Speaker Testing: why mono is better

[amirm]

First, I offered no belief (pro or con) to have faith in.

Sure did. You question the research with no research whatsoever on your side as to why you have a valid point. To the extent you are sticking to such argument, then you put your belief and gut feelings above research.

It is part of science to not agree with methodology or its shortcomings.

There is no such science. What you are doing is just arguing. By your notion, everyone's disagreement with research becomes "science" by itself. This is quite absurd. If you are not a peer of the science being presented, or don't have relative research of such to present, then you have a random opinion about something. The word science doesn't even enter the vocabulary.

 

[Racheski]

We always listen stereo and the masking of defects is a good thing: you may potentially have a subjectively good sounding speaker with inferior or flawed specs, so potentially cheaper.

I can see the point here. Imagine a scenario where a cheap speaker sounds like crap in mono, but in stereo it sounds good, or at least on par with more expensive speakers. E.g., Although we don't know the price of speaker "E" in the paper, its spatial quality went from 2nd to 1st after changing from mono to stereo, respectively. Even if this is the phenomena where "listeners get...lost in the content in stereo", as a consumer should I care? If I have to choose between a cheap speaker whose flaws are obvious in mono, but said flaws are inaudible in stereo (for whatever reason) vs. a more expensive speaker that sounds better in mono, but has similar SQ to the cheap one in stereo, we pick the cheap one, right?

 

[Inner Space]

I'm old enough to remember when mono was all a lot of people had. Some by choice. My great-uncle had a 9-cu-ft reflex cabinet in the corner, built of brick, like a supplementary fireplace. He and my great-aunt sat before it, ranged in armchairs. It was wonderful. So obviously a great speaker can be conceived in mono, and designed, built and used in mono. Nothing about adding a matched second can tell us more than we already know - except one thing, I think.

What we now enjoy about stereo imaging depends on close pair matching and absence of "cabinet talk", which spreads and bloats an image at unpredictable pitches. But back then it didn't matter so much. A faint woody hum from a cabinet made a clarinet sound better. Now it pulls what should be floating free back toward the cabinets, in a weird mustache shape.

Does testing of single-unit speakers take the issue into account? At the moment it's not clear.

 

[JSmith]

There is only one way to listen in mono;

JSmith

 

[Sean Crees]

I have a small bedroom where my sitting position won't always be in the same place. Sometimes i'll be at the desk in a chair, but other times i'll want to listen while sitting or laying in bed or just walking around the room. Would it sound better in all locations with a single speaker in mono in the corner of the room instead of 2 speakers sitting on the desk in the normal configuration? If i had a budget for speakers, would it be better to spend twice as much for a single speaker instead of half as much for two speakers?

Say 2x Adam T5V's or 1x Neumann KH80 DSP?

 

[pma]

No preference for one speaker sound on my side. I want to listen even the monophonic recordings through two speakers.

 

[boselover61]

First post, so feel free to ignore me...

While I understand Amir's point and I am far from rejecting his explanation, I don't see how this is of any relevance at all but for logistics.
We always listen stereo and the masking of defects is a good thing: you may potentially have a subjectively good sounding speaker with inferior or flawed specs, so potentially cheaper.

I don't get it. What's so hard to understand. Let me put this in easy to understand words

2 bad speakers in stereo= maybe ok sound

2 very good speakers in stereo = very good sound

We use mono listen test to determine if one singular speaker is good. If one is good enough why wouldn't a stereo setting be very good?

That's just easy logic.

 

[Racheski]

This is the scenario:
2 bad speakers in stereo= good sound
2 good speakers in stereo = good sound

Bad speakers are $2000 less than good speakers.

Wut do?

 

[boselover61]

This is the scenario:
2 bad speakers in stereo= good sound
2 good speakers in stereo = good sound

Bad speakers are $2000 less than good speakers.

Wut do?

Sell the good speaker and keep the bad speakers if they sound the same to you? Just use phone speaker at that point

 

[Blumlein 88]

This is the scenario:
2 bad speakers in stereo= good sound
2 good speakers in stereo = good sound

Bad speakers are $2000 less than good speakers.

Wut do?

Sell two good speakers and by 5 more bad speakers and have 7 channel surround.

 

[boselover61]

Sell two good speakers and by 5 more bad speakers and have 7 channel surround.

