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Post by marcl on Jul 20, 2021 12:17:51 GMT -5
As I interpret what he's saying... he's saying that, with a single listening position, the improvements you get with multiple subs aren't important.
He basically said: "While there might be improvements with multiple subs... you could get the same results with just EQ... which is easier and cheaper."
The thing that surprised me the most was when he was talking about a conversation with a guy, and when the guy told him he had one listening position Welti told him multiple subs wouldn't be worth doing. That is just weird! I understand the benefits of multiple subs for evening out response over a wider area than one seat. But the physics of waves propagating from opposite ends of the room, cancellation of some harmonic resonances ... and the fact that it's easily measurable at a single point that multiple subs improve the response ... very strange to me that he would say that. Yes that's what is surprising. Because even for a single listening position, multiple - even just two - subs can fill in nulls that you can't fix with EQ. That's the case in my system. The two subs fill in the gaps to the point that EQ (or Dirac) can do the rest quite well. |
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richb
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Post by richb on Jul 20, 2021 12:44:25 GMT -5
As I interpret what he's saying... he's saying that, with a single listening position, the improvements you get with multiple subs aren't important.
He basically said: "While there might be improvements with multiple subs... you could get the same results with just EQ... which is easier and cheaper." Yes that's what is surprising. Because even for a single listening position, multiple - even just two - subs can fill in nulls that you can't fix with EQ. That's the case in my system. The two subs fill in the gaps to the point that EQ (or Dirac) can do the rest quite well. And, the LFE channel goes up to 150 Hz where it can be localized. IME, Two is better than one. - Rich |
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Post by marcl on Jul 20, 2021 12:59:52 GMT -5
Yes that's what is surprising. Because even for a single listening position, multiple - even just two - subs can fill in nulls that you can't fix with EQ. That's the case in my system. The two subs fill in the gaps to the point that EQ (or Dirac) can do the rest quite well. And, the LFE channel goes up to 150 Hz where it can be localized. IME, Two is better than one. - Rich Yes, I think the Dolby spec is 120Hz and it rolls off 12db/octave above that. And if you use subs for bass management you might have crossovers up to 200 or 250. Most of my speakers cross at 100 but my Magnepan CC5 crosses at 200Hz. I can definitely localize that sound if it's off center. I have dips in my room between 60 and 200 so the two subs fill those pretty well. |
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Post by marcl on Jul 20, 2021 13:39:29 GMT -5
There is essentially no way that a microphone can truly separate direct from reflected sound in a real room. The best you can do is to use a very short sampling window to "catch the direct sound but stop listening before the reflected sound has time to arrive". This will give you a result that is approximately equivalent to an anechoic response.
You can then sample using a longer window, which will measure the sum of both, then assume that the difference is mostly the reflected sound. Although the fact that cancellations can occur between them means that the results will not be perfect.
(In theory you could also exclude the shorter arrival times from the measurement window and read mostly reflections from room acoustics.) (Also note that, if your walls are different, then reflections from each will also be different, and you would really want to measure the reflections from each separately.)
Obviously, in order to fully characterize the speakers and the room, you would need a LOT of measurements.
The bottom line is that Dirac Live is using some fancy math to allow it to get a good idea of all of this with a relatively few measurements. Then it uses some even fancier math to attempt to figure out what's wrong, decide what can or should be fixed, and then fix it.
And it's all still going to work better if your room is good, and reasonably symmetrical, to begin with.
Time alignment is, at least in principle, a lot simpler. Your brain uses the relative arrival times of non-periodic sounds to determine the apparent location of the source.
If they don't agree between your speakers then your brain will end up with the equivalent of "a blurry image of the sound stage". (And, if it's really off, then things can sound very odd indeed.)
So, by fixing that, you can create a sharper and more accurate sound stage image. (Note that you need to examine both the overall arrival time of sounds from multiple speakers and the variation of arrival time with frequency for each individual speaker.)
