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

[goat76]

I was looking for another image and clearing out photos stuff in my phone when I came across the ff. even more crude "models" of the phantom center dip in one of A. Grimani's lecture slides:

View attachment 206588



View attachment 206589


This maybe helps illustrate partially why I mentioned I only load my phase shuffler DSP settings under certain conditions.

Is this about two-channel stereo recordings played through two loudspeakers vs the same two-channel stereo recordings played through 3 speakers with an added center channel? If so, the result of the EQ compensation will depend on how the particular recordings are mixed and which compensations are already in place.

If we assume we are talking about modern multi-microphone recordings and that the recordings in most cases are mixed using two speakers in a traditional stereo configuration, we also should assume that all the different sound objects in the mix (no matter where in the stereo field those individual sound objects may be placed) are already "sculptured" with EQ the way the mixing engineer thought they sounded good. If he/she thought something was missing in the sound of the sound object that is somewhere in the phantom center field, we should assume he would already have made an EQ compensation to those sound objects until he was satisfied with the end result. (Don't forget that the mixing engineer hears the end result of the mix through two speakers with the very same phantom problem as the end-user will.)

If we talk about recordings made with a stereo microphone technique, then an EQ compensation for the phantom center is more likely a solution to the problem. But still... if a modern mixing/mastering EQ program is used with the function of Mid/Side equalization, we still don't know if some sort of compensation is already in place.


As you can see, the stereo phantom problem can already have been addressed/handled in the mix, with or without the mixing engineer's knowledge of this particular phantom problem. In most cases as the end-users, we don't know what is done in the mix, but we should assume that if the mixing engineer hadn't been happy with how the mix sounded (and in this particular discussion, how the sound objects panned somewhere in the phantom field sounds), he would have probably done something about it.

And as you can see (#2), there can never be a "one-trick" EQ solution to the problem no matter if a center speaker is added for the playback of the two-channel stereo recording or not. It's a case-by-case solution depending on the particular recordings, it can even introduce a new problem as a "two-stacked" overcompensation if the problem is already addressed in the mix. If a center channel is added it's even possible a "negative" EQ compensation is needed as a solution to some particular recordings.

 

[Newman]

Gotta say my experience with 5.1 left a bad taste in my mouth.

Gotta say try doing it well next time.

 

[Holmz]

... Gotta say my experience with 5.1 left a bad taste in my mouth.
...

A 1/2 dozen martini’s should fix that.

 

[ernestcarl]

Is this about two-channel stereo recordings played through two loudspeakers vs the same two-channel stereo recordings played through 3 speakers with an added center channel? If so, the result of the EQ compensation will depend on how the particular recordings are mixed and which compensations are already in place.

My own very personal concern was the center channel vocals specifically in a MCH mix. The mixing and mastering was indeed done with an actual center speaker in place. To reduce the dimming or magnitude dip primarily centered at or just under the 2kHz region, a slight EQ is applied to the center channel (completely separate from the left and right) as well as some additional artificial "shuffling" of the phase -- in a very acoustically dry (treated) room -- which I do have -- this can work better. For greater bulk of 2-channel stereo music, its "effect" is very much a mixed bag... so I generally do not use it -- since I already also use other EQ compensation tricks like loudness DSP and variable shelving tone controls dependent on listening volume level and the source content etc.

 

[goat76]

My own very personal concern was the center channel vocals specifically in a MCH mix. The mixing and mastering was indeed done with an actual center speaker in place. To reduce the dimming or magnitude dip primarily centered at or just under the 2kHz region, a slight EQ is applied to the center channel (completely separate from the left and right) as well as some additional artificial "shuffling" of the phase -- in a very acoustically dry (treated) room -- which I do have -- this can work better. For greater bulk of 2-channel stereo music, its "effect" is very much a mixed bag... so I generally do not use it -- since I already also use other EQ compensation tricks like loudness DSP and variable shelving tone controls dependent on listening volume level and the source content etc.

View attachment 206637

In most cases, vocals are almost always placed dead center in a mix. If you have a center channel and the mix is indeed a multi-channel mix with an actual center channel in place, shouldn't the "stereo fault" already be solved without any need for an EQ compensation when you actually have the center channel in place? Isn't the dip around 1.9 kHz exclusively a phantom channel problem?

 

[Dogen]

I have no technical knowledge to add, but an anecdote. I was struggling for months with a secondary system in a small room with medium-quality speakers - I just could not shake the sense of the music clumping at each speaker, with a big hole in the middle. A few days ago I moved one of the speakers literally a centimeter and the hole pretty much went away. Speaker positioning was immensely important in my case.

 

[ernestcarl]

In most cases, vocals are almost always placed dead center in a mix. If you have a center channel and the mix is indeed a multi-channel mix with an actual center channel in place, shouldn't the "stereo fault" already be solved without any need for an EQ compensation when you actually have the center channel in place? Isn't the dip around 1.9 kHz exclusively a phantom channel problem?

Yes...

I do not have a center channel.

This is specifically an issue for those artificially reproducing a phantom center (by downmixing to LR) without having a real center channel speaker setup in place.

 

[goat76]

Yes...



This is specifically an issue for those artificially reproducing a phantom center (by downmixing to LR) without having a real center channel speaker setup in place.

Ah ok, I misunderstood you. I thought you had a center speaker in your system.

 

[IPunchCholla]

Gotta say try doing it well next time.

