[Davesrose]

Actually you have that backwards. The masters were compressed for *some* early CDs(hence all the DR12 values I'm getting on the MAAT DR meter), but I believe the guy I quoted(Davesrose) was referring to the later 'remaster' editions(late 1990s reissues of Thriller for example) which were compressed and limited for loudness.

Wait, you seem to have things backwards. You quote me (Davesrose), then say you were quoting another guy named Davesrose. All my (Davesrose) posts have been referencing early CD releases.

 

[TheSonicTruth]

Sorry, but CDs aren't all mastered the same. I also work with computers and know what data compression is: I obviously wasn't referring to compression as that. My use of the word was referring to audio, but probably wasn't the best word (as I didn't mean dynamic range but reducing frequency range around tape hiss). Since my post did reference tape hiss, I'm not sure how you got to data compression.

I'll probably catch flack for this(or FLAC! ), but I refer to the two forms as 'dynamic compression' and 'data REDUCTION'. No confusion there!

 

[TheSonicTruth]

Wait, you seem to have things backwards. You quote me (Davesrose), then say you were quoting another guy named Davesrose. All my (Davesrose) posts have been referencing early CD releases.

Go back to post #10249 or thereabouts: Did someone else named 'Davesrose' type that?

 

[Davesrose]

Go back to post #10249 or thereabouts: Did someone else named 'Davesrose' type that?

No, I typed that one and I only refer to early CDs then. At no time did I, Davesrose, talk about mastering CDs from the 90s. It appears you quoted the first post I made about observations of CD and high-res formats still being debated on this forum. And at no point does any post from Davesrose disagree with you. From what I can see going back to the previous page, you were having a back and forth with analogsurvivor

 

[dprimary]

Indeed...that's one immediate thing I found with demoing vinyl vs CD masterings of the 80s. Many early CDs were audibly compressed to eliminate any tape hiss and just sound awful now. Digital processing has greatly improved so that dynamics sound great in within CD standards.

Compression will increase tape hiss since you are decreasing the dynamic range. Many early transfer transfers sound bad because master tape sounded really bad to start with. Luckily many of the drugs consumed at the time drastically reduced high frequency hearing so the final mixes are screaming bright. So the mastering engineer reduces the high frequencies back to normal the hiss gets reduced. Drug induced noise reduction.
When the record companies rushed to reissue thousands upon thousands of reissues they did straight transfers it was not mastered like the original vinyl had been. Back then You recorded and mixed to compensate for the many short comings of vinyl since it was mixed for a lossy format you can never get it back if all you have left is the half track master. If it was remixed from the multitrack you have more options however it will sound vastly different. The chances of you getting every fader move and effect exact is close to zero. Some remixed releases are not even the same take. The performance is not the same one as the original. How reviewers and audiophiles miss that is mystery to me.

 

[castleofargh]

Wait, you seem to have things backwards. You quote me (Davesrose), then say you were quoting another guy named Davesrose. All my (Davesrose) posts have been referencing early CD releases.

 

[bfreedma]

If I had the editing tools and skill, I’d update that video and replace every verbal and written “Malkovich” with “compression”.

 

[gregorio]

[1] Every source I've seen about surround sound has said one shouldn't confuse LFE with a subwoofer channel. [2] In regards to DB, as my linked article went over, all other tracks are targeted at 85DB, while LFE channels are targeted at 95DB.

1. There isn't such a thing as a "subwoofer channel" per se. I think you have misunderstood, what "every source" is warning you about is not to confuse the LFE channel with the subwoofer information generated by a bass management system.
2. I'm not sure which of your linked articles you're referencing but either it's wrong or you have misunderstood it! The main screen channels are referenced to 85dBSPL (= -20dBFS) but the LFE channels are NOT targeted at 95dBSPL. The LFE channel/subwoofer has +10dB of in-band gain applied relative to the screen channels. If one were to (incorrectly) measure full-band, that would typically result in the calibration of the sub being somewhere around 91dB relative to the 85dB of the screen speakers, not 95dB.

https://www.google.com/url?sa=t&rct...8-p180006221&usg=AOvVaw2Q3QbXkT-3X6Jo9qs5GMMW
" Object-based format is the most original format of a sound recording. Object-based format represents a sound scene using a combination of sound objects with the associated metadata [HHK15]. Sound objects are essentially individual sound sources. ... The greatest benefit of object-based audio is that it can be rendered optimally for any arbitrary playback systems. Meanwhile, interactivity can be enabled, for example, changing to another language of speech, increasing the loudness of certain objects (e.g., speech level shall be higher for hearing-impaired listeners), and adapting the position of the sound objects according to listener’s movement in virtual reality applications. The object-based format is the best format in terms of reproduction flexibility and quality.

