Floating necks

Larry Clark · Post by **Larry Clark** » 15 Jul 2002 9:08 am

I've heard this term referring to the mounting of the neck so that it doesn't make physical contact with either the nut or the changer(at least that's my understanding). It would seem that the added mass of the neck making solid contact would increase the sustain of the guitar. Is this standard building procedure for most or all brands and if so,why? Just curious. Larry

Michael Johnstone · Post by **Michael Johnstone** » 15 Jul 2002 10:00 am

That sounds like a bad idea.The best sounding steels are designed to resonate as a total unit and have all the parts bolted,welded,screwed or otherwise bonded tightly together. The same goes for pickups.My 1980 MSA really came alive after I wised up and replaced the pickup mounting springs w/solid spacers. -MJ-

Gil Berry · Post by **Gil Berry** » 15 Jul 2002 3:49 pm

The reason for "floating necks" is so that downward pedal pressure is not transferred to the support of the neck - thus not contributing to "pedal drop". In addition - please do not equate mass with sustain. In fact, they are not particularly related. If they were intricately related, the Les Paul standard would sustain much longer than a Martin flat top - and we know that's not the case. In fact, the extra mass from all the undercarriage and changer apparatus on a pedal steel seems to DAMPEN the sound, rather than sustain it. Does ANY PSG out there sustain half as well as an old stringmaster?

Jody Carver · Post by **Jody Carver** » 15 Jul 2002 5:27 pm

Gil
Does any PSG sustain as well as a Stringmaster?? NO...NO Way.

Donny Hinson · Post by **Donny Hinson** » 15 Jul 2002 6:19 pm

I think the idea of "floating" the neck away from the changer and nut came about because of the use of aluminum for the necks. The aluminum would expand much more and much faster than the wood body, and this caused a lot of detuning when the temperature changed. Emmons began isolating the necks to reduce this problem. With wooden necks, I don't think it makes much difference. Also, added mass only adds to sustain up to a certain point...beyond that, it lowers the sustain by reducing sympathetic vibration. Along with the mass of the guitar, the size, shape, type, and hardness of the body material also have profound effect on the sustaining qualities. On some steels, a single neck style sounds better than a double neck.

Next time you see a violin player, ask them to demonstrate the way that the mute changes the sound of the instrument. It's really astonishing how much difference that small amount of mass can make on an instrument's sound!

Gil Berry · Post by **Gil Berry** » 15 Jul 2002 7:40 pm

Anyway, I think the main thing to enhance sustain is to isolate everything possible from the strings. You were partly right earlier when you talked about trying to get everything together as "one solid piece". Makes sense. Everything (and I do mean everything!) has a sympathetic frequency - and will react to that frequency and its harmonics - more than other non-related frequencies. Seems logical, then, that having FEWER individual parts (each with their own sympathetic frequency) would make the guitar less prone to be reactive to certain frequencies (read this as fewer "dead" spots) and thus sustain better. The best way, though, is to have NOTHING dampening the string vibration - changer, nut, pedal rods, pedals, etc. etc., and this can best be done (with current PSG's) by isolating the fretboard from as much of the guitar as possible. You were also right about the temperature expansion being so different with wood & aluminum necks - My Baggett (with an aluminum neck) changes about a MILE or so when the temperature changes significantly while my old MSA D12 classic, with wood necks, seems never to need re-tuning, no matter how severe the temperature changes. Wonder if that new MSA with the carbon filament construction is as immune to temperature changes as it's reported to be - and also how well it sustains. Anybody know? There should be a scientific test to give sustain time so an A-B comparison, rather than an opinion, is possible....

ed packard · Post by **ed packard** » 16 Jul 2002 6:49 am

Aluminum linear expansion for a given temperature change in the range of interest here is twice that of the the steel strings, and about six to eight times that of hardwood (grain in the direction of the neck). The surface to volume ratio and the coefficient of thermal conductivity for the particular materials of the body, neck, strings, changer, and tuning mechanism determine how long it takes for a change in temperature to become equal (nearly) throughout the instruments parts. Color plays a part in this in the direct sunlight.

If the materials other than the strings do not expand (have a coefficient of linear thermal expansion approaching zero) the instrument will change tuning with change in temperature.

The sustain issue is easy to test, ..using a VU meter (your tape machine or ?), an oscilloscope, or a spectrum analyzer, just time how long it takes the amplitude of the plucked string(s) to decrease to 1/2 of its original (after initial plucking) value (6db down point re voltage out).

There is available software for the oscilloscope and spectrum analyzer available for free on the net, ..just do a search for oscilloscope or spectrum analyzer software. This software converts your PC to the named instruments. Using the spectrum analyzer function, you may begin understanding "tone" because it shows the amount of each harmonic present in the signal as a function of where, how, and with what the string is plucked. The location of the pickup with respect to the string length (as played) will affect the harmonic content (tone) as delivered to tha amplifier. Electrical loading of the pickup may also affect the harmonic content of the signal from the pickup as well as the absolute output voltage, ..all pickups are not the same, and all volume pedals and or amplifiers do not present the same load to the pickup.

These same principles apply to the coupling of the strings to the changer/tuning mechanism/neck/body in that order. Aluminum nuts/changer radii will provide a different tone than steel of the same dimensions; want to hear the difference the material makes, ..use a wood dowel, an aluminum rod, or a glass rod as a bar. View these using the spectrum analyzer software to get a visual presentation of the results.