A Test Rig for Assessing Tonal Properties of Solid Body Electric Guitar Construction

[mistermikev]

hearing sm thing in celery top vs tas... first few hits... I don't know that it is necc desireable or undesireable but the front of the note is varying quite a bit on the low e.

first one ramps up... second one has lots of vol right away.  it is possible that if you trimmed them you perhaps trimmed off the front of the note. 

 

looked at them in edison and they are indeed very different.  the downward spike on the first one is neutered... and the volume tapers off the maximum spike fairly linearly(if that IS a word) whereas the second one sort of holds for two spikes and then drops off.  doesn't look like they were truncated at the front like I was thinking.  no idea what this means... just observed. 

[curtisa]

Personally I can hear really subtle differences between some of the timber pairs when they're played back to back. But they're super-borderline, to the point where if I went out of the room for 20 seconds to put the kettle on and came back, if I started playing one sample at random I'd never be able to tell what I was listening to. They're certainly not the earth-shattering differences some people claim to be able to hear when comparing identical guitars made from different timbers.

[Bizman62]

9 hours ago, curtisa said:

the time taken for the note to decay to an absolute dB value.

Your English is better than mine, that was what I was thinking of.

 

9 hours ago, curtisa said:

18 hours ago, Bizman62 said:

Five species would make - what - ten different pairs? Would that be too much to ask?

I reckon you'd lose perspective with so many choices at your disposal, and the relevance to the sound produced when plugged in seems somewhat tenuous.

Guess so... Then again, having the sounds in pairs as either one single long file or five separate duos might help getting the idea of the acoustic differences. Clicking separate files include the mouse click and the time needed for that which might be enough to forget part of the sound. My idea was a ten pair file containing one time pairs as follows:

1. Tas Oak-Radiata Pine - pause
2. Tas Oak-Celery Top Pine - pause
3. Tas Oak-Blackwood - pause
4. Tas Oak-Kauri Pine - pause
5. Radiata Pine-Celery Top Pine - pause
6. Radiata Pine-Blackwood - pause
7. Radiata Pine-Kauri Pine - pause
8. Celery Top Pine-Blackwood - pause
9. Celery Top Pine-Kauri Pine - pause
10. Blackwood-Kauri Pine

That list would cover all variations, the rest would be same woods in different order which may not be relevant

[curtisa]

One string of each or three of each? One pair of each implies a single example string of each, in which case - which string? Bearing in mind that it's been suggested that the differences seem to become hard to hear depending on which string is played.

Hint: the wound strings are easier to make last longer when strung/tuned/detuned/restrung...

[Bizman62]

3 hours ago, curtisa said:

One string of each or three of each

Ouch! Didn't remember the three strings! Of course all three would give more perspective regarding the tonal range of a guitar but in order not to stress you too much, would the wound D string be a good compromise?

[mistermikev]

8 hours ago, curtisa said:

Personally I can hear really subtle differences between some of the timber pairs when they're played back to back. But they're super-borderline, to the point where if I went out of the room for 20 seconds to put the kettle on and came back, if I started playing one sample at random I'd never be able to tell what I was listening to. They're certainly not the earth-shattering differences some people claim to be able to hear when comparing identical guitars made from different timbers.

well for the record... my comments... wasn't trying to say that indicates a 'qed'.  that said... differences that are small can be insignificant to some but everything to others... just a matter of perspective.  further... I think little differences can accumulate on a guitar build.  every component makes some difference and I think folks often will conflate the summary of those differences with one single difference.  I've done it myself... put a pickup in two guitars and hear a difference and try to point to one single difference (wood type) between those two guitars as the culprit.  

[Crusader]

I haven't read all the conversation but I used to compare pickups a lot, and what I found is my hearing wasn't always the best. After doing comparisons for hours I couldn't tell the difference between a Neck Pickup and a Bridge

[curtisa]

7 hours ago, mistermikev said:

I think little differences can accumulate on a guitar build.  every component makes some difference and I think folks often will conflate the summary of those differences with one single difference

By and large I agree, but the results I seem to be pulling out of this experiment may suggest that the wood used makes such little difference in and of itself that it could be completey disregarded as a contributing factor.

