# How big HD for MP3 music collection?

Discussion in 'Archived Threads 2001-2004' started by Patrick Cate, Dec 30, 2001.

1. ### Patrick Cate Stunt Coordinator

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Hi, I'm considering converting my entire CD music collection over to MP3's on my computer, but I'm having trouble estimating how big a hard drive I would need to store my collection. I estimate I have about 300-325 CD's

which I would convert to MP3 at 320kbps constant. Is there a computer program or some other method that could give me and estimate (even a rough one) about how big a hard drive I will need to buy? I appreciate any help.

2. ### Chris Wittry Stunt Coordinator

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This is just my estimate, but in my experience here is how the math works out:
320 kbs * 8 = 2,560 = 2.56 MB / minute
So 325 CD's with an average of 50 minutes per CD would be:
325 * 50 * 2.56 = 41,600 MB or approximately 42 GB, so you could go with a 60-80 GB drive to leave yourself pleanty of room for expansion. Hope this helps.

3. ### Rob Gillespie Producer

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320 constant would be overkill if you're using the right encoder. Take a look at this site for more info:
www.r3mix.net

4. ### Ken Chan Producer

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Hmm, looks like there are two separate math errors that almost cancel each other out To convert bits to bytes, you divide by 8, not multiply; and you forgot to convert seconds to minutes:
320 Kb/s / 8 bits/byte = 40 KB/s
40 KB/s * 60 sec/min = 2400 KB/min
So at that slightly lower rate and an average of 50 minutes a disc:
2400 KB/min * 50 min/disc * 325 discs * 1024 perK = 39.936 billion bytes (hard disk marketing size) or about 37.2 GB
To approach it from a different (and most conservative) direction, a CD can hold 74 minutes, so:
40 KB/s * 60 sec/min * 74 min / 1024 K/M = about 173 MB per disc max as MP3
which is about 1/4 the size of CD. That figures, given that the data rate of CD audio is:
16 bit * 44100 Hz * 2 channels / 8 bits/byte = 176400 byte/s
which is about 4 times the data rate at 320 Kb/s.
(You may know that the CD-ROM data rate is 150 KB/s, or 153600 byte/s -- how does that figure? Well, CD audio sectors are 2352 bytes, while CD data sectors are 2048 bytes or actual data with the other 304 bytes for additional error correction. Both use 75 sectors per second. I mention this because it took a bit of poking around to figure why they "didn't add up", and in case I forget this, someone else might be able to remind me )
In case you decide to use a lower bitrate, the formula for calculating full CDs, where X is the bitrate is roughly:
X kb/s * 0.542 = MB/disc
320 --> 173 MB
256 --> 139 MB
192 --> 104 MB
//Ken

5. ### James Reyes Stunt Coordinator

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Personally I would rather use a VBR encoding. Parts of songs may require a rate of 320, but hardly all of it. That's why Variable Bit Rate seems like such a no-brainer to me.
As for hard drive space... well, if you are anything like me, you will need as much as you can lay your hands on. There is no such thing as enough space.

7. ### Rob Gillespie Producer

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My entire CD collection, which consists of about 250-300 titles (around 4600 tracks) takes up around 27-28Gb. All have been encoded with LAME using the 96-320kbps VBR settings stipulated by www.r3mix.net

8. ### John Thomas Cinematographer

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But what again are the cons to using VBR? I recall skimming the instructions (as I am apt to do) and picking up something about VBR may cause some problems with encoding, particularly during multiple vast differences (ie: glitches and audio 'artifacts').
Otherwise, I'll cast another vote for it. Just makes good plain sense.

9. ### Rob Gillespie Producer

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I think with Lame there aren't any 'cons' with using VBR. Lesser encoders may be different.

The 'cons' are more likely to be with playback on other equipment. Some MP3 hardware has trouble handling VBR, some require Joint Stereo mode to be used, blah blah.

10. ### Chris Wittry Stunt Coordinator

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Wow, I know my math sucks sometimes, but I guess at 3:30 am it really sucks!

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I think that some mp3 players might not like it if you use ID3 tags on VBR files. I never do anyway, I just make sure my naming scheme for the files is sensible.

12. ### AaronNWilson Second Unit

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wow 300+ CDs yummmmmmmm .
Aaron

13. ### WoodyH Stunt Coordinator

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I've been thinkiing about this off and on for a while myself. Last time I made a guestimate, I figured it would take about 89-90Gb to .mp3 my entire collection (1100+ CD's) at about 128kbps...if I push up to 160kbps VBR, I'd probably be closer to the 100Gb mark!
Suffice to say, I haven't done it yet...though I keep wanting to pick up one 80Gb drive to get started, then put another in if I run out of space on that one.
Perils of being a sometime DJ - _way_ too much money spent on music over the years!

14. ### Hugh M Second Unit

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so once you spend all that time ripping and encoding, would you think it is important to back it up somehow with another drive or a tape drive or something?

I've started to rip the CDs, I've got about 75 out of 200 done, and I'm wondering what should be done to protect the time I have invested.

I've got alot of hard drive space across 4 or 5 drives so I'll probably just use one as a double (mirror) to one of the others. But I think maybe the best idea is a dds-4 tape drive. These are useful for lots of stuff, like archiving video too. only thing is a good one will run around \$600, but you can use 20-40GB tapes. The cost of the media is cheaper than DVD recordable formats, and I don't feel comfortable getting into that technology just yet.

15. ### Uchendu Nwachukwu Agent

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The simple and short answer: Figure about 100MB per CD (using LAME's --r3mix setting). Since most CDs actually work out to about 70 - 90MB, that'll leave signifcant space for expansion, especially if you have a huge CD collection.
As for backup, the ideal solution in my view would be to set up a RAID 1 (mirrorring) array with two removable hard drives. You'd need a RAID controller card, two removable HD bays, and of course two identical HDs. About \$500 should cover it, depending on the size of the HDs.
When/if you fill up a pair of drives, you can simply buy a new pair and put them in. They are also great for archiving (but not the best).

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Well, I wouldn't call mirroring ideal. RAID5 is more efficient when it comes to the amount of space lost. With mirroring you lose 50%, but with RAID5 you only lose one drive worth of space - regardless of how many drives you run with. So, with 5 drives, you've lost 20% and still have full redundancy.

But of course, RAID5 costs more money to begin with since you need at least 3 drives to set up an array, and the controller needs to be better than one that will do mirroring.

17. ### John_Bonner Supporting Actor

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Rob / Buzz / WoodyH,

Just out of curiousity, I understand the pros of putting your CD's onto your hard drive but why rip every song in your collection. Is this for archival purposes? I also have several hundred CD's but can't say I like every song on every album. I'd rip the songs I like best and even those "marginal" songs and probably save a couple of GBs of space. Just my thoughts...

18. ### Rob Gillespie Producer

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John, for me it just comes down to being a completist. If I'm going to do something, I do it in totality, not by half measures.
I have a Kenwood head unit in my car which plays MP3 files from CD-R. I have my whole CD collection stored on my system, so it's just a case of picking 8-10 albums, burning to CD and I'm off.

19. ### Hugh M Second Unit

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oops, didn't mean to hit a nerve..

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