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Do loudspeakers need to image precisely?

RayDunzl

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Ray, I don't think that ML panels are really good example of narrow disp speakers. The backside radiation adds to ambient sound a helluva lot!

That may be true, but my feeble measures here indicate the reflection from the wall behind the speaker is at a level of 0.041 (relative to a level of 1 for direct sound), or -27.74dB. That is also the loudest of the early reflections by 6dB or so

For the JBL, the biggest reflection is 0.181 relative to the direct sound, at -14.84dB, or 12.9dB higher, more than twice as loud (10dB).

Looking at the impulse response, the JBL provides six reflections above the level of the highest reflection (the backwave) of the ML.
 

garbulky

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I read that article. If your speaker system is lacking proper imaging, then it is lacking in other departments. If you want good sound reproduction, you have to get the imaging to work too. How can one NOT care about the imaging for music? If you are listening to music in real life, it's all about great imaging. And yes this great imaging can sound diffuse and not pinpoint like we are used to in certain purposefully engineered recordings, but the level of realistic sound reproduction cannot be engineered without great imaging.

As a hobby I make several newbie level recordings in stereo of unamplified acoustic instruments and people singing and the stereo imaging I get from my very amateur efforts is pretty stunning. There's tons of imaging detail. To emphasize these are recordings of real space not some close miked pre-panned processed stuff. In fact there's no processing other than me setting the analog gain knob so it doesn't clip the recording. Having said that, some of the biggest challenges to great imaging is room acoustics. I've seen plenty of live rooms without proper treatment where people have uber expensive gear for "accuracy" and completely ignore the room with some theoretical bs for justification (don't want to dull the room etc).
 

DDF

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A recent editorial:
https://www.stereophile.com/content/clowns-left-me-jokers-right
A case is made that in except for a few seats image locations are not precise in a symphony. Rather, it is a shapeless monophonic mass.

I attend ~ 20 chamber to full orchestra classical acoustic performances over the course of each season, spanning ~ 5 venues from churches with wonderful acoustics to universities with terrible acoustics, to our large purpose built symphony hall. My favorite symphonic locations are orchestral floor, rows 9 -15, off center. I always listen through periods with eyes closed purposely paying attention to the sense of space and localization.

While individual string instruments in sections are impossible to localize, the soloist, individual winds, individual horns or percussion are a breeze to localize with eyes closed. The gap from reality presented by stereo IME isn't so much the over specificity of localization, but it's the lack of any real envelopment or sense of acoustic scale. I think this lack of realistic scale in stereo heightens the perception of hyper localization. Even garden variety HT receiver upmixed 5.1 does a much better job of presenting a real sense of space than stereo, IME
 
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Ron Texas

Ron Texas

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I attend ~ 20 chamber to full orchestra classical acoustic performances over the course of each season, spanning ~ 5 venues from churches with wonderful acoustics to universities with terrible acoustics, to our large purpose built symphony hall.

Churches have wonderful acoustics, interesting.
 

watchnerd

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Whilst it's true that many if not most even classical recordings are multi-miked, there are still some labels, like Nimbus, that record in a purist fashion. They record in long takes, generally each movement in one take, using the edit, as they put it, "to save a performance, not to create one".

Decca also used to record classical music using the Decca Tree microphone arrangement, which I've used successfully myself for larger ensembles.

Binaural dummy-head recordings are something of a special case, and personally I don;t rate them particularly highly. I like Blumlein crossed figure-of-eight or coincident cardioids for stereo recordings, or indeed Decca Tree. Having said that, for live broadcast of small bands, it tends to be close-miked and pan-potted as drums obliterate everything.

S.

Nimbus, Decca, and other minimalist settings are less complicated, but:

1. The mics still aren't located where your ears would be in an audience -- they're typically elevated, not at ear height.

2. Wherever the mics are, it's particular for that location -- which may or may not be where you're sitting on concert night.

