I finished my first build, mostly, and I’m very happy with the results.
Here is a question: I don’t have a sound hole yet. I am very happy with the sound of the piezo that is wedged between the neck and the lid. I like the sustain I am getting through the amp. If I drill a sound hole or two, and if it is louder, when played acoustically, will that reduce my sustain through the amp? If I am happy with the amplified sound, should I just leave it alone?
So far in all my builds I haven't been disappointed with the sustain of an electric with a sound hole. The hole will give you more acoustic volume though.
I think your sustain is more about your setup. If you have a good sustain now, a well placed sound hole shouldn't affect it.
Thanks for the input. My logic for the question is that if a guitar is louder, acoustically, the energy needs to come from some place, so it logically needs to come from the string vibrations. Using the same logic helps explain why the solid-body electric guitar has better sustain. I know that Helmholtz resonators can be used to absorb sound energy (bass traps, etc.).
I might be over-thinking it. Of course, I could always experiment and build another guitar.
I guess a lot of the sustain is in frictional loss at the bridge and nut. I experimented with putting my bridge (threaded bolt) on top of a piece of wood, to raise the strings, but that definitely reduced the sustain and made the strings a bit dead...I used a scrap of poplar I had sitting around, which is apparently too soft for this.
You could try making the sound hole(s) in the side of the box opposed to the top. That way it won't change the vibrations of the top (where the piezo is mounted).
Sounds like something worth trying. I guess, technically, any air resonance will involve the lid to some degree, but certainly not cutting a hole in the lid will make some kind of difference in how it vibrates.
As we know sustain is the audible duration of a note. We know that the vibrating string creates the soundwaves that are amplified by either a pickup or a soundboard/top/sound chamber, the longer that string vibrates with enough energy to drive the top or pickup, the longer the note will sustain.
As already noted above solid bodied guitars have longer sustaining notes, This due to the slower loss of string energy/vibration due to the solid body timber and more solid string mounting points.
In the acoustic guitar I see the same thing happening, a guitar with a thicker more solid top will have good/longer sustain, but possibly less volume, especially without a soundhole. Now if one puts a soundhole in that top it become a bit more flexible, so taking more energy from the strings so the vibrations decay quicker.....shorter sustain.
That's the challenge one faces building acoustic guitars, to tune the top braces in the top to give the best of 3 worlds, I suppose, structural stability, flexibility, and stiffness. I see that as Durability, Sound Ability, and Sustainability....I just made that up.
Any way, In the photo you can see an electric CBG that had no soundhole, but as I wanted to hear it unplugged, as suggested above, I put a soundhole in the side. You can see that it had a soundhole grill over the hole you would be surprised how much louder the sound is when the grill is removed.
Sorry to ramble on
Common window screen will cut air movement by ~50%.
"Sustain" comes from how rigid the nut-to-bridge structure is. As the string moves does it flex and absorb energy or stay rigid and reflect the energy back into the string. micro-amouts make a difference. If you pull outward on the string, how much micro-bowing does the neck exhibit?
think of a porch-post type diddley bow made out of a piece of pipe with bolts for the nut and bridge. Black Steel Natural Gas pipe will have a lot more sustain than PVC.
Hi JL, your use of two different pipes to illustrate how the density of the material used can effect sustain is a good one. But I would add another material to the group that may give another perspective......A cardboard tube of a similar diameter
This is how I would expect the results to look regarding sustain duration, note quality and volume. The audible duration of a note/tone. Using the same gauge string on each of course.
Steel pipe...very long string vibration but little in the way of audible tone sustain -
PVC pipe ....shorter string vibration but longer audible tone sustain -
Cardboard tube....short vibrating string duration shorter less audible tone sustain.
Sustain is not the be all and end all for all guitars and musicians, as builders we have to find a balance between Volume, great tone and sustain, in my view.
Hmmm...it seems to be a matter of trade-offs...you have to decide what sound you want, what kind of music you are playing, whether you are using an amp, what kind of pickup you are using (if any), whether playing at home or on stage, etc. My old Epiphone lap steel has great sustain, but it is a totally different instrument with a totally different sound.
Yep hi Michael, I would not stress over it too much, just build with what you have at hand. Enjoy the building and enjoy playing it. Don't get too far away from the true sound and traditions of CBG's.
Short story....I had and old parlour style guitar hanging in my motorcycle shed, and one day I tuned it up to play. It was so old and out of shape I had my eyes closed in case it flew apart. But the sound from that guitar was pure delta blues, old strings, no sustain, and the bass was more of a thud than anything. I loved it for that type of blues.
So.....I went ahead and built one like it, but I could not get that sound out of a crispy clean sustaining sound that, that guitar had. It did not get the juices running at all. It found a happy owner though.