Acoustic instruments are almost all monophonic or one voice at the time, except for keyboard instruments. Only some free reed instruments have polyphonic capacity, like accordeons and melodicas. However modern knowledge of acoustics and computer aided design can create some sophisticated instruments. Making free reed or other system based polyphonic acoustic instruments is perhaps possible. Then “polyphonic symphony orchestra” can be made. Even string instruments can have polyphonic sound when played with special curved bow. So violins and cellos can be polyphonic too, if their string curvature is changed to less sloped form and curved bow is used. Bazantar or other string instruments with symphatetic strings can be manufactured using polyphonic bow also. For free reed instruments manufacturing polyphonic versions of saxophone, clarinet/basset horn and oboe (heckelphone and lupophon) can be made. Altough these are tuned monophonic (“transposing” etc.) polyphonic versions when played several keys together will create polyphonic sound. Clarinet has max 27 keys in Voll-Oehler system and that has even extented to 30 keys, and basset horn is extented clarinet so it should have even more keys. Oboe and its derivates has 45 or more keys. Saxophone has 23 keys and 3 extra holes that can be covered like extra keys. If the key system of these instruments are changed to typical piano style like melodicas, now full polyphonic sound is possible and keys increased to woodwind instruments to piano like numbers (49, 54, 61, or 88 keys per instrument). Making accordina/ accordeon type button keys increases keys to about 200 keys to max like largest accordions today. These polyphonic instruments will be “blow accordion” or melodica type instruments, but acoustically tuned to sound like saxophone, clarinet/basset horn, oboe etc., and can even look like saxophone, oboe etc. In netpage patmissin.com is “History of western free reed instruments” that mentions Hohner Hohnerette, trumpet like blow accordion/ melodica, Couesnophone (Goofus) etc. old instruments using melodica or accordion type structure. So trumpet- like instruments can be also be build using polyphonic principle. Also “harmonica patents” section of patmissin.com mentions Hans. A. Bruder german patent 1080385 harmonica like 8-voice instrument (1960) that is like flute, so “Bruderphone” type polyphonic flutes can also be build. How polyphonic sound is possible? Free reed instrument with single set of free reeds , double set of reeds (something like vibrandaneon?, italian double(?) set of reeds melodica with high sound quality, invented in Italy originally at 1800- century), or multiple reed (blow accordion) instrument that resembles saxophone, clarinet or oboe can be made, and even something resembling trumpet / Hohnerette. Acoustic tuning can be made using modern know- how of acoustics and materials. Plastic, carbon fibre, different metals like silver, bamboo wood and different wood materials etc. can be used (saxophonoses are made using bamboo wood). If high density metals are needed then lead or tungsten can be used, and even plastic mixed with tungsten like shot shell shots are using. Materials that can acoustically “tuned” like Flaxwood, mixture of wood and plastic, can be used to create these new polyphonic instruments. Symphony orchestra can now have polyphonic sound, and ordinary melodicas of different pitches (bass melodicas, soprano melodicas) accordinas etc. increase sound palette of orchestra. Sound and shape of these instruments resemble monophonic saxophones or flutes but inside these instruments are accordion/ melodica / harmonica type. String instruments (4 or 5 or 6 string cellos / contrabasses, Bazantar, Sympathetic drone cello, Campanula, Harpeggione or Arpeggione) can be played polyphonic using Vega bow, Bach Bogen bow, or Vladimir Pliassov `s curved bow (US patent 5918297, 1999), and changing the curvature of strings to less sloped so less curve is needed in the bow. When Goofus (polyphonic saxophone) come to market it sounded like mouth blown harmonica and not at all like saxophone, these about 100 years old novelty instruments were not a success based on harmonica/ melodica polyphonic principle. But now knowledge of acoustics and acoustic resonance of different materials is at another level, and computer aided design is at use. Altough instruments are free reed / melodica based their sound can be adjusted and sound color and pitch fine tuned with modern materials like synthetic materials (plastic, carbon fibre), metals, and flaxwood wood/plastic hybrid, different wood materials, thermotonewood ( Landola guitars) etc. Altough sound of these melodica / vibrandaneon / blow accordion instruments is not exactly like saxophone, trumpet or oboe, close approximation of sound resembling these instruments is propably possible. Saxophone- like polyphonic