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Stereo Bass using subwoofers

youngho

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you can do a similar analysis yourself on any mix, in fact i would welcome it. below is one of the surround. I think your interpretation is valid, but at the same time so little things create sub-bass content below 40Hz to be 'recorded' by a microphone and mixed. The LFE channel is mostly generated rather than 'recorded' by an effects studio.

I just find it so strange that the industry would 'bass-manage' thinks like voices, instruments .etc instead of relying on the end device to actually do the bass management.

Also what's wrong with Deadpool? it's a really finely produced movie with a gigantic budget.

View attachment 158767
I'm at work currently, but I'd just add the following comments:

I've generally seen the term "High-Fidelity" used with respect to music reproduction, whether stereo or multichannel, not so much for movies, especially action movies. I've seen Deadpool but don't own it.

I believe that Soundmixer's point about bass management is still valid, since your example regarding Deadpool does not seem to show that this HT mix is NOT bass-managed. You might also read his post regarding the topic here.

Young-Ho
 

abdo123

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In this document by Floyd Toole, he explores this very idea in the second picture on page 10 and its accompanying text. He measures the response of five identical full-range speakers in different locations, and shows the response of each one. This is depicted below.

View attachment 158771

At some frequencies, there is a 40 dB variation between the measured bass responses as shown. This difference in bass response is entirely due to room effects. So it is one thing to listen to the mix using a similar configuration as that used by the mixer (if indeed that is true), and quite another to hear what was heard in the control room in the bass region.

a person who is rich enough to buy a JBL M2 for each one of their speakers would have enough money to build the room from the ground up so low frequency issues are minimized and you would only need to few PEQ filters to deal with the big axial modes below 100Hz.
 

HighImpactAV

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I have never ever seen a movie mix that is bass managed, it's almost always that it's there is upward slope towards 40Hz with F10 of 20Hz or so.
Few nights ago i watched Deadpool, here is a spectrum analysis of the center channel, doesn't look bass managed to me!

So yeah, please substantiate your claims because it looks like you're either a big phony or very confused.
Soundmixer didn't say the mix is bass managed on the disc. He said "every studio I know of that does HT mixes does them on a bass-managed system. All Atmos tracks are mixed and mastered on a bass-managed system for both the cinema and home environment (emphasis mine)." In other words, the Atmos studios aren't using full range speakers. This directly contradicts your statement that "the optimal home cinema setup is to have each speaker running full-range." If the studios don't use full range speakers, then why is that the optimal home cinema setup?

Soundmixer also said, "considering there is not much bass information below 40hz in the front main speakers and not much (if anything) below 60hz in the surrounds, there are zero reasons to have five full-range speakers and a sub as a system." You then proved this with your Deadpool center channel analysis.
 

abdo123

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Soundmixer didn't say the mix is bass managed on the disc. He said "every studio I know of that does HT mixes does them on a bass-managed system. All Atmos tracks are mixed and mastered on a bass-managed system for both the cinema and home environment (emphasis mine)." In other words, the Atmos studios aren't using full range speakers. This directly contradicts your statement that "the optimal home cinema setup is to have each speaker running full-range." If the studios don't use full range speakers, then why is that the optimal home cinema setup?

Soundmixer also said, "considering there is not much bass information below 40hz in the front main speakers and not much (if anything) below 60hz in the surrounds, there are zero reasons to have five full-range speakers and a sub as a system." You then proved this with your Deadpool center channel analysis.

I appreciate your input, you're probably right, my bad! I know however of few studios where they actually use full-range speakers for everything.
 

Soundmixer

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I appreciate your input, you're probably right, my bad! I know however of few studios where they actually use full-range speakers for everything.
I would be curious as to what studio does this. In Hollywood, the folks that do what I do (Home media mixes i.e streaming and disc) do not use full-range speakers. I don't know anyone among the Hollywood (or Bay Area) studios that do.
 

abdo123

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I would be curious as to what studio does this. In Hollywood, the folks that do what I do (Home media mixes i.e streaming and disc) do not use full-range speakers. I don't know anyone among the Hollywood (or Bay Area) studios that do.

2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
 

Soundmixer

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I think your interpretation is valid, but at the same time so little things create sub-bass content below 40Hz to be 'recorded' by a microphone and mixed. The LFE channel is mostly generated rather than 'recorded' by an effects studio.
Ummm, not all content in a soundtrack is recorded by a microphone. I have a HUGE library of sound effects that I use, and that does not require a microphone at all. As a matter of fact, every studio has a HUGE library of pre-recorded sound effects that we can manipulate in all kinds of ways to create below 40hz signals. The only time you "record" a sound effect with a microphone is when you need a very specialized sound that is not already in your library. Even if it is "recorded" we can manipulate it in all kinds of ways in the studio.
 

