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

[Jim Matthews]

We had exactly the same shag carpet in our living room back in the 60's, but wall to wall!

This one is bespoke Hemp fiber woven by Vegan druids named Madge.

 

[Duke]

View attachment 144624
Pizza crumbs optional.

While you were out I ate a bag of Cheetos while sitting on your carpet and I bet you didn't even notice.

 

[dualazmak]

Scanned through this thread and I did not see any reference to the precise matching of right and left channels/speakers. I've found any variation causes the image to wander and the "holographic" effect collapses.

Yes, I agree with you that your point is another critical factor.

For this, I usually use the track-2 "Phase Check" and track-3 "Five location Positioning Check by Dram Solo" of "Sony Super Audio Check CD"; I carefully check and fine tune the relative L-to-R balance for each of the SP drivers separately, i.e., L & R sub-woofers, woofers, midrange squawkers, tweeters and super tweeters, and then of course with all the SP drivers singing together.

I also check the L-to-R sound similarity/identicality, or I can say "frequency balance", for each of the drivers separately by using track-11 "white noise" and also track-12 "pink noise". Even tough this test is subjective ear listning one, I always find it is very nice and helpful for excellent L-to-R "sound balance".

Let me add one more point, please.

In my multichannel multi-driver (multi-way) multi-amplifier project, I found that the positioning/alignment of the L & R super tweeters, which dedicatedly and directly (with no LC-network nor attenuators) driven by an amplifier, effectively contributes to the "disappearance of SPs"; for the details please refer to my specific post here on this.

As wrote in my above post #86, so many critical factors should be simultaneously achieved for "excellent disappearance" of our SPs, I believe.

 

[Jim Matthews]

While you were out I ate a bag of Cheetos while sitting on your carpet and I bet you didn't even notice.

The dogs did.

 

[ferrellms]

I'm a little surprised no one has mentioned a lack of resonances. That is one of the most important qualities for a speaker to avoid revealing itself as a wooden/metal/plastic box. It modifies timbre, can make a note stand out in the time domain, and just sticks out like a sore thumb.

Directivity is important for sure when it comes to the spatial presentation aspect, and I find wider directivity speakers are usually a bit more likely to have this disappearing effect, but having minimally audible resonances is paramount.

Per toole:

"If resonances exist in loudspeakers, either in the transducers or in the enclosures, they are added to those in the program, changing the timbre. These changes are monotonously added to all reproduced sounds: voices, musical instruments and so forth."

Furthermore, these resonances actually become more audible in a reflective environment, not less as some might assume. You're less likely to hear a resonance in, say, a nearfield setup with ample room treatment than you are in a typical living room:

"An interesting fact is that reflected sounds are perceived as “repetitions” of the direct sound, and the result of the accumulated “looks” at the sound is that low- and medium Q resonances become more audible. Consequently two contrasting events follow: flaws in loudspeakers are more obvious (bad), and subtle timbral cues in music are better revealed (good) (Toole and Olive, 1988). Listening through headphones or in a dominant direct sound field (a dead room) make us less sensitive to low- and middle-Q resonances, possibly explaining why some headphones with unimpressive measurements are tolerable, at least with pop music."

Edit: All from chapter 4 of Toole's book.

Floyd Toole hasn't heard Kii 3, Dutch Dutch, Beolab. Sean Olive does not work for any of these companies, but their competitor. They have not really kept up with state of the art, ie., cardioid speakers. Their listening evaluation recommendations are not very challenging (no EDM). Maybe time for some newer thinking on what makes a good speaker?

Floyd Toole is a reference, but time moves on. I cannot accept a lot of what he says given my own meager experience and prejudices, as it is based on long ago listening panels (repeatable?, newer stuff maybe?) And yes, I read his book, and saw the picture of his system, which would now be considered mediocre, at best.

 

[richard12511]

Floyd Toole hasn't heard Kii 3, Dutch Dutch, Beolab. Sean Olive does not work for any of these companies, but their competitor. They have not really kept up with state of the art, ie., cardioid speakers. Their listening evaluation recommendations are not very challenging (no EDM). Maybe time for some newer thinking on what makes a good speaker?

