Sound Holes and Sound Ports

[Tom2]

As options multiply, and a/b comparisons are somewhere between difficult and impossible, does anyone here have the ability to make some comparison recordings, or share a description of personally comparing different configurations?

Clearly, since all of the energy in a note comes from plucking the string, any amount of that energy directed toward the player will be subtracted from the energy directed forward. The need or desire to hear one's own performance varies from person to person, is affected by ambient noise levels, number of players, audience size, room size, plugged in or unplugged, etc.

What I'm really interested in is how sound hole location, and the presence or absence of a sound port, affect the tone of the forward sound that would be picked up by a microphone, either for recording or live performance with a purely acoustic instrument.

The Rainsong CO-WS is available with center or offset sound hole, but the center model is a 14 fret long scale and the offset model is a 12 fret short scale. Tough to isolate the sonic contribution of sound hole location with such different configurations. The CH-WS is center hole, 12 fret, short scale, so a comparison between a CH-WS and a CO-WS1005NS may be more illuminating. No Rainsong sound ports.

The Blackbird Savoy is center hole only with an opt-out sound port. Maybe someone could record a Savoy with the port open and plugged.

Emerald has merged the sound hole and sound port into one, so there is nothing to compare.

The traditional center hole location probably has a good reason for being, maybe for louder forward projection back when there was no sound amplification, maybe for superior tone. Hard to say without comparisons.

[Carbonius]

I won't answer the guitar questions, as I've only played the standard Rainsong's. However, the addition of a port can actually INCREASE overall volume. You'd think not, but it's been tested. McKnight did some tests years back, I went and found the link. It's a longer read, but interesting.http://www.mcknightguitars.com/soundports.html

[kramster]

I be really liking the sound port on me Savoy I tell ya.When folks play it I let them play some and then cover the port with my hand and then move my hand. I think they either really like the sound open or really don't like my hand there so close to them... either way the open port is the sound of choice.... The Emerald X20 with the hole where it is works really well as well.

[Tom2]

Originally Posted by Carbonius

the addition of a port can actually INCREASE overall volume.

Certainly, and it can improve bass response, which is desirable in a small guitar, while also strengthening dispersion in all directions.

Magic? Nope. 100% still equals 100%, and these gains come at the expense of sustain. The additional port reduces internal air pressure, allowing the top to vibrate more freely, and the energy from the string to transmit into the top more quickly. Deeper bass, wider dispersion, and shorter duration.

As anyone with a home studio would know, many loudspeakers have sound ports, some rear firing, that improve bass response which can be heard from the front.

I think sound ports are a great idea, and point to a possible future where very small guitars have very impressive bass.

[Tom2]

Originally Posted by kramster

When folks play it I let them play some and then cover the port with my hand and then move my hand. I think they either really like the sound open or really don't like my hand there so close to them... either way the open port is the sound of choice....

As a legendary youtube master, could you do an a/b recording (of the guitar, not your hand), full frontal, acoustic only, single mic, with the port open and plugged?

Mr. K: and do it with one of your many models.