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#1
05-20-2012, 12:39 AM
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Planet Waves O port
Hmm. Reading another thread on here about the size of the soundhole, the Planet Waves O port is mentioned. I researched it on tinternet and found (amongst others) this video: http://www.planetwaves.com/PWVideo.P...t_Product_Demo
The difference it would appear to make is nothing short of dramatic - almost as though the video had been, well, faked or set up in some way. The volume and tonal differences are really obvious. Is that real? Any comments? Anyone used one? BTW, it goes without saying, your computer is best hooked up to a full range speaker system in order to get the full effect of the bass etc. An inbuilt or tiny external computer speaker will not do (any) audio comparison justice.
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars.. 
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#2
05-20-2012, 01:26 AM
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Just as I thought. I have now watched some more demos on Youtube and in fact, the opposite effect seems to be more the case, ie the bass seems to be reduced using the O port. Also the upper mids are enhanced. Yes the sound is somehow 'smoother', but the overall effect is to make the guitar sound like a half decent cheap electro-acoustic. High end guitars built with good wood can have a slight tendency to sound boomy, I for one find it an endearing quality in small amounts. This device just seems take the soul out of the guitar and turn it into a generic acoustic guitar recording sound.
I'm convinced that there is something going on untowards in that first video. Every other video seems to show a bass droop, that one shows a dramatic boost and an overall improved sound. It's one on its own though - that's the problem..
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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#3
05-20-2012, 04:20 AM
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There does seem to be an increase in clarity and bass projection... but I wonder if this is due to the woods in the guitar?
Has one guitar aged and opened up its sound characteristics? Any one used this product?
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#4
05-20-2012, 05:23 AM
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Quote:
http://www.youtube.com/watch?v=q28iNciVLus Also, I simply do not accept any such comparison when two guitars are used (as in my initial post), as no two guitars are the same, and given that we could be looking for subtle differences, such differences may already exist between the two guitars. It's a none starter. Here's another comparison where the guitar pitch is different for each test! And these guys are supposedly producers! unbelievable.. http://www.youtube.com/watch?v=ZtfSE...eature=related There does not appear to be an obviously fair test (in video form) on tinternet, they are all flawed in some way. Beats me that these people cannot just take a single guitar (with new or slightly used strings - it does not matter), play it without the O port, then install the O port, change nothing; mic position, playing style, hardness etc, and record it. The first video in this post seems to be the only one - and that seems to show that the O port reduces bass slightly by lifting the mids. I reckon that Planet Waves video is definitely doctored. It's just too good to be true compared to other people's results, and, as I say, they used two guitars to do the test. Right then, over to our resident experts, what do you say?! have you fitted one?
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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#5
05-20-2012, 06:41 AM
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IMHO Its pure snake oil, If this really worked All the makers would be onboard, That being said if anyone tries it and likes the change in their guitars sound, that's great for them, I for one will pass on this gizzmo...
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#6
05-20-2012, 12:04 PM
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God! I hate it when people start claiming 'snake oil" without ever trying the component in question! Please, leave your belief engines at the door and wipe your feet before entering an opinion.
