How to Choose a Loudspeaker -- What the Science Shows - Page 164 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 6377Likes
Reply
 
Thread Tools
post #4891 of 5313 Old 09-13-2019, 12:04 PM
Senior Member
 
Join Date: Mar 2019
Location: Russia
Posts: 344
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 69
Quote:
Originally Posted by motrek View Post
Just because a speaker has higher or lower sensitivity doesn't mean it performs better or worse at certain volumes, at least not to my knowledge.

What makes you think that a speaker with higher sensitivity would perform better at higher volumes, which is what it would be tested at in your world?

And does that mean that speakers with lower sensitivity should be super quiet and difficult to hear, in your ideal testing environment?

What you're saying doesn't make any sense.
I never said that it is sensitivity (unless you are referring to the post before where I explained how sensitivity by itself is irrelevant to the SQ in my opinion).

Just from my experience you will find comfortable volume level different with different speakers. What is it I don't know. Maybe distortion?

What I want as "ideal" test environment is most likely impossible in real worlds (long term speaker comparison). Maybe make 2 setups at the same place and find out which place people come more often? I don't know how to do that.

Last edited by aats; 09-13-2019 at 12:07 PM.
aats is offline  
Sponsored Links
Advertisement
 
post #4892 of 5313 Old 09-13-2019, 12:08 PM
AVS Forum Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 8,771
Mentioned: 182 Post(s)
Tagged: 0 Thread(s)
Quoted: 3771 Post(s)
Liked: 3380
Quote:
Originally Posted by aats View Post
They can do whatever they like.


But for the end user it feels very strange to "level match".
How well speaker handles higher SPL is a part of performance for sure.

"Louder is better sounding" people often say, so why remove this characteristic from comparisons? Obviously SPL should be limited to not inflict hearing damage, but giving a user volume control to set "comfortable level" with each speaker seems like a good idea to me
But I also think you can only evaluate a speaker over a long time rather than in a quick comparison.
The Harman testing allows volume adjustments as far as I recall, but I would assume preference voting would only be allowed between the speakers when at the same level matched SPL. In other words, once the volume is selected, switching between speakers would occur.

Dr. Toole might be able to clarify or @Kal Rubinson
Gooddoc is offline  
post #4893 of 5313 Old 09-13-2019, 12:55 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by Gooddoc View Post
The Harman testing allows volume adjustments as far as I recall, but I would assume preference voting would only be allowed between the speakers when at the same level matched SPL. In other words, once the volume is selected, switching between speakers would occur.

Dr. Toole might be able to clarify or @Kal Rubinson
Although it is good practice to adjust loudspeakers being compared to be at the same loudness level, it is an inherently flawed process because loudspeakers can have quite different frequency responses. So, the precision of the loudness match is best for the better - more neutral, more similar sounding - loudspeakers.

Does it matter? It depends. In the early days of my research I did comparison tests with matched and unmatched loudness. Back then many loudspeakers had clearly audible resonances, and these loudspeakers were identified and downgraded even with mismatched loudness. The more neutral the loudspeaker the more critical the loudness match, and here the dominant factor is subjective loudness - described by the equal-loudness contours. This means that differences in overall sound level are perceived as differences in bass balance. Since bass accounts for about 30% of our overall sound quality ratings, such differences have a magnified influence. Speakers having different low-frequency extension are especially influenced.

Otherwise, the vast majority of loudspeakers are so well designed that non-linear distortion and power compression are not issues unless the products are driven to extremely high sound levels - at which point the non-linearities of our hearing gets into the act.

In summary - sensitivity, per se, is not a factor unless the power amps are driven beyond their linear and stable current and voltage ranges for speakers with low sensitivity and/or low impedance - which happens. See Part 3 of the Designing a Home Theater series on the companion website for the 3rd edition of my book: www.routledge.com/cw/toole. Click on the title at the top of the webpage and download. It is open access, no need to buy the book.

A final comment, speakers with very high sensitivities tend to be horn loaded. These exhibit very different (narrower) directivity compared to cones and domes. This alone can account for significant differences in speaker/room interactions and perceptions.
Gooddoc, DonH50, motrek and 4 others like this.
Floyd Toole is offline  
Sponsored Links
Advertisement
 
post #4894 of 5313 Old 09-13-2019, 12:57 PM
Advanced Member
 
motrek's Avatar
 
Join Date: Dec 2013
Posts: 653
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 518 Post(s)
Liked: 191
Quote:
Originally Posted by aats View Post
I never said that it is sensitivity (unless you are referring to the post before where I explained how sensitivity by itself is irrelevant to the SQ in my opinion).

