Agree Art, I just need to spend more time on this, and I will! Renting some local studio time with a good engineer is something I really need to do at some point anyway, so I just may do that soon, I know it will be much better than anything I can do, plus I can get their opinion on the horns.
I am going to take another private guitar building class with Ian in February. I need a few more tips for the soundboard, and more importantly get some tips on a traditional (but large) soundboard if the one I made does not work.
I am also trying to talk him into building his own folded horn guitar, he seems interested. I would license it to him, and he can design his own version, manufacturing methods...he mentioned doing it with bent pieces (as I believe you mentioned earlier). I could help him with any CAD work he needs.
Plus he is considering buying a 3D printer to print some of his horn pieces and glue them together, to see if there is any cost savings, quality improvements, and or course the design freedom a 3D printer provides.
Art do you still have some of your recording equipment? I will swing by, and maybe invite Leo so you guys can give me some tips... 🤣 🤣
Thanks all! Joe
I am going to take another private guitar building class with Ian in February. I need a few more tips for the soundboard, and more importantly get some tips on a traditional (but large) soundboard if the one I made does not work.
I am also trying to talk him into building his own folded horn guitar, he seems interested. I would license it to him, and he can design his own version, manufacturing methods...he mentioned doing it with bent pieces (as I believe you mentioned earlier). I could help him with any CAD work he needs.
Plus he is considering buying a 3D printer to print some of his horn pieces and glue them together, to see if there is any cost savings, quality improvements, and or course the design freedom a 3D printer provides.
Art do you still have some of your recording equipment? I will swing by, and maybe invite Leo so you guys can give me some tips... 🤣 🤣
Thanks all! Joe
I have positioning marked for the soundboard to the body, and I glued the bridge to the soundboard. Dead nuts accurate, thought it may take a few tries. A glued piece floats around like a fish on water until it is clamped, I will take it!
Time to put some new strings on my guitar, always sounds so much better! Joe
Time to put some new strings on my guitar, always sounds so much better! Joe
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Having worked with many luthiers including some at Collings and Preston Thompson the first thing I would say is how the hell is the top going to vibrate? Second what math did you use to devise this and is the cutoff frequency even close to 81Hz (Low E)? I have a tractix and expo horn program I wrote decades ago in DOS and have made several back horns and at 50% length the tractix back horns in front of me for 40Hz are 4' high and 12" deep at the output.
I have several acoustics some real nice ones and weight is always an instant qualifier for how well it will sound. My PT is 3lbs and my Custom Colling C10-35 is 3.9lbs. All that extra wood is going to choke off the sound... also remember the throat on this should be at the bridge not the sound hole. That's the output!
Gordon
I have several acoustics some real nice ones and weight is always an instant qualifier for how well it will sound. My PT is 3lbs and my Custom Colling C10-35 is 3.9lbs. All that extra wood is going to choke off the sound... also remember the throat on this should be at the bridge not the sound hole. That's the output!
Gordon
Hello Gordon - welcome to the thread and thanks for the thoughts! I will be repeating some things I have said before, but not bad to do a recap, as I am thankful for getting many hits each week. I hope it is interesting, and fun.
This guitar has a double chamber, so the horns are the bottom chamber, and the soundboard rests upon the top empty chamber as usual, plenty of room to move. In fact the soundboard is light and strong (CNC), so I might get even more movement. As a backup idea, I can use a traditional Sitka Spruce soundboard, and that may sound better I know, so...I just don't have it fully assembled yet, I am close.
I am playing another acoustic guitar through this horn guitar to test sound and get measurements if you are wondering.
I do think CNC equipment has a place in guitar building, especially for a guitar with wild geometry like mine, to include the horns.
That said, hand made guitars are highly regarded, and for good reason. I would like to see this guitar made with CNC where needed, then go to the hand built stage to get the quality, fit and finish required for a fine instrument. Since this is a functional prototype, that might not happen on the first try, but that is the goal.
I saw a quote from a luthier, can't remember where: the body should be as rigid as possible, and ring like a bell, the top should move like a speaker, agree.
Do I think lighter guitars have great resonance that works in their favor, yes of course, there are many ways to get there, with an unusual guitar like mine.
