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I've encountered a few stores peddling sustainer clamps, and am absolutely blown away by the idea that they could do anything at all.

Metal sustainer clamp on a bass guitar

Can a solid metal clamp on the headstock of a guitar or bass guitar really add sustain to the notes? [How] Do they work?

Todd Wilcox
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1 Answers1

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The idea is that you are adding mass to the headstock, which increases the mechanical impedance at the nut, which reduces the rate of energy transfer from the string to the headstock, which increases the energy reflected back down the string.

If the mechanical impedance at the nut is already high (as it ideally would be), then adding a bit to the impedance won't make as big a difference, so this may be something that has a bigger effect on cheaper and/or lighter guitars and basses.

Also, I don't quite understand if and how this has as similar effect on fretted notes as it logically would on open notes, aside from adding mass to the neck overall. I would expect that the higher you play on the fretboard, the less benefit there is to a device like this.

Online reviews and reports seem to indicate a modest but noticeable effect, and bass players seem to report that they help eliminate "dead spots" on the neck, meaning frets and strings where the notes don't sustain as long as the rest of the notes.

The mechanism for eliminating dead spots seems to be that the weight of the clamp changes the resonant frequencies of the neck itself. A resonant frequency of the neck would also be a point where the mechanical impedance at the nut is relatively low, so shifting a resonant frequency to a frequency where the instrument is not played would again preserve a higher mechanical impedance.

Whether you should buy one is probably not an easy question to answer. They're not very expensive, so it could be worth a shot, but then you have the possible issue of yet another mathom in your musical junk drawer. It also seems like the better your guitar or bass is right now, the less you have to gain from a device like this, but if you have a cheap but decent instrument this might kick it up a notch. Finally, since it adds weight, it can also add discomfort and encourage neck dive. If I were considering one I'd try to see if I can try one out at a store, either on my actual guitar or on a reasonably identical model at the store.

Todd Wilcox
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  • Well answered. I would lean more towards the 'mathom' description, myself, but I'm kind of a minimalist. – Thomas N Jun 02 '17 at 21:47
  • Excellent answer. I agree that the effect is likely to be marginal on most instruments but could be useful for cheaper ones. I've never used one myself, but it's perhaps worth noting that the positioning should make a difference to the performance too, and that it's not just about adding mass to the headstock. Adding mass to a node/antinode of a headstock eigenmode is likely have less/more of an effect than just a random position. This will have a frequency dependence, so expanding the base of the clamp (where it is in contact with the headstock) could be a good mod. –  Jun 03 '17 at 23:16
  • "The mechanism for eliminating dead spots seems to be that the weight of the clamp changes the resonant frequencies of the neck itself." Wouldn't it create new one(s)? – Eric O Jun 06 '17 at 19:47
  • @EricO Probably. So if it actually works it probably works by creating new resonant frequencies that are outside of the range of fundamental frequencies of the notes on the guitar neck. Really a better way to think of it might not be that it removes some resonances and creates others, but that it shifts the resonant frequencies down far enough that they are too low to have an impact. – Todd Wilcox Jun 06 '17 at 20:53