How do I find the key? If you got a keyboard or a piano that is probably the best equipment you can use, but using some kind of software that will emulate a music keyboard will work just fine, like Sonic Foundry`s Sound Forge (choose the keyboard from the menu). Use sounds without any vibrato or other strange effects on them, a simple piano sound works best for me. You don't need to be a skilled keyboard player to find the key, you don't even have to know how to to play the keyboard at all. As long as you have a good ear that should be enough. Keyboard/piano lessons are higly recomended though. When you are trying to find the root key, play one note at the time. The note that blends in with the song, almost disappears in the sound picture is probably the root key. After you have found your first root key suspect try to play the sub dominant(5 halvsteps +/-) and dominant key(7 halvsteps +/-). See the Harmonic Chart to find matches. Remember there are 12 notes in a octave. C is 1 Db is 2 etc etc. I.e. You have found out that the nearest to the root key is C, try playing F or G. Do they sound more right? If you are 100% certain that you have found the root key try now to play a chord, major chord is root key+ 4+3 halvsteps and minor chord is root key +3+4 halvsteps. Try to listen to the mood of the song, is it major or minor? Some songs just have a note and therefore very difficult to determine a chord. If you can`t get the hang of this, ask a musician for help or use a software key recognition software. "Mixed in Key" is highly recommended. Remember one thing: on the Technics SL1200 you have an increase\disincrease of 8%, which means that the key changes when use the pitch control. 6% pitch increase/disincrease is the same as one halfsteps. (at 0 pitch the key is C and at +6% it is Db). On a standard record player if you change your rpm from 33 rpm to 45 rpm you then will jump 5 halvsteps up, and vice versa. C will then be F. PS! This may vary from deck to deck, but in theory a pitchshift in one halfstep (semitone) will be a beat difference of about 6% bpm of original tempo. Use tempocalc to calculate the beat difference, download it from here. Auto detect notes by software. One of the most popular software for finding the key is my friend DJ Yakov's "Mixed in Key" program. This program does it all, find the key with a accuracy of 95%, calculate the BPM and write back to the mp3 file as id3 tag. This program uses the Zplane's kickass key detection algorithm. Read more about this wonderful product at www.mixedinkey.com There is also a product called Mixmeister Pro that is a compelte dj mix package. Exactly how realiable the key detection is hard to say, but it looks like it only detects minor keys. Hopefully they will fix this bug in a future upgrade. And there is also Mixshare's Rapid evolution, but I find the userinterface and the key detection algorithm is not as good as "Mixed In Key", check it out at www.mixshare.com. If you want to take it one step further and really see what is going on in a song, or prefably a loop check out Celemony's Melodyne. Read more here: www.mixedinkey.com www.mixmeister.com www.mixshare.com www.zplane.de www.celemony.com