Filter implementation can be optimized to both reduce pre-ringing and post-ringing and both. The more "taps" the better but that would be hardware dependent. However, time-aligning is another matter since that is related to frequency but Dirac measures using mics that are not that great at separating direct and indirect. If you like it, use it, but if the results are not repeatable above Schroeder, then it is it really trial, error, and entirely subjective. - Rich And time windowing has issues at low frequencies where the wavelengths are so long that the direct wave hasn't finished when the reflections start arriving. So enter the Klippel NFS, which apparently solves these issue and does differentiate direct and reflected waves to give you anechoic response in your garage ... for a little more than $100k depending on options. Not that we want to measure anechoic response in our room, that would defeat the purpose of room correction. Here's a long and technical discussion of the NFS: www.youtube.com/watch?v=-s-R1HCYUYsI'll do a pattern of measurements soon - maybe 9 points in a 2ft cube around the MLP, just one speaker - and post the variation in amplitude response vs the variation in impulse response. I'll postulate that the latter will vary most after 10-20ms. |
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Post by marcl on Jul 21, 2021 11:15:49 GMT -5
Okay FWIW I did a quick five measurements of my Center channel. Dirac is active with a flat target curve. Crossover is 70Hz to the large fronts and subs. Bass boost below 70Hz is due to the BM bug. I measured at the MLP, then a foot in front +, behind -, left L and right R of the MLP. The behind measurement was a few inches behind the couch and a few inches above the seat back. Frequency Amplitude response plot with Variable Smoothing:  Variation as expected, but wow ... I'm glad I never sit behind the couch! The behind measurement showed a blip in phase shift too ... right there above 55Hz. And note that everything from 70Hz down to 40Hz on all plots is coming from the L/R fronts in mono, and below 40Hz from the front/rear subs in mono. And above 1KHz - where those short wavelengths are - not really that much deviation. Impulse Response:  Yes they're all stacked up, But what you can see is the variation is all in very early reflections within less than 3ms. So can we learn anything from this? Well for one thing, my guess that we'd see variation later than 10ms was totally wrong!  |
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Post by okjazz on Jul 21, 2021 11:34:46 GMT -5
Okay FWIW I did a quick five measurements of my Center channel. Dirac is active with a flat target curve. Crossover is 70Hz to the large fronts and subs. Bass boost below 70Hz is due to the BM bug. I measured at the MLP, then a foot in front +, behind -, left L and right R of the MLP. The behind measurement was a few inches behind the couch and a few inches above the seat back. Frequency Amplitude response plot with Variable Smoothing: View AttachmentVariation as expected, but wow ... I'm glad I never sit behind the couch! The behind measurement showed a blip in phase shift too ... right there above 55Hz. And note that everything from 70Hz down to 40Hz on all plots is coming from the L/R fronts in mono, and below 40Hz from the front/rear subs in mono. And above 1KHz - where those short wavelengths are - not really that much deviation. Impulse Response: View AttachmentYes they're all stacked up, But what you can see is the variation is all in very early reflections within less than 3ms. So can we learn anything from this? Well for one thing, my guess that we'd see variation later than 10ms was totally wrong! What do you mean when you said "Bass boost below 70Hz is due to the BM bug"? What bug are you talking about? |
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Post by marcl on Jul 21, 2021 11:48:52 GMT -5
Okay FWIW I did a quick five measurements of my Center channel. Dirac is active with a flat target curve. Crossover is 70Hz to the large fronts and subs. Bass boost below 70Hz is due to the BM bug. I measured at the MLP, then a foot in front +, behind -, left L and right R of the MLP. The behind measurement was a few inches behind the couch and a few inches above the seat back. Frequency Amplitude response plot with Variable Smoothing: View AttachmentVariation as expected, but wow ... I'm glad I never sit behind the couch! The behind measurement showed a blip in phase shift too ... right there above 55Hz. And note that everything from 70Hz down to 40Hz on all plots is coming from the L/R fronts in mono, and below 40Hz from the front/rear subs in mono. And above 1KHz - where those short wavelengths are - not really that much deviation. Impulse Response: View AttachmentYes they're all stacked up, But what you can see is the variation is all in very early reflections within less than 3ms. So can we learn anything from this? Well for one thing, my guess that we'd see variation later than 10ms was totally wrong! What do you mean when you said "Bass boost below 70Hz is due to the BM bug"? What bug are you talking about? It's described in detail here: emotivalounge.proboards.com/thread/58985/g3p-elevated-bm-lfe-issueBasically, since FW2.2/2.3, when you configure a speaker as small and send its bass to one or more subs or to large speakers, the small speaker bass is boosted at least 5db by Bass Management (BM). There is no workaround for this. If the bass is sent to two large front speakers, that adds 3db for a total of 8db boost. This extra 3db is a separate bug due to not accounting for the gain resulting from two speakers playing the bass in mono. |
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Post by napsterau on Jul 21, 2021 18:43:55 GMT -5
Fired up my EDNIB and ran some calibrations last night and just can't get a win.