Floyd Toole is a reference, but time moves on. I cannot accept a lot of what he says given my own meager experience and prejudices, as it is based on long ago listening panels (repeatable?, newer stuff maybe?) And yes, I read his book, and saw the picture of his system, which would now be considered mediocre, at best.

Salon2 Auro3D system is mediocre???

 

[napilopez]

Floyd Toole hasn't heard Kii 3, Dutch Dutch, Beolab. Sean Olive does not work for any of these companies, but their competitor. They have not really kept up with state of the art, ie., cardioid speakers. Their listening evaluation recommendations are not very challenging (no EDM). Maybe time for some newer thinking on what makes a good speaker?

Floyd Toole is a reference, but time moves on. I cannot accept a lot of what he says given my own meager experience and prejudices, as it is based on long ago listening panels (repeatable?, newer stuff maybe?) And yes, I read his book, and saw the picture of his system, which would now be considered mediocre, at best.

What? There are many things wrong with this post:

• What does this have to do with anything?
• Who says cardioid speakers are not in line with the various findings summarized in Toole's book?
• The three speakers you listed follow exactly the principles described in his book? Flat-ish on-axis, smooth directivity, minimized resonances. I've heard two of the three you've mentioned.
• The D&D 8C's designer has explicitly said he designed the 8C based on the principles in Toole's book.
• The listening system in the book cannot reasonably called mediocre. More people should use multichannel setups.
• The primary benefit to cardioid speakers is tidying up the bass and lower mids, which is very cool, but can ultimately be achieved with multiple subs and proper room EQ as well.
• Harman has designed speakers of theoretically similar caliber of directivity control, see Lexicon SL-1.
• The research Toole, Olive, etc have done doesn't really have anything to do with the speakers the company ultimately decide to release.
• Some of the listening tests are old, but that doesn't stop the results from being valid, especially when they've been repeated multiple times over decades of research, not just from Harman. Science always moves forward but you can't just throw out the old stuff without evidence of something better.
• What does any of the above have to do with my post you quoted?

If my post prompted that response from you, I get the impression you didn't read his book well enough.

 

[Thomas_A]

A coffe table can be good because, as you say, they block the first reflections from the floor reaching your ears.
A coffe table can be bad if there is no damping material on the table. Without a table-cloth theres gonna be lots of reflections at high frequencies and if they are within 5 ms from the direct sound from the loudspeaker reaching your ears, you get ugly colorations . Early reflections in the treble area are especially bad for sound quality.

But again, the reflections need to reach your ears. Primary reflections can be seen by using mirrors. I don't see my speaker drivers while having a mirror on the coffee table.

 

[Duke]

But again, the reflections need to reach your ears. Primary reflections can be seen by using mirrors. I don't see my speaker drivers while having a mirror on the coffee table.

Good point. A coffee table can be positioned to intercept the floor-bounce notch without becoming itself a primary reflection surface. This is how Earl Geddes uses a coffee table in his purpose-built listening/home theater room. He also has large vertical "slats" running side-to-side on the ceiling which break up the ceiling bounce. I would have never realized that the coffee table or the ceiling slats were acoustic treatment if he hadn't told me.

 

[Thomas_A]

There is direct evidence that floor reflections help us localize speakers:

Auditory localization: effects of reflecting surfaces:
https://pubmed.ncbi.nlm.nih.gov/2130378/


So if you want a speaker to disappear to the greatest extent possible, you'll want to reduce that reflection. I anticipate Toole commenting that the floor reflection sounds "natural", and that we probably appreciate the impact it has on spectral balance. I'd suggest reducing the floor reflection and using EQ to obtain the desired spectral balance, which may not be completely flat on axis.

In addition, there is evidence that the ratio of forward to lateral sound is important for our perception of envelopment. Floor and ceiling reflections re-enforce the forward sound. In stereo, the major components of the forward sound are the direct sound, floor reflection, the ceiling reflection, and the front-wall reflection. The sidewall reflections (ideally delayed more than 5ms) constitute the lateral sound. By reducing the floor, ceiling, and front wall reflections, we decrease the ratio of forward to lateral sound, improving our perception of envelopment. This also increases the apparent soundstage width. Again, this may require deviating from the standard of flat on axis sound to some degree. Another way of improving the forward to lateral sound ratio is by exaggerating the sidewall reflections or supplementing them with additional speakers. It's my opinion that this approach has a negative effect on clarity when compared to the approach of reducing floor, ceiling, and front wall reflections.