instrument with 200 button keys like accordion and polyphonic sound would be suitable for jazz etc. music, 200 key “hohnerette” trumpet is also possible. Or instruments would look like traditional saxophone, they have similar keys and tuning, but polyphonic capacity. Now polyphonic symphony orchestra is possible. I choose oboe and basset horn because they already have lots of keys, so adding polyphony to them would make them usable polyphonic instruments altough they are monophonic “transposing” etc. type in standard form. Their innards would be a set of free reeds accordion based, melodica / accordion type, but shape resembling trumpet or saxophone or oboe and they would be actually “blow accordions”, not saxophones or oboes etc. If ordinary melodica shaped instruments can be tuned to sound like trumpets, oboes or saxophones also normal melodica / accordina shape can be used. Hans Bruder s “bruderphone” would be polyphonic version of flute (altough it is 8-voice harmonica). Heckelphone and Lupophon are versions of oboe with different tuning and propably lots of keys like oboe also so they can be used to players that are not used to play accordions or melodicas. If “normal” instruments like saxophones, clarinets and oboes would have polyphonic capacity but normal “monophonic” tuning (or transposing tuning or whatever is the correct title) musicians can use them like normal clarinets or saxophones but when needed add extra notes for polyphonic sound. If instruments have button (accordina) keys then even maximum 200 key polyphonic sound is possible (humans however have only 10 fingers), but now the tuning of instrument is not exactly like monophonic instrument (because monophonic instrument has less keys). Tubax is crossfeed between tuba and saxophone, so it can be be basis for free reed polyphonic tuba, replacing monophonic tubas in polyphonic symphony orchestra. Or use giant “contrabass melodica” with tuba-like horn/bell to amplify sound. Melodicas and accordinas can be played using two hands simultaneusly, same system is recommended for these new class of polyphonic instruments. Piccolo clarinet -type instrument can also be made as replacement for flute in free reed polyphonic instruments. Hohner Claviola was an attempt to manufacture whole new breed of free reed instruments, and after Claviola other similar instruments were planned to be made, but even Claviola production had abrupt end. Claviola was invented in the 1960s, since then no new polyphonic acoustic instruments have come to market, and 50 years have already passed without new inventions in polyphonic acoustic instruments field. Because almost every possible acoustic instrument is already invented, only way to make something new is to make polyphonic acoustic instruments, monophonic instruments have already been made. But nobody seems to be interested making polyphonic acoustic instruments altough it would tremeondously expand palette of sound of instruments and possibilities to compose music polyphonically to large orchestra and smaller groups and bands of players. Cellotar, Harpeggione, Togoman GuitarViol, Guitariole, Greg Ryan Instruments are all crossfeed between guitar and cello. If electric cello/guitar/violin hybrid is played with hands it is “monophonic”, but played with bow it is polyphonic instrument, if bow is curved or strings are not curved like cello. So electric guitarcello is in fact electric polyphonic guitar played with a bow. And etcetera, different kinds of electric and acoustic polyphonic instruments can be made. If it is possible to make polyphonic instruments using some other than free reed, I don t know, but modern computer assisted design and acoustic knowledge perhaps other ways than free reed (in western music accordion was invented about 150 years ago, since then no new polyphonic acoustic method has not been invented) can be used to make polyphonic sound. Harmonichord / Mellowchord was free reed instrument invented in USA in 1940s (info is from patmissin.com netpage “western free reed instruments”) that was designed to begin a whole new family of instruments like Claviola, but nothing much came from it either. Hans Bruder s harmonica-flute never went even prototype stage. Modern computer design and acoustic knowledge can create instruments perhaps better than these failed attemps, and early 1920s Hohner novelty instruments and Goofus. Vibrandaneon has good sound but it has invented already 100 years ago and modern versions are like melodica in appareance. Chromatic button accordeon can have almost 200 keys (64 treble plus 120 or more in bass side), so for example polyphonic saxophone-sounding instrument with 200 keys would propably be popular, like accordion but using blow accordion principle, and perhaps even looking like saxophone, except accordion buttons. Or simply making accordions and melodicas to sound like