JJ and Art - you guys have never let me down, thanks for all the good comments, I need to revisit my theory, I know I do not have enough evidence, just observation. I am going to tape a dB meter to the top of the chamber divider so I can see the output reading through the sound hole, that will tell a story with horns off and horns on.
JJ- the chamber divider is screwed on with (12) screws, that way I can remove it easily.
I am interested in this so I can understand of course, but I also want to use this for marketing, if I can prove what is happening, needs to be accurate. If I am not getting as much power from the chamber divider as I think, then maybe my horns are working better than I expected. If I can get that much power, so clearly while playing, from horn mouths that don't have the best directivity to the guitar player, that would be good news, stay tuned!
JJ- the chamber divider is screwed on with (12) screws, that way I can remove it easily.
I agree with your above comment Art, but I am going to measure dB for a good first step, regarding how much power is coming from the horns and into the hollow body/upper chamber. I can't image the chamber divider does not provide anything, it must, it is vibrating. I know this because back in the day (before my first guitar was complete) I would play a standard acoustic guitar through my horn body. I could literally stand on the chamber divider and body, and feel a pretty damn good amount of vibration through my feet.
I am interested in this so I can understand of course, but I also want to use this for marketing, if I can prove what is happening, needs to be accurate. If I am not getting as much power from the chamber divider as I think, then maybe my horns are working better than I expected. If I can get that much power, so clearly while playing, from horn mouths that don't have the best directivity to the guitar player, that would be good news, stay tuned!
I'd say that construction method doesnt well represent what would be done in production, with everything finalized. Any effect you're getting from a looser-the-glue coupling to the routed body portion may be just a prototype anomaly.
That said, chunks of wood can be tuned to resonate at concert pitch and harmonics thereof, so it is conceivable that the divider board could be, say, tightly suspended on felt strips and allowed to ring between the horn channels and upper chamber, while maintaining an air tight seal.
That would be some bit of mechanical alchemy to tune that piece to ring at a concert pitch, such that the guitar "comes alive" when you tune it up. Like an old Gibson SG I once owned did; it "liked" being tuned to standard concert pitch. You could feel it in the guitar and hear it in the sustain of the sound it made. I had a little Gibson acoustic that did it also. They knew how.
For sure JJ, as you know I do not like glue for this guitar, but yes a proto should be as close to production as possible.
OK don't laugh at my crude setup below. Day off tomorrow, so I have time to experiment tonight.
Now the above idea I really like! Never thought of that, in my head now! And yes Gibson knows mucho, that is why I want to sell it to them or Yamaha.
OK don't laugh at my crude setup below. Day off tomorrow, so I have time to experiment tonight.
JJ and Art:
Per above setup, I strummed my guitar at the same level ("medium") for horns off and horns on. Of course I would get different dB levels as I go, the meter was pretty much up and down by +/-10 dB depending on if it was directly during strum, or slightly after strum and sustaining.
That said, I focused on the max dB for both, so I have some consistent data:
Without horns max = 106 dB
With Horns max = 122 dB
One meter away would never sound this loud, with just a "medium" strum, so the dB meter in the guitar would be misleading by itself, but for an apples to apples comparison I think not bad. Thoughts?
Per above setup, I strummed my guitar at the same level ("medium") for horns off and horns on. Of course I would get different dB levels as I go, the meter was pretty much up and down by +/-10 dB depending on if it was directly during strum, or slightly after strum and sustaining.
That said, I focused on the max dB for both, so I have some consistent data:
Without horns max = 106 dB
With Horns max = 122 dB
One meter away would never sound this loud, with just a "medium" strum, so the dB meter in the guitar would be misleading by itself, but for an apples to apples comparison I think not bad. Thoughts?
A dB meter won't tell you anything regarding frequency content, other than the difference seen when weighting is changed from none to "A" or "C". "A" rolls off the response below 1kHz.
Using REW's pink noise through the amp/speakers, you could get a baseline frequency and level at various position near the horn exit. Identify each, and save them.
Move the mic to other positions you hypothesize are contributing to the horn's output.
Then dampen the movement of the sound board by hand or with foam pillows to determine it's influence.
Cover the sound hole, etc.
Save each for comparison.
