[Davesrose]

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.

Agreed. I haven't really demoed a sound bar, but it is funny how much attention they're getting. They must have EQ parameters to try compensating for lack of range (which isn't new: IE Bose 901 EQ module). A friend of mine said he was really blown away with hearing a Sonos. I quipped if it could be anywhere approaching my full range sound system. He said no, but it was good for what it was...size being the main factor. But I do roll my eyes at expensive brands like Bose. Their Lifestyle series has a center console that doesn't handle the latest surround formats, and their kit is more expensive than getting a full receiver with Klipsch speaker kit.

 

[gregorio]

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.

The author isn't wrong, you're understanding of what he wrote is wrong! Admittedly what he wrote was maybe a little confusing but you're ignoring the "RTA" part of that statement. The RTA part refers to a Real Time Analyser reading the in-band levels (IE. 20Hz - 120Hz). Again, if you have a screen speaker outputting 85dB and then remove everything above 120Hz, it will only be outputting about 81dB. You can then increase the output level of that screen speaker so it's outputting 85dB in-band and then set the LFE/sub output to be 95dB (+10dB). If you measure the output of that screen speaker without the RTA only reading the 20-120Hz band, it would read something around 89dB rather than the required 85dB calibration level. Are you disputing the information from Dolby themselves who actually invented 5.1?

We were talking about guessing when full implementation of object-based audio comes about, which has a basis in current object-based models.

That might be what you're talking about but it not what I or the article are talking about. I'll remind you of the statement: "... the challenges due to the complexity and uncertainty of the sound scenes still remain to be resolved". There's been a great incentive to "resolve" these issues for 30 years or more and yet they "still remain to be resolved", they are currently unresolvable! Once it is resolved, if in fact it ever can be, then probably technology will progress exponentially but until then there cannot be a "full implementation". The problem is not just one of better technology for the current object-based models, it's a problem that the current object-based models simply cannot cope with real world commercial audio, regardless of how much technology you throw at those current models. What is required is different, massively more sophisticated models!

G

 

[bfreedma]

Agreed. I haven't really demoed a sound bar, but it is funny how much attention they're getting. They must have EQ parameters to try compensating for lack of range (which isn't new: IE Bose 901 EQ module). A friend of mine said he was really blown away with hearing a Sonos. I quipped if it could be anywhere approaching my full range sound system. He said no, but it was good for what it was...size being the main factor. But I do roll my eyes at expensive brands like Bose. Their Lifestyle series has a center console that doesn't handle the latest surround formats, and their kit is more expensive than getting a full receiver with Klipsch speaker kit.

Bose has certainly been successful at marketing generally poor to ridiculously bad speakers and electronics. Let’s not even discuss Bose “subs”, which barely qualify as mid bass modules. Their profit margin allows them to advertise incessantly and the cycle continues. As you state, you can do a lot better for far less money. I will say that the QC35 headphone is an exception - not a bad deal for travel headphones with ANC.

I’m not entirely anti sound bar. I use one for our bedroom TV where a surround system is both impractical and really not necessary as we use the home theater when watching movies. The relatively inexpensive Zvox is far better than the TV’s built in speakers, particularly for improving voice intelligibility.

 

[Davesrose]

The author isn't wrong, you're understanding of what he wrote is wrong! Admittedly what he wrote was maybe a little confusing but you're ignoring the "RTA" part of that statement. The RTA part refers to a Real Time Analyser reading the in-band levels (IE. 20Hz - 120Hz). Again, if you have a screen speaker outputting 85dB and then remove everything above 120Hz, it will only be outputting about 81dB. You can then increase the output level of that screen speaker so it's outputting 85dB in-band and then set the LFE/sub output to be 95dB (+10dB). If you measure the output of that screen speaker without the RTA only reading the 20-120Hz band, it would read something around 89dB rather than the required 85dB calibration level. Are you disputing the information from Dolby themselves who actually invented 5.1?

I am done talking with you when you show you continue to want to switch topics. The author and Dolby refer to RTA...and you keep wanting to expand on the DB without RTA.

 

[gregorio]

I've learned to develop a thick skin when dealing with those for whom the world is wrong and they're right.

Unfortunately, you've developed a skin so thick that you've invented your own world! The conversation I'm involved in is the calibration of LFE channel in film, which I was taught by the head technician of Dolby (Europe) and as Dolby effectively had a worldwide monopoly on 5.1 sound on 35mm film, as they invented it, then that is the "world".And, as I've directly quoted the information published by Dolby, what world is it you live in that disagrees with it?

G

 

[gregorio]

The author and Dolby refer to RTA...and you keep wanting to expand on the DB without RTA.

What do you mean I keep wanting to expand on the dB without RTA? Dolby specifies the 85dB calibration of the screen (front) speakers WITHOUT RTA, not me! And that 85dB calibration level without RTA is what you quoted!

G

 

[Davesrose]

What do you mean I keep wanting to expand on the dB without RTA? Dolby specifies the 85dB calibration of the screen (front) speakers WITHOUT RTA, not me! And that 85dB calibration level without RTA is what you quoted!

G

Once again from post 10269-

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."

 

[Jaywalk3r]

Statistical methods can't fix flawed experimental methods.

Agreed. But not understanding the underlying logic of the methods is not the same as those methods being flawed.

You're either being disingenuous or you're not so bright.

Neither description is accurate. His description highlighted a worry of random effects unduly affecting the decision. We address that by decreasing alpha and/or increasing sample size.

Rarely would we focus on beta specifically, lest we risk increasing alpha to an unacceptable level. If we are worried of insufficient power of the test, we increase the sample size.

Here, we would also not be much concerned with beta, compared to alpha. The differences are claimed to be clearly audible.

This is complete nonsense, and you must know it.

Again, no.