Hey guys check out my speakers!!!! Amazing sound stage dolby atmos dts stereo x dirac audyssyey audiophile audioquest 3d 4d 30.11 speakers great imaging details like angels descending from heaven

Ps: its not my setup i just found it online

 

[spacevector]

Many thanks for opening up discussion on this very interesting topic amir.

I want to share a recent experience as a shit-ear audiophile. I started comparing a couple speakers at my desk. Placed one speaker of each make where my LR would go normally - about 4ft away from me.

When listening in mono, it was somewhat easy to compare the tonality. Also, there was this sensation of the sound being rather closed in on one speaker and more open on the other - almost as if the sound was coming from a larger general area.

Then I switched to stereo with these speakers of different makes comprising my stereo pair. To my surprise (and shame), it sounded fine. I could 'see' the center image just fine and the music didn't sound odd.

May be I just got lucky with this pair, but to me it seems like stereo is the great equalizer - capable of applying copious lipstick on our pigs.

 

[boswell]

I am sorry, I gave up reading all the posts after the second page. In absolute terms, the tests are to evaluate how well the speaker produces sound. They are not about listening to them. How people listen is irrelevant to the tests. Of course a good testing speaker would be expected to be a good listening speaker ( however it is used) or the converse. That is why the speaker is tested, the sound it makes, not the listening to to it.

 

[StevenEleven]

It's a decent and interesting point, IMHO, and backed by research in Toole's book. Stereo and even moreso multichannel tends to smush (technical term) together differences in the perception of speaker quality as compared to mono listening.

However, it only serves to emphasize that listening tests are most efficiently and reliably done in mono if you want to ascertain differences in preference and quality of speakers, which is what @amirm is trying to do here.

You can make adjustments for smushing effect and adjust for stereo and multichannel budget as desired. This thread has some nice graphical information to help someone ballpark it. In terms of preference ratings, for example, two 6s (~decent) in stereo might not be that far off at all from two 7s (~very good) in stereo, once you account for listening in stereo (or multichannel).

Another thing I remember from parsing out the data once is that the preference rating formula tends to under-rate speakers on the high end of the scale. That is, a 7.5 or eight by formula might well rate something higher than an eight in a real subjective double-blind listening test. Also on double blind listening tests the highly performing speakers tend to wind up in a statistical tie, IIRC. FWIW & etc.

 

[boswell]

oops one too many to's

 

[Racheski]

Sell two good speakers and by 5 more bad speakers and have 7 channel surround.

Touche

 

[Mnyb]

I think you raised a very good point about stereo testing: there is no standardized way to set up a test for stereo listening. This leads to the conclusion that current reviews in stereo are at best a crapshoot - some may be good some may be inaccurate. This reduces the value of stereo reviews - although not eliminating it completely, you are now left wondering how much of the review is about the room interaction and how much is the pure speaker? I just believe the heuristic for speaker performance is much more predictive with mono testing than stereo testing. I'm not saying that stereo does not offer unique performance measures that should be investigated but I do not believe it would contradict the conclusions of a mono review.

Yes as Amir states in the video It will be :

Content dependent.

Room dependent.

Setup dependent. ( speaker placement ).

I think we are little bit fooled by all the reviews and our own sighted assessment about stereo imaging. It plays a big very role in the folklore about Hifi.

But in the end why would not speaker found to have good tonality and good dispersion and low distortion also be good in any configuration for example 2ch stereo ?
What property could such speaker have that ruined its 2ch performance ? None I think . So the Stereo performance is a given if you place it properly in your room and have a good room.

If a reviewer test it . I think Spocko is right , we will get a review of the reviewers room and speaker placement not the purely speaker. I think Amir says something about exactly this in the video .

In short to many uncontrolled variables . Amir is one person speed testing speakers I'm sure you can get the last 1% by spending 500% more time on every review . I think it works better as "market survey" Speakers are a kind of last frontier where anything goes , haven't we all heard and seen so many downright strange speakers ?

The Hobby in the whole is served better this way .
If there is consistency in speaker performance for both amateurs and pros we diminish the circle of confusion over time.

 

[KSTR]

When you say a linear phase speaker, what does that mean? If you're talking about multiway speakers with noncoincident drivers (like your designs, as far as I know), phase can only ever be linear relative to one position with a speaker. A speaker designed for linear response on axis will not be linear elsewhere. If I'm wrong please correct me.

