I think the reference was to a methodology (use of standard PVC plumbing pipe and fittings) rather than a specific design:
Laying Pipe with Audio Lego
note the provenance of hosting site for above and age of the projects
Personally, I never parsed the full text of these projects to determine how much calculated math (as opposed to simple iterative "guessing") was involved.
Hmm, the PVC pipe variation would be a good way to cover all aspects of vented, TL and stepped TL, though not tapered [horn].
For sure, if you do go this route, use drivers with a tiny Vas, otherwise the pipe will need to be a large diameter = $$$ for good performance both unstuffed for ease of audibly tracking pipe action and stuffed for smooth wide BW response.
GM
For sure, if you do go this route, use drivers with a tiny Vas, otherwise the pipe will need to be a large diameter = $$$ for good performance both unstuffed for ease of audibly tracking pipe action and stuffed for smooth wide BW response.
GM
Hi,
The "idea" is presumptuous and somewhat unsound, as a big enclosure
with a small driver usually gets slaughtered by simply using a bigger driver.
In the UK I's suggest buying these :
Tibo EDGE MINI Black | Speakers Per Pair | Richer Sounds
or these :
Wharfedale DIAMOND 9.0 Black | Speakers Per Pair | Richer Sounds
And see what you can do. I'd suggest keeping width the same,
lots more height as a floorstander, and playing with the depth.
Varnished packing cardboard is great for prototypes,
especially comparing only bass loading options.
rgds, sreten.
sreten,
I think that you are missing the point of the exercise here. It is not to make great sound or even to compare this to a decent speaker. It is only a teaching tool to teach kids about a Helmholtz radiator or a simple resonating tube.. Who really care what it sounds like. just that you can change the sound by varying the length of the tube and the size of the tube radius if it goes that far. No different than filling coke bottles with water to different heights and blowing across them and hearing the different tuning of a resonant chamber. Just made another cheap instructional tool there.....
I think that you are missing the point of the exercise here. It is not to make great sound or even to compare this to a decent speaker. It is only a teaching tool to teach kids about a Helmholtz radiator or a simple resonating tube.. Who really care what it sounds like. just that you can change the sound by varying the length of the tube and the size of the tube radius if it goes that far. No different than filling coke bottles with water to different heights and blowing across them and hearing the different tuning of a resonant chamber. Just made another cheap instructional tool there.....
exercises and the brain...
...apparently exercising the brain helps its plasticity (and I can use all the help I can get).
For someone looking at getting decent or good performance at low prices they would be well advised to follow sreten's suggestions. His advise is well grounded and thoughtful (and at least as opinionated as mine). But in this case the exercise IS the exercise.
We also need to consider the tools (software, electronic and construction) and materials that Rullknufs has available. An alternative to wood and PVC piping is compressed cardboard tubing, as found in the flooring industry: usually free, easy to cut, and naturally damped.
...apparently exercising the brain helps its plasticity (and I can use all the help I can get).
For someone looking at getting decent or good performance at low prices they would be well advised to follow sreten's suggestions. His advise is well grounded and thoughtful (and at least as opinionated as mine). But in this case the exercise IS the exercise.
We also need to consider the tools (software, electronic and construction) and materials that Rullknufs has available. An alternative to wood and PVC piping is compressed cardboard tubing, as found in the flooring industry: usually free, easy to cut, and naturally damped.
Nanook,
I don't even think we are on the same page here. Just buying a set of pre-made speakers teaches what? This isn't an exercise to get nice sound, that could be done a million ways, this was to teach basic math and science, at least that is how I understood this project. You don't need much in the way of any test equipment to show that a long tube will resonate at a lower frequency than a short tube. So explain to me how what you are proposing answers the basic premise of the experiment?
I don't even think we are on the same page here. Just buying a set of pre-made speakers teaches what? This isn't an exercise to get nice sound, that could be done a million ways, this was to teach basic math and science, at least that is how I understood this project. You don't need much in the way of any test equipment to show that a long tube will resonate at a lower frequency than a short tube. So explain to me how what you are proposing answers the basic premise of the experiment?
Well, in the Swedish high-school system every student has to make a project work related to their study programme. I'm in the nature science programme which means I study extra physics, math, biology and chemistry. Biology and chemistry is not really my kind of stuff, but math and physics is fun and I'm already very interested in audio. So therefore I thought of this as a way to link audio to math and physics.
We then have until early february to finish our work. It does not have to be a product, it could be some research, a trip or something like that. And it's not the finished product that is important, it's the documentation and elaboration of the related subjects that's important if you're looking for a high grade (which I am).
Rullknufs,
We have a saying here in the US called the KISS principle. Keep it simple stupid. Meaning that the equipment needed to perform the experiment does not have to be complex. You can do that with your treatise of the math and physics behind this simple experiment. There will be much to explain with equations and physics of resonance.