I assume it was my post which mentioned the O-Port and which spurred this thread. I use the O-Port in two of my guitars, a Martin DM and my Little Martin travel guitar. I prefer the benefits afforded those two guitars with the device in place. If you read my post in the "effect of soundhole" thread, you'll see the basic description of what effect the O-Port is intended to have. You'll also see a description of how the O-Port is intended to operate - the basic physics of the device. If you do not understand the body of a guitar as a Helmholtz Resonator, then you might have problems understanding the simple physics of the O-Port. But that is what is at work here, simple physics which date back to the Greeks. Since arriving at this forum I have detected a certain snobbery about how instruments sound along with a lack of clear understanding as to how they sound that way. Threads which ask basic questions answered by laws of physics or materials knowledge seem to be full of all sorts of mumbo-jumbo about woods and variables which are a mystery to be brushed aside in a sentence or two claiming its all about what anyone likes. I'm not about to imply the O-Port's effect will not result in a subjective impression of liking or disliking the sound. But, gentlemen, the effect is created by physics and it is easily understood if you just refer back to your high school education or know a bit of history. For one thing, such devices have been incorporated into guitars for at least the last 150 years. Without trying to sound as if I am a shill for Planet Waves, the effect of the O-Port is similar to a tuned port on a loudspeaker. The enclosed cubic volume of a cavity when vented forms a simple Helmholtz Resonator which on its own has a system resonant frequency. The volume of air enclosed within the resonator cavity is excited into motion by the pressurization resulting from the movement of the guitar's body. With a fixed low frequency cut off created by the lowest frequency produced by a six string guitar, approx. 80Hz, the cubic volume of the cavity will reach dimensions which will provide either overdamped, underdamped or critcally damped values. Those values will affect what is called the "Q" of the system. When the system is underdamped the frequency response of the system will tend towards a lumpy bass with a slightly rising frequency response above system resonance. This creates what we normally term "BOOM". Think of the example I provided in my post, a Gibson Jumbo. But this is what guitar builders were trying to create as they gradually increased the volume of the cavity in larger and larger instruments through the first half of the 20the c/. Boom stood out and made the acoustic guitar a viable solo instrument in the days before amplification. However, and I'm sure many will disagree, BOOM is a very undersireable quality if you are looking for an evenly balanced frequency response which also favors the mids, highs and the attack and sustain of those notes. BOOM is the opposite of what is desired in a recording studio due its tendency toward obscuring those upper frequencies. Therefore, BOOM is a trade off which can be unacceptable to some listeners but it is created by the simple physics of an underdamped system. An overdamped instrument would have mostly the opposite frequency response with a bit of a dip just beneath system resonance. This would lead to a slightly "jangly" sound quality from a small bodied guitar where the low frequencies have been slightly depressed in level relative to the mid and upper frequencies. The shape of the cavity is not that important other than in discussing how the shape can affect the movement of the air mass out of the cavity, the shape of the vent's throat is of primary concern. So manipulating the cubic volume of the upper and lower bouts of the guitar serves to move the air mass in desireable ways and adds to the amount of low frequency heft we hear from small parlor guitars. If you have a half way decent audio system with vented speaker cabinets, go stick your finger in the port of your bass reflex speakers. You should feel a tube with a described volume and length. This is used to tune the cavity's resonant frequency and adjust the "Q" of the system. Without this port -which has volume and length, the speaker would just have a simple hole which would allow for the enclosed volume of air to escape the cavity. This simple hole-in-the-box would be the speakers which existed before mathematics became the accepted norm for defining a speaker's system resonance, the old fashioned one note boom boxes. By adding the tuned vent to the enclosure the designer is able to create a system with repeateable results and manipluate the "Q" of the system. Many cheap speakers have been sold with a high "Q" system resonance which results in a boomy, jump off the shelf advantage over more accurate speakers. Boom sells. Think of all the dreadnoughts which emphasize bass heft lining the walls of any Guitar Center in the US. For more on why this is, read the description of the human ear's perception of bass and high frequencies as predicted by the Fletcher Munson curves as I outlined them in the post in "effect of sound hole size". The point to remember is the cavity and its vent act as a system. With a low frequency cut off defined largely by the length of the lowest string, the designer has one less variable to deal with. Now, think of blowing air across the top of an open bottle. With an empty bottle you'll have the system resonance of the full cavity which will be somewhat low in frequency. Add some water and you've changed the system resonant frequency by decreasing the cubic volume of compressed air but not changing the volume of the vent. This is the essence of what the sound hole enlargement accomplishes and this is what the O-Port also accomplishes. By adding a defined volume and length to the vent of the Helmholtz Resonator (the guitar body), the O-Port acts as a tuned port would in a loudspeaker. It's primary function is to tune the "Q" of the resonator. This changes the frequency response either just above or just beneath the system resonance of the cavity. The O-Port, however, is a simple product with defined volume and length in its own right. Therefore, it cannot be all things to all guitars. Whether the addition of the O-Port creates an over damped, underdamped or critically damped system will depend first on the cubic volume of the cavity. The adddition of the O-Port will in some cases be beneficial strictly in terms of how it affects the "Q" of the system and in some cases it will not be a good fit. The O-Port does, however, come with a money back guarantee so the idea anyone is selling "snake oil" is just simply BS. Get over yourself if that's your idea. If it doesn't work the way you would prefer with your guitar, return it and get a full refund of your money. In addition to the tuned port concept of the O-Port, its shape also acts as a horn loading device which will have its own benefits - many of which I described in the sound hole thread. When it meets the right cavity, the O-Port will be beneficial. When it is used in the wrong cavity, it will not. Whether the O-Port is beneficial to you or not would be a subjective determination which is nothing more predictable than which instrument or which strings you would prefer. Where one person will hear a less bassy sound, another person will hear a more defined sound throughout the frequency range after the insertion of the O-Port into any specific guitar. There is no way to predict what anyone will prefer when it comes to sound quality. What can be considered though, is the reticence some folks have to anything which is unfamiliar or unknown to their belief engine. Some folks are just a little too quick to start insulting others when what the other person represents is something they fail to understand and do not wish to make the attempt to understand. On this forum you'll discuss strings and woods and all forms of subjective values with little real knowledge of their effect other than you like or dislike them. Yet, when a product such as the O-Port comes along, you're very quick to complain rather than spend a few refundable dollars to try a device which might actually make your high end instruments sound even better than they already do. The physics of the O-Port make it not exclusionary to a high end isntrument, only to an instrument with which it is not a good match due to the cubic volume of the Helmholtz Resonator you own. This is, indeed, a tough crowd.
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#7
05-20-2012, 12:27 PM
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Ya know, when I bought my Walden there was a delay in getting it to me. For the troubles, Walden sent some extra goodies with the guitar for my troubles. One of the goodies was a PW O-Port. I never installed it and just threw it on the shelf where it still sits.
I actually forgot all about it till I seen this thread. Perhaps I will throw it on my Washburn for experimental purposes.... I'll get back to you on that (the Washburn is my work guitar, so not here right now). Maybe I'll make a quick video of before and after.... might be a couple of days, but now my curiosity is getting the better of me, lol.
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"Those who wish to appear wise among fools, among the wise seem foolish."Quintilian
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#8
05-20-2012, 12:30 PM
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Quote:
I share your frustration, seriously. And yes, 35 years ago I toiled for long hours trying to improve the porting and the crossover on Spendor BC1 speakers (as was used for high quality monitoring by the BBC). The results I still use today as my main Hi-fi speakers. Many thanks for your commitment (time!), detail and knowledge. I have learnt a lot from you. Much appreciated. And don't get put off by some of the comments on here - rise above it.
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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#9
05-20-2012, 03:02 PM
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Quote:
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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#10
05-20-2012, 04:49 PM
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Only in the broadest terms can I predict what will change when an O-Port is inserted into any guitar. One issue with a prediction is the lack of a standard for how a guitar should sound. In other words, the math and physics of the Helmholtz Resonator and a tuned port are working towards an ideal; tuning the system to a specific system resonance. When a speaker designer uses a port of a specific volume amd length, they are trying to accomplish specific goals. Those goals may be an over or underdamped cavity but they are trying to work toward their goal only by manipulating the volume and length of the vent after the cavity volume has been established.
What makes the guitar difficult to predict is the fact a guitar is not meant to be "critically damped" in most cases. A guitar as a musical instrument is meant to not exhibit flat frequency response where a loudspeaker has that as the ideal objective. Therefore, subjectively, you selected your guitar(s) - I'm going to hope - based upon the sound they create. Making the prediction less certain would be there are many ways to skin the cat to arrive at a desirable sound from a musical instrument. For example, I mentioned system "Q" in the above post. In a discussion of the system resonance this will determine how damped the air mass will be which in turn will create a subjective impression of how "woofy", "boomy" "tight", "dry", etc the instrument appears to any given listener. So our first problem is words do not always mean the same thing to each individual and, if we don't share a common glossary, then our communciations break down rapidly. High end audio has such a glossary developed by the man who essentially created subjective audio reviewing; http://www.stereophile.com/reference/50/ However, I've been in a discussion with a group of audiophiles on another forum who find the number of terms in the glossary to be too overwhelming and their descriptions of an audio component's musical reproduction will normally come down to the sound was too "warm" or too "bright". Those two words alone leave much to be desired when discussing audio and music but they have little interest in learning more than that. One member stated he didn't care what the glossary claimed as a definition, he got to make up whatever he wanted because it only mattered what he thought a word meant. I pray this fellow never decides to go into the field of international diplomacy. Many of the words we might use are similar between audio and a guitar because we are still describing music as the end result. However, I am unaware of any such glossary for guitar buyers. That leaves most musicians out in the cold with words that have little common meaning. More importantly, IMO, when an audio listener describes a musical event or a sound, they are dsiscussing a deviation from a presumed neutral performance - the ideal being the system does not intrude on the original sound of, say, a guitar. With a guitar, there is no neutral instrument. Guitars are selected based on their own peculiar sound qualities. Therefore, stating an O-Port might change a guitar's sound in this or that way wouldn't have much significance since you bought the guitar for that sound. If I suggested the O-Port installation would tighten the bass, would that be a desirable thing for your guitar? Maybe, maybe not. The installation of an O-Port in any guitar will alter the fundamental system resonance, there's no doubt about that. Whether there is a subjective improvement in sound quality is impossible to predict. The statement was made earlier, "If this really worked All the makers would be onboard." I would tend to disagree for several reasons. First, if you have read the article I linked to in the sound hole thread, you'll see that many builders made attempts at "improving" the quality of sound coming from a guitar by using a tuned port type device beginning well back into the 1850's. Unlike the O-Port many of those attempts made for a bulkier, heavier, less agile instrument which was not what the market was aiming for at the time. As we are all likely to know, what the market wanted was a loud guitar with the boom of a deadnought or a jumbo. Before electricity entered the guitar this is what made the guitarist the solo player in the group or projected the instrument's sound above the din of a noisey dance hall. After electricity amplified the guitar we were left with holdovers from those days of purely acoustic music. That is what most of the buyers still crave - just look at the walls of your local music shop for the number of small bodied guitars vs dreads. So I would think its safe to say many buyers of dreadnoughts prefer to have some boom in their bass - the opposite of the critically damped loudspeaker. The manufacturers are giving the buyers what they say they want. Planet Waves is simply saying they can change that sound with their device. What I assume you would prefer me to say though is, I can predict whether a O-Port will become a "match" for your guitar. Possibly, Planet Waves is the better place to ask since they know their product better than I do and they certainly must have done the math equations to come up with the most broadly usable device they could create. My answer would be, if you wish to sell the most units to the most guitar owners, what body size would you aim your design at? A dreadnought, right? It stands to reason the O-Port will benefit dreadnoughts more than OM's or O's. If for no other reason than the dreadnought style is meant to have some thump and they are ubiquitous. There are two sizes of the O-Port, one for a larger and one for a small sound hole. The smaller O-Port is also shorter which we would expect because it is aimed at smaller bodied guitars. So, as long as the sound hold dimensions of your guitar make the O-Port acceptable, the tuned port which the device becomes inside your guitar should function as advertised. My guess would be the O-Port will have the least number of desirable effects on guitars of the OM to O size which tend to lack boom in the first place. I cannot predict whether you will find the alteration to be pleasant or not. Remember, as players we don't hear what someone standing in front of the guitar will hear. Additionally, builders such as Collings offer enlarged sound holes which do many of the same things as the O-Port will accomplish. In the sound hole thread Collings is quoted as saying, "Full rich basses are complemented by clear, singing trebles with great clarity and sustain. The enlarged soundhole removes some of the "woofy" basses that so often plague larger instruments ... " As I said in that thread, "woofy" bass is what the sound hole and the O-Port are trying to improve. But sometimes "woofy" bass has been designed into the guitar by means other than the sound hole dimensions. How the instrument has been braced internally will affect the "woofiness" of the bass also. Going back to loudspeakers for a moment, a resonance in the walls of the enclosure will alter the "Q" of the system by adding a sustaining signal where none was meant to exist. Since guitars do not strive for neutrality, its quite possible the designer intended for that low frequency resonance to exist in their design and braced the instrument accordingly. That is their concept of how their guitars should sound and, if the woofy bass is being created as the result of something other than the sound hole, then the O-Port cannot address those values. Probably the best thing I can predict is the shape of the O-Port will function somewhat as a horn loaded cavity. A horn functions as an acoustic transformer smoothing the transistion of the pressure wave from a high presure zone to a low pressure zone. This gives a horn loaded system its projection and its sense of attack. By focussing the sound exiting the O-Port, the sound should always be perceived as having slightly greater projection with any instrument of any size. The apparent "speed" of the attack should also be consistently improved. Since the acoustic transformer has affected the pressure wave in positive ways, I would say most guitars using the O-Port should also have a greater sense of sustain. Does that help? Last edited by JanVigne; 05-20-2012 at 04:59 PM.
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#11
05-20-2012, 05:24 PM
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I just watched the video linked to in the op of this thread. In the video one advantage to the O-Port was said to be its elimination of hard edges created by a traditional sound hole in the thin top plate of an acoustic guitar. The issue is one of diffraction which will affect any wave length shorter than the thickness of the top plate. And, obviously, the shape of the O-Port will eliminate those edges and also eliminate diffraction which tends to give those short wave length mid to upper frequencies a hard edge. This benefit of the O-Port should be universal on all guitars regardless of body size. Unfortunately, since mid and high frequencies tend to be increasingly directional in their path of travel, this benefit is unlikely to be one the player notices easily. I would suggest, if you are going to give the O-Port a try, either have someone listen from in front of the guitar or record a before and after sound.
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#12
05-20-2012, 06:49 PM
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I blew the speaker out in my amp from feedback so I got O-Ports for each of my 12 stringers. Much less feedback now. The sound isn't much different. I noticed slightly more bass & a slightly compressed sound, which I like for fingerpicking. The volume isn't as up & down note to note so it sounds smoother to my ears.
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#13
05-20-2012, 08:33 PM
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There was an earlier discussion about these last year. Results were mixed.
See the thread: http://www.acousticguitarforum.com/f...ghlight=o-port Offhand, it didn't make me want to spend the $20.
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#14
05-21-2012, 02:32 AM
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Quote:
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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#15
05-21-2012, 03:04 AM
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BTW, does anyone know what the two size sound holes dimensions are for the so called small and large units? The Planet Waves web site is far from clear. It simply says (copied and pasted here):
Fits Soundholes from 33.75" - 35" (85.73 cm - 88.9 cm) Wha? that's a BIG guitar?! Notwithstanding the fact that those ludicrous measurements still don't mention TWO sizes. You just can't get the staff.. I need the sizes (with allowable variation) for TWO soundholes please.
__________________
Experienced guitar tech and singer/guitarist based in the midlands, England. McIlroy AJ50 Yamaha CPX-1200 Yamaha CPX-700/12 Yamaha LS16 Yamaha FG-300 Yamaha FG-580 Vox V2000-DR + electric guitars..
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