It may raise the possibility that people who claim to have swapped a rosewood neck for a maple neck on their Strat, noticed a change in the sound and attributed it to the rosewood are incorrect. That given it takes them 30+ minutes to do the swap, unless they go to the trouble of making recordings before and after and comparing the results in a very clinical manner they may be imagining they're hearing a change. Or, if there is indeed a measureable change that perhaps they should be looking at something else other than the rosewood as the reason why it is different.

Same may also apply to people who are building a guitar and chosing timber expecting it to sound a certain way. Chosing alder due to the expectation the result will be 'snappier' may be false. Chosing mahogany becuase the result is expected to be 'warmer' may be false. That chosing a piece of wood based on how it sounds when struck may be pointless.

[mistermikev]

25 minutes ago, curtisa said:

By and large I agree, but the results I seem to be pulling out of this experiment may suggest that the wood used makes such little difference in and of itself that it could be completey disregarded as a contributing factor.

It may raise the possibility that people who claim to have swapped a rosewood neck for a maple neck on their Strat, noticed a change in the sound and attributed it to the rosewood are incorrect. That given it takes them 30+ minutes to do the swap, unless they go to the trouble of making recordings before and after and comparing the results in a very clinical manner they may be imagining they're hearing a change. Or, if there is indeed a measureable change that perhaps they should be looking at something else other than the rosewood as the reason why it is different.

Same may also apply to people who are building a guitar and chosing timber expecting it to sound a certain way. Chosing alder due to the expectation the result will be 'snappier' may be false. Chosing mahogany becuase the result is expected to be 'warmer' may be false. That chosing a piece of wood based on how it sounds when struck may be pointless.

i suppose then all your future builds will be out of pine then?  you are convinced?  hehe.  

my interpretation of the results is a little dif.  I think what I saw there in those two waves either suggests that your testing equip was introducing a variance that would render the test results somewhat invalid, or it has shown that there is some amount of difference. I suppose I could spend a bunch of time looking for patterns of that anomaly in other waves... but I'm not entirely motivated since I think even if it were proven to me -beyond a shadow of a doubt, that there is zero dif between maple and mahog... it would make a very small difference to me in terms of what I would choose to build with.

attaching things like "little" or "big" to that difference are sort of subjective and meaningless imo because little to you may be big to someone else.  IMO the best we MAY be able to say is there is or is not a difference, again, imo. 

like many of the other tests I've seen... by themselves they don't say too much - I haven't seen one that has PROVEN to me one way or another.  you have to keep adding them together and take the leap of faith that is siding on one summary or another.  For the record either side is reasonable.

I think afa luthiers go... even tho I don't believe necc that maple is def going to be brighter... I think you have to make some judgements about the wood.  making a guitar out of mdf with a steel neck - I've made the judgement that that combo probably doesn't have a lot of probability of sounding good.  making an entirely maple guitar?  sure, I'd do that... but I think I'd probably have some backup plan for the pickups.  would I expect an all mahog guitar to sound warmer than an all maple guitar - I would... but then I wouldn't be surprised if it was the opposite.

[curtisa]

5 hours ago, mistermikev said:

i suppose then all your future builds will be out of pine then?  you are convinced?  hehe.  

Would that be so bad if that were the case?

Realistically we'll continue to build our guitars out of whatever we feel like. Even if the stats suggest that tonally it makes no difference, that completely disregards what we or the paying customer may want aesthetically. A slab of pine will never be a substitute for the appearance and/or feel in the hands of spalted maple.

And the other side of the 'wood matters' debate that this experimental test rig cannot solve is that the knowledge that you are playing a piece of mahogany, either by being able to see it, feel it or be reliably informed that it is in the guitar by some other means, may influence how you play the guitar, which in turn could change the tonal output.

 

5 hours ago, mistermikev said:

I suppose I could spend a bunch of time looking for patterns of that anomaly in other waves... but I'm not entirely motivated since I think even if it were proven to me

That was primarily why I didn't want to provide screenshots of spectrum analysis and instead only focus on the sounds. There's no real advantage in trying to see the difference if you can't hear it, or trying to find the visual reason why sound A does sound more bassy than sound B. We don't play guitars by looking at the output jack.