Just from my experience you will find comfortable volume level different with different speakers. What is it I don't know. Maybe distortion?
You were complaining about level matching (or at least saying it's a strange idea)... level matching is only done to get two speakers with different sensitivities to play at the same volume... otherwise it's not called level matching, it's called "just choosing whatever volume you want."
motrek is offline  
post #4895 of 5313 Old 09-13-2019, 01:02 PM
Senior Member
 
Join Date: Mar 2019
Location: Russia
Posts: 344
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 69
Quote:
Originally Posted by motrek View Post
You were complaining about level matching (or at least saying it's a strange idea)... level matching is only done to get two speakers with different sensitivities to play at the same volume... otherwise it's not called level matching, it's called "just choosing whatever volume you want."
It is just impossible to do (well, maybe it is possible, the closer speakers get to the "ideal" the more possible it is), not "strange", probably a bad wording from me.
It makes more sense to me (although it is not scientific at all, but I am coming more from a consumer side) to have levels at some level selected by listeners for each speaker (with the limit to not inflict hearing damage, of course).

Last edited by aats; 09-13-2019 at 01:06 PM.
aats is offline  
post #4896 of 5313 Old 09-13-2019, 05:06 PM
AVS Forum Club Gold
 
craig john's Avatar
 
Join Date: Oct 2003
Location: Lancaster, PA
Posts: 11,796
Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 1338 Post(s)
Liked: 1573
Quote:
Originally Posted by Floyd Toole View Post
Although it is good practice to adjust loudspeakers being compared to be at the same loudness level, it is an inherently flawed process because loudspeakers can have quite different frequency responses. So, the precision of the loudness match is best for the better - more neutral, more similar sounding - loudspeakers.

Does it matter? It depends. In the early days of my research I did comparison tests with matched and unmatched loudness. Back then many loudspeakers had clearly audible resonances, and these loudspeakers were identified and downgraded even with mismatched loudness. The more neutral the loudspeaker the more critical the loudness match, and here the dominant factor is subjective loudness - described by the equal-loudness contours. This means that differences in overall sound level are perceived as differences in bass balance. Since bass accounts for about 30% of our overall sound quality ratings, such differences have a magnified influence. Speakers having different low-frequency extension are especially influenced.

Otherwise, the vast majority of loudspeakers are so well designed that non-linear distortion and power compression are not issues unless the products are driven to extremely high sound levels - at which point the non-linearities of our hearing gets into the act.

In summary - sensitivity, per se, is not a factor unless the power amps are driven beyond their linear and stable current and voltage ranges for speakers with low sensitivity and/or low impedance - which happens. See Part 3 of the Designing a Home Theater series on the companion website for the 3rd edition of my book: www.routledge.com/cw/toole. Click on the title at the top of the webpage and download. It is open access, no need to buy the book.

A final comment, speakers with very high sensitivities tend to be horn loaded. These exhibit very different (narrower) directivity compared to cones and domes. This alone can account for significant differences in speaker/room interactions and perceptions.
Very interesting. Your observations have just blown up a couple the axioms of this forum, one of which says that in order to appropriately compare speakers they MUST be level matched. Another axiom is that if they are not perfectly level-matched, the louder speaker will always be preferred, even if the difference is less than a dB! I've always wondered how one would level match speakers with different frequency responses, and now I have an answer... you can't. And since you can't, the rest of all that is just nonsense... just another forum myth.


Craig
SDX-LV and Scotth3886 like this.

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence."

My System
craig john is offline  
post #4897 of 5313 Old 09-13-2019, 05:21 PM
AVS Forum Special Member
 
aarons915's Avatar
 
Join Date: Oct 2012
Location: Cincinnati, OH
Posts: 1,314
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 879 Post(s)
Liked: 693
Quote:
Originally Posted by craig john View Post
Very interesting. Your observations have just blown up a couple the axioms of this forum, one of which says that in order to appropriately compare speakers they MUST be level matched. Another axiom is that if they are not perfectly level-matched, the louder speaker will always be preferred, even if the difference is less than a dB! I've always wondered how one would level match speakers with different frequency responses, and now I have an answer... you can't. And since you can't, the rest of all that is just nonsense... just another forum myth.


