Hello all - I have the second guitar body in process, much easier than the first, lessons learned. I tried more horn work,
but every time I make the horn smaller at the speaker, for more exponential growth along the entire horn, it losses SPL,
just does not work with the small dimensions I have to work with, based on guitar size. This is a truth I have discovered
three times now, and I know what to do, not this. The waveguide with only taper at the bell works, and sounds great!
I now have a battery powered amp (Roland) with 15 watts per channel, much better than the 5 watts per channel that
actually sounded pretty damn good and loud, will test tonight. My speakers are 20 watts, so need this! Ripping the guts
out of this and mounting inside the guitar will be more challenging based on dimensions, but thankfully circuit boards
are not large or heavy! The neck is being programmed for CNC cutting now, just need machine time. Stay tuned,
comments are very welcome, thanks! Joe
but every time I make the horn smaller at the speaker, for more exponential growth along the entire horn, it losses SPL,
just does not work with the small dimensions I have to work with, based on guitar size. This is a truth I have discovered
three times now, and I know what to do, not this. The waveguide with only taper at the bell works, and sounds great!
I now have a battery powered amp (Roland) with 15 watts per channel, much better than the 5 watts per channel that
actually sounded pretty damn good and loud, will test tonight. My speakers are 20 watts, so need this! Ripping the guts
out of this and mounting inside the guitar will be more challenging based on dimensions, but thankfully circuit boards
are not large or heavy! The neck is being programmed for CNC cutting now, just need machine time. Stay tuned,
comments are very welcome, thanks! Joe
Hello Rick, Art, PRR an all - another update attached. This amp will fit and sounds great. I have two 5" x 5" x 28" pieces of Rock Maple on the CNC machine now for two necks. We are very busy at work, but hopefully the programming will be complete next week, and then starting to cut wood. I know, sloooow.
Rick - I am especially interested in hearing more from you and others about feedback, my biggest worry. I noted earlier there is no way I can turn a mic up above four without it squealing, very bad, but at low volumes, OK. I can do this with 1/4" thick maple, no way with the typical .100" thick guitar wood.
I am also testing transducer pickups as noted earlier. Better, but still just OK. Quite frankly, they don't sound as good as I thought they might.
Piezo pickup under the saddle is another issue. Yes they do not sound great without an EQ, but using one helps. The biggest improvement is hearing them through the waveguides, they sound excellent though the waveguides, everything does, it is amazing. Whoever discovered the 1/4 waveguide rule is a genius, this guitar would not be feasible without the 5 foot waveguides. Two of them, stereo! OK I am not calling them horns any more, but they still taper out at the ends like a horn. I am submitting a new patent soon to cover both waveguides and horns.
Back to the feedback - I have aimed speakers directly as the piezo pickups under the saddle, and they do not feedback. Rick, why do you think I will have a feedback problem, I am not seeing this in testing.
I love hearing from you guys, I don't have anywhere near the experience you have, so your opinions are highly regarded, thank you! I am a problem solver, I do it at work in the automotive tooling industry every day, and I will do it with this project. My motivation is that I love to play guitar, and I especially love to hear music from the greats. Thanks! Joe
Rick - I am especially interested in hearing more from you and others about feedback, my biggest worry. I noted earlier there is no way I can turn a mic up above four without it squealing, very bad, but at low volumes, OK. I can do this with 1/4" thick maple, no way with the typical .100" thick guitar wood.
I am also testing transducer pickups as noted earlier. Better, but still just OK. Quite frankly, they don't sound as good as I thought they might.
Piezo pickup under the saddle is another issue. Yes they do not sound great without an EQ, but using one helps. The biggest improvement is hearing them through the waveguides, they sound excellent though the waveguides, everything does, it is amazing. Whoever discovered the 1/4 waveguide rule is a genius, this guitar would not be feasible without the 5 foot waveguides. Two of them, stereo! OK I am not calling them horns any more, but they still taper out at the ends like a horn. I am submitting a new patent soon to cover both waveguides and horns.
