In Appreciation of Mono Listening

[spacevector]

For the past week, I have been comparing some speakers in my living room. Set up is quite simple - I have two Chromecast Audio (CCA) devices each feeding a separate integrated amplifier. The CCA's are grouped and each play the same music from Spotify. I mute-unmute the amplifiers to switch between the speakers.

I have tried this switching comparison in both stereo and mono (by leaving one speaker disconnected).

I must say that it seems much easier to gauge the tonal balance of the speakers in mono. It feels like mono listening frees up brainspace (mine is quite limited) by not having to focus on center image, soundstage, etc. Instead I can focus entirely on the quality of the sound from a single speaker.

While listening in mono, I was surprised to find that even a single speaker can create a sense of space. With just a single speaker playing, I can clearly tell that there is magic in the recording with sounds coming from a sphere (or cylinder) around the speaker instead of just the speaker driver themselves. In some cases, it even seemed like the sound was coming from elsewhere in the room! I am quite baffled by this - it is likely due to room interaction but I would really like to learn more about how a single speaker can create spacious sound like what I am hearing.

Variation of tonal balance as you move around also becomes easy to gauge since you can focus on a singular source of sound.

When I read the speaker reviews here initially, I scoffed when I learnt that Amir is performing his listening tests in mono. Now I feel like that is the only way this test should be performed. I used to think that in mono, half the music is missing - it ought to sound odd but not really - for most of the tracks that I used, it really sounds like its all there. Some instruments or effects which are only mixed in one channel may make your music sound odd but for me, I hardly noticed the missing music.

Mono listening has truly been an eye opener for me - so much so that I'm contemplating a set up which downmixes 5.1 and stereo content to mono and has a single high quality speaker doing the work. Any ideas on how this might be done effectively? I understand that stereo recordings exploit phase to create the magic of stereo and seems like just averaging (summing) the channels may not be the ideal way.

I encourage all audiophiles to give mono listening a try - specially when comparing speakers or attempting to set speaker toe-in. Instead of messing with both speakers, just listen in mono and find the sweet spot for tonal balance.

 

[Senior NEET Engineer]

I think if the mono speaker is to the side, then you're not going to be able to asses the quality of the side wall reflections.

 

[spacevector]

I think if the mono speaker is to the side, then you're not going to be able to asses the quality of the side wall reflections.

If the quality of the overall sound as heard does not diminsh when moving about then the quality of sidewall reflections must be good?

If not, then the same limitation applies to stereo listening as well?

 

[amirm]

I think if the mono speaker is to the side, then you're not going to be able to asses the quality of the side wall reflections.

Why not? You still get an image shift towards the one wall.

 

[HooStat]

Interesting idea. Just to clarify, are you listening to one channel (e.g., left or right)? Or are you using something that sums the channels and creates a mono signal? It probably doesn't matter much, but I am just curious.

 

[aarons915]

I'm with you on this. I did a comparison a year or so back and had 2 speakers at a stalemate in stereo but switched to Mono and blind and it became easy to pick a winner and was unanimous on every song. Mono also makes the comparison much easier as you can set up a pair of speakers in stereo using a mono signal and switch instantly back and forth.

 

[richard12511]

I'm with you on this. I did a comparison a year or so back and had 2 speakers at a stalemate in stereo but switched to Mono and blind and it became easy to pick a winner and was unanimous on every song. Mono also makes the comparison much easier as you can set up a pair of speakers in stereo using a mono signal and switch instantly back and forth.

How can you be sure that it's not simply a case of one speaker being better for mono, but they're equal in stereo? In such a case, one speaker would always win the mono comparison, but they would always tie the stereo comparison.

 

[aarons915]

How can you be sure that it's not simply a case of one speaker being better for mono, but they're equal in stereo? In such a case, one speaker would always win the mono comparison, but they would always tie the stereo comparison.

Well for one, since I was sighted originally, it's possible doing the comparison blind also helped, I can't be sure how much of the difference was due to mono and due to being blind vs sighted. If you're aware of Dr. Toole's experiment showing the preference ratings of the same speakers in mono and stereo, the differences were much greater in mono which is partly why they test in mono. Their theory is that we're much more discerning in mono because directivity differences are more pronounced and there is less confusion due to stereo crosstalk, etc.

Another point I've made on this topic is that if 2 speakers are identical, what would possibly make them sound different in mono vs stereo? If people believe that you need to listen in stereo to truly compare speakers, it seems like they are claiming that there is some kind of interaction between 2 speakers in stereo that doesn't exist in mono. If you break each stereo channel down, each speaker is still receiving a signal that it needs to playback accurately, no different than mono.