The other way I think we should all be approaching it is asking ourselves, 'how likely would I be able to have heard the difference if I didn't have the comparison handy in such a clinical and controlled fashion?' If the answer is 'pretty unlikely' then perhaps the argument raised by some people that wood matters almost insignificantly holds more water than we give it credit.

 

5 hours ago, mistermikev said:

attaching things like "little" or "big" to that difference are sort of subjective and meaningless imo because little to you may be big to someone else.  IMO the best we MAY be able to say is there is or is not a difference, again, imo. 

I would probably use the qualifier 'detectable' to any assessment of a guitar's output based on these recordings, rather than 'big' or 'small'. Most players know what a 12-month old set of strings sound like and don't need to hear something to compare it with to know the strings sound worn out. You probably couldn't say the same thing if you were asked to assess a set of strings 24 hours old and say whether they're 'brand spanking new' or '1 day old'. To me this is where wood A vs wood B sits - I think the difference needs to be much bigger than what's in these recordings to be able to categorically say that a choice in timber based on species alone can make or break an electric guitar from a sonic point of view. If all the differences are really tiny they'll get lost in the noise, even if they do stand out when played side-by-side through the magic of audio editing. In reality it takes us 15 seconds to unplug the alder Tele and plug the pine one in - how much of our memory of what the first one sounded like 15 seconds ago can we rely upon?

[Bizman62]

3 hours ago, curtisa said:

Even if the stats suggest that tonally it makes no difference, that completely disregards what we or the paying customer may want aesthetically

Exactly that! The looks is what always has made me drool over a guitar, the price tag having been the limiting factor. Wasn't it Muddy Waters who said that he may not be the best blues player but he's got the nicest suit so at least there's something pleasant for the eyes...?

[mistermikev]

7 hours ago, curtisa said:

Would that be so bad if that were the case?

Realistically we'll continue to build our guitars out of whatever we feel like. Even if the stats suggest that tonally it makes no difference, that completely disregards what we or the paying customer may want aesthetically. A slab of pine will never be a substitute for the appearance and/or feel in the hands of spalted maple.

And the other side of the 'wood matters' debate that this experimental test rig cannot solve is that the knowledge that you are playing a piece of mahogany, either by being able to see it, feel it or be reliably informed that it is in the guitar by some other means, may influence how you play the guitar, which in turn could change the tonal output.

 

That was primarily why I didn't want to provide screenshots of spectrum analysis and instead only focus on the sounds. There's no real advantage in trying to see the difference if you can't hear it, or trying to find the visual reason why sound A does sound more bassy than sound B. We don't play guitars by looking at the output jack.

The other way I think we should all be approaching it is asking ourselves, 'how likely would I be able to have heard the difference if I didn't have the comparison handy in such a clinical and controlled fashion?' If the answer is 'pretty unlikely' then perhaps the argument raised by some people that wood matters almost insignificantly holds more water than we give it credit.

 

I would probably use the qualifier 'detectable' to any assessment of a guitar's output based on these recordings, rather than 'big' or 'small'. Most players know what a 12-month old set of strings sound like and don't need to hear something to compare it with to know the strings sound worn out. You probably couldn't say the same thing if you were asked to assess a set of strings 24 hours old and say whether they're 'brand spanking new' or '1 day old'. To me this is where wood A vs wood B sits - I think the difference needs to be much bigger than what's in these recordings to be able to categorically say that a choice in timber based on species alone can make or break an electric guitar from a sonic point of view. If all the differences are really tiny they'll get lost in the noise, even if they do stand out when played side-by-side through the magic of audio editing. In reality it takes us 15 seconds to unplug the alder Tele and plug the pine one in - how much of our memory of what the first one sounded like 15 seconds ago can we rely upon?

