AFMG Network

Jim Mobley · Member

With the update to EASE 4.3, the metaphor for SPL mapping has been changed to broad band pink noise rather than the multi-tone metaphor that was used in previous versions.

Here's a specific example, EASE has twenty-one, 1/3 octave bands; open the default Sphere loudspeaker, a loudspeaker with a 100 watt power handling. In the properties for the Sphere, click on All Off to set all bands to 0 dB SPL. Now for 1000 Hz enter a value of 100 watts in the Ele. Power column and click Apply. Note that the values remain black, also look at the bottom of the frequency response graph. See that the Max value and current values are both at 100 watts. Now pick 1250 Hz and enter a value of 100 watts there and click Apply. Now you will see the Ele. Power values turn red, but also note that the Max power value remains at 100 watts but the Current value is now 200 watts. You are applying 100 watts at 1000 Hz and 100 watts at 1250 Hz for a total of 200 watts of power. You have to distribute the power the loudspeaker can handle across the frequency range. You can do this by clicking the All to Max button and click apply. You'll see that the Ele. Power values all go to 4.762 watts which = 100/21; 100 watts divided evenly into twenty-one bands.

That's great you say, but how do I know how loud it will get? The same way you would with an SPL meter. As an example, place the Sphere in a model above a normal audience area at Z = 11.2 m (36.75 ft.). Be sure your area is the normal height of 1.2 m (3.94 feet), the speaker to area distance is 10 m (32.81 ft.). So, 1/10 = 0.1, Log 0.1 = -1 x 20 = -20, so 110 - 20 = 90 dB SPL, and if you set the map to show Direct SPL, Broadband, you'll see 90 dB-SPL directly below the loudspeaker. (You'll have to click the mouse in Peek mode, due to rounding EASE actually computes 89.8 dB-SPL directly under the Sphere.)

This change was made so that the band averaging would work correctly and to allow mapping with A-weighting.

Note that with DLL/GLL loudspeakers, the levels are listed as attenuation, so -0- is full up.

jitendra · Member

Hi Jim,

Thank you for the detailed information.
For public address system simulations should we take multi-tone or pink noise setting as generally for announcements only speech signal will be used?

Thanks
Jitendra

AFMG Pedro Lima · Forum Moderator

pink noise Wink

Infrasonic · Member

Dear All,

Need your advise please. I'm using EASE 4.4, the problem I have now is that I always get a better simulation result using multi-tone rather than pink noise. If I were to use pink noise which is the recommended setting according to manual, I would need to use 9x20W speakers at full tap, distanced at 5m, to cover an area with dimension of 4x44m, just to get an ideal SPL distribution. Whereas if I use multi-tone, I would only need to tap at 5W and I get a much better result.

Please advise and thanks in advance.

Regards,
Infrasonic

Waldemar · Member

Hi Infrasonic,

as explained in the manual, if you use multi-tone, EASE puts the maximum voltage (power) in every 3rd octave calculation. This could be wrong, since the speaker cannot perform those levels for a broadband signal.

Anonymous · Guest

In the properties for the Sphere, click on All Off to set all bands to 0 dB SPL. Now for 1000 Hz enter a value of 100 watts in the Ele.Power column and click Apply.

Note that the values remain black, also look at the bottom of the frequency response graph. See that the Max value and current values are both at 100 watts. Now pick 1250 Hz and enter a value of 100 watts there and click Apply. Now you will see the Ele.

Power values turn red, but also note that the Max power value remains at 100 watts but the Current value is now 200 watts. You are applying 100 watts at 1000 Hz and 100 watts at 1250 Hz for a total of 200 watts of power. You have to distribute the power the loudspeaker can handle across the frequency range.

You can do this by clicking the All to Max button and click apply. You'll see that the Ele. Power values all go to 4.762 watts which = 100/21; 100 watts divided evenly into twenty-one bands.

That's great you say, but how do I know how loud it will get? The same way you would with an SPL meter. As an example, place the Sphere in a model above a normal audience area at Z = 11.2 m (36.75 ft.

Be sure your area is the normal height of 1.2 m (3.94 feet), the speaker to area distance is 10 m (32.81 ft.). So, 1/10 = 0.1, Log 0.1 = -1 x 20 = -20, so 110 - 20 = 90 dB SPL, and if you set the map to show Direct SPL, Broadband, you'll see 90 dB-SPL directly below the loudspeaker.

You'll have to click the mouse in Peek mode, due to rounding EASE actually computes 89.8 dB-SPL directly under the Sphere.