Near-field measurements are a quickie to give some idea of resonances and such. In no way are they intended to show the true response of the speaker. Otherwise, i would not be needing the Klippel NFS! So while I appreciate the offer, there is no more that I like to do for that section of the measurements. As it is, it is rather time consuming when the port is on the back and such.
No I don’t mean true response. Of course not.
I agree that on the low end of port or passive radiator- it’s true contribution to the bass can’t be measured in the nearfield; the diffraction of the cabinet causes the baffle step loss; and what happens at 1m is slightly different at 2m or 3m, in a non reverberant (anechoic) field. Luckily the NFS does that but for you, so you don’t need to do any software based corrections for that.
I’m talking about the top end.
You’ve probably mused as to what causes a resonance- is it a port or is it a driver a bit of or both?
This must be a headache and extra work annotating resonances. So I wonder whether it’s even worth including a nearfield graph?
For instance, a nearfield of a tweeter (ie. mic up up almost touching it) only shows what the dome material is doing. Not the surround, or tweeter housing, the waveguide or the baffle.
Similarly a nearfield of a port or woofer is only accurate up to 4311/diameter of port/cone in inches. For instance, a 6.5” midwoofer has a typical cone diameter of 5”. So a nearfield (ie. 1-2cm from the cone) is only good up to 4311/5= 862 Hz or so. Everything higher than this is inaccurate and usually disregarded by loudspeaker designers..
If we take a measurement at an arbitrary distance like 10cm; that even creates more confusion because it’s not really a near field and not really a far field. Double confusion.
So have you considered blurring the regions that are inaccurate? Or truncating the graphs?
Sometimes I think bad data can be worse than no data.
I stopped posting measurements that may be misinterpreted. Not because it’s only wrong, or that it further causes confusion and perpetuates it, but because it create 101 questions that I have to followup.
But maybe you’ve learnt to ignore those questions better than I have.
For those following along, I’m not talking about nearfield or midfield or farfield in the context or studios monitors or listening distances.
I’m talking about testing the sound source (tweeter, midrange (if any), woofer, port or passive radiator) etc.
Hopefully you didn’t lose the (FR) plot.
BR,
Thanh