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Imaging and soundstage. What are they and who hears them?

LTig

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This an exception. You can use current drive if you know the impedance curve of the speaker so you can use EQ to counteract the resulting effect on frequency response. This can be done in active speakers but not in general purpose power amplifiers where the designer doesn't know which speaker the customer wants to drive (it could work with certain magnetic planar speakers with flat impedance curve).
 
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escksu

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I have to say we have discussed this imaging thing before and I've never heard it on any system the way he describes it. The depth and height sort of thing is something I just don't hear.

Who is right? Can two people listen to the same thing and hear two totally different things?

This is very normal. So, don't be too bothered by it. Apart from ears, it has more to do with mind and how we perceive sound. Not everyone can perceive these differences. Different people perceived it in different ways. Its very very normal.

So, as long as you are enjoying what you have, thats all it matters.
 
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escksu

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I discussed this recently with a friend who makes preamps.Those preamps have a very strong reputation for creating holographic sort of imaging.That is certainly how I and many others hear it but it seems others do not notice that and concentrate more on tonal qualities and left/right spread.He installs quite subtle balance controls which help those that do seem to hear centre fill and depth type imaging to really fine tune that sort of imaging and to get it to "lock in".Again that has certainly been my experience with those sorts of balance controls.Very few systems /rooms are acoutsically symmetrical and neither is our hearing.Some buyers of those preamps have reported back to him that the balance controls do not seem work so they are clearly hearing or listening in a different way.
There is also the example of Yamaha NS 1000 speakers that continue to be much loved by many people.It is almost like they are a great tool for dividing those that hear centre/fill and depth from those that do not.Many people seem to hear that these speakers seem to be quite deficient in those traits where as others hear nothing wrong with the imaging.You can tell those that are struggling to make sense of the imaging and to say get voices to "lock in "because they tend to move their heads from side to side when listening to them.I have afriend who has alove/hate relationship with those speakers and who has owned three pairs of them only to sell them because that sort imaging or lack of it begins to really annoy him.Other people do not hear them that way.
I think it is perfectly reasonable to assume that people hear things like imaging /depth and distance perception differently.It is a bit like those picture puzzles in which an image appears almost instantly to some and never to others.It also reminds me of a bunch of us whitefellas fishing alongside some aboriginal blokes and they were catching all the fish because they could see them in the water and cast to where they were and we could not see them in the water at all.
Some people have perfect sense of rhythm or perfect pitch when they sing .those people are probably more likely to be more fussy about what they hear in a sound system too.
Of course a lot of recordings do not allow you to hear much depth.The better recording engineers like Al Schmitt however went to a lot of trouble with microphone types and positioning to try to capture it.

Yes, its mostly from the preamp. The power amp is just to take the signal from preamp and amplify it. Most power amps are designed to be as neutral as possible or "transparent". It does not impose any "colour" to the sound.

I also agree that recording itself matters alot.
 
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antennaguru

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Your room looks great and your equipment certainly is great as well. One thing I can see in the picture that can diffuse the pin-point imaging that I am accustomed to hearing is that reflective table in front of you. Just for kicks try removing it, or throwing a thick woolen blanket folded in half over it, and see if that makes a difference.

Also, have you experimented with toe-in, and maybe pulling the speakers towards you so they are more ahead of the equipment cabinet?

If any of this helps, then great. If not then please excuse my suggestions as I approach system imaging purely from a 2 speaker stereo perspective, and am not sure about the ancillary effects of the screen and other speakers in the room, nor the main speakers being back so far (mine are pulled far forward ahead of the equipment).

As to recordings I would suggest you try some simply miked recordings from Opus3 to demonstrate a natural soundstage. Cowboy Junkies first Trinity Session is also a good one for this. Sounds should not sound like they are coming from your speakers, and the speakers should instead simply vanish with the sounds coming from where musicians would be positioned over the soundstage. They should be spread left to right as well as front to rear. A fun track to test depth of image is Dire Straits Private Investigations on the Love over Gold album. About 5:42 into the track a wine glass is tossed somewhere behind the left speaker and it breaks. The depth of where it breaks and the resolution of the breakage are what you should listen for. On my reference system the wine glass hits the hard asphalt surface about twenty feet behind and a little to the left of the left speaker. As to the resolution of the breakage I hear the initial impact of the glass breaking and then the secondary breaking of the larger pieces breaking again into smaller pieces. How low you can adjust the volume and still hear this resolution tells you about the transparency of the setup. The other day I was at a friends who has a very nice system and I heard the same breakage resolution as mine but not as much depth. I think the extent of both is dependent mostly upon room setup. Again, I sincerely hope this is helpful.