"would that be so bad" well... no, of course not.  I thought about my own comment quite a bit tho... and it def depends on the pine... but most pine doesn't hold a screw or take stain well.  iow there are a lot of good reasons to use 'tonewoods' that seldom get considered.  I would liken it to the 'great capacitor debate'.  some folks are adamant that you should never use anything but 'little greenies'.  In my own mind (i use a lot of wima) I think there are a lot of good reasons other than tone to use fancy caps.  how long they last, resistance to temp, consistency (ie not having to measure each cap)... and then look.  I don't see anything wrong with using mojo parts if for no other reason than to have a cool 'look'.  

how likely to hear... well... I have to assume there are folks out there that can hear much better than me.  fully acknowledge that I highly doubt I could tell you what sort of wood some guitar was based on a recording - esp after we add overdrive/eq/fx.  that said, and speaking to your placebo point, it might only matter that the player feels some difference.  ie, lets say that wood does make a difference, but it is not detected by the pickup... I think that would ultimately influence the player.

detectable - well said.  I do agree... that thinking you can predict the sound based on wood is silly.  That said I don't think there's anything wrong with trying to factor in wood choice and make some assumptions about the effect it might have on overall sound.  I think the shame comes when you start thinking "this guitar can't sound good because it has pine in it".  or "this guitar won't sound good because it doesn't have mahog".  that said... I think going fwd I'll have to fight the urge to think a concrete guitar isn't going to sound great.

alder vs pine tele.  both have made awesome teles... "hot rod lincoln".  pine really should be accepted into the hall of tonewood fame!

also of note: I think one-day-old strings of mine might be discernable.  I have long had the super power of being able to corrode strings very quickly.  I am crazy fanatic about wiping my strings down and keeping my hands clean... but between a few guitar playing friends it is quite documented... if I touch a string - come back a day later - black spot.  i kid you not!  my band mates always half-joked that they didn't want me playing their instruments - esp the bass player.  

that said... can we calculate the amount of days old where strings sound bad? no... so we all make the assumption that new strings will sound better.  I don't think that is all that different from the 'error on the wise side' we do in choosing a 'tonewood'.  that said... again, I would not subscribe to the tonewood nazzi prescription that only maple/alder/mahog/walnut sound good.  my def of tonewood includes just about everything. maybe not bulsa (hehe).

[Crusader]

In 2008 I bought a Les Paul Studio and I always thought the higher notes around the 7th fret sounded 'raspy.' Then several years later I upgraded to a Traditional and it sounded much nicer in that area. However I made the mistake of keeping the Studio and was able to compare them at home. I discovered that the Traditional had absolutely no 'bite' in the bass. I just did not like that at all and sold it again losing $1000

Before I sold it though I bought a LP Axcess then the 59 Reissue, so I had 4 Les Pauls and an ES-137, and they all sounded different. Whether you could pick them from a recording or not is another thing. To me its more about how it sounds while you play

But never mind all that. I often wish I had just kept the Studio and bought a new van!

[Bizman62]

1 hour ago, Crusader said:

To me its more about how it sounds while you play

Is that more about how it feels on your body or the actual sound? I mean, isn't a recorded sound similar to the sound coming out of a speaker? Is it possible to actually hear the sound in a gigging situation?

[Crusader]

47 minutes ago, Bizman62 said:

Is that more about how it feels on your body or the actual sound? I mean, isn't a recorded sound similar to the sound coming out of a speaker? Is it possible to actually hear the sound in a gigging situation?

While you are playing a guitar it is 'live', when you listen to a recording it is 'done' (if you know what I mean)

Yes I can hear the sound in a gigging situation, for example the ES-137 sounded great on its own but to me it just didn't sound right in the mix and it put me off. However another guitarist might have thought it sounded fine. And I don't think the audience would notice one iota

[Bizman62]

I mean, can you hear-hear the guitar during a gig, not just from the speaker but also through your bones or whatever it is? As you said, the ES sounded great on its own but not in the mix which might tell that within the solo sound you were 'hearing' more than just the electric sound while in the mix it was more similar to a 'recorded' sound if the band distorted your physical connection to the instrument.

After reading the above I'm not sure if you can understand a word I'm saying. I'm not sure if I understand it myself!

