Recording duration shorter than the original [SOLVED]


First of all, I’m a French speaking guy, so please be comprehensive.

Now, here’s my problem :
I decided to use Audacity looking forward to transferring my mini-discs into my Media-Player library (on an external hard drive).
At my first (and last) attempt, I noticed that the duration of the recording was shorter than the original one! It was about 6’ shorter to the original duration of 78’.
This difference is noticeable when you listen both.
I didn’t find any solution by exploring the app (I’m not used to it) neither by reading tutorials and forums.
Does anybody have an idea or, why not, THE solution?

Thank you…

PS: my system is:

  • Audacity 2.1.0
  • Windows 8.1; operating system 64 bits, processor x64; sound card Realtek High Definition Audio
  • MD Player Sony MDS-JE500, connected to an external sound card AUREON 5.1 USB mkii from Terratec via an optical cable, itself connected to my PC with USB.

I believe the MiniDisc uses a sample rate of 44.1kHz. In the lower-left Audacity window, what do you see for Project Rate? …For example if the data was coming-in at 44.1kHz but your soundcard and Audacity “thinks” it should be 48kHz, that’s about the same ratio as 72/78.

If you see 48000Hz, try Edit → Preferences → Quality and change the default sample rate to 44100Hz and record again.

Or if you don’t want to re-record, try the Change Speed effect.

Normally, the sample rate is not a problem because the driver correctly communicates the sample rate between the hardware and the application, and the driver can change the sample rate, but it can happen with an optical connection.


Thank you DVDdoug for your answer.

First, I’ll not be able to try something on the app before Wednesday evening or Thursday afternoon (local time : Greenwich + 2).

Whatever, I’m sure that the rate in the right lower case was on 44.1 khz, as recommended by the manual or in different tutorials.

Could the problem be at the external hard drive level? Or the optical line? …

All ideas are very welcome and I will try them as soon as possible.

Thanks again and see you soon.

You might have to look at your USB soundcard to see what sample rate that is set to. Or if there are no settings on the card or in its control panel, open Windows Sound, Recording tab, right-click the soundcard, choose “Properties”, click the “Advanced” tab then look at the “Default Format” sample rates. The card might be set to 48000 Hz when the signal from the optical cable is 44100 Hz.

If instead it is a problem of sample rate conversion between the sound card and Audacity, try Windows DIrectSound or Windows WASAPI host in Audacity’s Device Toolbar with the Exclusive Mode boxes enabled for the soundcard in Windows Sound (look underneath “Default Format”).

By the way the current Audacity version is 2.1.2:


Hi Gale.

Thanks for your answer, that seem on the same bases than DVDdoug’s one.
Both you bring light in the darkness of my knowledge.

I’ll try it as soon as possible and give you a feedback right after.

Have a nice day.


Hi Gale & Doug.

You were right, the problem lay in the optical connection between the MD player and the external sound card. I found on the net information regarding this external sound card : settings to 48 kHz when connected with optical line-in and to 44.1 kHz with analogical one.

Even if I open Windows Sound, it’s not possible to change the sample rate, and the “Default Format” window in advanced properties’ sound card show the same 48 kHz sample rates for analogical connection. But with the analogical line, no more trouble and 78’ are 78’!

God, you have ensured the universe’s safety, there is no time dilatation!!

To be complete, I should add that, thinking that an optical connection could be better than an analogical one, I tried different solutions (change the sample rate in Audacity, activate the pc sound card, change the recording device…) and nothing seems to be working.

And to finish it off, I will say I found the most detailed data on the sound card and how it works etc… by a website called Sure, it’s a website intended to Linux users but perhaps it could be interesting for advanced people like you.

So, thanks to you again.

And now you can put on this topic “quickly done, well done : SOLVED!”

Of course an optical connection would theoretically be preferable. I think DAT machines often default to 48000 Hz (the highest rate supported by DAT) so this is why optical connections often default to 48000 Hz.

Assuming the pitch was also faster than you intended, you could record with the optical cable then use Effect > Change Speed… at -7.692 per cent to correct the length and pitch. This does not create artifacts in the audio. If you have upgraded to 2.1.2 then Change Speed has a length control and you can simply enter the new length.


Hi Gale.

Sorry for this delayed post but I was on holidays and now that I’m back home, I’m also back to audacity.

And indeed, by introducing the real length into the Speed Change option, everything works right. And so easy.

The last annoying issue is in tagging the songs. On my MD-covers, due to the limited place, I only wrote the Artists ‘names. The best way I found is to use Soundhound, then manually introduce the names of the artists and the tracks before exporting them to the external hard drive, and finally use “the update metadata and cover art” function in Windows Media Player. I didn’t find a better way on this forum or anywhere else. So, if you have one, it will be welcome…

Whatever, thanks for your work in this forum!


I’ve marked this topic as [SOLVED] given you find it OK to use Change Speed.

You could perhaps export no tags from Audacity and make all the changes in Windows Media Player. It can guess tags from an online database to get you started.