Craig
Not really, he's saying that when loudspeakers are drastically different in measurements, level-matching isn't necessary, these days speakers are much better and it's more necessary. I haven't found level-matching to be hugely critical but I still think it's important to get as close as possible just to eliminate a variable. I don't believe in using an SPL meter and just matching at 1000Hz, for example, I prefer to measure both speakers and estimate the SPL difference based on their room curves.
aarons915 is offline  
post #4898 of 5313 Old 09-13-2019, 05:38 PM
AVS Forum Special Member
 
Join Date: Dec 2016
Location: Las Vegas, NV
Posts: 1,601
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 1044 Post(s)
Liked: 1243
Every now and then we got money for new monitors and were able to get some in for listening tests. When I was doing the speaker comparisons, I tried to get them pretty well level matched with pink noise and program material using an SPL meter. It just puts them on a more level playing field. Back in those days, I was not attempting to do blind listening tests, but I did figure out it was OK to use one speaker in mono instead of two in stereo.
Rex Anderson is offline  
post #4899 of 5313 Old 09-13-2019, 07:13 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by craig john View Post
Very interesting. Your observations have just blown up a couple the axioms of this forum, one of which says that in order to appropriately compare speakers they MUST be level matched. Another axiom is that if they are not perfectly level-matched, the louder speaker will always be preferred, even if the difference is less than a dB! I've always wondered how one would level match speakers with different frequency responses, and now I have an answer... you can't. And since you can't, the rest of all that is just nonsense... just another forum myth.


Craig
For loudness matching the definitive test is subjective. There is NO technical measurement that can take into account all possible subtle or obvious timbral differences. However, if the speakers are essentially "identical" as you speculate, it is highly probable that the louder one will be preferred because the dominant difference will be the proportion of perceived bass. Bass is good, and too much bass is one of the "forgivable sins"

You can test this: just turn up the volume and decide if it sounds "better" - the speakers are unchanged. Because of the equal-loudness contours, differences will be most noticeable at low sound levels and less noticeable as sound levels rise.
R Harkness, motrek and SDX-LV like this.
Floyd Toole is offline  
post #4900 of 5313 Old 09-13-2019, 08:05 PM
Advanced Member
 
motrek's Avatar
 
Join Date: Dec 2013
Posts: 653
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 518 Post(s)
Liked: 191
Quote:
Originally Posted by craig john View Post
Very interesting. Your observations have just blown up a couple the axioms of this forum, one of which says that in order to appropriately compare speakers they MUST be level matched. Another axiom is that if they are not perfectly level-matched, the louder speaker will always be preferred, even if the difference is less than a dB! I've always wondered how one would level match speakers with different frequency responses, and now I have an answer... you can't. And since you can't, the rest of all that is just nonsense... just another forum myth.
...
I think you got Dr. Toole's post backwards. He said that back when speakers were worse, level matching was less important, because the better speaker would win regardless. Now that speakers are more neutral, it's more necessary to level-match according to equal-loudness contours.
BluesDaddy56 likes this.
motrek is offline  
post #4901 of 5313 Old 09-14-2019, 12:18 AM
AVS Forum Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,779
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 485 Post(s)
Liked: 469
Quote:
Originally Posted by aarons915 View Post
I personally find it a bit comical that anyone is questioning that setup, it appears to measure better than most of our "Hifi" setups. I think for the cost and size of the room you've done a superb job and I'm sure no one is going to complain about that sound during gym class...
I think the only salient question left to ask TimVG about the gym setup is, what brand/model of loudspeaker (and subwoofer) did he use?
krabapple is offline  
post #4902 of 5313 Old 09-14-2019, 08:35 AM
AVS Forum Special Member
 
Dave in Green's Avatar
 
Join Date: Jan 2014
Location: USA
Posts: 8,354
Mentioned: 152 Post(s)
Tagged: 0 Thread(s)
Quoted: 3787 Post(s)
Liked: 3001
Level matching is variable, not fixed. You can turn the volume of speakers being compared as low or as high as you want. The point is to compare how they sound when played at the same volume at any point on the volume scale you might want to listen.
Rex Anderson likes this.
Dave in Green is offline  
post #4903 of 5313 Old 09-15-2019, 11:00 AM
AVS Forum Special Member
 
aarons915's Avatar
 
Join Date: Oct 2012
Location: Cincinnati, OH
Posts: 1,314
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 879 Post(s)
Liked: 693
I have a question that @Floyd Toole and/or @SoundnWine could offer some insight to. I've been digging into some of the earlier listening studies regarding the mono/stereo tests and the Regression model for predicting loudspeaker preference and noticed a possible correlation between the high weightings of the On-axis sound and the way the tests are performed. I noticed in all of the setups, the speakers are pointed directly at the listener. Here is a snip of the early setups, I believe now the shuffler puts the speaker directly up front and center aimed straight at the listener.



