AFMG Network Forum

d6ha · Member

Hi all,

I'm working through the column loudspeaker example in the EASE SpeakerLab User's Guide, Section 2.14.2.3 (Frequency Shading), and my result does not match Figure 2-193.

I followed the procedure exactly:
- 8 drivers, 115 mm spacing, ideal point (omni) sources
- 1st-order Butterworth low-pass filters by driver pair: outer 4 drivers at 500 Hz, next pair at 1 kHz, one center driver at 2 kHz, remaining center driver unfiltered
- Signal routing via the "Frequency Shading" input configuration

The guide's Fig. 2-193 shows the Minimum Vertical Beam Width narrowing smoothly toward the high end (up to ~16 kHz). My result instead reaches a minimum near 2 kHz and then widens sharply, with the -6 dB metric breaking down (running off scale) above ~4-5 kHz. This seems physically consistent with the strong shading leaving essentially the single unfiltered center driver active at high frequencies (i.e. approaching omni), so I'd expect the beamwidth to open up, not keep narrowing.

Below is my vertical beamwidth result:

Questions:
1. Was Fig. 2-193 generated from exactly the settings described in §2.14.2.3? If not, what settings were actually used?
2. Is there a known erratum for this figure/section?

Thanks for any insight.

AFMG Frank Siegmann · Member

Hi,

Could you please send your .xglc SpeakerLab project to support@afmg.eu for review? That would be helpful.

AFMG Frank Siegmann · Member

A minor change has since been made to the calculation algorithm, which is causing the discrepancy in the beam width.

However, this is merely an example in the user' manual intended to illustrate the method, not a “real-world” scenario.