DOS? Remember it well 🤣 Can I compete with your 4 foot tall horn, not a chance, I bet they sound great! Fitting two horns inside an acoustic guitar obviously has size challenges. As you know an 80 Hz wavelength is about 16 feet long. Using the 1/4 wavelength rule, I need a horn that is four feet long. I have two that are each five feet long. Of course I can't tune a large bell like you can with that size. I do have the driver chamber tuned at 125 Hz, and the full range speakers are rated at 150 Hz-20,000 Hz. Measurement data shows I am getting strong dB at 80 Hz and below, and seems to cutoff strongly at 50 Hz with the sweep, and slowly drops at 80 Hz with the horn guitar measurement.
I was not sure this would work, so I have done much testing, measuring, listening and sharing data. The first thing I did was play a song from my iPhone thru the speakers mounted in the horns, but uncovered, so no horns at all. Of course they sound like two 3" speakers not in a cabinet, not so great. Then I added the 1/2" Baltic Birch to cover the horns, and wow, the lows went through the roof, and the overall sound was great. I do have this before and after data posted earlier.
I am posting guitar horn/speaker system sweep FR, and also an REW measurement comparing a standard acoustic guitar (Guild) with my horn guitar.
My horn efficiency is great, (20, 30, some areas 40 dB higher) and the measurement output (comparatively) is flatter (stronger lows, similar strong mids, stronger highs). The acoustic guitar is a beautiful instruement with great tone, lets make it rock! Joe
This guitar has a double chamber, so the horns are the bottom chamber, and the soundboard rests upon the top empty chamber as usual, plenty of room to move. In fact the soundboard is light and strong (CNC), so I might get even more movement. As a backup idea, I can use a traditional Sitka Spruce soundboard, and that may sound better I know, so...I just don't have it fully assembled yet, I am close.
I am playing another acoustic guitar through this horn guitar to test sound and get measurements if you are wondering.
I do think CNC equipment has a place in guitar building, especially for a guitar with wild geometry like mine, to include the horns.
That said, hand made guitars are highly regarded, and for good reason. I would like to see this guitar made with CNC where needed, then go to the hand built stage to get the quality, fit and finish required for a fine instrument. Since this is a functional prototype, that might not happen on the first try, but that is the goal.
I saw a quote from a luthier, can't remember where: the body should be as rigid as possible, and ring like a bell, the top should move like a speaker, agree.
Do I think lighter guitars have great resonance that works in their favor, yes of course, there are many ways to get there, with an unusual guitar like mine.
DOS? Remember it well 🤣 Can I compete with your 4 foot tall horn, not a chance, I bet they sound great! Fitting two horns inside an acoustic guitar obviously has size challenges. As you know an 80 Hz wavelength is about 16 feet long. Using the 1/4 wavelength rule, I need a horn that is four feet long. I have two that are each five feet long. Of course I can't tune a large bell like you can with that size. I do have the driver chamber tuned at 125 Hz, and the full range speakers are rated at 150 Hz-20,000 Hz. Measurement data shows I am getting strong dB at 80 Hz and below, and seems to cutoff strongly at 50 Hz with the sweep, and slowly drops at 80 Hz with the horn guitar measurement.
I was not sure this would work, so I have done much testing, measuring, listening and sharing data. The first thing I did was play a song from my iPhone thru the speakers mounted in the horns, but uncovered, so no horns at all. Of course they sound like two 3" speakers not in a cabinet, not so great. Then I added the 1/2" Baltic Birch to cover the horns, and wow, the lows went through the roof, and the overall sound was great. I do have this before and after data posted earlier.
I am posting guitar horn/speaker system sweep FR, and also an REW measurement comparing a standard acoustic guitar (Guild) with my horn guitar.
My horn efficiency is great, (20, 30, some areas 40 dB higher) and the measurement output (comparatively) is flatter (stronger lows, similar strong mids, stronger highs). The acoustic guitar is a beautiful instruement with great tone, lets make it rock! Joe
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I started attaching my soundboard, will be (43) screws total, so it can be easily disassembled. With only (4) screws installed, I am getting a good feel for strength. I don't have evidence, but I know from experience, there is no way (43) screws are going to fail. Only (4) screws feels better than expected. I know for sure I applied way more than 4-6 lbs. per screw, this will work, soundboard is "sound" 🤣 OK sorry.