It's simple logic. If the subject can't hear it, it isn't audible, by definition of audible.

 

[gregorio]

Once again from post 10269- 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."

And still you are ignoring the "RTA" part??! The sub is calibrated to 95dB which is 10dB more than a screen speaker outputting about 89dB (which will read 85dB on the band-limited the RTA). However, the screen speakers should be calibrated to 85dBSPLC without an RTA not 89dB, so the system level needs to be reduced by about 4dB (keeping the same relationship between the sub and screen speaker) and of course then the sub will be outputting about 91dB, not 95dB. Again this is Dolby's own words "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.". I don't know how to make this any clearer, the centre (and other screen channels) are calibrated to 85dBC with an SPL meter, NOT a band-limited RTA, with a band-limited RTA those screen speakers would only read about 81dB.

Furthermore, the 85dBSPLC = -20dBFS is the screen speaker calibration for cinemas ONLY. For home cinemas the calibration level of each screen speaker relative to -20dBFS should be about 79dBSPLC, not 85.

G

 

[Joe Bloggs]

And still you are ignoring the "RTA" part??! The sub is calibrated to 95dB which is 10dB more than a screen speaker outputting about 89dB (which will read 85dB on the band-limited the RTA). However, the screen speakers should be calibrated to 85dBSPLC without an RTA not 89dB, so the system level needs to be reduced by about 4dB (keeping the same relationship between the sub and screen speaker) and of course then the sub will be outputting about 91dB, not 95dB. Again this is Dolby's own words "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.". I don't know how to make this any clearer, the centre (and other screen channels) are calibrated to 85dBC with an SPL meter, NOT a band-limited RTA, with a band-limited RTA those screen speakers would only read about 81dB.

Furthermore, the 85dBSPLC = -20dBFS is the screen speaker calibration for cinemas ONLY. For home cinemas the calibration level of each screen speaker relative to -20dBFS should be about 79dBSPLC, not 85.

G

Why would you avoid the RTA like poison when the RTA is clearly the more accurate tool? How can one give exact figures for what the broadband response of each speaker should be without complete knowledge of both the program material and the FR curves of the speakers?

 

[Joe Bloggs]

What I WOULD be interested in knowing is, supposing all speakers give flat in-band response, what should the single-tone response level be for the LFE relative to the other channels given the same digital input level? Should it be 10dB higher? 5? ??

This is a much more relevant question to me because I mix down the sub with centre and recalculate sub output by crossing over my specified LF part of all channels to the sub. So the answer to the above is the number by which I should be amplifying the LFE channel before mixing it into the centre channel, correct? Does this apply to multichannel music as well?

 

[TheSonicTruth]

Why would you avoid the RTA like poison when the RTA is clearly the more accurate tool? How can one give exact figures for what the broadband response of each speaker should be without complete knowledge of both the program material and the FR curves of the speakers?

Why? Because he's 'gregorio', that's why.

 

[gregorio]

Why would you avoid the RTA like poison when the RTA is clearly the more accurate tool? How can one give exact figures for what the broadband response of each speaker should be without complete knowledge of both the program material and the FR curves of the speakers?

The calibration procedure is to use an RTA on the screen speakers and ensure the speaker's FR corresponds to the "x-curve". Once the FR is set, each of the screen speakers is then level calibrated to 85dB SPL "C" with an SPL meter, referenced against -20dBFS pink noise. The RTA is then used to ensure the FR of the sub array and then it's is level calibrated. This is done by setting (say) the centre speaker to output 85dBSPL within the 20-120Hz band (which you determine by use of an RTA measuring just that band), then set the sub array to +10dB higher (than the band-limited measurement of the centre speaker). To achieve that 85dB band-limited measurement from the centre speaker it has to be outputting something like 89dBSPL (non-band limited) but of course the calibration level should actually be 85dBSPL (C), not 89dB, so you have to turn your centre speaker down by about 4dB (and your sub which is referenced/calibrated to it, which means the sub is now outputting 91dB rather than 95dB). It's the +10dB in-band relationship that's important, so you don't have to raise your centre speaker's output to 85dB in-band, you can leave it at 85dB full band (which is about 81dB in-band) and set the sub array 10dB higher than that (which would be about 91dB). You wouldn't want to do the sub level calibration without an RTA, as neither the centre speaker nor sub array are going to have a flat response (within the band limit) but if you don't have an RTA or, as in this case, if you are referencing dBSPL(C) measurements, then the front speakers should be at 85dB while the subs are at (about) 91dB.

This however is all for theatrical reproduction, where there is no bass management. In a home situation (with bass management) you can't simply use the method above to turn the sub up, because you'd end up with all the redirected bass freqs being 10dB too loud, it's only the LFE channel that needs 10dB of in-band gain. Fortunately, the consumer doesn't typically have to bother themselves with this, the AVR or (sub itself) will add the boost to the LFE channel it's receiving BEFORE it merges that LFE channel with the redirected bass. This is only an issue for those manually calibrating their sub.

G

 

[Phronesis]

No takers on thoughts on headphone testing? Aside from initial thoughts from JoeBloggs, it’s crickets. Where’s the passion for sorting out truth from illusion in a practical way?

 

[castleofargh]

No takers on thoughts on headphone testing? Aside from initial thoughts from JoeBloggs, it’s crickets. Where’s the passion for sorting out truth from illusion in a practical way?

what do you want to test? headphones tend to be clearly different from each other so there is no point in trying to set up a blind test for audibility of the differences. and measurements will be more relevant for most other questions you may have. so what's left would be about personal preference, but it's hard to forget about weight, clamping force, how much we sweat when we wear some... IMO those are perfectly relevant variables for a preference assessment, even if it goes well beyond preference of sound.
just volume matching requires some imagination when 2 headphones don't have the same FR.