sandell@ferret.Berkeley.EDU (Greg Sandell) (04/10/90)
Recently I purchased four of the compact disks in the McGill University Master Samples series. For those of you who don't know them, they include an individual recording of every instrument of the orchestra playing every note in its available range. `Non-clasical' sounds are available as well, such as Rock drums and guitar chords. I am also thinking of buying discs from the Pro Sonus series. From what I know of them, they have similar `classical' sounds, although they have recorded only every fourth note of the available scale for each instrument. They are obviously targeted more exclusively to the needs of Digital Sampler keyboard users, rather than those with research interests. Has anybody else used any of the ProSonus disks? I would be interested in hearing your evaluation of them. I have been doing spectral analyses of entire instruments in the McGill series, and, having seen tremendous note-to-note differences, am convinced that a strategy of recording only every fourth note is a real error. As an example, when english horn goes from F4 to F#4 (sounding pitches) there is dramatic change in fingering from all keys closed to all keys open (roughly). This corresponds to a dramatic change in spectral envelope between these two tones. Clearly such timbral discontinuities are critical to the essential character of the instrument. I am not a Sampling Keyboard user, but it strikes me that just because the current memory capacities of these devices only allow the sampling of every fourth note, it is extremely shortsighted to go through the trouble of recording such tones at great expense and releasing them on CDs when it's only a matter of time before memory is so cheap that the current limitations of Sampling Keyboards will be a joke. Here are some brief evaluations of some of the instruments. As you can see, the playing quality is not consistent; I think that this is a major drawback in the McGill series. I hear that the current issue of CMJ contains a review of the McGill tones, but I haven't seen it yet. 1. Excellent tone quality and evenness of tone productions in the performances of: violin bowed vibrato double bass bowed flute non-vibrato English Horn tenor trombone tuba 2. Less satisfactory tone quality or evenness: viola non-vibrato (very scratchy) Bassoon (weak in mid-high registers; very high notes omitted) french horn (the user's manual does not describe the mike placement of these tones; I suspect that the mike was place right by the bell, which may not effectively capture the sound we usually hear in this instrument, since the bells do not face the listener.) Bb clarinet (very `hooty') 3. Poor tone quality, very uneven All trumpets (most notes not even recognizable as a trumpet) 4. E2 missing from tuba series; A#1 missing from 9' grand piano, right pedal depressed (volume 9) 5. celesta recording is very noisy (volume 9) **************************************************************** * Greg Sandell (sandell@ils.nwu.edu) * * Institute for the Learning Sciences, Northwestern University * ****************************************************************
jimh@ultra.com (Jim Hurley) (04/12/90)
sandell@ferret.Berkeley.EDU (Greg Sandell) writes: >Recently I purchased four of the compact disks in the McGill University >Master Samples series. [ deleted ] >I have been doing spectral analyses of entire instruments in the >McGill series, and, having seen tremendous note-to-note differences, >am convinced that a strategy of recording only every fourth note >is a real error. [deleted] > I am not a Sampling Keyboard >user, but it strikes me that just because the current memory >capacities of these devices only allow the sampling of every fourth >note, it is extremely shortsighted to go through the trouble of >recording such tones at great expense and releasing them on CDs when >it's only a matter of time before memory is so cheap that the current >limitations of Sampling Keyboards will be a joke. [deleted] >**************************************************************** >* Greg Sandell (sandell@ils.nwu.edu) * >* Institute for the Learning Sciences, Northwestern University * >**************************************************************** You haven't gotten any responses to this yet so I'll take a stab. I had a fairly violent reaction to this posting because of my own synthesis bias and I'm by no means a sampler expert - never having used one. But that won't stop me from expressing some opinions. I'll relate my bias as I go. About every fourth note... I think most samplers allow you to place a sample over any range of keys, down to a single key, and it will pitch-shift within that range. There may be individual limitations due to design or memory but there's nothing intrinsic in a sampler to prevent this. I suppose that every fourth note was just a concession to space or time constraints on the CD or the performers. I could be wrong about this because as I said I have never used a sampler, but I understand the technical architecture. In the following discussion I'll use a violin instrument for the sake of a concrete example, other instruments share some of this and perhaps have other topics of import. Firstly: where do you stop? Are the notes tuned in equal-temperament? If so, won't your