I wanted the soundboard to move like a speaker, I got my wish! Now I wonder: this will move big time compared to a spruce top. Looks like about 4 times as much distance. Will this deliver more SPL, sure! BUT, will it give me some crazy "whammy bar" type of movement that sounds terrible? I don't know!
I have some good graphics from my first few attempts at recording this guitar. Wow, it was clipping like crazy, I mean flat tops, bad! Thank goodness, I knew that terrible distortion was nothing close to what I was hearing. Will try again with recording level down. The problem is I need to have a level that can capture a regular guitar and the folded horn guitar, otherwise the comparison will be lost on others, stay tuned!
Still a little worried about feedback, but excited at the same time. There is a word for that. Life! Let's rock! Joe
I wanted the soundboard to move like a speaker, I got my wish! Now I wonder: this will move big time compared to a spruce top. Looks like about 4 times as much distance. Will this deliver more SPL, sure! BUT, will it give me some crazy "whammy bar" type of movement that sounds terrible? I don't know!
I have some good graphics from my first few attempts at recording this guitar. Wow, it was clipping like crazy, I mean flat tops, bad! Thank goodness, I knew that terrible distortion was nothing close to what I was hearing. Will try again with recording level down. The problem is I need to have a level that can capture a regular guitar and the folded horn guitar, otherwise the comparison will be lost on others, stay tuned!
Still a little worried about feedback, but excited at the same time. There is a word for that. Life! Let's rock! Joe
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I bought a couple expensive (well, to me anyway) acoustic Japanese Luthier built classical guitars recently. Both "boom" on the low/open A note, when tuned to concert pitch. I'm pretty sure if I measure them, I will find a peak in their top/body response right smack on A. That peak, is a quite similar thing as the series of peaks Art shows in the Hornresp Simulation.
Ideally, you want to tune these in a certain way to get it to sound like a good acoustic guitar. That would be something you'd have to ask your guitar building school comrade. I'm suspecting they should be flat to the concert pitches, as the guitars I have that are "on" or sharp to the A just dont sound as good to me. However I'm ignorant and for all I know a "good" classical acoustic booms on the A; I have two that do so. Just because I dont like it doesnt mean that's not the way it's supposed to be. I do know that a goal in a quality classical instrument build is that all notes play with reasonably even loudness.
I cannot come up with a technical explanation for why flat would sound / be better - save the guitar's response booming everytime you play a 1st position A or D. All I can think of is when a string is plucked, it does go sharp slightly and if you put a flat-tuned resonant filter on top of that...kinda like when you pull a note flat on a harmonica with your mouth cavity. What that does technically to the sound of the guitar is where my comprehension gets lost. The string's sonic input riding on the filter's "integrating" or low-pass side of the peak, versus the differentiating or high-pass side of the peak. Or smack on the peak...
I know some of these MLTLs are tuned just flat to the speaker resonance, to try to pull a smidge more bass out of the driver. The effectiveness versus consequences of such a design are debatable, I've seen. But that's a speaker, not a guitar.
As an aside, wood dries out over time, gets more stiff and who know what the tops of these two instruments did the day they left the workshop. Perhaps then they were flat to the A. 40+ years later, after who knows what environments they've been through; did the previous owner keep them properly humidified for all 45 years of ownership? Probability zero. So it's hard to say what the proper acoustic resonance state for a guitar actually is, just from these two examples. I do have others that dont do that.
Ideally, you want to tune these in a certain way to get it to sound like a good acoustic guitar. That would be something you'd have to ask your guitar building school comrade. I'm suspecting they should be flat to the concert pitches, as the guitars I have that are "on" or sharp to the A just dont sound as good to me. However I'm ignorant and for all I know a "good" classical acoustic booms on the A; I have two that do so. Just because I dont like it doesnt mean that's not the way it's supposed to be. I do know that a goal in a quality classical instrument build is that all notes play with reasonably even loudness.
I cannot come up with a technical explanation for why flat would sound / be better - save the guitar's response booming everytime you play a 1st position A or D. All I can think of is when a string is plucked, it does go sharp slightly and if you put a flat-tuned resonant filter on top of that...kinda like when you pull a note flat on a harmonica with your mouth cavity. What that does technically to the sound of the guitar is where my comprehension gets lost. The string's sonic input riding on the filter's "integrating" or low-pass side of the peak, versus the differentiating or high-pass side of the peak. Or smack on the peak...