From what I know, under anechoic conditions, 60 degrees of phase shift within one critical band is considered audible. In rooms, I don't think your working hypothesis holds when you start adding the effects of reflections. The phase error in the loudspeaker would have to be extremely gross. John Vanderkooy did a study that showed little audibility for shifts adding up to several cycles. If you also account for the fusion interval for localization, which is measured in tens of milliseconds, and then phase locking for bass taking upwards of 200ms, phase doesn't really enter the picture other than when comparing an ideal situation to a typically measured one.

Regarding the topic at hand generally: a paper by Earl Vickers: https://www.sfxmachine.com/docs/FixingThePhantomCenter.pdf

The point is: comparing a minphase speaker with its linphase version is effectively comparing different source materials, not technically different speakers, as the phase unwrapping can be thought of as being applied globally on the input data. Therefore, it does not matter much if the speaker "falls apart" off-axis or significant room effects add in, all this just comes on top of the input signal we did change. Of course you can make the room response so bad that it drowns everything else (think a technical reverberation room used for acoustic measurement).

This (effect of phase response) is by the way a topic that nowadays everbody can precisily evaluate for themselves as all the necessary means are available at low, even zero cost and doing long term proper ABX is really dead simple. The only prerequisite is that you must start with a linear phase speaker, even a simple test speaker with a decent fullrange driver is enough.
In my view, any real audiophile should use DRC anyway (othwerise you really miss a lot of potential) and it is very simple to switch the active convolution kernel for linphase correction to a minphase version.
It's all out on the table, just pick it up. There is close to no money in making rigorous studies -- this applies to many audio-related topics -- so we have to make them ourselves rather than wait (maybe forever) until someone else may finally do it.

 

[rxp]

Headphones are actually more complex to test for because of visual/fit cues. But a simulator headphone is better for testing that because you get no cues from the physical structure of the headphone and delays in switching.

I can see the point here. Imagine a scenario where a cheap speaker sounds like crap in mono, but in stereo it sounds good, or at least on par with more expensive speakers. E.g., Although we don't know the price of speaker "E" in the paper, its spatial quality went from 2nd to 1st after changing from mono to stereo, respectively. Even if this is the phenomena where "listeners get...lost in the content in stereo", as a consumer should I care? If I have to choose between a cheap speaker whose flaws are obvious in mono, but said flaws are inaudible in stereo (for whatever reason) vs. a more expensive speaker that sounds better in mono, but has similar SQ to the cheap one in stereo, we pick the cheap one, right?

Exactly! And that's why this is such a nice hobby. Most people just get a level of good and that's it, they can't discern anything else which is completely normal. Obsessing over flat frequency response and what corresponds to what the research shows is a good speaker is a waste of time for the majority. For us hobbyists it's cool - but I struggle too. That's why the speakers I purchased over the last 3 years (R300s, LS50s and R100's) in a multi channel setup will be it for decades.

And Amir's video on the research shows me exactly why - I ALWAYS listen to in multi channe since my dad got a surround system in 1995 when I was 11 and one in his car when I was 13. I upmix all my music, even on headphones (speaker virtualization). No wonder I don't seem to care about speaker quality. It all makes sense now. I now get why I can go over to my parents who still have my dad's original KEF 100c, Koda 8's and B&O RL45's rears and it still sounds spectacular on Dolby Atmos demo clips or any music.

But in the age of the smart speaker it also shows why they really have to be solid. I have a Homepod and when that thing plays it sounds spectacular compared to all the others. I get why now - it's mono and dives way deeper than the others.

 

[tuga]

Could it be because their "Multichannel Listening Lab" was designed to be flexible enough to test stereo speakers too?
https://www.harman.com/documents/HarmanWhitePaperMLLListeningLab_0.pdf

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I wonder in the 20+ years since Harman has this lab, have they done a comparison between mono and stereo test? It seems perfect for it. Hmmm....

I've noticed that the speakers are not toe'ed in.
This will favour speakers with smooth directivity (penalise speakers without it), in spite of the room being very wide and the early reflection zones treated. It also favours speakers which are "bright" on-axis and penalise narrow directivity speakers such as ESLs.

That in my view is very misleading, dare I say biased (unless the studies are aiming to portray the general public and not the sophisticated audiophile).