3. Mics are transducers. They all color the sound.

4. Mixing happens. Mixing effects imaging.

5. When I'm mixing, I can move a soundstage forward or backwards just by using PEQs.

6. Your listening room isn't the concert hall.

7. Auditory memory is bad.


Audio reviewers are woefully naive about the sausage making involved in recordings.

And Harry Pearson is to blame for this nonsensical idea that a vague remembrance of a concert hall is an Absolute Sound to be used as a reference.

Unless I'm recording a musical instrument in my listening room, at my listening position, the circle of confusion is just too large.
 
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watchnerd

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If you are listening to music in real life, it's all about great imaging.

I don't experience great imaging when I listen to an electronically amplified blues band in a small crowded bar without any mixing board and each instrument having it's own amp.

I don't experience great imaging when I'm walking through a train station and hear a busker playing the saxophone down the corridor.

Last night, while eating dinner al fresco in Waikiki, there was a folk guitarist about 70 meters away, across a pond, with palm trees in between, using a cheap portable PA, the sound reverberating around a courtyard. There wasn't anything I would call imaging.

On Sunday there was a street parade, with a marching band, and the wall of sound coming from them had no resemblance to what I think of as imaging.

When I hear a live violin playing through an open window, it's not a sense of imaging that lets me know it's live.

For me, it's transients and dynamics.
 

Cosmik

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How many people here know that Blumlein stereo imaging is 'true' in the sense that it reproduces the angles subtended by the actual acoustic sources at the microphone? (with restrictions, such as the maximum extent due to the angle of the speakers which - I think I am right in saying - should technically be at +/-45 degrees to the listener). And that this is a fairly robust mechanism that doesn't fall apart with minor shifts in position of the listener or turning of the head.

Time-of-arrival at the ears only tells you that an acoustic source lies somewhere along a straight line radiating out from the listener, so by creating a 'fake' time-of-arrival difference at the listener's ears using level differences between the speakers (no delay difference, and the acoustic crossfeed between channels is part of the mechanism not a defect), the Blumlein mic pair & stereo speaker configuration does much more than just give you some left, right and a blob in the middle. The brilliant, fine separation and stable placement of the sources that you hear with good imaging isn't just your imagination: it's 'real' (or can be). And the humble panpot is the 'correct' way to create artificial stereo placements that, too, are stable for the listener when listening over speakers.

It is one of those things in audio that works much better than we might expect from just hearing a description of it.
 
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watchnerd

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How many people here know that Blumlein stereo imaging is 'true' in the sense that it reproduces the angles subtended by the actual acoustic sources at the microphone? (with restrictions, such as the maximum extent due to the angle of the speakers which - I think I am right in saying - should technically be at +/-45 degrees to the listener - or maybe not, I'll check). And that this is a fairly robust mechanism that doesn't fall apart with minor shifts in position of the listener or turning of the head.

Time-of-arrival at the ears only tells you that an acoustic source lies somewhere along a straight line radiating out from the listener, so by creating a 'fake' time-of-arrival difference at the listener's ears using level differences between the speakers (no delay difference, and the acoustic crossfeed between channels is part of the mechanism not a defect), the Blumlein mic pair & stereo speaker configuration does much more than just give you some left, right and a blob in the middle. The brilliant, fine separation and stable placement of the sources that you hear with good imaging isn't just your imagination: it's 'real' (or can be). And the humble panpot is the 'correct' way to create artificial stereo placements that, too, are stable for the listener when listening over speakers.

It is one of those things in audio that works much better than we might expect from just hearing a description of it.

Sure, but....

How many times have you read an audio reviewer rave about the amazing imaging of some piece of gear while using some studio created classic rock as the reference source?

"OMG Rush sounds like they're in my room! I can tell Neil Pert's kit is 12 feet behind and slightly to the left of Geddy Lee!"

(me rolling my eyes, pretty damn sure they, like most classic rock, were in different rooms of the studio laying down their tracks separately, if they were even all in the studio at the same time)
 

Cosmik

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Sure, but....

How many times have you read an audio reviewer rave about the amazing imaging of some piece of gear while using some studio created classic rock as the reference source?