Back to the feedback - I have aimed speakers directly as the piezo pickups under the saddle, and they do not feedback. Rick, why do you think I will have a feedback problem, I am not seeing this in testing.
I love hearing from you guys, I don't have anywhere near the experience you have, so your opinions are highly regarded, thank you! I am a problem solver, I do it at work in the automotive tooling industry every day, and I will do it with this project. My motivation is that I love to play guitar, and I especially love to hear music from the greats. Thanks! Joe
Hello all - i just played George Szell Cleveland Orchestra Mozart Symphony No. 40 in G Minor through my iPhone into this Acoustic Waveguide Guitar body. I wanted to hear the difference from a rock song, WOW, not even close. I assume it is from the wonderful range of an orchestra, but the guitar body was vibrating like I could never feel it before, amazing. Cover the waveguides to close them, and BAM, cello, bass, oboe, drums... all join the music through 3" speakers. Before that it was all violins and violas. Every 1/4" thick wall of the guitar was vibrating big time, sounded wonderful, powerful. You can put your hands on it and feel it move! Stay tuned, still trying to get the guitar necks cut.
IMHO, there's no need to have the amp inside the guitar at your initial product offering, may be even advantageous to have it arranged for use with an external amp, a variety of which the player could choose from.
The novelty here (as I see it) is the sound emanates from the guitar itself, rather than an amplifier located elsewhere. From that perspective, the guitar's pickup (microphone) should be as isolated as possible from the sound producing, speaker and waveguide part. Because as we know, any mechanical / acoustic coupling will lead to feedback. The louder the instrument can play, without feedback, the better an instrument it'll be.
Looking at the waveguide arrangement, I see some pretty solid internal structure a string bridge could press against. A piezo element within that pressure force would transduce the string vibration into an electrical signal. The speakers as arranged could have a hard time putting any mechanical motion (vibration) into that solid, supporting internal structure taking the bridge force.
I think you can do it. Perhaps what I'm suggesting isnt what you have in mind. However, it seems the bits are in-place to achieve loud acoustic output without feedback, by giving the pickups a mounting that is mechanically isolated from the speaker system. The nearly opposed driver arrangement is good. The driver cone motion being orthogonal to the string / bridge force is good.
As you have money to spend on patent submissions and I know those arent cheap, perhaps its time to engage a professional luthier who knows exactly what they're doing when it comes to piezo pickups, string forces and non-microphonic mechanical designs of string bridges. I dont know who that would be, but there must be dozens of people around the world who have such skills and would be glad to sign an NDA to get to work with you on this!
I'd bet there's also more than one artist who'd like to point the neck of this instrument at their audience - and blast away.
The novelty here (as I see it) is the sound emanates from the guitar itself, rather than an amplifier located elsewhere. From that perspective, the guitar's pickup (microphone) should be as isolated as possible from the sound producing, speaker and waveguide part. Because as we know, any mechanical / acoustic coupling will lead to feedback. The louder the instrument can play, without feedback, the better an instrument it'll be.
Looking at the waveguide arrangement, I see some pretty solid internal structure a string bridge could press against. A piezo element within that pressure force would transduce the string vibration into an electrical signal. The speakers as arranged could have a hard time putting any mechanical motion (vibration) into that solid, supporting internal structure taking the bridge force.
I think you can do it. Perhaps what I'm suggesting isnt what you have in mind. However, it seems the bits are in-place to achieve loud acoustic output without feedback, by giving the pickups a mounting that is mechanically isolated from the speaker system. The nearly opposed driver arrangement is good. The driver cone motion being orthogonal to the string / bridge force is good.
As you have money to spend on patent submissions and I know those arent cheap, perhaps its time to engage a professional luthier who knows exactly what they're doing when it comes to piezo pickups, string forces and non-microphonic mechanical designs of string bridges. I dont know who that would be, but there must be dozens of people around the world who have such skills and would be glad to sign an NDA to get to work with you on this!
I'd bet there's also more than one artist who'd like to point the neck of this instrument at their audience - and blast away.