 

[spacevector]

Interesting idea. Just to clarify, are you listening to one channel (e.g., left or right)? Or are you using something that sums the channels and creates a mono signal? It probably doesn't matter much, but I am just curious.

Just using one channel right now although I am now interested in a to-mono downmixer.

 

[restorer-john]

I encourage all audiophiles to give mono listening a try

It's the latest thing...go minimalist, like fixed speed bikes and foraging for edible plants. Reduces your energy footprint by 50% and saves half your money too. Put the savings toward a nice monoblock amp and call it done I say.

And you know when you see a single speaker 2nd hand really, really cheap because the other one is missing- guess what? It's perfect for your mono setup!

I'm all over it too- thanks Amir.

 

[richard12511]

Well for one, since I was sighted originally, it's possible doing the comparison blind also helped, I can't be sure how much of the difference was due to mono and due to being blind vs sighted. If you're aware of Dr. Toole's experiment showing the preference ratings of the same speakers in mono and stereo, the differences were much greater in mono which is partly why they test in mono. Their theory is that we're much more discerning in mono because directivity differences are more pronounced and there is less confusion due to stereo crosstalk, etc.

I'm aware of Dr. Toole's study, and I agree that it's much easier to assess tonality in mono. I also think it's much easier to setup a mono test. You don't have to spend hours messing with speaker placement and toe in. Just plob it right in front and get started.

I think if you're having trouble picking a winner in stereo, you absolutely need to do a mono test, as they can be (ime) quite enlightening, and can(and most probably will) help you pick the better sounding the speaker. However, in a scenario where the stereo test of A vs. B is a tie, and speaker A wins the mono test, by choosing speaker A, your assuming that the stereo test result is a false negative(ie speaker A would be preferred there too, if enough tests were done). But, what if that's not the case? What if that assumption is false? What if A vs. B in stereo really is a true tie? Speaker B could be introducing positive stereo interactions that perfectly offset the tonality advantages of A. If this is the case, and there exist other factors(price, aesthetics) that favor B, then it's possible that the mono test has actually duped us into picking the wrong speaker. Honestly, I think this scenario is unlikely. More often than not, I believe the assumption will prove to be true. However, I do have some doubts when it comes to two well engineered speakers with wildly different dispersion characteristics. I probably wouldn't put much faith in a mono test with an Ohm Walsh vs Danley SH50, for example.

Another point I've made on this topic is that if 2 speakers are identical, what would possibly make them sound different in mono vs stereo? If people believe that you need to listen in stereo to truly compare speakers, it seems like they are claiming that there is some kind of interaction between 2 speakers in stereo that doesn't exist in mono. If you break each stereo channel down, each speaker is still receiving a signal that it needs to playback accurately, no different than mono.

IME, dispersion width is the answer to your first question. Owning both narrow and (many)wide dispersion designs, and having compared them many times in both mono and stereo, narrow dispersion and wide dispersion speakers absolutely interact with one another differently in a stereo pair, and those differences are not present in mono. Personally, I think this is where the preference for narrow dispersion(however small that minority may be) comes from. My guess is that super wide dispersion(or omni) speakers should be almost universally preferred in mono, all other things held constant.

 

[Blumlein 88]

If you can find true stereo recordings using a pair of spaced omnis, you already have dual mono.

 

[BillH]

For the past week, I have been comparing some speakers in my living room. Set up is quite simple - I have two Chromecast Audio (CCA) devices each feeding a separate integrated amplifier. The CCA's are grouped and each play the same music from Spotify. I mute-unmute the amplifiers to switch between the speakers.

I have tried this switching comparison in both stereo and mono (by leaving one speaker disconnected).

I must say that it seems much easier to gauge the tonal balance of the speakers in mono. It feels like mono listening frees up brainspace (mine is quite limited) by not having to focus on center image, soundstage, etc. Instead I can focus entirely on the quality of the sound from a single speaker.

While listening in mono, I was surprised to find that even a single speaker can create a sense of space. With just a single speaker playing, I can clearly tell that there is magic in the recording with sounds coming from a sphere (or cylinder) around the speaker instead of just the speaker driver themselves. In some cases, it even seemed like the sound was coming from elsewhere in the room! I am quite baffled by this - it is likely due to room interaction but I would really like to learn more about how a single speaker can create spacious sound like what I am hearing.

Variation of tonal balance as you move around also becomes easy to gauge since you can focus on a singular source of sound.