Soundmixer

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2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
2L doesn't do movie soundtracks, and neither does Lindberg
 

abdo123

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Ummm, not all content in a soundtrack is recorded by a microphone.
Well not to be a prude but everything would have to pass through a microphone at one point (unless it's some synth samples), and it makes sense to reproduce the input of one full-range microphone with a point source speaker that is capable of doing full-range as well.
2L doesn't do movie soundtracks, and neither does Lindberg
can you share with us how much does that change exactly? in terms of setup and workflow at least.
 

Pdxwayne

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2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
I looked at the link and see that he also uses one sub, in addition to the 7 woofer systems. Those 7 woofer systems already very capable. I wonder why he still added a sub. To fill in the 20 to ~25hz region?

Also, I wonder what are the crossover points from speakers to woofer systems to sub.
 

abdo123

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I looked at the link and see that he also uses one sub, in addition to the 7 woofer systems. Those 7 woofer systems already very capable. I wonder why he still added a sub. To fill in the 20 to ~25hz region?
he says in the video that the sub is to hear what the customers would hear once he generates the LFE.
 

youngho

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I looked at the link and see that he also uses one sub, in addition to the 7 woofer systems. Those 7 woofer systems already very capable. I wonder why he still added a sub.

Also, I wonder what are the crossover points from speakers to bass modules to sub.
From the case study that was included in the link: "...with a 7380A subwoofer handling the LFE. Additionally, an 8320A compact two-way nearfield monitor sits atop the 7380A, to provide an upwards frequency extension above 120 Hz. This acts as a checkpoint into the true content of the LFE channel before it is distributed." LFE is a separate channel, so the subwoofer is used to check that content, not crossed over from the bass modules.

I believe that the answer regarding the W371A crossover is a little complicated. From the manual on the Genelec website, if you care to look around a bit: "Selecting Crossover Regions W371A calibration enables selecting the crossover frequency ranges. Your selections of the ranges are affected by room acoustics, W371A and listening locations. You may want to avoid notches in the monitor response. The default crossover range is 150-250 Hz. You can select a higher range up to 300 Hz and no narrower than 50 Hz wide. The measurement curves and subjective evaluations may guide your preferences as well as your choice of the W371A operating mode. When the W371A is positioned behind a large console obscuring the upper front woofer, a low crossover range below 250 Hz is advisable." Also, "Operational Modes The W371A can radiate low frequencies in several different ways. The most suitable mode depends on application, room and requirements for the size of the sweet spot. The user can select and run the setup of W371A in all the modes and audition to determine the preferred mode for his situation. To indicate the quality of the final alignment, GLM software displays a flatness score and a correlation score after the calibration. These scores can be used to gauge the best choice for the operational mode given the system placement in the room. However, subjective evaluation by listening to the calibrated system is highly recommended in order to evaluate the final setup choices. The operating modes are: Complementary mode where the two woofers operate independently to implement a flat frequency response; this is the default operating mode. Directive mode uses the two woofers simultaneously to create continuous directivity matching with The One three-way coaxial monitoring loudspeaker; this mode enables the system to maintain constant directivity down to very low bass frequencies.Null-steering modes use the two woofers simultaneously to enable a directive mode where the direction of minimum output (null) is set toward a problematic orientation in the room – enabling this mode reduces back wall, side wall or floor reflections."
 

Soundmixer

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can you share with us how much does that change exactly? in terms of setup and workflow at least.
Nobody should have to explain this to you, it is fairly obvious. The workflow obviously has more steps in movies than in music, we mix differently because we have a picture to mix to, and music does not. Most movies are mixed in a dubbing stage to be played back in a large theater and are "adapted" to home media. That does not happen with music. Movie soundtracks are monitored on a bass-managed system, and music usually isn't. This means we don't need five full-range speakers in our mixing rooms.

Well not to be a prude but everything would have to pass through a microphone at one point (unless it's some synth samples), and it makes sense to reproduce the input of one full-range microphone with a point source speaker that is capable of doing full-range as well.

Yes, everything does, but you missed the part about being able to manipulate what is recorded by that microphone. Also, it makes no sense at all to do the latter considering you may have hundreds of effects tracks to mixdown.
 
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youngho

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sarumbear

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2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
Nice to see “subwoofers” used as part of each speaker instead used for bass management. Those are basically split enclosure 4-way speakers, each.