I have to be doing something wrong.
Mic volume was set to achieve -30dB
Channels set to achieve -15dB
Run calibration across MLP, L, R, FL, FR to get 5 different locations.
The curtains did pickup almost full range for most speakers except for my ceiling speakers which limited the curtain to about 2.8khz but shouldn't have resulted in a lifeless soundstage.
The outcome was a complete loss of bass and felt like me ears were blocked.
The LCR's no longer sound like they output much bass at all either.
My preset with just speaker distances and levels set sounds fantastic so not sure how I am screwing up the Dirac calibration.
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ttocs
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Post by ttocs on Jul 21, 2021 19:24:03 GMT -5
Fired up my EDNIB and ran some calibrations last night and just can't get a win. I have to be doing something wrong. Mic volume was set to achieve -30dB Channels set to achieve -15dB Run calibration across MLP, L, R, FL, FR to get 5 different locations. The curtains did pickup almost full range for most speakers except for my ceiling speakers which limited the curtain to about 2.8khz but shouldn't have resulted in a lifeless soundstage. The outcome was a complete loss of bass and felt like me ears were blocked. The LCR's no longer sound like they output much bass at all either. My preset with just speaker distances and levels set sounds fantastic so not sure how I am screwing up the Dirac calibration. Try a single mic location first, keep it simple. Put the Mic at 100%. Start with Master extremely low, play pink noise on every channel to get the meters "settled" into a starting position, about two seconds for each channel. Look for the channel with the lowest output and play the pink noise for that channel, in my system it's always the Surround Left, then move the Master slider up until you get the volume level you want for that channel, then stop playing the pink noise. Now you can adjust all the other sliders, with no noise, until they all match the first channel you already set. When this is finished, go to the next step. I shoot for about -26dB to -25dB when pink noise is playing for speakers, and a few dB higher for subs. This makes it loud enough but not dangerous to speakers or subs. This takes me about a minute to do. It took me longer to type. Run the sweeps for the one mic position, save the session before proceeding, then go to the next step which will bring up a nag screen "are you sure?" and yes, you're sure, so get to the next page and wait for the computing magic to happen, then go load the filter into the processor. I will always suggest doing the most simple process first to see what happens, then build on the results. Now you can compare 1-spot mic to 5-spot mic runs. Also, you need to be certain that the mic can see every speaker directly. If a speaker is not clearly visible to the mic, then the mic is hearing reflections. |
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Post by napsterau on Jul 21, 2021 20:52:33 GMT -5
Fired up my EDNIB and ran some calibrations last night and just can't get a win. I have to be doing something wrong. Mic volume was set to achieve -30dB Channels set to achieve -15dB Run calibration across MLP, L, R, FL, FR to get 5 different locations. The curtains did pickup almost full range for most speakers except for my ceiling speakers which limited the curtain to about 2.8khz but shouldn't have resulted in a lifeless soundstage. The outcome was a complete loss of bass and felt like me ears were blocked. The LCR's no longer sound like they output much bass at all either. My preset with just speaker distances and levels set sounds fantastic so not sure how I am screwing up the Dirac calibration. Try a single mic location first, keep it simple. Put the Mic at 100%. Start with Master extremely low, play pink noise on every channel to get the meters "settled" into a starting position, about two seconds for each channel. Look for the channel with the lowest output and play the pink noise for that channel, in my system it's always the Surround Left, then move the Master slider up until you get the volume level you want for that channel, then stop playing the pink noise. Now you can adjust all the other sliders, with no noise, until they all match the first channel you already set. When this is finished, go to the next step. I shoot for about -26dB to -25dB when pink noise is playing for speakers, and a few dB higher for subs. This makes it loud enough but not dangerous to speakers or subs. This takes me about a minute to do. It took me longer to type. Run the sweeps for the one mic position, save the session before proceeding, then go to the next step which will bring up a nag screen "are you sure?" and yes, you're sure, so get to the next page and wait for the computing magic to happen, then go load the filter into the processor. I will always suggest doing the most simple process first to see what happens, then build on the results. Now you can compare 1-spot mic to 5-spot mic runs. Also, you need to be certain that the mic can see every speaker directly. If a speaker is not clearly visible to the mic, then the mic is hearing reflections. Thanks very much, will give that a go tonight. How does Dirac handle phase between LCR and Subs? I feel like the Subs might be cancelling out the LCR's in the lower frequencies. |
