Acoustic comparison - Carved vs lam, full depth vs thin, floater vs set

[nevershouldhavesoldit]

A current thread on an Eastman 175 clone has raised a lot of discussion about the acoustic sound and feel of archtops of various types. So I thought I'd try a little comparison to see if I could produce any useful information. I think I've succeeded and look forward to learning how others feel about it and if this has helped anybody. Chris32895 (the OP) thought that an Eastman 175CE (which is apparently the same as the 371 that we get here in the US) would be " ...a resonant 175 style guitar that would be nice for fingerstyle and pick playing". I suspect that he assumed the top was thinner than that on a 175 because Eastman carved tops are made in the Benedetto style and are thinner than those of the classic Gibson carved archtops of the '60s and later. But I don't know of any factual reason to think this and suspect that the top on his Eastman 175CE is probably close to the same thickness as that on any standard production 175 made since the 1960s. I can't verify this because I don't have access to either guitar. But for whatever reason, he clearly was not expecting the acoustic tone and playing feel that he got, summing it up like this:

"What I wanted was a resonant 175 style guitar that would be nice for fingerstyle and pick playing. What I got was a much thunkier guitar with probably the best electric sound I've gotten from an archtop yet, but really almost no acoustic presence."

The OP and the thread go on to raise a few basic questions that we talk about all the time. There are several YT videos test driving the 175CE / 371, including a good one by Rich Severson. But I've not yet seen an attempt to demonstrate and shed light on the basic questions raised by this discussion. How do the acoustic tone and volume of archtops that are identical except for having a carved or laminated top compare? Can an archtop with a laminated top possibly produce great acoustic tone, volume, projection, and playing feel? How does a set pickup with parallel bracing affect acoustic tone and volume compared to a floater in a cross braced top? The other question we see raised all the time but never addessed directly is whether an archtop with a thinner body can produce the same richness and volume of acoustic sound that a full depth can deliver.

I don't have identical guitars with different tops, but I do have very similar guitars whose biggest difference is that one has a carved top and the other has a laminated top. And I have a full depth 17" carved archtop with X bracing and a floater to compare acoustically to a 16" thin (2 1/2") archtop with parallel bracing and a set HB. So I set out to answer the following:

1. What are the differences in acoustic volume and tone between a thin topped, X braced, full depth 17" with a floater and a slightly thicker topped, parallel braced, 2 1/2" deep 16" with a set humbucker (both built in the same shop to the same standards)?
2. How do the acoustic volume and tone of an archtop with a carved parallel braced top with a set HB compare with the acoustic volume and tone of an identically sized laminated archtop with parallel braces and set HB?
3. Can a laminated archtop sound as good as a similar guitar with a carved top?

I recorded the last 16 bars of Just in Time played acoustically on 3 of my archtops without changing my position, mic position (crossed steeo mics about 6" away from and centered on the strings at the end of the fingerboard), or any settings. The guitars are an Eastman 810CE7, an Eastman Jazz Elite, and an Ibanez AF207. The Eastmans are both solid wood with carved spruce tops and maple bodies, while the Ibanez is a laminated maple box. The 810 is a full depth (17" x ~3.25") archtop with a thin top, X bracing, and a floater. The 16"x2.6" Jazz Elite has a thicker carved top, parallel bracing, and a set HB. The 16" x ~2.65" AF207 is a parallel braced, laminated box with a set HB and clear plastic pickguard material covering the F holes to reduce feedback (a very effective approach with essentially no visible impact). The Eastmans have TI JS113s plus a 75 thou Chrome 7th, and the Ibanez has TI GB114s with the same 75 thou 7th Chrome. All were picked with a Dunlop Jazztone 204 at the end of the fingerboard, and I tried to keep all 3 takes as consistent as possible.

