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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Wed Oct 21, 2009 11:03 am Post subject: Eliminate Pop Sound when playback with ISD2560 |
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hello,
is there any workaround on how to eliminate pop sound when doing playback voice of ISD2560? |
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mattcro
Joined: 03 Oct 2007 Posts: 327 Location: Scotland
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Posted: Wed Oct 21, 2009 6:09 pm Post subject: |
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Are you using a single-ended output from the chipcorder, eg into an opamp? If so, you might be getting the pop/thump from the output DC offset. During playback, the outputs are biased to 2.5V but during powerdown/standby the outputs are at 0V. You probably need to use a differential input to the op-amp (standard differential amplifier circuit). You can also try preventing powerdown between messages/words by keeping PD low.
If you are getting a pop and using a speaker connected directly to the SP+/- outputs, you might be recording the pop due to poor supply decoupling or input DC offsets - use capacitor coupling for the analog input.
Also make sure you aren't recording the noise from a button (eg stop button) at the end of each message/word/phrase. _________________ If all else fails, read the manual. Even better: read the manual before something fails. If you can't find it in the manual, search the forum.
BascomAVR 2.0.8.5 |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Thu Oct 22, 2009 1:32 am Post subject: |
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my schematic is like below attached. i think is in differential mode
as for the PD low, i need message cueing mode, so need to reset the addr pointer back to 0 before fast forward. kindly review the schematic |
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mattcro
Joined: 03 Oct 2007 Posts: 327 Location: Scotland
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Posted: Thu Oct 22, 2009 5:30 pm Post subject: |
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Your circuit looks OK to me. The differential input to the LM386 should reduce the pop a lot, but maybe the LM386 does not have very good common-mode rejection so there is still a small pop. Do you still get the pop if you have the speaker connected directly to the ISD2560 and disconnect the LM386?
Do you get the pop at the start of a message or at the end?
I don't know much about the ISD devices - it's a long time since I used one of these and it was used with the speaker connected directly to the chipcorder, not an external amp. _________________ If all else fails, read the manual. Even better: read the manual before something fails. If you can't find it in the manual, search the forum.
BascomAVR 2.0.8.5 |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Thu Oct 22, 2009 11:43 pm Post subject: |
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i'm gonna test it like that,directly to SP+ SP- pin using speaker
and see what came up
the pop sound is in the end of every message i played |
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AdrianJ
Joined: 16 Jan 2006 Posts: 2483 Location: Queensland
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Posted: Tue Oct 27, 2009 4:18 am Post subject: |
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I also used earlier versions of the ISD chips a long time ago, and they produced unacceptable clicks at the end of messages. Never solved the problem. Now I use AVR to generate speech direct from either Atmel Dataflash or Ramtron Fram memory, and it works well. You still some care over how you start and end messages, but at least it is directly under your control, unlike with the ISD chips. _________________ Adrian Jansen
Computer language is a framework for creativity |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Tue Oct 27, 2009 4:49 am Post subject: |
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well, been solve it
i forgot to comment out my print statement debugging
now the pop is very low |
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mattcro
Joined: 03 Oct 2007 Posts: 327 Location: Scotland
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Posted: Tue Oct 27, 2009 11:19 am Post subject: |
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Good to hear you have solved/reduced the problem. I guess you now have a very short pulse on the PD pin to reset the address, so the pop is less noticeable? That's probably as good as you will get, going by Adrian's comments... _________________ If all else fails, read the manual. Even better: read the manual before something fails. If you can't find it in the manual, search the forum.
BascomAVR 2.0.8.5 |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Tue Oct 27, 2009 11:41 pm Post subject: |
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yes, the pop sound now is less noticable |
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pinkfloyd11
Joined: 02 Jul 2007 Posts: 247
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Posted: Tue Mar 05, 2013 3:20 pm Post subject: |
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Hello
could you share part of your code that drive ISD2560?
Thanks |
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