Looking at the preference models, I saw for the Test 1 model the On-axis parameters were responsible for 45% of the weightings of the overall model while it's still 31.5% of the weighting in the generalized model. The Mono/Stereo listening study showed me that not only will the same speaker be preferred in Mono and stereo but also that placing a speaker in the front in Mono isn't going to change the preference compared to a more typical placement in the corner.

My question is do you believe the way the speakers are placed directly on-axis to the listener is going to bias the test and/or the preference model towards the On-axis sound relative to a more typical setup? By typical setup I mean the speaker being about 15 deg off-axis to the listener and closer to the side walls so that now the direct sound heard is actually closer to the listening window response and presumably more reflected sounds are now heard by the listener. I tried to do my homework as best I could but I am curious about your thoughts on the subject, thank you.
Attached Thumbnails
Click image for larger version

Name:	setup.JPG
Views:	84
Size:	43.6 KB
ID:	2615652  
Soulburner likes this.
aarons915 is offline  
post #4904 of 5313 Old 09-15-2019, 12:52 PM
Member
 
bearr48's Avatar
 
Join Date: Dec 2007
Posts: 93
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 30
Advice - deployment of side speakers

If a momentary change in topic is ok??

I have a pair of SVS Ultra towers (can't find any spin data), two subs, two Ultra Surrounds, and four SVS Prime elevation speakers. My room is abt 16' long, 8' hi & 11' wide. Given the narrow room, would it be better to employ the Surrounds as dipole side speakers, to minimize direct blasting into one ear of the listeners, and to use two of the Elevation speakers as left and right back surrounds, and the other two Elevation speakers as side ceiling speakers? Or put the Surrounds in back, or replace them with more direct-facing back surround speakers? I'm on my third reading of Dr. Toole's book, there's a lot to learn! I greatly appreciate the assembled expertise in this forum. Thanks again.
Jack
bearr48 is offline  
post #4905 of 5313 Old 09-15-2019, 03:13 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by aarons915 View Post
I have a question that @Floyd Toole and/or @SoundnWine could offer some insight to. I've been digging into some of the earlier listening studies regarding the mono/stereo tests and the Regression model for predicting loudspeaker preference and noticed a possible correlation between the high weightings of the On-axis sound and the way the tests are performed. I noticed in all of the setups, the speakers are pointed directly at the listener. Here is a snip of the early setups, I believe now the shuffler puts the speaker directly up front and center aimed straight at the listener.



Looking at the preference models, I saw for the Test 1 model the On-axis parameters were responsible for 45% of the weightings of the overall model while it's still 31.5% of the weighting in the generalized model. The Mono/Stereo listening study showed me that not only will the same speaker be preferred in Mono and stereo but also that placing a speaker in the front in Mono isn't going to change the preference compared to a more typical placement in the corner.

My question is do you believe the way the speakers are placed directly on-axis to the listener is going to bias the test and/or the preference model towards the On-axis sound relative to a more typical setup? By typical setup I mean the speaker being about 15 deg off-axis to the listener and closer to the side walls so that now the direct sound heard is actually closer to the listening window response and presumably more reflected sounds are now heard by the listener. I tried to do my homework as best I could but I am curious about your thoughts on the subject, thank you.
The key factor is that the first-arrival direct sound has a special place in the heirarchy of sounds arriving at a listener. You are asking, I think, if it matters whether that direct sound is the on-axis or 15 deg off axis sound delivered by the loudspeaker. The answer has to be dependent on how well the speaker was designed. In today's best products there is very little difference between the on-axis frequency response and that of the listening window that includes components up to 30 deg off axis. In such cases it very likely does not matter. In other designs there can be large differences, and these are problems - products to be avoided.

It is generally good practice to aim the speakers at the listeners because in most cases the on-axis sound has received special attention in the design process. Of course, the amount of sound reflected from the adjacent side wall is a factor, but this is a far off-axis, significantly attenuated component, especially if the speakers are aimed towards the prime listener. Again, what is heard will depend on the specifics of the speaker design.
vavan likes this.
Floyd Toole is offline  
post #4906 of 5313 Old 09-15-2019, 03:41 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by bearr48 View Post
If a momentary change in topic is ok??

I have a pair of SVS Ultra towers (can't find any spin data), two subs, two Ultra Surrounds, and four SVS Prime elevation speakers. My room is abt 16' long, 8' hi & 11' wide. Given the narrow room, would it be better to employ the Surrounds as dipole side speakers, to minimize direct blasting into one ear of the listeners, and to use two of the Elevation speakers as left and right back surrounds, and the other two Elevation speakers as side ceiling speakers? Or put the Surrounds in back, or replace them with more direct-facing back surround speakers? I'm on my third reading of Dr. Toole's book, there's a lot to learn! I greatly appreciate the assembled expertise in this forum. Thanks again.
Jack
I'm hoping that you made a typo when you wrote "dipole". If you indeed have read my book, Section15.8.3 shows the gross flaws in dipole (bidirectional-out-of-phase) surround loudspeakers. These are not to be used in any modern multichannel system, especially immersive systems, where all loudspeakers are required to deliver high quality, neutral, direct sound to all listeners.

