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Discussion Starter #1
I have a new Taiwanese tenor that is difficult to play reliably in the low notes, C, B, Bb. It was recently setup by a local tech. The problem existed before and after the work was done. A friend brought a leak light here the other day, and we used it in a completely dark room. We found a tiny leak in the side Bb key. Barely perceptible and easy to miss if you are testing in a room with any ambient light at all. Before I return to the tech I'd like to ask the experts:

Could this leak be the likely cause of the low note problem?
 

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Yes. The higher up on the stack the greater the possible ill effects. You can get by with a pretty miserable seal on the bell Bb. Not at all true on the side Bb on the upper third of the horn. Many leaks manifest themselves on specific notes. The notion that I played down to D and all was well so it must be the pads/cups subsequent to that is simply in error.
 

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Al Stevens said:
I'll try that. What is the homebrew procedure for resealing (resetting? reseating?) a pad?
I've watched every repair done to my horns except the complete overhauls for some time now and I wouldn't think of putting a torch near horns as nice as yours, Al. I wouldn't attempt to bend the keys, either.
 

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Another test is to cut a square from a plastic zip lock bag and put the plastic patch under the pad and hold it tight. Sometimes a small nick in the tonehole or a pad with particularly larger grains in the leather will cause a minute leak that still exists when you simply put more pressure on the pad.

My experience with small leaks in area of the side Bb, C, or G# key is that the low B,Bb, and C come out but it feels like the reed has suddenly gone "stuffy" or "tubby" as I like to call it. The closer a leak is to 1/2 the wavelength of the note's frequency the greater effect it will have on that pitch since it behaves as if an octave vent has been partially opened.


John
 

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saintsday said:
I've watched every repair done to my horns except the complete overhauls for some time now and I wouldn't think of putting a torch near horns as nice as yours, Al. I wouldn't attempt to bend the keys, either.
I just use the torch lighters I use for my cigars. Heat it up and reposition the pad. Not rocket science.
 

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Al Stevens said:
I have a new Taiwanese tenor that is difficult to play reliably in the low notes, C, B, Bb. It was recently setup by a local tech. The problem existed before and after the work was done. A friend brought a leak light here the other day, and we used it in a completely dark room. We found a tiny leak in the side Bb key. Barely perceptible and easy to miss if you are testing in a room with any ambient light at all. Before I return to the tech I'd like to ask the experts:

Could this leak be the likely cause of the low note problem?
Did you check the neck diameter for a leak? Tighten the tenon all the way and then hold it by the cork end and try and rock it up and down. If there is any play there then take it to the tech so he can put a rubberr plug in and do a suction test. If it can't hold suction than that leak is most likely the cause of the bottom end problems. I just learned about this when the tech showed me it on my 3 month old alto, and it was a complete surprise. I had assumed that if you can't turn the neck when the tenon is tight that it wouldn't leak. Not so, it appears. Simple fix is that he will expand the diameter of the neck. He said that the main effect of that leak is to cause problems with C1 and below, and also could be the cause of the occasional motorboating I was getting in low B and Bb. I guess I can toss the wine cork now.
 

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quote: Could this leak be the likely cause of the low note problem?


posssibly.


your problem could be caused by any number of things - mouthpiece, embouchure, a weak spring that holds a pad closed enough for a leak light not to show any light thru but weak enough to be forced open by air when the instrument is blown.

do as Grumps suggests and get someone else to hold that pad down whilst you play.


while your friend is holding your side Bb key get him to do the same on all the keys ( making sure he holds the Bb closed as well seeing as it has a leak)

you may also want to ensure that the pads seal evenly using a feeler rather than relying on a light - which wont show this.

But seeing as this has already been to the tech and its not been sorted correctly then take it back, be polite and get him/her to correct the problem.

As a tech, if something I did wasn't to the satisfaction of the customer, I would expect them to bring it back to get sorted. I always ask the customer to have a test blow in our practice room before they pay, and always tell them to bring the instrument back if they aren't 100% happy.
 

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A couple of other points: Poor pads can sometimes have surface imperfections and tiny leaks that are not evident with a leak light. And leaks tend to be additive. Several small leaks have the same effect as one larger (and evident) leak. Another source of leaks are the bow joints. Also check the seating of the small pads on the octave keys.

If all else fails you can try the dreaded smoke test: get a mouthful of cigar smoke and blow it in the sax with the bell plugged, then see where it escapes...and be ready to clean all the pads afterwards. It is really a last-ditch diagnostic procedure...

Toby
 

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Discussion Starter #12
The tech has it now. When I took it back he dropped a leak light in and got a sheepish look on his face. He found several leaks he had overlooked before. I think he got in a hurry the last time.

Not chops this time. I have three other tenors that do not have this problem.

Thanks to all for the advice. I did the thing Grumps suggested. You should have seen the look I got when I asked my wife, "Honey, can you get a good grip on my B-flat key while I blow in this thing?"
 

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Well, I don't know what's worse Al; a tech overlooking leaks or a horn that quickly falls out of adjustment. Then again, it could bring you closer to the Mrs. I mean... to have her stand by to hold down certain keys. Mine leaves the house when I get the horn out...
 

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It is a very common term of endearment in the West. :)

"“Honey” is the colloquial title of endearment. It is so because honey is sweet, and sweetness is a primal feeling of goodness among human animals. Primal because it came from food, and food is the one most important thing in a animal's life. Among feelings associated with food, sweetness is the most good because when a food item tastes sweet it means its composition has high sugar, the most vital form of carbohydrates, which is the primary chemical element of energy source. Among sweet food items, honey is the most universal. Sugar, saccharin, aspartame are modern, synthetic inventions only known in recent era. Beets, sugar cane fruit, molasses, ... are other sweet things, but none comes close to the universality or naturalness of honey."

From http://xahlee.org/Periodic_dosage_dir/sanga_pemci/take_a_chance_on_me.html
 

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kymarto said:
A couple of other points: Poor pads can sometimes have surface imperfections and tiny leaks that are not evident with a leak light.
I'm not sure this is the case when a bright leak light is used in a pitch dark room with light key pressure. Surely light would leak wherever air could leak as well.
kymarto said:
Several small leaks have the same effect as one larger (and evident) leak.
I'm not sure this has been discussed before. Do you have any references that the effects of small leaks are cumulative? My repair experience is leading me to believe that where leaks are concerned the answer is "Location, Location, Location".

kymarto said:
If all else fails you can try the dreaded smoke test: get a mouthful of cigar smoke and blow it in the sax with the bell plugged, then see where it escapes...and be ready to clean all the pads afterwards. It is really a last-ditch diagnostic procedure...
Yuk. An old school repairman in our area (now deceased) used to do that on flutes, clarinets, and saxophones. He singlehandedly was responsible for more students dropping out of band than any other cause.

I have often wondered if one of those Halloween type "smoke generators" that produces an odorless but visible plume could be substituted for the cigar to do this test.

John
 

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Discussion Starter #19
jbtsax said:
I have often wondered if one of those Halloween type "smoke generators" that produces an odorless but visible plume could be substituted for the cigar to do this test.
I have a couple of cans of that stuff. I've used it in special effects animatronics applications. It comes in aerosol cans with enough simulated smoke in a ten-dollar can to fill a room.

You have to be very careful with it because it is highly inflammable. Don't do it in conjunction with the cigar test. Ka-boom.

You'd have to seal around where you shoot it in—probably the neck—and plug up the bell tightly. That stuff seeks the path of least resistance and will go straight for the biggest open hole to escape.
 
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