The first 3 tracks are the raw sounds of each guitar. I tried to take them through a wide dynamic range, with some big chords and some single string runs. So the relative volumes are what you would hear live. Interestingly enough, the differences in volume were not nearly as apparent while playing as they are when listening to the recordings. None of these guitrs was plugged in - this is all acoustic tone captured by a crossed pair of cardioid mics close to the strings. Here are the 3 raw tracks:

810:


Jazz Elite:


AF207:


The currently active thread about the Eastman 175CE also raises the question of the relative contributions of volume and tone to overall acoustic sound. To look at this a bit more, I brought the average volume of these 3 as close to each other as I could with a little compression followed by peak normalization to -1 dB. Here are the three tracks from above, now at approximately the same volume level. I think volume is only a minor contributor to tone in the range that encompasses carved vs laminated archtops of about the same size. Our auditory systems are less sensitive to low and high frequencies at lower volumes compared to the middle range, so louder does sound bigger and fuller in general because we hear the very lows and the very highs better and better compared to mids as the volume comes up. But the difference in SPL between a carved top 16" and a laminated top 16" is not really big enough to make a major difference in this regard.

Here ae the above tracks at approximately equal volumes:

810:


Elite:


AF207:


I love all three of these guitars. The big one (810) is a little louder and a good bit warmer to my ears than the smaller carved one (Elite). The basic tone of both is similar, but the bigger body seems to deliver a bigger sound. The set HB and parallel bracing probably contribute to the relative prominence of the mids and lower mids in the Elite. The Elite and the AF207 are almost identical in size and basic design, and their basic tonal characters are actually not too far apart. But there's no comparison at all in acoustic volume and projection. I don't think the covered F holes are a big factor in acoustic tone, since I notice no difference with or without them. One of these days, I'll pull them off for a recorded comparison to see if this is accurate. But for overall acoustic tone, the carved Elite is louder, warmer, and richer than the laminated AF. The tonal quality of the AF is pleasing to me, but it's a sterile sound compared to the carved ones.

As a postscript, I have to add that I've played laminated achtops that sound excellent acoustically. Dale Unger's laminated American Archtops sound wonderful and are far more pleasant to my ears and hands than many highly touted carved archtops. HIs Amrican Deam is a fantastic guitar that I'd take over many fancier and more expensive substitutes because it just sounds and feels right. The Moll Pizzarellis are great in this regard. Laminated tops can be wonderful acoustically, and it's pure snobbery to categorically dismiss them because they're ply.

[Spook410]

That was a bit of effort and took some skill recording and playing. Thanks for doing this. The sounds are very instructive for those that listen closely.

I also like that these are accessible guitars. Not expensive boutique models or rare antiques.

[John A.]

Listening on a decent JBL bluetooth speaker, the volume differences weren’t all that dramatic. I suspect close mic’ing tends to minimize that difference. But I found the differences in timbre to be quite striking. The 810 is a world apart from the others.

[Cunamara]

Thank you so much for doing this! It is an interesting demonstration. As a matter of taste, I actually preferred the sound of the Jazz Elite over the 810. It was clearer and better balanced, preserving note separation whereas in the 810 things got jumbled together and rather muddy. Bigger is not necessarily better in archtop guitars (nor in flattop guitars, for that matter).

There is a video of Steve Andersen making a double top archtop, a three ply laminate with two outer layers of wood and an inner layer of Nomex synthetic material. Bill Frisell plays it at one point and talks about it. It's always hard to judge the sound of a guitar in a video on YouTube for many factors, but his comments about the experience in person are that it's a very lively guitar with a lot of complexity in the tone- the opposite of what we usually think about and laminate guitars.This is a very different design than a typical laminate instrument, but it provides another point of information.

[grahambop]

I recently recorded my Gibson 175 acoustically (I was messing around with my Rode NT4 stereo mic and wondered how it would record the 175). The guitar was strung with .012 Chromes and I put the mic a few inches away from the lower f-hole.

(My 175 was probably made in 1976, going by the serial no.)

Anyway I thought it might be of interest.

[Cunamara]

Any doubts left about how "Virtuoso" was recorded? ES-175, a mic, no amp. Or at least not an amp that was working or recorded.

