May 21 2008

Morse Code file format changed

Published by at 4:07 am under Ham radio,Morse Code,News

I have changed the file formats for the morse code audio files and also changed how the files are served on the web page. For many years the files were being created as sun format .au sound files, these are easy for me to create programmatically but can be rather large files, especially for QSOs at the slower speeds. Since I moved hosting companies this has caused me to run through my allocated bandwidth in about 5 days! I’m upgrading the bandwidth but at the same time my hosting company very helpfully installed some software packages to enable me to ditch the .au files in favor of the more modern mp3 format.

Mp3 is a compressed format so the files are much smaller and also mp3 is a far more friendly for modern browsers and of course will now work with our favorite mp3 players. In the short term I am using a flash mp3 player embedded in the web page to allow you to play the files directly from the page. Please leave me a comment if you have problems with this. I’m also going to be improving the look of the web pages as they haven’t changed in ages and are certainly showing their age, particularly now I’ve upgraded the rest of the site.

Morse Code Podcast? – In the longer term I’d like to try and set something up for a daily morse podcast so that you can get a new QSO or perhaps some other content as morse code via iTunes or a similar podcast feed service. I think all the bits are in place at this point, I’ll just have to find some time to code it up. If you have any thoughts on this, please let me know.


Simon, AA9PW

33 responses so far

33 Responses to “Morse Code file format changed”

  1. mpechneron 21 May 2008 at 4:56 am

    I think the sound in the new files are harsher sounding. I like the tones used for the AU files.

  2. Simonon 21 May 2008 at 4:59 am

    I don’t disagree with you – I need to see where in the process this is happening and then hopefully I can tweak the settings so the sound quality improves. Given the file conversion from .au through to mp3 and the associated compression, I think there is likely to be some degradation associated with this but I will see what I can do to improve the quality.


  3. Dominic Beesleyon 21 May 2008 at 11:33 am

    I love getting the news each day through your site, it’s helping me to get up to speed copying morse after only a couple of weeks. I did like the old sound though, this new format I find very difficicult to copy.

    I think you might want to reduce the compression a little? And possibly have a less sharp “attack” to the notes.

    Excellent website though, well done and keep up all the good work!


  4. Al Barkleyon 21 May 2008 at 9:43 am


    I’ve loved coming to your site to practice my code. Unfortunately, the files are now unreadable in the new format. The audio is now a set of rather raspy chirps and cannot be recognized as Morse Code. In addition to the audio issues the files seem to be compressed. I’ve downloaded the latest flash plugin with no difference. I really hope the issues can be sorted out because I’ve come to rely on your site for my code studies.


  5. Bruceon 21 May 2008 at 11:34 am

    I do not hear any audio,
    and I do not see anything to click on to control the audio.

  6. Simonon 21 May 2008 at 11:35 am

    @Dominic – I am using the ‘lame’ mp3 compression package ( (yes that’s really what its called!) which is meant to be pretty good so I think I need to play with some of the settings to improve the quality. I will do some tests and post the different versions of the files so we can see what works the best.

    @ Bruce – The interface should look like this: but if you aren’t seeing anything then perhaps you dont have the flash plug-in installed in your browser. I will include a direct link to the MP3 file that you can click on so the lack of plugin won’t make the site unusable for you.

  7. Simonon 21 May 2008 at 11:40 am

    I’ve done some experiments with the different file formats. From what I have done so far, none of the mp3 compression options do a decent job, particularly with code at high speed.

    I also explored resampling the existing .au file and this has been far more successful. If you generate some code now you’ll see the mp3 link and also the link to a resampled .au. To my ear this sounds pretty good and is about a third of the file size of the original .au file, let me know what you think.

    30wpm sample: Original .au file (103k), Resampled .au file (32k)

    If this resampled version is acceptable then I might go with that for now, as that will make a good dent in the bandwidth without making the audio unusable.

  8. Tom Bon 21 May 2008 at 12:10 pm

    I just recently found your website and started learning “eish” and “tmo”. I’ve only logged on a few times and the .au files were excellent. This morning I logged on and found the new flash files. I must be doing something wrong as the files sound like clicks. How do I change this to sound more like tones?

  9. Tom Bon 21 May 2008 at 12:46 pm

    Thanks for creating this site. I’ve always wanted to learn code and this seems to be working for me. I would like to continue using the resampled .au files if they are available because they sound so much like the eish files I’ve started copying. I’m also trying to listen to the tmo files but concentrating more on eish for now.


  10. Dominic Beesleyon 22 May 2008 at 7:29 am

    Hi Simon,

    The new mp3 is if anything a bit worse, it looks like something odd is going on with it possibly overloading or something. LAME usually works quite well, I use it to reencode all my music for my car stereo, I record in ogg format and it usually works ok.

    If you’d like post up or email your code and I’ll take a look.

