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Mark Ryle

Why only 74 min in SP mode?

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I bring WAV files into Sonic Stage library and then transfer them to a 74 minute minidisc with an MZ-RH1 minidisc recorder. I transfer them in MD mode on the MZ-RH1 and SP mode in Sonic Stage because the device I want to play the finished minidisc on is a Minidisc Deck JE530 which I don't think is capable of playing LP2 or LP4 minidiscs since it's too old. And anyway, I have an original first generation minidisc recorder I want to play them on too which won't handle LP2/LP4 either, from what I understand.

If MD mode is a transfer rate of 292 kbs, why will only 74 minutes of WAV files fit on the MD? Would it make a difference if I would convert the WAV files to mp3 first in iTunes? And do mp3 files transfer to the minidisc in MD mode?

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That will be 74mn if you record in real time in SP mode. 

MP3 transfer is more like a data transfer. And yes I think you can transfer much more than 74mn. Only for an unit which can read MP3 like RH1.

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55 minutes ago, Mark Ryle said:

If MD mode is a transfer rate of 292 kbs, why will only 74 minutes of WAV files fit on the MD? Would it make a difference if I would convert the WAV files to mp3 first in iTunes? And do mp3 files transfer to the minidisc in MD mode?

SP is not the same as (uncompressed) WAV (this you clearly recognize). The capacity of an MD is about 150MB. The capacity of a CD is between 700 and 800 MB.

Happy New Year!

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As an example, right now I have 7 songs on a 74-min Sony minidisc. The timing of the 7 songs is 32.29 total. Sonic Stage tells me I have 42.01 min free left on the minidisc. Add 32 min 29 sec plus 42 min 01 sec equals 74 min 30 sec. And Sonic Stage is right about that because I know from experience if I would try to add, say, 10 more songs on the minidisc, Sonic Stage would give me a box that says it cannot record the last 1 or 2 because there is not enough room on the disc.

The total playing time in SP mode always will come to something around 74 minutes. If the bit rate of SP mode is around the same as mp3, which I think it is, wouldn't I be able to get a lot more than, say 17 songs on an 74 min MD? A 74 min MD will hold approximately an audio CD's worth of content, from my experience. But the bit rate is much lower - a fraction as much as an audio CD, just like mp3.. If I make an mp3 CD I can put 70 or so songs on a 650 MB blank CD.

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I do know I could get a lot more onto the 74 min MD if I would use it in Hi-MD mode. The reason I want to use SP mode is that I need to be able to play it on my Minidisc deck JE530 which does not play LP2 or LP4 or Hi-MD. And i was just wondering if the oldest original MD's from the 1994 era can be formatted for Hi-MD. I know my 74 minute ones which were bought in the early 2000's can be used for Hi-MD.

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As far as I know, any regular audio MD can be formatted for use in HI-MD. Sony would have stated so otherwise.

About the time discrepancy between SonicStage and your calculations: Keep in mind that there are issues like fragmentation, possible bad sectors on the disc, and that SS is only giving you an approximation based on reading the table of contents, not from a full surface reading. Also, yes. You could stuff 70 or more compressed songs on 74-min MD... if it had the same capacity as a CD. MDs usually have a 160MByte capacity, compared to the 650 a CD can hold. The 74 minutes you get on an MD result from using lower-bitrate (compressed) recordings made to fit in a smaller medium.

Here's an MD technical Q and A. Hope this helps:

http://www.minidisc.org/minidisc_faq.html#_q1

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The bit rate of audio tracks on the old minidisc system is fixed at 292kbit/s, regardless of the original source. There's not much point in thinking in terms of file sizes or original bit rates, A 74 min MD holds 74 mins of audio, end of story (ok, double that for mono). That's roughly 17 or 18 four minute songs. 

A standard 74min MD has  about 140MB of data, about one fifth of a CD-R, which why your CD holds about 5 times the number of songs as your MD at a similar bitrate.

You should be able to format the oldest audio MDs to Hi-MD format, why not try and see.

You should also be aware that transferring in SP compatibility mode in Sonicstage degrades the quality to LP2 at best. If quality is an issue you're better off doing It the old fashioned way - real time, using a digital audio cable if possible.

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10 hours ago, Mark Ryle said:

As an example, right now I have 7 songs on a 74-min Sony minidisc. The timing of the 7 songs is 32.29 total. Sonic Stage tells me I have 42.01 min free left on the minidisc. Add 32 min 29 sec plus 42 min 01 sec equals 74 min 30 sec. And Sonic Stage is right about that because I know from experience if I would try to add, say, 10 more songs on the minidisc, Sonic Stage would give me a box that says it cannot record the last 1 or 2 because there is not enough room on the disc.

The total playing time in SP mode always will come to something around 74 minutes. If the bit rate of SP mode is around the same as mp3, which I think it is, wouldn't I be able to get a lot more than, say 17 songs on an 74 min MD? A 74 min MD will hold approximately an audio CD's worth of content, from my experience. But the bit rate is much lower - a fraction as much as an audio CD, just like mp3.. If I make an mp3 CD I can put 70 or so songs on a 650 MB blank CD.

I don't understand what point you are trying to make. MD is a compressed format. An MD holds much less than a CD. Therefore it won't hold as many songs, at a comparable bit rate. Simple mathematics.

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Ok, I do understand now. The format was originally designed to hold a CD's worth of audio even though being smaller in capacity but with the use of compression to 292 kbs. And I will try one of my original MD's from around 1994 in the Hi-MD format. Thank you all for your help.

I didn't know that transferring to SP in Sonic Stage degrades audio quality to LP2, but I've been listening to such MD's for about a week now and the quality is very good. i can't distinguish it from the original CD's. And I'm not archiving the music. I'm just using the minidiscs to listen to on a daily basis. I have the CD's in iTunes in WAV.

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