Piano accordion question

[accordian]

So my question is what would happen if I didn’t have any Reed leathers? if piano accordion reeds have one note per key then if both reeds were being used it would be the same note unlike diatonics where it would sound bad.

Would it let out more air than. Required? Causing the bellows to open faster?

 

[TomBR]

Loads of wasted air, bellows moving very fast.
When the air presses the reed down into its slot until it springs back, swings above the reed plate and lets a little puff of air through to restart the cycle, it's working quite hard and the air is going through bit by bit.
If there's no valve ("leather") and the air flows through the other reed plate slot and gets to the reed on the other side, the reed just swings out of the way (a tiny bit) and stays open letting loads of air through.

Harmonicas are very different. Most ten hole "vamper" or "blues" harmonicas don't have valves, but the reeds are tiny, a human being has to waste enough air to be able to breathe, and it's actually the "wrong" reed that's speaking when notes are bent, but all that is irrelevant to accordions!

 

[Geronimo]

Well, it's not just more air use. It also means that the active reed has much worse initial response (when it's not the only air path, there is no pressure buildup until it starts sounding). It also has an acoustic shortcircuit through the next reed slot. The usually unvalved piccolo reeds have acoustic wavelength which is much shorter in relation to reed and reed plate dimensions. The lack of pressure buildup also takes the edge off the tight fitting travel through the reed gap, so your reeds sound about 3 classes cheaper. And the lower resistance of the movement gives the reed too high a pitch.

A missing or defunct valve is quite characteristic in sound and one usually knows what to expect before opening the instrument.

Note that missing/defunct valve problems are heard from the reed at the side of the missing valve. Other reed plates are not affected since they live in a separate reed chamber. A valve stuck in closed position (like when it has no surplus sticking over the reed slot and gets its top jammed) will block its own reed, in contrast.

 

[debra]

Try this (on an accordion with at least 34 notes) on the M register: play a scale, slowly, going up and up and check for any "hiss" in the sound. Typically when you reach and pass the highest C a soft hiss can be heard along with the "normal" sound of the note. That hiss is caused by the air wasted by not having valves. Most accordions have valves up to the high B and the first note not having a valve is then the high C.
To avoid this hiss the best reeds are a very snug fit on the reed plate. There is so little room between the sides of the reed and the hole in the reed plate that you don't hear a hiss from the air that can be wasted. This is one of the ways to tell that you have a high-quality instrument.

 

[accordian]

hmm I may have to try re valving some of my reeds because as you may have read in my other post my accordion opens faster then average and some of the reeds are curled into O's yet no rips or anything obvious

thanks