    One thing that can upset encoders is sudden jumps in value. So if you’re going from linear samples to mp3 make sure you don’t have any sudden “jumps” as these overwhelm the compression algorithms and get amplified whilst the “real” sound gets lost.

    The resampled au is if anything a bit nicer on the ear than the original, and sounds more like a real rig on HF.



  11. Al Barkleyon 22 May 2008 at 11:15 am

    Hi again,

    I’m sorry to say that the new file format has missed the boat. After having downloaded the latest version of the plugin and restarting the computer, I can now hear recognizable code. However, the dits sound like clicks and the dahs are like odd longer versions of the same with an uptic at the end. It’s very distracting and difficult to copy. Something is wrong. It really is too bad. I’ve learnt my code on this site. Hopefully, a tweak will make everything right.

    Al Barkley

  12. Al Barkleyon 22 May 2008 at 11:17 am

    Hello again,

    The .AU format works for me. I didn’t notice it on my first go around.

    Al Barkley

  13. Simonon 22 May 2008 at 2:25 pm

    @Dominic – If you can help with lame that would be great. Here’s what I am doing at the moment. I use sox to convert the .au to .wav, that conversion is fine, I’ve looked at the waveforms and listened to the .wav and it sounds identical. From there I pass it into lame to convert to mp3 and I have tried a variety of options, here’s the current settings:

    /usr/bin/lame –silent morse_file.wav morse_file.mp3 -V2 –vbr-new -q0 –lowpass 19.7

    I messed around with a variety of conversion options using Lame and also iTunes. I popped them into GarageBand as a way to see what was going on. Here’s a screenshot:


    I had to convert the original .au to .wav and then to .aif in order to get into GarageBand, this added some noise to the sound but the first line is pretty close to what things should look like. You will notice that it contains a lot of sudden jumps, the sound goes on and off ‘instantly’, there is no gradual rise and fall in signal and that may be causing the issue with the compression.

    The next track is the iTunes conversion of the .wav to .mp3 – its better but there are artifacts creeping in. The remaining tracks are various mp3 files created from the .wav using LAME at different settings. Its doing weird things like dropping out the middle of the dah’s and degrading the signal in other interesting ways, depending on the settings.

    Hopefully I just need some help with the LAME parameters in order for this to work but I dont really know the best way to tweak it. Here’s a link to the .wav file that I used for these experiments if someone wants to play with it to get a better conversion:


    If I need to do something to smooth out the original sound for the conversion to work, that’s probably doable but I’ll have to dig back into my code and figure out how to create .au binary files!


  14. Simonon 22 May 2008 at 10:03 pm

    I have removed the mp3 audio for now in favor of the resampled .au which I think sounds fine and is a much smaller file. I’ll continue working on the mp3 conversion and if I can get it to sound respectable, I’ll add it back in.

  15. Tom Bon 23 May 2008 at 3:05 pm

    Am I on the right track regarding reflex copy? I read all the information on your other pages and the KOCH method makes sense. I set the speed at 15 wpm and selected the “EISH” group of letters. I keep wanting to say the letters in my head, my pen can’t keep up, and I fall behind very quickly. Having read the “reflex” comments, I try to write the letters without thinking about them but I still fall behind. After several minutes or so I take a break from the four letters, and then select the headline news file at 15 wpm and just listen to the rythm without attempting to copy any letters while getting a drink of water or something.

    I’ve wanted to learn code since the early 1970s and this method seems like it will work for me. Thanks again!


  16. michael pechneron 24 May 2008 at 1:43 pm

    Using kde amarok under linux the last word of the morse code sample is not played. I tried multiple groups and the same happens. Also the firefox embedded mplayer pluggin does not recognize the au file as valid. it won’t play it.

    I am trying to use my asus eee 901 running xandros.

    Right now your morse code practice files are the only thing that requires I use my windows PC. I’d love to not need to boot it.

    If here is a tweak you can try on the au file, I’d be happy to be a beta tester. Same for the mp3 files. I can test on win, mac and linux.

  17. john mulkeyon 25 May 2008 at 5:52 am

    Hi Simon, first of all thank-you for all the effort you have put into the site. Much appreciated.

    In case you are still engaged in the analysis phase of things may i offer my observations with respect to the code generator. The actual tone sounds to be very close to a “b” one octave above one step over concert “a 440″ . The attack time is wholly reasonable. The waveform sounds pleasant. Here’s the interesting part…

    While the decay time is also reasonable each dit or dah is ghosted by what sounds like the same frequency though mostly sinusoidal in content and lasting between 200 and 350 milliseconds- present just barely long enough for my brain to recognize it as such.

    take care bud,

    john ae5gq

  18. Simonon 25 May 2008 at 9:38 pm

    Continuing the mp3 saga, we found out that lame on our server was doing strange things so we switched to lame 3.97 (latest stable edition) from 3.98beta and that seems to have made a big difference to the audio quality. I’ve put the mp3 links back in again (the .au is still there) and I would welcome some feedback on the quality this time around.

