[sdiy] stringfilter (NEW INFO, NEW DEMOS !!!)

[Dino Leone]

Kenneth,

Just amazing those samples! Unbelievable!
  You know, you're making it a lot worse, my obsession and desire for 
such a stringfilter!! ;-)

Could we kindly ask you to go a bit more into details regarding the 
peaks and notches per octave? What are the exact numbers?

>  The best overall sound was alternating
>between 2 and 3 semitones for about the first 24 filters and then
>compressing down to 2 semitone spacing higher up.

Would that mean you make a peak at, say, C4, then a notch at D#4, 
another peak at F#4 and so on?


Are these the same numbers you used to generate the filter plot?
  How steep would the filterbands need to be? How big a Q? What's the 
"height" (in dB) of the peaks and notches?

Let me thank you again for those wonderful examples! They're simply 
breathtaking!

With Best Wishes,

Dino





>Jeurgen Haible writes:
>
>>>(Seriously: Ken Elhardt's string sounds are more convincing than my demos,
>and he used a handful of readily available FX boxes. Maybe he likes to talk
>about that)<<
>
>Hello JH.  I'm weeks behind on catching up on e-mail and posts so I'm just
>seeing this now. I realize I probably appear as if ignoring people but I'm
>just busy and really tired of the internet in general. I'll be catching up
>in a few days I hope, but I can tell you everything you need to know about
>string filtering and have a few new mp3 demos of my Nord 40 bank string
>filter in action.
>
>Too time consuming to cut and paste questions, I'll just answer them. Using
>equalizers for the job? They don't work. I also have that Behringer 24 band
>feedback surpressor. The sound will still sound synthetic, just filtered
>differently. No EQ has enough bands anyway. You need about 4 to 6 peaks and
>4 to 6 nothches per octave. A 31 band EQ only has 3 bands per octave, which
>only allows 1 peak and 2 notches or vice versa. Nor are they as steep and
>drastic as needed. JH could have mentioned some of the stuff I use as it's
>no secret, such as delay lines and phase shifters as comb filters. But I'm
>trying to get away from them because I have no control over how the peaks
>and notches are placed within something like a 40 stage phaser. And the
>metalic sound that delay lines create makes me have to use many in parallel
>to randomize the frequency response, and again I have little control over
>where those peaks are.
>
>I've actually done some high count multiband filtering on my Nord before.
>One demo I put up is the following showing the effect on an the unprocessed
>sound. Actually it's part multiband filterbank and phasershifter. I don't
>think something like the Moog string filter gives such a dramatic change to
>the sound.
>
>Filesize 200,622 bytes:
>
>http://home.att.net/~elhardt3/String_Filtering_motm.mp3
>
>As for my latest experiments below, I'm using my Nord Modular as sound
>source and to also process its own sound (I'm plugging the output of the
>Nord back into itself to process itself since I need the power of three DSPs
>just for the filter bank). I've tried many different configurations, such as
>6 bands per octave (every other semitone), 4 per octave, alternating
>spacing, random spacing, and so on. The best overall sound was alternating
>between 2 and 3 semitones for about the first 24 filters and then
>compressing down to 2 semitone spacing higher up. This produced the most
>wood-like tone, while not sounding too hollow, too synthetic, or all kinds
>of other problems I've come across. I'm then running that through a
>Behringer 31 band True Curve EQ to shape the overall sound for a more
>refined sound.
>
>Also the source sound you create to run through the filter bank is
>important. Just using a sawtooth oscillator with vibrato is too organ-like.
>I'm using several delay lines slowly sweeping around kind of as subtle
>choruses (also used this on my older string sounds), and they act as
>harmonics animators. If you've ever looped a single cycle of an acoustic
>instrument, it just sounds like an electronic tone because there is no
>motion. This also makes the vibrato sound sweeter and more string-like. You
>also want if possible, randomization of note pitch as fretless violin notes
>are always somewhat out of tune. You need human-like vibrato, changing in
>speed and depth. You need control of the string loudness and tone after the
>key is pressed so you can phrase it the way a string player would. I'm also
>using a Nord waveshaper module that adds some high freq harmonics for a
>brighter more scratchy sound which really helps bring out the buzzy top end
>of the cello, and I can modulate it if I want bownoise. If you want to play
