Octave mandolins: archtop guitar shape vs mandolin shape?

[Kroland]

I've been listening to clips of octave mandolins, and keep running across Fletcher Brock's archtop guitar-shaped OMs. They sound incredible. The only OMs I've played have been more of the standard mandolin shape. Does anybody know what the tonal differences might be between a guitar-shaped OM vs mandolin-shaped OM (assuming they're both archtop, f-hole, same scale length, etc.)?

[belbein]

Pull up some clips of Sara Jarosz, playing a big old GBOM. To me it sounds much more full and bass-y than the MBOM. But I have to admit that I also just love the look.

[Kroland]

Yeah, she's the main GBOM I've been watching (and loving it!). That Fletcher Brock makes a beautiful instrument!

[foldedpath]

Pull up some clips of Sara Jarosz, playing a big old GBOM. To me it sounds much more full and bass-y than the MBOM. But I have to admit that I also just love the look.

A counterpoint from the mandolin-body OM side (at least for modern, younger performers), is what Sierra Hull does with a Weber Yellowstone OM.

Two examples here... the first a bit of a promo for Weber but still interesting, the second in a Bluegrass context:

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Disclaimer: I have never held or played a guitar-bodied OM (GBOM), so take the following with a grain of salt:

I have always been drawn to the more "focused" mid-range sound of the traditional mandolin-derived instrument. If you can call something this big a smaller body!

I play a Weber Yellowstone F-style OM, and I just love that sound. It sounds like a big mandolin, and not something close to a 12-string guitar in 5ths tuning. To my ears, the GBOMs I've heard on YouTube etc. tend to approach that sonic neighborhood. I want a big mandolin, not anything that could be remotely confused with a guitar.

That said, I can understand why some folks are drawn to the GBOM version. With a bit more bottom in the bass range, that's probably an advantage for singer-songwriters performing with it as a main instrument. If you're performing in a band though, or even with a guitar player, there are other instruments getting deeper into the bass range. It can be an advantage to have more string energy going into the mid-range, so it can be heard among the other instruments.

[Kroland]

What a great response! Thank you for your insight; it rings true with what I understand about the differing body types. And that second Hull video is new to me, and I really like it!

I've actually been considering commisioning a guitar-bodied mandola, and I thought I'd start with OM comparisons before hunting for a possible builder.

[trevor]

I've had many GBOMs in from Bill Bussmann (Old Wave) and Austin Clark and I agree with belbein 'it sounds much more full and bass-y than the MBOM.'

[belbein]

a guitar-bodied mandola. Have you looked at Weber's Octar? It's not a mandola, but it does look like a beast.

[Kroland]

Wow, in the few youtube videos I've found I'm hearing a notable difference in timbre between the Old Wave, Weber, and Brock GBOMs. But Hull's MBOM is clearly a different animal.