Soundports?

[nnickusa]

Due to hearing issues from many years of working with power tools before ear protection was considered "manly," I have trouble hearing acoustic guitars when I play them. I'm not deaf by any means, but challenged in certain frequencies...

I'm not planning on doing anything at the moment, but maybe on the next one.

Question is, how does the creation of a soundport affect the overall sound quality and projection of an acoustic?

It seems to me with only my high school physics to go by, that introducing another avenue for the sound to escape the body chamber, it must have some effect on tonal and projection elements of the guitar....

Ideas?

Thanks,
Nick

[Nick]

You've poked a bit of a hornet's nest here Nick There are two very different camps of thinking on soundports with one camp saying they improve the sound of a guitar and the other camp that say it's all snake oil & will effect output. The physics of it says that it must alter the resonant frequencies of the box but is it to it's detriment or to it's benefit?
Al Carruth wrote a good paper on soundports (http://www.alcarruthluthier.com/Downloads/sidePorts.pdf) using his now famous "cork" guitar, it was called that because he basically drilled a number of 1" diameter holes over the side of a guitar then stuck corks in the holes which enabled him to remove a particular cork & test it's effect in any position on the guitar's side using measuring instrumentation in order to get quantifiable results. Trevor probably has some good scientific arguments to put forward on this also
Personally I've built one guitar with a side or soundport & the customer liked the fact that he could clearly hear the guitar,as compared to how he usually heard a guitar, whilst playing it. Standing out the front, I couldn't hear any real discernable differences from the non ported one except maybe a slight increase in bass frequencies coming out (it had a slightly 'richer' sound), but whether I was imagining this I can't be certain as it could have just been any number of other factors (Body shape, top bracing, type of timbers used and also it was the first guitar using my double back idea. e.t.c)

[kiwigeo]

The only useful ports are the ones that come in bottles

[seeaxe]

Warning - somewhat frivolous post - sense of humour deployed, (or at least attempted)

As I can now claim vast experience on guitars with soundports (2) I feel well qualified to respond to this post.

Based on no scientific analysis whatsoever, but on lots of playing them, I can categorically state that I personally can't tell the difference between guitars with or without soundports. From this I conclude that

a) its another one of those factors like type of wood, arrangement of bracing etc etc that can all make some difference but its hard to know what that is with all the other things that are different even between two supposedly "identical" guitars
b) It doesnt make the sound any worse either
c) Its handy when you drop your pick/sandwich/carkeys inside
d) Its cool to be able to look inside and show off your joinery skills to other people (as long as they are not luthiers, as they are anal and will point out all the mistakes.......)

Seriously, if you have a hearing issue, I doubt a soundport will make any differnce, but they are fun so why not? You can always glue a patch on it it you dont like it.

Good luck

PS.... maybe its an idea for our industrial designer from Adelaide to investigate

[nnickusa]

As I mentioned, I'm not deaf--other than tone deaf --but seriously. I have noticed that I can hear my Ovation better than other tradionally built acoustics...

Would a sound port, picks, keys and sandwiches aside.....project sound towards ME and increase the sound waves that come to me----seems the waist would be the place for that----never seen one on the waist----without having a detrimental effect on the sound projecting out the front?

Looks like me or Adelaide might have to try one out to see

Yikes. there's alot more to this stuff than just sticking a bunch of wood together so it looks good....might be time for a

Thanks,
Nick

[Allen]

I've built a couple guitars with them, and a couple of ukes with them.

In all honesty I couldn't tell if there was any discernible difference at all in them. Sure to start off with I felt that there was, but after building quite a few more instruments I think that it was more to do with both thinking that there had to be a difference, and that I was building an instrument that had better "enveloping sound" as opposed to one that throughs it to the back of the room. And all that I've read from credible sources say about the same thing. Blind listening tests an all.

If what you are looking for is a guitar that you enjoy listening to in a small room, then I'd suggest that you look at building with that in mind. And I'd be looking at a parlour guitar in that case. I love the style 5, and I've heard a couple of Bob's 00's. Much different that a larger bodied guitar.