"OMG Rush sounds like they're in my room! I can tell Neil Pert's kit is 12 feet behind and slightly to the left of Geddy Lee!"

(me rolling my eyes, pretty damn sure they, like most classic rock, were in different rooms of the studio laying down their tracks separately, if they were even all in the studio at the same time)
But there's no reason that the recording hasn't synthesised something that resembles that scenario i.e. the panpot creates the angle, and the EQ, reverb and recorded acoustics create the depth. It's something that is nice to hear even if it isn't an actual sonic hologram of a real event.
 

watchnerd

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But there's no reason that the recording hasn't synthesised something that resembles that scenario i.e. the panpot creates the angle, and the EQ, reverb and recorded acoustics create the depth. It's something that is nice to hear even if it isn't an actual sonic hologram of a real event.

LOL you act like every producer is Alan Parsons. Most don't get paid to care.

And what does any of this matter for a modern producer making popular recordings today that will be listened to on earbuds or a mono Bluetooth speaker?
 

Cosmik

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From the Stereophile article I linked to:
...one of the benefits of wide-stage stereo is "directional unmasking." When two similar sounds arrive at the listener from the same direction, they tend to be heard as a single composite sound whose character is dominated by the louder component. But if the sounds are separated by even a small angle (5 degrees or so), they are easily resolved by the ear as individual sources.
...stereo provides a basic improvement in the quality of the sound, giving you more to hear---making it easy, for instance, to resolve the individual sounds of two similar instruments playing in the same frequency range (eg, a duet between clarinet and English horn in the middle of the orchestra). It also allows you to resolve the reflections of these sounds as they bounce off the walls of the stage, giving you a sense of the width or depth of that stage.
...improved resolution of the soundstage lets you hear everything with less mental effort, you may experience less listening fatigue.
So yes, your speakers should provide good imaging. It isn't just 'an effect', but a means to hear more in the recording and reduce listening fatigue.
 

watchnerd

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From the Stereophile article I linked to:

So yes, your speakers should provide good imaging. It isn't just 'an effect', but a means to hear more in the recording and reduce listening fatigue.

I'm not saying speakers shouldn't produce good imaging.

I'm saying:

1. Using audio memories of live music experiences as a reference for what imaging should sound like is precarious

2. Lots of great or popular music performances / albums have crap imaging, so be careful about your reference standards
 

Cosmik

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LOL you act like every producer is Alan Parsons. Most don't get paid to care.
I rather think that any producer would be generating these effects in stereo whether they wanted to or not! The panpot *will* give you an angle, and the other stuff will probably give you a sense of depth whether you like it or not.
And what does any of this matter for a modern producer making popular recordings today that will be listened to on earbuds or a mono Bluetooth speaker?
Microphone techniques and other stuff should be different for headphones, which don't have the acoustic crossfeed that speakers provide. And, indeed, stereo L-R combined into mono can sound worse than a correctly-produced mono recording.
 

watchnerd

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And, sadly, so many audiophile albums with great imaging are things I don't really want to listen to...the North Newfoundland Dulcimer Enthusiasts and such.
 

Cosmik

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99.99% of music is not produced this way.
I'm sure you're right. But most recordings will sound 'OK' on speakers or headphones, because if all else fails, you still have the music and performance itself to listen to. Great imaging is a bonus, but not essential for enjoying the music at its basic level.

Great imaging takes it to the next level, and allows you, perhaps, to enjoy a wider variety of music because you begin to hear more in the recordings.
 

