Audio minutes per CD??

[Rick]

Hello

I am a first time user on this board. My question: How many audio minutes can I fit on one CD(no music only talking). I am needing to make a audio CD that has up to 7 hours of verbage. I am using Pro Tool as my recording device. I am just starting a project and I need to know what my parameters are.

Thanks,

Rick

 

[vdi_nenna]

74 minutes for most cds. There are some 80 minute. I'm not sure if you record something in mono that it will require less space, giving you more time. Try asking this question at

http://www.audioasylum.com

They have serveral different forums there. A few on digital.

MP3 can store many hours worth of audio on one CD, but not all CD players can read the MP3 format.

good luck.

Vince

[Edited by vdi_nenna on 03-05-2001 at 02:21 PM]

 

[Eric]

CD Length

I thought I remember hearing that CDs were designed to hold 77 minutes and several seconds - enough to hold Beethoven's 9th Symphony in its entirety.

 

[Schaef]

Length

I believe technically its about 72 minutes, but I've seen
longer on standard audio CDs. It doesn't matter if the
recording is spoken word, classical music, stereo, or mono,
it all takes the same amount of space. The format is set
at 44Khz/16bit stereo recording irregardless of the actual
recording. Also, since its not compressed, the content
doesn't affect it either. It's not until you get into the
things like Dolby Digital, DTS, MP3, and things like that
do you get to different space requirements depending on the
quality needed and the number of channels recorded.

Hope this helps out!

P.S. - to Eric, I do believe it is Beethoven's 9th that is
the reference used to determine the length of a CD.

 

[JazzFrac]

It Depends

An 80 minute Audio disc will hold just over 78 minutes, when recorded with certain software, most of the time, though you're only allowed 74 minutes with standard software. The first option is probably what they use to record the properly played 9th.

 

[spootyguy]

Also, some software allows you to 'overburn' CDs, which is not recommended but if high quality CDs are used this can add several minutes to the recording. Cheap CDs tend to fail.
This is not one to count on though, as it depends on your CD recorder, the disc quality and the software.

 

[Nisbeth]

I think spootyguy is right - it depends on the recorder and software. I have two cd's which are 79.56 and they work fine in every player I have tested them in. They are made with Toast Pro for Mac and my Yamaha 8424 recorder, but other combinations might yield different results.

/Regards

 

[PassFan]

Beethovens 9nth

I heard that story as well when I was in school but there really is a technical reason that has to do with the bit rate and quantization. Ken Pollman is the digital expert. Used to teach at Miami I think. Has a couple books out.

 

[WhtCastle]

OK, time to flex the geek muscles.....
The ussual CD is a 74minute disc, now depending on:
a)the burner
b)the burning software
c)the CD

It will either hold 74minutes, or more. (I've gotten 76minutes out of a few.)
By lowering bitrate, going to mono etc. DOES NOT MATTER
Audio does not work with files sizes, it uses minutes. You could burn a 74minute wav file that is 3gig on a cd. You could burn 20 mp3tracks that are 50meg in size only, but that is 74minutes long, and fill the CD. Again; with audio, FILE SIZE DOES NOT MATTER. Same goes for 80minute CDs, and I've gotten those to hold just under 82minutes.

Now for the '7hour long CD', Schaef said it right, you can't do normal audio. If you want my recommendation, get an MP3 CD-Decoder, and take your recorded talkin and downsample it to mono, and at the most 96kbps, but depending on size that yeilds, maybe somethin down to even a 48kbps. On that note (and I'm probably wrong) I think I read somewhere the quality of a phone conversation is roughly equal to 8kpbs. I hope this helps somewhat.

 

[hifiZen]

ummm... i think your burner would run out of media before it could fit that 74-minute 3GB .wav on your disc ;-) There *is* a limit to the actual number of bits that can be put on a CD.

 

[johan]

The standard audio CD is 650 MB. The standard audio format is 16 bit 44,1 kHz. Putting that together means that the standard lentgh in minutes for a standard audio CD is about 74 min (around 10 MB/min). You can record whatever you want, but you have first to convert all audio to 44,1 kHz, 16 bit. Sometimes the recording software is able to do this.
There are, however, NON-STANDARD audio disks. You can buy 80 minutes, 90 minutes and I have even heard rumors about 100 minutes disks. I know at least that 95 minutes disks have been made using 90 minutes media and overburning. See http://www.cdrinfo.com. It is very common that music CDs exceed the 74 min. Using special software it is possible to measure how much you could put on (overburn) a CD (for instance Feurio). I don't know how standard CD players react on CDs longer than 80 min. To be able to put more music on a CD, convert for instance the music to MPEG-2, burn it with Nero, and play it in a stand-alone DVD-player. Or even better, convert it MP3 and use a modern standalone DVD-player (for instance Philips DVD-712) that plays MP3-audio.

 

[dsanders]

As far as using a DVD player, on older DVD players that won't play CD-Rs sometimes they will play CD-RWs. Also you may have to burn it as a video CD, it all kind of depends on the DVD player. I agree though if you are wanting 7 hours on 1 CD MP3 is gonna be your best bet. I burn 80 minute CDs all the time, I use Adaptec Software (I'm not a big fan) but for more advanced stuff I suggest Nerio. It is better suited to doing details like setting pauses in between tracks and it allows overburning if the CD allows it. Good luck,
David

 

[WhtCastle]

ummm... i think your burner would run out of media before it could fit that 74-minute 3GB .wav on your disc ;-) There *is* a limit to the actual number of bits that can be put on a CD.

Doesnt matter how big the wave file is, as long as the time it plays is 74 (or 80, whichever disc your using) it will fit the disk. Don't ask, it doesnt make sense, but that's how it is........

 

[AudioFreak]

ummm... i think your burner would run out of media before it could fit that 74-minute 3GB .wav on your disc ;-) There *is* a limit to the actual number of bits that can be put on a CD.

Doesnt matter how big the wave file is, as long as the time it plays is 74 (or 80, whichever disc your using) it will fit the disk. Don't ask, it doesnt make sense, but that's how it is........

Yes and No. Audio CD's as in the ones you play on your standard CD player use 16bit, 44.1kHz PCM format so the software converts the file to a 16bit, 44.1kHz wave file before burning ..... this is the only format most standard CD Players know how to play ..... so yes .... if we are talking about a audio CD, a 3GB audio file can be burned so long as it is no longer than 74 mins (cause of the format conversion that takes place ..... such a file will be reduced to just under 650MB) ...... not all burning software is capable of the format conversion in which case you will have to do this yourself before burning.

 

[johan]

Never heard about an audio file that is 74 min. and 3 GB. In theory, 96 kHz sampling rate, 24 bit depth and 74 minutes should give 2439 MB (2,38 GB) of audio data. The relationship is simply mathematic. For a regular audio CD: 74 min. = 4440 seconds. Sample rate of 44100 samples/second. 44100 * 4440 = 195.804.000 samples. 195804000 * 16 bit = 3132864000 bits. 3132864000 / 8 = 391608000 bytes = 373,47 MB (remember: 1 byte=8 bits and 1 kbyte = 1024 byte). This is mono. Multiply with 2 for stereo and you get 746,9 MB. 746,9 MB you ask? OK, an audio CD uses the full capacity of the Compact Disc. A CD is written in data sectors of 2352 bytes. But on a data (computer) CD, only 2048 bytes is used for data. The other 304 bytes is used for error-correction, sector numbers and other things, leaving only 650 MB available for data. An audio CD uses the whole 2352 bytes sectors, which means that it can use the full capacity of the disc. So 74 minutes is strictly speaking 747 MB when talking about audio CDs.