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Post by lesliew on Apr 26, 2017 15:25:54 GMT -5
As for 7.2.6, etc, etc, remember the source material needs to be coded for it in the first place; otherwise one needs an external DSP to split the signal into the additional speakers. Slight ambiguity there :- Every Atmos disc since the very first release has been coded for 24.1.10 The decoding however is limited to what a particular avr/prepro supports
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Post by aviolentgrace on Apr 26, 2017 15:50:57 GMT -5
24.1.10... So, only a single LFE channel? That seems... odd.
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Post by goozoo on Apr 26, 2017 16:01:41 GMT -5
As for 7.2.6, etc, etc, remember the source material needs to be coded for it in the first place; otherwise one needs an external DSP to split the signal into the additional speakers. Slight ambiguity there :- Every Atmos disc since the very first release has been coded for 24.1.10 The decoding however is limited to what a particular avr/prepro supports Thanks for the clarification. I did not know that the channel count was already this high for UHD dics.
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fattykidd
Sensei
It's ok.. I have an et-3.
Posts: 122
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Post by fattykidd on Apr 26, 2017 16:08:54 GMT -5
24.1.10... So, only a single LFE channel? That seems... odd. Not really.. Show a source that is coded for 2 separate lfe channels.
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Post by lesliew on Apr 26, 2017 16:38:59 GMT -5
24.1.10... So, only a single LFE channel? That seems... odd. Yep, a common misunderstanding is that there is more than 1 LFE channel, Just remember : The number of subwoofer channels a processor supports is independent of the LFE channel. LFE & Subwoofer are not infact interchangeable Multiple subwoofer channels can be derived from lots of different forms of hocus pocus, but usually produced by combining the LFE track with upto any of the 6 surround channels.
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Post by Mark on Apr 26, 2017 16:51:00 GMT -5
24.1.10... So, only a single LFE channel? That seems... odd. Not really.. Show a source that is coded for 2 separate lfe channels. Does the XMC-1 count? True 7.2 audio channel paths with stereo bass management and post processing for the ultimate cinema and stereo listening experience. Fully independent crossover settings for fronts, center, surrounds, backs, & subs. Independent crossover frequencies and slope rates by channel groupings. Stereo subwoofer support with independent level, distance and parametric EQ.
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Post by lesliew on Apr 26, 2017 16:56:53 GMT -5
Not really.. Show a source that is coded for 2 separate lfe channels. Does the XMC-1 count? See my post above
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Post by Mark on Apr 26, 2017 17:12:09 GMT -5
Sorry I missed that reference
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Post by aviolentgrace on Apr 26, 2017 21:14:19 GMT -5
My assertion that it was "odd" was not so much that there is existing content, but that when defining yet another generation of sound formats, they continued to have only a single LFE channel. Much has been made of stereo bass over the years. (For example, read Ken Rockwell's excellent take: kenrockwell.com/audio/stereo-subwoofers.htm ) I can only imagine what a sound system might be like with 3 or 4 distinct LFE tracks (imagine having the possibility of 4 subwoofers in your room, one in each corner, each with its own discrete channel...) So while I won't try to prove the existence of something that doesn't exist (program content with more than one discrete LFE channel), I'm just saying that it's... "odd" that a group of the most forward-looking sound engineers on earth would define 24.1.10 as the 'upper bound' for the home, instead of something like 24.4.10... or heck, even 24.2.10 would have been a start.
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fattykidd
Sensei
It's ok.. I have an et-3.