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Post by marcl on Jul 22, 2021 12:47:27 GMT -5
Try a single mic location first, keep it simple. Put the Mic at 100%. Start with Master extremely low, play pink noise on every channel to get the meters "settled" into a starting position, about two seconds for each channel. Look for the channel with the lowest output and play the pink noise for that channel, in my system it's always the Surround Left, then move the Master slider up until you get the volume level you want for that channel, then stop playing the pink noise. Now you can adjust all the other sliders, with no noise, until they all match the first channel you already set. When this is finished, go to the next step. I shoot for about -26dB to -25dB when pink noise is playing for speakers, and a few dB higher for subs. This makes it loud enough but not dangerous to speakers or subs. This takes me about a minute to do. It took me longer to type. Run the sweeps for the one mic position, save the session before proceeding, then go to the next step which will bring up a nag screen "are you sure?" and yes, you're sure, so get to the next page and wait for the computing magic to happen, then go load the filter into the processor. I will always suggest doing the most simple process first to see what happens, then build on the results. Now you can compare 1-spot mic to 5-spot mic runs. Also, you need to be certain that the mic can see every speaker directly. If a speaker is not clearly visible to the mic, then the mic is hearing reflections. Thanks very much, will give that a go tonight. How does Dirac handle phase between LCR and Subs? I feel like the Subs might be cancelling out the LCR's in the lower frequencies. Some good interviews describing how DL works and also a bit about DLBC in the second: audiophilestyle.libsyn.com/dirac-research-interviewwww.youtube.com/watch?v=YLfT7jwTm2w&t=1sRemember that most every room has a BIG peak somewhere between 40 and 60Hz. One of the most important things Dirac does is flatten that peak. So it may feel like "less" bass, but it is actually accurate bass. From there you can add a house curve to your own taste. Dirac also makes sure all speakers are in phase, and it will flip polarity of any that are not. |
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Post by napsterau on Jul 22, 2021 17:23:01 GMT -5
Thanks very much, will give that a go tonight. How does Dirac handle phase between LCR and Subs? I feel like the Subs might be cancelling out the LCR's in the lower frequencies. Some good interviews describing how DL works and also a bit about DLBC in the second: audiophilestyle.libsyn.com/dirac-research-interviewwww.youtube.com/watch?v=YLfT7jwTm2w&t=1sRemember that most every room has a BIG peak somewhere between 40 and 60Hz. One of the most important things Dirac does is flatten that peak. So it may feel like "less" bass, but it is actually accurate bass. From there you can add a house curve to your own taste. Dirac also makes sure all speakers are in phase, and it will flip polarity of any that are not. Nice thanks. I thought this would be the case but it does feel like the Sub and Mains cancel each other out. Will report back once I have run calibration again. |
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Post by hsamwel on Jul 25, 2021 16:06:01 GMT -5
Folks at Dirac (and others) recommend the legendary "Harman Curves". Here's a recent interview with Todd Welti (Distinguished Engineer at Harman). Todd wrote the well-known paper on multiple subwoofers many years ago. In this interview he starts talking about multiple subs around minute 18. Around minute 56 he's talking about headphone design, and he gets to the origin of the "Harman Target Curves". He clearly says that these curves were the result of listener studies on their preferences for the sound of headphones. Headphones! Not a target curve for EQ'ing speakers ... headphones! The intent of the curves is to design headphones that have a response that is preferred by many listeners. And, he says that trained listeners tend to prefer flatter response, and untrained listeners tend to prefer the more exaggerated curves with boosted bass. Just sayin' www.youtube.com/watch?v=V-6goLs1szMThis is correct.. At reference level! The way most people are listening, 10-20db lower the bass needs to be raised to be percieved by our hearing as the same volume. We hear midrange much better and bass worse the lower it gets in volume. |
