"Cogging" Discussion

[DuncanS]

Many people don't like sound coming from behind their heads, a complaint often made by stereo supporters. I like the effect either way but in a normal listening room it's much easier to accommodate speakers with the couch against the back wall and speakers off to the sides! I don't always sit in the sweet spot either and still enjoy my surround regardless of seating position!

I'm the same speakers just behind and to the side or I'd have a smaller room! I also rely on my amps calibration delay settings to compensate for the change in positions of the speakers, not perfect but practical.

 

[AYanguas]

- Sitting between the back speakers of a 5.1 system reduces the cogging.

That is one point that I have continuously been trying to emphasize.

It also reduces content behind the listener.

Many people don't like sound coming from behind their heads, a complaint often made by stereo supporters. I like the effect either way but in a normal listening room it's much easier to accommodate speakers with the couch against the back wall and speakers off to the sides! I don't always sit in the sweet spot either and still enjoy my surround regardless of seating position!

I do really like the sounds coming from behind. When Atmos mixes use objects that come from the Surround Backs (7.1) my immersion effect improves, almost as much as when sound comes from above.

I have my Surround Speakers at the sides (90 to 95º), Sometimes get binaural cues that put the sound "inside my head".

That binaural cues make me perceive that the sound is coming from above (What? dont playing Atmos!). I stand up and the effect dissapears.

Sometimes the sound overrides the fronts. Not suitable for Quad listening. I have to lower levels, in addition to proper AVR calibration.

Sometimes is better to have Surrounds located at the Back, reconfiguring 5.1 to the Surround Backs of 7.1. But.... time consuming.

 

[LB-V]

I have my Surround Speakers at the sides (90 to 95º), Sometimes get binaural cues that put the sound "inside my head".

I was playing with my rear speakers last night, and they ended up closer and more to the sides. And bam...I swear I had music inside my head. I thought I had finally gone mad reading QQ and thinking about content in all of these fine threads. I told myself it must just be the late hour and my craziness. But now I'm going to try it again tonight...it was actually a little odd. But I liked it.

Probably didn't hurt that I was listening to Dan Fogelberg Captured Angel and Lighthouse One Fine Morning - both new to me thanks to QQ, and extremely nice through the SM.

 

[fredblue]

I was playing with my rear speakers last night, and they ended up closer and more to the sides. And bam...I swear I had music inside my head. I thought I had finally gone mad reading QQ and thinking about content in all of these fine threads. I told myself it must just be the late hour and my craziness. But now I'm going to try it again tonight...it was actually a little odd. But I liked it.

Probably didn't hurt that I was listening to Dan Fogelberg Captured Angel and Lighthouse One Fine Morning - both new to me thanks to QQ, and extremely nice through the SM.

when you position your Rear speakers directly on-axis to your ears (i.e. not toed-in and on the same plane as your main listening position, so the Rear speakers are effectively firing straight at your head rather than slightly behind you and toed-in as per the ITU recommendation) and your Receiver's individual channel distance, volume and EQ settings are spot on, you end up getting the Stereo image from the Rear pair directly inside your head, it can be a tad unnerving at times but it can also be brilliant!

 

[fredblue]

also, re this cogging business, for any of you who have Philips' 2002 demonstration SACD entitled "Surround Sound Reference Disc", check out tracks 74-78, which feature a comprehensive set of 5.1 Phantom imaging tests, culminating on track 79 in a twice round the room panorama.

if your system is setup properly, this round the room pan (incorporating Phantom Left Centre, Phantom Right Centre, Phantom Left Front to Left Rear, Phantom Right Front to Right Rear and Phantom Left Rear to Right Rear) should be smooth and i am happy to report in my little room it is buttery smooth, with no cogs, fogs, dogs or logs and no jumps, bumps, lumps or humps neither

https://www.discogs.com/release/11904929-Various-Super-Audio-CD-Surround-Sound-Reference-Disc

 

[MidiMagic]

If you don't heart the cogging good for you. You have somehow trained your ears to hear it correctly. I have not had that kind of luck.

My surround speakers are 40 degrees behind the listening position. It works fine with Dolby Surround with no cogging.

Since I am interested in concert-hall ambience, I want the surrounds behind me.

 

[AYanguas]

.......
... you end up getting the Stereo image from the Rear pair directly inside your head, it can be a tad unnerving at times but it can also be brilliant!

Yes, I find it really brilliant, unless it hides the front sound. I feel like wearing some inexistant headphones, and enjoing the wide sound stage.

This reminds me some comments about the Bruce Soord Atmos mixing on the Pineapple Thief studio Concert "Nothing But The Truth", when you hear the Bruce voice inside your head, but only in a very narrow sweet spot, just in the middle of the side surrounds.

