What makes speakers "disappear " and can it be measured?

[Frgirard]

Thanks

 

[Pdxwayne]

A great bang-for-the-buck question. First, there is good information that a 5 channel system can do an excellent job of replicating the perceived and measured envelopment of 12 and 24 surrounding channels - Section 15.7.1 in the 3rd edition. We also know that achieving truly good bass in small rooms is best done with 2 or 4 subwoofers in specific locations - not those locations that are optimum for the 5 satellite speakers - so why spend money on floor standers that are not as good at low frequencies as "real" subs. Consequently, my answer to your question is none that you suggested, but rather 5 M126Bes and 2 or 4 good subwoofers in a bass managed scheme. I have 7 base-channel speakers, 6 elevated speakers - all of which are high-pass filtered at 80 Hz - and 4 subwoofers in a "Sound Field Managed" (using digital processing in each sub feed) scheme (Section 8.2.8 in the 3rd edition). Simpler, lower cost solutions are possible as described in the same chapter. Multiple subs in one of these arrays can be small because as a group there are significant efficiency gains.

Anyone promoting LPs does not understand, or won't admit, that the signal that is extracted from an LP cannot be the same as the master recording. Cannot = can not! So, such people are content not to hear the art as it was created. This is provable fact, not my opinion. LPs are interesting as historical memorabilia, as are old cars, replicas of old cars, etc., which is absolutely fine - I would love to have an old Chevy to cruise around in on a sunny Sunday morning, but I have zero interest in LPs for enjoying music. Let the flames begin . . .

Dr Toole,
Do you listen to stereo music mostly with multiple speakers and subs?

What do you use for your AVR/processor/amps and what do you use to control the subs?

Thanks!

 

[NTK]

Dr Toole,
Do you listen to stereo music mostly with multiple speakers and subs?

What do you use for your AVR/processor/amps and what do you use to control the subs?

Thanks!

I am not Dr. Toole, but here a full description of his setup.
https://www.thescreeningroomav.com/...te-Real-World-Home-Theater-and-Listening-Room

 

[Kal Rubinson]

Dr Toole,
Do you listen to stereo music mostly with multiple speakers and subs?

What do you use for your AVR/processor/amps and what do you use to control the subs?

Thanks!

I am not Dr. Toole either but I have been fortunate to visit and listen to his system. Yes, he does prefer to listen to stereo music with multiple speakers and subs and, iirc, he uses Auromatic for upmixing.

 

[More Dynamics Please]

@Floyd Toole, I wonder if you could share your thoughts on the relative importance of dynamic performance and how useful it might be to have dynamics properly measured and included in loudspeaker reviews. I included interview quotes from Greg Timbers in the post linked below in which he said he believes that the dynamics required to reproduce live music are not given adequate consideration in most loudspeaker designs and that in his opinion Dynamics will make or break the loudspeaker system:

https://www.audiosciencereview.com/...ewed-powered-monitor.25300/page-7#post-863296

 

[Floyd Toole]

I am not Dr. Toole, but here a full description of his setup.
https://www.thescreeningroomav.com/...te-Real-World-Home-Theater-and-Listening-Room

Thanks for adding this link. Since this was written I have replaced my elderly, and failing, subs with four new Revel B112v2 models. The room as I write is a construction zone, with new flooring, trim and furniture in process of being installed. No acoustical changes were necessary - I have completely adapted to what was there (smile). I had a residual hum/buzz problem and, after much effort, it could only be eliminated by using fully balanced connections throughout. This was traced to a peculiar grounding scheme in the SDP-75 (Trinnov) processor, so I bit the bullet and replaced my old Lexicon (balanced) and new (unbalanced) JBL power amp with balanced input Arcam PA720 units driving the surround and elevation loudspeakers. All now is pristinely quiet and sounding good.

Finally, I removed the two front-wide (+/- 60 deg) loudspeakers. As I said in the earlier description they were unsightly but may have had an acoustical advantage. It turned out that, for me and my programs, they did not add as much to my auditory perceptions as they detracted from my visual impressions of the room. It was my decision, not a WAF, to do away with them. No regrets.

Waiting now for the new kitchen to be done (Covid construction delays persist), the finishing of the cosmetic upgrades in the media room - and time to enjoy it all once more. It is a true pleasure! I like big-screen movies, but really find myself spending more time listening to video concerts. There are now many with full surround, pop and classic (some excellent ones are available streaming), and for me it is high entertainment. The movies sound better than in cinemas, although I look forward to the next season of LA Philharmonic concerts in the beautiful Walt Disney Hall for my "reference" music listening experiences. Just sitting there, listening to the audience enter and the musicians warming up is a heartwarming experience - REAL space! Countless reflections! Massive acoustical interference! Dreadful transfer-function measurements! ALL wonderful! The best sound reproduction can be very rewarding, but it is not the same.

