I was comparing my RG2570e that I just bought and my RG570 Swirltop last night and I noticed a very significant difference in sustain between the two. So I'm wondering what makes one guitar sustain so much more than another when their construction is so similar.

The RG2570E has the stock Dimarzio/IBZ pickups and an Edge Pro bridge while the RG570 has EVO's and an Original Edge bridge, although the RG570 had beautiful sustain with just the stock V7/V8 pickups as well.

When I was refinishing my RG570 and another guitar I used the neck, body, and bridge in a few other combinations so I would have a floating trem guitar to play, but none of those combos ever produced the same sustain. Even using another RG570 body with this 570 neck did not produce the same...

Is it simply some combination of neck and body that, when combined, just resonate magically together?

Frequencies will be absorbed or allowed to vibrate depending on the wood - both the neck and body. Opinions differ, but I'm confident that the main factor - given equal setup and "craftmanship" (quality in neck joints etc) - is the wood.

That's what I was thinking after all the swapping around of parts I've been doing lately.

I also forgot to mention that the neck pocket fit was always tight no matter the combo. I don't know about the RG2570e yet as I haven't had it apart, but it seems like a snug fit...

Pickups play a large part too, my guitar has 2 single coils and they do not sustain very well at all. the humbucker does!

Just check out this video ww*.youtube*com/watch?v=zmFSivO5Tuk from 2.46 until around 3.40. Vai said that the reason why he love his EVO -technically- is the freq of wood of EVO body and neck are same, this is very very rare and that's why EVO can 'sing' the notes very nice...

watch all vais videos and you will see he is full of crapp.
Hes a wanker ( he will even tell you he is).

Did you just post that on the Jemsite?

Good guitar player though.

Hahahahahahaha, that made my night haha!

Can't believe he got off with that one.

I always thought he was full of crap on that one too, until I got this RG570. I never though a floating trem bolt-on neck guitar could sustain as well as this one does. It may be something totally different, but maybe the neck and body match up just right, maybe it's just a good chunk of body wood, or maybe it's the neck, but something about it is different than all the other RG's Ive ever owned... I guess I should just feel lucky

I do have a little gap on one side in the neck pocket: the gap between the neck and the body is less than 1mm but still is there. I unfortunately don't have pictures showing the gap.
I know the sustain is quite weak, which is p****ng me off regularly.

I guess there is only one trick (as filling the gap with a small piece of wood will not improve the sustain drastically IMO): the sustain block.
I think about making my own sustain block, but I don't know what to choose as material: copper or brass...

I can tell you as a physics major that it has absolutely nothing to do with "resonance," or anything like that. In fact, resonance in the body or neck is the last thing you want if you want good sustain. The only energy available to the vibrating system comes from you picking the string, and as more energy is transferred from the string into the body (wasted energy), less is available to the string to continue its vibration.

I believe that sustain is a result of a balance between the magnetic pull of a pickup and a string's natural vibrations.

Well maybe it's more like the anti-resonant properties of the wood that absorb less of the vibrations of the strings and allow them to vibrate more efficiently and for a longer period of time resulting in more sustain...

Yes, I agree. In fact, civil engineers put a great deal of effort into minimizing this type of vibration in the structures they build. The dimensions of buildings, bridges, etc. have to be carefully chosen to reject such vibrations.