When I read the speaker reviews here initially, I scoffed when I learnt that Amir is performing his listening tests in mono. Now I feel like that is the only way this test should be performed. I used to think that in mono, half the music is missing - it ought to sound odd but not really - for most of the tracks that I used, it really sounds like its all there. Some instruments or effects which are only mixed in one channel may make your music sound odd but for me, I hardly noticed the missing music.

Mono listening has truly been an eye opener for me - so much so that I'm contemplating a set up which downmixes 5.1 and stereo content to mono and has a single high quality speaker doing the work. Any ideas on how this might be done effectively? I understand that stereo recordings exploit phase to create the magic of stereo and seems like just averaging (summing) the channels may not be the ideal way.

I encourage all audiophiles to give mono listening a try - specially when comparing speakers or attempting to set speaker toe-in. Instead of messing with both speakers, just listen in mono and find the sweet spot for tonal balance.

I dont know about downmixing 5.1 but for stereo I have to assume that my Denon Integrated amps' mono setting is a simple sum of L and R.

 

[Senior NEET Engineer]

Why not? You still get an image shift towards the one wall.

Quality of early sidewall reflections mainly contribute to perception of soundstage (imaging, spaciousness).

I'm used to music being anchored at the center in front of me and like it that way. The loss in sound quality from image shift would dominate my assessment of the soundstage and make me less discerning of differences between speakers. The extent of the distraction is such that I'd rather listen to mono LS50 (4.5 rating) centered than mono Genelec 8341A w/ sub (8.4 rating) to the side.

 

[daftcombo]

When evaluation a speaker in mono, do you convert both stereo channels to mono?
If so, how to avoid phase cancellation?

 

[BenB]

I designed and built a pair of multi-way line array speakers (picture attached). When oriented upright, the dispersion is wide horizontally and narrow vertically. When placed on their sides, the dispersion is narrow horizontally and wide vertically. This allows for a well controlled test for preferences in dispersion characteristics. The reason this is relevant to this thread is this:

The perceived difference between the vertical and horizontal orientation of the speaker is actually larger in stereo than it is in mono (well, according to the two people who have performed this particular test). In stereo, the soundstage is much wider with the vertical orientation (wide horizontal dispersion), and preference was obvious. In mono, any difference was very subtle, and preference was difficult (or impossible) to establish.

 

[spacevector]

When evaluation a speaker in mono, do you convert both stereo channels to mono?
If so, how to avoid phase cancellation?

I recently started doing that when comparing two speakers in mono. On some music, the difference between the channels was too much (for example, one channel with keyboard, other with guitar). For now, I have only found a simple method in Effects panel of Peace. I do not know what it does with phase but it at least lets me send same music to both LR speakers.

 

[spacevector]

The perceived difference between the vertical and horizontal orientation of the speaker is actually larger in stereo than it is in mono (well, according to the two people who have performed this particular test). In stereo, the soundstage is much wider with the vertical orientation (wide horizontal dispersion), and preference was obvious. In mono, any difference was very subtle, and preference was difficult (or impossible) to establish.

Would this become more apparent if listener moves around when evaluating in mono?

 

[tuga]

Well for one, since I was sighted originally, it's possible doing the comparison blind also helped, I can't be sure how much of the difference was due to mono and due to being blind vs sighted. If you're aware of Dr. Toole's experiment showing the preference ratings of the same speakers in mono and stereo, the differences were much greater in mono which is partly why they test in mono. Their theory is that we're much more discerning in mono because directivity differences are more pronounced and there is less confusion due to stereo crosstalk, etc.

The differences in "spatial quality" were much greater in mono. This was due to differences in directivity. The Quad, but also the Kef have an overall smoother on- and off-axis response (i.o.w. better balance) than the Rega and yet the latter was preferred. I am convinced that this was due to the wider-directivity of the Rega, which seems to be preferred by most people and I would expect by most if not all Harman-trained listeners.
I disagree with Toole's interpretation of the data.

 

[richard12511]

I designed and built a pair of multi-way line array speakers (picture attached). When oriented upright, the dispersion is wide horizontally and narrow vertically. When placed on their sides, the dispersion is narrow horizontally and wide vertically. This allows for a well controlled test for preferences in dispersion characteristics. The reason this is relevant to this thread is this:

The perceived difference between the vertical and horizontal orientation of the speaker is actually larger in stereo than it is in mono (well, according to the two people who have performed this particular test). In stereo, the soundstage is much wider with the vertical orientation (wide horizontal dispersion), and preference was obvious. In mono, any difference was very subtle, and preference was difficult (or impossible) to establish.

View attachment 119775

This makes sense. Tonality differences are highlighted in mono, but you can still judge in stereo. Soundstage/imaging differences are highlighted in stereo, but you can still judge them in mono. At least this makes sense to me