Is a horn phase coherent device?

[Davey]

Should I contact David McBean to break the news gently that he's made a mistake?

Yeah, I think you better.
That's an interesting phase response for a horn without a driver.

Dave.

 

[chris661]

To answer the OP's question: Yes, it is possible. Note the red line in the attached graph. Very, very low phase variance.

Sorry for the poor image quality-- I had to take a picture of the screen, as the original file is too large to upload, here @ the DIY.

That's the electrical phase, and the vertical scale is very narrow - it looks like it might swing from +90 to -90 on your graph.

Chris

 

[andreasmaaan]

A single sound source can (must) obviously have a phase response. I think what Patrick might have meant to say is that a single source can’t be described in terms of phase coherence.

 

[David McBean]

Oh no - this is awkward !
Here's the phase response of a 400Hz tractrix horn without a driver -
Should I contact David McBean to break the news gently that he's made a mistake ?

You are showing the phase response with a linear phase offset delay correction of 0.7 msec. Try looking at the standard wrapped phase instead.

 

[phase_accurate]

I think the phase response display with the delay in place is easier to interpret. Apart from the rising phase response at the upper end it looks very reasonable. The rise might be due to the chosen delay being slightly off.
This horn will have a group delay peak between 600 and 800 Hz BTW.

Regards

Charles

 

[Scott L]

That's the electrical phase, and the vertical scale is very narrow - it looks like it might swing from +90 to -90 on your graph.

Chris

+/- 36 degrees, at most.

 

[David McBean]

Hi Charles,

I think the phase response display with the delay in place is easier to interpret.

The option was included in Hornresp for that reason. It can however be confusing for people who are not familiar with the technique.

The rise might be due to the chosen delay being slightly off.

The offset delay correction used in the test example is the automatically-calculated default value, equivalent to the mean group delay across the -12 dB delimited SPL bandwidth. For the given example, it is the only value that completely removes phase wrapping.

This horn will have a group delay peak between 600 and 800 Hz BTW.

See attachment.

Kind regards,

David