The paper is more important than the apparatus.
We have a saying here in the US called the KISS principle. Keep it simple stupid. Meaning that the equipment needed to perform the experiment does not have to be complex. You can do that with your treatise of the math and physics behind this simple experiment. There will be much to explain with equations and physics of resonance.
The paper is more important than the apparatus.
Yes, but having it only on paper might make no sense to most people. I will be demonstrating my work on an exhibition and just having a bunch of papers wont be very cool, right? Therefore it would be good to construct something simple and cheap to put whats in the papers to reality, making it less abstract.
Yes,
You will have the pipes and a speaker to demonstrate the principals of the design. I imagine you also need a written paper to go with it. If you make a nice stand so the pipes can stand up then people could change the pipes and hear what you are talking about. It will be an interactive demonstration.
You will have the pipes and a speaker to demonstrate the principals of the design. I imagine you also need a written paper to go with it. If you make a nice stand so the pipes can stand up then people could change the pipes and hear what you are talking about. It will be an interactive demonstration.
Rullknuffs,
I like the simple pipe idea, be it PVC or cardboard 'carpet' rolls.
I recently brought a couple of 1.2m lengths of 3" diameter card tubes for a similar experiment.
I simply stuck the driver, a 3" tangband, into the tube, just out of curiosity. I started with just the tube, then added small amounts of absorbent, and played with their location. The audible effects were very obvious. Again, to repeat another post, you could also investigate a 1/2 wave pipe/open ended at both ends, and experiment with the driver offset.
It would be very easy to gather alot of testing data, demonstrating the effect of stuffing and pipe nodes etc. You wouldnt need a calibrated mic for that purpose, as the measurements would only be 'compared' to each other.
I would imagine that you could generate alot of subject matter to be discussed in your conclusions, and referred back to your design phase. This is where the marks are, if im not mistaken.
I had to do a similar project during my HNC studies (I made a modded Elliot P3 amplifier), and I understand your points.
The 'write-up' of the project, design selection, costing, implementation, testing and conclusions are indeed the most important. In my case, I was the only student who completed the project, and tested it.
Im normally very modest, but....I got the best mark!
The very best of luck, and I hope you now have some ideas to work on.
I like the simple pipe idea, be it PVC or cardboard 'carpet' rolls.
I recently brought a couple of 1.2m lengths of 3" diameter card tubes for a similar experiment.
I simply stuck the driver, a 3" tangband, into the tube, just out of curiosity. I started with just the tube, then added small amounts of absorbent, and played with their location. The audible effects were very obvious. Again, to repeat another post, you could also investigate a 1/2 wave pipe/open ended at both ends, and experiment with the driver offset.
It would be very easy to gather alot of testing data, demonstrating the effect of stuffing and pipe nodes etc. You wouldnt need a calibrated mic for that purpose, as the measurements would only be 'compared' to each other.
I would imagine that you could generate alot of subject matter to be discussed in your conclusions, and referred back to your design phase. This is where the marks are, if im not mistaken.
I had to do a similar project during my HNC studies (I made a modded Elliot P3 amplifier), and I understand your points.
The 'write-up' of the project, design selection, costing, implementation, testing and conclusions are indeed the most important. In my case, I was the only student who completed the project, and tested it.
Im normally very modest, but....I got the best mark!
The very best of luck, and I hope you now have some ideas to work on.
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Seems like you've understood the point
The idea of this is to teach the students to work with a project. And as you say, design selection, costing, implementation, testing and conclusions are more important than the actual result.If I were to get some tubes like this, what driver could be suitable?
I would echo another poster in saying that you should aim for as small a Vas as possible. My rough experiment used the tangband W3 1285sg. Not 'cheap' in the scheme of things though. Also the pipe being 1.2m long should have fundamental at 70hz or thereabouts, driver Fs around 100hz and low Qts. It was far from calculated in its conception. However, there are cheaper 3inch tangband drivers. Also fountek which are reasonable too. Maybe aura? Im not sure which would be the best value in Sweden though. Of course im assuming a 3 inch pipe which for me seems to be the easiest to find. Of course PVC is available in many sizes so your choice would be less limited. One thing to note is the size of the magnet. In my 3 inch pipe, the TBs fitted fine, due to the neo magnet. Unfortunately the alpair 6s i have didnt, by a small margin.
If bass and loud volumes are not overwhelming priorities then you could use a smaller driver. I have a pair of visaton FRS5X- Qts around 0.7, Fs 160-200hz. At a guess id say these would fit in domestic waste pipe, like the bath drain stuff. They cost me £6 each from lautsprecher.de.
Even with restricted bass output I believe you could demonstrate the characteristics of pipe harmonics just as well. With the high-ish Qts i reckon you would also have plenty of scope to tune WAY below Fs and use the fundamental pipe resonance to bolster the bass, even if it is 'one note bass'.