Hello JJ and welcome back, thank you much for the great feedback - pun intended! I can put the amp inside the guitar now,
ripped the motherboard and control board out of a great amp, it fits! The concept is to have it all in the guitar.
Agree, need a good Luthier, does anybody know of a good luthier in the Indianapolis/Chicago area that is interested?
I have talked to a few guys, and they are always unsure of the CNC part. but I have done that myself. Agree about isolated
pickups, seems to be OK now. Mic can only do so much, needs to stay at low volume OR just use piezo.
I am getting great sound from the driver positions as you note. I do not have money to spend on Patents, I learned how
to do them myself. The first one was a bitch, much time spent, after that, not so bad! When I finally get the build complete,
yes I will be looking for artists to help, but until I have a full guitar...waiting for necks to be cut on the CNC...waiting. Stay tuned!
ripped the motherboard and control board out of a great amp, it fits! The concept is to have it all in the guitar.
Agree, need a good Luthier, does anybody know of a good luthier in the Indianapolis/Chicago area that is interested?
I have talked to a few guys, and they are always unsure of the CNC part. but I have done that myself. Agree about isolated
pickups, seems to be OK now. Mic can only do so much, needs to stay at low volume OR just use piezo.
I am getting great sound from the driver positions as you note. I do not have money to spend on Patents, I learned how
to do them myself. The first one was a bitch, much time spent, after that, not so bad! When I finally get the build complete,
yes I will be looking for artists to help, but until I have a full guitar...waiting for necks to be cut on the CNC...waiting. Stay tuned!
I HATE !!!! the fact I did not think of this, I play guitar and would love to hear this it's a great idea. So very fricken cool !!!!!
Wow, thank you so much Sean! Stay on the thread and I will keep you and the group posted. It is taking forever due to doing this after work, and I work long hours. It is such a joy, I do not consider it work, and (thankfully) I don't care how long it takes, it must be right. This is bringing me more joy than money ever has, so money is part of the motivation, but the not the primary motivation. I love music and can't wait to play and hear this guitar!
Joe,
Since you are in the prototype/ proof of concept phase, simply buying a new or used guitar with a bolt on neck you could swap to your body could get you to that point in a few hours.
With an expenditure under $100 you can find electrics with a good maple bolt on neck.
The Indianapolis Music Go Round has several that might work, though they are asking around $150.
Art
Hello Art - yes, I thought about that myself, and I might do it, but I really want the neck I designed.
Since the guitar is longer, it really needs a big head stock so as not to look crazy. Also I need proof
of concept for the neck assembly, then bridge/saddle, then of course scale to nut, make sure everything
is to scale for pitch, then of course truss rod and neck straightness. I think I will wait, because once they start
cutting, it will be off the machine in a few days. That said, I might change my mind and go with your idea! Hah!
Since the guitar is longer, it really needs a big head stock so as not to look crazy. Also I need proof
of concept for the neck assembly, then bridge/saddle, then of course scale to nut, make sure everything
is to scale for pitch, then of course truss rod and neck straightness. I think I will wait, because once they start
cutting, it will be off the machine in a few days. That said, I might change my mind and go with your idea! Hah!
Hello everybody - some progress, and my take on engineered wood attached. Would love to hear opinions from all. Thanks! Joe
Would love to hear opinions about this: When I turn the bass up electronically through either the pickup preamp or the amp itself, it always becomes more distorted, Sounds more like an electric guitar at that point. But when I turn all the tone controls down, put the volume up all the way, and let the waveguides/horns do their work, WOW. The bass is through the roof, but zero distortion. WHY? It seems to me that acoustic bass improvement through wood itself just does not distort, but electronically, watch out. What say you? Thanks! Joe
Joe,
Sounds like you are clipping (distorting) the pickup preamp or the amp input's preamp, or both using too high of an input level.
A line level source output level could be +20dB (or more) above the -10 to -60dB level pre-amps are designed to accept.
Lowering the level of the input source will allow you to use the input and tone controls for the level they are designed for, (around -60dBu to -10dBu), rather than attenuation of signal.
Sounds like you are clipping (distorting) the pickup preamp or the amp input's preamp, or both using too high of an input level.