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Post by marcl on Jul 25, 2021 16:21:02 GMT -5
Folks at Dirac (and others) recommend the legendary "Harman Curves". Here's a recent interview with Todd Welti (Distinguished Engineer at Harman). Todd wrote the well-known paper on multiple subwoofers many years ago. In this interview he starts talking about multiple subs around minute 18. Around minute 56 he's talking about headphone design, and he gets to the origin of the "Harman Target Curves". He clearly says that these curves were the result of listener studies on their preferences for the sound of headphones. Headphones! Not a target curve for EQ'ing speakers ... headphones! The intent of the curves is to design headphones that have a response that is preferred by many listeners. And, he says that trained listeners tend to prefer flatter response, and untrained listeners tend to prefer the more exaggerated curves with boosted bass. Just sayin' www.youtube.com/watch?v=V-6goLs1szMThis is correct.. At reference level! The way most people are listening, 10-20db lower the bass needs to be raised to be percieved by our hearing as the same volume. We hear midrange much better and bass worse the lower it gets in volume. Yes but .... 1 - what is reference level? It's not ear-splitting 110db, it's an average of 75db (depending what spec you look at) at the listening position 2 - If you listen substantially below that level, compensation for our low level perception of bass is the stuff of Fletcher-Munson curves, and the job of variable compensation provided by Loudness. Not a "hard coded" +4, +6 or +8 3 - if you "hard code" a bias like that, you can't listen at reference level without unnaturally exaggerated bass The main point though is ... the "Harman Curves" were neither derived nor intended for this purpose. Of course, if people want boosted bass ... it's their prerogative ... but it isn't justifiable as anything but arbitrary personal preference. |
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Post by hsamwel on Jul 26, 2021 7:47:32 GMT -5
This is correct.. At reference level! The way most people are listening, 10-20db lower the bass needs to be raised to be percieved by our hearing as the same volume. We hear midrange much better and bass worse the lower it gets in volume. Yes but .... 1 - what is reference level? It's not ear-splitting 110db, it's an average of 75db (depending what spec you look at) at the listening position 2 - If you listen substantially below that level, compensation for our low level perception of bass is the stuff of Fletcher-Munson curves, and the job of variable compensation provided by Loudness. Not a "hard coded" +4, +6 or +8 3 - if you "hard code" a bias like that, you can't listen at reference level without unnaturally exaggerated bass The main point though is ... the "Harman Curves" were neither derived nor intended for this purpose. Of course, if people want boosted bass ... it's their prerogative ... but it isn't justifiable as anything but arbitrary personal preference. I agree regarding the Harman curves.. But what is ”correct” with each persons used volume is really hard to figure out. If you use Harman 10dB and listen to reference volume (according to THX standard) with calibrated bass. You CERTAINLY have too much bass is the room. Also with a flat curve you’ll have to much treble if listening to reference.. The Loudness feature in RMC just sound strange. The clarity just goes away. Probably because I use Dirac and not a completely flat curve. Or I’m not used to that kind of sound..  But when the midrange is at 75db the bass needs to be alot higher to be precieved as the same volume. When you reach enough volume they are precieved as the same. Then flat is the correct setting for most sound. Exact dB of this I don’t know.. I read that if bass reaches 105 dB it’s precieved as the same as midrange. But the picture bellow tell otherwise. That’s why most people like to use the Harman curves.. As most don’t like to watch movies in small rooms in that kind of volume. Many times peoples settings for bass is because of their room.. If you sit in a great place bass wise you often don’t need to extend the bass. I found this picture to illustrate our hearing. Notice how the limit/threshold tilts towards the treble. Probably why Dirac chose their default curve. Attachments:
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Post by marcl on Jul 26, 2021 10:44:04 GMT -5