sampler's chamber music sound odd? I thought most good chamber players use just or Pythagorean tunings or tend in that direction. And what if you want microtonal intervals? In short, just what interval do you want? Second point: what instrument do you want sampled and how many? Do you want a Stradivarius and a Guarnerius violin sample? Third point: how was the sample made? Radiation patterns around the violin are difficult to simulate from a single microphone source or even a stereo pair. Depending on where the mic(s) are you may see spectral changes more radical on a single note from mic location-to-location than you see from note-to-note at a fixed location. Fourth point: this relates to the final sound from a sampler. The original sample will probably be neutral, void of as much artistic modulation as possible, since it is the basic source in the synth and you will want to impose performance modulations from the synth controls. In other words, the vibrato will come from, say, a mod wheel controlling an LFO which modulates various internal processors in the synth. I don't think you want the sample to have any vibrato at all or you're stuck with this at the source level and will get peculiar results if you want to change it (or if you want to play, say, a Bartok piece that requires no vibrato). Bowing effects will also have to be programmed somehow and you don't want to have any strong bowing in the original sample. By the time you reduce the sample to this simple basic source, it hardly seems to matter much how many notes were originally sampled, as long as you get the main registers correct. Your real problem will be to put some life into that sound within the limitations of the sampler. Fifth point: here's where my own bias comes in. Why do you want to sample a live instrument anyway? If it's to imitate it as much as possible get a mellotron;-). If it's just a starting point to an original sound then you're talking my language and the number of samples is not such a problem. I happen to feel that there's many wonderful and unique sounds out there that are the rightful domain of electronic instruments. We should spend our time looking for these and learning how to be skillful in their execution. Imitation can be an extremely valuable lesson in synthesis, but it is a tool and not an end result. Of course this is idealistic and there are practical concessions to make to those who want to play others' compositions and don't have the resources of a symphony at their disposal (this probably includes all of us:-). I'm addressing this note from the point of view of a composer, not a performer. Some other points. I don't think that memory limitations will ever be the main problem here. I think it will be the ability to to translate human gestures into meaningful modulation processes. Let's look at the memory requirements, however, and let's be a bit extravagant in our hypothetical design. Let's assume that we want better-than-CD quality stereo output over the 128 note MIDI range from our instrument and let's see how much memory that will consume per instrument. In practice there may be multiple samples cross-faded or otherwise mixed to get a real instrument, but that will just be a multiplier in the final number. Assumptions: 100KHz sampling, 32 bit samples (32-bits is a nice memory width with current micros), 128 notes, 2 channels, 10 second sample time (pick your time here); the memory requirements are then 100000 samples/sec/note/channel * 10 secs * 128 notes * 32 bits/sample * 2 channels = 8 192 000 000 bits or approximately 2**33 bits. Current memory chips are now 4Meg (is that right?, it's been a while since I looked at these) and the size is doubling or squaring every few years. So in a few years we can store about one of these instruments in a memory chip. Of course, storage of the whole repertoire of instruments will probably be an external devices, but we'll still need to store a few instruments in the main sound memory. And undoubtedly there will be storage technology breakthroughs that we can't imagine in the next decade. -- Jim Hurley --> jimh@ultra.com ...!ames!ultra!jimh (408) 922-0100 Ultra Network Technologies / 101 Daggett Drive / San Jose CA 95134
scott@bbxsda.UUCP (Scott Amspoker) (04/12/90)
Greg Sandell writes: >[dissapointed with sample CDs] > I am not a Sampling Keyboard >user, but it strikes me that just because the current memory >capacities of these devices only allow the sampling of every fourth >note, it is extremely shortsighted to go through the trouble of >recording such tones at great expense and releasing them on CDs when >it's only a matter of time before memory is so cheap that the current >limitations of Sampling Keyboards will be a joke. Jim Hurley writes: >About every fourth note... >I think most samplers allow you to place a sample over any range >of keys, down to a single key, and it will pitch-shift within that >range. That is true for any sampler I've used in recent years. > I suppose >that every fourth note was just a concession to space or time constraints >on the CD or the performers. I have one of those CD sample libraries. They have grand piano samples for every note. However, most instrument samples are given for every 3rd or 4th note. This is a valid compromise since most of the time you can create