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Al / NN4ZZ

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Hi Bill,
I tried that back when I reported the issue 3 years ago, it wasn’t a viable solution for me. I ended up back with the SSDR and speaker volume settings that worked best while operating.

Agree it is pretty minor, more of a fit and finish thing. Here is the analogy I made back then:

If you had a Rolls Royce and every time you opened and closed the door to get in or out it squeaked, would you care?

Regards, Al / NN4ZZ
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Robert Lonn

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That can work but a lot depends on the outboard speaker device being used,, My HK speakers are well engineered and do match up well... I picked up some AR speaker-amplifiers the other day, and may try them this weekend.. These Vintage speakers sound just awesome from my preliminary testing.. ..

I have several options on how I listen to the 6600M audio... I am expecting a Audio HDMI Inserter from Amazon to insert the audio into the HDMI stream so I can hear the audio on my 50" LG 4K TV Set...  Many variables here on how the audio levels are set both in the radio and externally...

Also, the Audio Frequency Curve can change with the setting of the level.. This depends on the design of the audio circuit... I feel the Flex curve is very good, as even at low audio levels the fidelity is quite good...  Robert

(Edited)
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David-N5PSM

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Most integrated audio drivers have a capacitor to isolate the DC from the output. In that way the output of the driver can sit at 1/2 of VCC so that it can swing negative and positive.  The "POP" is the driver shutting down and the capacitor being discharged.  In order to eliminate it  you could bias the load side also to 1/2 of Vcc,,,   however that has it's own nest of problems.  ....Tim, am I right?
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Steven Linley

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I notice it with all newer radios.