 

[Tangband]

Toole - thank you for inspiring us all .
Hifi and music is great fun.

If you’re in to classical music , I can recommend Netherland Bach society, with outstanding performances on youtube.

 

[Floyd Toole]

@Floyd Toole, I wonder if you could share your thoughts on the relative importance of dynamic performance and how useful it might be to have dynamics properly measured and included in loudspeaker reviews. I included interview quotes from Greg Timbers in the post linked below in which he said he believes that the dynamics required to reproduce live music are not given adequate consideration in most loudspeaker designs and that in his opinion Dynamics will make or break the loudspeaker system:

https://www.audiosciencereview.com/...ewed-powered-monitor.25300/page-7#post-863296

It is of course obvious that limiting dynamic range anywhere in the record/reproduction chain of events will negatively impact the ultimate "realism" of the listening experience. We have no control over the upstream events, so all we can do is attempt to prevent audible degradation in playback. Again, obviously, small cone and dome or horn loudspeakers cannot compete with large cone and dome or horn loudspeakers in terms of their ability to play loud. How loud, though? Loud enough, is the answer, and it should be done without obvious power compression in the loudspeaker drivers or clipping or protective compression/limiting in the amplifiers. Modern home theaters attempt to maintain the cinema sound requirement of peak levels of 105 dB at the listening position. With all channels running in a blockbuster movie audiences in cinemas often find that this is too loud and cinemas turn the volume down (by up to 10 dB) to keep patrons from walking out. In a small home theater these can be, in my terms, abusive sound levels, a hazard to hearing. So how much is enough is a personal thing, having something to do with the condition of one's hearing and the desire to preserve what one has. Hearing loss among musicians and recording engineers is common - it is an occupational hazard that ironically affects how well they are able to do their jobs.

But, back to the story, my LCR speakers were selected not to be limitations to dynamic range - they are large, and at my listening distance easily exceed my limits. I debated between the JBL Pro M2 (a modern "neutral" horn loudspeaker) and the Revel Ultima Salon2 (a large four-way cone dome design). The Revel won the appearance contest. There would be subwoofers, crossed over at 80 Hz, so the loudspeakers would be liberated to play even louder than in their full-bandwidth mode.

Power compression is measurable and always is back in the design stages, but only occasionally is it revealed in specifications or in review measurements. This is useful information, although power compression has a significant time-constant - it takes time for the voice coil to heat up - so it is really difficult to hear. Mechanical or electrical limiting or "clipping" is easily heard and is to be avoided.

I discuss this in the companion website to my current book: www.routledge.com/cw/toole It is open access.

Most music and movies do not challenge the limits to dynamic range, so part of the product selection/decision process is to interrogate one's listening preferences.

 

[rdenney]

...
Power compression is measurable and always is back in the design stages, but only occasionally is it revealed in specifications or in review measurements. This is useful information, although power compression has a significant time-constant - it takes time for the voice coil to heat up - so it is really difficult to hear. Mechanical or electrical limiting or "clipping" is easily heard and is to be avoided.

I discuss this in the companion website to my current book: www.routledge.com/cw/toole It is open access.
...

I have observed likewise, and thank you for validating my observations authoritatively.

When I bought my Revel F12's last year (second-hand, of course--what I was prepared to afford), I searched the web for tests that would help me predict whether they would provide the dynamic punch of my pair of New (well, they were new in 1977) Large Advents driven by two amps. The Advents have lots of issues, of course, but one thing they did and do well is produce a punchy, tight bass.

But I also have a use case that requires loud playing--I play tuba and sometimes like to play along with recordings. The recording has to be loud enough that I can hear the orchestra (as I would if I were on stage) without...holding back. Yes, this is probably abusive, and, yes, I have some hearing loss and tinnitus that can probably be traced back to the time I've spent sitting in front of the tympani. I don't do it often, but I want to be able to do it.

I found that few tests of loudspeakers answer the simple question: How loud will these play? Calculating it from sensitivity and available power assumes linearity that isn't usually there above 100 dB SPL. The reviewers assume that if they are good at 95 dB SPL (for the test tone) they will meet all needs. Maybe their lawyers are afraid they'll be sued for promoting hearing loss.

