Cone or dome speakers are pistonic by design up until cone breakup which is where the cone or dome acts in DML mode. The cone or dome shapes were chosen because they are stiff structures that resist break up. This was the leading engineering principle for some time then research led speaker designers to acknowledge break up happened and to try to control break up. The BBC did a lot of basic research on this and developed cones with a curved rather than a straight wall and used plastic rather than paper, Bextrene was the favoured material for some time.
Every part of the speaker system directly effects sound quality. In looking at the details of exciter design I have found in the literature that even small changes to voice coil design can affect the sound e.g. the choice of material for the Bobbin, the type of glue used to adhere the voice coil wire, the method of adhering the bobbin to the suspension. Every element of the speaker build affects the sound to a greater or lesser extent.
Burnt.
Every part of the speaker system directly effects sound quality. In looking at the details of exciter design I have found in the literature that even small changes to voice coil design can affect the sound e.g. the choice of material for the Bobbin, the type of glue used to adhere the voice coil wire, the method of adhering the bobbin to the suspension. Every element of the speaker build affects the sound to a greater or lesser extent.
Burnt.
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@chdsl
“Look at the exciters we have. The voice coil is restricted of any motion. Paste the exciter to a table and you have music.”
Not quite. The suspensions for exciters are very stiff but that’s because the exciters are designed to impart an impulse to a surface rather than move the surface. If they had no motion at all there would be no sound.
Burnt.
“Look at the exciters we have. The voice coil is restricted of any motion. Paste the exciter to a table and you have music.”
Not quite. The suspensions for exciters are very stiff but that’s because the exciters are designed to impart an impulse to a surface rather than move the surface. If they had no motion at all there would be no sound.
Burnt.
Hello Chdsl
The pistonic behavior of a cone speaker is the first intention in its principle. The "break up" which is the same as DML occurs in the upper end of its frequency response.
It is confusing for the brain (at least mine) to mix time and frequency representation. When you say "how many sounds", you refer I think to what the brain feels which is the result of the SPL (pressure) variation in the ear through the filter bank which is the cochlea (one input,, many outputs). When the variations are slow it is a low pitch sound going out of the lowest frequencies filters of the cochlea, when the variations are fast, it is the highest frequencies (to write it short). A transient (very fast change of pressure) will fire all the outputs. A sinus in its very first periods will fire an important range of filter and then if it continues to emit, only the one corresponding to its frequency. Time is necessary to get an information of frequency.
The possibility of information from the piston movement is not one as you mention but cover all the sound (frequency) range a human can cover; in the same way the voltage coming to any analog connection in an audio signal does. The value to see over the time is not the voltage then but the speed of the cone (ok not sure its exactly the speed... I am not fully physics graduate!). The way the speed change over the time will change the output of the cochlea as the output of the bar-graph of an audio analyzer feeding by an analog voltage.
The cone is not like an organ for which a pipe able of only one sound and its is the combination of all the pipes that makes the result.
DML behavior doesn't help in the understanding of all of that because we speak often about modes which is the description of the membrane at a certain frequency so after a time long enough to be in a steady state. In a DML only some areas will emit sound for a given frequency while in a cone before the breaking up, all the surface contributes to it.
I hope the examples here will help...
Christian
I’m not going to be allowed to forget that am IThey must have very difficult b***ches Burnt
Eucy
Well if you are going to be formal about it
Yes, we Brits specialise in antiquated words to confuse and confound. It’s a gift.
Burnt
How many sounds can a speaker produce at the same time? Virtually any number as it turns out. It won't exactly be 10, 20 movements in the same direction, but rather any number of sine waves of different frequencies and amplitudes superposed on each other. The lower curve shows the motion of a speaker voice coil (and former and cone and dustcap) playing two sounds (i.e. frequencies) at the same time.
Eric
The workings of a cone driver have been known for many years.
Here G A Briggs talks about a free edge cone they used to make.
I believe he liked the sound (I have not re- read the book yet).
The main problem was the cost of aligning the cones by hand.
Getting back to the idea of slits in the cone.
I am wondering if the sound and performance would be similar to this fee edged cone , although the free edge would be on the side slits instead of the surround area.
