[hpsdr] TeamSpeak audio 2009/June/27 - compression

[Mike Naruta]

That is an excellent idea Alberto.

I think the TeamSpeak sampling was reduced
last year to try to reduce the dropouts.  I
noticed the recording still has some.  I have
had Comcast here to replace my service drop
coax.  When I still was experiencing problems,
Comcast suggested my LinkSys router was a
problem.  I bought a new LinkSys router and
the packet loss still occurs on Comcast
broadband, but not on my dial-up line.
(No DPC problem.)  I listen to both dial-up
and Comcast at the same time on different PCs
and it is interesting to hear the Comcast
fall behind with an echo effect.  Usually
when the person drops the PTT it catches up
for the next person, then the delay echo
increases in steps.


I normally use Audacity to convert the
TeamSpeak .wav file to a 24 KBPS .mp3 file.
Perhaps I should increase the .mp3 file to
48 KBPS?

I have uploaded a .zip folder of sample
files of about the first 7 minutes of:

The edited file at 24 KBPS

The edited file at 48 KBPS

The un-edited file at 24 KBPS

The edited file at 24 KBPS with a 50 per cent tempo reduction

< http://www.hamsdr.com/dnld.aspx?id=992 >


Please compare the 24 KBPS and 48 KBPS files.
My old ears can no longer hear above 10 KHz.
I can upload at 48 KBPS if desired, the file
size is twice as large.

You may compare the edited and un-edited files
to listen for the editing difference.

I also used Audacity to make a 50 per cent tempo
reduction as an example for non-native English
speakers.  You can use Audacity to change tempo
to help comprehension.  When listening myself,
I usually increase the tempo by 50 per cent to
help hold my attention.


Mike - AA8K




Alberto I2PHD wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 
> 
> ------------------------------------------------------------------------
> 
> Mike Naruta wrote:
>> Here is a question for those who listen to the
>> file from HamSDR:  would you rather have the
>> original recording, or the edited version?
>>   
> My personal (very personal) comment is that in my opinion there is too much
> compression, not time compression, but space compression...
> I don't know if that was done by you, or is the result of the Skype software
> (if that is what was used). Anyway the net result is that for my ears of
> non-native English language speaker, often there are problems in 
> understanding
> what is said... problems that I wouldn't have, were I listening to a non 
> compressed
> original WAV file, without sound artifacts caused by the compression (e.g. a
> severe lack of the high pitch components of the human voice, very useful for
> a better understanding).
> 
> But of course I am not suggesting to change anything, it is just a personal
> problem caused by my non perfect grasping of spoken English, in presence
> of high rates of compression.
> 
> 73  Alberto  I2PHD
> 

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