@Arindam please don't practice with a tuner, it almost always ends badly. Tuners are visual and cause you to train connecting your muscles to your eyes. When you make music you don't use your eyes you use your ears. The only way you can use your eyes to see if you are in tune when you are actually playing is by looking at the audience and see if they cringe because of how out of tune you are. It is much much better to train your intonation against a tonal reference. Use a online virtual keyboard to play the note you want to produce and learn to match what you are playing to what you hear. This will be much more useful when playing music.
http://www.bgfl.org/custom/resources_ftp/client_ftp/ks2/music/piano/

This may be of general interest, an online tuner:

http://www.seventhstring.com/tuner/tuner.html

I am not sure that I understand the question. Sounds in the choke? Do you mean high pitched squeels; see waxing the rivet end. Do you mean the choke doesn't hold; see gapping and arcing.

what is the main reason for sounds in the choke

If you look on a spread sheet to the left near the cleft you will see flats and sharps. With reading music the lines only represent the letter it is but not whether it is flat sharp or natural. Just in diatonic scales there are 7 notes. Hymnals are good to use if brought up catholic for instance silent night.There is a flat on the E and a flat one the B. Or in other words a flat on the top space and the third line up from the bottom. So there are 7 notes that can be represented by the music.(Actueally more if you right a natural mark near a note. But in silent night they do not because all the notes come from the Bb major scale.) Bb C D Eb F G A Bb Are what each line represents in silent night. I suggest you grab a song. Look at the lines starting at the G cleft.(to do this you need to know with G cleft the G is on the second line up. Then you can find all notes from there). Right out all your notes till you return to G again. Then find the step pattern between the notes. Like in Silent night it is whole whole half whole whole whole half. This is the pattern to a major scale. The pattern to a minor is flat the 3rd (3rd note of the scale 6th and 7th). In blues when they say a 1 4 5 they are referring to the major scale notes of the key the song is. Two things I have learned that were more than obvious but missable and very helpful were 1 4 5 is from the major scale 1 2 3 4 5 6 7. And that in sheet music it is a scale being represented with uniform half step whole steps patterns. The 7 lines only represent 7 notes at a time.(You can use markers to show different sharps and naturals of a note. But mainly in hyms and other stuff they stick to those notes in the scale) because those are what sound good.

I don't think these songs can help you to learn minor progressions. What I was talking about was learning to pitch single notes. Anyway I'd suggest you learn to read and learn music theory despite having a good ear. It will speed up your learnig curve and make communication with other muscicians a lot easier.

You said that: "I find that playing tunes I have known from when I was very young are good for practicing my intonation. When I play songs I learned to sing as a child I am very aware of the notes I want to play and how they should sound. Don't think of the notes as "hole 5 overblow" but instead hear the note you want to play in your mind before you play it." ..... This is wonderful advise - especially for someone like me who doesn't read music, and who doesn't play a piano or any other instrument except a harmonica - but who can mimic most things on a harp once I hear the pattern. Unfortunately, for example, I don't know one minor progression from another. So, I don't even know which songs to pick to do what you suggest. Do you know any internationally shared children's songs that would work to learn basic progressions? If you could post a few, or tell me where I could find some, that would really help. And, I often find that words along with notes help me too.

Thanks

I have students that play Lee Oskars and they can overblow pretty well. The seydells are very good indeed and so are the hering harmonicas that are specifically made for overblowing. However I think that all harmonicas need some personalising to play well.
Anyway, take a look at this page for some opinions on overblow harps:

http://www.overblow.com/?menuid=190

Regarding harmonicas. I have tried almost all Hohner diatonic models now, and the model that suits me best is the Special 20. For "traditional" blues with bends, that is. I can manage to play overblows on Special 20s, from low G onwards, but not necessarily from the 4 blow hole onwards. I recently read that the Seydel 1847 Silver is better suited for overblow playing. And that Lee Oskars are not suited for overblow playing at all . Can you share your experiences with out of the box harmonicas ? And do all brands/models need to be adapted ?

Thanks Tinus Probably I need to learn a lot. Thanks so much for your advise :-). SukaJazz in Jakarta

btw, there are almost no harmonicas that are designed to play overblows.

If you just started to play one month ago you do not need another harmonica to play overblows; you need patience and lots of it. You might want to develop some other skills on the harmonica before deciding that it is the harmonicas problem that you fail to get any of the overblows.

Please help me; I just begin learn harmonika 1 month ago I just bought Major Diatonic Lee Oskar by Tombo, I want to play jazz songs but difficult to overblow F# in hole 5. Is it posible to overblow F# in hole 5 for Lee Oskar? I am getting doubt if this harp is designed not to be overblow. please help me.

i'm a rookie in playing the harp, but this site has helped me so much, so far. bravo!

I agree with Ludo, for overblowing pucker or lipblock is much easier. But I only play with a lipblock/pucker so my opinion is colloured by my experience. I alsmost never TB so playing overblows with TB is difficult for me. However I can do it and do it regularly to practice my technique. I couldn't play a scale with a TB OB I think, but then I have never tried.
If you want to play TB overblows, go for it. they can be played and with some work you can probably play them as fast as any note. Don't let the idea that something isn't possible stop you from trying it anyway.

Hi Boris, I don't know to what extend Tinus uses TB, but I think for OB-ing pucker absolutely rules!
I seriously have my doubts about people's claims of OB + TB proficiently.
As far as I've heard Dennis Gruenling for instance, he doesn't OB that much, so I suspect it's a matter of mixed embouchure rather than pure TB.
I use mixed embouchure constantly - rapidly switching between TB and pucker.
My 2 cents...

Huh, I played TB primarely, now I'm practice pucker, as I start using overblow
and pucker is still a bit unnatural for me. So I can OB 5-6 holes with TB very easy bend it and use it. But lower or higher stil not )):

Results so far...
I've been practising it a bit on my whole tone harp, so every key I mention can be compared to an overblow on hole 1.
(The blow notes of the whole tone start with a low E, then Ab, C, E, Ab etc., and all have a draw note a whole step up).

Strangely enough I have no problems doing them tongue blocked with the LEFT side of the mouth on C, E, Ab and C again.
The right side is more problematic, and will work only on C and E.
"Regular" overblows work on all 10 holes ofcourse.

"a little practise" is what'll try for a while, and then get back here.
I invited Dennis Gruenling to this discussion (he's gone for a few days though) also, since he's the only one I know of that plays TB-OB's; could get very interesting.

Yes I tongue block overblows to practice my technique. I find that if I tongueblock my overblows and overdraws I am forced to play them without using my tongue tip. Because of this I have to resonate better and this allows a softer attack on the note. I find that if I practice overblowing without using the tongue tip I can play my overblows much more relaxed. This makes them sound more like the other notes on the harp.

I never tongueblock in normal playing so I can't really say if it is practicle or not to play overblows with tongue block, but I do think that with a little practice it is perfectly possible to play overblows as well as, and maybe better than with a pucker.

Any thoughts on tongue blocked overblows?
A discussion on Harp-L showed there are just a handfull of people on the planet using them.
I started practising them this week as an experiment, but doubt very much that a high level of this technique is possible, compared to pucker overblows.
(Tongue blocking ofcourse does have many other benefits in "regular playing", I know)