Posts: 122
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Post by fattykidd on Apr 26, 2017 21:43:40 GMT -5
My assertion that it was "odd" was not so much that there is existing content, but that when defining yet another generation of sound formats, they continued to have only a single LFE channel. Much has been made of stereo bass over the years. (For example, read Ken Rockwell's excellent take: kenrockwell.com/audio/stereo-subwoofers.htm)I can only imagine what a sound system might be like with 3 or 4 distinct LFE tracks (imagine having the possibility of 4 subwoofers in your room, one in each corner, each with its own discrete channel...) So while I won't try to prove the existence of something that doesn't exist (program content with more than one discrete LFE channel), I'm just saying that it's... "odd" that a group of the most forward-looking sound engineers on earth would define 24.1.10 as the 'upper bound' for the home, instead of something like 24.4.10... or heck, even 24.2.10 would have been a start. Yup sure would be great to have discrete mixes with spotty unsmoothed bass throughout the listening area.. Would completely defeat any purpose of multiple subs in immersive sound. I'm a big supporter of stereo subs as an extension for your mains during music playback.. I just can't wrap my head around trying to "place" the low frequencies during movie/film soundtracks. But whatever melts your butter. You're link was showing up broken for me. So I'll try. kenrockwell.com/audio/stereo-subwoofers.htmHe's also, in my unedumacated opinion is talking more about redirected bass.. Not a discrete .1 channel
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Post by aviolentgrace on Apr 26, 2017 22:02:22 GMT -5
I think most of the time the LFE data would be the same on all channels, providing very even response throughout the room. There may be some interesting scenarios in which one might want to have bass predominate from more than one locality, though. For example, consider a sea battle in the golden age of piracy: the percussive rapport cannons firing towards the audience, accompanied by a very excited presentation from the forward (pair of) LFE. Now, emanating from the back of the room comes the crack of the return fire. The treble and midrange tones rip around the surround and height channels, followed by the low, booming report from the rear of the room which the audience *feels* more than *hears*, like a mule gently nudging them from behind with both feet...
The crux is likely the THX-standard 80Hz crossover point. Below that, bass *is* largely un-localized (the brain takes higher frequency cues to add locality), but above that the frequencies are still locatable, yet the physical wavefront is still palpable, if there's enough energy behind it...
Perhaps the beauty of 4 LFE channels would be thus: fore, aft, port, and starboard. If you place subs in the corners of your room, then at any given point in time, you can have the low frequency data from any single cardinal direction be played by a *pair* of subwoofers (giving all the benefits that that brings even (and especially) to monaural LFE) playing the same data. For truly bombastic interplay you can have all 4 go at it at once. And you can have it pan around the room (for those full-frequency 'spinning camera' moments)...
I dunno, I think there's room for 4 data channels with a properly set up room. The beauty of it is that you can always sum them to collapse the data back to a single subwoofer, or smartly sum them to work with dual mono subs.
It's all about choices...
[edit: thanks for the link update -- I fixed my OP as well. looks like the auto-linker is hungry for closing parentheses!)
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KeithL
Administrator
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Post by KeithL on Apr 27, 2017 9:53:51 GMT -5
Everybody is a little bit right here.... but there are some details that most people tend to overlook. First off, yes, bass frequencies below 80 Hz are VERY difficult if not impossible to localize.... and this is especially true in a small room where the bass energy is going to "energize" the entire room. To be honest, I've at least imagined I could hear some localization in a VERY large room, like a theater, with multiple subs. (We're talking about a room 100 x 100 feet - and being able to tell if the sound is coming from "front" or "back".... and I'm not certain what I thought I heard was real.) Second, you need to realize that crossovers are a form of filter - and are not "perfectly sharp" or "brick wall" cutoffs. For example, assuming you set your crossover to 80 Hz, and it's a typical 12 dB/octave crossover, your sub will only be down about -15 dB at 160 Hz, and about -27 dB at 320 Hz. Change that to a 24 dB/octave crossover, and it will still only be down about 27 dB at 160 Hz. In other words, there will still be SOME content going to that sub well above the crossover frequency, and above the frequencies where localization