I know some of these MLTLs are tuned just flat to the speaker resonance, to try to pull a smidge more bass out of the driver. The effectiveness versus consequences of such a design are debatable, I've seen. But that's a speaker, not a guitar.
As an aside, wood dries out over time, gets more stiff and who know what the tops of these two instruments did the day they left the workshop. Perhaps then they were flat to the A. 40+ years later, after who knows what environments they've been through; did the previous owner keep them properly humidified for all 45 years of ownership? Probability zero. So it's hard to say what the proper acoustic resonance state for a guitar actually is, just from these two examples. I do have others that dont do that.
JJ is back! Thank you my friend, I think I need to consider the tuning after the guitar is fully assembled, because until then, no good baseline for comparison.
After that, plenty of opportunity for tuning, changes, you name it!
I added more screws to the soundboard. If I had it to do over again, I would have CNC drilled all the holes in the body. I don't think that would work for the soundboard, as it is very thin, and can splinter easily. The best way of course, would be to drill everything together in assembly for a perfect match. Since I can't see the body wall when the top is on, not possible. To bad the top is not made of polycarbonate, then you could see everything, and it would be easy! 🤣
But of course that would sound like ****. 😉
There will be three times as many screws as shown now. I admit not pretty, but damn effective! Thoughts? Joe
After that, plenty of opportunity for tuning, changes, you name it!
I added more screws to the soundboard. If I had it to do over again, I would have CNC drilled all the holes in the body. I don't think that would work for the soundboard, as it is very thin, and can splinter easily. The best way of course, would be to drill everything together in assembly for a perfect match. Since I can't see the body wall when the top is on, not possible. To bad the top is not made of polycarbonate, then you could see everything, and it would be easy! 🤣
But of course that would sound like ****. 😉
There will be three times as many screws as shown now. I admit not pretty, but damn effective! Thoughts? Joe
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You "should" get one of those Dayton exciters like I have - it'll help you tune that soundboard. At least until someone writes a "TopResp" computer program, where you can just arbitrarily place brace parts in CAD and it calculates it for you.
Since your instrument is intended to be a self contained amplified thing, you can do some stuff with the soundboard bracing that other objectives wouldnt call for. Like an acoustic is ideally loud enough to fill an auditorium - hence the name of some guitars - and your soundboard doesnt have to do that all on its own. So, you dont have to make it as stiff, which means less - and less complicated - bracing.
One of my favorite sounding junkers, MIJ, has just 3 fans and another ones top bracing is more like popsicle sticks in the height of the braces. That Brazillian one has a nice deep tone to it.
This is again something to discuss with your luthier teacher; can you trade off less acoustic output from the soundboard for a smoother overall response, by not making it as stiff as would be called for on another design - one without amplification?
I take it you dont have a mile of room on the backside of that soundboard between it and the 1/2" thick top covering the horns chamber. As I think I said somewhere, might as well not even cut open the sound hole, as its output would be nothing like a normal acoustic having a normal body chamber volume. I have a Koa thinline that goes nice and deep, but it has a good 2" from the soundboard to the back of the guitar. Kala Uke Co - I dont know how they did it, response wise. Not cutting the sound hole also allows braces to cross in that area. I dont know how bracing is done on a guitar with the soundhole in the upper left corner, for example, but I bet it's different.
It'll be interesting to see what you come up with, if you're willing to share the design here. Hope my thoughts cheer you onward!
Since your instrument is intended to be a self contained amplified thing, you can do some stuff with the soundboard bracing that other objectives wouldnt call for. Like an acoustic is ideally loud enough to fill an auditorium - hence the name of some guitars - and your soundboard doesnt have to do that all on its own. So, you dont have to make it as stiff, which means less - and less complicated - bracing.
One of my favorite sounding junkers, MIJ, has just 3 fans and another ones top bracing is more like popsicle sticks in the height of the braces. That Brazillian one has a nice deep tone to it.
This is again something to discuss with your luthier teacher; can you trade off less acoustic output from the soundboard for a smoother overall response, by not making it as stiff as would be called for on another design - one without amplification?
