Someone Please Give Me A Clue On Tuning

[earl]

1. My reed(s) are a bit sharp in the concertina, when I have the concertina reed pan out for tuning, the reeds are in tune.

 

2. I built a knee operated bellows to test the reeds in the reed pan (but the reedpan out of the concertina)

still a difference in the pitch compared to the bellows in the reed pan.

 

Just why is this happening and how do I compensate for the difference in pitch when the reedpan is out of the concertina?

 

If I measure the #cents off pitch with the reeds installed, can I use that figure to alter the pitch when the concertina reedpan is out of the instrument?

 

Am I making sense? This has be seriously bugged and I would very much appreciate a little help on this subject.

[Dana Johnson]

1. My reed(s) are a bit sharp in the concertina, when I have the concertina reed pan out for tuning, the reeds are in tune.

 

2. I built a knee operated bellows to test the reeds in the reed pan (but the reedpan out of the concertina)

still a difference in the pitch compared to the bellows in the reed pan.

 

Just why is this happening and how do I compensate for the difference in pitch when the reedpan is out of the concertina?

 

If I measure the #cents off pitch with the reeds installed, can I use that figure to alter the pitch when the concertina reedpan is out of the instrument?

 

Am I making sense? This has be seriously bugged and I would very much appreciate a little help on this subject.

You make plenty of sense. Sometimes a concertina reed will sound the same pitch in the concertina rather than out, but it is vastly more common for it to be out a few cents in either direction. The reasons for this can be many, but if you have the reeds still in the reed pan, It narrows the field a bit. One likely reason is the relative support of the pan installed versus out of the box. If the reed pan can move / vibrate at all, the reed's effective vibration time increases and the reed goes slightly flat. when supported by the blocks and tight up against the action board, the pan doesn't move and the reed sees it's actual vibrating length and plays sharper. There are other factors that can affect it, but there is no way to really know in your individual circumstance without a lot of testing.

 

In any case, knowing why won't help much. Your thought about how to deal with it is correct. Most of us generally make a tuning chart, measuring the deviation for each note, then using that information, with the reed out of the concertina, we measure the reed again, and tune it by the required amount, not to the actual note. Once back in the box, it generally is right on unless the reed is loose in it's slot, or something else has changed.

 

Because of their design, I find it most convenient to tune all my reeds while they are still in the reed pan. ( It is a little quicker in my case, but for the standard dovetailed reeds, they come in and go out so easily that most people take the reeds out to tune them. Accordion reeds are usually tuned in the pan n the press side since whatever fastening method is used is not so easy to work with The Draw side reeds on a concertina of the more common of the Hybrid styles are difficult to tune without removing them and re waxing or screwing them back down. I don't know what you've got, so I wont go into more detail, and the Hybrid makers might be better to talk to about that.

 

For tuning in general there may be other threads on the subject. Make sure you have a very thin slip of shim steel tapered to a dull edge at one end to slide under the reed to support it while tuning, and be exceedingly careful not to remove more metal than you need. On rare occasions where I find a reed that is both sharp and weak, I might add a thin film of low temp silver solder to the tip, overshooting the pitch and scraping off whatever is neded to bring it back. The low temp stuff doesn't effect the reed temper, but any flux must be effectively neutralized with a solution of baking soda, and completely cleaned and dried or it will rust.

 

Sounds like you'll only need the tiniest amount of change, so go very lightly. I use a tiny piece of very fine abrasive stick ( you could make something like it by gluing a piece of 400 grit wet or dry sand paper to a piece of popsicle stick( like polishing a Japanese sword ) rubbing paralell to the reed axis, and just polish off a little where it is needed, but if you use a file ( much more common) go on the diagonal not straight across the reed. Remember, long reeds are less sensitive to metal removal, while short ones are extremely sensitive to it, and it is astoundingly easy to over do it and find yourself in an oscillating struggle between sharp and flat with the reed soon ruined. If you are working with no experience, and it sounds as though you are, get some scrap reeds from a defunct accordion and practice on them. you need to get a feel for how much material gives what effect. For the change you are trying for, you shouldn't do more than raise a just visible amount of dust, and for the high reeds, you shouldn't be able to see what you did.

 

Removing steel near the root of the reed (don't localize it but spread it out a little ) lowers the reed stiffness and pitch, removing material near the tip reduces the vibrating mass where it moves the most and raises pitch. Leave the center 2/3 of the reed alone, since any tuning effect is less to none there depending on how close you are to the neutral point, and that area is used only to control the reed's initial stiffness and bending curve / efficiency. There are a dozen ways or more to ruin a reed, but if you go very carefully and lightly and check pitch constantly you'll likely do ok.