A line level source output level could be +20dB (or more) above the -10 to -60dB level pre-amps are designed to accept.
Lowering the level of the input source will allow you to use the input and tone controls for the level they are designed for, (around -60dBu to -10dBu), rather than attenuation of signal.
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Yes thank you Art, will do that. Thankfully my new amp has 15 watts per channel and plenty of volume, so lowering the preamp is doable.
Using an amp of lesser wattage and turning down the preamp just does not cut it. Not enough power to get the volume where it needs to be
for the horns/waveguides to work well. It seems to me the low frequency boast I am getting from the wood horns/waveguides is totally clean. not distorted in any way due to being acoustic and after speaker, not electronic and before speaker, correct??
I experimented with my 20 watt speakers last night, those little guys are really moving, pretty cool. That said when I test them out by themselves on the floor, quite frankly they are not impressive at all. When I test them mounted in the wood body, so much better. Then when I test them with the horns/waveguides covered by the chamber divider (1/4" thick Baltic Birch), but not held tight against them, we are talking a gap of a few hairs here, very impressive. But when I press hard to close the gap of just a few hairs, that is when the sound and especially the low frequencies go through the roof and makes every damn minute I put into this worth while, stunning sound for small speakers. Seems like enclosures, horns or waveguides in my case, must be closed 100% or it does not work near as well, what say you? Thanks for all your input Art! Testing more piezo under saddles and stick on transducers tonight. I now have some clip-on piezo's. I am going to use one on the guitar I am playing, and one on the folded horn/waveguide body to test feedback, have two channels in the amp. Also keeping mic on lower volume in the loop, I already know that will feedback over a volume level of four. Comments encouraged! Joe
Using an amp of lesser wattage and turning down the preamp just does not cut it. Not enough power to get the volume where it needs to be
for the horns/waveguides to work well. It seems to me the low frequency boast I am getting from the wood horns/waveguides is totally clean. not distorted in any way due to being acoustic and after speaker, not electronic and before speaker, correct??
I experimented with my 20 watt speakers last night, those little guys are really moving, pretty cool. That said when I test them out by themselves on the floor, quite frankly they are not impressive at all. When I test them mounted in the wood body, so much better. Then when I test them with the horns/waveguides covered by the chamber divider (1/4" thick Baltic Birch), but not held tight against them, we are talking a gap of a few hairs here, very impressive. But when I press hard to close the gap of just a few hairs, that is when the sound and especially the low frequencies go through the roof and makes every damn minute I put into this worth while, stunning sound for small speakers. Seems like enclosures, horns or waveguides in my case, must be closed 100% or it does not work near as well, what say you? Thanks for all your input Art! Testing more piezo under saddles and stick on transducers tonight. I now have some clip-on piezo's. I am going to use one on the guitar I am playing, and one on the folded horn/waveguide body to test feedback, have two channels in the amp. Also keeping mic on lower volume in the loop, I already know that will feedback over a volume level of four. Comments encouraged! Joe
Gross distortion from pre-amp distortion is easy to hear, even order harmonic speaker distortion is harder to detect- 100% second harmonic distortion of 81Hz (low E) will provide an equal level at 162Hz: "low frequencies go through the roof"...
Distortion should be low when the drivers are operating at an excursion below Xmax. Distortion is fairly easy to measure with REW (Room Equalizer Wizard).
As mentioned last August in this thread, REW includes tools for generating audio test signals, measuring SPL, impedance, and phase response plus many other features.
REW - Room EQ Wizard Room Acoustics Software
Small leaks can cause cancellation losses, as you have found by ear.
Art
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Thanks much for the link Art, looks really great. Not sure how, but I missed that in August, will review for sure. The distortion comments reinforce what I am hearing. Small leaks sure can cause cancellation losses, truly amazing how much, such a joy to learn about acoustics with an experimental product, way more complicated than I ever imagined.