    @John M. – Interesting observations about the ghosting. I wonder how much the hardware (speakers, etc) comes into play with some of these things. The software writes the audio file directly, with the sound either on or off (absolute silence on the track), so there shouldnt be any ghosted sound in the actual file – perhaps its a ‘feature’ of the hardware when playing this through speakers?

    @Michael – Let me know how the new mp3 files sound and if they work OK on your linux platform. I dont know how this will work for you but one of the folks on the Lame-dev list reported good results with the MOC player on linux ( so that might be worth a look.

  19. michael pechneron 26 May 2008 at 1:21 am

    the new mp3 is working great on my asus eee 901 under linux using firefox.


  20. Dominic Beesleyon 28 May 2008 at 2:07 pm

    Sorry Simon, I’ve only just had a chance to look back after being away for work. The quality now is, I’d say, about as good as can be hoped for – and the files nice and small.

    Well done, I’m almost able to do the headlines at 5/18 now!


  21. Dominic Beesleyon 28 May 2008 at 2:13 pm

    Just had another look at the original .au files, and these still seem to “overshoot” a bit at the start / end of each tone. I’d check the lead in/out code for the original .au generation, it looks like its doing a soft lead in/out but that the parameters are a bit off. Or perhaps you’ve reduced the amplitude of the middle part of the tones but not the target of the initial envelope?



  22. Gary Pielakon 29 May 2008 at 4:52 am

    The new mp3 format sounds good. Thanks! I look forward to doing the headlines each morning.

  23. Suzyon 29 May 2008 at 12:07 pm

    I listened to the alphabet eish and ABC news on 5-29-08, and they just sounded like “dzt dzt dzt dzt dzt” with each “dzt” apparently being a whole letter run together, and of slightly different lengths, instead of the nicely toned beeps that had previously been on the website. I hope this gets cured soon.

  24. Bradon 03 Jun 2008 at 10:14 am

    FB on the podcast proposal. It will be a great service to those of us who are dedicated to improving our skill.

  25. Jimon 15 Jun 2008 at 3:27 pm

    Simon–Very classy Website, cleanly designed. The MP3 code comes through perfectly on this old Windows PC, which does use iTunes/QuickTime as its audio player.

    Question: Can I save the MP3 files for transfer to a portable MP3 player for practice on the road? When I right-click, I don’t see a “Save file as…” choice. –Jim KJ3P

  26. Thelmaon 08 Jul 2008 at 10:34 am

    I liked the au files better. They could be downloaded and played over and over at my convienance.

  27. Douglas Cruteon 26 Aug 2008 at 4:05 pm

    THanks to your site and and the QRZ site and also Gordon west Excellent exam book on the Extra Class licence test I was able to pass my Eliment 4.

    again thanks


    Douglas Crute

  28. Roger |G3LDIon 10 Nov 2009 at 1:23 pm

    I notice that several others say that the audio is harsh. I don’t like to complain
    as you put so much work inot this, but I use your program among others for my
    Morse Classes here in the UK.
    I am not sure how he programs his audio, but take a look at TEACH4 by ZL1AN.
    His keying and audio are superb, tone adjustable and a T9X note too. Now if yours
    was like that it would be perfect!
    TEACH4 does not have inbuilt numbers and selectable letters and punctuation
    however, just text files.

    Many thanks for the program though. 73 de Roger, G3LDI

  29. Johnon 19 Nov 2009 at 5:47 pm

    Any update on down loading mp3 files.


  30. Ruth Hodsdonon 20 Apr 2010 at 6:44 pm

    Hi, I’ve been using this site for a while and it’s great, the best I’ve found anywhere. But suddenly the MP3 player is not displaying anymore. You can see the characters that would have played after you press text/questions but of course w/o the MP3 I never heard them. This makes day 3 that it hasn’t worked. The laptop has very little on it, I’ve run disk clean up and defrag. Everything including your site runs fast but the MP3 is mia. Any idea why? Thank you and 73, WW1N

  31. Ruth Hodsdonon 21 Apr 2010 at 8:29 am

    Hi again, the AU version is working fine now with my Quick Time media so I’m back in business. Maybe later I’ll find out what happened to the MP3. It was definitely on my end as I found from friends that the MP3 version is still working for them. Thank you.

  32. jim christieon 01 Jun 2010 at 1:45 pm

    Just a quick note . . Your practice site is great. I am a Korean vet, was classified as a hi-speed code operator. Had not copied code in 58 years . . In one week I was up to 15 wpm..A donation is on the way to you

    Thanks – -

  33. test2on 25 Jul 2011 at 4:43 pm

    I do not know whether it’s just me or if perhaps everybody else encountering issues with your site. It seems like some of the written text on your posts are running off the screen. Can someone else please comment and let me know if this is happening to them as well? This might be a issue with my browser because I’ve had this happen before. Cheers

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