Yes but .... 1 - what is reference level? It's not ear-splitting 110db, it's an average of 75db (depending what spec you look at) at the listening position 2 - If you listen substantially below that level, compensation for our low level perception of bass is the stuff of Fletcher-Munson curves, and the job of variable compensation provided by Loudness. Not a "hard coded" +4, +6 or +8 3 - if you "hard code" a bias like that, you can't listen at reference level without unnaturally exaggerated bass The main point though is ... the "Harman Curves" were neither derived nor intended for this purpose. Of course, if people want boosted bass ... it's their prerogative ... but it isn't justifiable as anything but arbitrary personal preference. I agree regarding the Harman curves.. But what is ”correct” with each persons used volume is really hard to figure out. If you use Harman 10dB and listen to reference volume (according to THX standard) with calibrated bass. You CERTAINLY have too much bass is the room. Also with a flat curve you’ll have to much treble if listening to reference.. The Loudness feature in RMC just sound strange. The clarity just goes away. Probably because I use Dirac and not a completely flat curve. Or I’m not used to that kind of sound.. But when the midrange is at 75db the bass needs to be alot higher to be precieved as the same volume. When you reach enough volume they are precieved as the same. Then flat is the correct setting for most sound. Exact dB of this I don’t know.. I read that if bass reaches 105 dB it’s precieved as the same as midrange. But the picture bellow tell otherwise. That’s why most people like to use the Harman curves.. As most don’t like to watch movies in small rooms in that kind of volume. Many times peoples settings for bass is because of their room.. If you sit in a great place bass wise you often don’t need to extend the bass. I found this picture to illustrate our hearing. Notice how the limit/threshold tilts towards the treble. Probably why Dirac chose their default curve. The Loudness in the RMC/XMC is implemented for stereo in a way that seems useful, if you happen to listen at the levels that were assumed when the feature was implemented. For multichannel the Loudness is broken to the point of being potentially damaging. Loudness controls on receivers 30 years ago worked correctly, as I recall. But here's something that just occurred to me ... the music we listen to was mixed by humans listening to speakers in a room. I would then conclude that those humans already compensated for the nonlinearity of human hearing when they mixed and mastered the recording. So all we have to do is listen to a flat response in a well-treated and/or corrected room. |
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Post by hsamwel on Jul 26, 2021 10:57:13 GMT -5
^^^^ +1 Please read the above post carefully. It's absolutely correct. Dolby has one subwoofer channel, and it's called the .1 channel. Over time the .1 channel got all mixed up in A/V systems being able to use smaller and smaller speakers and satellites necessitating the usage of subwoofers for proper bass, but these subwoofers should have ALWAYS been totally separate from the .1 subwoofer channel. One subwoofer channel for the .1, and one subwoofer channel for screen speakers and satellites which cannot produce the specified bass. I'll go further with this. Any processor capable 5.1 surround or more should be required to have a .1 channel, and offer a Bass Management subwoofer channel. Keep them separate. If you keep them separate (LFE and BM) you’ll probably end up with nulls in the room. Unless you somehow calibrate ALL bass capable speakers together like DLBC does. So until we get DLBC it would be recommended to use a singel channel bass output and even small for all speakers. For multi channel output anyway. I don’t know a way to calibrate large speakers together with LFE subs in REW, do you? Maybe it’s possible? But then you’ll have to ditch DL as it would mess with its calibration of each channel. |
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Post by hsamwel on Jul 26, 2021 11:22:52 GMT -5
I agree regarding the Harman curves.. But what is ”correct” with each persons used volume is really hard to figure out. If you use Harman 10dB and listen to reference volume (according to THX standard) with calibrated bass. You CERTAINLY have too much bass is the room. Also with a flat curve you’ll have to much treble if listening to reference.. The Loudness feature in RMC just sound strange. The clarity just goes away. Probably because I use Dirac and not a completely flat curve. Or I’m not used to that kind of sound.. But when the midrange is at 75db the bass needs to be alot higher to be precieved as the same volume. When you reach enough volume they are precieved as the same. Then flat is the correct setting for most sound. Exact dB of this I don’t know.. I read that if bass reaches 105 dB it’s precieved as the same as midrange. But the picture bellow tell otherwise. That’s why most people like to use the Harman curves.. As most don’t like to watch movies in small rooms in that kind of volume. Many times peoples settings for bass is because of their room.. If you sit in a great place bass wise you often don’t need to extend the bass. I found this picture to illustrate our hearing. Notice how the limit/threshold tilts towards the treble. Probably why Dirac chose their default curve. The Loudness in the