MrVerylongusername
315 posts
May 19, 2009
9:02 AM
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I use plastic bodied harps - Lee Oskar's, Seydel's, Suzuki/Bushman. I hear LOTS of tonal differences between harps of different brands and models. I also hear differences when the same harp is played in different environment/conditions. I hear differences between the same harp recorded and heard by me whilst I'm playing it. I hear differences between players using the same brands of harp.
I've never said that Marine Bands do not have a different tone - THEY DO!
However...
I've pointed out - from a position of the physics of harmonica sound production and not the psychology of preference and expectation - that changes to the comb material do not appear to satisfactarily explain those differences. The suspicion is they come from elsewhere, my best guess is the acoustics of the coverplates (once you take account of different tunings).
I am a scientist, both by training and by how I approach life.
My current position is that by extrapolating my understanding of the mechanics at play, I have come to an informed best guess. I've posted at length in other threads what would be required to scientifically prove or disprove the debate, but it is beyond my resources, so I'm not going to do it - nor do I suspect will anyone else. Comparitive studies at any other level would only suggest whether further investigation was worthwhile.
If someone can show me SCIENTIFIC proof (i.e. evidence which eliminates all other variables and demonstrates replicability and validity) that there is a difference - I will happily change my stance. That's what scientists do when they cannot debunk the research of their peers (and peer review is a very important part of the scientific process).
People have posted links to 'research' which 'proves' the difference before. A 12 year old with a year's elementary science could have picked holes in the 'experiments' I've seen. I hate bad science. At one end of the spectrum they use it to sell shampoo on the other end it's what racist use to justify their intolerance. Bad science should be shown for what it is at every opportunity.
I'm not saying that the research you have cited is bad science, just that the situation are not comparable. The violin transmits vibrations of the string to the soundboard - soundwaves are created by the oscillation of that thin, flat and large surface (cf. a speaker diaphragm). They bounce around inside a resonating chamber to create harmonics and where the waves are focussed, by the shape of the chamber onto the soundhole and back onto the strings and neck to create a feedback loop. One cannot fail to see why the material of the violin wouldn't make a difference!
It's not just an issue of magnitude, the whole process is different. I cannot see what relevance it has to the physics of a free reed.
Hence my opening statement - apples and oranges.
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Philosofy
196 posts
May 19, 2009
9:39 AM
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Just remember that, in audiophile circles, there are some that swear you get better sound from a speaker by elevating the speaker wire off the ground. There are others that swear they can tell the difference in sound when different digital cables are used. So our debates here don't seem so far out in comparison.
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chromaticblues
83 posts
May 19, 2009
10:07 AM
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There is a thread here where I wrote in depth about testing marine bands and special 20's with marine band covers. Both of these harps have the same reeds with the same thickness reed plate. With the same tuning that I did with the same coverplates that I put on. Now I did this and found the difference to be quit noticeable, but that is with me playing!! And I know what I'm testing for. I'm a harmonica player that has had hearing test done every year. I am 46 years old and we have 20 to 25 workers hear every year. 19 of them are different each year. Most of these people are much younger than myself, but not once in six years has anyone had a high teat result than I have. I really didn't want to get into this, but the sounds that I'm talking about only a small percentage of people are capable of making! If you could hear me play something for you. Then you might be a little more understanding! Its one of those things that you youself would hear!! That is with me doing the test not you! Like I said I know what I'm testing! I know how to make them sound different is a better way of saying it.
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genesis
22 posts
May 19, 2009
12:00 PM
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Philosofy,
You hit the nail on the head. I recently sold a corian harp to a guy in my town and he didnt like the brightness. I told him to bring it over and I swapped the comb out for one made out of purpleheart exotic wood. The difference wasnt just subtle. It was night and day.
Even my wife said WOW! What a difference!She is not a player and doesnt pay attention to harps. People can debate this comb thing all they want but I trust my ears more than anything. Jason Ricci said on this forum a few months back " People that say combs dont make a difference need to practice more" Quoting from memory but thats pretty much what he said. He has told me this several times. Im sure you can do a search and find the quote. I believe denser materials increase the treble response. Some of that may have to do with taking great pains making a super flat comb. I lap all my combs on a lab grade, granite surface plate and polish them all way to 2500 grit wet or dry sandpaper.I then check them against a dial indicator to insure they are flat. They are also lapped on a roto lap. They use these in aerospace industry for gasketless mating of parts. Also for lapping of electronic silicon wafers.
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Patrick Barker
293 posts
May 19, 2009
2:59 PM
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Chromaticblues-
I'm not going to argue about whether or not wood actually makes a difference, but I'd like to clarify that in a violin the wood acts as a soundboard and the string's means of amplification, but in a harp the comb isn't meant for amplifying the harp's sound.
Cover plates, on the other hand, are meant for this, so cover plates are more comparable to the body of a violin.
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"Without music, life would be a mistake" -Nietzsche
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chromaticblues
84 posts
May 20, 2009
7:12 AM
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Yes Patrick your correct. This tonal change happens before that. I play SP20's with Marine Band cover plates and Marine Bands with MB covers. When playing unamped the difference isn't enough to worry about. I can't say for sure that it would be audible for anyone else to hear, but when amped with a high imp mic and one of my amps. The difference so noticeable that anyone that is into Chicago Blues would hear it immediately!
As far as the scientific explanation for Mr. longname. Higher frequencies have much shorter sign waves. The higher the note the more high end overtones are produced. It is these overtones that get broken up from the pours in the wood. The more porous a material, the more disruption of accurate note production.
Preston I would only go 1/16" taller and 3/16" from front to back. You will have to measure each model harp to see how much extra room you have before you have problems with the reedplate not covering the slot and/or the mounting holes in the plates not hitting wood when you get done. So you'll have take some apart and do that. Go as far as you can, but make it so it will go together afterwards!
Remember it's not how long from front to back the comb is. Your trying to extend the slots. Have the guy round the corners a little also.
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