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[Q]Audio processing technique to increase speech quality?

Started by October 16, 2007
Hi,

I am in a process to improve the speech quality out of our current
speech codec. Basically, our speech codec is an ADPCM codec with bunch
of interpolation and decimation filters and Sigma-Delta ADDA, and we
have already adjusted all the filters so now it works just fine.
However, we are still not 100% satisfied with the audio quality, we
want to make the sound more clear so we are thinking of using some
audio processing methods (beyond filter coefficients adjustment but
not going to too complex method such like noise reduction ) to achieve
that. I am thinking of using such like Equalizer, Dithering, Echo,
Flager.... to try to make the speech better. So my question is what
are the common ways to achieve that or I am just expecting too much?
Thanks

On Oct 16, 9:54 pm, heliboy2...@yahoo.com.tw wrote:
> > I am in a process to improve the speech quality out of our current > speech codec. Basically, our speech codec is an ADPCM codec with bunch > of interpolation and decimation filters and Sigma-Delta ADDA, and we > have already adjusted all the filters so now it works just fine. > However, we are still not 100% satisfied with the audio quality, we > want to make the sound more clear so we are thinking of using some > audio processing methods (beyond filter coefficients adjustment but > not going to too complex method such like noise reduction ) to achieve > that. I am thinking of using such like Equalizer, Dithering, Echo, > Flager.... to try to make the speech better.
why would and Echo or Flanger (i presume that's what you meant) make the speech quality better? it might make it fun or interesting to listen to, but why would you consider this for a codec? it won't make the speech clearer. whether Equalizing (which is another term for Filtering) or Dithering will help is a question that can only be answered in the context of your specific architecture and application. r b-j
On Oct 17, 6:54 am, heliboy2...@yahoo.com.tw wrote:
> Hi, > > I am in a process to improve the speech quality out of our current > speech codec. Basically, our speech codec is an ADPCM codec with bunch > of interpolation and decimation filters and Sigma-Delta ADDA, and we > have already adjusted all the filters so now it works just fine. > However, we are still not 100% satisfied with the audio quality, we > want to make the sound more clear so we are thinking of using some > audio processing methods (beyond filter coefficients adjustment but > not going to too complex method such like noise reduction ) to achieve > that. I am thinking of using such like Equalizer, Dithering, Echo, > Flager.... to try to make the speech better. So my question is what > are the common ways to achieve that or I am just expecting too much? > Thanks
How about pitch enhancement
> > How about pitch enhancement
Great suggestion, it may just a littlt too complex for our purpose, but still good thing to try. Thanks
On 10 17 ,   10 43 , robert bristow-johnson
<r...@audioimagination.com> wrote:
> On Oct 16, 9:54 pm, heliboy2...@yahoo.com.tw wrote: > > > > > I am in a process to improve the speech quality out of our current > > speech codec. Basically, our speech codec is an ADPCM codec with bunch > > of interpolation and decimation filters and Sigma-Delta ADDA, and we > > have already adjusted all the filters so now it works just fine. > > However, we are still not 100% satisfied with the audio quality, we > > want to make the sound more clear so we are thinking of using some > > audio processing methods (beyond filter coefficients adjustment but > > not going to too complex method such like noise reduction ) to achieve > > that. I am thinking of using such like Equalizer, Dithering, Echo, > > Flager.... to try to make the speech better. > > why would and Echo or Flanger (i presume that's what you meant) make > the speech quality better? it might make it fun or interesting to > listen to, but why would you consider this for a codec? it won't make > the speech clearer. whether Equalizing (which is another term for > Filtering) or Dithering will help is a question that can only be > answered in the context of your specific architecture and application. > > r b-j
Yeah I am not sure if Echo, Flager will help, but I am in a situation that I will try anything. Thanks
hurry wrote:
