We look at speaker enclosures, sharp edges cause much discussion about wave disturbance, noise issues and complaints.
Does the little sharp edge thing over the cone of this Alum - Ceramic tweeter do anything like that?
I picked this tweeter to point at because the white and black contrast is easy to visualize.
Thanks DT
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It's all relative to wavelength, if the structural stuff over the tweeter is few millimeters in dimension, most of any "issues" would be at millimeters wavelengths. at delay of distance from sound source to the structure. So, any effects to sound is to delay few millimeters at few millimeter wavelengths.
More over, diffraction is inevitable, it's just sound going around an object or a corner. The "issue" with diffraction is that a sound source that appears at the corner where diffraction happens, which emits backwards from where the sound came from. So it's important to consider where the sound came from and where the diffraction backwave heads at. There can be diffraction in a system that is harmless and even useful if it's effect is toward some off-axis angle helping with directivity, while it might be considered an issue when the backwave is toward listening window with negative audible effects like making response vary to all angles limiting your options for toe-in for example.
I think that the particular structure here is to make path length from the tip of the dome just a teeny bit longer, perhaps with diffraction effects as well, to widen response at very top end of pass band. IOW reduce beaming.
More over, diffraction is inevitable, it's just sound going around an object or a corner. The "issue" with diffraction is that a sound source that appears at the corner where diffraction happens, which emits backwards from where the sound came from. So it's important to consider where the sound came from and where the diffraction backwave heads at. There can be diffraction in a system that is harmless and even useful if it's effect is toward some off-axis angle helping with directivity, while it might be considered an issue when the backwave is toward listening window with negative audible effects like making response vary to all angles limiting your options for toe-in for example.
I think that the particular structure here is to make path length from the tip of the dome just a teeny bit longer, perhaps with diffraction effects as well, to widen response at very top end of pass band. IOW reduce beaming.
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Are we going to discuss the pointy thingies in the middle of ring radiators too? TBH there isn’t any new thing in there and it’s all very well understood by the designers of these drivers.
Sure, there is only one thing over the cone.
Sure, also discuss the discuss the pointy thingies in the middle of ring radiators too if you like. The mouth of the JBL 075 does look sort of horn like to me. Old Too.
Did not say any thing about new.
There is a new Purifi Tweeter with a similar sharp edge thing over the cone.
We do discuss such things here. The manufactures use different names for such.
Thanks DT
Yes I’ve removed it and measured it without it.
I’ve already measured the D2904 vs R2904 on and off axis.
A picture is a worth a thousand words, and I will post some pictures/links when I’m my other computer…
I’ve already measured the D2904 vs R2904 on and off axis.
A picture is a worth a thousand words, and I will post some pictures/links when I’m my other computer…
That little piece that obstruct the emission of the apex of the dome is there for a reason.
It's a sort of a phase plug in the sense that permits to 'eliminate' the sound waves coming from the apex and not those emitted by the rest of the dome. Someone said WL, yes, because some millimeters are important in the very treble frequency, and it may happen ( indeed, it does) that some frequencies are emitted in antiphase and in phase in different areas of the dome with the same stimulus.
It's a sort of a phase plug in the sense that permits to 'eliminate' the sound waves coming from the apex and not those emitted by the rest of the dome. Someone said WL, yes, because some millimeters are important in the very treble frequency, and it may happen ( indeed, it does) that some frequencies are emitted in antiphase and in phase in different areas of the dome with the same stimulus.