But this is an apples and oranges comparison. My statement stated a fixed gap size. If the gap changes size and the flux stays the same then the magnet had to change as well. The comparison is only valid IF the gap dimensions remain constant - as they do in the compression drivers being discussed here. The mass will not change in my example.
Force factor is BLi which is flux*length of wire*current. A 16 ohm winding will have a longer wire in the same gap so there is a higher force factor for a given current. See the earlier post like 23-30 for an 8 ohm 4 ohm woofer comparison which clearly shows the difference.
I have no idea how to wind a 16 ohm voice coil and an 8 ohm voice coil and end up with the same wire length or mass if the voice coil length is the same. Maybe you got magic I do not know about. Could you share that?
The efficiency of the formula shown calculates acoustic watts.
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Thanks for the thicker skin.
I suspect the situation is more related to an unstable amp (97%) not liking the load than the horn itself. The lighter load really helps many amps out a lot.
I do truly enjoy a good point based in reason which can allow me to be shown or discover an error. I do not like errors. On the other hand vague statements like "I do not get it therefore you are wrong" are just annoying. At this point I assume I am correct until there is a reasoned approach or a logical progression which clearly cast doubt on what was presented. I do not feel it is my job to teach anyone the basic of physics (101&102) for this forum. Gedlee made a good point but I have no idea what it was so I clarified the effect I spoke of and hope that got it. This is good and helpful so thanks for that.
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See post 23-30 for manufacturer data showing these effects.
I do not keep old data from the age of discovery as a semi would be required and what use is it anyway? All voice coil transducers work in exactly the same way and if correctly measured behave in extremely predictable ways related to those measurement.
What we've got here is a failure to communicate...
I think a problem is not understanding "thinking style" divisions - a "true" physics based analysis may be viewed as absurd by a engineer when the assumptions that are not stated differ in the two ways of thinking about the subject
for instance several people here have repeated that the engineering understanding of "changing a driver's voice coil impedance" is based on changing voice coil wire size, turns and keeping mass, dimensions the same - which results in equivalent dynamic Theil-Small parameters with an ideal transformer interposed on the electrical side
'summa persists in his "physics based" definition of keeping the same coil length and changing everything else – a different base assumption that makes "our heads hurt" on the engineering side
It may be useful to read this paper:
Theory and Practice - Thinking Styles in Engineering and Science
I think a problem is not understanding "thinking style" divisions - a "true" physics based analysis may be viewed as absurd by a engineer when the assumptions that are not stated differ in the two ways of thinking about the subject
for instance several people here have repeated that the engineering understanding of "changing a driver's voice coil impedance" is based on changing voice coil wire size, turns and keeping mass, dimensions the same - which results in equivalent dynamic Theil-Small parameters with an ideal transformer interposed on the electrical side
'summa persists in his "physics based" definition of keeping the same coil length and changing everything else – a different base assumption that makes "our heads hurt" on the engineering side
It may be useful to read this paper:
Theory and Practice - Thinking Styles in Engineering and Science
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Precisely correct and precisely what is being discussed since that what is done from an 8 ohm to 16 ohm change - the diaphragms are interchangable in the motor struicture.
The force factor goes up in the exact same proportion that the current goes down, so when driven by a voltage source there is no change in output.
Yep, read through them all. You seem to post links to manufacturer specs (Gee thanks 🙂 ) and those specs show there is no response difference between the 8 ohm and 4 ohm Eminence drivers.
You say you have your own private lab (yeah, we can all measure speakers in our private labs 😉 ). So how posting the measurements that show the distinct advantages of using a 16 ohm driver over a 8 ohm driver. If someone can not use measurements to prove their point then there isnt anything to debate.
Yes that is correct however you will notice that BL is squared and resistance is not squared so BL wins in the efficiency and Q formulas. Mass goes down also lead to exactly what happens if something is not purposefully done to make them the same.
I am sorry. I was speaking of real parts made with real wire inside of physical loudspeakers. The notion that 16 and 8 ohm motors when made using normal equipment and normal wire gauges wound on normal formers end up with the same mass, twice the resistance, and so on is not realistic. That is an engineering concept. Physics is the direct study of nature though observation. The physical part weighs less in the 16 ohm version.
