Tweaking harmonicas: Measure what you change

This is about methodology.
Here's a video demonstrating some of the things that are straightforward to quantify so that you can make changes that have a measurable benefit.
Some of these things include:
Tuning: It's easy to measure the pitch of a reed and whether it's in tune with another reed. Play all the octaves available and listen for "beating".
Bending: Bend the 3 draw (or any other bend) with as little force as you possibly can. You will find a "blind spot" somewhere in the middle where the workload is handed off from the draw reed to the blow reed as you bend down. How much work is needed to "skip over" this blind spot can be felt, albeit subjectively; it tends to be more work on lower key harps. We learn to "skip over" this blind spot early on when we are learning to bend. A well-playing harp can be played with very little breath force without having to work hard around the "blind spot".
Reed shape efficiency: By playing a single reed using your lips on the plate off the comb, you can get sensory feedback on how easily the note responds, how much flow you need to make the note sound strong, and how loud the note is. A well-shaped reed will make the whole reed plate vibrate when you play it.
Reed shape efficiency (again): By bending the single reed's note down, you can determine if the reed is prone to squealing. That's a great indicator of how efficiently the reed is set up.

[@majikmuzik8036]

Thank you for adding this! Would be great to see how you’re manipulating the reed. You alluded to the mechanics and the physical manipulation of your embouchure and/or the physics behind the read and what is happening during the bend From a vibration standpoint that makes the pitch go flat or sharp. Sort of like when a guitar string is plucked firmly the pitch goes sharp? What is the actual mechanism that causes the pitch to change? Great primer for expansion thank you sir!

[@davidmathews2124]

Great info. Wish your hands/fingers did not block view of how you were doing the adjustments...and that the focus was right on instead of fuzzed a bit. Would have helped understand more clearly...at least for me.

[@212sean]

Great video but your hands are covering what you're actually doing to the reed when you adjust it. It looks like you're pressing and rubbing the reed in some way. Are you pressing down at the base of the reed to decrease that gap, massaging the center to create a curve, or doing something else? Thanks.

[@chrisl4676]

Thanks for sharing this theory and technique, Andrew. There is far more information in this video than the verbal content alone! Anyone with Tuning and Gapping 101 under their belt will find this takes them to a new level! I intend to not just watch, but study and apply! Cheers!

[@jamesmares4206]

did you take.some curvature out of the reed to make it pass through the slot evenly

[@Rickblues46]

You said using something like white paper to assist in seeing reed gaps ... do you use a light box at any time ? Great info and presentation btw

[@aniloberoi]

Thanks sir. Regards.