I take it you dont have a mile of room on the backside of that soundboard between it and the 1/2" thick top covering the horns chamber. As I think I said somewhere, might as well not even cut open the sound hole, as its output would be nothing like a normal acoustic having a normal body chamber volume. I have a Koa thinline that goes nice and deep, but it has a good 2" from the soundboard to the back of the guitar. Kala Uke Co - I dont know how they did it, response wise. Not cutting the sound hole also allows braces to cross in that area. I dont know how bracing is done on a guitar with the soundhole in the upper left corner, for example, but I bet it's different.
It'll be interesting to see what you come up with, if you're willing to share the design here. Hope my thoughts cheer you onward!
I did my best to measure actual soundboard movement on a standard acoustic guitar. I don't have a dial indicator at home, but with a scale, it looks like the soundboard can move about .040" when pressed by hand, directly in front of the bridge. That does not mean it will move this much when played.
My guitar moves about .160" - 4X as much! I do not know if this will increase SPL, but I bet it does. My concern is, will it have a negative affect, with so much movement? I will know soon, anybody with experience in this area?
JJ - I still have your exciter in mind, just no time to even research this, but I am interested! Any data on how it performs?
I am now much more comfortable recording on laptop, def the way to go for me. I had recording levels higher than needed. Both guitars really need to be recorded at the same level, for each guitar, which hurts my comparison. I may just record mine and release it.
BTW - the big soundboard movement reminds me of a banjo, but no skin! I was listening to Muddy Waters in my shop, boy do I miss Chicago Blues bars, they rock! Joe
My guitar moves about .160" - 4X as much! I do not know if this will increase SPL, but I bet it does. My concern is, will it have a negative affect, with so much movement? I will know soon, anybody with experience in this area?
JJ - I still have your exciter in mind, just no time to even research this, but I am interested! Any data on how it performs?
I am now much more comfortable recording on laptop, def the way to go for me. I had recording levels higher than needed. Both guitars really need to be recorded at the same level, for each guitar, which hurts my comparison. I may just record mine and release it.
BTW - the big soundboard movement reminds me of a banjo, but no skin! I was listening to Muddy Waters in my shop, boy do I miss Chicago Blues bars, they rock! Joe
Yes. In my guitar collecting spree, I was dumb enough to buy two of the same model Aria classical acoustics. (I think I wanted a better "instance" than the first one I got) I sold the better of the two and shipped it today. Before packing it, I took my little transducer to task to see how the two instances of the same model guitar would measure. Pink noise, of course cause it's easy and fast...Any data on how it performs?
Here's the exciter just set on a different guitar's bridge; the rubber band keeps it from walking. Basically it's intended to drive into a wall, table top, hunk of foamcore - whatever you want to attach it to, to make that radiate sound. So why not at a guitar's saddle/bridge, to drive sound into it.
Using my measurement mic, here's how I made the measurements;
This is a different guitar, exploring a different idea, but I measured the two Aria classicals in pretty much the same way. Pretty much throw it on the bed, extend the mic stand as high as it will go and point the mic at the guitar.
So the leftmost peak, @~106 Hz, is the body cavity resonance. Block the sound hole with even a single layer of t-shirt material, that one goes away. The second peak, just north of 200 Hz is the first mode of the soundboard, where the whole board is moving up and down like a speaker cone. It makes sense that the "bass-reflex" part due to the sound hole "port" and body cavity are spot on, as it's the same model guitar. That the 1st mode of the top are lightly different, means - to my understanding anyway - that the wood has aged differently. God only knows what these two instances were subjected to in terms of environment, how they were handled - etc. But it's clear one has a higher Q than the other; it's more peaky for some reason. Perhaps its wood is more dry and stiffer.
The next peak is the second mode of the top, where two lobes at either side of the saddle are moving up and down, but out of phase like a see-saw. There, for some reason the response is again essentially identical. And so on until you get to the middle of the 1K to 2K octave, where they behave quite differently for some reason I'm not about to explain. Then they start to behave similarly again.
For what it's worth, the little 1/2 size guitar has a terrible peaky resonance on the D note, making it unplayable. It's a body cavity resonance. The experiment was to see if it could be dampened by use of an appropriate "resistor" which is a metal screen with an array of small holes covering the sound hole.