Any small air gap can leak sound waves directly through them.
Vibration you feel with your feet would probably be much lower than frequencies that contributes to guitar output.
Using pink noise, you can see the relative output in various locations.
Substituting a piezo transducer for the test mic, you could measure the wood vibrations at different locations independent of air transmission.
You have not used accurate measurements of the horn's output before, but they would be interesting to see.
Do you expect the 1/2" chamber divider is leaking much output from the horn channels?
I still think "data" that varies by two orders of magnitude with the signal used to produce it is useless.
Art
Thank you for the good feedback Art, I still think seeing a higher dB level with the horns tells a story, not frequency data I agree, but the power is there, I can hear it, I knew it. I am finally going back to my second guitar build. I have been limping along on that one because we finally put our house on the market Saturday, moving back to Chicago. That was a good three months of repairs and updates on a big old house build in the 1880's, but still in mint condition.
A few weeks ago I had some time to fit my new Sitka spruce soundboard, and my neck to the body, and my custom nut, everything was going great. The neck was dead nuts on, but I put my hand on the headstock and felt it move, I was like what the **** is that? Found a crack from the bottom of the nut pocket into the neck. Wouldn't you know it, one of the few places I have a sharp corner in the wood. Rookie mistake, happened when I was fitting the nut with a tight press fit, then gradually into a slip fit, all on me. The F bombs were flying! 🤣 Thankfully I can repair it with glue and clamping. I actually saw a video of a guy that glued on a headstock that was completely snapped off the neck. That is pretty dicey!
Your comment about not using accurate data: I am not going into that again, we had this argument before, I just don't agree with you, let's leave it at that.
Anyway thank you Art and JJ, tonight I have a two hour jam session planned, that is where the rubber meets the road, so much fun!!
A few weeks ago I had some time to fit my new Sitka spruce soundboard, and my neck to the body, and my custom nut, everything was going great. The neck was dead nuts on, but I put my hand on the headstock and felt it move, I was like what the **** is that? Found a crack from the bottom of the nut pocket into the neck. Wouldn't you know it, one of the few places I have a sharp corner in the wood. Rookie mistake, happened when I was fitting the nut with a tight press fit, then gradually into a slip fit, all on me. The F bombs were flying! 🤣 Thankfully I can repair it with glue and clamping. I actually saw a video of a guy that glued on a headstock that was completely snapped off the neck. That is pretty dicey!
Your comment about not using accurate data: I am not going into that again, we had this argument before, I just don't agree with you, let's leave it at that.
Not sure why you think my data is "data". It is a measurement that confirms what I observed. Sure it is all over the place, what would you expect from a dB meter inside a guitar. During strumming and after strumming is quit different dB. What is important is one had a lower +/- 10 dB range and the other had a much higher +/- 10 dB range. This is not surprising, and it tells a story of power output, hardly useless.
This I admit I don't know. 😉
Anyway thank you Art and JJ, tonight I have a two hour jam session planned, that is where the rubber meets the road, so much fun!!
Jam session last night was fantastic. Just for fun, my Website is staying steading with hits, CA has by far the most hits of any state, bless their hearts. These are the CA cities/towns that are tuning in:
Glad to hear it! Open mic was fun too, got to do 4 songs. "Fly Me To The Moon", "Georgia", "Beyond The Sea" - take me another year to get past tripping up at some point on that one, "Alone". Love the chord changes in "Fly Me To The Moon" and "Georgia". Hang with the other performers. Talk US politic without leaving a trace - left the phone in the car.
You might try the pink noise as the FR test source sound. Let the octave or fractional octave band analysis results cards fall as they may.
Doesnt really matter, as long as you and some hefty customer base like how it sounds - as is. Analysis of the results can only lead to suggestions on how to make it a little bit better, if possible.
JJ did you play guitar AND sing Georgia? If you did, you have balls! I love Ray Charles, who doesn't?
Right now I am thinking if I find a serious buyer, my suggestion will be: take this guitar wherever you want, play it, get others to play it, get some measurement data until the cows come home, take the damn thing apart if you want, make improvements if you want, do whatever, as long as I can put it back together. Then let me know what you think, let her rip!