is still somewhat audible. Note that, in a well produced movie soundtrack, the sound engineer was careful to ONLY put sounds in the LFE track that won't be likely to localize; he's going to have made as sure as he can that sounds he's put in the LFE track DON'T include frequencies that will make them easy to localize. When he mixes in the track with that helicopter in it, he's going to put the low frequency thrum of the engine ONLY in the LFE channel, so there's nothing in that channel that will be easy to localize, and he's going to put the higher frequency components of the sound that let you localize it in the appropriate main channels. (You won't have to worry whether your sub is reproducing some of the 160 Hz components that would allow you to localize it - because the engineer didn't put them in that channel to begin with.) Another way to think about it is simply that movie sound tracks are specifically designed to work well with a subwoofer.... so they usually do. In contrast, two channel music is NOT specifically designed to work well with a subwoofer, so it becomes more important that the bass management works well and is set up correctly, and more likely that, even with all that, some localization information will remain that might end up being audible. Finally, there's another aspect of localization that can be significant - extraneous noise. It's VERY difficult to eliminate ALL extraneous noise from a powerful subwoofer. Even the best subwoofers may produce some combination of actual distortion, vibration noise from the driver or the cabinet, port noise (if they're ported), and even the sound of air chuffing through cooling vents in the driver or dust cap. And, even if your subwoofer is dead silent, your room is not. Floors and walls vibrate, pipes in the floor vibrate, and things on shelves nearby vibrate. And many of these tiny noises will serve as powerful localization cues which may interfere with the intended ones. For example, when a real heavy truck drives by your house, you hear bass, and your floor and certain shelves vibrate - and make noise. Even if your subwoofer perfectly reproduces the SOUND of that truck, since the actual source is in a different place, the "incidental cues" may not match perfectly. When you're listening to the sound track, and someone drops a bomb on the roof of the concrete bunker, unless your theater room really is a concrete bunker, there will probably be a few incidental rattles and buzzes that interfere with the perfect illusion of being in a concrete bunker.... and they will prevent your sub from doing a "perfect job". Note that DISCS actually support a single LFE channel (so the folks who produce Blu-Ray discs consider one LFE channel to be sufficient). (Theatrical sound tracks, intended for truly huge rooms, support multiple LFE channels... but home recordings and discs do not.) However, bass management on equipment like the XMC-1, which acts in addition to the track designations on the disc, and works with music as well, supports stereo subwoofers.... I think most of the time the LFE data would be the same on all channels, providing very even response throughout the room. There may be some interesting scenarios in which one might want to have bass predominate from more than one locality, though. For example, consider a sea battle in the golden age of piracy: the percussive rapport cannons firing towards the audience, accompanied by a very excited presentation from the forward (pair of) LFE. Now, emanating from the back of the room comes the crack of the return fire. The treble and midrange tones rip around the surround and height channels, followed by the low, booming report from the rear of the room which the audience *feels* more than *hears*, like a mule gently nudging them from behind with both feet... The crux is likely the THX-standard 80Hz crossover point. Below that, bass *is* largely un-localized (the brain takes higher frequency cues to add locality), but above that the frequencies are still locatable, yet the physical wavefront is still palpable, if there's enough energy behind it... Perhaps the beauty of 4 LFE channels would be thus: fore, aft, port, and starboard. If you place subs in the corners of your room, then at any given point in time, you can have the low frequency data from any single cardinal direction be played by a *pair* of subwoofers (giving all the benefits that that brings even (and especially) to monaural LFE) playing the same data. For truly bombastic interplay you can have all 4 go at it at once. And you can have it pan around the room (for those full-frequency 'spinning camera' moments)... I dunno, I think there's room for 4 data channels with a properly set up room. The beauty of it is that you can always sum them to collapse the data back to a single subwoofer, or smartly sum them to work with dual mono subs. It's all about choices... [edit: thanks for the link update -- I fixed my OP as well. looks like the auto-linker is hungry for closing parentheses!)
