who else can do them? I think they are fun and gives a unique sound. XD I'm known for doing the most usefull things. I should work more on scales... but increasing range and circular breathing has to help also.

I use mulitphonics as part of my warm up. To be able to control both pitches means I have proper control of my lips and proper control of my throat. The multiphonics help me relax and get a better tone. I find I have longer stamina and play more accurately.

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I also have my more advanced student use them for warm-ups.

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AND circular breathing is very good for making sure your embouchre is correct. And it strengthens it.

What are multiphonics/polyphonics? And what is circular breathing? The only picture I'm getting is running around in a circle while hyperventalating.

Fredrick (and others)

Multi or poly phonics is the technique of playing multiple notes at the same time. The Weber Concertino calls for it. To be simple about it you play one note with your lips and you sing a second note. Certain frequencies will produce more notes. So by singing one and buzzing the other you can actually play a chord.

Circular breathing is the ability to play a note continuously.
Let us say the composer wrote an A whole note tied to another, tied to another for 321 measures. There is no place to take a breath, so you circular breathe. The technique is to allow air into your cheeks and then use your cheeks to push air out while you breathe air in, then return to using your regular breathing; or you can switch between the two continuously. Sort of like using your cheeks like a bag on a bagpipe.

Fun tricks that can benefit you. I hardly ever use multiphonics in performance except rarely in horn solo. But I do use multiphonics to warm up and lossen up. I use circular breathing probably every day I play, almost every rehearsal, concert, or show I find a use for it.

Do you have any tips/advice for somebody attempting polyphonics? So far I've been able to play and sing the same note, but trying to get different notes isn't sounding so good.

Tips -
Depending on your voice. I suggest playing a low note (like F second line in bass clef, or C second space bass clef. Then sing a note above that. It is easier to sing above the note you are playing then it is to sing below it.

Practice singing the same note and try to control the beats. There are some pieces that call for things like, " play and sing F 4 beats per second out of tune" I like to do scales up and down playing in 4ths and 5ths. And it drives the person next to you crazy if you can do scales in Major 2nds.

Technique ::
Get a good note on your lips. Then add the singing. Relax. Something you might notice at first is the playing pitch changes as soon as you start to sing. This is usually because your top lip tightens when you start to sing, so your embouchre changes and results in your playing pitch changing. But just relax and have patience. Once you succeed at this you will notice some singing pitches will change your playing pitch and try as you might you can't stop it - this is more complicated to explain but accept the fact that certain frequencies react with other frequencies and things happen beyond your control.

HAVE FUN

I have yet to see multiphonics in written horn repertoire, I shall have to check out those pieces mentioned earlier.

I think the easiest instrument to do multiphonics on is tuba, sing it is so easy to maintain the buzz while singing, and there is more distance between the played note and sung note. Trombone is another instrument that it is not particularly difficult on, the higher we go, the harder it is to do. So far I have only heard male players use multiphonics, so maybe it would be easier to do it if you are a girl and have a higher voice. I wouldn't know.

Either way, the trick to doing it with ease is to start as low as you can, try playing scales in octaves, then work on fifths. One thing I love to do (easy on tuba, not so much on horn) is sustain a low drone, maybe between lowest C and Ab, and sing Scotland the Brave over top of it. It's a great exercise in intonation, especially when you are done with the singing part and realize that you ended up playing the drone out of tune. So be very careful about intonation.