As illustrated in that section Bipole (bidirectional-in-phase) loudspeakers are very different devices, capable of delivering excellent sound quality over the very wide dispersion angles required in small/narrow rooms with multiple rows (Figure 15.9).

Figure 15.8 shows suggested layouts in which the "side" surround speakers are placed forward of the prime listener. This alleviates some of the attention-getting problem of those speakers in narrow rooms, and at the same time improves the perception of envelopment which these speakers are primarily intended to deliver. The rear speakers deliver the fly-over illusions. The notion that side speakers need to be at 90 deg is based on a tradition beginning with the original 4 channel Dolby surround system - they simply haven't changed, even though there is good reason to do so. Don't confuse the customer.

Think of what is done in "reference" cinemas: there are "side surround" loudspeakers distributed along the entire side walls.

Last edited by Floyd Toole; 09-16-2019 at 08:50 AM.
Floyd Toole is offline  
post #4907 of 5313 Old 09-15-2019, 03:55 PM
AVS Forum Special Member
 
aarons915's Avatar
 
Join Date: Oct 2012
Location: Cincinnati, OH
Posts: 1,314
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 879 Post(s)
Liked: 693
Quote:
Originally Posted by Floyd Toole View Post
The key factor is that the first-arrival direct sound has a special place in the heirarchy of sounds arriving at a listener. You are asking, I think, if it matters whether that direct sound is the on-axis or 15 deg off axis sound delivered by the loudspeaker. The answer has to be dependent on how well the speaker was designed. In today's best products there is very little difference between the on-axis frequency response and that of the listening window that includes components up to 30 deg off axis. In such cases it very likely does not matter. In other designs there can be large differences, and these are problems - products to be avoided.

It is generally good practice to aim the speakers at the listeners because in most cases the on-axis sound has received special attention in the design process. Of course, the amount of sound reflected from the adjacent side wall is a factor, but this is a far off-axis, significantly attenuated component, especially if the speakers are aimed towards the prime listener. Again, what is heard will depend on the specifics of the speaker design.
Yes I agree that the direct sound is going to be very similar whether it's directly on-axis or 15 deg off axis, I guess my main question is, when the speaker is in the center of the room, will the side wall 1st reflections still be as much of a factor as if the speaker were closer to a side wall? I was just wondering if the way Harman conducts the blind listening tests is representative of the way most of us typically listen at home and I think that answer is yes after your response.

I think my answer might be in fig 3.13 on Pg 45 of the new book, it mentions the side walls were brought in closer to the center of the room in a later MLL configuration. I was thinking that may have been done to excite more of these side wall reflections, or maybe it was for a different reason altogether.

Last edited by aarons915; 09-15-2019 at 04:04 PM.
aarons915 is offline  
post #4908 of 5313 Old 09-15-2019, 04:55 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by aarons915 View Post
Yes I agree that the direct sound is going to be very similar whether it's directly on-axis or 15 deg off axis, I guess my main question is, when the speaker is in the center of the room, will the side wall 1st reflections still be as much of a factor as if the speaker were closer to a side wall? I was just wondering if the way Harman conducts the blind listening tests is representative of the way most of us typically listen at home and I think that answer is yes after your response.

I think my answer might be in fig 3.13 on Pg 45 of the new book, it mentions the side walls were brought in closer to the center of the room in a later MLL configuration. I was thinking that may have been done to excite more of these side wall reflections, or maybe it was for a different reason altogether.
The shuffler allows us to compare speakers in center or side locations and both have been done. A mono speaker on the one side is a distraction, and no changes in ratings were noted, so the center location was selected. The center channel is the most important channel in a multichannel system which is a consideration. Stereo images/sounds are corrupted by acoustical crosstalk and timbral/spatial differences related to the side-wall reflections, so ratings in mono have reason to be higher than those in stereo,

As seen in Figure 7.1, in a classic setup the side wall reflected sounds radiate at nearly 90 deg off axis, so sound levels are much reduced at medium and high frequencies. Also seen in the figure is the huge difference between sounds contributing to a phantom stereo center and a real center.