> On Oct 17, 6:54 am, heliboy2...@yahoo.com.tw wrote: >> Hi, >> >> I am in a process to improve the speech quality out of our current >> speech codec. Basically, our speech codec is an ADPCM codec with bunch >> of interpolation and decimation filters and Sigma-Delta ADDA, and we >> have already adjusted all the filters so now it works just fine. >> However, we are still not 100% satisfied with the audio quality, we >> want to make the sound more clear so we are thinking of using some >> audio processing methods (beyond filter coefficients adjustment but >> not going to too complex method such like noise reduction ) to achieve >> that. I am thinking of using such like Equalizer, Dithering, Echo, >> Flager.... to try to make the speech better. So my question is what >> are the common ways to achieve that or I am just expecting too much? >> Thanks > > How about pitch enhancement
"Enhance" means "heighten" or "intensify", but many people misuse it to mean "enlarge", "augment", or "improve". What does "pitch enhancement" mean to you? Posting that would help get you an answer. Jerry -- Engineering is the art of making what you want from things you can get. &macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
On Oct 17, 12:10 am, heliboy2...@yahoo.com.tw wrote:
> On 10 17 , 10 43 , robert bristow-johnson > > > > <r...@audioimagination.com> wrote: > > On Oct 16, 9:54 pm, heliboy2...@yahoo.com.tw wrote: > > > > I am in a process to improve the speech quality out of our current > > > speech codec. Basically, our speech codec is an ADPCM codec with bunch > > > of interpolation and decimation filters and Sigma-Delta ADDA, and we > > > have already adjusted all the filters so now it works just fine. > > > However, we are still not 100% satisfied with the audio quality, we > > > want to make the sound more clear so we are thinking of using some > > > audio processing methods (beyond filter coefficients adjustment but > > > not going to too complex method such like noise reduction ) to achieve > > > that. I am thinking of using such like Equalizer, Dithering, Echo, > > > Flager.... to try to make the speech better. > > > why would and Echo or Flanger (i presume that's what you meant) make > > the speech quality better? it might make it fun or interesting to > > listen to, but why would you consider this for a codec? it won't make > > the speech clearer. whether Equalizing (which is another term for > > Filtering) or Dithering will help is a question that can only be > > answered in the context of your specific architecture and application. > > Yeah I am not sure if Echo, Flager will help, but I am in a situation > that I will try anything.
"try anything"? for what end??? what do you mean by "improve the speech quality". i know what "speech" is. what do you mean by either "improve" or "quality"? i have absolutely know fucking idea what you're talking about with respect to a "codec". maybe you should define that also; i used to think i knew what the term "codec" meant, now i am not sure. r b-j
> > How about pitch enhancement
Great suggestion, thanks
heliboy2003@yahoo.com.tw wrote:

> Hi, > > I am in a process to improve the speech quality out of our current > speech codec. Basically, our speech codec is an ADPCM codec with bunch > of interpolation and decimation filters and Sigma-Delta ADDA, and we > have already adjusted all the filters so now it works just fine. > However, we are still not 100% satisfied with the audio quality, we > want to make the sound more clear so we are thinking of using some > audio processing methods (beyond filter coefficients adjustment but > not going to too complex method such like noise reduction ) to achieve > that. I am thinking of using such like Equalizer, Dithering, Echo, > Flager.... to try to make the speech better. So my question is what > are the common ways to achieve that or I am just expecting too much? > Thanks >
I noticed that you asked the same question in comp.speech.research. In neither did you explicitly state that that the codec was to be used in a speech recognition system. When reading the comp.dsp post, I assumed the definition of "improve the speech quality" meant "improve the listening experience of a person".
> I assumed the definition of "improve the speech quality" meant "improve > the listening experience of a person".
Exactly!! I am thinking that adding some audio effects (such like flanger) to the decoded speech could masked out some of the embedded noise resulting from the encoding/decoding (ADPCM) process, so that people can feel the decoded speech better than without adding such effects. I just don't know if adding such audio effect is a common practice or just I am too stupid and bold to think that.