Replies to This Discussion

Permalink Reply by Skeesix on July 18, 2010 at 12:36am

This sounds similar to how you would design a recording studio. If it's a normal room with right angles, there are dead spots where the sound waves cancel each other out. A square room is worse than a rectangular room. So what they do is build the room with oddly angled walls and ceiling.

I like the idea of putting the neck a little off center. Or maybe an internal baffle at a slight angle for one or more of the sides.

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Permalink Reply by Don Thompson on July 18, 2010 at 12:37am

Sounds more like a marketing niche he is looking for. Something to set his guitars apart from the herd. More profound differences would come from tone woods used and the type of bracing used. Bridge configuration, method of attaching the neck have be used to extoll the virtues of a maker's guitars,as well as other construction techniques. Then you have the question, what is a good sounding guitar? Is the reference standard a Martin Jumbo? An archtop jazz guitar? Since the box is being discussed offsetting the neck would have little effect on tone, the box hasn't changed.

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Permalink Reply by Don Goguen on July 18, 2010 at 12:44am

From my perspective as an audio systems designer, the statement is sort of correct but also rather incomplete. In other words, it is just not that simple.

In dealing with room acoustics, a square room where the ceiling height is a fraction (like 1/4 or 1/2) the width is the worse for sound performance. Rectangular rooms where the dimensions are not ratios of each other tend to sound better. The dimensions of a room have a huge impact on the performance of a sound system due to peaks and nulls specific in the rooms acoustic response. Put simply, the acoustic response is governed not only by the source (speakers) but also the room itself.

So how does this translate with cigar boxes? Just like a room, these boxes have there own acoustic response. Changing where the source point location (bridge) will affect the response at some frequencies for the better and worse for others but this is only within the acoustic range of the box. Any offset from center is usually done in the vertical dimension placement of the bridge. Ideal placement is done to maximize the resonance response or overall tone. This is where "art" come in. Finding what works sometimes takes trial and error.

I am sure there is a lot more going on with this guys build that has a greater affect on sound performance than offsetting the shape of the instrument. I would focus on understanding what else works and why before going down that route.

In support of my advice, look at the industry. Martin, Gibson and all the others. The overall design and shape of acoustic guitars has changed little over the years. Neck in the middle and a mostly symmetrical shape (both sides). With cigar boxes, we are dealing with a medium that has a myriad of limits due to acoustic issues related to size, shape and materials. These have a far greater impact on performance. I just don't think you are going to find any appreciable performance gain by going this route with a box shape instrument.

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Permalink Reply by MichaelS Country Boy Guitars on July 18, 2010 at 1:33am

This must be why cigar box guitars sound so great, the box's never seem to be perfectly square so they are asymetrical from the start!

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Permalink Reply by Paul Stephen Eklund on July 18, 2010 at 2:18am

Some cool responses. Thanks everyone for your impute!

Ya, there is a WHOLE lot more to the sound than just the shape. Guy goes into talking about wood grains, tonality, arching and on and on...He spends 1K or more just in woods. Lots of things that really wont apply to a cigar box. I was thinking the only part that we could try would be to offset the neck. Moving off center just by 1/8 would change the asymmetrical shape of the inside cavity. My uneducated guess would be to make the lower tone side the wider one.

I'm not one to be able to say ya or nay here cuz I still haven't been able to build my first one yet. Between the hours I'm working and the weather. Raining cats and dogs outside now. Not good for power tools. But one of these days...I got a Tshirt coming just so I'd feel like I was apart of things going on here. LOL

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Permalink Reply by Wes "I'm Baaaaack" Yates on July 18, 2010 at 3:27am

I suppose one could put a baffle or false wall inside the box to create asymmetry. I do have to say that, and NOT to disagree with any opinions prior or to come, but we are talking cigar boxes.

Very interesting thought tho!

-WY

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Permalink Reply by Mark Werner on July 18, 2010 at 4:52am

I think this idea may have more merit if the input was consistent. That is, if you only played one note. However, the input is far from consistent; we have different strings and different fretted notes, many of which are being played at the same time.
So the variables in the sound waves are going to be enormous. As the guys say, this sounds as much like "marketing speak" as anything to do with acoustic engineering.

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Permalink Reply by Frank Posey on July 18, 2010 at 5:44am

I'm sorry but I could'nt imediatly buy into this theory without some sort of science to backit up. I'm not saying it's not right but I've not found it to be true in any noticable degree in the things I've done. I think it's more about the woods, bracing and thicknessses and somewhat the luck of the draw when it all goes together.

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Permalink Reply by Outhouse Instruments on July 18, 2010 at 6:18am

Look at it this way ... we don't (usually) put our soundholes in the middle either.
In all honesty, if it were that actual and important all we would hear nothing but the sound from the strings.
Each sound has it's own frequency ( wavelength ). Even tho' all sound travels at the speed ... of .... sound ( I know) the freqencies number of waves change for the sound. So, all things being equal, it would all cancel itself out.

OK, Now ... we use rectangular boxes. Not equal.
Bridge NOT in the center.Nor equal.
Soundhole NOT in the center. Not equal.
The tension on the string actually changes as we pluck it.
The speed of string vibration actually constantly changes.
So the actual freqency of the string actually varies a bit.

You see where I'm going with this, doncha?


Matt

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Permalink Reply by Wes "I'm Baaaaack" Yates on July 18, 2010 at 6:30am

Luck o the draw.

-WY

Frank Posey said:

I'm sorry but I could'nt imediatly buy into this theory without some sort of science to backit up. I'm not saying it's not right but I've not found it to be true in any noticable degree in the things I've done. I think it's more about the woods, bracing and thicknessses and somewhat the luck of the draw when it all goes together.

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Permalink Reply by Outhouse Instruments on July 18, 2010 at 7:31am

For us ... yeah, luck o the draw.
Consider this. The hi E string is 329.63 Mhz ( this info is internet obtained, so your milage may vary)
This means that one wavelength ( the thing that "causes" frequencies ) is .36 ( 36 thousandths).
Harmonics would do exactly the same as the main, so you have a variation window of .36 to keep from having a shape that would allow cancellation.

Yeah, right.


Matt

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Permalink Reply by Paul Stephen Eklund on July 18, 2010 at 8:42am

Thanks again for everyones input. Boy am I glad this wasn't my idea. LOL

I only have one nice acoustic so I made a trace of it. Yep, both sides are identical. All I have is a Mid 70's Yamaha. If someone here has a Gibson, Marten or Fender be cool to hear if yours is also asymmetrical.

I'm not letting this idea die! Wrong? off the wall? Useless? I don't care! I like kicking a dead horse. JK LOL

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