Sal-Mar Construction

 

Hardware Design of Real-Time Musical System

by Sergio Franco 

(excerpts) 

1. Importance of Real-Time in Electronic Music

With the advent of electronic music, the roles of the composer and the performer have been placed in a new perspective. Traditionally, musicians have tended to specialize in either one role or the other, or have tended to play only one of the roles at a time. This has happened mainly because of the considerable difficulty encountered when composing and performing are carried on simultaneously.

When a musician improvises at an instrument, he is essentially composing music in real-time. This means he is thinking and evaluating very quickly a series of possibilities out of which he makes appropriate choices, which in turn lead to the execution of the various mechanical motions necessary to produce the music he wants.

Because of the difficulties encountered in doing all these things at once, musicians have tended to specialize either in the inception/evaluation process (composition) or in the execution process (performance), and have developed the notation of musical scores to communicate among themselves. Thus, the composer need not be principally concerned with the quick thinking and decision making of the improvisational process, but can pursue his inspection of musical possibilities on his own time scale.

What is even more important, to appreciate the effects of his choices and changes, he does not need to try them out on actual instruments because he can rely on his aural imagery, a faculty he has developed through experience either by playing instruments or by listening to others playing them, or both.

In developing his aural imagery, the musician is certainly helped a lot by the fact that he deals with a limited set of instruments whose characteristics extend over known and predictable ranges.

In electronic music the situation is quite different. Because of the new kinds of sounds that electronic instruments are capable of synthesizing, it is very difficult for the musician to develop the kind of musical imagery that may suffice to assist him in composing on his own time scale and away from his instruments. If the composer is to come up with something musically meaningful at all, it is absolutely essential that he actually hear the effects of his choices, his trials, and his alterations as he makes them, so that he can directly evaluate them in the context of the whole composition. In other words, the concept of direct feedback has come to play a dominant role in the electronic music composing process.

Another important change brought about by electronic music involves the relationship between performer and instrument, and is due to the much greater detail in which the performer is required to control the various musical parameters. While in conventional instruments such parameters as timbres, attacks, decays, etc. are, to a large extent, fixed, built-in features, in electronic music they are left to the discretion of the performer, who must therefore specify and control them directly. If this feature allows on the one hand much more freedom of choice and experimentation, on the other it imposes a more demanding control burden upon the performer, and it certainly renders the communication among musicians more complex than with conventional instruments, where the notation of the musical score is usually adequate.

As a result of the above discussion, it should be clear that in electronic music the distinction between composer and performer ceases to exist, partly because the composer needs to try out his musical ideas on the instrument by himself, and partly because of difficulties of communication among different people.

Furthermore, having accepted the notion of direct feedback as an indispensable ingredient of the improvisational process, it is of paramount importance that the composer/performer be allowed to interact with his instrument on the time scale of the music he is improvising, that is, in real-time.

As shown in the block diagram of Figure 28, the realization of the sound distribution system requires a total of 96 audio gates. With a number of this magnitude, the cost per gate plays an important role in the choice of the circuit realization to be adopted.

An audio gate, besides satisfying such obvious requirements as low distortion, high on-to-off transfer ratio, and low control signal feedthrough, must also exhibit specific transient characteristics in order to ensure proper audio switching.

The last requirement is motivated by the fact that when a sound is switched on or off, spurious partials are generated which may alter the tonal character of the sound considerably, as has been discussed in connection with sound enveloping.

As Fourier analysis reveals, the amount of spurious partials accompanying sound switching usually increases with the rate at which sound builds up or decays. Thus, unwanted switching effects can be easily reduced by employing gates with low switching speeds.

From the viewpoint of sound movement control, however, it is desirable to have fast gates so that sounds can be switched around the performance space at arbitrary rates. A compromise between the two conflicting requirements can be determined experimentally.

Analog gates based on solid-state, electro-optical devices like Raysistors or Vactrols usually exhibit predetermined and highly asymmetrical switching characteristics which render these components unsuited to the present application. The cost of these devices at the time of design was also a key factor that contributed to their rejection.

The smoother for the harnonic tone generator has been real-ized with two CA3080 OTArs in the manner i]lustrated in Figure 1p.This circuit realizes a tvo-pole,maximally-f1at, low-pass prograrnrnable fil-ter. Due to the absenceof the voltage-to-current converter and diode compressor, signal conditioning at the OTArs inputs i-s achieved by means of resistor attenuators, as shown. Tire resj-stcr values have been chosen so that the bal-anced outputs from the progranraable mixer can be tied to

 the inputs of the first 0TA directly, without the need for additional ancilfary circuitry. AIso, because of the finite imped.ance presented. by the attenuators, the output from each OTA naust be buffered. by a high input-imped.ance decoupler. This task is performed. by the pair of FET-transistor

source fol-lowers. The voltage-offsets associated vi-th the fol-lowers $o not affect the dc level of the filter because each follover is placed insid.e the feed.back loop of the correspond.ing OTA.

