Artificial Strumming machine

[jody_cruzan]

Hi All,
I've been strumming in some nice mandolins with a strumming machine I built.
The Results have been fairly dramatic and I wondering if you guys have any
idea what is actually happening to the sound boards to realize these dramatic
improvements. I'm especially interested in the opinions of people that have
actually done some break in / de-damping procedures.

Reference: 30 rpm gear drive is producing 1 strum per second and strum times
range from 160 to 300 hours. We're talking a lot of strumming.

Thank you all for your time and consideration

Regards,
Jody

[Barry Platnick]

can you post a picture of the MandoBot?

[jody_cruzan]

Hi Barry,
I have some pics. Let me see if I can figure out how .....

I don't see how to attach a picture. If I email you a couple of pics, would
that help? and/or can you post them??? Sorry, this is my first time to
post. Hopefully I can figure some of this out

Thanks
Jody

[jody_cruzan]

OK Barry,

Here we go. I hope they are attached.

Thanks
Jody

[Larry S Sherman]

That's pretty impressive. I especially like how your clamps adjust.

I'm actually in the middle of building one of these myself. I got the motor, voltage regulator/speed changer, and I've built the clamps. My next step is the base and pendulum arm.

I was wondering what you're using as a pick? Are you using an actual pick, or a credit card or something similar?

Thanks, Larry

[charlesa46741]

Very nice--are your plans available?

[jody_cruzan]

Hi Larry,
I'll try to attach a picture of the pics I've been using. It seems that regular
old pics work the best, but I have to glue them between some maple veneer
so the clamp can grab them solid. It also gives us a little wiggle room and
safety room for the slight differences in mandolin thickness, bridge height etc.

This is the 5th one I've built and they are getting a little better. By the way,
credit cards and motel room key cards seem to break real easy.

Thanks
Jody

[jody_cruzan]

Hi Charles,
I don't have any plans. On this one, I just sketched it out, full scale on the
floor of my garage. I wasn't having any luck trying to calculate anything. I'm
pretty sure that I shouldn't be admitting to my un-intelligence. If it would help,
I might could take some pics with some rulers or yard sticks in the picture for
some reference. These things are kind of troublesome to make and I haven't
really made one good enough to sell, but I do like having them around. Many
people ask me to strum their mandolins for them, but it's easier and safer to
loan them a $400 strummer in stead of me worrying about their "trillion dollar"
mandolin. It will also drive a person nuts after 3 or 4 weeks of one strum per
second.

[Larry S Sherman]

Can you tell me how long the pendulum arm is?

Do you find that you are getting a uniform strike pattern against the strings with your current design? I'd like to benefit from your experience if I can.

Larry

PS: I'm excited that there are other geeks out there playing with these machines!

[martinedwards]

why?

what's the point?

[jody_cruzan]

Hi Larry,
I don't have the machine here right now, but I'll get over and try to measure
it. It seems that to hit the strings the best, the pendulum needs to be centered
over the E strings. I guess because these strings are usually the lowest on
flat and radius fret boards.


Mr. Edwards,
I'm not sure I understand your question(s). Sorry about that.

Regards,
Jody

[Larry S Sherman]

why?

what's the point?

Are you asking the point of de-damping?

I think it's an interesting topic.

[Larry S Sherman]

Hi Larry, I'll get over and try to measure
it. Regards, Jody

Hi Jody,

Thanks. I hope I haven't hijacked your thread too much. I hope that people who have more experience answer your original question.

Thank you, Larry

[Steve Davis]

How would you describe the difference in sound before/after?

[foldedpath]

I've been strumming in some nice mandolins with a strumming machine I built.
The Results have been fairly dramatic and I wondering if you guys have any
idea what is actually happening to the sound boards to realize these dramatic
improvements.

Before theorizing about how this is causing "dramatic improvements" it would be nice to verify that it's happening. Human memory of sound isn't all that reliable. That gadget is ideal for hooking up a good quality microphone at a fixed distance, and making a recording before and after the process. Make the first recording with a new set of strings after a few hours of auto-strumming to break them in. Then after a period of de-damping, put on another set of strings, break them in for the same period, and then make another recording with the same mic, same mic distance and angle, same preamp levels, etc.

Then post the recordings online as uncompressed .wav files (or FLAC) and use randomized file names with the file creation dates reset. Post a separate text file that identifies the files. Then people can do a blind, ABX comparison to see if any difference can be heard.

The same process can be used to test other ideas like blasting an instrument with a speaker playing music at close range and high volume, or physical vibration. An auto-strum gadget like this is ideal to remove the variable of the human player when making a test recording, so you're already most of the way there. Aside from demonstrating that it does something positive, ABX listening tests could also help pin down the amount of time needed for best results.

If a majority of people do hear a significant tonal improvement in a blind listening test, then I think we could all agree that this process is worth doing. Otherwise we're back to anecdotal evidence and confirmation bias (i.e. it's natural to want to believe that a process works, when you're spending time and money on it).