Pity that stereo is the norm
aarons915 and Karl Maga like this.
Floyd Toole is offline  
post #4909 of 5313 Old 09-15-2019, 05:51 PM
AVS Forum Special Member
 
aarons915's Avatar
 
Join Date: Oct 2012
Location: Cincinnati, OH
Posts: 1,314
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 879 Post(s)
Liked: 693
Quote:
Originally Posted by Floyd Toole View Post
The shuffler allows us to compare speakers in center or side locations and both have been done. A mono speaker on the one side is a distraction, and no changes in ratings were noted, so the center location was selected. The center channel is the most important channel in a multichannel system which is a consideration. Stereo images/sounds are corrupted by acoustical crosstalk and timbral/spatial differences related to the side-wall reflections, so ratings in mono have reason to be higher than those in stereo,

As seen in Figure 7.1, in a classic setup the side wall reflected sounds radiate at nearly 90 deg off axis, so sound levels are much reduced at medium and high frequencies. Also seen in the figure is the huge difference between sounds contributing to a phantom stereo center and a real center.

Pity that stereo is the norm
Thanks a lot, I figured the comparison was done between the center and the side locations, I've just never seen that comparison stated.
aarons915 is offline  
post #4910 of 5313 Old 09-15-2019, 08:13 PM
Member
 
bearr48's Avatar
 
Join Date: Dec 2007
Posts: 93
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 30
Thank you Dr. Toole for your reply. Yes, it was a typo and I meant to say bipole (a typo apparently duplicated in the second paragraph of your response. It was Section 15.8 that made me think of using the "Ultra Surrounds" as side speakers. Given that they are bipoles, should I still locate them forward from the main listening position, or would 90 degrees be better here?

Unrelated (kind of): High-frequency hearing loss, tinnitus (for me a high-pitched ringing sound), and inconsistent judgement of sound quality, all affect my enjoyment of music...I even sometimes sense distortion (IM, perhaps) that isn't really there, in live symphony performances! Growing old is truly not for sissies. Thank you again for your invaluable contributions to the body of knowledge.
bearr48 is offline  
post #4911 of 5313 Old 09-15-2019, 11:42 PM
AVS Forum Special Member
 
Soulburner's Avatar
 
Join Date: Oct 2007
Location: Lincoln
Posts: 4,883
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 1623
Dolby spec is 90-110 degrees:

Click image for larger version

Name:	7_1-surround-sound-speaker-placement.jpg
Views:	37
Size:	41.2 KB
ID:	2616052

I find I get better envelopment when they are more than 90 degrees (slightly behind) from me. YMMV.

HT: Samsung PN64H5000 (recommended settings) | NAD T758 V3 | Buchardt S400 (2) | Emotiva E2 (2) | Rythmik Audio F12 (2)
Soulburner is offline  
post #4912 of 5313 Old 09-16-2019, 09:09 AM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by bearr48 View Post
Thank you Dr. Toole for your reply. Yes, it was a typo and I meant to say bipole (a typo apparently duplicated in the second paragraph of your response. It was Section 15.8 that made me think of using the "Ultra Surrounds" as side speakers. Given that they are bipoles, should I still locate them forward from the main listening position, or would 90 degrees be better here?

Unrelated (kind of): High-frequency hearing loss, tinnitus (for me a high-pitched ringing sound), and inconsistent judgement of sound quality, all affect my enjoyment of music...I even sometimes sense distortion (IM, perhaps) that isn't really there, in live symphony performances! Growing old is truly not for sissies. Thank you again for your invaluable contributions to the body of knowledge.
Ha Ha - those damn spell "correctors" get all of us, don't they.

I would still put the B "Bee" ipole (I just had an argument with my spell checker) speakers forward of the listening position. Studies have shown that the optimum angle of incidence for maximum envelopment is +/- 60 deg - coincidentally the angle of arrival of side wall reflections in concert halls. Envelopment turns out to be the dominant factor in assessing the quality of concert halls. I experimented with the angle for my first home theater back in 1988 and ended up with the speakers around that angle - it was a music priority system.

However, it was also a 7-channel system - before its time - so I had rears as well. A Lexicon CP-1 (Consumer Product number One) offered a multitude of opportunities to experiment and I did. If at all possible it is advisable to have 7 channels. As shown in my book I had a large "classical" music listening room as well and it was interesting to compare the auditory impressions of the two. The latter room ended up with bipole Mirage M1s generating a very spacious soundstage in the large room. Figures 7.18 and 7.19 in the 3rd edition show the two very different rooms.