Digital Waveshape Generation

Because of the discretization introduced by the sampling technique, the control of tonal qualities can be exercised only over a limited bandwidth. According to the well-known sampling theorem, the order of the highest harmonic that can still be represented with the sampling process equals half the number of samples contained within one waveshape period.

Thus, if the harmonic generator is to span a wide tonal scope, the number of sampling intervals should be as large as possible. A high sampling density, however, requires a commensurably high frequency for the sequential scan of memory as well as a large memory size to accommodate the samples.

As it has already been pointed out in connection with the relaxation oscillator, the accurate generation of an exponential frequency over a range of three decades becomes more and more difficult as the range is shifted in the direction of higher frequencies.

A compromise has been achieved with the choice of a time resolution of 32 samples per period and an amplitude resolution of 15 levels per sample. Since the tonal bandwidth is determined solely by the number of samples, the amplitude resolution need not be as high as the time resolution.

It should be noted, however, that the presence of the mixer results in an effective increase of the amplitude resolution because it allows for the programming of arbitrary ratios between corresponding samples of the incoming waveshapes.

(Sergio Franco was one of the people that designed the Sal-Mar Construction)

This excerpt is shared for educational and research purposes only, to facilitate discussion and understanding of electronic music history. If you are the copyright holder and object to its publication here, please contact me directly, and I will remove it immediately.

Arabesque Synapse Magazine

 

***

 

This is recorded using VLC Media Player set to shuffle the playlists ,there are 3 short playlists here made from a Sample Bank i made from earlier recordings

Holiday Filter

 This maybe should be called the Holiday Filter and the Forever Frequency Shifter . Sometimes DIY projects get prolonged and stretched so much .

 First i built the Yamaha GX VCF clone from MOTM some 10 years ago or more with a pcb i designed and using just BCMXXX matched transistors instead of the CA3046 , and it worked ..but there was this noise that i could not get rid off . I liked the filter very much and the gritty resonance but i could not fix it. Years later i discovered the Old Crow's BPF version ,and i made a layout for that one and built it and it sounded wonderful ,so much ..that i wanted to make the MOTM version again . 

So i made a new layout and fixed the new layout a few times and after a long wait for it's turn i ordered the PCB's from China right before their New Years Eve ,so i waited 10 days for them to send the package .... and here it's been two months now and the PCB's arrived exactly on night before Easter ,so it's right to call this filter a Holiday Filter . 

I am not sure where these VCF's will go as i did not intend to build another synth , i am more interested in recording more feedback music or drum machine loops so i made a panel that serves just as a processor ,it should contain a VC Delay with 2 x Bazier Curve Generators , Envelope Follower and VCA , a Frequency Shifter and 2 x Yamaha GX VCF's . 

Now the F.S. is something that has been dragging around the workshop for years , i got the PCB's for Dome Filter and Ring Mods but still missing the VCO PCB , so i redraw the YuSynth/Ian Fritz Quadrature LFO/VCO and i intend to order the PCB's soon . This is not one of those projects i get obsessed with and it's a shame cause i know there is lot of new sounds to discover with adding these just few modules to my set up. 

The Yamaha GX is a vintage organ/synth ,massive and very expensive instrument that was used (very little) by Led Zeppelin. The Envelope follower that is featured on this panel is the music easel follower ,while the VCA is from Electronotes ,those two modules i have already built along with the VC Delay from Scott Bernardi . 

Maybe it's one of those things i never complete sadly ,新年快乐 & Христос Воскресе!

Few Reason Loops .

in 120 BPM .

One more panel design ...

 

This elaborate single panel synthesizer contains the following modules :

Buchla 258 (Single VCO)

Ian Fritz 6 Phase VCO 

Ian Fritz /R.C. Bass Waveshaper (Electronotes)

Serge Triple Waveshaper 

Paparail VC Aux / Panner /VCA

Yu Synth Dual RIng MOD

Wiard Wogglebug 

Serge DUSG + USG

Serge Smooth / Hagiwo Bazier Curve x 2

Serge Extended Resonance VCF

Serge '73 VCF (Both with summed outputs)

Osamu Hoshuyama Dome Filter

Buchla 106 (Half) + Electronotes VCA

Serge Noise

                                                                  

feedback music

 

This is recorded with diy mixer and pedal.