If bass and loud volumes are not overwhelming priorities then you could use a smaller driver. I have a pair of visaton FRS5X- Qts around 0.7, Fs 160-200hz. At a guess id say these would fit in domestic waste pipe, like the bath drain stuff. They cost me £6 each from lautsprecher.de.
Even with restricted bass output I believe you could demonstrate the characteristics of pipe harmonics just as well. With the high-ish Qts i reckon you would also have plenty of scope to tune WAY below Fs and use the fundamental pipe resonance to bolster the bass, even if it is 'one note bass'.
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mondogenerator,
Those people at B..E would call this extended bass response. Making a Bo.. Wave Cannon. Front firing full range with bass extension. So very hifi........ haha
Those people at B..E would call this extended bass response. Making a Bo.. Wave Cannon. Front firing full range with bass extension. So very hifi........ haha
Some research that would be very useful would be a study of the effectiveness/characteristics of damping materials. A long pipe, a speaker/amplifier/sig gen to excite the pipe, a mic to capture the output and a whole lot of different damping materials/desities/schemes in between. You could teach us some stuff.
dave
kindhornman, i called my primitive creation the Bazooka, since i just stood the pipe horizontally, driver forward, venting 1.2m behind. Had a weird polar effect lol. I guess i could have called it the Bo-zooka though
kudos to dave. At the end of the day, using a 2inch driver in domestic plumbing pipe, with variour materials is Pretty Much a plane wave tube. And to the best of my knowledge, thats exactly how the absorption of such materials, are tested.
kudos to dave. At the end of the day, using a 2inch driver in domestic plumbing pipe, with variour materials is Pretty Much a plane wave tube. And to the best of my knowledge, thats exactly how the absorption of such materials, are tested.
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Kindhornman...
...please re-read my previous post. We are on the same page:
and here was your response:
What I proposed was the most basic pipe that I know of, a piece of PCV pipe or compressed cardboard tube of a suitable dimension. The exercise is relating the project to the field of studies. Thus a simplified and inexpensive enclosure, simple mathematics that can be explained algerbraically if need be, and the use of relatively inexpensive drivers (such as the EL70s if Rullknuffs has a pair, as Dave suggests).
My comments regarding tools are both the theoretical tools and the basic hand tools that Rullknufs can use and explain. How much simpler does it need to be?
Stuff needed:
Notice no software or computer is required to do the experiments or mathematics. One could use a comp and some software for the write-up as needed. The majority of the work would be in documenting the build and the rational (mathematically) for the chosen dimensions and "tuning", and possible effects of the changes to dimensions that would result in a different result.
...please re-read my previous post. We are on the same page:
and here was your response:
What I proposed was the most basic pipe that I know of, a piece of PCV pipe or compressed cardboard tube of a suitable dimension. The exercise is relating the project to the field of studies. Thus a simplified and inexpensive enclosure, simple mathematics that can be explained algerbraically if need be, and the use of relatively inexpensive drivers (such as the EL70s if Rullknuffs has a pair, as Dave suggests).
My comments regarding tools are both the theoretical tools and the basic hand tools that Rullknufs can use and explain. How much simpler does it need to be?
Stuff needed:
- 1 pair of suitable drivers (fullrange or co-axial types)
- 2 lengths of a suitable diameter tube made of compressed cardboard or PCV to use as enclosures
- 1 pair end caps to mount on one end of each one of the tubes to allow the drivers to be mounted to (wood or PCV block offs)
- 1 pair of end caps that can have a circle cut out of them to allow the tube to have an exit, but also to ease mounting the tubes to some sort of plinth
- 1 pair of some sort of speaker plinth with feet to raise the exit of the pipes off the floor
- a few feet of some sort of reasonable internal wiring
- 1 pair of terminal cups with terminals
- a handsaw to cut the tubes
- a soldering iron, wire strippers, and solder
- the use of a jig saw or similar to cut out the openings for the drivers to be mounted and for the pipes to have as an exit
Notice no software or computer is required to do the experiments or mathematics. One could use a comp and some software for the write-up as needed. The majority of the work would be in documenting the build and the rational (mathematically) for the chosen dimensions and "tuning", and possible effects of the changes to dimensions that would result in a different result.
Nanook,
Okay, we are all on the same page then. I don't know that he has much of a budget to purchase much more than the absolute minimum of parts, so he will probably have to use what he has. I'm sure we can all point him in the direction of some free software that he can use to do simple calculations and he can also use Thiel -Small calculations for some added comparisons. Now who want to help him with the paper, just kidding.
Steven
Okay, we are all on the same page then. I don't know that he has much of a budget to purchase much more than the absolute minimum of parts, so he will probably have to use what he has. I'm sure we can all point him in the direction of some free software that he can use to do simple calculations and he can also use Thiel -Small calculations for some added comparisons. Now who want to help him with the paper, just kidding.
Steven
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