Originally Posted by Conrad Nash
I explain it to people differently. It has nothing to do with changing the response of your system; BEQ is about restoring the content back to where it should be/was. That's why it goes on the input side of the minidsp, you're affecting what's sent in to the subs. The in room EQ that you apply to get your system to play back frequencies at the appropriate volume is about output and is specific to your equipment in your room.
So your system will only be able to play back the signal it's given. If its not given anything <20Hz then it won't have anything to play back. BEQ is about restoring that content.
Where I hear most people go wrong is that, pre-BEQ, they have a really aggressive house curve (big boost down low) because they're used to watching movies with no low content. When you add in BEQ and restore that content, the boost is too much. Think of an aggressive house curve like a generic BEQ filter. The key there is to EQ closer to flat and use BEQ.
In short, you should add the BEQ filters to the inputs of all bass reproducing devices in your room - subs, TR devices, BOSSs, etc. so that they all get the correct signal.
The output EQ that you've applied to them might need to be tweaked now that you're listening to restored content, but they're independent of each other.
Originally Posted by DesertDog
Nice explanation! In my opinion you shouldn't run an aggressive house curve with BEQ. My take now is to EQ the room flat with a small increase in the lower frequencies to compensate for how our ears work. BEQ then takes care of the heavy lifting and is tailored to the track. Everything feels more balanced now and doesn't get boomy.
I may be in the scenario of having too much boost, but am still evaluating. We watched The Invisible Man last night, and I had to turn it down, mainly because my daughter was complaining, but the bass may have been sligthly hot on that particular title in my current configuration. Basically, as noted below, JW3 sounds phenomenal, and I want all movies to sound that good, but maybe that is not possible. I know you guys will probably tell me to dial it back, but when I use an MSO calibration at a lower level than noted below for BEQ tites, JW3 does not have the same impact. Here is the background on my system:
Subwoofer 1: 2x 4000ULF-ST behind the screen wall.
Subwoofer 2: 2x SubMersive HP on the side walls.
Subwoofer 3: SubMersive HP+ Master & Slave on the rear wall.
miniDSP Setup Information
I am using two subwoofer EQ presets; one for non-BEQ titles, and one with BEQ titles. I use the fantastic Multi-Sub Optimizer (MSO) software to generate the biquad PEQ filters for my three sub channels (2 paired subs per channel, so 6 subs total) on the miniDSP 2x4 HD outputs. The fourth output goes to my BOSS platform.
Pre-EQ Combined sub response
I discovered that inverting the side wall subs (slightly behind me) resulted in much better combined response, before EQ. I have to thank Steven Smith's video on REW multi-sub EQ (Link at the end of this post) for that inversion test tip. Below is the result of my sub inversion test; I tested inverting all three, even though #2 and #3 are the only subs behind me.
I just recently ran various MSO optimization options again, due to sub inversion testing noted above. This required taking the measurements MSO requires again and running optimizations. Since the measurements are taken one time and used for multiple optimization scenarios, it is easy to test multiple options with MSO.
Note that I am using a target curve that is included in the MSO filters. They provide an example Harman target curve (from the Welti paper, I presume) that I just loaded into the MSO optimization options section. Several months ago I attempted playing around with the default curve and the best results were when I left it at default.
Here is the current post-MSO response I am using for BEQ titles
, which merges with the REPO. This is 17.23 dB over reference, based on my calculated REW sweep level.
Here is the current post-MSO response I am using for non-BEQ titles
, which merges with the REPO. This is 19.90 dB over reference, based on my calculated REW sweep level.
The Listening Test Process
After I load the gain, delay, and PEQ filters for each optimization, I test the various option these days using three titles:
The Conjuring 2 (16 Hz hit at 0:14:53) This is problematic in my system, and the level of concern varies dependent upon my overall subwoofer system boost above reference.
John Wick 3 (lobby shootout, chapter 13) This movie does not really have any issues of concern in my system, and only gets better when pushed harder. Perhaps this is an anomaly with a phenomenal soundtrack and a phenomenal BEQ?
Fury (tiger battle starting at 1:18:30) This scene is very hot for both the sounds inside the tanks when they are hit and when they hit the Tiger. Again, the level of concern varies dependent upon my overall subwoofer system boost above reference.
I welcome any input that is not simply "Turn it down".