Now I have a 9.4.6 channel system in a very different room in California.
Floyd Toole is offline  
post #4913 of 5313 Old 09-16-2019, 09:36 AM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by Soulburner View Post
Dolby spec is 90-110 degrees:

Attachment 2616052

I find I get better envelopment when they are more than 90 degrees (slightly behind) from me. YMMV.
Interesting, and not a problem if you like it. I really think that a 10 deg difference at the side is mighty small - well within localization blur. A 30 deg difference would be more audible. It is interesting that they allow an 80 deg (30 to 110) empty angular window from the fronts to the sides when in real life listening the most important sounds arrive from the frontal hemisphere, including those highly important lateral reflections in concert halls. I have long felt that Dolby had some 'splainin' to do, but they rule the world, so who am I to differ? They are in business, I'm not.

Related to this is the interesting findings shown in section 15.7.1 in the 3rd edition where simplified speaker arrangements are compared to much more elaborate ones (12 and 24 channels) in delivering envelopment. It turns out that the conventional 5.1 arrangement works well, as do several others. Just avoid symmetrical front/back angles. It is important to note that adding a center channel improves envelopment (Figure 15.7). Why? Because in real life there is front arriving direct sound against which to compare later arriving reflections. Stereo has no direct frontal direct sound - it is a phantom image. Yet another compromise presented by stereo.
vavan likes this.
Floyd Toole is offline  
post #4914 of 5313 Old 09-16-2019, 12:05 PM
AVS Forum Special Member
 
Dave in Green's Avatar
 
Join Date: Jan 2014
Location: USA
Posts: 8,354
Mentioned: 152 Post(s)
Tagged: 0 Thread(s)
Quoted: 3787 Post(s)
Liked: 3001
Quote:
Originally Posted by Floyd Toole View Post
... Also seen in the figure is the huge difference between sounds contributing to a phantom stereo center and a real center.

Pity that stereo is the norm
Most everyone here has probably heard the old story about Bell Labs proving in the early 1930s that 3-channel stereo was more effective than 2-channel because an actual center speaker is more effective than the phantom center speaker created in our minds from 2-channel stereo. The main reason 3-channel didn't prevail for home stereo is that vinyl records and phonograph needles could only play 2-channel stereo. It wasn't until digital that >2-channel sound became more common for home stereo recordings. Where 3-channel did catch on was in movies where a center speaker more effectively anchored sounds such as dialog in the center of the big screen.

The reason a really effectively produced phantom center speaker image is so special is because we know there's no speaker there and we're a bit dazzled by how good the illusion is. But even the best center speaker illusion can't match the effectiveness of a true center speaker. A phantom center sound coming equally from L/R speakers is just way different from the same sound coming only from a center speaker as A/B comparisons can easily demonstrate.
Dave in Green is offline  
post #4915 of 5313 Old 09-16-2019, 12:33 PM
Member
 
Floyd Toole's Avatar
 
Join Date: Jun 2017
Location: California
Posts: 836
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 875 Post(s)
Liked: 3076
Quote:
Originally Posted by Dave in Green View Post
Most everyone here has probably heard the old story about Bell Labs proving in the early 1930s that 3-channel stereo was more effective than 2-channel because an actual center speaker is more effective than the phantom center speaker created in our minds from 2-channel stereo. The main reason 3-channel didn't prevail for home stereo is that vinyl records and phonograph needles could only play 2-channel stereo. It wasn't until digital that >2-channel sound became more common for home stereo recordings. Where 3-channel did catch on was in movies where a center speaker more effectively anchored sounds such as dialog in the center of the big screen.

The reason a really effectively produced phantom center speaker image is so special is because we know there's no speaker there and we're a bit dazzled by how good the illusion is. But even the best center speaker illusion can't match the effectiveness of a true center speaker. A phantom center sound coming equally from L/R speakers is just way different from the same sound coming only from a center speaker as A/B comparisons can easily demonstrate.
An addition to your good comment: in movies, the center channel delivers the bulk of on-screen sound, not just dialog. The ventriloquism effect dominates where we think the sound comes from. It is extensively used because panning sounds across the screen adds cost, and makes editing much more difficult, and editing is sometimes done down to hours before release. Only in big budget blockbuster movies is panning much used.