Last night again, I was thinking instead of sleeping, mainly about a sort of phase plug shape in the centre to match the shape of the cone.
This would give a shape in the centre similar to that of the rubanoide ,where most of the hf is produced .
A sort of reversed whizzer shape.
These are all just thoughts in my head at the moment.
If I still had my old units to hand I would have had it up and running by now.
It might not work, although I can't see why it wouldn't work as a midrange, tweeter unit.
I will add it to my list of things to do, I have other interesting audio things to do in the new year.
Hopefully at least one will work ?
Steve.
Here G A Briggs talks about a free edge cone they used to make.
I believe he liked the sound (I have not re- read the book yet).
The main problem was the cost of aligning the cones by hand.
Getting back to the idea of slits in the cone.
I am wondering if the sound and performance would be similar to this fee edged cone , although the free edge would be on the side slits instead of the surround area.
Last night again, I was thinking instead of sleeping, mainly about a sort of phase plug shape in the centre to match the shape of the cone.
This would give a shape in the centre similar to that of the rubanoide ,where most of the hf is produced .
A sort of reversed whizzer shape.
These are all just thoughts in my head at the moment.
If I still had my old units to hand I would have had it up and running by now.
It might not work, although I can't see why it wouldn't work as a midrange, tweeter unit.
I will add it to my list of things to do, I have other interesting audio things to do in the new year.
Hopefully at least one will work ?
Steve.
Attachments
There's a visual 'pistonic' motion in "standard" speaker drivers, and that's all that's there about that. Bobbin as the piston is not what's making the sound/music.
Anyway, in the Rubanoide matter, the French guy must've pinched Haddock's ideas/patents, maybe those patents were already expired by then. I don't know, if the French guy has any patents. But, this idea of curved planes giving out good sound from a point source had existed very much earlier. A Telefunken speaker Arcophon 5 and Arcophon 3 had been on sale around 1929-1932. So, Haddock must've pinched from Telefunken. Anyway, we all do that.
Anyway, in the Rubanoide matter, the French guy must've pinched Haddock's ideas/patents, maybe those patents were already expired by then. I don't know, if the French guy has any patents. But, this idea of curved planes giving out good sound from a point source had existed very much earlier. A Telefunken speaker Arcophon 5 and Arcophon 3 had been on sale around 1929-1932. So, Haddock must've pinched from Telefunken. Anyway, we all do that.
Sorry, I have a problem that I can't solve
I bought the new dayton exciters those with the plastic support that allows it to be screwed to the exciter, the problem is that the adhesive system is very resistant but when I screw the exciter to its support at low volume I hear a strong rubbing and croaking due that goes away or gets worse I put the vibrating plate vertically if I touch the wires which are very soft the body of the exciter moves slightly and it starts to croak, I don't understand how to stabilize it
I bought the new dayton exciters those with the plastic support that allows it to be screwed to the exciter, the problem is that the adhesive system is very resistant but when I screw the exciter to its support at low volume I hear a strong rubbing and croaking due that goes away or gets worse I put the vibrating plate vertically if I touch the wires which are very soft the body of the exciter moves slightly and it starts to croak, I don't understand how to stabilize it
That is far from all there is about that, I wish it were that simple. Standard speakers are pistonic up to the break up frequency than then enter DML mode. Due to the complex mix of frequencies in music, as Eric’s note on frequency modulation shows, there is nothing simple about pistonic modulation and to add to the complexity cones can be and often are in both pistonic and break up or DML modes at the same time.
On bobbins I think if you read it again you will find that wasn’t what I said.
Burnt
chdsl,
Can you explain what you mean? I don't understand what you mean by either statement.
Eric
pixel1,
Which exciter did you get? Many of the Dayton models have that feature.
If you place the panel horizontal do you hear the "croaking"?
Eric
What is the model number?
Because it doesn't make sense. It's like saying glass doesn't bend.
Bobbin is a perfect word for a French guy! (FR=bobine)View attachment 1119824
I played with old wooden bobbins making them into tractors with a rubber band and a match stick. Rubber band was cut out off a bicycle tube. We had many ideas using those empty bobbins those days.