I have started to work on the rendition of the 2nd movement of Gustav Mahler's Symphony #1. This time I applied a new method: I first played "live" on piano the whole movement, with excerpts from the part, in order to get the desired tempo that I felt would be right. I also hoped that by this method I would be able to incorporate those slight tempo variations within a theme, a motif, a phrase, and within a bar. So after the recording was completed (it took me about 3 weeks to get this initial recording done, because I often stopped and repeated, as I felt the tempo was not right), I recorded another track, which just had the beat indicators in it. I listened to my recording and just hit a key on the keyboard, linked to a percussion instrument. This track was then the reference track for the tempo, and I used the SONAR tool "Fit to Improvisation" to create the tempo map which creates a list of tempo values at every quarter note. When looking at this tempo map, I saw very interesting artefacts: there appeared some patterns in the tempo within the bars, which were not consistent throughout the piece. In some cases there was a slow-fast-slow bar, and sometimes there was a fast-slow-fast bar. I was not able to determine first if that was just through my own inaccurate playing or tempo mapping, or if there was actually some musical principle behind this. But I noticed overall that I had started quite slow, much less than was noted in the score (score: 3/4=66, mine: 3/4=50), but then the tempo accelerated throughout the movement. Not very good actually - there was no good reason for that other than I had been carried away... I now can admire the conductors' ability to keep the tempo constant.
After having the tempo map I began recording the actual music instrumental tracks. And here it became apparent that this pre-recorded tempo map was pretty useless in many cases: the tempo variations within a bar prevented me to get a constant beat where the rhythm had to be exact and quantised. This was important for instruments which established the base rhythm, for example in percussion parts, or when a set of eighth notes were to be played: these need to be exactly quantised in many cases, otherwise it sounds uneven, as if the player cannot play properly. The varying tempo that I had incorporated into my live recording, came from an interpretation of various instrumental parts which could overlay their own more "free" (rubato) voice onto that fixed and constant tempo. Now, in order to achieve this properly I had to abandon the original tempo variations, and I flattened the tempo map to mostly constant segments. Then I recorded each instrument and applied a slightly different treatment of the tempo: the important rhythm-establishing parts are quantised, whereas other parts I played the instruments freely, not exactly observing the beat times. This added a bit or realistic and more musical flow to the piece. But there I encountered the difficulty that the audio lag (due to buffer requirements) was about 30 ms (this was the lag between me pressing a note on the keyboard and then hearing it). So it was almost impossible to create an appropriate consonant accompaniment with already existing tracks in live recording, as my playing was recorded trailing behind. I could shift this after the recording, but during the play I did not really get the right acoustic feedback from my own playing; therefore I was not able to properly play the instrument tracks live but had to do a lot of manipulation and correction afterwards. I often ended up quantising whole segments, so that they matched the existing rhythm.
What might be done next time: I could set the buffer to a low value, for fast response and short lag, and then record only track by track, muting the other instruments, and pretending I would play a solo instrument. This would prevent the overload of the buffer (which occurred several times while I had 4 ARIA VST instances for all the instruments), but it would also prevent me to hear the other instruments while playing "solo": in the end the coherence may not be very good... I mayjust have to try it out to see if this is feasible.
In the meantime I reached already marker 13 (about 3 minutes) in the 2nd movement of this Symphony, with all instruments so far. It sounds a bit "tinny", more like chamber music, because I did nothing to add more "lushness". But this has also an advantage: the instrumental voices come out quite clearly, more clearly than in the traditional orchestra recordings I know. And someone had made already the same observation in the 3rd movement which I had posted a few weeks ago: the GPO samples as I have applied them do have a chamber-orchestra feel to them. I might have to double the strings and layer them with more players, to populate them and create a kind of "wall of sound" :) .
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