 

Likely others will weigh in here, and you probably should wait for a bit more of that before you start in.

[Bob Tedrow]

Hello Earl,

 

assuming reed set; valves pads etc are in good repair...

 

I "strobe" a given reed, in the concertina. Take the top off, take the reed from the reed pan, tune/file the reed up or down as Dana has described, put the reed back in the concertina and check the pitch.

 

 

I do this over and over again by little bits until the pitch is spot on *in* the concertina.

 

This is very time consuming, but I have found no jigs or magic tricks to replace carefull attention to detail.

 

 

Go slow on those little reeds, partner.... use a good needle file, break the tip off just a little bit and you will have a good scraping edge for the absolute final touch.

[Richard Morse]

Just why is this happening and how do I compensate for the difference in pitch when the reedpan is out of the concertina?

I can't really comment on the pitch of the reeds inside the concertina vs in the reedpan outside as we tune reeds by removing them entirely from the reedpan (which I think is the more common way of tuning concertina reeds). The pitch difference between inside the concertina and with the reed (sans concertina or reedpan) in our testing jig is that the reed is between 4-7 cents sharper in the jig. This will probably vary depending on your jig setup.

If I measure the #cents off pitch with the reeds installed, can I use that figure to alter the pitch when the concertina reedpan is out of the instrument?

Yes, most likely similarly as we do. We have a chart split vertically in two (the left side for the left side of the box, the right...) with each reed's designation indicated down the left side column and a dozen so boxes leading out to the right from each reed/note (for each side of the chart). We start by measuring the pitch with the reed in the concertina and jot down the pitch relative to perfect in the first box - for all the reeds on that side of the concertina. Then we remove the reeds and test the pitch of a reed in our jig and note the difference. For instance tested IN the concertina the middle C reed could be 3 cents sharp, and in our jig it measures 9 cents sharp.... So we remove material near the root of the reed to lower it by 3 cents so that it measures 6 cents sharp. It's a relative thing.

 

Do this for all the reeds on that side of the box and then put the box back together and recheck the pitch. Depending on how good your jig is and your techniques you'll find that while most of them are now perfectly on pitch, some will still be off - though by much less, probably now 2 cents flat or so. Note all the ones off pitch and by how much and open the box and go through another round of measuring and relatively adjusting the pitch.

 

It takes a bit of practice - preferably on reeds you don't care about (a dead accordion has hundreds of them!). Not only will you have to adjust the pitch but you also have to readjust the tip set as well. Watch out for burrs and tip spread for vent clearance. Also - before you do your first round of pitch testing IN the box, open the box and make sure all the valves are in good shape (replace any that aren't - and if there're more than a few, replace them all) and reseat all the reeds (and standardize the shims if necessary). Right... and make sure that the reedpan bellows frame blocks have good contact, that the reedpan chamber walls seal against the bellows frame well, the walls top gaskets have good compression, etc.

 

Tuning is the *last* thing you want to do as all the other stuff will have an effect on the pitch and performance of the reed - sometimes making it respond differently each time you do a round - so fix all those other things first!

 

Oh, yes... about those dozen "test round" boxes. You'll be surprised how many accordions it'll take to be able to tune reeds down to within 4 or 5 rounds. We can tell how good our guys are by comparing their tuning charts to see how few rounds an entire concertina can be tuned in. Two rounds is pretty darn good - particularly when the guy can take off exactly the right amount of material when refiling (s/he has to check the reed pitch only once during the out-of-box tuning phase rather than file and check - to find that you have to alter it by 4 more cents, file and check - two more cents to go, file and check - oops over by one cent, file and check...).

 

-- Rich --

[Dave Prebble]

Hi All,

 

I tune in very much the same way as Rich and would thoroughly recommend using a chart to organise the job.

 

I don't know what sort of tuning 'meter' you use, but I found out the hard way that mine gives incorrect pitch measurements (and tone generation) as the battery gets low. On the occasion this happened to me I noticed it fairly quickly but I still had re-tune several reeds.

Once bitten, twice shy..... I now always fit a brand new high quality battery at the start of a new tuning job and use the battery test button regularly. The cast off batteries fuel various radios etc round the house.

 

Regards

 

Dave

[d.elliott]

I work the same way as every one else, by difference.

 

I have cut up an old reed pan to make a set of separate chambers, which I slip the reed into to test on my rig, this means my readings are not only more consistent, but are closer to their 'in-box' value.

 

I also favour analogue read outs on my meters, rather than digital. A have been thinking of a Peterson virtual strobe, has anyone tried these?

 

regards

 

Dave

[earl]

Thanks for the helpful comments everyone.

 

A particular big thanks to Bob Tedrow who patiently spent some time with me on the telephone and answered several questions.

 

 

Earl