Kudos for actually presenting some scientific documentation but not quite so much kudos for not reading it all and not really understanding it's context. In effect, the extract presents the current state of research and the areas requiring more research, in order to develop the theory further and ultimately lead to solution which is applicable in practise. In a sense it's a bit like an extract on teleportation, sure there are many advantages of teleportation over catching a plane but there's one big obvious disadvantage, teleportation isn't actually possible yet! The serious articles on teleportation are presenting theories on how it might work in the future and the article you linked to is of a similar type. This isn't an ideal analogy because the theories presented on audio objects can actually be implemented and be made to work but only under very specific conditions and only at a very simplistic level. Conditions which could be practically applied to about 1% of music production and about 0% of film/TV production (and nowhere close to the level of complexity required)! The extract itself states: "Despite the recent advances in BSS and PAE, the challenges due to the complexity and uncertainty of the sound scenes still remain to be resolved". The cutting edge of what's currently commercially available in separating sounds is autonomously effective about 15% of the time and even then, only with certain types of fairly simple examples, it's a similar story with reverb extraction, both of which employ fairly sophisticated machine learning. Recreating reverb/spacial information is also relatively rudimentary. I can't see how a full practical solution could ever be possible but assuming I'm wrong, we're looking at decades rather than years in the future and certainly not something that's possible today.

G

 

[Davesrose]

1. There isn't such a thing as a "subwoofer channel" per se. I think you have misunderstood, what "every source" is warning you about is not to confuse the LFE channel with the subwoofer information generated by a bass management system.
2. I'm not sure which of your linked articles you're referencing but either it's wrong or you have misunderstood it! The main screen channels are referenced to 85dBSPL (= -20dBFS) but the LFE channels are NOT targeted at 95dBSPL. The LFE channel/subwoofer has +10dB of in-band gain applied relative to the screen channels. If one were to (incorrectly) measure full-band, that would typically result in the calibration of the sub being somewhere around 91dB relative to the 85dB of the screen speakers, not 95dB

In case you did want to check the source, I'll post it again:
https://hometheaterhifi.com/editorial/the-misunderstood-01-lfe-channel-in-51-digital-surround-sound/

"During both soundtrack production and in the movie theaters, the LFE channel, with that same level (-20dB) pink noise (but band limited to the subwoofers range), is calibrated to 95 dB on the RTA within the sub’s bandwidth (Figures 2 and 3). This is done so that it can play 10 dB higher than any one of the screen channels. Because of this 10 dB offset, the LFE channel can achieve a balanced output of bass as compared with the total output of bass from the three screen channels (in other words it can single handedly compete with the screen channels in terms of level). The only down side is that we lose a little S/N (signal to noise) performance on that track. Because our hearing is less sensitive to bass to begin with, the system gets away with it just fine."

When it comes to the difference between 85DB vs LFE 95DB: the article says it's in the playback level.

Kudos for actually presenting some scientific documentation but not quite so much kudos for not reading it all and not really understanding it's context. In effect, the extract presents the current state of research and the areas requiring more research, in order to develop the theory further and ultimately lead to solution which is applicable in practise.

I don't believe I showed ignorance. I did say that I realize Atmos is not a pure object-based system. As to when object-based systems will be fully utilized: technologies mature at an exponential rate. No one could have realized how quickly facial recognition matured (due to advances in neural networking).