You can see the effect above. Here, I'm using band limited pink noise generated by REW and captured to a file, played back by the little SD card amplifier I use. It's almost a 6db damping, which you can hear when you play the guitar; the resonance is still there, but not as obnoxious. Even my wife who's just learning and can barely strum a chord wont play that guitar because its sounds so bad. Play any chord with a D - all you can hear is the D. Its better now. Or would be, if I can find a way to attach the "attenuator".
Edit - the reason I showed all this is apparently the method is repeatable, data collection run to run. I can move the drive to a different guitar, or run it a second time attached to the same guitar and get comparible results. It's a little trick to get set just right on the bridge - you have to hear that - but once you've done it a number of times, you know what to do.
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Cool, thank much JJ!
The nut on my guitar is custom and stepped, so it is free floating. Note sure that was the best idea, because now I have a custom nut that has to be fit. They file well, and can be cut with a small rotary blade, but a bit of a hassle, will get there.
I played the other night and thought what the heck happened to my FHAG sound? Then I realized the Baltic Birch chamber divider was not sealed, had it off the other day. Plus it did not have weight on top of it to hold, like I used to do, and that board was dancing on top of the horns, sounded terrible. The interesting thing is I could hear the vibration not just from the top of the chamber divider wood itself, but through the horns. I think that is a pretty good indication that the horn size/material/shape has a very large impact on the sound, and being hard maple, that is great.
When I played I put my ear directly adjacent to the horns, wow what a great sound. I know this is not a real world scenario, but interesting. I guess I could do that with two of them, or just use headphones! Wait - hornphones! 🤣
I do have my MixPad D.A.W. software pretty well figured out now. I get a .mpdp file from that, and can convert that to a .wav file, Then I can rename that a .pdf and post on DIY, then anybody obviously rename it to a .wav file and listen. I thought I would have something last night, but realized I was using my laptop mic by mistake (I had a clue when volume was the same with mic close and mic further away). So my setup was based on the laptop mic, which I don't want. Need to use the Shure SM57. It was getting late, so next time. Should not have a problem getting a good (?) recording to post now.
I have a private four hour class with Ian at Chicago School of Guitar Making on Friday, so I might not record until the weekend after. I need some tips about building an oversized Sitka Spruce soundboard, just in case my soundboard is not good enough. I will bring all my equipment and guitars (partial 🤔🤣) so he can hear everything live, and get his opinion. Plus he screws some of his tops on (some of the unusual guitars), can likely get some good info about that also.
He has shown an interest in building his own folded horn acoustic guitar, so hoping that goes somewhere. I will license it to him, easy. He only pays me after he sells guitars. I mean he builds custom horns, custom amps (mostly tube), and custom guitars, so my take: why don't you put all three in one instrument?! A great person and place to do this, with lots of experience with all three! I also offered to do any CAD work he needs for free. He does have a small CNC machine, pretty cool, but not big enough for this guitar body, but maybe the neck.
He would hand build most of it anyway, as it should be, see attached for some of his earlier work. Stay tuned and lets rock! Joe
The nut on my guitar is custom and stepped, so it is free floating. Note sure that was the best idea, because now I have a custom nut that has to be fit. They file well, and can be cut with a small rotary blade, but a bit of a hassle, will get there.
I played the other night and thought what the heck happened to my FHAG sound? Then I realized the Baltic Birch chamber divider was not sealed, had it off the other day. Plus it did not have weight on top of it to hold, like I used to do, and that board was dancing on top of the horns, sounded terrible. The interesting thing is I could hear the vibration not just from the top of the chamber divider wood itself, but through the horns. I think that is a pretty good indication that the horn size/material/shape has a very large impact on the sound, and being hard maple, that is great.
When I played I put my ear directly adjacent to the horns, wow what a great sound. I know this is not a real world scenario, but interesting. I guess I could do that with two of them, or just use headphones! Wait - hornphones! 🤣
I do have my MixPad D.A.W. software pretty well figured out now. I get a .mpdp file from that, and can convert that to a .wav file, Then I can rename that a .pdf and post on DIY, then anybody obviously rename it to a .wav file and listen. I thought I would have something last night, but realized I was using my laptop mic by mistake (I had a clue when volume was the same with mic close and mic further away). So my setup was based on the laptop mic, which I don't want. Need to use the Shure SM57. It was getting late, so next time. Should not have a problem getting a good (?) recording to post now.