Mixer

 I rehoused the Mixer i built for myself as the first build had no printed panels ,the cheap switches i used for muting the channels started failing ,and there were too many wires using converters for each banana - jack i use , so i made it all standard 4mm banana sockets except a few ,i had to minimize so in that sense here i am missing two limiter/saturators and one optical compressor and a joystick panner and they will need to be in a separate box , instead i included here a small 4 channel filter bank based on schematic i found at electr-music . This is just basic mixer and actually a Buchla 106 ,with additional 4 mixers from Serge Schematics used as aux channels , there is also 3 SIAM Equalizers .

***

 Zahar Pavlovič se zamislio i hteo da ode u bosjake, ali je ostao. Tuga

i nemaština su ga tako dirnule — zbog neke nepoznate griže savesti što

se otkrila u njegovom srcu poželeo je da neumorno hoda zemljom, da

susreće tugu u svim selima i da plače na tuđim grobovima. Ali sprečili

su ga predstojeći poslovi: starosta mu je dao da opravi zidni časovnik, a

sveštenik da naštimuje klavir. Zahar Pavlovič nikad u životu nije slušao

muziku — jednom je u sreskom mestu video gramofon, ali su ga seljaci

dokusurili i nije svirao: gramofon je stajao u krčmi, zidovi kutije bili su

odvaljeni kako bi se mogla videti prevara i onaj ko peva, a u membranu

je bila udenuta igla za krpljenje. Proveo je mesec dana u štimovanju

klavira, isprobavajući setne zvuke i razgledajući mehanizam koji je

stvarao takvu nežnost. Zahar Pavlovič je udarao u dirku — tužna pesma

se rađala i nestajala; Zahar Pavlovič je gledao gore i čekao da se zvuk

vrati — bio je odveć lep da bi se nepovratno izgubio. Svešteniku je

dosadilo da čeka sa štimovanjem, pa je rekao: »Ti, čiko, nemoj badava

da puštaš tonove, nego se trudi da stvar završiš do roka, i nemoj

dokučivati smisao onoga što ti nije potrebno.« Zahar Pavlovič se uvredio

iz dubine svoga majstorstva i napravio u mehanizmu tajni deo koji se

mogao za sekund ukloniti ali se bez specijalnog poznavanja stvari nije

mogao otkriti. Posle je pop svake nedelje pozivao Zahara Pavloviča:

»Dođi, prijatelju, dođi, opet se izgubila tajna snaga muzike.« Zahar

Pavlovič nije napravio tajni deo zbog popa, niti zbog toga da sam često

odlazi do njega i uživa u muzici: ganulo ga je nešto sasvim suprotno —

kako je napravljena sprava koja uzbuđuje sva srca, koja čoveka čini

dobrim; radi toga je i ubacio svoj tajni deo, koji je bio u stanju da se

meša u milozvučnost i da je maskira grubim tonovima. Kada je, posle

deset opravki, Zahar Pavlovič shvatio tajnu mešanja zvukova i

mehanizam treperave glavne ploče, izvadio je iz klavira tajni deo i

zauvek prestao da se zanima za zvuke...

АНДРЕИ ПЛАТОНОВ

ЧЕВЕНГУР

20 Years Electronic Music

 

These miniatures were composed 20 years ago , and released for Shkart Netlabel in 2006.

Canvas

 

These are made 14 years ago using nothing but Sound Forge and simple one shot samples , i wanted to make some music with tempo but without the use of a classic DAW and a Sequencer. There are 4 miniatures in this release.

Uncorrelated Rhythms

 

This is recorded over the last two months , there are more then 100 recordings i did with my DIY Groove Box ,and sometimes using a VCF and a Ring Mod from my DIY Modular . The only commercial piece of gear is a Mini Universe Reverb Pedal . This is more of a Automatic Hip Hop . Automation is made using Wiard's Neural Pulser's Clone and Buchla 208 URV . In this Bandcamp release there are 18 short loops/pieces ,free to download . 

a little mess..

 

SInthai Solo

 

This little monophonic FM synth is based on Hagiwo's FM Oscillator ,it's just Arduino with the help of AI and therefore not Duophonic at least , but i decided to keep it , it's got 7 waveforms ,envelope ,pitch bend with 2 semitones ,range and depth controls , there are dedicated cv inputs for all these functions , now there was room on the panel to add a simple envelope generator as there is pulse out on keypress at D1 , but guess i'll just do that part separate ,the Joystick is just voltage source to modulate inputs . It's all done on stripboard .The keyboard is cut out from larger Casio CT660.

Перекрёсток - 1989 - Я культурист

 

***

 

Arduino Drum Machine

 as i found it here : https://github.com/gavD/arduino-drum-machine/tree/main  ,modified with help from Grok