 

[gregorio]

[1] Thanks for the compliment on the FR response and the additional information. I'll either dig up an existing waterfall or take a new one once work eases up. I will readily admit that it's not as purty as the FR - the room in question is a mixed use room so to keep some level of harmony (considering the investment in speakers and measurement gear), typical room treatments aren't an option.
2a. No disagreement in principle, but as someone who can reproduce sub 30Hz content with a modicum of accuracy, I wish it wasn't being truncated. I do realize that the industry has to cater to the majority, so I'll just sulk in the corner quietly on that one going forward
3. From the FR and spectrum plots I've seen for a few movies, I do think there are a few that have intentional content below 20Hz but will defer to your industry knowledge and not argue that most of the sub 20Hz content is unintended residue or unedited channels.
[4] I'll also own up to the fact that watching a blockbuster movie and reproducing ULF is a pleasant experience for me, so even if it's unintended content, it rarely feels out of context with what is occurring on screen. Please don't ruin my fun

1. I wouldn't expect it to be as "purty" as the FR plot. You can usually somewhat "fix" many FR probs with EQ, to get a fairly decent plot but that's a two edged sword because some of those FR plot probs are related to time/duration of resonance rather than just peak levels, so although you might get a "purty" FR plot with EQ, you may have achieved it by reducing the EQ'ed freqs well below flat. The only way to deal with this is with acoustic treatment but if that's not possible/practical, it's almost always preferable to sacrifice some of the "purtiness" of your FR plot. I completely appreciate you've done the best with what was practical/possible and IMHO that's all we can reasonably ask.

2a. I would guess that far less than 1% of consumers can even reproduce 30Hz with any accuracy, let alone below 20Hz. However, I will adjust material down as far as I can detect or reproduce (which is 19Hz), "just in case" but in all the cases I can recall where I've done so, it was always because of some headroom usage rather than any material audio quality concern.

3. I can't say for absolute certain. I've not seen/heard all movies and while I've worked in some world class dub stages I've certainly not worked in them all. The top dub stages have custom built systems and it's possible some go lower than the norm (of other world class facilities). Professional practice/guidance has always been; "don't deliberately put anything in there below 25Hz". There may of course be someone who deliberately ignored the professional practice and therefore there might be some examples of intentional content below 20Hz but I've never done it, I've never seen or even heard of anyone else doing it and I can't see any reason why anyone would.

4. As a mixer, I (and my colleagues) am slightly disturbed by the idea of you reproducing down to 14Hz, from the point of view that I'm uncomfortable with you reproducing material that I haven't heard/vetted. Although having said this: 1. Anything down there should hopefully be innocuous and 2. It's becoming somewhat of an unfortunate fact of life that we can't just go on what our ears/perception/judgment are telling us any more. More so with higher sample rate music than film, we're having to guess what's there from looking at spectograms because we can't actually hear more than half the freq spectrum of what goes out our doors! As a type of commercial artist who earns a living from it, I have to accept that once it's out of my doors, it's no longer "mine". The consumer buys it and it's up to them how they choose to reproduce/hear it and to be honest I don't really have a problem with that. If someone wants tube distortion all over their reproduction, that's fine, they've paid to reproduce it how they want and I'm making a living doing what I love because they were willing to pay for it. The only time I have a problem is when they try to convince me or others that reproducing it how they want (with say tube distortion) is somehow higher fidelity/more accurate. You're not trying to convince me or others that you're getting better fidelity, just that you enjoy listening to it that way, which is fine and to be honest, I often have my home sub a little higher than I know it should be because purely for my own pleasure, I like bass!

G

 

[gregorio]

[1] I don't believe I showed ignorance.
[2] As to when object-based systems will be fully utilized: technologies mature at an exponential rate.

1. And yet you're misunderstanding LFE/subwoofer calibration. You seem to be misunderstanding the "in-band" part. If you take a full range screen speaker outputting 85dBSPL and remove everything above 120Hz, then it will no longer be outputting 85dB, it will be outputting more like 81dB. If you then calibrate the LFE/subwoofer to be 10dB higher, that would be 91dB, not 95dB. Here's how Dolby themselves describe calibrating the LFE/subwoofer:

"Ideally, the test noise used for subwoofer calibration should be band-limited pink noise, low-pass filtered at 120 Hz. To properly calibrate the subwoofer, an RTA is required... When using an RTA, proper calibration requires setting the LFE channel signal sent to the subwoofer, within its typical bandwidth of 25 to 120 Hz, 10 dB higher than the main channels.If an RTA is not available, setting the LFE channel higher (e.g., ~ 90 to 91 dBc for the subwoofer channel when the Center channel measures 85 dBc), can give an approximate level with an SPL meter."

2. Are we exponentially closer to a teleportation device? Technologies typically mature at an exponential rate only from the point at which they exist. The technology doesn't currently exist to deal with the type of complex signals that modern music and film/TV production are. The extract YOU cited specifically states that!