[mistermikev]

2 hours ago, Bizman62 said:

I mean, can you hear-hear the guitar during a gig, not just from the speaker but also through your bones or whatever it is? As you said, the ES sounded great on its own but not in the mix which might tell that within the solo sound you were 'hearing' more than just the electric sound while in the mix it was more similar to a 'recorded' sound if the band distorted your physical connection to the instrument.

After reading the above I'm not sure if you can understand a word I'm saying. I'm not sure if I understand it myself!

i think there is a lot of truth to that.  I've made recording with a 335 that looking back I would have sworn was a strat... but it was somewhat inspiring while I was playing it... that said... if you play at break neck volumes all that goes out the window.

[curtisa]

As per @Bizman62's suggestion, below are the averages of the three string plucks of each of the three strings for all five timber species. Each of the common string pitches were level-matched for the initial peak so that they all started from the same relative level. A noisegate was applied to each sample, adjusted to cut the tail off automatically once the level decayed to -50dB. The resulting files could then be easily checked to see how long they were.

Interesting to note that   sustains for the wound strings vary quite a bit between species, but for the plain strings they're all nearly identical. Whether that variance would become noticeable when played in a real life situation is unclear.

All the strikes of the one string within a single timber species are pretty much the same (worst case variance is Blackwood low-E; 9.98sec - 10.84sec), which suggests that the robo-picker was capable of operating fairly consistently

 

[Bizman62]

Now that's interesting!

Supposedly the wound strings have a longer sustain simply because they have more mass (energy) to make the wood vibrate in a manner that makes the string vibrate - something similar to the Newton's Cradle where you can't get much of an effect if the starting ball has only a fraction of the mass of the other balls in the row.

Does the sustain correlate with Elastic Modulus or Specific Gravity? The Wood Database didn't know many of the woods so it's not easy to tell. I tried to compare the specs for Blackwood, Radiata and Kauri and could not find any explaining correlation. Then again, we can't be sure how well your pieces match with the WD test pieces.

Could we read from the chart that the Celery Top Pine would make some interesting basses?

 

[curtisa]

4 hours ago, Bizman62 said:

Does the sustain correlate with Elastic Modulus or Specific Gravity?

I'd have to get back to you on that.

Note that the heavy/denser timbers (blackwood and tas oak) had shorter sustain in the bass, whereas the lighter 'piney' woods (although not necessarily pines as such) had stronger sustain in the bass. Given that blackwood is a close cousin to koa, itself a relative to mahogany, that seems somewhat at odds with conventional wisdom that says mahogany should be stronger in the bass than tighter-grained timbers. While I don't have any maple to play with, both celery top and kauri have very tight grain and high stiffness that would normally be associated with maples, which in turn are meant to accentuate the highs. The sustain figures here contradict that expectation, as there appears to be no appreciable difference on any of the high-E's across any of the example species.

[mistermikev]

fantastic work.  this hat is delicious and yes, I will be building out of pine from here on out.

[Bizman62]

5 hours ago, curtisa said:

Note that the heavy/denser timbers (blackwood and tas oak) had shorter sustain in the bass, whereas the lighter 'piney' woods (although not necessarily pines as such) had stronger sustain in the bass.

That was my first thought but then I looked at the Radiata Pine which is on par with Blackwood at the low E and the weakest at D. Looking at the Elastic Modulus and Specific Gravity the Radiata Pine is quite similar to Kauri Pine, both of which differ noticeably from the Blackwood so the "piney" factor just doesn't seem to correlate. By specs the two pines were similar, by sustain the Blackwood and Radiata were similar on the Low E.

The Wood Database didn't have specs for Tas Oak or Celery Top Pine no matter whether using the scientific or common name. And even for the three found there I couldn't read the Specific Gravity right, I thought it was a decimal comma but I just noticed that it separates values of green and dried wood.

I just came out of sauna and have taken care of hydration so I'm not in the mood for googling.

[curtisa]

Acoustic responses for all five timbers, also as requested by @Bizman62. Just one file this time with a single strike of a D string for each species. The second part of the file contains the acoustic tap response of each timber.

