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Showing posts from February, 2008

comparison between mp3 and wma codecs , (linked pdf file )

You can find it in these links (direct pdf files , please use "save as" with the right mouse click , or press ctrl + for opening into your web browser. The file is just 200 kb. multiply article geocities article in case the previous does not work The file shows the methodology i use plus a big table with compressions in wma FhG and lame mp3 vers 1 codecs in terms of spectrum analysis This file has been originally edited on 2005 Please leave here you r comments

Oversimplified listing of the MP3 compressions

This is an notice shown on the  same webpage and also refered here separately.  This just describes the various compressions levels and thier main use Here is a oversimplified listing  of the MP3 compressions :Notice that as the number in the left pane is higher ,  the  higher the filter and thus higher fidelity audio. The higher numbers can offer the abilities or the  lower numbers  too.   Notice: The program  used  for analysis  is Music match jukebox that offers  the  curves shown in my blog above kbps approximate usage - 8 - 11 kbps suitable for recording telephonic conversations , voice  recording . narrowband AM radio 16 the above plus high fidelity  speech, AM radio, low fidelity streaming radio 24- 32 kbps high quality speech , AM radio [medium and shortwaves ] 44-56

The reason not to use low MP3 compressions!

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Notice : this aricle is my 2nd arcticle on mp3 tech and appeared on 31-5-7 on multiply site . The main reason writing that article i s that many  people  are using  low level MP3 compressions (as 192 adn 256 )  that i do not think  are  so necessary  since per  my measurements  128 kbps are more than enough. To my year  wma's  of the level of 48 kbps  have neatly the  same level . --------- Given that many users on Multiply rip or covert their music in quite big files of over 7.5 MB fr a 4 minute song ,i decided to write this article to explain why it is not necessary to use very high sampling rates. At same time I will notice to you why I use the WMA format in 48 kbps to include mass material into a small MP3 player as shown in my previous reviews It is important to advise you that I was in the audio technology and HiFi's since 1980 , including also the MP3 tech form ca 1997 and my first ever MP3 player was with CD on 2000.Also i used several professional equipment the old
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MP3 comparison chart of two encoders Please notice that this is the first article i wrote abut mp3 tech analysis , depicted on 96-97 and appeared on my old geo site UPDATES ( i think made on 91-92 ): Following a series of upconvertions adn other experiments that itme i have found soem other peculiarities that are main to Musicmatch: Upconverting monophonic bit rates to stereo bit rates can cause stereo widening of these monoral audios. The lowest stereo mode i found or used was the 24 kbps UPconverting to higher bandwidths may cause / produce 'reaction /reactance carriers' . For example a 8 kb ( of 8 kHz) upconverted to 24 kb cana cause ahigher freq whistle to be heard, that can be soemtiems very annoying. please notic that this does not only happen between MP3 converions but also to convert one WAV file of 32 kHz to an MP3 file of 44 kHz bandwidth . There was indeed one reactance carrier of ca 16 kHz . The problem for this case has been corected

Crash testing with Napa DAV315

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Crash testing with Napa DAV315 version blogspot original article here in Geocities Following my interest in MP3 technology the last years and the big list in MP3 in songs recorded throughout the years, the information read from many magazines and e-newsletters and web pages , I have finally decided that a MP3CD player could be the ideal solution for me to replace my walkman and my other CD player. This was also the result after a recent purchase of a CD recorder whose main use will be at first for any necessary future backup at first as well as for collecting this material just in MP3CDs The S/N of the model is DB02007083 manufactured April 2001 As you know I like to make inspections of any interesting gadgets. And here is an exhaustive analysis for the Napa 315. And much better as I recently bought a CD recorder that helped much in makling a line of Cds for the testing and normal playback of my big collection of more than 2500 songs from tapes , Cds and SW recordings .

SINPFEMO A better signal tech analysis by using F/TDM

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SINPFEMO ------------- A better signal tech analysis by using F/TDM analysis drawings in specialized reports (version blogger ) Considering that SINPFEMO does not 100 % cover the truth from listeners point of view in regards to signal readability QRM and fading I have used for more than 4 years derived from more specialized monitoring equipment such as Hewlett Packard , Rohde & Shwartz etc I think however that both terms shown below are very easy to understand however there is still a little analysis behind them on how i used them so far. #1. Frequency domain analysis ...................#1b. About computer DSP analysis on FDM #2. Time domain analysis ( fading analysis) ...................#2a.Cases of 'Short' time fading found on SW: ...................#2b.Cases of long term fadings #3. More advanced way for domain analysis #4 Using R75 and specialized programs New.gif (908 bytes) ....................#4a Smart Icom 32 and R75 ....................#4