Updated May 29th, 2003 12:38AM
| What is SHN? The purpose of the Shorten (SHN) format is not only to reduce the number of discs which have to be mailed or downloaded (6 instead of 10 for TT1, 8 instead of 14 for TT2), but more importantly to safeguard or "package" each music file in such a way that you can be 100% certain that what you have received is identical to the original. |
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People trust their standalone or computer-based CD-ROM or CD-RW drives to read and write CDs with no errors, especially at very high speeds. But I cannot count the number of times I have received CDs with pops, clicks, jumps, and entire sections missing due to errors in the reading or writing of CDs. For a time, there was a movement to ask everyone to record their CD-Rs slowly, at 4x or 2x, claiming that higher speeds were the cause of all the problems. Although reading and writing CDs at high speeds, especially on marginal equipment certainly does reduce the likelihood of producing perfect discs, speed alone is not the problem. So what do we do? Do we all copy our CDs at 1x or 2x, sitting there for 40-80 minutes watching a progress indicator creep across the screen on our high-speed CD recorders that we blew $200 on? There is another solution.  First, the original (or close to it) CDs must be read into a computer with maximum accuracy. The concert trading community uses a music CD reading program called Exact Audio Copy which is explained further down this page. Second, we "package" the audio into the SHN computer format. SHN is a lossless compression format, meaning that not one bit of sound quality is lost in the conversion. Think of it as "WinZip" for your music. Also, SHN packages contain an MD5 checksum which is a 'signature' that can be used to verify if the disc has been corrupted in any way.Just having the music in a data rather than audio format lets us benefit from the fact that: 2-3% of an audio CD is used for error checking. 17% of a data CD is used for error checking.  Third, each person who receives an SHN disc or download should always confirm the integrity of the SHN files by comparing them to the MD5 checksum files before they start making copies or producing regular audio CDs from them.I have heard people say "Maybe SHN is not ready for prime time?" SHN is widely used with great success on other Trees as people exchange concerts by different artists. I would imagine others had the same (or worse) issues when they started out, but once they got the hang of SHN, it has become a well-oiled machine. I'm hoping the same thing will happen with the Tangerine Trees. The alternative to SHN, simply trusting each set of discs as it makes its way in and out of 7-8 computers before it gets to the lowest branches, is unacceptable to me. I believe the problems we have had with SHN have been caused by trusting the discs we get and using marginal blank CD-Rs. |
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Getting Started Now that you've got your set of Tangerine Tree SHN discs in the mail, you've got a few choices before making copies (SHN or audio CD). Verify the discs you received before you start making copies!!
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Verifying received SHN Discs To verify that the SHN discs you've received are good, you will want to download a program called mkwACT. To check the SHNs that you've received (either on-disc or after reading them to your hard drive), double-click on each MD5 signature file on the disc. After you have checked each of the MD5 files, you can confidently use your CD recording software to make a duplicate of the SHN CD. I like to change a couple of the default Settings used by mkwACT, especially the notification results of each "test" or verification. I want to ALWAYS receive the results--even if all SHN files turn out Kosher. This setting is available under the Options menu of mkwACT (under File Options). I uncheck everything except Create subdirectories and Generate md5 checksums after compressing. |
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How to find all the parts of a Concert In order to minimize the number of discs required for each Tangerine Tree/Leaves set, sometimes, the SHNs for a single concert will be found on multiple discs. Fortunately, the SHN files all have an intricate naming convention which I will go into. If you look at the diagram on the left, you will see Volume 09, which is the Royal Albert Hall April 2nd, 1976 show. This is the first SHN disc where this music appears, so you can see "tadream1975-04-02.txt" which is a description file. In the folder below that, you'll see that this concert spans 2 discs, "tadream1975-04-02d1" (Disc 1) "tadream1975-04-02d2" (Disc 2) In the bottom folder, you'll see that we are looking at track 1 from disc 1 of this show: "tadream1975-04-02d1t01" (disc 1, track 1) Finally, you'll see an MD5 Checksum File. "tadream1975-04-02d1.md5" (MD5 Checksum File) An MD5 Checksum File is a signature which can be compared to the SHN files to see if anything has gone wrong. If errors have been introduced into the SHN file(s), a quick comparison of the MD5 signature will warn you of any problems! |
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Extracting SHNs to WAV When you are ready to make ordinary music CDs from SHN files, you will need to extract the SHN files to a standard audio format such as wave (WAV). If you installed mkwACT with the default settings, then you should be able to right-click on any SHN file and choose Decode to wav. To convert multiple SHN files to WAVs, start the mkwACT program and then drag each SHN file (or a group of SHNs) into waiting mkwACT program window and it will start decoding them. Be aware that most CD Recording software like CDRWin and Nero frustratingly assume that you want a 2 second "pregap" between each track/song. This is disastrous for concert recordings that should have seamless time indices. So remember to change the recording settings so that each track except to the first one has a 0 (zero) second pregap. In Nero, you can Select All, Ctrl-click the first track, then pull down the Edit menu to "Properties" to change this from 2 to 0. |
| Exact Audio Copy I cannot speak for standalone CD recorders, but in the computer world, there are dozens of music CD "ripper" programs out there for getting the music off a CD and onto your hard drive. It might be exciting that you can read a music CD in 4 minutes, but you are rolling the dice! All of these programs blindly rely on the Digital Audio Extraction (DAE) functionality of the CD-R/CD-ROM drive which can and will introduce errors galore! There is an exception. Designed for serious CD replication, I cannot recommend strongly enough a free "ripper" program called Exact Audio Copy. The first thing you'll notice about this program is that it does not read a CD in a speedy 3, 5 or even 10 minutes. It will often take 15-20 minutes to read even a brand new disc. The difference between Exact Audio Copy and virtually all the other CD reading software out there is that it tirelessly verifies the music as it is reading it. It uses any extended error checking info the drive can provide (some of the more recent CD-R/CD-RW drives have this) Then it actually listens to the music for pops, clicks, breaks in the frequencies, and disparities between the reported track length and what was actually read, and asks the CD-ROM drive to take another shot at reading it, up to 30 times per sample. Sometimes this will give you a false positive on an intentionally crackly track, but that is of small concern. An extreme example I have experienced was an Encore 77 CD which was extremely scratched. I had little hope, but I read it in using Exact Audio Copy. It took 6 hours(!!) to read the entire disc, but except for 3 minor audible flaws, the sound was perfect. |
 It is certainly your decision which CD-R discs you want your copies of the Tangerine Tree--and indeed any project--recorded onto. In these days of free-after-rebate or 15-20 cent blank CDs, I believe it is worth the extra pennies for premium CDs. Obviously these are my opinions and you might have different ones. I must strongly recommend against PNY, Verbatim Valuelifeplus, Memorex gold-top, and Maxell. I recently removed Verbatim Datalifeplus from my list of recommended CD-Rs due to issues with flaking and a high percentage of DOA blanks. Here are the discs I trust: Memorex silver-top 80min TDK Data CD-R 80 min Mitsui Taiyo-Yuden (they invented CD-R!) Imation As for which CD-Recorder to buy, HP/Philips/Sony are on my absolutely not list. You just can't go wrong with Plextor and they have gotten relatively inexpensive! |