I have pointed out that some manufacturers that wish there 8 and 16 ohm to be the same add mass to the 16. The rest accept the 16 ohm is going to be more efficient and better in important ways and they just do not mention it because at the same voltage level it will not be as loud anyway. See post earlier 23-30. And the I had to do some digging. Nobody wants to hear that 32 ohm speakers work better because there is a huge industry and many jobs and fake credibility to protect and power is watts is the equivalent unit to the bean in the world of bean counters. So with low voltage being much easier to deal with as if by magic we have 2 ohm voice coils and 2 ohm capable amplifiers making 1000s of watts. How all this came to be is not a mystery.
You saw the data sheets and saw the higher BL on the 8 ohm and lower mass and so on and then squinted at a marketing frequency response curve? The point was those items and not the "smoothed" curve. If those items are better BL and so on then the driver works better as a transducer.
Yes, I saw all the different values but still how does that correlate to better audiable performance? Only measurements will show this and since you understand what performance enhancements exist it would be nice to back it up with measured differences.
Are you going to tell me measurements will not show the differences?
Its not only realistic, its possible and is generally what is done. The guage gets smaller, more turns, higher resistance, same mass. Since resistance goes as area (radius squared), this too goes as the square just like Bl (since L goes linearly with radius) - it all washes out.
It's surprising how a simple question can cause so much heated debate😉
Reading though the posts the general consensus seems to be that there is no difference between a 8 and 16 ohm driver, and thinking about it in simple terms I would agree that there should be no difference.
However in the real world an 8 ohm driver needs double the current of a 16 ohm driver. All things being equal then double the cross sectional area of cables are required to transmit the same power from the amplifier with the same efficiency......
This must have an effect!
I am reminded of development work on a 12 Volt winch motor. The losses in the cables were huge! We had to use welding cables to keep any efficiency.
The 24 Volt motors were far more practical.
Reading though the posts the general consensus seems to be that there is no difference between a 8 and 16 ohm driver, and thinking about it in simple terms I would agree that there should be no difference.
However in the real world an 8 ohm driver needs double the current of a 16 ohm driver. All things being equal then double the cross sectional area of cables are required to transmit the same power from the amplifier with the same efficiency......
This must have an effect!
I am reminded of development work on a 12 Volt winch motor. The losses in the cables were huge! We had to use welding cables to keep any efficiency.
The 24 Volt motors were far more practical.
I think it's a little difficult to make that comparison. High current DC requires heavy gauge wire. Speakers are a different story.
Xoc1. True enough about the cables, but at the small currents used by a compression driver at hi-fi levels, it is not likely to be a problem.
What might be interesting, as a number of posts here point out, is the higher electromotive force cause by the higher voltage in a 16 ohm driver. That's only if the driver is actually used at a higher voltage.
What might be interesting, as a number of posts here point out, is the higher electromotive force cause by the higher voltage in a 16 ohm driver. That's only if the driver is actually used at a higher voltage.
sumaudioguy. My apologizes if I rubbed you the wrong way. That was not my intent. I did try to politely explain why members here might have legitimate questions about what you have posted. If you don't understand that, I failed in my post.
Internet forums are tough places. If you can't stand the questions, it's probably not the place for you. That would be too bad, as you seem to have a lot to share. You just have to be prepared to be questioned or challenged on some of what you say. Just ask Earl Geddes. (Gedlee)
Remember the kitchen, remember the heat.
Internet forums are tough places. If you can't stand the questions, it's probably not the place for you. That would be too bad, as you seem to have a lot to share. You just have to be prepared to be questioned or challenged on some of what you say. Just ask Earl Geddes. (Gedlee)
Remember the kitchen, remember the heat.
Sure fine and back to you. Mercy is high on my list.
It is just amazing for a persons who has never seen a speaker factory make all these claims. I would tell you to call someone and simply verify what I have said but all the people I know don't want to be bothered or have died. Paul Roth is the last of the ones I know alive and active around here and he would be super PO'ed if I gave out his contact info. I wish Paul Klipsch was still alive. I ring my old buddy up and his "no ********" button would go off like a fire alarm. He gave those out for a while... yellow background with smallish black lettering. Maybe you have seen them?
Please look at the details of BL, mass, resonant frequency and so on. The devil is in the the details. That highly integrated response curve is just that, no real detail and phase is not even shown.
Grabbing at straws I see. I wondered if it would come down to that. There is also packing density, I'm surprised that you did not bring that up. But these are all secondary effects to your point and my correction.
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