Yep.
I‘ve done all that almost exactly as you have described.
The room is symmetrical 6m long and 4.5m wide. Maybe the side seating is not perfectly symmetrical but pretty close. It’s a dual purpose room as you can see.View attachment 147533
 

antennaguru

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Sorry, I forgot to mention image height as it's late and that slipped my mind. There are a couple of primary recordings I use to test this and both are Flamenco music, Pepe Romero is one and also M&K Flamenco Fever (which is also on the Ohm Imaging record). The Flamenco music is a great choice for demonstrating image height because there is singing at voice height, guitar playing slightly lower, castanets clacking overhead above everything, and finally dance shoes pounding on the floor below everything else. It's breathtaking to hear this reproduced well by speakers that simply vanish.

Almost as good an image height test are the IsoMike recordings. Especially the 2006 tests SACD where track 7 presents a college musical and dancing production where the singing comes from voices distributed across the stage, and then the tap dancing eventually starts, where the tap shoes are pounding the floor and sound lower in height than the voices. Frankly that many tap shoes suddenly starting pounding the floor will startle you if you have the volume high.

My reference system presents image height in a natural manner as I described above, but some of my other systems struggle with this.
 
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FeddyLost

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Accuphase A-70 has very low distortion
Does it have negative feedback?
There is an opinion that NF slightly blurs small details and makes imaging worse. (I.e. correction is applied after signal already released, like small echoes, so ...) And Hypex/Purifi have very deep and fast negative feedback.
Unfortunately, I don't know any good test of this opinion, and usually zero negative feedback amps have very different distortion profile.

It’s a dual purpose room as you can see
If typical "stereo condition" of your room is such (with curtains) i'm not sure that you really have something significant to collapse.
The best "imaging" room that i've heard was totally diffuse and "adjusted" for stereo-miked classics, so most modern mixed tracks was pretty flat and artificial.
My own system with a lot of absorption have decent imaging only at tracks where some attention was paid to this during mixing (i.e. Yello) or at live performance with real ambience. Or at movies mixdown, for sure.
 

JustAnandaDourEyedDude

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Who is right? Can two people listen to the same thing and hear two totally different things?
How can an amplifier (especially an amplifier that measures as well as the Purifi based amps) collapse a soundstage and imaging? Is there a scientifically plausible explanation?
Could this be part of the reason why there is a gulf between subjectivists and objectivists?
Based on what you have described so far, all four possibilities remain: (a) you and your brother are both right, (b) you are right and he is mistaken, (c) you are mistaken and he is right, and (d) both of you are mistaken.

It is possible that you and your brother have come to rely on different cues to the perception of imaging / instrument placement, and your past disagreements about it speak to that. And it is possible that the linearity of the Accuphase amp with respect to (frequency-dependent) speaker conductance versus the nonlinearity of the March Audio amp, together with the steep impedance vs. frequency dip of the Magicos, leads to different perceptions by your brother and you (due to differing ears and auditory systems and history and self-learning/training). A "scientifically plausible explanation" would be helpful only insofar as warding against dismissing possibility (a) as implausible or highly unlikely.

That you and your brother disagree on the status of imaging of your system, as also considering the many arguments about "imaging" and "soundstage" on ASR and other forums, shows that you are dealing with a "subtle" effect, as opposed to a "gross" sensory effect. With a gross sensory effect, there is much less need for caution in drawing conclusions, and indeed we could not function in day-to-day life without trusting our senses.

When it comes to subtle effects, the fuzziness of the limits of perception and the enormous complexity, inconstancy and variability of auditory perception are some the reasons why the war between subjectivists and objectivists will never end (the enormous suggestibilty of brains being another major reason). The previous responses to your OP have listed a large number of possible confounding factors, among them possible bias inherent in sighted testing. So far, both you and your brother have judged based on sighted testing which is vulnerable to psychological bias leading to biased perceptions. I can believe DBT is a PITA, and I am not suggesting a DBT by either of you (far easier to just agree to disagree), but if done it would help remove some confounding factors when it comes to subtle perceptions. As things stand, it seems to me that it would be methodologically questionable and premature to pick possibility (a) over the others, even if one could come up with a scientifically plausible scenario for it.
 
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a.dent

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Does it have negative feedback?
There is an opinion that NF slightly blurs small details and makes imaging worse. (I.e. correction is applied after signal already released, like small echoes, so ...) And Hypex/Purifi have very deep and fast negative feedback.
Unfortunately, I don't know any good test of this opinion, and usually zero negative feedback amps have very different distortion profile.
Yes the A-70 has negative feedback.
 
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a.dent

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Based on what you have described so far, all four possibilities remain: (a) you and your brother are both right, (b) you are right and he is mistaken, (c) you are mistaken and he is right, and (d) both of you are mistaken.