G

 

[Davesrose]

1. And yet you're misunderstanding LFE/subwoofer calibration. You seem to be misunderstanding the "in-band" part. If you take a full range screen speaker outputting 85dBSPL and remove everything above 120Hz, then it will no longer be outputting 85dB, it will be outputting more like 81dB. If you then calibrate the LFE/subwoofer to be 10dB higher, that would be 91dB, not 95dB. Here's how Dolby themselves describe calibrating the LFE/subwoofer:

And now you're showing you take things out of context: when that sentence was in reference to the paper on object-based models. You've accused me of not understanding my sources, when you didn't read them initially. You asked if I understood the article on LFE I previously posted. It specifically says RTA of 85DB and 95DB. If you dispute that, then that's with the author of the article and not me. I wonder also if there's a difference in authoring between cinema and home applications.

2. Are we exponentially closer to a teleportation device? Technologies typically mature at an exponential rate only from the point at which they exist. The technology doesn't currently exist to deal with the type of complex signals that modern music and film/TV production are. The extract YOU cited specifically states that!

I don't know why you're fixated in unicorns and teleportation. We were talking about guessing when full implementation of object-based audio comes about, which has a basis in current object-based models. The paper I cited listed issues at hand: it doesn't say we're doomed to never have these models.

 

[bfreedma]

1. I wouldn't expect it to be as "purty" as the FR plot. You can usually somewhat "fix" many FR probs with EQ, to get a fairly decent plot but that's a two edged sword because some of those FR plot probs are related to time/duration of resonance rather than just peak levels, so although you might get a "purty" FR plot with EQ, you may have achieved it by reducing the EQ'ed freqs well below flat. The only way to deal with this is with acoustic treatment but if that's not possible/practical, it's almost always preferable to sacrifice some of the "purtiness" of your FR plot. I completely appreciate you've done the best with what was practical/possible and IMHO that's all we can reasonably ask.

2a. I would guess that far less than 1% of consumers can even reproduce 30Hz with any accuracy, let alone below 20Hz. However, I will adjust material down as far as I can detect or reproduce (which is 19Hz), "just in case" but in all the cases I can recall where I've done so, it was always because of some headroom usage rather than any material audio quality concern.

3. I can't say for absolute certain. I've not seen/heard all movies and while I've worked in some world class dub stages I've certainly not worked in them all. The top dub stages have custom built systems and it's possible some go lower than the norm (of other world class facilities). Professional practice/guidance has always been; "don't deliberately put anything in there below 25Hz". There may of course be someone who deliberately ignored the professional practice and therefore there might be some examples of intentional content below 20Hz but I've never done it, I've never seen or even heard of anyone else doing it and I can't see any reason why anyone would.

4. As a mixer, I (and my colleagues) am slightly disturbed by the idea of you reproducing down to 14Hz, from the point of view that I'm uncomfortable with you reproducing material that I haven't heard/vetted. Although having said this: 1. Anything down there should hopefully be innocuous and 2. It's becoming somewhat of an unfortunate fact of life that we can't just go on what our ears/perception/judgment are telling us any more. More so with higher sample rate music than film, we're having to guess what's there from looking at spectograms because we can't actually hear more than half the freq spectrum of what goes out our doors! As a type of commercial artist who earns a living from it, I have to accept that once it's out of my doors, it's no longer "mine". The consumer buys it and it's up to them how they choose to reproduce/hear it and to be honest I don't really have a problem with that. If someone wants tube distortion all over their reproduction, that's fine, they've paid to reproduce it how they want and I'm making a living doing what I love because they were willing to pay for it. The only time I have a problem is when they try to convince me or others that reproducing it how they want (with say tube distortion) is somehow higher fidelity/more accurate. You're not trying to convince me or others that you're getting better fidelity, just that you enjoy listening to it that way, which is fine and to be honest, I often have my home sub a little higher than I know it should be because purely for my own pleasure, I like bass!

G

Again, thanks for the detailed response. It’s interesting getting and understanding the view from the content creation side!

1. Since significant physical room acoustic treatment isn’t an option for me, my next AVR purchase will include Dirac as it purports to be able to work in time domain as well as frequency response. Audyssey is essentially FR only. I will post a waterfall as soon as I can retake the measurements as I’d very much like your opinion on whether the EQ is doing more damage via excessive resonance than I’m getting back in value with the relatively flat FR.