It appears from the abstract that the ceiling had a negative effect on localisation; only the floor had a significant positive effect on especially height localisation. Which again suggests that a properly placed coffee table that blocks the floor reflection without adding new ones would decrease this localisation effect. Normally however, the floor bounce is there when some auditory event occurs in front of you. Either in real life or in the recording. Difference is however that the recording does not include the various angles. It will only relate to the height of the speakers.

 

[dualazmak]

Coffee table,,, interesting discussion.

So how do you see and think about my listening environment with carpet, coffee table and PC monitor on the carpet?

The ceiling is covered by microporous diatom panels carefully selected with proper sound absorption performance.

In this multichannel multi-driver multi-way multi-amplifier system, now the SPs always disappear quite nicely under the latest system configurations...

 

[Thomas_A]

Coffee table,,, interesting discussion.

So how do you see and think about my listening environment with carpet, coffee table and PC monitor on the carpet?
View attachment 144916

View attachment 144917

The ceiling is covered by microporous diatom panels carefully selected with proper sound absorption performance.

In this multichannel multi-driver multi-way multi-amplifier system, now the SPs always disappear quite nicely under the latest system configurations...

If you have a mirror, you could visualise your primary reflections from the speakers. Are they hidden by the table?

 

[dualazmak]

I have no mirror under the table... How and what can you suggest? I have 30 x 40 cm portable mirror in my office upstairs.

I almost got your point. I will place a mirror at the position of the coffee table, and check if I can see the SPs in the mirror, that's right?

 

[Thomas_A]

I have no mirror under the table... How and what can you suggest? I have 30 x 40 cm portable mirror in my office upstairs.

Try it.

 

[dualazmak]

Just did it. I can see the SPs in the mirror when I place the mirror at my current PC monitor position. Later-on, I will push my coffee table to that position to check if I would have better sound perspectives (better SP disappearance) or not...

 

[JWAmerica]

A properly placed coffee table (or ottoman as others have mentioned) can be an effective trap, especially when combined with thick carpet.

 

[dualazmak]

A properly placed coffee table (or ottoman as others have mentioned) can be an effective trap, especially when combined with thick carpet.

Yes, I carefully looked again my current setup;

My usual ear height during intensive listening session is about 50 cm lower than the camera lens height of Photo-03 above, and the mirror position reflecting SPs from my eyes is at the PC monitor's leg position on the carpet in Photo-04.

Consequently, the coffee table in front of me is always fully blocking my sights to the leg of the PC monitor, i.e. the floor reflection point from the SPs! Furthermore, I have nice carpet between myself and the SPs, and also I have the ceiling covered by microporous diatom panels.

At least in terms of "coffee table and carpet", it looks that I have already established almost ideal setup for "excellent disappearance" of SPs...

 

[Doodski]

Yes, I carefully looked again my current setup;
View attachment 144958

My usual ear height in listening session is about 50 cm lower than the camera lens height of Photo-03 above, and the mirror position reflecting SPs from my eyes is at the PC monitor's leg position on the carpet.

Consequently, the coffee table in front of me is always fully blocking my sights to the leg of the PC monitor, i.e. the floor reflection point from the SPs! Furthermore, I have nice carpet between myself and the SPs, and also I have the ceiling covered by microporous diatom panels.

At least in terms of "coffee table and carpet", it looks that I have already established almost ideal setup for "excellent disappearance" of SPs...

I don't remember you having such large subwoofers. What are those things beneath the Yamaha speakers?

 

[dualazmak]

I don't remember you having such large subwoofers. What are those things beneath the Yamaha speakers?

Thank you for your continuing attention on my project. You would please visit my post here for the physical alignment of the SPs!
The large L&R sub-woofers are Yamaha YST-SW1000.

Please refer to my most recent total Fq response in my post here.

 

[Doodski]

Thank you for your continuing attention on my project. You would please visit my post here for the physical alignment of the SPs!
The large L&R sub-woofers are Yamaha YST-SW1000.

Please refer to my most recent total Fq response in my post here.

A fun and wonderful system. I always enjoy seeing it and reading about it.