Right now I am thinking if I find a serious buyer, my suggestion will be: take this guitar wherever you want, play it, get others to play it, get some measurement data until the cows come home, take the damn thing apart if you want, make improvements if you want, do whatever, as long as I can put it back together. Then let me know what you think, let her rip!
I did. The Chorus is a little troublesome still. I ripped Willies version off YT to practice to. Whatever it is that I sing, isnt anything like how he does it. Same with the Sinatra song. Those guys are phrasing their vocals all over the place and I prefer to glide through the words, which I suppose makes the song a lot more boring to listen to. I'm a rank amateur at it and I'll continue as long as I can sing in key, its fun to do and I seem to be getting better as the years go by. An hour a day as Ray recommends is difficult to pull off, even as a retired guy!
JJ - kudos to you for playing these great songs on guitar, and singing! I remember that you are retired, didn't you work for Intel? If so, did you ever get the pleasure to meet Andrew Grove?
Art - I checked the internet, and see mixed results as usual, but I prefer going right to the source 🤣 Do drivers really have a warm up time, and get better after warm up? Is this accurate or a myth?
Art - I checked the internet, and see mixed results as usual, but I prefer going right to the source 🤣 Do drivers really have a warm up time, and get better after warm up? Is this accurate or a myth?
A blanket statement won't apply to all drivers equally.
That said, changes due to heating are not mythical.
"Better" is a subjective term that really can't be applied to changes.
While there are many driver parameters that may change slightly as a speaker warms up, each parameter affected results in different changes, the changes sum together into more complex outcomes.
For woofers, the suspension may initially need to be stretched ("broken in", like shoes..), it's free air resonance (Fs) will be higher than rated until that happens. After "break in", there still can be a difference in compliance between a "cold" and "warm" suspension.
Different materials used in each driver react differently to heat.
The vast majority of the power applied to a driver is converted to heat rather than sound, causing the voice coil temperature to rise over time.
Smaller, lighter voice coils heat up faster than larger ones, and the heat exchange from voice coil to magnet structure and air can be vastly different depending on pole piece and spider design, whether the driver is in a vented or sealed enclosure, and the enclosure volume.
As the voice coil heats, it's impedance becomes higher.
Amplifiers make less power into a higher impedance, so a hot voice coil may see half (or less) the power of a cool one, causing "thermal compression".
In a guitar speaker, thermal compression may subjectively sound better, especially if the player prefers the sustain and tone of an over driven amplifier without too much SPL.
Speakers with tiny voice coils in a tiny sealed compression chamber like you are using in the FHAG are a near worst/best case scenario for thermal compression.
In a speaker used for sound reinforcement, as the speaker delivers less SPL as it heats, the operator will tend to push the amp, mixer (or both) into clipping (or limiting) to make up for the loss.
Amps driven into hard limiting or clipping deliver more average power.
The more average power used, the more thermal compression, a spiral that can burn the voice coil.
In a speaker using a passive crossover, it's frequencies and slopes shift as the driver's impedance changes, which will certainly sound different, usually worse.
Art
Wow, there is a lot going on with drivers, thanks Art! They may be considered inefficient, but they are pretty remarkable of course. Inefficient compared to what? Other sources of sound that are much better? 🤣 OK horns improve efficiency, we like that.
Do my drivers sound better with time, say after an hour of playing? Maybe, certainly nothing I can prove.
Now the drivers, horns, soundboard, strings (new), intonation, amp and any guitar player getting more comfortable as they go, does that get better over time? I am pretty sure the answer is yes, but that may also be true of a standard acoustic guitar. The longer you play, the more comfortable you are, still not anything I can prove, but I like it!
What would worry me is if it sounded pretty much the same after you warm up, or God forbid, it sounded worse. What if the guitar intonation was not consistent, and sounded worse over time due to some unforeseen problem with the guitar itself (screwed on soundboard). Who knows what else could have happened with a guitar built at work and home by a "Luthier in Training".
My buddy that is going to help me with the live testing in a big room through a PA says he really wants to hear this. He has good mics for the horns and also wants to hear it direct, let's give it a go!
This week my fourth Patent (attached) was published for my Acoustic Waveguide Grand Piano. The USPTO only published it because by law they must publish after 18 months. Granted is next, and I hope it will go through!