2a. Completely sensible. As much as I want to leverage my investment in low frequency response, I fully appreciate the need to create content that works best for the vast majority and not outlying use cases. I just hope that the trend away from full size 5.1 or more channels to sound bars doesn’t force the content creators and mixers to further reduce LF content. I’m continually disappointed at how many people invest big $ in large screens or projectors then stick a $200 sound bar under it. Not my idea of a theater experience.

3, Again, I’ll certainly defer to your domain knowledge and expertise, but I do think there are a few cases where the “rules” have been broken. The best example that comes to mind is the server room scene in Pulse. There is some content from 6Hz - 18Hz that seems to be too well aligned with the scene and the intent to cause the type of physical reaction ULF generates in humans to be purely accidental. It could be residue from other LF between 20Hz-40Hz but if so, it’s certainly an unusually successful coincidence.

4. I bought it, so it’s mine, mine, all mine (evoking Donald Duck). More seriously, I do understand the frustration of losing control of content and the potential for it to be misused once it’s out of your hands. A good deal of my work involves developing strategic IT roadmaps for large organizations. All too often, when I come back a year or two later to extend it, I wonder what the consumers of the roadmap were thinking when I see how far off the map they have gone and how poorly aligned to business requirements the changes are. Not exactly the same as what you live with, but similar frustration seeing what I believe to be a well thought out strategy devolve into something unintended. As you suggest, not much I can do about it once it’s out of my hands. More specifically to ULF reproduction, I do think it’s fairly innocuous as it doesn’t (for me) do much more than add some tactile element to the existing audible content. Frankly, it’s also a fairly rare occurrence- my finger in the wind estimate is that it’s only being generated in my system in 10% of the films watched and in those films, less than 1% of the running time. It’s more important to me that my subwoofers are highly capable between 40Hz - 80Hz. Content below that is just a nice bonus.

 

[TheSonicTruth]

1. And yet you're misunderstanding LFE/subwoofer calibration. You seem to be misunderstanding the "in-band" part. If you take a full range screen speaker outputting 85dBSPL and remove everything above 120Hz, then it will no longer be outputting 85dB, it will be outputting more like 81dB. If you then calibrate the LFE/subwoofer to be 10dB higher, that would be 91dB, not 95dB. Here's how Dolby themselves describe calibrating the LFE/subwoofer:

"Ideally, the test noise used for subwoofer calibration should be band-limited pink noise, low-pass filtered at 120 Hz. To properly calibrate the subwoofer, an RTA is required... When using an RTA, proper calibration requires setting the LFE channel signal sent to the subwoofer, within its typical bandwidth of 25 to 120 Hz, 10 dB higher than the main channels.If an RTA is not available, setting the LFE channel higher (e.g., ~ 90 to 91 dBc for the subwoofer channel when the Center channel measures 85 dBc), can give an approximate level with an SPL meter."

2. Are we exponentially closer to a teleportation device? Technologies typically mature at an exponential rate only from the point at which they exist. The technology doesn't currently exist to deal with the type of complex signals that modern music and film/TV production are. The extract YOU cited specifically states that!

G

"The technology doesn't currently exist to deal with
the type of complex signals that modern music and
film/TV production are. The extract YOU cited specifically
states that!"

I read the article he linked to forwards and backwards, and did not read anything stating such, implicitly or indirectly. My equipment does a perfectly fine job dealing with "the type of complex signals that modern music and film/TV production" are capable of generating.

 

[TheSonicTruth]

And now you're showing you take things out of context: when that sentence was in reference to the paper on object-based models. You've accused me of not understanding my sources, when you didn't read them initially. You asked if I understood the article on LFE I previously posted. It specifically says RTA of 85DB and 95DB. If you dispute that, then that's with the author of the article and not me. I wonder also if there's a difference in authoring between cinema and home applications.



I don't know why you're fixated in unicorns and teleportation. We were talking about guessing when full implementation of object-based audio comes about, which has a basis in current object-based models. The paper I cited listed issues at hand: it doesn't say we're doomed to never have these models.

Ohhh Gregorio excels at doing those things! Don't take it too personally. I've learned to develop a thick skin when dealing with those for whom the world is wrong and they're right.