 

[ar surround]

[/QUOTE]
Mine is all of the above and fart-

also, re this cogging business, for any of you who have Philips' 2002 demonstration SACD entitled "Surround Sound Reference Disc", check out tracks 74-78, which feature a comprehensive set of 5.1 Phantom imaging tests, culminating on track 79 in a twice round the room panorama.

if your system is setup properly, this round the room pan (incorporating Phantom Left Centre, Phantom Right Centre, Phantom Left Front to Left Rear, Phantom Right Front to Right Rear and Phantom Left Rear to Right Rear) should be smooth and i am happy to report in my little room it is buttery smooth, with no cogs, fogs, dogs or logs and no jumps, bumps, lumps or humps neither

https://www.discogs.com/release/11904929-Various-Super-Audio-CD-Surround-Sound-Reference-Disc

I wonder if there is something like this test pan roaming around on the internet as open source. The problem is that if things aren't arranged properly, room layout may preclude rearrangement of one's speaker layout without suffering spousal banishment from one's house.

...in my little room it is buttery smooth, with no cogs, fogs, dogs or logs and no jumps, bumps, lumps or humps neither...

But is your room fart-free? When my bloody basement dehumidifier pops on it sounds like a giant fart emitting from between the right surround and right rear speakers. This effect occurs even though the dehumidifier is in another room. Drives me bananas...and not the good @Snood kind.

 

[Soundfield]

My surround speakers are 40 degrees behind the listening position. It works fine with Dolby Surround with no cogging.
Since I am interested in concert-hall ambience, I want the surrounds behind me.

I thought that at one time, but I realised that since I don’t sit in the middle of the stalls there was unlikely to be all that much reverberation coming from behind me in most concert venues (there are some obvious exceptions). I like to ‘calibrate’ my ears when attending concerts or the opera and take a few moments to listen the sound of the space with my eyes closed. In the opera house I will always sit in an elevated seat at the rear of the house. In the London Coliseum for example this would usually be in the Dress Circle-

and in Covent Garden it would usually be in the Donald Gordon Grand Tier-

Typical of such venues, the tiered seats in both are fairly close to the rear wall and each seating level is quite confined (particularly vertically) and acoustically fairly dead (especially when filled with bodies). So in practice the reverberant space is perceived as being largely in front of you. As a result I now place my chair pretty much between my ‘rear’ speakers (but they are toed in so not on axis with my ears). On good recordings, with playback levels set correctly, I find this agrees well with my calibration listening. Actually it sometimes sounds even better with the rears slightly ahead of the chair but isn’t really practical in my room on a day-to-day basis and doesn’t work particularly well with less ambient recordings.

 

[ssully]

This is an aside comment: For any of you who have Dolby Surround capability, try playing the stereo version of the track One Fine Morning. It's really great with Dolby Surround. Sounds as if the song was mixed for the codec decades before it existed.

There's a whole QQ thread devoted to stereo tracks that sound good in Dolby/DTS upmixed surround, is there not?

 

[ssully]

I wonder if there is something like this test pan roaming around on the internet as open source. The problem is that if things aren't arranged properly, room layout may preclude rearrangement of one's speaker layout without suffering spousal banishment from one's house.

An SACD demo/test disc called Stay in Tune with PentaTone from 2005 offers a full array of phantom image tests for a 5.1 setup. IME excellent phantom imaging between front L/surround L and between front R/surround R is much rarer to achieve than good front-only or surround-only phantoms.
The disc also has a Panorama (circling) track.

30 - Phantom left center
31 - Phantom right center
32 - Phantom left front left rear
33 - Phantom right front right rear
34 - Phantom left rear right rear
35 - Panorama (twice)

I converted these DSD tracks (and all the others!) to PCM to make them more generally useful. DSD is stupid.

My surround speakers are at a shallow angle -- ~110 degrees -- beyond my main LP , and toed-in. They are identical to my other speakers and all are calibrated and 'room-eq'd' by my AVR.

 

[fredblue]

An SACD demo/test disc called Stay in Tune with PentaTone from 2005 offers a full array of phantom image tests for a 5.1 setup. IME excellent phantom imaging between front L/surround L and between front R/surround R is much rarer to achieve than good front-only or surround-only phantoms.
The disc also has a Panorama (circling) track.

30 - Phantom left center
31 - Phantom right center
32 - Phantom left front left rear
33 - Phantom right front right rear
34 - Phantom left rear right rear
35 - Panorama (twice)

I converted these DSD tracks (and all the others!) to PCM to make them more generally useful. DSD is stupid.