But the F12's were reviewed by Soundstage and they showed test results from the NRC. Those results included linearity tests at 100 dB, with the added these sentences:

"Our standard is to provide the THD+N measurement at 90dB with a measuring distance of 2 meters (within the anechoic chamber). Since this speaker produced very low distortion levels under those conditions, we have added a second measurement performed at 95dB to give an indication of performance under higher-output conditions. In addition, we have also provide an additional Deviation from Linearity measurement at 100dB based on the good performance at 95dB."

No other speaker received such treatment, except (as I recall without looking back) the Salon 2. That paragraph (and the measurements that resulted) were a significant factor in deciding to buy them.

When I bought them, I rearranged my listening room to take advantage of them. The speakers now indeed disappear (to reference back to the OP's title). But there is some boominess in the bass--a little loss of tightness in the 80-150 Hz range as it seems to me so far--and I haven't yet worked my way to that chapter

I always found myself sitting near the back row of the mezzanine for orchestra concerts, but that was for the same reason that I bought the F12's second-hand. Those first three rows fetch the highest price. But I also like looking down on the orchestra, and want to keep my eye on what the tuba player is up to.

Rick "most recently played the Bruckner 7 along with the SLSO--when the wife was not at home" Denney

 

[Wes]

I had to dispute that statement to convince the (then) publisher to let me publish my (erstwhile) column, Music in the Round and I continue to review multichannel products. Unfortunately, most of the reviewers are less enthusiastic about multichannel than I am.

more source material would generate more enthusiasm

"history often shows us that technological superiority is not enough" - Dr. Betamax

 

[Wes]

Dr. Toole,

Since you have not yet gone on vacation (from this) forum, I wonder if you would comment on panel speakers such as electrostatics and Magneplanars?

... particularly with respect to SpinoRama results compared to subjective listening experiences for them

 

[Floyd Toole]

Dr. Toole,

Since you have not yet gone on vacation (form this) forum, I wonder if you would comment on panel speakers such as electrostatics and Magneplanars?

... particularly with respect to SpinoRama results compared to subjective listening experiences for them

They are just different transducers - different ways of moving air. The diaphragms cannot move very far so to generate adequate sound levels at lower frequencies they need to be large. This makes them directional, especially at higher frequencies. They cannot be enclosed, so they are inherently dipoles, which is a characteristic, not a defect. The diaphragms are very light membranes because the motive forces are not as high as the powerful linear motors in moving-coil transducers. This fact has led a lot of people to think that they can move more quickly, reveal more detail, etc. than "conventional" cones and domes. This is not the case. They also allude to more "open" sound, lacking "boxiness". This also is fantasy.

Conventional anechoic measurements are capable of revealing how such speakers can sound, and there are good and less good examples of the breed. One can easily find examples of panel loudspeakers with audible resonances, disruptive directivity characteristics, limited power handling capability, and so on. In the 3rd edition Figure , Figure 18.1(c) shows a Quad ESL Mark 1, 7.12 shows data on a Quad ESL 63, Figure 18.7(a) shows a Magnaplanar 3.6. The 1st and 2nd editions show a Martin Logan Prodigy as Speaker M in Figure 18.4. In every case the results of double-blind listening tests revealed evidence of what the measurements show.

 

[MattHooper]

I'm thoroughly enjoying Prof Toole's posts, as usual!

The "bunch of seats and people" do indeed corrupt a well organized floor reflection from the audience floor - but not the stage floor. The same seats and people do however create a strong and audible "seat dip effect" - a fairly wide and deep dip in the frequency response around 100-200 Hz. Which one is worse? I wonder. But my favorite seats have been within the first 3 rows of the front balcony, mezzanine, terrace (whatever the first elevated level is called) where the seat dip effect has not been able to develop. Perfection is hard to find. I also like the experience of looking slightly down on the orchestra.

I used to attend the symphony regularly and have sat in all sorts of different seats, from balcony, back of the 1st floor, middle etc. But I always favored sitting on the main floor, right up close to the orchestra. While plenty of people favor the mixing/blending and tonal quality of a symphony heard from further back in a hall, I favor immersion and vivid instrumental timbre and texture. Which I would get up close.

For the same reason, I tend to favor speakers that can produce more of that sensation, and also orchestral recordings that may be more obviously closely mic'd (which I know plenty of classical music aficionados deplore). For instance I adore the sonic qualities of many of the Bernard Herrmann soundtracks, which tend to have closely mic'd sounding up front instruments that have tons of presence.