It is possible that you and your brother have come to rely on different cues to the perception of imaging / instrument placement, and your past disagreements about it speak to that. And it is possible that the linearity of the Accuphase amp with respect to (frequency-dependent) speaker conductance versus the nonlinearity of the March Audio amp, together with the steep impedance vs. frequency dip of the Magicos, leads to different perceptions by your brother and you (due to differing ears and auditory systems and history and self-learning/training). A "scientifically plausible explanation" would be helpful only insofar as warding against dismissing possibility (a) as implausible or highly unlikely.

That you and your brother disagree on the status of imaging of your system, as also considering the many arguments about "imaging" and "soundstage" on ASR and other forums, shows that you are dealing with a "subtle" effect, as opposed to a "gross" sensory effect. With a gross sensory effect, there is much less need for caution in drawing conclusions, and indeed we could not function in day-to-day life without trusting our senses.

When it comes to subtle effects, the fuzziness of the limits of perception and the enormous complexity, inconstancy and variability of auditory perception are some the reasons why the war between subjectivists and objectivists will never end (the enormous suggestibilty of brains being another major reason). The previous responses to your OP have listed a large number of possible confounding factors, among them possible bias inherent in sighted testing. So far, both you and your brother have judged based on sighted testing which is vulnerable to psychological bias leading to biased perceptions. I can believe DBT is a PITA, and I am not suggesting a DBT by either of you (far easier to just agree to disagree), but if done it would help remove some confounding factors when it comes to subtle perceptions. As things stand, it seems to me that it would be methodologically questionable and premature to pick possibility (a) over the others, even if one could come up with a scientifically plausible scenario for it.
Yes I think we need to do a blind test.
It's difficult having to disconnect the speaker wires and change amplifier but I'm sure we can manage it.
 

antennaguru

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I'm not sure that Negative Feedback affects imaging/soundstaging very much, if at all. The main system in our mountain house has has gobs of Negative Feedback in the Op Amp filled preamp, Op Amp based tone control unit, and in the IcePower based power amp. That system uses wall mounted Anthony Gallo Acoustics Strada2 speakers with their matching subs, which many would say that wall mounting is bad for imaging, yet those speakers totally disappear and are replaced by a precise soundstage of musicians. The soundstage is not as expansive as on my No Negative Feedback reference system because the speakers at our mountain house main system needed to be installed closer together - but within that narrower soundstage everything is precisely presented. Depth of image and image height are there as well, although less so than with the reference system - which I believe has more to do with room layout, speaker setup, and the narrower soundstage. Expansive depth and height would be unrealistic relative to the narrower soundstage width. It seems that you shrink the soundstage width and the other soundstage dimensionality appropriately shrinks as well.
 
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SIY

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Does it have negative feedback?
There is an opinion that NF slightly blurs small details and makes imaging worse.

There is an opinion that psychics can use telekinesis to bend spoons. Just as likely.

I'm amazed at the superstitions around feedback, but perhaps that's because, ooooh, it uses math! As with most other ridiculous audiophile superstitions, I believe most of them originated with Jean Hiraga.
 

LTig

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Does it have negative feedback?
There is an opinion that NF slightly blurs small details and makes imaging worse. (I.e. correction is applied after signal already released, like small echoes, so ...) And Hypex/Purifi have very deep and fast negative feedback.
This! An opinion is not a fact, hence it should be viewed with great suspicion, especially here on ASR.
Unfortunately, I don't know any good test of this opinion, and usually zero negative feedback amps have very different distortion profile.
So this opinion is not based on facts and therefore should be disregarded.

There is however a science based explanations why power amps with low or no feedback (LNFB) can sound better in a level matched blind test where the level match is done using a 1 kHz sinus signal. Those power amps suffer from a too high output impedance - too high means that the resulting change of the frequency response (FR) of the connected speaker due to its non constant impedance curve becomes audible. If you look at such impedance curves typically you'll notice one or two peaks in the low bass and a rising curve in the highs (2 way speaker). The resulting FR will show more bass and more highs (compared to the mids), not unlikely a slight loudness curve. Of course such a combination will always sound better.