I have annoyed people by getting out of my chair at times to confirm what I just said
Dave in Green and vavan like this.
Floyd Toole is offline  
post #4916 of 5313 Old 09-16-2019, 01:16 PM
AVS Forum Special Member
 
Scotth3886's Avatar
 
Join Date: Jan 2016
Location: New Albany, OH
Posts: 8,226
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 3994 Post(s)
Liked: 2462
Quote:
Originally Posted by Dave in Green View Post
Most everyone here has probably heard the old story about Bell Labs proving in the early 1930s that 3-channel stereo was more effective than 2-channel because an actual center speaker is more effective than the phantom center speaker created in our minds from 2-channel stereo. The main reason 3-channel didn't prevail for home stereo is that vinyl records and phonograph needles could only play 2-channel stereo. It wasn't until digital that >2-channel sound became more common for home stereo recordings. Where 3-channel did catch on was in movies where a center speaker more effectively anchored sounds such as dialog in the center of the big screen.

The reason a really effectively produced phantom center speaker image is so special is because we know there's no speaker there and we're a bit dazzled by how good the illusion is. But even the best center speaker illusion can't match the effectiveness of a true center speaker. A phantom center sound coming equally from L/R speakers is just way different from the same sound coming only from a center speaker as A/B comparisons can easily demonstrate.
A 'center' image may not be coming 'equally' from R and L speaker because the object may not necessarily be in the center.
Scotth3886 is offline  
post #4917 of 5313 Old 09-16-2019, 02:04 PM
AVS Forum Addicted Member
 
Kal Rubinson's Avatar
 
Join Date: Mar 2004
Location: NYC + Connecticut
Posts: 30,286
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 1352 Post(s)
Liked: 1283
Quote:
Originally Posted by Floyd Toole View Post
It is important to note that adding a center channel improves envelopment (Figure 15.7). Why? Because in real life there is front arriving direct sound against which to compare later arriving reflections. Stereo has no direct frontal direct sound - it is a phantom image. Yet another compromise presented by stereo.
Thanks for stating this explicitely, Floyd. I have done demos of stereo vs. multichannel and I usually begin by using one of the RCA Living Stereo SACDs (Reiner's Scheherazade) because so many audiophiles already know it well. After playing the stereo track of the opening movement, I ask the audience to predict how the 3channel track will sound different. Almost universally, they predict there will be more central detail and depth as well as stability compared with the phantom center. Again, almost universally, they are surprised to find that the most obvious consequence of adding the discrete center channel and center speaker is that the soundstage is notably widened beyond the positions of the L/R speakers.
DS-21, Zzzzz..., SDX-LV and 3 others like this.

Kal Rubinson

"Music in the Round"
Senior Contributing Editor, Stereophile
http://www.stereophile.com/category/music-round

Kal Rubinson is offline  
post #4918 of 5313 Old 09-16-2019, 03:11 PM
AVS Forum Special Member
 
Dave in Green's Avatar
 
Join Date: Jan 2014
Location: USA
Posts: 8,354
Mentioned: 152 Post(s)
Tagged: 0 Thread(s)
Quoted: 3787 Post(s)
Liked: 3001
Quote:
Originally Posted by Scotth3886 View Post
A 'center' image may not be coming 'equally' from R and L speaker because the object may not necessarily be in the center.
"Equally" was only used as the extreme example of a perfectly centered object, where 2-channel would struggle the most compared with 3-channel. Off-center objects in 3-channel would result in phantom images between the center speaker and L or R, similar to the phantom center of 2-channel.
Dave in Green is offline  
post #4919 of 5313 Old 09-16-2019, 03:22 PM
AVS Forum Special Member
 
lefthandluke's Avatar
 
Join Date: Aug 2007
Location: Dayton, Ohio
Posts: 1,343
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 181 Post(s)
Liked: 334
I have been running a phantom center since March...I reasoned my speakers image so well in stereo (solid center image giving the impression a center speaker was used) that I decided to forgo a center speaker altogether. I've recently felt something was missing tho. I know why now. Fascinating reading...thanks to all contributing.

at the zenith of his nadir...
lefthandluke is offline  
post #4920 of 5313 Old 09-16-2019, 03:45 PM
AVS Forum Special Member
 
torii's Avatar
 
Join Date: Mar 2015
Posts: 7,234
Mentioned: 54 Post(s)
Tagged: 0 Thread(s)
Quoted: 3589 Post(s)
Liked: 2023
how does "How does electromagnetic induction work in a large audio speaker?"

no idea how this works but have heard this induction can play havoc???

Power: Marantz sr7008, NAD C 275Bee x 2, Video: Oppo 103, Samsung 75un6300
Speakers: Focal aria 948, Focal cc900, Klipsch synergy KSF 10.5, Magnepan LRS
Subs: Rythmik FV25HP, Rythmik FV15HP
torii is online now  
Sponsored Links
Advertisement
 
Reply Speakers

Tags
cea 2034 , double-blind , listening tests , loudspeaker measurements , spinorama



Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off