Genelec did all that research to realise that Revel Salon2 is the ultimate solution :)
 

sarumbear

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The standard practice of precluding redirected stereo bass reproduction is consistent with this research only in having discovered little argument favoring stereo LFE, certainly not below 40Hz, nor for main channel stereo bass <40Hz. However, for greater enjoyment of much existing and new content, there is compelling argument in recognizing significant spatial perception in the previously ignored octave 45~90Hz, and therefore for binaural bass management and subwoofers.
This to me clarifies why I feel that 3-4 way floor-stander speakers, which are often produce bass to 40Hz or below, are better in creating a stereo soundstage then stand-mounted speakers in a 2.1 configuration. In my view, the latter is a cost-effective solution, hence I expected it to be inferior. If you want to recover the missing bass response, you have to use two subwoofers, each next to one of the stand-mounters (2.2 configuration) where the low frequency constrained woofer of the stand-mounter is augmented with a subwoofer. However, as you now use more floor space than a pair of floor-standers, why bother? Besides, you are still constrained with positioning the subwoofers as you would with the floor-standers.

Subwoofers were invented to reproduce effects in cinemas. The channel that feeds them are called LFE: Low Frequency Effect channel. It was never intended to be used in music. Audio (as in Hi-Fi) industry have high-jacked them in order to sell cheaper book-shelf/stand-mount speakers first then subwoofers as an extra. They are simply tools to extend sales.
 
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Thomas_A

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2L is the one that comes first to mind because of the interview they did for Genelecs. Morten Lindberg the guy who is in the video won a Grammy Award for best immersive audio album in 2020!


5_MORTEN_L__Genelec.png
I am sure there are many examples. One of the "extreme" ones I know of is Studio Blue in Stockholm. Monitors with 4x8.5 inch woofers each and 4x15 inch vented subs. In-room (i.e. including room gain) max SPL 139 dB at 20 Hz.

1684261590034.jpeg
 

EJ3

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Curious as to others who have compared mono and stereo sub signals in their setups? What were your experiences?
I have a pair of passive dual 4 Ohm voice coil )wired to be 2 Ohms)12' (FR 20-80 Hz) subs in ported cabs that are floor firing. My mains sit on top of the subs with a 3 degree wedge tilting them slightly upward. I am running one NAD 2200 in stereo 4 ohm mode. I cannot say what it puts out into 2 ohms (though it will run 2 Ohms). At the time of testing AMIRM did not have a good way to test the NAD 2200 at 2 Ohms. He did test it at 4 Ohms resulting in this:
index.php

In 2 Ohms (which it is designed to handle, it should be more). So power is adequate. They are running in the stereo configuration. I can SOMETIMES determine a L or R pan on bass that would be mostly signal between 40 Hz & 80 Hz. Below that, I have no clue as to what channel it is in. By virtue of the subs being under the mains, they help with room modes. If I run them mono (having done this) they have increased volume sensitivity.
 

youngho

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This to me clarifies why I feel that 3-4 way floor-stander speakers, which are often produce bass to 40Hz or below, are better in creating a stereo soundstage then stand-mounted speakers in a 2.1 configuration. In my view, the latter is a cost-effective solution, hence I expected it to be inferior. If you want to recover the missing bass response, you have to use two subwoofers, each next to one of the stand-mounters (2.2 configuration) where the low frequency constrained woofer of the stand-mounter is augmented with a subwoofer. However, as you now use more floor space than a pair of floor-standers, why bother? Besides, you are still constrained with positioning the subwoofers as you would with the floor-standers.

Subwoofers were invented to reproduce effects in cinemas. The channel that feeds them are called LFE: Low Frequency Effect channel. It was never intended to be used in music. Audio (as in Hi-Fi) industry have high-jacked them in order to sell cheaper book-shelf/stand-mount speakers first then subwoofers as an extra. They are simply tools to extend sales.
Hi, I would suggest some theoretical advantages beside profits, as you outline above.

Subwoofers are typically positioned on the floor, so lower than typical bass drivers on many floor-standing speakers. As such, they may possibly avoid or ameliorate one SBIR effect. Roy Allison's designs often had the bass driver positioned close to one (or more) boundaries for that reason. Significance of floor bounce has been debated before already (my own personal feeling is that typical microphone positioning for various sources may not "accurately" capture what one would experience in terms of floor bounce if sitting at realistic listening position relative to the actual source in the actual venue, based on what I've seen).

Careful positioning of bass sources could also result in mode cancellation or even some degree of correction, a la Welti, Geddes, Fazendi, etc.

They can also be positioned further away from the satellite speakers, so if more laterally, could potentially benefit from Blumlein aka stereo shuffling effects, if in stereo.

Furthermore, if positioned along lateral walls, could possibly enhance perception of envelopment, a la Griesinger, etc.

Positioning constraints are potentially different than with floorstanding speakers, as i outline above.

Hence, I regard it as on oversimplification to say "simply tools to extend sales," likely depends on multiple factors in personal preference.
 
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