Next time I will. To get to where I am in my main listening room I have put in treatment panels based on numerous futzing sessions with speaker position, spent a ton of time on here gaining an understanding of what will make the biggest differences. Purchased equipment that will not contribute audible noise and distortion to the chain. And got a calibration microphone and software to balance, EQ, and phase adjust my speakers and spent serious time implementing it.

And my 2.0 system sounds really good (to me). The thing that made the biggest differences was room treatment/speaker placement/calibration.

If it is going to be the same amount of work and cost multiplied 4 to 9 times, it would be nice that validate it t is something that actually enhances my music listening experience.

 

[Sal1950]

If it is going to be the same amount of work and cost multiplied 4 to 9 times, it would be nice that validate it t is something that actually enhances my music listening experience.

It really doesn't have to cost near that much.
If your room will allow it, for best results just add 3 more of your current speaker for center, and 2 surrounds, amplification for them, and a surround preamp/processor. That will give you 5.1 equal in sound quality to what you have now. Then decide on compatible Atmos speakers.

 

[IPunchCholla]

It really doesn't have to cost near that much.
If your room will allow it, for best results just add 3 more of your current speaker for center, and 2 surrounds, amplification for them, and a surround preamp/processor. That will give you 5.1 equal in sound quality to what you have now. Then decide on compatible Atmos speakers.

We’re getting way off topic here, but my current speakers aren’t produced. From measurements, I’m guessing getting decent equivalents would be around $500 plus per speaker, so a couple/three grand once I toss in two more amps and a surround pre-amp. Not an issue really, if I want to do it. That is a couple months fun money. The bigger is how my space works. My house was built in 1945. The rooms are urban 1945 sized. I have two places I can do this: our bedroom and my office. The living room is a no go (spatially the living room and dining room function as a room sized hall connecting all the parts of the house together. Combined with the fireplace, picture window, patio doors, doors to the kitchen, guest room and hallway, and built-in book shelves there isn’t even space for putting a TV much less a surround system). My wife’s office is a no go. And the guest room is a no go (although it would be goodish if we were okay with our visiting friends not having a bed).

They weren’t thinking of modern electronics when they built the place, much less surround. It was built for people to gather, eat, and talk. And to sleep. It does that well at a price a working person (probably connected to the military) could afford in 1945. Now it is an upper middle class neighborhood.

So below are the two spaces I listen in. The top is my office which I have treated and calibrated my speakers to. The circles are where my LPs are. It sounds great in those circles. And good in most of the room. The bottom is our bedroom the sound bar is under the TV (the angled thin rectangle. The sub is at the foot of the bed. It sounds fine (nowhere near as good as in my office) at the LP (circle) in the bed. Stereo and 3.1 are doable to really excellent (with quite a bit of effort). Surround wasn’t easy and was more distraction than benefit. Little of what I listen to seems to be mixed for it.

I am not against the technologies. I am a bit of a geek and use tech tools to improve my life at the drop of a hat. But stereo (setup right) can work very, very well and I have yet to experience music in surround in such a compelling manner as to require me to go to the expense and effort to get my spaces to work for surround or atmos. And I enjoy my TV just fine in 3.1. Little of what I watch is enhanced by highly spatialized audio.

 

[srrxr71]

They also had textbook step response.

Is this the one they featured in that old show “beyond 2000”?

 

[MattHooper]

For speakers to truly disappear, there's one all important ingredient.

MAGIC DUST

Ask and ye shall receive!

UEF-Acoustic-Dots

www.synergisticresearch.com

(as they explain: stick 'em on the side of your speakers and experience your system disappearing! Their magic is proprietary though; the wizards making these are under strict NDAs!)

 

[Sal1950]

(as they explain: stick 'em on the side of your speakers and experience your system disappearing! Their magic is proprietary though; the wizards making these are under strict NDAs!)

I'm not sure how effective those options are?
But I can report with personal experience from back in my youth, that some things along the lines of magic mushrooms, LSD, even some really great pot, and other hallucinogenic drugs; can turn a cheap boom box and a pair of $15 headphones into an absolute SOTA HiFi. At least for a limited period of time. LOL

 

[MattHooper]

I'm not sure how effective those options are?
But I can report with personal experience from back in my youth, that some things along the lines of magic mushrooms, LSD, even some really great pot, and other hallucinogenic drugs; can turn a cheap boom box and a pair of $15 headphones into an absolute SOTA HiFi. At least for a limited period of time. LOL

Perfect solution!!!

I knew I was misspending my money somewhere in my audio journey!

 

[Thomas_A]

With respect to speakers disappearing even when sitting off-axis I made an experiment recently. I recorded pink noise with my in ear-microphones while sitting exactly in front of the left speaker in LP. I recorded left-mono-right channel signal and then listened to the result. I also made a 1000 Hz HP filter to the recorded file. I attach two files with sound in rapid succession left-mono-right that should be listened to in headphones.

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

 

[Barry_Sound]

Still wondering, would´nt you need a "dead center" mono recording to experience speakers disappearing fully? Isn´t the point of Stereo having two separate sources?

 

[Thomas_A]

Left ear "pink noise response" for left (vänster)-mono-right (höger) speaker. Correlated pink noise for the mono.

The same for right ear:

 

[Thomas_A]

Here is another one which is my voice recorded on the mac microphone and then reproduced left-both-right speaker recorded with in-ear mics, when sitting at LP but straight ahead of the left speaker. Listen with headphones.

Dropbox

www.dropbox.com

 

[Thomas_A]

I wonder what the impression of localisation from others are with the voice calling of left-both-right speakers. I know this is recorded with my own outer ears and head so impressions may vary.