I have a private four hour class with Ian at Chicago School of Guitar Making on Friday, so I might not record until the weekend after. I need some tips about building an oversized Sitka Spruce soundboard, just in case my soundboard is not good enough. I will bring all my equipment and guitars (partial 🤔🤣) so he can hear everything live, and get his opinion. Plus he screws some of his tops on (some of the unusual guitars), can likely get some good info about that also.
He has shown an interest in building his own folded horn acoustic guitar, so hoping that goes somewhere. I will license it to him, easy. He only pays me after he sells guitars. I mean he builds custom horns, custom amps (mostly tube), and custom guitars, so my take: why don't you put all three in one instrument?! A great person and place to do this, with lots of experience with all three! I also offered to do any CAD work he needs for free. He does have a small CNC machine, pretty cool, but not big enough for this guitar body, but maybe the neck.
He would hand build most of it anyway, as it should be, see attached for some of his earlier work. Stay tuned and lets rock! Joe
Attachments
You can also find the top main resonance with no microphone at all; just a resistor in series with the Dayton transducer and look at the pink noise spectrum across it. It'll be inverted, because at the frequency where it's easiest to drive mechanical force into the top, the current through the resistor will go down, therefore the voltage across it; I used 2 Ohm into the line input of my ADC box.
This is a cheap guitar with no saddle, just the plain top board awaiting a saddle replacement. Cute, eh? You can also find a speaker's free air resonance using this technique, which is what I was doing when I got the idea to try it on a guitar top with the Dayton exciter.
It's still a noisy measurement, but you can do it without a mic for tuning the top's 1st mode. No angles, no distances, no room reverberations - none of the usual indoor microphone measurement hoowey you have to think about. Think only measure, shave the braces down some, measure again. Or whatever it is Luthiers do to change the "main" resonant frequency of their top / brace design...
From out on the fringes,
That other Joe
This is a cheap guitar with no saddle, just the plain top board awaiting a saddle replacement. Cute, eh? You can also find a speaker's free air resonance using this technique, which is what I was doing when I got the idea to try it on a guitar top with the Dayton exciter.
It's still a noisy measurement, but you can do it without a mic for tuning the top's 1st mode. No angles, no distances, no room reverberations - none of the usual indoor microphone measurement hoowey you have to think about. Think only measure, shave the braces down some, measure again. Or whatever it is Luthiers do to change the "main" resonant frequency of their top / brace design...
From out on the fringes,
That other Joe
I finally have some .wav (.pdf) files, but of course they are too large to load on this site. Oh well, any suggestions? I did attach a .pdf showing recording levels.
I have a song with slow jazz chords to hear the guitar/horns, the same song but a little faster and harder, and also a slow finger picking song. They are not great recordings, but decent.
Art - you were right, I do have to EQ this guitar, but I have two EQ settings that work for these songs. Once I know where to go, not so bad. Maybe I can try a link to get this uploaded.
I bet JJ might have some ideas? Thanks! Joe
I have a song with slow jazz chords to hear the guitar/horns, the same song but a little faster and harder, and also a slow finger picking song. They are not great recordings, but decent.
Art - you were right, I do have to EQ this guitar, but I have two EQ settings that work for these songs. Once I know where to go, not so bad. Maybe I can try a link to get this uploaded.
I bet JJ might have some ideas? Thanks! Joe
Attachments
It's been a while, but when I had internet service in my name, I remember you got some file storage "space" as part of the deal. I used to host my ebay listing pictures there, guess it was before ebay could just upload them directly from your computer. Check with your internet provider, maybe it's as simple as you upload the files and then provide a link here. I think I've also used Google Drive here, to attempt to show what a couple of binaural recordings I made sounded like.
I still dont even know how to take a .wav file and add a static picture to it to make a movie file, like you see on youtube where someone just rips an artists album, uploads it with just an album cover picture showing for the whole 50 minutes of music...
I still dont even know how to take a .wav file and add a static picture to it to make a movie file, like you see on youtube where someone just rips an artists album, uploads it with just an album cover picture showing for the whole 50 minutes of music...
I took another class at Chicago School of Guitar Making, private class with Ian, was very helpful. Did some soldering that I needed help with, and also played a guitar through my horn guitar, plus many other detailed tips I need for fit, finish, wood strength. neck, you name it...was hitting 120 dB, sounded good even in a big room. Ian said my drivers and horns sounded clean, seems to be a marketable product. Next class will be guitar amp building kit.
