source file: mills2.txt Date: Fri, 13 Oct 1995 20:41:40 -0700 Subject: 88CET #19: Timbral Considerations From: Gary Morrison <71670.2576@compuserve.com> Orchestrational considerations are something of a mixed bag; some traditional orchestrational notions apply equally well to 88CET, but others are better rethought a bit. Some need to be rethought for concrete, physical reasons, and others need to change strictly for aesthetic reasons. As for the aesthetic reasons, some timbres just aren't all that exciting in 88CET. Classical guitar sounds I have found to be less interesting than harpsichord for example. That was sad to accept for me, having played classical guitar for many years. Piano sounds about as good in 88CET as in any tuning. Even though I've used flute sounds successfully for variety in my 88CET compositions, there are better instrument sounds to use for 88CET. Clarinets and brass instruments probably work best of all. Saxophones and bowed strings generally work fairly well too, although not as spectacularly well as brasses. There is an amusing footnote to these instrument choices: Some of the instruments that sound best in 88CET cannot be constructed physically in 88CET tuning. Notably, winds use the lower-harmonic vibrational modes to extend their range. That is harmonics like single- and double-octaves and twelfths which lie outside the 88CET system. It's far more difficult to get a tube to "overblow" in the seventh- and eleventh-harmonic modes. On the other hand, I've given some thought to the purely-cylindrical flute's tendency to overblow to a flat octave, to create an 88CET flute as an instrument that play 13 steps per quarter-tone-flat-octave. In the realm of the concrete physical issues are organ timbres. Does adding, for example, a four-foot flute rank to an eight-foot diapason rank in a nonoctave tuning produce a richer timbre, or just a false note (the octave) that doesn't exist in the tuning system? Best I can tell, the answer is more likely that it'll sound like a false note not in the tuning. With such strong power-of-two harmonics, you almost invariably create those dreadful false perfect consonances. Instrument timbres with modest-to-normal levels of octave-harmonics don't pose any such concerns though. Of course the case of a timbre's partials creating harmonies not present in the tuning system is certainly not unique to nonoctave tunings. The seventh and eleventh harmonics don't fit into the usual 12TET system, and the fifth harmonic is not represented very accurately. The big difference is that we're creating false consonances with very basic, and thus frequently louder, harmonics than before. It is therefore a bigger concern in a non-octave tuning than in an octave-based tuning, but is a concern in either. This of course doesn't rule out writing for individual ranks, but the lack of the free-form doubling damages the organistic quality of the music. In the vein of less basic physical concerns, certain instruments' overtone structures seem to lend themselves to certain chords over others, as is the case in most any tuning. I haven't studied this topic extensively, but I have noticed an especially strong example of this: The 6:7:10 chord seems more discordant than the 6:7:9 subminor triad on timbres with weak even harmonics, whereas the reverse seems to be true on timbres where even harmonics are about the same strength as odd. I'm sure that there are many other examples of this sort of phenomenon, and those wishing to investigate it may want to start with this example. Received: from eartha.mills.edu [144.91.3.20] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Sat, 14 Oct 1995 08:35 +0100 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id XAA15368; Fri, 13 Oct 1995 23:35:19 -0700 Date: Fri, 13 Oct 1995 23:35:19 -0700 Message-Id: <951014063255_71670.2576_HHB5-8@CompuServe.COM> Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu