Why bass management makes my life tedious

[markus]

Backpedaled? I corrected someone who had stated it was "restoring" the signal, saying that I wished people would stop using the word "restore". I can't control what other people try to claim the purpose of BEQ is, but correcting those who claim it is a restoration is certainly not at all backpedaling.

from https://www.avsforum.com/threads/th...ith-htp-1-owners-thread.3112176/post-60955027

I let people decide what they want to call it

The Bass EQ for Movies Thread

Would it not be great if you could bring back the lost bass in you favourite movies? Well, perhaps you can. By applying equalization customized for each movie during playback, it is possible to dig out some of the low bass lost due to filtering and processing in the studio.Why Bass EQHow to Bass ...

data-bass.ipbhost.com

 

[3ll3d00d]

Maybe the misunderstanding comes from the BEQ thread itself: https://www.avsforum.com/threads/bass-eq-for-filtered-movies.2995212/

It's a restatement of https://data-bass.ipbhost.com/topic/285-the-bass-eq-for-movies-thread/?tab=comments#comment-4000 in stronger terms (same @Kvalsvoll who posts on this site).

The whole debate about whether it is intent or not always struck me as completely pointless but some people love those debates.

 

[markus]

The whole debate about whether it is intent or not always struck me as completely pointless but some people love those debates.

As pointless as any attempt in faithful sound reproduction...

 

[3ll3d00d]

The *debates* (on forums such as this) around that are similarly pointless yes, 000s of pages of forums threads on the topic that go nowhere.

 

[aron7awol]

I let people decide what they want to call it

The Bass EQ for Movies Thread

Would it not be great if you could bring back the lost bass in you favourite movies? Well, perhaps you can. By applying equalization customized for each movie during playback, it is possible to dig out some of the low bass lost due to filtering and processing in the studio.Why Bass EQHow to Bass ...

data-bass.ipbhost.com

Once again, not written by me and not representative of my opinion. You and I actually agree that it's not a restoration, so I'm not sure why you called me out specifically to try to lump me into the side of the argument that I'm vehemently against.

 

[markus]

Once again, not written by me and not representative of my opinion. You and I actually agree that it's not a restoration, so I'm not sure why you called me out specifically to try to lump me into the side of the argument that I'm vehemently against.

I just noted that you seem to be the minority (or only one?) in the group of BEQ enthusiasts that does NOT think that BEQ would be some kind of restoration process.

 

[audio2design]

At the other end of the scale, if I ran a 40Hz signal 180 degrees out of phase into the left/right pair, someone who's totally in to their bass management region at that frequency would get literally SILENCE as a result of that signal. Without bass management, you'd get a wide stereo bass effect.

ACOUSTIC SUMMING (dB) / BASS MANAGED (dB)

L = 74.0 / 74.0
L+R = 77.9 / 80.0
L+C = 79.4 / 80.1
L+C+R = 82.2 / 83.5
LS+RS = 77.2 / untested
L+C+R+LS+RS = 85.1 / 88.1

As you can see, this test only spanned up to 5.0, but as the speaker count increases, so does the discrepancy. By the time you're in 7.1.4 or 9.1.6 the difference is really quite large. Maybe I'll run a real world test of that if I get time...


/Rant

1) you would either hear 40hz or not. You don't get "wide" bass at 40hz. You can't hear directionality at 40hz. If you can you are hearing higher frequencies / distortion.

2) those differences don't seem that bad at all. Not many would run wide range speakers for most of the additional channels so it won't get worse, at least normally. I would be more worried about them running small speakers wide range and distorting.

 

[aron7awol]

I just noted that you seem to be the minority (or only one?) in the group of BEQ enthusiasts that does NOT think that BEQ would be some kind of restoration process.

That is not at all what backpedaling means, but at this point, I am willing to agree to agree (on it not being a restoration) and move on.

 

[audio2920]

1) you would either hear 40hz or not. You don't get "wide" bass at 40hz. You can't hear directionality at 40hz. If you can you are hearing higher frequencies / distortion.

