This is a good starting point for reading: http://en.wikipedia.org/wiki/Glass-reinforced_plastic
Best, Markus
I must be missing something - I know all about reinforced plastics, laminates, etc. I don't understand why I would want to use that on "the form", what would that do? The form is steel and alluminum, what would plastic do? Somebody is misusing a term somewhere.
Are you talking about coating the outside of the enclosure with a laminate? One would most deffinately not want to use fiber reinforced material for that - inside sure, but NOT outside. Epoxy coating on the outside would be the best for this as you can get it very smooth and very very hard. There is no limit to how thick that it could be made either. One could get 1/4" of epoxy on the outside without much trouble. But this procedure is very much like the original Summas which used a core of MDF, CLD and carbon fiber. A lot of trouble, even more expense, and not a whole lot of advantage.
Are you talking about coating the outside of the enclosure with a laminate? One would most deffinately not want to use fiber reinforced material for that - inside sure, but NOT outside. Epoxy coating on the outside would be the best for this as you can get it very smooth and very very hard. There is no limit to how thick that it could be made either. One could get 1/4" of epoxy on the outside without much trouble. But this procedure is very much like the original Summas which used a core of MDF, CLD and carbon fiber. A lot of trouble, even more expense, and not a whole lot of advantage.
I don't know what the trouble and costs are as I never worked with glass reinforced plastic. But the advantage would be that the user get's something more like this:
An externally hosted image should be here but it was not working when we last tested it.
Which is way easier to mount and doesn't need adjustments. And that's something which is expected from an end users point of view.
Best, Markus
Thats injection molded. Poor quality parts (depends on lots of factors of course), dirt cheap piece cost, but the tooling costs would be about $50,000 - $100,000. It's very expensive to use reinforcement fillers in injection molding so its virtually never done.
My process uses room temperature cured, room temperature poured, gravity feed with a free surface. Most manufacturing engineers would tell you that it wouldn't even work. It's extremely simple, extremely cheap tooling, but the parts are highly inconsistant. That's what they are.
Buy a thousand and I'll injection mold them for you.
My process uses room temperature cured, room temperature poured, gravity feed with a free surface. Most manufacturing engineers would tell you that it wouldn't even work. It's extremely simple, extremely cheap tooling, but the parts are highly inconsistant. That's what they are.
Buy a thousand and I'll injection mold them for you.
That's not what I'm talking about. I'm talking about your waveguide as a single part. Whatever it is made of and whatever the production steps are to produce it most cost effective doesn't matter.
I just proposed doing it in GRP. It's extremely simple, extremely cheap tooling, AND the parts are highly consistant.
If you would offer the waveguide (plus foam plug) as a single part, sales to the "real" DIYers that have all tools (router, etc.) would probably increase dramatically. I heard of people buying JBL horns for hundreds of dollors each
Grant my the right to manufacture and sell a thousand "Gedlee"-waveguides and foam plugs and let's see what happens
Best, Markus
I just proposed doing it in GRP. It's extremely simple, extremely cheap tooling, AND the parts are highly consistant.
If you would offer the waveguide (plus foam plug) as a single part, sales to the "real" DIYers that have all tools (router, etc.) would probably increase dramatically. I heard of people buying JBL horns for hundreds of dollors each
Grant my the right to manufacture and sell a thousand "Gedlee"-waveguides and foam plugs and let's see what happens
Best, Markus
gedlee said:
There are places that can do single pull molds for a lot less than 50,000 dollars. You could probalby have your waveguide molded for under 10k in the US as long as you weren't going to make more than a few thousand parts. Which you just implied above was the case.
They can even put the fancy texture on there--not that you want it.
case in point: www.protomold.com though they can only do 3" deep parts I believe. Still, there are others out there.
brings down the break even point fast.
Matt
I got addicted to sanding so here's the 5th and last coat (really):
Best, Markus
An externally hosted image should be here but it was not working when we last tested it.
Best, Markus
markus76 said:
Thanks for the Günther Theiles paper, much appreciated, If this paper is replicated, it looks like this would undermine many of the standard "engineering" models of phantom-image localization, particularly the localization assumptions made in digital compression algorithms.
A small percentage of audiophiles can't seem to hear conventional phantom-image stereo at all - when you push them a little further, it seems that they never experience image fusion, and always hear two speakers, no matter how well-set-up the system or where they sit. Many of them become aggressive mono enthusiasts, which I guess makes sense if they can't experience stereophonic sound in the same way as the rest of us. If learning plays an important role in localization and phantom-image formation, this group of listeners might have a subtly different way of processing acoustic information.
The thing that I kept wondering as I read (part of) the paper is why it isn't better known. The only reason that I could think of is that it didn't stand the test of time in its analysis. I have still not read it completely, but I did agree with the introduction about the misapplication of many ideas in psychoacoustics to the "stereo" problem. I think that he had his concerns well placed, and I'm curiuos as to how well founded his hypothesis is.