RMC/XMC is implemented for stereo in a way that seems useful, if you happen to listen at the levels that were assumed when the feature was implemented. For multichannel the Loudness is broken to the point of being potentially damaging. Loudness controls on receivers 30 years ago worked correctly, as I recall. But here's something that just occurred to me ... the music we listen to was mixed by humans listening to speakers in a room. I would then conclude that those humans already compensated for the nonlinearity of human hearing when they mixed and mastered the recording. So all we have to do is listen to a flat response in a well-treated and/or corrected room. Oh, I didn’t know that. Can you use Loudness with Stereo mode (with Dirac)? What happens if you use a Harman curve with your Dirac calibration? What’s the issue with multi channel Loudness then? I don’t think they can mix the sound nonlinear like you suggest because what happens with systems that play really loud then? Which don’t even have Dirac? Many full range speakers already are a bit Harman ”calibrated” from factory.. Even more so when placed in small rooms near walls. That would make the bass unbearable if played really loud. Some recordings are really bass heavy though.. But generally I wouldn’t think. I think this is a choice from the artists and the mixer/producer really. |
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Post by hsamwel on Jul 26, 2021 11:38:00 GMT -5
I should add, however, that Dirac Live and REW don't measure things the same way...
Therefore, while you can compare REW measurements from before a correction to REW measurements from after...
You should NOT necessarily expect graphs and measurements produced by REW to match those produced by Dirac Live...
No. Use REW before/after with both USER EQ and Dirac EQ. Setup one Preset for a Dirac EQ, and the other Preset for USER EQ. This will let you set the Levels for the USER EQ, and tweak the Levels for the Dirac EQ after running Dirac. Once set, use REW. This is the true before and after, USER and Dirac. I measure before/after with every Dirac run. True and not true.. They measure the same, but Dirac does more with the data it recieves than change the frequency response. Magnitude (frequency) response you can compare.. But anything else is really up to your ears.. |
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Post by ttocs on Jul 26, 2021 11:40:01 GMT -5
^^^^ +1 Please read the above post carefully. It's absolutely correct. Dolby has one subwoofer channel, and it's called the .1 channel. Over time the .1 channel got all mixed up in A/V systems being able to use smaller and smaller speakers and satellites necessitating the usage of subwoofers for proper bass, but these subwoofers should have ALWAYS been totally separate from the .1 subwoofer channel. One subwoofer channel for the .1, and one subwoofer channel for screen speakers and satellites which cannot produce the specified bass. I'll go further with this. Any processor capable 5.1 surround or more should be required to have a .1 channel, and offer a Bass Management subwoofer channel. Keep them separate. If you keep them separate (LFE and BM) you’ll probably end up with nulls in the room. Unless you somehow calibrate ALL bass capable speakers together like DLBC does. So until we get DLBC it would be recommended to use a singel channel bass output and even small for all speakers. For multi channel output anyway. I don’t know a way to calibrate large speakers together with LFE subs in REW, do you? Maybe it’s possible? But then you’ll have to ditch DL as it would mess with its calibration of each channel. I keep BM and LFE separate and together. See diagram. I do not use all Mono subwoofer channels because there is much to gain by being able to adjust the level of BM and LFE individually, so, Center Sub Output is LFE, Left Sub Output is Mono. I use REW so I can adjust all the Small channels to match the Large Channels above the XO of the Smalls, then I adjust the Left Sub Mono to be the same level as the Smalls. I do not use Levels in the processor because it doesn't work like it used to. I use a particular sound field, Surround, and adjust for that specific one for movies. I now use Preset 1 for Dirac, and Preset 2 for User, and setup each for maximum speakers installed so then I can reduce the speaker count if I want to check something. The same three subwoofers provide BM and LFE. Separated at birth, together again at last.  Yes, I calibrate my Large Speakers and Subwoofers individually and as a group for multi-use. Each Front Speaker is tweaked, then BOTH Front Speakers together are tweaked, and it's a back and forth to see what works. I use a subwoofer in the back of the room to help smooth the response from when either Front Speaker is playing and when Both Front Speakers are playing. Without DLBC I've taken to having fun without it. |
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