Re: Audio path gain, was: Re: Bluetooth module
Did you really meant bass fix? http://wiki.openmoko.org/wiki/GTA02_bass_fix Or buzz fix: http://wiki.openmoko.org/wiki/Buzz_Fix ? 2011/2/6 Hrabosh zbyne...@volny.cz: I was doing bass-fix to my Freerunner today so I did the the same measurement with generator again. I run Voice notes and set the generator so that the amplitude was simmilar to the amplitude of voice, captured by the microphone. LAter on I was listening to the files recorded when setting the generator and the 1kHz beep was clean and the volume was OK. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Audio path gain, was: Re: Bluetooth module
Yes, I really meant bass fix. I have replaced each 1uF cap with 2x 47uF caps in parallel. They are isolated by heat-shrinking tube and everything even fit under the metal cover. It really helped a lot, no problem using my FR as portable player now. I have taken some pictures ... anyone interested? I may put them online if so. BTW... although my phone seems not to be affected by GSM buzz problems, I did buzz fix also just for shure. Zb. Martix píše v Po 07. 02. 2011 v 16:31 +0100: Did you really meant bass fix? http://wiki.openmoko.org/wiki/GTA02_bass_fix Or buzz fix: http://wiki.openmoko.org/wiki/Buzz_Fix ? 2011/2/6 Hrabosh zbyne...@volny.cz: I was doing bass-fix to my Freerunner today so I did the the same measurement with generator again. I run Voice notes and set the generator so that the amplitude was simmilar to the amplitude of voice, captured by the microphone. LAter on I was listening to the files recorded when setting the generator and the 1kHz beep was clean and the volume was OK. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Audio path gain, was: Re: Bluetooth module
Al Johnson píše v Pá 04. 02. 2011 v 13:46 +: How did you pick 0.5mV as a suitable input amplitude? Measurement of peaks when talking? It was completely wrong! I did some internet search and found that micropohone like that in FR usually produce signal with amplitude in tens of mV. I was wondering if the singal was only 0.5mV it wouldn't probalby get distorted so easily - so I went to check my generator and saw that the attenuator was set incorrectly and so the signal was probably way higher than 0.5mV. I was doing bass-fix to my Freerunner today so I did the the same measurement with generator again. I run Voice notes and set the generator so that the amplitude was simmilar to the amplitude of voice, captured by the microphone. LAter on I was listening to the files recorded when setting the generator and the 1kHz beep was clean and the volume was OK. I rewrite the text and put there all pictures from the scope I made. http://hnet.endofinternet.net/elektro/Freerunner/ALSA/sound_setting.html Seems that the sidetone may be set to 2 instead of 1, but mic should stay 0. Thanks for your question ! Zb. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Audio path gain, was: Re: Bluetooth module
On Sunday 23 January 2011, Hrabosh wrote: Al Johnson píše v Pá 21. 01. 2011 v 10:34 +: On Friday 21 January 2011, Hrabosh wrote: Hi guys, yesterday I opened my freerunner to check whether mine FR is affected by R3004 issue [1]. It was, I put a piece of wire there instead of those two caps and volume got better! I have also connected sine wave from generator to the WD8753 mic input and cheched it on the WD8753's output with the oscilloscope. It seemes that the audio codec chip gets into trouble (distortion, oscillations) if the overall audio path has higher gain than 1. I'm going to write more about this soon, with the scope pictures included (taken by my camera, I don't have DSO at home :-/ ) That would be interesting to see, but your summary seems wrong or perhaps oversimplified. Distortion is inevitable if you overload an amp, and oscillation isn't unusual immediately after overload. It isn't a function of the overall path gain though. The wolfson has a chain of amps and volume controls, and it only needs overload at one of them to introduce distortion. Stick the gain too high on the first stage (mic input) and the distortion won't go away no matter how far you turn down the gain on later stages. This has been a long standing problem with the default volume settings. Yes, it is oversimplified. It is obvious that you can't fix distortion by lowering the gain of next-in-chain amplifier. You are just controlling the volume of already distorted signal. If it was that obvious we wouldn't have had default settings guaranteed to cause distortion earlier than necessary in the first place. It seems it's only obvious to those of us with a grounding in analogue electronics, or those who spend time with guitar amps and similar. I put that picture from my scope with a short description to my web page, here: http://hnet.endofinternet.net/elektro/Freerunner/ALSA/sound_setting.html I was very surprised how LOW I had to set the audio controls to get rid of distortion: Mic2: 0 Sidetone: 1 Strange ... How did you pick 0.5mV as a suitable input amplitude? Measurement of peaks when talking? ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Audio path gain, was: Re: Bluetooth module
Al Johnson píše v Pá 21. 01. 2011 v 10:34 +: On Friday 21 January 2011, Hrabosh wrote: Hi guys, yesterday I opened my freerunner to check whether mine FR is affected by R3004 issue [1]. It was, I put a piece of wire there instead of those two caps and volume got better! I have also connected sine wave from generator to the WD8753 mic input and cheched it on the WD8753's output with the oscilloscope. It seemes that the audio codec chip gets into trouble (distortion, oscillations) if the overall audio path has higher gain than 1. I'm going to write more about this soon, with the scope pictures included (taken by my camera, I don't have DSO at home :-/ ) That would be interesting to see, but your summary seems wrong or perhaps oversimplified. Distortion is inevitable if you overload an amp, and oscillation isn't unusual immediately after overload. It isn't a function of the overall path gain though. The wolfson has a chain of amps and volume controls, and it only needs overload at one of them to introduce distortion. Stick the gain too high on the first stage (mic input) and the distortion won't go away no matter how far you turn down the gain on later stages. This has been a long standing problem with the default volume settings. Yes, it is oversimplified. It is obvious that you can't fix distortion by lowering the gain of next-in-chain amplifier. You are just controlling the volume of already distorted signal. I put that picture from my scope with a short description to my web page, here: http://hnet.endofinternet.net/elektro/Freerunner/ALSA/sound_setting.html I was very surprised how LOW I had to set the audio controls to get rid of distortion: Mic2: 0 Sidetone: 1 Strange ... But ... when I was dismounting the phone, I dammaged the bluetooth module. The module itself may be OK, but the flex cable is torn off. Don't you have any idea where can I buy some spare? I've not seen anyone list them as a spare for sale, but any of the distributors might have them available. Nicholas from Golden Delicious answered my desperate E-mail :-) ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