>fast notes, you'll want some kind of bow slipping/scraping sound on the
>attack. And when I move my string source sound to Reaktor, I'll add the
>little portamento slides that really help (can't get to sound real on the
>Nord for some reason). In other words you have to really losen up and get an
>animated sound. Organ type sound in, organ type sound out.
>
>Filter plot of white noise running through my string filter:
>
>http://home.att.net/~elhardt4/String_Filter_Plot.jpg
>
>(Note that these demos should be heard through good quality highly detailed
>headphones to hear all the subtleties. I'm often shocked by how the
>beautiful tone and highend detail can disappear when played through other
>means.)
>
>
>
>Here are some new demos. This one alternates between my warm and fuzzy
>newage Nord violin and the real one in this Ackerman recording. I had to
>splice in solo guitar parts from the beginning of the piece, thus some
>obvious sudden edits. The timbre of the two is quite close just using my
>default filterbank band placement, so much so that with just a little effort
>in playing/phrasing and timbre adjustment I could probably replace the real
>violin in the entire piece and few would notice the change. Following is the
>timing of what is real vs Nord in the recording. Also threw in a Nord cello
>toward the end, really showing off the wood-like quality of the filterbank
>as the virtual bow scrapes across the last cello note.
>
>0:00 to 0:22 Nord
>
>22:00 to 0:38 Real
>
>39:00 to 0:58 Nord
>
>1:00 to 1:16 Real & Nord playing together
>
>1:12 Nord cello enters, all Nord through to the end
>
>Filesize 1,801,370 bytes:
>
>http://home.att.net/~elhardt4/String_Filter_Violin_Compare.mp3
>
>
>
>Here is a snippet from the Brahms violin/cello concerto. First take is with
>the real cello, second take is the Nord. Because my bands aren't in same
>places as the real thing there is a timbral difference (if I can correct,
>will be a near perfect match), but in the low end you will see that the
>cello-like characteristics of the Nord sound almost every bit as much like a
>cello as the real one, just with a different body timbre. Needs more work in
>the higher range to get that sad/whiney/stringy cello type sound.
>
>Filesize 541,641 bytes:
>
>http://home.att.net/~elhardt4/String_Filter_Cello_Compare.mp3
>
>
>
>One pitfall that I've encountered is when using the same string filter for a
>ll the instruments in an ensemble. I did one recording I didn't even place
>online because the entire orchestra sounded like it was playing through a
>tin can even though the individual instruments sounded pretty good by
>themselves. When I thought about it I realized that they were all
>emphasizing each other. Where as in a real orchestra, different instruments
>have different frequency responses and they smooth and average each other
>out. This is just one more reason to do it digitally where you can change
>filter settings unlike a fixed analog filterbank. None-the-less I tried to
>do a number of things differently to minimize that bad effect in my
>following Bach performance of a small up-close chamber group (with sampled
>harpsichord). Still it's a quite resonance sounding and badly distorts and
>sounds like total crap in many other ways through computer sound systems.
>Needs to be played through something that can handle severe resonances
>popping out all over the place, such as quality headphones. Even there,
>there were some problems, such as the popular Sony MDR-7506 which sounded
>ear-piercingly nasal in the 2K to 4K range. If using those, or others with
>the same problem, listen to the second file labeled (Sony). If using
>Sennheiser HD-280, AKG K240, Fostex T50RP (needs treble boost if possible),
>or most others, try the first one labeled (Senn).
>
>Filesize 809,553 bytes:
>
>http://home.att.net/~elhardt4/Nord_Baroque_Strings_Senn.mp3
>
>http://home.att.net/~elhardt4/Nord_Baroque_Strings_Sony.mp3
>
>---------
>
>Just a couple of demos using my older methods for those who don't know what
>I was talking about. This string orch uses delay lines and a phaser.
>
>Filesize 439,382 bytes:
>
>http://home.att.net/~elhardt3/String_Orchestra_Nord_160.mp3
>
>
>
>All the sounds in this one are from analog or virtual analog synths. Violin
>and cello use delay lines, the Andromeda guitar sounds use a phaser for nice
>body resonance. BTW, filter banks are good for other things too. Just in my
>fooling around I've gotten complex timbres that sound like pianos, harps,
>sitars, bagpipes, and big organ pipes, that don't sound like anything you'd
>normally get from an analog synth.
>
>Filesize 881,478 bytes:
>
>http://home.att.net/~elhardt3/Acoustics_192.mp3
>
>
>
>-Elhardt