Stonetown

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I just must say that comparing my wide radiation angle speakers in our TV room, to my narrow highly directive vintage speakers in my HIFI-room, makes a distinct difference in the stereo image. In the TV room you hear directly where the speakers ar standing and that the audio is coming from there, but in the HIFI room there is only an audio image and you cannot tell where the speakers are standing actually (when not looking). Wide or narrow speakers makes a surprisingly big difference in the total listening experience. When you tried narrow you cannot go back :) As I said before, you have to accept that the narrow speaker/good image is only for a single listener, sitting in the listening rooms "sweet spot", because when getting outside the sweet spot the audio quality is deteriorating quickly. But when watching TV or movies in the living room this is mostly not acceptable because we are normally more people there and we all cannot fit into the sweet spot.
:)
 

b1daly

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Hi

The issue is complicated. Speakers have a very hard job to do: Reproducing as faithfully the electrical signical that is fed to them. They mange to get some to a point where we can recognize what comes out but their degree of faithfulness to the signal is abysmal... Yet we make something out of it to the point that it can be preferred to the real live sound.

:D

I think the issue is more complex than this. What we want the speakers to do is create a sonic experience that communicates the artistic intent of the recording artists. (Take this to mean the musicians, composers, arranger, engineers, producers, mastering engineers, recordings are a team effort usually.)

An electric signal only has a relationship to a sonic experience if it has been crafted to be such. Overtime mics have been developed that capture sound pretty faithfully, and if that original signal is captured, and input to an amplifier, which is connected to speakers, then some representaion of the original acoustic event does, miraculously, emanate from the speakers.

But without considerable effort, this acoustic representation will not be interesting. The "producer" of a recording is responsible for creating a signal that will communicate the musical expression with conviction.

To craft this expression, in all but the most purist recordings, the various captured signals are worked on in a studio, while listening to monitors, in the hope of creating a compelling product. This type of communication is complex, and the "accuracy " of the speakers is only one component of the process.

I record music, and one of the vexing challenges of this process is creating a recording that "translates" well to all the different playback systems that might be used to express the recording. What I usually do is rely one main set of monitors. But I will switch between various sets of speakers, as well as check mixes in other playback environments, in the hope of creating an expression which transcends the specific playback system a listener might choose. It can be shocking how different mixes sound on different systems.

There are specific qualities of a recording that help it "translate" like this, largely concerned with having a balanced dynamic spectrum, as well as overall well controlled dynamics. (I think of dynamic spectrum loosely as having a well-balanced frequency spectrum at the different dynamic levels in the signal. For example, if a recording has a ton of low-mid content on the quiet sections, and the loud sections have a lot of high-frequency content, this will be hard to represent on an average playback system.)

In any case, we all benefit because of the skill of producers/team in creating recordings that translate well across different playback systems, which means we can utilize "less than optimal" systems and still have a great listening experience.

I've been thinking about the recent discussion here about "evidence based speaker designs" a lot. The research being referenced (as evidence) points to speaker designs that in my experience I do not enjoy listening to. T

For studio monitors, I do prefer "accurate" speakers, just because it makes the project of crafting a signal that translates well more doable.

But for fun listening, I hate the sound of this type of speaker. I tend to prefer "boxy" designs, that have some cabinet resonance.

I have some provisional theories on what accounts for my subjective preference, but I'm not sure. One issue, is that speakers that are "colored" in a distinctive way can be more or less flattering to specific recordings.

I listen to mostly "rock music" (broadly defined) and I listen at low volumes. In my informed but limited experience, "accurate" speakers do not present this music very well.

It's making me inclined to do some informal blind listening, just to check what I might discover in that context.
 

FrantzM

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To me "imaging" relates to a visual stimulus, not an aural one. True, we have come to accept it as an aural artifact but it is done through manipulation. Very small settings (Jazz trio for example) and sitting at a specific location may present some aspects of what audiophiles termed as imaging but for the most part . it is with our eyes we see. our ears present a much more diffuse "image" ...
 

JanRSmit

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Yes, we do, but the point remains- the speaker puts out a 3D soundfield, i.e., it is not invariant with any translation in 3-space. This is a response to a 1D electrical signal, thus it is in essence creating new information that does not exist on the recording.

Different speakers in different rooms will create different illusions for different people.
A stereo setup produces 2 sounds, of is our hearing system that constructs a sound field. Those 2 electrical signals do contain spatial info. Just listen to a mono recorded sound and a stereo recorded sound(with 2 microphones). The mono (1mic) does not have the width dimension.
 
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