One of the young interns took pictures, and said he and his friends really like this Folded Horn Acoustic guitar, very high interest level!
I wish I used CNC to drill the (48) soundboard holes in the body, while it was accurately setup on the machine, that would have worked well. Also drilling start "center punch" holes in the soundboard would also have been helpful (through holes no, too much risk of splintering).
I am enjoying doing it by hand, but with a blind match, it is taking much measurement layout, and only dare do 2-4 at a time, to assure they match with others already finished, it is taking forever. This is a great example of how CNC blows handwork out of the water, but NOT always, just in this case. Many other areas MUST be hand worked for quality - live and learn! 🤔
Ian played one of his guitars through some serious horns shown on attachment, those beasts could fill a gymnasium with sound, plus they rotate! His big horns are killer, too bad they don't fit in a guitar! 🤣
Stay tuned for link to recordings.
Art - I thought my laptop mic was not so great, BUT I was recording at too high of a level, after doing it right, not so bad.
When using my Shure SM57, I just can't get good volume on the recording. Is this mic better for live performance, and not recording? That does not seen right to me. I bought another one to to test, and also a Shure omni-directional. I am getting 120 dB from the horns, but the body can put out 90-95 dB also (but probably not carry far like a horn). So maybe an omni is better? Maybe I am doing something wrong 🤔. I will keep trying, but any advice you have would be appreciated. Thanks! Joe
One of the young interns took pictures, and said he and his friends really like this Folded Horn Acoustic guitar, very high interest level!
I wish I used CNC to drill the (48) soundboard holes in the body, while it was accurately setup on the machine, that would have worked well. Also drilling start "center punch" holes in the soundboard would also have been helpful (through holes no, too much risk of splintering).
I am enjoying doing it by hand, but with a blind match, it is taking much measurement layout, and only dare do 2-4 at a time, to assure they match with others already finished, it is taking forever. This is a great example of how CNC blows handwork out of the water, but NOT always, just in this case. Many other areas MUST be hand worked for quality - live and learn! 🤔
Ian played one of his guitars through some serious horns shown on attachment, those beasts could fill a gymnasium with sound, plus they rotate! His big horns are killer, too bad they don't fit in a guitar! 🤣
Stay tuned for link to recordings.
Art - I thought my laptop mic was not so great, BUT I was recording at too high of a level, after doing it right, not so bad.
When using my Shure SM57, I just can't get good volume on the recording. Is this mic better for live performance, and not recording? That does not seen right to me. I bought another one to to test, and also a Shure omni-directional. I am getting 120 dB from the horns, but the body can put out 90-95 dB also (but probably not carry far like a horn). So maybe an omni is better? Maybe I am doing something wrong 🤔. I will keep trying, but any advice you have would be appreciated. Thanks! Joe
Attachments
I think mics intended for recording a performance and those intended for recording voice or someone's guitar amp - like the SM-57 - are different beasts.Is this mic better for live performance, and not recording?
I think maybe you are correct JJ, I just received my Shure Omni, so I will try that, maybe I can get a better recoding. If not I will send the recording with the laptop mic. I have a Google Drive now, so I should be able to setup a link, then start sending out recordings, then maybe try different setups and send those also...it will be moving soon. Thanks! Joe
Microphones are tools, you need to choose the right tool for the work you want to do.Art - I thought my laptop mic was not so great, BUT I was recording at too high of a level, after doing it right, not so bad.
When using my Shure SM57, I just can't get good volume on the recording. Is this mic better for live performance, and not recording? That does not seen right to me. I bought another one to to test, and also a Shure omni-directional. I am getting 120 dB from the horns, but the body can put out 90-95 dB also (but probably not carry far like a horn). So maybe an omni is better?
Optimizing gain structure has nothing to do with the directionality of the microphone. If the SM57 does not provide enough level for your recording set up, it simply needs more pre-amp gain.
Omnis have smoother off-axis response than cardioid mics, but pick up sound equally in all directions, making isolation of the source more difficult. The sound of an omni won't change with distance as a cardioid will.
An omni will capture more room ambience, which can be good or bad.
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