Split... Stevens speaker design

It was definitely a good post. And I would definitely like to meet you some day as well. :bye:

He has brought forth a lot of good information on other threads. And I did respect his manner in this discussion, up until he started making those baseless accusations. I was rather surprised at that. It's too bad he won't admit that he is wrong.

BTW, you still need to let me know what you think of my idea. :detective: I figure you would have the knowledge to let me know what problems would be present, and what causes them.

 

I've spent a lot of time talking to him on the phone about different stuff. That boy is long winded, but a very nice and smart guy.

BTW, you should have brought up my idea to Dan. I have discussed this with him, so he knows about it. But maybe you guys could have taken the idea much further than where it is now. Plus it would be kind of neat to know that two of the leaders in the industry are talking about one of my ideas at CEMA. B)

Very similar, but different. I think my idea wouldn't need multiple drivers or a very large horn. In fact I think I can get by with something very small. Air pressure will be supplied by the fan/compressor, and the single high excursion driver would just excite the moving air to produce the music. What's nice is frequency response could be adjusted by changing the fan speed, and could make up for any nonlinearity in frequency response from the "exciter".

What limits bandwidth in drivers? Cone area, inductance, and limited excursion. I figure cone area is taken care of by the fan, inductance is taken care of by the small driver, and the use of a large excursion driver should provide plenty of low frequency extention. But probably to make it practical, a subwoofer would be needed.

What I'm not sure about is any problems with wind noise in the tube, or anything else I don't know about will be present. I read on JL Audio's web site that if I round over the front of the tube, I shouldn't have that wistling noise. But would it sound muffled? If so, what would be causing it?

For all those that aren't privy to this, here is a picture of what I am talking about:


The fan is on the left, blowing into a tube. A small, high excursion driver is mounted perpendicular and excites the moving air coming from the fan. This hopefully produces a highly efficient full range driver free from IMD.

Please give me your thoughts.

 

You guys sure do have sick minds. I just figured I could learn a lot from him.

This really wasn't about hearing differences in speaker wires really, but what size speaker wire to use for sub. It also got into the debate of running ground wires all the way to the battery.

BTW, if you want one of the most technical discussions on RCA's, check this thread out. It's Dan discussing different RCA's noise resistance with people like David Navone and many other very intelligent people. It's a very good read.

 

It is probalby because I didn't explain where this idea came from on this thread.

The idea is to have it work similar to a wind or brass instrument. In those instruments, someone provides the air (the fan) and either uses their lips or a reed to stimulate that air (the speaker). The benifit is that the speaker will be able to play many more frequencies than the instruments, and therefore hopefully be able to work like a full range speaker.

I figured the backside would have to be enclosed somehow to get rid of unwanted noises. I know you can find fans that are VERY quiet, so I don't think that will be a factor. The other option if it came down to it would be using compressed air to either reduce noise or produce enough air pressure if needed. Unfortunately that would be somewhat unpractical.

 

That's what I figured, that the fan would have the greatest effect on amplitude, and not the "exciter" (speaker). So maybe the fan part should work more like a servo motor and be hooked up to the amplifier. I know that servo drivers can't work in high frequencies, but if it isn't producing the sound, but just the "excursion", then maybe it would in this sense. Did I just invent the first full range servo driver? :blink:

 

I think the Cyclone proves that you can't get high frequencies. They are limited to sub bass frequencies. I figure the "exciter" will vibrate the air, producing those small changes in pressure Geo mentioned above.

 

Now that I think about it, I don't think it needs to have the "fan" be a push pull arangement. With musical instruments, they provide a constant outward pressure, not in and out. Well this would work the same way. Remember with higher frequencies, the pressure differences are much less. And when you think about it 3 dimentionally, it still works. What happens is that the exciter pushes on the air that is moving in front of it. This slows it down a little, sometimes moreso than others. This will effect the pressure of the air moving out, and produce sound.


If it helps, this is Dan's reply to my idea:

As I told him, cathedral size tubes don't work well in kick pannels.

 

Very good analogy. But I think instruments prove that you can produce "AC" out of "DC" by using some sort of controled exciter (lips or reed and controled holes to change air speed). Air speed in the instruments effect the frequency played, but they are limited to very few "notes". You could almost think of them as digital with a poor DAC. A speaker isn't limited to those notes and acts more analog, so it should be able to produce the full frequency response.

The point of this was to figure out a way around IMD. I figured if you could make something that has the precision of speakers, but would produce frequencies down to hopefully 100 Hz (if not lower), then you will eliminate MANY problems you find in seperate speakers. I know you are a big fan of point source designs, so you should know what I mean. :yes: The point is to get closer to a perfect reproduction of the source material.

I suppose what you would get is similar to a horn loaded driver. The benifit is that you won't need the horn, and efficiency, bandwidth, and frequency response hopefully will be increased. I suppose it would be similar to adding more excursion to that horn loaded driver so low end and output are increased to reduce the throat and mouth size, but without the problems that may come up if you did that to an HLCD.

Does that make sense?

Would that be a description of how instruments play? And honestly, is that much different in how music is in reality? Does a HLCD produce two different frequencies at once? Or does it play one frequency, and another so fast as to make it sound like they were played together to our brains? From what I see of a graph of music, it is one line that moves up and down, quickly or slowly to reproduce all the different frequencies and harmonics in the source material.

Or is my thinking on this wrong? It definitely could be.