an *almost* seamless transition from on sample to the next. If adjacent samples are that distinct from each other then the sample library itself was poorly created. I've heard very successful string and brass implementations with one sample every 4th (or 5th) note. Vocal samples, however, are fussier and require shorter intervals. >Firstly: where do you stop? Are the notes tuned in equal-temperament? >If so, won't your sampler's chamber music sound odd? I thought most >good chamber players use just or Pythagorean tunings or tend in that >direction. And what if you want microtonal intervals? In short, >just what interval do you want? Some samplers allow different tunings, this is not hard to do. >Second point: what instrument do you want sampled and how many? Do >you want a Stradivarius and a Guarnerius violin sample? >Fourth point: this relates to the final sound from a sampler. The >original sample will probably be neutral, void of as much artistic >modulation as possible, since it is the basic source in the synth >and you will want to impose performance modulations from the >synth controls. This is well understood by sampler owners. Samples should be as vanilla as possible (with exceptions) so you can add your own vibrato and articulation. The end result might not be *exactly* like the original instrument but can be musically pleasing. >Fifth point: here's where my own bias comes in. Why do you want to >sample a live instrument anyway? If it's to imitate it as much as possible >get a mellotron;-). Why a mellotron? The modern sampler can be though of as a digital mellotron. (Granted, all those tapes can contain more sound the the typical modern sampler, but they're slow). I agree with Mr. Hurley that if perfect imitation is the goal one might be wasting one's time with a sampler. A sampler is good for capturing the essence of an instrument allowing the user to do musically useful things with it. However, there are also many other interesting uses for a sampler. -- Scott Amspoker Basis International, Albuquerque, NM (505) 345-5232 unmvax.cs.unm.edu!bbx!bbxsda!scott
sandell@ferret.Berkeley.EDU (Greg Sandell) (04/13/90)
> Jim Hurley writes: > > I suppose > >that every fourth note was just a concession to space or time constraints > >on the CD or the performers. > > This is a valid compromise since most of the time > you can create an *almost* seamless transition from on sample to the > next. If adjacent samples are that distinct from each other then > the sample library itself was poorly created. The question is, how much is `too distinct'? As I pointed out, there are many changes in character and spectral quality in musical instruments from one note to the next that are a natural outcome of acoustical properties (that arise from mechanical and manufacturing problems). Starting with D4 on the Bb clarinet...*all* Bb clarinets...the notes get increasingly thin, and the notes F4-G#4 are so thin that this group of notes has a name ("throat register"). (I am referring to sounding rather than written pitches, by the way.) Then at A4 there is a dramatic increase in fullness, and this is referred to as the break between the chalumeau (lower register) and the clarino (higher register). This may be one of the more dramatic discontinuities in the family of orchestral instruments, but all instruments have them to one degree or another. The point is, that these bugs have been turned into features by composers for a long time, and it's part of the character of the instrument. > Samples should be > as vanilla as possible (with exceptions) so you can add your own > vibrato and articulation. The end result might not be *exactly* > like the original instrument but can be musically pleasing. I guess sampler users want to `cue' certain sounds..."Oh, that's a clarinet". There's a world of difference between that and the activities of people at IRCAM, CCRMA, CNMAT, and so on, with their instrument modeling projects, where the idea is to make as authentic-sounding a simulation as possible. But I think that sampler users and manufacturers ought to recognize how short-lived the effectiveness of the `cueing' approach is in synthesis techniques. When FM first came out, and for a few years after the DX-7 came out, the brass sounds were real enough that a listener would say, "oh, that's a trumpet or trombone or french horn or whatever." But now it's just a dated, phony-sounding imitation brass sound, and people expect something better. Whether we know it or not, we are all pupils in a massive ear-training project. Each time a new synthesis technique comes out, it has a lifetime of its own, governed by how long users are willing to accept it as being lifelike and realistic...and the outcome is that our ears are getting more sophisticated and demanding. Please don't flame me for concentrating on the re-creation of natural sounds...that's how this discussion began. Many of the issues of what makes a imitation of an acoustic instrument lifelike and pleasing is directly applicable to what makes a newly-created sound interesting. Greg Sandell **************************************************************** * Greg Sandell (sandell@ils.nwu.edu) * * Institute for the Learning Sciences, Northwestern University * ****************************************************************