Do my drivers sound better with time, say after an hour of playing? Maybe, certainly nothing I can prove.
Now the drivers, horns, soundboard, strings (new), intonation, amp and any guitar player getting more comfortable as they go, does that get better over time? I am pretty sure the answer is yes, but that may also be true of a standard acoustic guitar. The longer you play, the more comfortable you are, still not anything I can prove, but I like it!
What would worry me is if it sounded pretty much the same after you warm up, or God forbid, it sounded worse. What if the guitar intonation was not consistent, and sounded worse over time due to some unforeseen problem with the guitar itself (screwed on soundboard). Who knows what else could have happened with a guitar built at work and home by a "Luthier in Training".
My buddy that is going to help me with the live testing in a big room through a PA says he really wants to hear this. He has good mics for the horns and also wants to hear it direct, let's give it a go!
This week my fourth Patent (attached) was published for my Acoustic Waveguide Grand Piano. The USPTO only published it because by law they must publish after 18 months. Granted is next, and I hope it will go through!
One thing that has been proven is the ear's stapedial reflex, and how it contracts in response to loud sounds, protecting hearing.
A temporary hearing threshold shift (TTS) in response to SPL over ~85dB can occur over a short time period, recovery takes time after the sound has reduced. TTS can be well over 10dB.
You may have noticed the TTS effect when you find your car radio blasting the morning after returning from a loud concert.
The radio didn't seem near as loud as the concert, but after the TTS wears off, ouch..
How much your particular hearing changes compared to how much the drivers change would require separate measurements.
The driver's response changes are easy to measure, and repeatable.
Your TTS in response will vary with the stimulus type, length of exposure, how tired you are, mood, what you ate, medications, alcohol, and maybe even the phase of the moon.
TTS makes it difficult to parse out the changes in a speaker (or tube amp) over time "by ear".
Art
No question about that Art, I have experienced it many times, pretty cool.
One of the features I like about my guitar is turning the horns off and on at will.
Play with them off, standard acoustic guitar for the most part. Turn them on and BOOM! Then get used to the sound over time, does not seem as loud as when immediately turned on, so just turn them off, BOOM! in the opposite direction., a very stunning difference!
When playing with them on, over long periods of time and after you are used to it, just seems to get better. I think that may be in my head also, and fun things just seem to get better as you do them.
My hope is others will experience this same phenomena, and also enjoy it to the point of, wow, this is very different, and much better than what I am used to hearing coming from an acoustic guitar!
I say buy your strings in bulk, they are every bit as good, and much less expense. I have never had a problem with them. Especially important for people that like to change strings often, as I do. You just can't clean off the finger oil and sweat, degrades sound!
But, you didnt say where to get them. Are they Martins? Martin direct? Can you get any of their string "models" this way, or only the "Authentic Acoustics"?
JJ - I bought mine from JustStrings.com, pretty happy with them. I have seen reviews good and bad, so buyer beware. Shown below are (12) packs, but mine still have about (15) strings of each left, so I bet I bought approx. (25) in a pack, but I can' t find that many now.
I like Martin strings also, you can get these in bulk from Sweetwater. Plus I just saw the Ernie Ball Earthwood strings that John Mayer is backing this morning when I was browsing through AGM, looks interesting, I might try these. I am kind of a John Mayer nut, so that got my eye, boy is he one hell of a fantastic musician. Not only is he a great singer/songwriter, he plays a seriously mean guitar! No wonder chicks dig him!
I like Martin strings also, you can get these in bulk from Sweetwater. Plus I just saw the Ernie Ball Earthwood strings that John Mayer is backing this morning when I was browsing through AGM, looks interesting, I might try these. I am kind of a John Mayer nut, so that got my eye, boy is he one hell of a fantastic musician. Not only is he a great singer/songwriter, he plays a seriously mean guitar! No wonder chicks dig him!
Guitar #2 neck is fixed, that got my attention. I put a wedge into the neck crack, pried it open, prayed it would not crack, and filled it with Titebond. I clamped it tight for 24 hours, worked great! Next is find a nice stain color that will look good with black screws on the soundboard. This guitar will have the same great sound, and hopefully look good this time!
