See Screen Layout for a picture of an example spectrum, and see Spectrum for a brief discussion of its meaning. Also see Keyboard for instructions on how to scroll the piano keyboard graphic, so as to choose which part (higher/lower) of the spectrum to bring into view.
Any waveform, no matter how complex, can be regarded as the combination of a number of pure sine wave tones. Transcribe! calculates the spectrum graph by a "discrete fourier transform" which can take any waveform and "separate out" the sine wave tones which are present in it, determining the pitch and amplitude of each.
The spectrum for a sound which is a pure sine wave would consist of a single narrow spike. Real musical instruments do typically produce a strong sine wave component at the note being played, and it is this spike in the spectrum that shows us the note being played. However, real instruments also produce a lot of other stuff which can confuse the picture, especially when several instruments are playing.
Transcribe! has a feature to help you identify harmonics. If you click with the mouse on the spectrum display Transcribe! displays a series of vertical lines extending four octaves either side of the clicked point. Those above the clicked point indicate other notes which might be harmonics of the point you clicked, while those below the clicked point indicate notes of which the clicked point might be a harmonic. Naturally, the pattern of lines is symmetrical either side of the clicked point. I find this feature can sometimes be surprisingly useful. I have come across heavily distorted single-note guitar sounds where the pitch is clear to the ear but the note that the ear hears does not show up at all clearly on the spectrum. By clicking on the spectrum and moving the mouse around, you can get a perfect fit on the whole harmonic series, which reveals the true pitch of the note even though there is no peak in the spectrum there (at the clicked point). What is happening is that the guitar distortion generates lots of harmonics but has lost - perhaps by subsequent filtering - most of the fundamental. When we hear this, the ear is clever enough to recognise the harmonic series and tell us what note is really being played.
The first step in getting the cleanest picture you can is to select as large a segment as possible, during which the chord you want remains constant. Do not expand the selection to include any part of the chord before or after as this will really confuse things. The easiest way to get the selection right is to set Transcribe! playing it round and round (turn on "loop" playback mode) while you adjust the selection length with the mouse. You can adjust one end of an existing selection by holding down the <shift> key while you press the mouse button near one end of the current selection, or with the keyboard.
Note that the maximum length of selection for spectrum is one second : if you select more than this then the spectrum you get will be of only the first second of the selection.
If the main peaks in the spectrum are consistently mis-aligned with the note-centre pitches (the vertical black and white lines rising from the keyboard graphic) then it might be that you have not adjusted the piece to concert pitch (A = 440Hz). Use the Tuning command (Options menu) to adjust until the alignment is better. Of course, if some peaks are aligned while others are not then this could mean that the musicians are playing out of tune with one another, and you'll just have to live with it. Bear in mind that the tuning of a piece can vary from moment to moment if it's been recorded on wonky old equipment.
Usually the messiest part of a complicated spectrum is the upper part since this is where harmonics proliferate. However if you listen by ear to the segment, in context, then it's often quite easy to make a judgement about what the highest note being played really is (play notes by buttoning the keyboard graphic, to locate the spike in the spectrum which corresponds to it). You can then dismiss everything above this point as irrelevant. Scroll the keyboard so this stuff disappears off the right of the view and doesn't distract you.
If the spectrum shows more notes than you think should be present, then is it possible that some of the notes are actually changing during the segment you have selected? Listen carefully. Try making the selection shorter at one end or the other and see if some of the notes in the spectrum disappear. You can adjust one end of a selection by holding down the shift key first, and then mouse-click near the end you want to adjust, or with the keyboard.
If the Sound file you are working on is stereo then try the Stereo Mix command. You may be able to find a mix which emphasises the instruments you want to transcribe while reducing the volume of distracting sounds.
Use the "Print" command to print out the spectrum. Then look for other occurrences of what you suspect may be the same chord, and look at their spectra too. You can also use the New Window followed by Tile commands to view spectra of two chords at the same time.
You have to make a judgement about which peaks are notes being played, which are harmonics, and which are just rubbish. You must use your ear and your brain, try playing the various possible chords on your own piano or whatever and see what sounds right. Of course, this is exactly what you would be doing if you didn't have Transcribe!. Transcribe! simply gives you an additional source of information on the sounds, to be added to what your ear tells you. This brings us back to the point mentioned in the Introduction that Transcribe! should be seen as an assistant, and cannot do the whole job for you. To some extent the peaks in the spectrum graph should be seen merely as suggestions.
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