[Mr Rick]

I'm getting tired of reading about amplifiers that have "better" soundstage.
 
What measured parameter of an amplifier indicates / dictates width of soundstage??

 

[mindbomb]

crosstalk, but there is no standard for the measurement, so you can't even compare specs of different products.

 

[Mr Rick]

  crosstalk, but there is no standard for the measurement, so you can't even compare specs of different products.

 
Schiit quotes crosstalk specs.

 

[jcx]

crosstalk is easily measured, likely seldom audibly significant - some "gaming" of the numbers or measurement conditions to watch for are:
 
the output loading (should be loaded as in use),
frequency (should be a full sweep)
and where the "output" is measured (outside the amp after TRS and with loading is what the consumer hears - probing inside the amp before the TRS gives better numbers)
 
its not hard for electronics to give ridiculous high crosstalk rejection numbers, more rejection than any open, many closed back headphones acoustic leakage coupling around your head
 
most music is mixed in listening rooms over speakers - lots of natural crosstalk
 
in analog days vinyl production it was determined that pretty much anything over 20 dB crosstalk isolation between R,L was adequate
 
you can hear lower levels than that on say iem with test signals - but its unlikely that even 40 dB crosstalk rejection is needed for "transparency" with music
 
 
anther maybe useful thread: http://www.head-fi.org/t/775303/soundstage-what-is-it-really
 
for an engineer the looking at amps is a ways down in the list of thing important to soundstage

 

[Mr Rick]

Isn't soundstage much more a function of the mixing process, and to a lesser degree headphone design?

 

[castleofargh]

  Isn't soundstage much more a function of the mixing process, and to a lesser degree headphone design?

I think he meant that if you have a crosstalk of -90db in a system, chances are that the sound from the left driver will reach the right ear and be louder than that.
the headphone cable might also change the crosstalk, at least in a measurable way.
and in fact the headphone's impedance will also change the crosstalk value of the amp(because of the change in current draw I imagine?), so you can't just rely on 1 value and certainly not as jcx said, on unloaded crosstalk value.
 
my lowfi newbie testings led me to conclude that crosstalk needs to be crazy bad to even be noticed. and when it is, it actually doesn't make the soundstage to really collapse, my feeling was more what is often referred to as getting the instruments "glued" together.  IMO it's a spec that really doesn't relate properly to a feeling of soundstage as soon as it's better than -40 or -50db(no matter how counter intuitive this seems).
 
 
 
I'm afraid no amp spec (at least not those usually offered) can relate to soundstage. soundstage is a mind construct based on a great many different cues, and often the interaction between those cues is as important than the cues themselves, as the brain use one to confirm the other and stuff like that. and it goes as far as mixing with vision in real life(where vision is trusted and used far more than hearing), so really hard to put one measurement on the line here.

 

[rolph]

  I'm getting tired of reading about amplifiers that have "better" soundstage.
 
What measured parameter of an amplifier indicates / dictates width of soundstage??

High frequency response + THD. Clearer response  = wider "soundstage". This is so because of anatomy of our hearing.

 

[castleofargh]

 

  I'm getting tired of reading about amplifiers that have "better" soundstage.
 
What measured parameter of an amplifier indicates / dictates width of soundstage??

High frequency response + THD. Clearer response  = wider "soundstage". This is so because of anatomy of our hearing.

I'd like to agree with this on principle, taking the objective logic. if the signal has higher fidelity, it will give better soundstage because closer to what was recorded.  and I have a few arguments in favor of that idea.
but then vinyls!
they deliver some of the worst fidelity specs you can think of, yet hard to argue that you can get a pretty great soundstage from vinyls. personally that's what makes me doubt the hifi approach of soundstage.
and even at the amp level, I've heard some very colored tube amps that felt like they had a great soundstage. yet those guys didn't need to be measured to know they sucked at fidelity.

 

[ProtegeManiac]

  Isn't soundstage much more a function of the mixing process, and to a lesser degree headphone design?

 
If the recording was properly done but then you play it through a system with very high crosstalk, then the soundstage won't come out properly. At the same time, it's not just amp crosstalk but overall response - if you have very high bass boost for example then there's a tendency to hear the bass drum coming from a point too far forward instead of behind the vocals.
 
That said, as much as the amp (or the DAC) can affect soundstage, and asuming you are using good transducers, you still have the limitation of what happens when the soundwaves leave those transducers. In a speaker system you have to manage reflections and dispersion patterns, otherwise you might for example hear the cymbals way out to the flanks near the guitars, which is only possible if the band was made up of The Fantastic Four with Reed on the drums showing off his stretchiness. The same thing is the bane of headphone listening but for a different reason: left ear can't hear the right transducer, on top of which the drivers are firing at an angle that you don't position actual speakers at (ie directly over the ear canal), and you can have teh cymbals and guitars right outside your ears, the vocals in your forehead, but the drum roll goes from extreme right to center to extreme left with nothing in-between. A lot of people I've noticed recently think this is "wide" soundstage as opposed to the reality that it's an incoherent one. I'd rather use Crossfeed (which is essentially selective and strategically designed crosstalk) for a coherent albeit "narrow" soundstage rather than an incoherent and unrealistic one, unless of course I can believe that Reed Richards is a drummer.
 
He's gonna put the cymbals far away and show off how he can hit them there.