Hello all - after hearing music from my iPhone blow the roof off these horns, and having a connected guitar do a pretty good job of this, I realized I needed an equipment upgrade. I had an OK piezo in the guitar, but then I got a Fishman. I think my previous was a China knockoff, did not sound bad. It is amazing what I will put up with until I hear something better. This Fishman is great, so much better tone wise! I have killed the volume problem long ago, it is great, but tone, is sooo much more important! Now the guitar itself is blowing the roof off, not just Allman Brothers and Mozart from my iPhone. I know I need to up my game on the Audio front. See attached for book I just received. How does it look Art and all? I l think it is great for me. Still waiting for the damn neck (2) to be cut. Lets Rock! Oh yeah I have good feedback info. I have placed piezo "discs" on the guitar I am playing, and also the guitar body with speakers. I get feedback very close to the speakers or course, only, all other areas no problem. I will make a design map for this later, my biggest worry (feedback) is slowly digressing. YES!!
Good audio books can be a help, if you are interested in recording, the one you chose should get you started!
Hello all - picture attached for neck, not complete, but close. The goal was to have a bit of a convex shape, and when the strings
apply about 150 lbs. of force, that will bring the neck to a straight position, we shall see, truss rod will adjust!
Now that my volume is killing it, I had some time to work with tone. New Fishman under saddle sounds really great with the correct amount
of master volume, keep the bass low, not needed with horns that provide killer bass. I am still getting 115-120 dB max, amazing.
Still need to add mic with pickup, next.
I mentioned before, but holding this guitar in your arms with an iPhone pumping music through it, I can feel the power through the vibrating wood body,
you can actually feel the speakers pumping into your body, fricking amazing. Play with a drop D sixth string, and that damn string sustains for so long if played open, wow, you only have to hit it about 25% as much as normal through a song.
When I play the final cord or notes, they sustain for easily 30 loud seconds without touching the guitar, never heard anything like it. I am not just trying
to sell my product, it is true. Art can you help me with frequency response measurement at hopefully +/- 3 dB. Best way to measure this?
I know what it is from the amp specs, but how do I measure my instrument. I know it sounds great but I sure would like to have some data to
back that up. Thanks! Joe
apply about 150 lbs. of force, that will bring the neck to a straight position, we shall see, truss rod will adjust!
Now that my volume is killing it, I had some time to work with tone. New Fishman under saddle sounds really great with the correct amount
of master volume, keep the bass low, not needed with horns that provide killer bass. I am still getting 115-120 dB max, amazing.
Still need to add mic with pickup, next.
I mentioned before, but holding this guitar in your arms with an iPhone pumping music through it, I can feel the power through the vibrating wood body,
you can actually feel the speakers pumping into your body, fricking amazing. Play with a drop D sixth string, and that damn string sustains for so long if played open, wow, you only have to hit it about 25% as much as normal through a song.
When I play the final cord or notes, they sustain for easily 30 loud seconds without touching the guitar, never heard anything like it. I am not just trying
to sell my product, it is true. Art can you help me with frequency response measurement at hopefully +/- 3 dB. Best way to measure this?
I know what it is from the amp specs, but how do I measure my instrument. I know it sounds great but I sure would like to have some data to
back that up. Thanks! Joe
If the measurement is at one meter in free space (outdoors), that would be loud.
Sound drops at 6dB for each doubling of distance, 120dB at 31mm (1.2 inches) would be only 90dB at one meter (39 inches).
Sympathetic vibration is very typical for acoustic instruments, surprised you haven't noticed the effect before.
The loudspeaker acoustic vibrations are in synchronization with the instrument string vibrations, a form of acoustic feedback.
If acoustic gain is increased a bit more, sustain will become infinite in length, a little bit more gain and the string vibration feedback loop will increase to the point where they require muting to not progressively "take off".
You can use REW freeware for measurement, and may be able to use your dB meter microphone:
https://www.roomeqwizard.com/
I'd second REW. You'll need a measurement microphone, which is something you'd probably want to have on hand anyway, given the scope of your effort so far. The USB ones, such as miniDSP UMIK-1 or Dayton UMM-6 would save you having to fool with a separate USB interface using a more ordinarily connected microphone.