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The Low Frequency Content Thread (films, games, music, etc)

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SME, are you boosting the low end with BEQ for those movies you mentioned? JW Fallen Kingdom needs a big boost down low to extract the deep stuff.

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On 1/12/2019 at 11:49 AM, Joelmister127 said:

Ah I see, so do you think that is where the 3-5hz content is mostly? Probably to make the audience as shit scared as Tom Cruise was trying to get to the helicopter hahaha!

Honestly I'm not sure, choppers are usually around 7Hz, as you mentioned previously there were some moments where you can just feel pressure or a really quick pulse,  I didn't make note of exactly when those happened.

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3 hours ago, Pradeep said:

SME, are you boosting the low end with BEQ for those movies you mentioned? JW Fallen Kingdom needs a big boost down low to extract the deep stuff.

No BEQ applied for any titles in that post, and I gave my subjective impressions.  It seemed to me that many of the smaller effects in JW had decent ULF including some in the single digits.  I presume the larger effects are more strongly filtered (which is consistent with my experience), and these effects dominate the appearance of the PvA.  If this is indeed the case for JW, then BEQ is likely to give mixed results rather than across-the-board improvement.  Whether there is an improvement on-net may be a matter of opinion and may depend on the playback system too.  For example, the biggest effects may get the right amount of ULF, but the smaller effects might end up with too much ULF.  A lot of people may be OK with that.  I prefer to prioritize correctness above 20-30 Hz before worrying about ULF at all, because IMO the higher frequency stuff is a lot more important.  (This is a key point I probably didn't emphasize enough in some of my recent posts in which I criticized BEQ in which the same EQ is applied to all the channels to make the channel-sum PvA data look prettier.)

I should also clarify that I experience ULF on my system a bit different than I think a lot of people do.  Even though my subs have plenty of output and I'm on a suspended floor, the floor doesn't actually move or vibrate much at all.  I rarely get wobbles, and usually only with long duration content at specific frequencies that resonate with my floor (there's a scene in "Star Trek" that I know of).  However, I definitely notice a difference with and without ULF, and I experience it as much or more in the tactile domain.  Basically, I get a lot of chest and body cavity sensations with my bass in general, and the ULF affects those sensations in ways I detail in the next paragraph.

First, I need to point out that even if a soundtrack is filtered, one can still "hear" and "feel" the ULF content that was part of the original sound design in many cases.  That's because such content almost always occurs in conjunction with higher harmonics and/or amplitude modulation, which clues the brain into the missing fundamental.  Of course the filter still adversely affects the *quality* of the sound and tactile sensation.  For movies that are obnoxiously humped, you often get a kind of droning in the 20-40 Hz range (depending on where the hump is) that undulates at the lower (missing) fundamental frequencies.  For example, a helicopter filtered this way might deliver a kind of sloppy "woob-woob-woob-woob" sound and sensation, beating at 7-11 Hz (or whatever), even though the content at the actual fundamental frequency has been filtered away.  Without the filter however the sound and sensation are much tighter and more firm.  It's more of a "thD----------thD----------thD----------thD---------thD---------", where the dashes emphasize the dead space between pulses and the capital 'D' emphasizes that there's still lots of weight, even though it's very tight.  The filtered version may seem heavier, but the unfiltered version is much more natural and realistic.  In general, the lowest frequency undulations in a soundtrack seem much more articulate and *palpable* without a filter.

Of course the experience may be very different on a system that struggles to accurately recreate the non-ULF frequencies, which is most of them.  For at least some people, the 7-11 Hz beating of the helicopter rotor may be completely missing without high SPL reproduction of the actual 7-11 Hz component, in which case I would expect people to prefer the ULF boost despite potential harm done to the rest of the spectrum.  As such, I kind of gave up arguing my concerns about the quality of the BEQs posted on AVSForum (as opposed to those done by @maxmercy and posted here on DB) because I realize those BEQs probably *do* improve things for a lot of people, especially those with TTs/MAs that may otherwise be idling.

For me personally, I (believe I) have extremely high accuracy across the spectrum (bottom to top), and I definitely notice degradation to the non-ULF bass frequencies.  Indeed on a good soundtrack, I don't really hear "bass" isolated from the rest of the spectrum, unless it's specifically called for in the score or in the scene (such as when sound systems are depicted in cars or clubs).  What I hear are synergistic full-band sounds, some of which induce physical sensations that can be quite strong and sometimes intricate.  The bass is just part of the sound and sensation.  Significant degradation anywhere in the spectrum ruins that synergy, so I do what I can to preserve it.

