To avoid blowing hard you may partially plug the exit hole of Sylpho. It works very well making the sound much louder, but your saliva stays inside and looking through the mouthpiece I see mold growing inside. This was really bad for me, and I have to clean it with antiseptic tissue, which is not quite easy. I guess for some people this may be a problem, and you should clean it frequently. Unless the interior of the instrument is silvered, as it is done in some refrigerators, there is no easy way to avoid it.

The user guide simple says: plug in your headphones and you should hear sounds. Except if you have older version of Sylpho without internal sounds. The guide does not mention that older version at all, and it is not clear whether new updates can be applied, as they seem to differ only by adding new internal sounds. In the older version there is no Sound section in the setup.
Please let us know which firmware still works with Sylpho before link was introduced.

Sylpho selects single output MIDI channels.
Is there an easy way to send output to several channels to activate multiple voices in the connected synthesizer without using sophisticated software?

I do not have link receiver, just the old receiver. I am afraid that many people may confuse the reciever with link receiver and there is no way to update it.
After updating Sylphyo to 1.4 left pinki key stopped working. I have tried different fingering, switching on/off and restarting everything, updated for thesecond time, in some fingering right pink works but left does not.
I went back to 1.3.3 and it works fine. So firmaware 1.4 has a problem.
Wlodek

@Comrade I have recommended Ketron soundbox elsewhere on this list, and tin whistle and many other flutes are there, here is the EWI USB version. Sylphyo will be similar.
https://youtu.be/DnsQQbMFS7o
Wlodek

It would be great to have such ancient flutes in stand-alone version, beautiful sounds:
https://www.suonopuro.net/virtual_ancient_flutes_en.html?i6s153

Unfortunatelly I will not get full Kontakt software to install them.

@friedus Check my page, no video but many examples of Ketron SD2 and SD1000 with Sylphyo and EWI Akai.
http://www.is.umk.pl/~duch/prywatne/Fjukawka/index.htm

A step towards faster program change would be to assign individual parameters to each MIDI channel, for example base key and voice selection. I find myself changing from C3 to C4 quite often when changing voices on my synth. This takes much more time than just changing MIDI channel.

Any information on voices on the receiver?

I have found an intersting PhD thesis on EWI Akai; this may be helpful also for Sylphyo players as it contains some details on MIDI, notation and blowing techniques.

Matthew J. Vashlishan, University of Miami,
The Akai Electric Wind Instrument (EWI4000s): A Technical and Expressive Method.
https://scholarlyrepository.miami.edu/cgi/viewcontent.cgi?article=1577&context=oa_dissertations