My surround speakers are at a shallow angle -- ~110 degrees -- beyond my main LP , and toed-in. They are identical to my other speakers and all are calibrated and 'room-eq'd' by my AVR.

oh yeah, i forgot about that one from Pentatone, its got the same test tracks as that Philips Reference SACD i mentioned previously, it used to be fairly cheap and common but like a lot of that stuff seems quite scarce now, 1 copy on Discogs at the mo.

https://www.discogs.com/release/9619391-Various-Stay-In-Tune-With-Pentatone

 

[stevendive]

[ANY surround system has cogging unless something is done to eliminate it.]


[/QUOTE]

Ambisonics does not exhibit cogging, not even 2 channel UHJ.

 

[MidiMagic]

[ANY surround system has cogging unless something is done to eliminate it.]

Ambisonics does not exhibit cogging, not even 2 channel UHJ.
[/QUOTE]
The phasing in Ambisonics might be the 'something done to eliminate it'.

I have never had the opportunity to hear an Ambisonic decoder playing an Ambisonic recording.

 

[stevendive]

Ambisonics does not exhibit cogging, not even 2 channel UHJ.

The phasing in Ambisonics might be the 'something done to eliminate it'.

I have never had the opportunity to hear an Ambisonic decoder playing an Ambisonic recording.
[/QUOTE]

Not exactly. Ambisonics is a soundfield reconstruction technique, so phasing as an issue is somewhat moot. It is often overlooked that ambisonic recordings conserve both the velocity and energy components of the sound in space for 2D and 3D and the processor uses these 3 or 4 signals, respectively (horizontal and spherical), to reconstruct the soundfield around the listener. Velocity (phase) and energy with direction relationships are conserved throughout for all directions.

What is more, velocity and energy cues are never in conflict in relation to direction and frequency, which is where the shelf filters come in and divide the processor into velocity and energy optimisation sections.

Ambi processors also include near field compensation for smaller loudspeaker arrays. NFC is used in order to deal with bass boost due to coupling effects at small driver spacing.

Looking at 2-channel UHJ, compromises have to be made for the 2 channel fold-down, which gives a somewhat phasey, not quite in focus rear sound stage.

 

[MidiMagic]

Right, as far as I know.

What about studio recordings released in Ambisonics?

I have also experienced similar effects in my Surrfield experiments. The multiple microphones provide the necessary sound cues, No cogging exists in my Surrfield recordings. A standard QS or Dolby Surround/PL/PLII decoder plays these back.

 

[stevendive]

Right, as far as I know.

What about studio recordings released in Ambisonics?

I have also experienced similar effects in my Surrfield experiments. The multiple microphones provide the necessary sound cues, No cogging exists in my Surrfield recordings. A standard QS or Dolby Surround/PL/PLII decoder plays these back.

As far as I’ve seen, the few releases in recent years are a small number of UHJ, probably made in studio using ambisonic panning law, matrixed from B-Format. But there was mention earlier of one or two recent full 2D B-Format releases on Bandcamp (in UHJ, Kymatic - Dar-As-Sulh and SOUNDkitchen - Ilha Verde, and in B-Format 1st and 3rd Order, Lasso Skinny - Machine). Bandcamp tagging leaves something to be desired and a careful read is needed of album info’.

I can’t process beyond 1st order B-Format, sadly, and at least 8 speakers would be required.

 

[ar surround]

One thing I've noticed since making my own mixes is that I can make a sound move from the LR speaker to the Front Phantom Center to the RR speaker. Yet psycho-acoustically, I hear it as panning from LR to LF to Front Center to RF to RR.

 

[ar surround]

@MidiMagic , I like term “cogging“ that you coined to describe this phenomenon.

“My definition is that a sound on one side of the listener that is supposed to be smoothly panning forward or back instead sounds like it is suddenly jerking from one speaker to another.

For example, if the sound comes from the back around to the left and then to the front, it sounds like it stops at the left back, then it stops at the left side, and then it stops at left main.

This is true even if the sound is actually being panned smoothly. You have to turn your head to the left to hear the smooth pan. Human hearing does not hear smooth pans between speakers when all of them are to the same side of the head.”

Phantom side images do not seem to work either. I suspect that my way of mixing a LB to Front Center to RB pan (see post above) works better because there is never more than one side speaker in play.

 

[par4ken]

If your speaker are placed close enough together there is no or minimal "cogging". If a sound is being panned around the room it is only natural that you would move your head to follow it. With the rear speakers far removed from the front you get the hole in the middle just as you do when the front speakers are too far apart.

Panning is used mainly as a gimmick, while I love the effect it is not a integral part of a typical surround recording, so why worry about it?

I would not want any artificial delay added to my music system!