Another thing: while a mere pair of stereo floor standing speakers are clearly inadequate in producing truly realistic sound of an orchestra, I'm frankly amazed at how close they can get, with a dollop of imagination added in. I've recently re-arranged my seating a bit and the "speakers dissapearing" and width and depth of the soundscape is just enormous, with sounds like "back of the orchestra instruments" sounding truly far away. But of course it's not really to the ginormous scale of a real orchestra, not the same spread, so I notice if I just make a little adjustment to my thinking, eyes closed, I imagine I'm listening to the orchestra from up in the balcony further away. Assuming that perspective makes the scale actually seems more believable, and the sense of realism seems to be heightened for me.

 

[MattHooper]

We actually do listen with our body and feet as well. So if you have a non-solid floor (won't work with say concrete), removing your own feet from the floor may actually have a similar effect as your spring-based pods. You may get an impression of cleaned up sound and attentuated bass. It's quite fascinating

Interesting idea!

Certainly part of what I presumed I'm talking about is the vibration of the speakers getting to me. Though as it happens I never have my feet directly on the floor. When listening I'm on a huge thickly stuffed sofa with a deep seat, so often I'm either curled up on the seat, or my legs are on a plush ottoman. So the differences I'm hearing with and without springs isn't due to my feet being on the floor.

What if I managed to put my whole listening sofa on decoupling springs? Interesting thought experiment, though I'm a bit skeptical it would result in exactly the same qualities from the bass to the high frequencies, as with the speaker. When the speaker is sitting on the floor playing loud bass heavy music, I can very clearly feel the floor vibrating around the speaker. With the springs underneath, that vibration is gone. I suspect some level of vibration/feedback happening between the floor and speaker that is at least partially causing the slight blurring of sound. But...I dunno.

 

[Kal Rubinson]

more source material would generate more enthusiasm

Agreed but I still acquire/download a couple of new ones each week.

 

[Wes]

I suppose you could start an advocacy group called '5chan' but that might create confusion...

 

[Matthew J Poes]

Quantum Logic is a totally different process intended to construct "new" listening experiences, not to subtly enhance stereo. Dr. David Griesinger, the brains and good judgment behind the original Logic 7 is retired. I know nothing about the current offerings - I too am retired.

david and I have talked at length about this. He feels a good intentioned engineer likely misunderstood his original process and has since forever corrupted it beyond recognition. He told me that both “Logic 7” and the newer Logic 16 of devices made over the last 10-15 years are not reflective of his original intent. In fact the transition happened when Lexicon modified the surround processor they had at the time to include HDMI. Logic 7 was apparently reprogrammed for the new hardware and fundamentally changed. It’s too bad.

 

[Floyd Toole]

david and I have talked at length about this. He feels a good intentioned engineer likely misunderstood his original process and has since forever corrupted it beyond recognition. He told me that both “Logic 7” and the newer Logic 16 of devices made over the last 10-15 years are not reflective of his original intent. In fact the transition happened when Lexicon modified the surround processor they had at the time to include HDMI. Logic 7 was apparently reprogrammed for the new hardware and fundamentally changed. It’s too bad.

Yes, even a quick listen is enough to tell one that what is now promoted as Logic 7 is not the same, or even a sensible development, of the original. It is a pity that they didn't change the name, but instead used the good reputation of the early Griesinger designs to sell something different.

 

[Matthew J Poes]

My experiience with too much absorption is howewver negative. Adding it at the spekaer wall side in moderate amount gives to me higher dynamics and quiteness in silent parts. Also, there is an feeling of needing more amplifier power, and to turn up the volume. The rest of the room has no special treatment. It sounds fine by me.

im using your post to make a point, these comments are to agree with what you say.

An anechoic listening room has no spatial reinforcement. all spatial cues would have to come from the speakers. 2-channel playback is fundamentally missing those cues and could not possibly present the spatial environment of the original musical event. That may be useful in applying a microscope to the music for editing purposes but is not a useful way to listen to music.

such environments could be good for surround sound. A surround system can reproduce spatial cues far more accurately than the room can mimic it. Stereo reproduction with 2 speakers is just an illusion of the real thing and not a very good one.

I had talked to Floyd about this and at one time advocated for making multichannel dedicated spaces very dead. Floyd pointed out that our brain is very adaptable to environments. In this case, when the brain is faced with cues from both a large and small acoustical space, he noted the brain tends to ignore the cues of the smaller space. Meaning when we get signals from the walls (small room cues) and signals from the speakers (meaning large room cues) our brain will tune out those room reflections and presume it is in the larger space. A great trick for not really requiring a dead room.