5 hours ago, Pradeep said:

Honestly I'm not sure, choppers are usually around 7Hz, as you mentioned previously there were some moments where you can just feel pressure or a really quick pulse,  I didn't make note of exactly when those happened.

Spinning "chopper" blades may indeed have a fundamental at 7 Hz, but the "chop" has a very broad spectrum with content all the way into the treble.  The sound of a sine wave of 7 Hz is a very smooth undulation, one that requires obscenely high SPL (or a vibrating floor) to perceive.  However, that's nothing like the "chop" of a helicopter blade which is a much tighter, more abrupt sound and sensation.  The 7 Hz part is probably the least important part of the spectrum from a perceptual standpoint.

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Thanks for the explanation SME.  I'm working on deploying dedicated subs for all bed channels (and eventually heights), so that my sub out is just LFE, with no redirected bass. Goal is to be reference capable to at least 20Hz on all channels.

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2 hours ago, Pradeep said:

Thanks for the explanation SME.  I'm working on deploying dedicated subs for all bed channels (and eventually heights), so that my sub out is just LFE, with no redirected bass. Goal is to be reference capable to at least 20Hz on all channels.

Dedicated subs for each Atmos output channel?  That's pretty ambitious!  I can't recall, but I thought Atmos heights were specified to be limited bandwidth?  Assuming they were, I also don't recall if the bass management was supposed to be done by the playback processor, the authoring tools, or by the mixers themselves.

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On 1/17/2019 at 4:44 PM, SME said:

Dedicated subs for each Atmos output channel?  That's pretty ambitious!  I can't recall, but I thought Atmos heights were specified to be limited bandwidth?  Assuming they were, I also don't recall if the bass management was supposed to be done by the playback processor, the authoring tools, or by the mixers themselves.

Over on AVS BassThatHz routed the Atmos channels from MI: Fallout to his bed speakers and found extended bass present to at least 20 Hz. Apparently Atmos channels are capable of full range like the surrounds. It's tempting to treat them as just small effects speakers but clearly there's a lot of content there.

I won't be at the dedicated Atmos subs stage for a while, still need to save the pennies for a Motu 16A to take care of sub crossovers for all the beds first. Then I'll be out of outputs and will need to expand, perhaps a 24Ao as I won't need anymore inputs. Definitely not a cheap path but not approaching Trinnov pricing either.

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@SME

I know you were looking for a high efficiency surround speaker that wasn't compromised into trying for deeper extension, looks like these might be what you were looking for?

https://www.avsforum.com/forum/155-diy-speakers-subs/1514289-coaxials-another-diy-group-project.html

"15" Specs: Fs: 39.3hz QM: 12.12 Vas: 259.2 liters Cms: .249 mm/N Mms: 66.1 g SD: 856.3 cm^2 VD: 348.0 QE: .33 Re: 5.05 ohms Le: 0.60 mH Bl: 15.68 Tm QT: .33 SPL: 98.6 1w/1m Mmd: 51.7 grams"

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7 hours ago, Pradeep said:

Over on AVS BassThatHz routed the Atmos channels from MI: Fallout to his bed speakers and found extended bass present to at least 20 Hz. Apparently Atmos channels are capable of full range like the surrounds. It's tempting to treat them as just small effects speakers but clearly there's a lot of content there.

Interesting.  Does the AVR do bass management on those channels or just pass the content through?  Or can one choose between "small"/"large" to enable/disable bass management for Atmos speakers?  It'd be weird if they just let the content go through.  I'm sure that'd cause a lot of distortion, wouldn't it?  I hope they at least provide the "large" option being that all my bass management is done downstream of the AVR with the matrix processing to optimize the crossover  EQ and delay of each channel across the available subs.

8 hours ago, Pradeep said:

I won't be at the dedicated Atmos subs stage for a while, still need to save the pennies for a Motu 16A to take care of sub crossovers for all the beds first. Then I'll be out of outputs and will need to expand, perhaps a 24Ao as I won't need anymore inputs. Definitely not a cheap path but not approaching Trinnov pricing either.

I'll also be feeling the pain of only 16 output channels on my 16A if I push to Atmos.  My front stage speakers are 2-way active, and I am using 4 different sub channels.  I'm thinking I may end up doing 7.x.2 with 6 outputs used for the fronts, 4 used for the surrounds, 2 for the ceiling speakers, 3 sub channels and 1 channel for the Crowson.  That's a painful compromise to make.  At least I don't need 4 ceiling speakers.  It just doesn't work with the room, and with only one row of seats and the quality of phantom imaging I am able to get after optimization, 7.x.2 will probably be great.