saxophone and clarinet and not altering their physical appareance, only thing that changes is sound, that is like clarinet or saxophone or oboe, not like accordion or melodica. From patmissin.com “western free reed instruments” is Symphonium by sir Charles Wheatstone 1828, Apollo Lyre by Ernest Leopold Schmidt 1833 that sounded like clarinet, oboe and bassoon and “horn” at the same time, and Harmonicor / Harmonitrompe by Luis Julien Jaulin 1861 that was like trumpet with “piston” keys (25 key trumpetlike instrument). Since then interest to create polyphonic instruments waned. Melodicas are sometimes mounted like piano and air blown by tube that is in players mouth, so that all 10 fingers can be used. Similar instruments in polyphonic symphony orchestra can also be in use, and if foot pedals are used too, polyphony increases to 10 fingers and 2 feets. So this instrument is like ordinary reed organ / harmonium that has air blown by tube in mouth not pedal pumping. Now keyboard can be 88 key piano style, or similar like Tonal Plexus that has over 1000 keys, or microtonal keyboard type 1000 or more pentagonal or hexagonal or octagonal or other shape keys, or button keys like harmonica, tuning like chromatic accordion or microtonal system or any other suitable tuning and 1000 - 2000 keys. Pedalboard increases tonal capacity even more. If pedalboard is in use that is like ordinary harmonium (reed organ) with mouth tube, and sound is like clarinet or oboe or saxophone, not reedorganlike altough physical appareance is. Large “contrabass reed organ” doubles tuba and has similar sound like tuba, that has pumped by foot pedal and has large horn/bell to amplify sound. If pedal power is used to blow air no mouth tube is needed and result is reed organ / harmonium with sound like saxophone or clarinet or oboe. So “symphony orchestra” has large crowd of reed organs / tube blown melodicas that are grouped like regular symphony orchestra, and their sound is like orchestral oboe or clarinet, but they are melodicas and reed organs played using 10 fingers and mouth tube or harmoniums with or without pedalboard. Small piccolo melodica can double as flute. That is one solution for polyphonic acoustic instruments. Hohner made 1950s/1960s reed organs that were essentially accordion turned to reed organ and played on piano keyboard (combo reed organs). If air is blown by electric motor mouth tube or pedal pumping is not needed, but that sounds like cheating because purpose is to build acoustic polyphonic instruments. But those polyphonic instruments can be any shape and size, like traditional saxophone or clarinet/basset horn or oboe or tuba, or accordionlike (altough their innards differ from regular saxophone or tuba) and not even free reed based if other ways to produce polyphonic sound is found. Flaxwood and Aqvacomp have built clarinet prototype using flaxwood (acoustic material made of acoustically tunable plastic and wood mixture) and violins with thermotonewood “aged” wood material were planned also. String instruments can be polyphonic also, bazantars (cellos) and violins played by special bow and the strings of these instruments are not grouped so curved like ordinary violin or cello so that bow can more easily play several strings at once. Campanula is cello with additional strings and it has alto viol and violin versions also. Making polyphonic versions of them is possible with Pliassov s bow or other. “Sympathetic drone cello”, and Hurdy-Gurdy-Cello (at berneluthier.fr netpage) are both crossfeed between crank driven hurdy gurdy and cello. Making polyphonic versions of them is propably also possible. Polyphonic hurdy gurdy (crank driven violin) propably possible also. Different “bowed guitars”, guitar built to be played with the bow, are polyphonic if bow if used instead of fingers to play them, (Alan Miller bowed guitar, Guitariole by Vincent Magrini, Ha-Shem guitar by Esteban Antonio). “Indian violin” by nouvelleluthierlab.com and other extra strings violins and stringed instrument designs with extra sympathetic strings can be polyphonic also perhaps, if the extra sympathetic strings don t mess the sound when several principal strings are played at once, then not just ordinary violins or cellos could be polyphonic. “Foldable guqin dulcimer” by Mighty Q is hybrid between “mountain dulcimer” and guqin (chinese instrument), both can be played with bow if needed. Not only conventional violins and cellos but any string instrument with strings and played with a bow can be transferred to polyphonic if it is played with polyphonic bow, and there is enormous range of different string instruments that are played with a bow around the world, so polyphonic string instruments have several designs to choose from. These instruments can be acoustic, electro-acoustic (with B-Band electret film pickups, piezolectric pickups) or electric.