You can get the same FR with a power amp with high negative feedback (HNFB) , either by applying a loudness EQ or by adding a resistor of 1 to 4 Ohm in series to the speaker. If you do this the HNFB poweramp usually wins because it has less distortion than the LNFB power amp.
 

jtgofish

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I'm not sure that Negative Feedback affects imaging/soundstaging very much, if at all. The main system in our mountain house has has gobs of Negative Feedback in the Op Amp filled preamp, Op Amp based tone control unit, and in the IcePower based power amp. That system uses wall mounted Anthony Gallo Acoustics Strada2 speakers with their matching subs, which many would say that wall mounting is bad for imaging, yet those speakers totally disappear and are replaced by a precise soundstage of musicians. The soundstage is not as expansive as on my No Negative Feedback reference system because the speakers at our mountain house main system needed to be installed closer together - but within that narrower soundstage everything is precisely presented. Depth of image and image height are there as well, although less so than with the reference system - which I believe has more to do with room layout, speaker setup, and the narrower soundstage. Expansive depth and height would be unrealistic relative to the narrower soundstage width. It seems that you shrink the soundstage width and the other soundstage dimensionality appropriately shrinks as well.

In my experience having owned amplifiers with variable negative feedback the amount applied certainly changes image perception.Too much and the soundstage shrinks back towards the speakers.Applying too little can also cause other problems like a loose or boomy /underdamped bass.That is the problem with a lot of SET amplifiers that use no negative feedback..Great imaging but poor bass definition and control.Finding the right amount of negative feedback is the problem and that might vary depending on the recording and most especially on the impedance curve of the speaker.
In an ideal world all speakers would have a perfectly flat impedance curve of 8 ohms but speaker manufacturers have been allowed to get away with making speakers that have excessively low and excessively variable impedance.
 

LTig

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In my experience having owned amplifiers with variable negative feedback the amount applied certainly changes image perception.Too much and the soundstage shrinks back towards the speakers.Applying too little can also cause other problems like a loose or boomy /underdamped bass.That is the problem with a lot of SET amplifiers that use no negative feedback..Great imaging but poor bass definition and control.Finding the right amount of negative feedback is the problem and that might vary depending on the recording and most especially on the impedance curve of the speaker.
IMV the amount of negative feedback needs to be set by the designer and should never be adjustable - it's to delicate to leave it to customers playing with it. To high and you may end up with an unstable or oscillating amplifier, too low and gain gets too high and distortion out of control.

I noticed that a recording which I own in both vinyl and CD has different soundstage: the vinyl is somewhat wider but shows less depth (wall of sound) than the CD. I like them both but whether it's the higher distortion of the analog chain or differences in mastering I don't know.
In an ideal world all speakers would have a perfectly flat impedance curve of 8 ohms but speaker manufacturers have been allowed to get away with making speakers that have excessively low and excessively variable impedance.
This is because it's not easy and expensive to compensate the peak of the woofer (and port) resonance peaks - you'll need large caps and coils and yet the peaks may change with temperature and air pressure so much that the compensation must fail. Compensating the impedance rise caused by the voice coil is rather easy, you just need a cap and an resistor and the inductance is rather stable.
 

SIY

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In my experience having owned amplifiers with variable negative feedback the amount applied certainly changes image perception.Too much and the soundstage shrinks back towards the speakers.Applying too little can also cause other problems like a loose or boomy /underdamped bass.That is the problem with a lot of SET amplifiers that use no negative feedback..Great imaging but poor bass definition and control.Finding the right amount of negative feedback is the problem and that might vary depending on the recording and most especially on the impedance curve of the speaker.
In an ideal world all speakers would have a perfectly flat impedance curve of 8 ohms but speaker manufacturers have been allowed to get away with making speakers that have excessively low and excessively variable impedance.
No level matching and peeking- recipe to end up with nonsensical conclusions. Level-match, ears only, otherwise you're playing make-believe.
 

jtgofish

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No level matching and peeking- recipe to end up with nonsensical conclusions. Level-match, ears only, otherwise you're playing make-believe.
Of course.
 

antennaguru

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In my experience having owned amplifiers with variable negative feedback the amount applied certainly changes image perception.Too much and the soundstage shrinks back towards the speakers.Applying too little can also cause other problems like a loose or boomy /underdamped bass.That is the problem with a lot of SET amplifiers that use no negative feedback..Great imaging but poor bass definition and control.Finding the right amount of negative feedback is the problem and that might vary depending on the recording and most especially on the impedance curve of the speaker.
In an ideal world all speakers would have a perfectly flat impedance curve of 8 ohms but speaker manufacturers have been allowed to get away with making speakers that have excessively low and excessively variable impedance.

That sounds about right with SET tube amps, but I don't own any of those as I frankly never liked them. My experience is indeed different than yours vis a vis feedback. On my reference system, which images very well due to room setup, my no negative feedback solid state amp has the best bass and transparency compared to a negative feedback solid state amp and a negative feedback tube amp that I also own. All three amps image very well and there are only very slight soundstage differences, and all three amps are also tonally very similar.

I think the room setup is the most important component, having the greatest impact on imaging, but your mileage may vary.
 
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