The main problem with these math models is that the solution is only for one specific point. Away from the specific location, the effects are most likely worse than without such solution.
From a market point of view, if anyone is allowed to do it, then no body will invest to promote it.
From a consumer point of view, most probably do not feel the difference is necessary becasue they have no desire for more realistic reproduction.
The most realistic reproduction is simply record at the ear and playback using headphones. Headphones are so popular these days it should be really cool such sensation can produce.
From a market point of view, if anyone is allowed to do it, then no body will invest to promote it.
From a consumer point of view, most probably do not feel the difference is necessary becasue they have no desire for more realistic reproduction.
The most realistic reproduction is simply record at the ear and playback using headphones. Headphones are so popular these days it should be really cool such sensation can produce.
You are talking about binaural recordings, and they certainly are amazing.
http://www.noogenesis.com/binaural/binaural.html
http://www.noogenesis.com/binaural/binaural.html
Hello Lynn, I've never heard of anybody not capable of summing localization. But if that's true this would offer a big opportunity for further research on summing localization. Do those people localize correctly in a natural sound spaces?
I thought that everybody knows about that paper - Theile wrote it nearly 30 years ago! You guys should definitely communicate much more. The website of Theile (and Wittek) is http://www.hauptmikrofon.de
Dummy head recording is dead because the ear of a dummy head doesn't correspond well enough to the ear of a listener (it has compatibility issues with speaker playback too). The characteristics of ones ear (plus head and torso) is as individual as a fingerprint. E.g. I own a Beyerdynamic Headzone Pro and it doesn't work for me.
Best, Markus
The most important part is the material of the head. The heads I've seen do not have the same absorption characteristics as human flesh. You do not want to record from inside the ear, rather just at the mouth of the ear.markus76 said:
I'm not sure what the Headzone does, but if it implements a HRTF, then it doesn not work very well because the original recording method is unkown. I have listened to similar technology during ITSEC in Orlando a few years ago, and agree it's not very impressive.
I have recorded with mics at my own ears and let others listen to the recoding on a Minidisc. Localization is second to none. However, noise levels were much higer and there were some background sound that was more pronounced which I suspect was related with mic linearity and mic design. I do plan to research this a bit more.
One thing that I have also tried is holding a pillow in front of my face to reduce interaural effects while using speakers, and localization was improved. Instruments recorded at the sides will actually extend outside of the speakers.
I am familiar with Dr. Thiele and I have met him, I just was not familiar with the thesis. His current areas of interest are not of much interest to me which is why I don't have much familiarity with his work.
My interest in psychoacoustics is also quite recent. When I started in loudspeaker design the problems where so far from anything at the psychoacoustics level that I didn't consider it very important. But as I refined the designs I found that I was getting into areas where psychoacoustics would be a determining factor. That and my wifes interest in sound quality.
My interest in psychoacoustics is also quite recent. When I started in loudspeaker design the problems where so far from anything at the psychoacoustics level that I didn't consider it very important. But as I refined the designs I found that I was getting into areas where psychoacoustics would be a determining factor. That and my wifes interest in sound quality.
soongsc, it doesn't work in a general sense. It works for you but if someone else has to hear with your ears then his perception is highly disturbed.
You can read a lot on the matter in Begault's book.
Best, Markus
You can read a lot on the matter in Begault's book.
Best, Markus
Heh, the HRTF head tracking phones that I listend to at ITSEC was technology spinoff from NASA. But really, others that have listened to my binaural recordings felt amazed rather than disorientated, and these people were in the same hall chatting as I did the recording. But since the mic is located at the mouth of the ear instead of in it, the effects of the ear difference is reduced significantly.
There was an interesting technology that allows focusing music into a narrow beam, now if that can be narrow enough with the speakers being able to track the listeners head, this might be an interesting experience.
One issue I think we should keep in mind is what LinkWitz mentioned about localization during this presentation:
http://au.youtube.com/watch?v=VC-sxvNzC8I
The reflections. This is an important cue even in Binaural reproduction when using HRTF, but normally ignored in the process.
BTW, if I recall correctly, HRTF data was taken using a hard head of absorption characteristics much different than the normal human head. If this is true, then validity of the HRTF is questionable.
There was an interesting technology that allows focusing music into a narrow beam, now if that can be narrow enough with the speakers being able to track the listeners head, this might be an interesting experience.
One issue I think we should keep in mind is what LinkWitz mentioned about localization during this presentation:
http://au.youtube.com/watch?v=VC-sxvNzC8I
The reflections. This is an important cue even in Binaural reproduction when using HRTF, but normally ignored in the process.
BTW, if I recall correctly, HRTF data was taken using a hard head of absorption characteristics much different than the normal human head. If this is true, then validity of the HRTF is questionable.
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