OK you obviously know more about mixing in multichannel formats than me then.

I didn't think phase angle between speakers introduced high frequency and distortion.

The magnitude of discrepancy goes up with higher channel counts, that was an an old test I did in 5.1. But granted, whether it's *significant* to an individual would depend whether they were concerned about bass lift or cut of several dB below 80Hz.

Edit: as I've said before, this isn't the most offensive issue ever. But in a world where we're striving for studio to home translation, it's just another thing to be aware of I think.

Regarding whether you can hear direction at 40Hz, I'm not saying I could point the source with my eyes closed, particularly at a spot frequency, but when there's multiple bass sources of non-identical content, the way it sums in a room gives it spatial qualities, which I really don't think are related to "higher frequencies" somehow being generated by phase relationship of multiple bass sources. But in any case, this particular effect ("mono bass") has been discussed to death on the Internet over the last 2 decades or so and there's still two camps, so it's not gonna reach resolution here. Although obviously it has a relationship to this post about summing in room vs summing in electronics, it wasn't my intent to open another discussion on bass directionality.

 

[Frontino]

IMO, if downmixing had never been used and surround audio had always been utilized as an enhancement, rather than a complete canvas of director's intent, we might be in a simpler situation.

To explain further, if the center channel contained all the fundamental sounds needed to follow a movie and the other extra channels were used just to improve the immersivity, instead of containing exclusively essential audio elements or for hard panning, then a master print could be simply downscaled into smaller audio system by mere channel discarding:

No sub = LFE discarded
No surrounds = surround channels discarded
Stereo speakers = center channel in dual mono.

 

[Chromatischism]

IMO, if downmixing had never been used and surround audio had always been utilized as an enhancement, rather than a complete canvas of director's intent, we might be in a simpler situation.

To explain further, if the center channel contained all the fundamental sounds needed to follow a movie and the other extra channels were used just to improve the immersivity, instead of containing exclusively essential audio elements or for hard panning, then a master print could be simply downscaled into smaller audio system by mere channel discarding:

No sub = LFE discarded
No surrounds = surround channels discarded
Stereo speakers = center channel in dual mono.

It's an interesting idea, but we wanted realism, and that meant putting full-range sound all around us, so here we are. You are essentially proposing a world where we don't have Atmos, DTS:X, etc. Or at least a world where it's not allowed to put anything below (for example) 80 Hz in any speaker channel. Maybe that would help.

 

[Frontino]

Of course, channel discarding would not be the answer to all kind of problems coming from mix translation to any room size, but at least we would no longer get those coming from downmixing aggressive surround tracks, which already saturate at full scale digital in each channel.

My proposal would just require a different mixing approach.
Surround audio should be thought of like surround video. Imagine a cinema room having multiple screens all around you and each one corresponding to a speaker of a surround audio system (I remember something like that done for The Maze Runner). The central front screen should be the main one, showing everything necessary to follow the story and not be missing anything from the director's vision, whilst all the other screens should be used for additional immersivity (think of the LFE as the floor screen, for example).

Now, when the time would come to transfer that master into a single front screen version, if downmixing, you would essentially be superimposing each screen's video track over the others and get a cluster eff of an incomprehensible mess. So, of course, the most logical approach would be channel discarding, as in retaining the main front screen and omit all the others.

 

[Frontino]

I'd like to talk a bit about one problem (amongst many) I find when mixing films in surround sound: Bass summing.

What if we placed speakers in a different manner, as in increasingly distant from us and from each other, without changing the recommended angles, but calibrated at same SPL from the listening position?

My idea would be the logarithmic spiral:
https://en.m.wikipedia.org/wiki/Logarithmic_spiral

Starting from the Left Side Surround as the closest and continuing with the Left Rear Surround, ending with the Left Front as the farthest speaker.
Of course, the audio processor must not perform any phase adjustment, otherwise there'd be no point in this.

Wouldn't this tame correlated sound summing?