Each plank was strung with a single D 0.026" string and mounted the same way as previously detailed, but without the pickup being fitted. A Rode M3 condensor mike was positioned vertically above the centre of the plank pointing down towards the pickup recess at a distance of 3". Recording was captured using the Presonus FP10 interface direct to disk at 44.1kHz 24bit. Note that the robo-picker has changed a little since the earlier photos were posted. I decided to remove the side-clamping action in case it was damping any internal resonances of the timber under test that may skew the results. The new mounting is free-standing from the plank under test. All recordings obtained thus far have actually used this newer variant of the robo-picker:

For the tap responses, the same recording setup was used and each plank suspended vertically in front of the mike, again positioned 3" away from the back of the pickup cavity. The timber was gripped between thumb and middle finger at the same point for all 5 examples, 140mm from the top of the plank, pinching the plank at the edges to allow it to sound as clearly as possible. A single knock from my calibrated knuckles  was used to get the timber ringing. Totally un-scientific, I know. But what you hear is the sound the timber naturally makes in the room when struck:

Running order inside the file is:

1. D-string pluck, tas oak
2. D-string pluck, blackwood
3. D-string pluck, celery top pine
4. D-string pluck, radiata pine
5. D-string pluck, kauri pine
6. Tap response, tas oak
7. Tap response, blackwood
8. Tap response, celery top pine
9. Tap response, radiata pine
10. Tap response, kauri pine

For convenience this matches the running order shown in the sustain table in my earlier post. Unfortunately there is more room and preamp noise in these recordings than the plugged-in ones. This is unavoidable given the extremely quiet sounds we're dealing with this time around. Regardless, headphones are highly recommended over speakers to listen to these unplugged string sounds.

I'd also highly recommend downloading a copy of an audio editor such as Audacity so you can cut and shuffle these recordings around as you please to make your own listening comparison sets.

FWIW, these recordings highlight the differences in the timbers quite clearly, although how that relates (if at all) to the plugged in sound is anyone's guess.

08 Acoustic responses.wav

[Bizman62]

Do you have a sustain table for the acoustic sounds as well? Or am I starting to ask too much?

One thing that was very noticeable in the sound clip was the pitch of the tapped woods. I wonder how much of a difference would it make if the boards were tuned to the same pitch... Then again, the Tas Oak and Celery Top Pine were within a semitone, yet there's a big difference in the low E and D electric sustains.

Re tuning the boards, a very quick an dirty test revealed that the spot where the board is held by doesn't affect the pitch, only the sustain.

[curtisa]

14 minutes ago, Bizman62 said:

Do you have a sustain table for the acoustic sounds as well?

Probably not very practical. The noise floor is so much higher in these recordings the sound has less 'distance' to go before getting buried in the background. You wouldn't get any meaningful data from it. Even if you could replicate the plugged-in recording characteristics I can't imagine you'd see anything different in the sustain readings. The string is still vibrating in the same way, the only difference is the way it's being captured - mike vs pickup.

 

20 minutes ago, Bizman62 said:

Re tuning the boards, a very quick an dirty test revealed that the spot where the board is held by doesn't affect the pitch, only the sustain

That's to be expected. The pitch will be governed by the mass and dimensions of the material. What you might find is that changing the 'pinch point' while holding the plank may excite or dull certain harmonic overtones in the struck sound, much like playing open string harmonics at various different frets. Again I'm not sure if that bears any relevance to the plugged-in sound or not.

A couple of things I would add to the 'struck sound' melting pot of ideas regarding different materials. The amount of force I apply to get the wood to elicit a tone is enough to knock it over. The same can't be said about the amount of energy in vibrating strings going back the other way, so it's not necessarily a valid comparison to say that the acoustic sound of a plank being tapped will immediately translate to an equal amount of tonal colour to the strings output.

The other thing that strikes me (hyuck!) is that when you play and hold a guitar is you cannot help but apply pressure with your hands, limbs and body at various points all over the instrument, which would potentially mute some (most? all?) vibrational resonances in the body and neck. A guitar that apparently rings well when suspended on a wall hanger and tapped probably won't resonate anywhere near as much when in the playing position.