Something stirs in the Undergrowth

[Nick]

You appear to have put a model aircraft propeller in front of your driver and this is giving you more tone and low level detail .

Just shows how what you think you understand can lead you into mistaken conclusions. The propeller part is just there to hold the shaped piece in the centre in front of the voice coil. Its that centre piece that causes the result, not the "blades".

[Daniel Quinn]

So its a cone shaped bung ala many manufacturers Epos , B&W, but it is not mechanically intergrated with the driver . I still have difficulty in a cone with no mechanical connection to the driver causing changes in tone and low level detail.

As the propeller parts are fixed , it must surely not be mechanically connected .

[Nick]

Again "Just shows how what you think you understand can lead you into mistaken conclusions.".

The "cone shaped bung" is called a phase plug, and while you may think its connected to the cone, in the examples you give, its not, its fixed to the centre of the voice coil, so not the part that moves.

[Daniel Quinn]

I knew it was called a phase plug .

I am perplexed by your continual criticism of what I understand , all my posts make no claims to understand a bloody thing ,

here is wiki's definition of a phase plug

What does a phase plug do on a speaker?
In a loudspeaker, a phase plug, phasing plug or acoustical transformer is a mechanical interface between a speaker driver and the audience. The phase plug extends high frequency response because it guides waves outward toward the listener rather than allowing them to interact destructively near the driver.

I remain perplexed as to better tone and low level detail and the fact it is not mechanically connected it is floating in free space in front of the driver .

[ed]

So its a cone shaped bung ala many manufacturers Epos , B&W, but it is not mechanically intergrated with the driver . I still have difficulty in a cone with no mechanical connection to the driver causing changes in tone and low level detail.

As the propeller parts are fixed , it must surely not be mechanically connected .

There is chapter and verse about this phenomena around the diy fraternity circa 2005/2006 when many people were fixing wooden phase plugs to fostex wide band drivers. The evidence of the changes this caused are legion....It even caused much debate about the efficacy of the lowther mushrooms.

go read if you have difficulty understanding, there are easily understood explanations.

edit: posts overlapped...this may or may not still be relevant.

[Daniel Quinn]

fixing

I have distilled your post to only relevant word you posted .

[pre65]

fixing

I have distilled your post to only relevant word you posted .

Why do you (Dennis) feel the need to deride a fellow enthusiast who was (quite clearly) trying to help you ?

[cressy]

A phase plug is not fixed to the driver cone in the same way a dust cap in the centre of a normal driver is. What the phase plug does is to provide a guide surface in the centre of the cone of sound that is projected from the driver. The driver output hits it and is directed in a manner dictated by its shape. It needs to be in a fixed position in relation to the cone either as Mark has done with a spider to hold it in that position, or by a fixing that runs down the centre of the voice coil former and fixes it to the driver basket, the static part of the driver. A dust cap mainly seals the driver so that nothing gets into the very tight gap between the coil and the magnet, and doesn't provide a small guide surface as it is moving with the driver, producing its own part of the cone behaviour.
The shape of the phase plug directing the driver output can alter the way it sounds by altering the behaviour of the output from the different areas of the cone. The output from one area of the cone can be markedly different from another area of the cone, and how these outputs interact with each other effects how it sounds

[Nick]

I am perplexed by your continual criticism of what I understand , all my posts make no claims to understand a bloody thing ,

Because it seems that your request for education on a subject reads as if you are at best doubtful about the original posters motives.

Eg your response to Ed trying to offer understanding.

[Nick]

I think you misunderstand the importance of "fixing" or not, what is important is does it move with the cone or not, everything else doesn't matter. If its held in place by being fixed to the outer of the speaker frame or the centre of the speaker its still not moving with the cone. I suspect you don;t know whats behind the dust cap where a normal phase plug is fixed.

This document contains information that should help

ftp://ftp.veracomp.pl/pc/logitech/docs/ ... 20Plug.pdf

[Nick]

A phase plug does not have to be fixed to the driver cone in the same way a dust cap in the centre of a normal driver is

I would replace "does not have to be" with "is not", otherwise you have a wizzer cone.

[cressy]

Done

[Daniel Quinn]

So the phase plug is having an influence .

and yet the propellers are benign ?

The phase plug guides waves beneficially . The propellers would surely diffract the waives.

I am not saying Mr PInk did not hear what he reported , i am tying to understand how sticking a propeller in front of the driver is the causal variable.

Am I to assume this is universal benefit ?

And pre aka Norm , I have my own moral code that I employ in every post I make ,I would be obliged if you could refrain from trying to question it and/or impose yours upon me , as it would appear your posting code is chaotic , ill thought out and somewhat moronic .

[Nick]

But they are not propellers, they are not aerofoil shaped, but symmetric. The map is not the territory. They are used because to fit it to the centre of the voice coil would involve removing the dust cap, and fix directly to what was underneath it, that adds more of a risk breaking the driver.

[cressy]

They will have a small effect the way mark has done it, the thin cross section presented to the driver output by the way mark has mounted them means that effect should be minimal.

If you look at the lowther mushrooms, they reflect back at the driver as part of shaping the output, so dependent on the effect you want to achieve, the blades on marks spider could have their angle altered through up to 90 degrees (so they are face on rather than edge on) to achieve that effect