Sean Olive pointed out to me that it’s rare people only ever listen to multichannel. So while my approach to designing more dead multichannel rooms to avoid distractions from the small room might work well for surround, it would be a lousy room for two channel. Since the more appropriately treated room retaining some meaningful reflections will largely be ignored with multichannel, it makes more sense to design all rooms to retain some amount of reflections.

which is all to say, in average rooms it often makes sense to just leave them alone. Good speakers make a far bigger improvement than the room itself ever will. Absorbing all the reflections is counter-productive. It destroys the sense of spaciousness.

that doesn’t mean treatments have no place. Dedicated rooms are, for example, anything but average spaces. They have no natural sources of diffusion or absorption. You need to add it. In the last year alone I have been asked to make residential rooms sound good which had RT60 times from 2-3 seconds. These were fully furnished rooms. My first fix was to ensure they had good speakers. The second fix was really just about getting the decay time down to something reasonable and so absorption was added. But not at first reflection points. I wasn’t trying to remove reflections. I was simply trying to help the sound decay faster to avoid the overwhelming reverberant sound. In most of these rooms I add diffusion. It has some real advantages when used correctly and when you have nothing else in the room to break of reflections, you have to add it.

 

[Matthew J Poes]

It is of course obvious that limiting dynamic range anywhere in the record/reproduction chain of events will negatively impact the ultimate "realism" of the listening experience. We have no control over the upstream events, so all we can do is attempt to prevent audible degradation in playback. Again, obviously, small cone and dome or horn loudspeakers cannot compete with large cone and dome or horn loudspeakers in terms of their ability to play loud. How loud, though? Loud enough, is the answer, and it should be done without obvious power compression in the loudspeaker drivers or clipping or protective compression/limiting in the amplifiers. Modern home theaters attempt to maintain the cinema sound requirement of peak levels of 105 dB at the listening position. With all channels running in a blockbuster movie audiences in cinemas often find that this is too loud and cinemas turn the volume down (by up to 10 dB) to keep patrons from walking out. In a small home theater these can be, in my terms, abusive sound levels, a hazard to hearing. So how much is enough is a personal thing, having something to do with the condition of one's hearing and the desire to preserve what one has. Hearing loss among musicians and recording engineers is common - it is an occupational hazard that ironically affects how well they are able to do their jobs.

But, back to the story, my LCR speakers were selected not to be limitations to dynamic range - they are large, and at my listening distance easily exceed my limits. I debated between the JBL Pro M2 (a modern "neutral" horn loudspeaker) and the Revel Ultima Salon2 (a large four-way cone dome design). The Revel won the appearance contest. There would be subwoofers, crossed over at 80 Hz, so the loudspeakers would be liberated to play even louder than in their full-bandwidth mode.

Power compression is measurable and always is back in the design stages, but only occasionally is it revealed in specifications or in review measurements. This is useful information, although power compression has a significant time-constant - it takes time for the voice coil to heat up - so it is really difficult to hear. Mechanical or electrical limiting or "clipping" is easily heard and is to be avoided.

I discuss this in the companion website to my current book: www.routledge.com/cw/toole It is open access.

Most music and movies do not challenge the limits to dynamic range, so part of the product selection/decision process is to interrogate one's listening preferences.

I’ve built a reputation of apparently liking things louder than most. For me, it adds to the perception of realism. It’s a scale issue. I find that the performance feels less real when the dynamics and output aren’t there.

when I moved to designing rooms professionally I began strongly advocating for building the spaces to be quieter. While we can hear down into the noise floor, it doesn’t change the fact that if the noise floor is much lower then we can listen at a quieter level and still resolve those fine details. I also find it relaxing sometimes to have a very quiet place to retreat to.

in any case, meeting the dynamic needs of modern movies has become more challenging. I began selling a line of speakers, Perlisten, because it’s one of the few that can really get to the levels needed to achieve reference level output in larger rooms. Houses and rooms are getting bigger. While I haven’t designed residential home listening rooms and theaters for decades, at least In the last decade I have found a shift in the size of rooms I am working with. Where 1500 to 3000 cubic feet was quite common. This year I have designed spaces that were 5500, 7500, 13,000, even a 24,000 cubic foot space. People are building some crazy houses! Such large volumes require larger speakers and scaling speakers often comes with challenges and compromises.

You Can imagine in such commercial scale spaces i also can’t get away with what typically works in normal residential spaces.