Perhaps sound examples of the sounds as they should sound and as they do sound would be good for troubleshooting, to avoid some speculations. Usually the method of elimination will lead to the solution. Some speculations: This happens even, if you play the Waldorf only, not live, but by a sequencer? - Issues could be caused by to much data for to less MIDI interfaces. - Inaudible short latency and jitter, if you try to play the instrument live, by this MIDI chain, e.g. you don't hear delay, but portamento is sensitive to the way you play the synth, IOW even inaudible latency and inaudible jitter, regarding to the time length, can become audible, because the flow, how you play notes for filters that follow e.g. portamento and legato, is different. Another issue might be, that your masterkeyboard sends different types of note off events, than the ALSA sequencer does send. Note off vs Note on velocity 0. I suspect something similar as the note off issue, perhaps after touch vs enabled or filtered etc., or some MIDI data filter does filter control data. Very common are filters that protect against to much pitch wheel and modulation wheel data. Instead of 15 different controller values during a 1/8 note, the software might send only 4 different values. And again, it's very common to e.g. filter after touch messages completely. The MIDI connectors could also cause issues. You might use the same MIDI cable, but you use different MIDI sockets. Assumed you once used a "real" MIDI cable, where the male connectors have thicker connector pins than a HiFi DIN connector has got and you now connect to the female socket a male jack with thinner pins, vibrations when playing the instrument on a wood flour could cause unclean transmitted MIDI signals. I can continue the speculations, as we say in Germany, "man hat schon Pferde vor der Apotheke kotzen gesehen", Pferde können aber nicht kotzen, IOW what's impossible by science, is possible in real live. I e.g. experienced that the Roland MT-32's HiHat gets a bad timing, if you play to many instruments, on different MIDI channels, with to much data. If I play the same with the Yamaha TG33, also just one MIDI in, there might be no issue for the HiHat. Such effects can be avoided, if a sequencer has got no jitter and you minimal (1 or 2 ticks at a high resolution) move some MIDI on events. However, usually my experiences with MIDI (since MIDI was invented until today) only lead to noise on Linux mailing lists ;). Btw. are you sure that the Waldorf or anything else isn't broken and it's just by random, that you experienced issues only, when you connect to the PC and when you play some sounds? When building audio equipment people I know and myself experienced "random" very often as something that lead to astray.

On 12/15/2012 12:08 PM, Julien Claassen wrote: It was either Gremlins.... or you forgot to properly adjust the Johnson Rods.

The music gear are the Gremlins. Sunlight? Water? Dinner? UV light can damage studio equipment, at least the grey computer cases become bad coloured, EPROMS get cleared, plastic and glue corrode. Hints regarding moisture are written in every audio gear manual. Tzatziki inside the Alps faders is also unfavourable.

On 12/15/2012 01:01 PM, Folderol wrote: I try to stay away from the 360 Degree Phase Shifters. They introduce too much latency, and it varies with frequency!!! -- --- My bands, CD projects, music, news, and pictures: http://www.lateralforce.com My blog, with commentary on a variety of things, including audio, mixing, equipment, etc, is at: http://audioandmore.wordpress.com Staat heißt das kälteste aller kalten Ungeheuer. Kalt lügt es auch; und diese Lüge kriecht aus seinem Munde: 'Ich, der Staat, bin das Volk.' - [Friedrich Nietzsche]

On Sat, 2012-12-15 at 18:08 +0100, Julien Claassen wrote: Very likely, while MIDI connectors usually aren't that bad incompatible, as 6.3 jacks often are. It's less likely corrosion, I often experienced that all kinds of jacks and sockets don't fit to each other. For USB connectors I sometimes had to remove a little bit of the isolation, because they couldn't be plugged in, regarding to too much isolation. For the 6.3 jacks here are different shapes, some are completely unusable. And as I mentioned before, the thickness of the MIDI connector pins can vary, but this most seldom really does cause issues. Resume: It was a random issue, voodoo, most of the times the cause for trouble in maintained studios. The Waldorf is a baby ;), since it can't be born earlier than 1989. OT: I wonder if should crimp my telephone's cables for the thousands time or if I should through away those crimp connectors and solder the cables directly to the telephone and handset. Good connector: Großtuchel In the German Wiki is a picture that does show a 2,-€ coin and a Großtuchel, because Großtuchel is very clumsy. Similar diameter as the coin, for 3 contacts only. But you can screw together Großtuchel and it has got knifes that clean the contacts, when you connect them.