[nevershouldhavesoldit]

Listening on a decent JBL bluetooth speaker, the volume differences weren’t all that dramatic. I suspect close mic’ing tends to minimize that difference. But I found the differences in timbre to be quite striking. The 810 is a world apart from the others.

Distance from mic to source definitely affects the sound quality. Most cardioid mics pick up voices and acoustic instruments best at about 6 inches, which is why I used that distance for these recordings. Any closer than that produces a bass boost ("proximity effect") that can muddy the sound. But volume is volume regardless of mic location. It drops off at 6 dB for every doubling of distance from a point source, which is defined as a source that's much smaller than the wavelength of the frequency. In real life, a guitar is mostly a point source for very low notes - the wavelength of a low E (82 Hz) is about 12 feet and the main sound radiating surface of the guitar is about a foot across. The wavelength of a 1000 Hz tone is about a foot, and as frequency goes above that it drops off precipitously. This is important because SPL drops progressively below 6 dB per doubling of distance as frequency goes up because of phase effects and the increase in proportion of ambient reflections further from the source.

The proximity effect can make a bass heavy signal significantly louder through a mic placed too close to the source. The 810 has more bass in its tone than the Elite or the AF. So even if the overall SPL of the two guitars was the same, proximity effect would make the 810 artificially louder in a recording than the other one because the boost is frequency dependent. A true 3 dB average difference at our ears may be recorded as a greater one if the mic is too close and one guitar has more bass in its tone than the other.

I would have recorded these with mics 3 feet in front, but the air conditioning is audible enough with close mic'ing that it would have been a real distraction. It was over 90 degrees today and humid, so I didn't want to turn off the A/C for an hour to keep both me and the guitars comfortable and in a stable climate. If I had a silent studio, a pair of crossed cardioids a few feet from the guitar would have gotten better sounding recordings. But I'm confident that the 6" distance beteen strings and mic was enough to eliminate proximity effect. What you hear is what I got.

I also ran a spectral analysis on each track. The graphs are interesting. Notice that the peak energy in all 3 tracks is at about 250 Hz, which makes sense since the program material is basically identical and all the energy in that range is fundamental tones and low order harmonics. That peak is highest for the 810 (-14 dB) and gets progressively lower for the Elite (-17 dB) and the AF207 (-18 dB). So the 810's peak SPL is about 3 dB louder on average than the other two, which is a small but audible difference. Then look at the graph between 70 and 200 Hz. The Elite is about 6 dB quieter than the 810 and 10 to 12 dB quieter than the AF.

Now look at the content at and above 3 kHz, which is essentially all harmonics - there are no fundamental tones that high coming from a guitar. E1 is 330 Hz, so the 24th fret on E1 is 1320 Hz. The 3 kHz + range is an average of 3 to 6 dB higher for the AF207 than it is for either of the others. Between 7 kHz and 10 kHz, it's still 3 dB or so higher. This is why it sounds so much thinner and brighter. Spectal analysis clearly shows that the laminatd top is louder than the carved tops above 1 kHz but is much brighter and has less low bass.

810 spectrum:


Elite spectrum:


AF207 spectrum:

[nevershouldhavesoldit]

I recently recorded my Gibson 175 acoustically (I was messing around with my Rode NT4 stereo mic and wondered how it would record the 175). The guitar was strung with .012 Chromes and I put the mic a few inches away from the lower f-hole.

(My 175 was probably made in 1976, going by the serial no.)

Anyway I thought it might be of interest.

Fascinating! It sounds like a 175. I'm amazed at the similarity of timbre between your 175 and my AF207. It's especially close to the normalized AF track in sound quality This is the typical acoustic sound of the genre - a high quality guitar with laminated maple top on maple body with set humbuckers in a parallel braced top. You and yours both sound great, BTW!

[grahambop]

Thanks! yes there seems to be a specific acoustic sound associated with this type of guitar.

Mine’s not particularly loud, that’s why I placed the mic fairly close.

[Freddels]

Dave Mooney plays a laminate Benedetto (Bravo Deluxe 7) and his guitar sounds great. Very clear and articulate.