7 hours ago, Pradeep said:

@SME

I know you were looking for a high efficiency surround speaker that wasn't compromised into trying for deeper extension, looks like these might be what you were looking for?

https://www.avsforum.com/forum/155-diy-speakers-subs/1514289-coaxials-another-diy-group-project.html

"15" Specs: Fs: 39.3hz QM: 12.12 Vas: 259.2 liters Cms: .249 mm/N Mms: 66.1 g SD: 856.3 cm^2 VD: 348.0 QE: .33 Re: 5.05 ohms Le: 0.60 mH Bl: 15.68 Tm QT: .33 SPL: 98.6 1w/1m Mmd: 51.7 grams"

Thanks, but my point was actually that I *can* compromise deeper extension, and I want to because that's the only way to really get the most efficiency in the upper bass / low mid frequencies where I typically need headroom for EQ boost.   These speakers go up near the ceiling, which provides a lot of extra boundary gain below the suckouts.  All of my speakers, which are placed near walls, are EQed down quite a bit below 120-150 Hz or so.    I don't like spending $$$ on amp power, so I want a coaxial with high efficiency, low mass, and moderate displacement capability.  Most coaxials are designed to be used as full-range speakers, and therefore give up efficiency for extra displacement and/or bass extension that I don't need.  Some others are strictly mid-range drivers and don't have enough displacement.

The T/S specs on that 15" look real nice.  AVSForum appears to be broken for me ATM.  OTOH, I was looking at a 10" with similar efficiency, albeit less extension.  I think it was the B&C 10CXN64.  Hopefully I'll be able to find someone who sells it when the time comes.

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On 1/17/2019 at 1:44 PM, SME said:

Dedicated subs for each Atmos output channel?  That's pretty ambitious!  I can't recall, but I thought Atmos heights were specified to be limited bandwidth?  Assuming they were, I also don't recall if the bass management was supposed to be done by the playback processor, the authoring tools, or by the mixers themselves.

All outputs from immersive audio formats are full range. The playback system handles the bass management. It is up to the mixer(s) to decide how much bass content goes to which location. While rare, it is totally possible to have full range content output from any speaker position, including the overhead speaker positions.

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15 hours ago, SME said:

Interesting.  Does the AVR do bass management on those channels or just pass the content through?  Or can one choose between "small"/"large" to enable/disable bass management for Atmos speakers?  It'd be weird if they just let the content go through.  I'm sure that'd cause a lot of distortion, wouldn't it?  I hope they at least provide the "large" option being that all my bass management is done downstream of the AVR with the matrix processing to optimize the crossover  EQ and delay of each channel across the available subs.

I'll also be feeling the pain of only 16 output channels on my 16A if I push to Atmos.  My front stage speakers are 2-way active, and I am using 4 different sub channels.  I'm thinking I may end up doing 7.x.2 with 6 outputs used for the fronts, 4 used for the surrounds, 2 for the ceiling speakers, 3 sub channels and 1 channel for the Crowson.  That's a painful compromise to make.  At least I don't need 4 ceiling speakers.  It just doesn't work with the room, and with only one row of seats and the quality of phantom imaging I am able to get after optimization, 7.x.2 will probably be great.

Thanks, but my point was actually that I *can* compromise deeper extension, and I want to because that's the only way to really get the most efficiency in the upper bass / low mid frequencies where I typically need headroom for EQ boost.   These speakers go up near the ceiling, which provides a lot of extra boundary gain below the suckouts.  All of my speakers, which are placed near walls, are EQed down quite a bit below 120-150 Hz or so.    I don't like spending $$$ on amp power, so I want a coaxial with high efficiency, low mass, and moderate displacement capability.  Most coaxials are designed to be used as full-range speakers, and therefore give up efficiency for extra displacement and/or bass extension that I don't need.  Some others are strictly mid-range drivers and don't have enough displacement.

The T/S specs on that 15" look real nice.  AVSForum appears to be broken for me ATM.  OTOH, I was looking at a 10" with similar efficiency, albeit less extension.  I think it was the B&C 10CXN64.  Hopefully I'll be able to find someone who sells it when the time comes.

Processors with Atmos/DTS:X allow you to set the heights as small with variable crossover or large, like the bed channels. So no problems obtaining full range signals for downstream processing.

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