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Post by FilmMixer on May 8, 2017 21:04:16 GMT -5
Everybody is a little bit right here.... but there are some details that most people tend to overlook. First off, yes, bass frequencies below 80 Hz are VERY difficult if not impossible to localize.... and this is especially true in a small room where the bass energy is going to "energize" the entire room. To be honest, I've at least imagined I could hear some localization in a VERY large room, like a theater, with multiple subs. (We're talking about a room 100 x 100 feet - and being able to tell if the sound is coming from "front" or "back".... and I'm not certain what I thought I heard was real.) Second, you need to realize that crossovers are a form of filter - and are not "perfectly sharp" or "brick wall" cutoffs. For example, assuming you set your crossover to 80 Hz, and it's a typical 12 dB/octave crossover, your sub will only be down about -15 dB at 160 Hz, and about -27 dB at 320 Hz. Change that to a 24 dB/octave crossover, and it will still only be down about 27 dB at 160 Hz. In other words, there will still be SOME content going to that sub well above the crossover frequency, and above the frequencies where localization is still somewhat audible. Note that, in a well produced movie soundtrack, the sound engineer was careful to ONLY put sounds in the LFE track that won't be likely to localize; he's going to have made as sure as he can that sounds he's put in the LFE track DON'T include frequencies that will make them easy to localize. When he mixes in the track with that helicopter in it, he's going to put the low frequency thrum of the engine ONLY in the LFE channel, so there's nothing in that channel that will be easy to localize, and he's going to put the higher frequency components of the sound that let you localize it in the appropriate main channels. (You won't have to worry whether your sub is reproducing some of the 160 Hz components that would allow you to localize it - because the engineer didn't put them in that channel to begin with.) Another way to think about it is simply that movie sound tracks are specifically designed to work well with a subwoofer.... so they usually do. In contrast, two channel music is NOT specifically designed to work well with a subwoofer, so it becomes more important that the bass management works well and is set up correctly, and more likely that, even with all that, some localization information will remain that might end up being audible. Finally, there's another aspect of localization that can be significant - extraneous noise. It's VERY difficult to eliminate ALL extraneous noise from a powerful subwoofer. Even the best subwoofers may produce some combination of actual distortion, vibration noise from the driver or the cabinet, port noise (if they're ported), and even the sound of air chuffing through cooling vents in the driver or dust cap. And, even if your subwoofer is dead silent, your room is not. Floors and walls vibrate, pipes in the floor vibrate, and things on shelves nearby vibrate. And many of these tiny noises will serve as powerful localization cues which may interfere with the intended ones. For example, when a real heavy truck drives by your house, you hear bass, and your floor and certain shelves vibrate - and make noise. Even if your subwoofer perfectly reproduces the SOUND of that truck, since the actual source is in a different place, the "incidental cues" may not match perfectly. When you're listening to the sound track, and someone drops a bomb on the roof of the concrete bunker, unless your theater room really is a concrete bunker, there will probably be a few incidental rattles and buzzes that interfere with the perfect illusion of being in a concrete bunker.... and they will prevent your sub from doing a "perfect job". Note that DISCS actually support a single LFE channel (so the folks who produce Blu-Ray discs consider one LFE channel to be sufficient). (Theatrical sound tracks, intended for truly huge rooms, support multiple LFE channels... but home recordings and discs do not.)However, bass management on equipment like the XMC-1, which acts in addition to the track designations on the disc, and works with music as well, supports stereo subwoofers.... You are incorrect. There is no theatrical sound format that supports more than one LFE channel.
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Post by aviolentgrace on May 9, 2017 11:58:32 GMT -5
There is no theatrical sound format that supports more than one LFE channel. Now that is truly fascinating! You'd figure in the "land of no limits" they (they being THX* and/or Dolby and/or dts) would have added one if they felt it was beneficial. So the conclusions from all of this are: - Discrete LFE doesn't exist for cinematic mixes, either now or for the foreseeable future.