Ervin Somogyi talks some on this in his videos and books about different ways of bracing to bring out aspects of the instrument that you are looking for. Perhaps Trevor and Gerard's book discusses this as well. I don't know since I don't have them.

[Kim]

I have found that a sound port the size of a large egg will not hold a stubbie. But it does seem to lift audibility of the trebles, particularly for the player...but then that makes sence to my way of thinking because when you add a port you've effectively increased the size of the soundhole which must decrease the helmholtz mode. I know sweet FA of the science but in general terms the helmholtz mode is related to pressure, and within reason, a smaller soundhole is desirable if you are trying to promote greater bass frequencies.

Cheers

Kim

[Trevor Gore]

There's nothing in "the book" about sound ports. As far as Gerard and I are concerned, we've yet to hear a guitar that sounds better out front for having one. All the ones we've heard have lacked projection compared to having the port sealed.

The player occasionally hears more with a port, but our view is that a well designed guitar should give a good representation of itself to the player as well as the audience, and you don't need a sound port to achieve that. It's not that we're against the concept; it's just that we haven't heard one that works well enough for us to bother pursuing the topic, either practically or theoretically.

However, as Nick suggested, there may be a lad in Adelaide looking for something to do...

[Craig]

I made a matching plug for a soundport I included on this 12 string . Consequently I can easily play with or without the port. I think "size does matter" in this case. You don't want it too big ! I made the soundhole a bit smaller to allow for the soundport opening
There is a marked difference . I've asked many listeners which they prefer and in almost every case they have prefered the sound with the stopper removed. Most claim it to sound louder but I have no scientific proof . It could be that the extra higher frequencies emitted with the port working may make the guitar seem louder to the human ear.
When playing it , I much prefer to have the port open . It gives me a good report much like a monitor. . The stopper tends to live in the case ,,, unused .
I mainly included a port on this guitar as it was built with thick sides and massive liners. The type of guitar that radiates sound mostly from the soundboard . Tends to throw the sound out front away from the player .
On the other hand, I didn't include a soundport on a (much lighter ) mahogany guitar I recently finished as it is the type that radiates sound from most of it's body ( a real chest thumper ! ) Great to play !
I don't believe a port is required or suited to those type of instruments.
Here's a pic of the 12 where you can see the port stopper.

lmis241.jpg (145.67 KiB) Viewed 10301 times

A soundport does NOT double as the ideal ashtray

[nnickusa]

WOW, Craig, that guitar is beautiful. Another one that makes me more reticent to put up photos when I finish my first OM. You guys are just too good.

The plug is a nice touch. Did you cut it out before bending? the grain looks perfectly matched?

As mentioned, others hear my guitars perfectly, but my soundport query is to see if I will hear it better...I just may try the port/plug route to see for myself.

Thanks for posting Craig....

[Allen]

That one isn't even big enough to hold a stubbie.

Interesting your observations Craig. In the ones I've built the sides and back I would call responsive, so perhaps that's the difference.

[Craig]

WOW, Craig, that guitar is beautiful.

The plug is a nice touch. Did you cut it out before bending? the grain looks perfectly matched?

Thanks Nick, No ,the soundport cut-out isn't big enough to make that stopper ( it's larger than the actual soundport hole as you can see.) I hunted through all the off cuts till I found a piece to match the grain perfectly. I also bent it to suit the upper bout . Went to all that trouble and now the plug tends to live in the case

Interesting your observations Craig. In the ones I've built the sides and back I would call responsive, so perhaps that's the difference.

Exactly the point I was trying to make Allen when mentioning I didn't include a port on a much lighter Mahogany guitar.
I'd have to conclude that I'm probably not exactly a soundport fanatic, although they can add to the player's enjoyment when playing a heavily built guitar .

[Nick]

WOW, Craig, that guitar is beautiful.

I still wanna lick the screen everytime I see it Nick and I've seen it a few times! Our Craig is certainly an artisan.