[jody_cruzan]

Hi Steve,
I would describe the instruments as louder, more responsive, improved overall
tone. All 16 instruments I've been involved with where described this way by
all parties involved. I'll touch on Mr. FoldedPath's, great response in a minute.
The oddest thing everyone (all 16 without exception) reports is that the
mandolins are easier to play. I understand this one the least.

I've been pursuing this for about 4 years now. What started me on this road
was being told that all instruments open up (?) and improve when have been
played for a couple of years. I assumed that this was universally accepted,
but I may be mistaken. I may be wrong, but I think what was implied was that
they had to be played and not just sitting in the case for two years. I may
be wrong about that.

Now, I like Mr. Foldedpaths response very much. Maybe my question should
have been do instruments open up, can we prove this, and if they open up
and "sound better" (we would have to define this), Then maybe I can ask
what is happening to the sound boards to realize this improvement.

It's kind of late now, but I was inquiring about this information so I could
maybe assist or amplify the improvements I'm hearing. I thought maybe it
might help to warm or cool the room, lower or higher humidity, etc... just
trying to gain understanding. I haven't really understood anything since
about 1977, but I thought I would give this a try.

Thanks Mr. Foldedpaths for your great response. (And the other responses
as well)

Regards,
Jody

[SternART]

I've had good success with Roger Siminoff dedamping some of my instruments. I have a good ear and it has worked!!!! especially to balance out the pairs of strings. One mando had killer bass, but a weaker E string. I got it back much improved from Roger, but intuitively felt it still had more......sent it back a second time.......now the E string rocks, is in balance with the other courses, and I'm so glad I didn't sell this instrument. Roger does more than just strumming, he measures resonant frequencies of top, back, tone bars, and blasts the specific frequency to excite various parts of the instrument. You can read more on his web page.

I bought a book titled "How to Improve the Resonance Conditions of Musical Instruments by Vibration-Dedamping" written by Prof. Gerhard A. v. Reumont. I learned that this dedamping is more common in Europe and with violin family instruments. I thought it was interesting to read of its use after repair of cracks to the really vintage instruments where wood has been added to reinforce.....to vibrate & break in the repair. I think it is an interesting technique, and after doing 4 instruments myself as experiments, I "know" it makes improvements. It has been significant on 2 of the 4 examples I have done, with more moderate improvement on the others. I think some instruments are just tight, and possibly just whuppin' on them for 20 years will loosen them up. BUT...... I can appreciate speeding up the process, especially if you have a coupla instruments to play in.

[MikeEdgerton]

It should also be noted that Roger Siminoff's de-damping service does not simply strum the instrument, it is but one part of the process. It should also be noted that you can't make a silk purse out of a sow's ear.

[jody_cruzan]

Thanks Mr. SternART,
I agree with you on Mr. Siminoff's process. I think the "sonic blasting" he does
is an awesome process since he can tune to the exact frequency of specific
parts of the instrument. I'm surprised how affordable this service is. I would
also like to point out 300 hours of continous strumming should knock the "new"
off of any instrument. I'm not sure I would pay for a "de-damping" service, but
I think a few guys could go in on building them a strummer and not be dis-appointed with the results.


Mr. Mike,
You are right about that. I've built 14 mandolins and none of them sounded
as good as a sow's ear. LOL I've noticed on low end mandolins (and especially
low end guitars) this strumming business really helps these instruments. I'm
wondering if they are a little over built just to minimize warranty issues and
for some reason there is just more wood to loosen up???? Not sure.

Thanks All.

[jody_cruzan]

Hi Mr. FoldedPath

I've been reading your response again and while I'm not going to completely
dismiss my own experience and the opinions of many others I respect on the
results of strumming, You really have me thinking now about the process you
are describing.

I'm not sure if it's OK to ask you this on this thread, but do you think with a
strumming machine, could we evaluate strings, bridges, bridge height / string
loading? Even though we would still be using human beings to evaluate the
sound/tone, the "blind" part of testing really appeals to me. The mandolins
don't really sound very pretty, but with some clever capo's we could generate
chords and such. What do you think???

Thanks again
Jody

[mandopete]

Can this be far behind?

[mandopete]

...and I got scared when I saw the banjo!

[mandopete]

...and this one (though it's not real) reminds of the Pikasso guitar built by Linda Manzer that's played by Pat Metheny.

[jody_cruzan]

Hi MandoPete,
I'm not sure what your trying to say or ask. Are these some machines you've
built or use? If so, are you having any positive or negative results? They look very cool but kind of complicated.

Thanks
Jody

[EdSherry]

Jody -- The first is listed on the Web (YouTube) as a device at MIT. The second is identified as a "robot guitar" -- a "musical machine" that mechanically plays various instruments, plucking the strings and fretting the neck to make music.

The YouTube listing for the second video says:

"ragtimewest.com designs, builds and sells robotic musical instruments of all types. Check out this video of an automated guitar playing with a banjo!"

Back around the turn of the (last) century, they used to make quite a few such "mechanical jukeboxes," though not as sophisticated as the second one shown.

The last video, marked "not real", is a computer animation.