- Extra subwoofers are only useful for:
* Taming a room (evening out its response / eliminating peaks and nulls) * Blowing out car windows at car audio SPL competitions * Accurately representing lower-register information in a stereo music mix
(* I know THX is not a sound encoding, it's a set of standards to normalize (and maximize) theater performance... but if THX put out guidance that said "All THX Super Platinum Certified theaters must support 6 discrete LFE channels with these parameters..." you can bet that Dolby and dts would hop-to and work out the encoding required to deliver it.)
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Post by jmilton on May 9, 2017 12:32:01 GMT -5
Isn't the LFE mono anyways? Why would you need more discrete channels? The basic point here is that the LFE channel is not the "subwoofer channel"
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Post by monkumonku on May 9, 2017 12:51:17 GMT -5
Isn't the LFE mono anyways? Why would you need more discrete channels? To make sure that the left mono is balanced with the right mono?
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Post by jmilton on May 9, 2017 12:52:30 GMT -5
...and if it were, you'd have a "phantom" mono center.
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KeithL
Administrator
Posts: 9,960
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Post by KeithL on May 9, 2017 13:57:52 GMT -5
There are a few nuances you need to keep in mind..... The LFE channel was always intended for LOW FREQUENCY EFFECTS.... as in "sound effects". It was intended specifically for special effects noises, and specifically for sounds that would not be easy to localize. Therefore, there shouldn't be anything in the LFE channel that would be easy to localize. However, the subwoofer (or subwoofers) in your home system carry both content from the LFE channel and the parts of the content from all your other channels that are routed to it by your bass management system (the frequency range below each channel's crossover - if it's set to "small"). This content may in fact still contain some frequency components that allow it to be somewhat localized. For example, the filters used in your bass management system actually have a somewhat gradual cutoff. If you have your crossovers set to 80 Hz, sounds at 160 Hz will be down -15 dB with a 12 dB/octave setting, and sounds at 160 Hz will be down about -27 dB with a 24 dB/octave setting. This means that some small fraction of sounds well above that 80 Hz crossover point will make it through. (This wouldn't matter with the LFE channel, because there shouldn't BE anything there at those frequencies, but your other channels are full range.) It's also been suggested that, in some circumstances - especially with very large rooms and certain types of speakers - some small amount of localization may still exist down to or below 80 Hz. So, again, while it shouldn't matter for LFE content, there might be some audible difference between stereo and mono subs for systems that use bass management. We might also expect this to be more likely if you use 12 dB/octave filters rather than 24 dB/octave ones for your bass management crossovers. (I would agree that the difference isn't usually audible, but I wouldn't rule out the possibility that it sometimes might be.) There is no theatrical sound format that supports more than one LFE channel. Now that is truly fascinating! You'd figure in the "land of no limits" they (they being THX* and/or Dolby and/or dts) would have added one if they felt it was beneficial. So the conclusions from all of this are: - Discrete LFE doesn't exist for cinematic mixes, either now or for the foreseeable future.
- Extra subwoofers are only useful for:
* Taming a room (evening out its response / eliminating peaks and nulls) * Blowing out car windows at car audio SPL competitions * Accurately representing lower-register information in a stereo music mix
(* I know THX is not a sound encoding, it's a set of standards to normalize (and maximize) theater performance... but if THX put out guidance that said "All THX Super Platinum Certified theaters must support 6 discrete LFE channels with these parameters..." you can bet that Dolby and dts would hop-to and work out the encoding required to deliver it.)
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DYohn
Emo VIPs
Posts: 18,353
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Post by DYohn on May 9, 2017 14:12:06 GMT -5
There are a few nuances you need to keep in mind.....edit Well said Keith. IIRC from my days at THX, the LFE channel crossover should be set to 120Hz.
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Post by goozoo on May 9, 2017 16:01:44 GMT -5
Does anyone know or think that Emo will offer a buyback program for current XMC-1 gen 1 owners like they have in the past when the RMC-1 is available for order? Any guesses as to how much it would be? I seem to recall an email about the trade in program where they mentioned a buyback of $1250 for the processor.
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