 
 
And here is a photo of their vocalist, Sue Richards, who can't be located in the soundstage.

 

[rolph]

 
I'd like to agree with this on principle, taking the objective logic. if the signal has higher fidelity, it will give better soundstage because closer to what was recorded.  and I have a few arguments in favor of that idea.
but then vinyls!
they deliver some of the worst fidelity specs you can think of, yet hard to argue that you can get a pretty great soundstage from vinyls. personally that's what makes me doubt the hifi approach of soundstage.
and even at the amp level, I've heard some very colored tube amps that felt like they had a great soundstage. yet those guys didn't need to be measured to know they sucked at fidelity.

Exactly.
Human ear is focused to mid range there the human voice is. And those 12k+ Hz (harmonic reverberation ultrasound) noises you can't distinctly hear, but they make the environment feeling in your head.
 
Vinyls sounds better, because recording process on vinyl doesn't have dynamic range compression, so you hear more difference between in low and high frequency volume.

 

[jcx]

nice try, but digital audio can have less dynamic compression than vinyl - most vinyl was mastered from analog magnetic tape where "0 dB" was speced at 3% 3rd harmonic compression from tape saturation - and unlike digital "0 dB" in analog practice was really used as nominal with > +10 dB peaks allowed
 
loudness war compression is a choice - not a digital media limitation
 
 
on soundstage:
 

  the Smyth SVS Realizer is a practical demonstration that typical electronics don't seem to have a big problem with presenting a convincing synthesized soundstage of a specific set of loudspeakers in a real room
 
they sidestep a lot of the modeling with real measurements, mics in your ears in the real room, in front of real speakers from mono up to 7.1 multichannel setups and calibrate as you turn your head through specified range of angles for your personalized hrtf
 
then they do the same for your circumaural headphones - they supply a Stax Lambda system as a default for those without their own preferred audiophile cans and amp
 
the result is very good - you can localize the virtual speakers as well as the real, compare in seconds by just lifting the cans off your head, tilting them down so the head tracker can't see the target
 
the reductionist position is that good electronics, a complete ADC/DSP/DAC chain inserted gives "out of the head" stable, "realistic" soundstage of "those speakers over there, in this room" - because the phase, frequency response conditions needed for the amps ADC and DAC are trivial
 
http://smyth-research.com/technology.html
 
after hearing a full personal calibration demo of the full Smyth system in a 5.1 setup it is ROTFLAMO funny reading most Head-fi "soundstage" discussions of even headphones, much less claims that specific amps have a serious role in "correcting" soundstage, "in synergy" with certain cans
 
at least crossfeed circuits or plugins, Dolby Headphone make real differences - but still are pale shadows of what the Smyth Realizer does with personal calibrations and active headtracking

 

[Mr Rick]

So, bottom line. Two properly designed , state of the current art, amplifiers when used in blind testing will show no difference in soundstage. Correct??

 

[jcx]

several caveats apply to "all (good) amps sound alike" - but their do seem be reasons to believe it is possible if transparency, "fidelity" to the input signal and just amplifying it was the goal
 
in audiophile land some amps are intentionally not "transparent", have character, color - frequency/phase response not flat in the "conventional audio" range is the 1st order audible difference usually found

 

[Arniesb]

TUNING OF AMP have bigger or smaller soundstage!!! The brighter the more spacious!!! Just Like headphones that are brighter are more open and wider. I eq my HD650 HIGHS up a bit and result was wider, more open and airier soundstage. Most wide amps are bright!!! Just like Soundstage king K1000 are bright and HD800 are bright.

 

[icebear]

First of all there are a lot of different things going on in recording and mixing process. Multi miked, multi track recordings can pan certain instruments or singers into whatever position the sound engineer and producer deem OK. This for me is not what I usually listen to.
 
Then there are minimalistic recordings that try to capture the ambient sound of the band playing live in an actual acoustic space. Natural localization of sound sources basically relies on time differences between direct sound and reflected sound from the walls of the studio or concert hall. All these reflections and ambient cues together with correct timing will create the impression of a natural sound stage in a recording.
An amp (or any part of the entire set-up) needs to be able to produce all the tiny ambient cues at low level (aka "plankton") and needs to maintain the time differences as much as possible. I am not sure if there are any measurable parameters that can give cues if the amp will be able to convey a realistic sound stage. Maybe there are factors that are crucial to get the basics right but these alone won't determine a good or bad sound stage reproduction.
 
When I got my First Watt M2 and listened to "Friday Night at San Francisco" there was obvious ambient information about the performance space, extending left to right and way back. My better half was listening too, sitting at 90 deg. position to the left speaker, so not exactly what I would call sweet spot

. And just for the sake of verifying that the new toy was indeed better than my old amp. I switched the speaker cables back to the old amp and hit start again for the CD and my wife asked "What the heck happened just now? The sound stage completely collapsed!" And she is not familiar with any of the audiophile vocabulary...
 
To be fair the "old" was indeed 20 years old but an ASR Emitter I, so not too shabby either. It is in capable hands and most likely will get an overhaul job and fresh caps. Of course I can't measure these two amps for differences. I can just describe the audible differences.
 
Before this experience I have also been wary of these kind of descriptions but there was no second guessing, it was such a dramatic difference. To experience this you will need transducers that convey every detail that the amp feeds them and you will need to listen to recordings that provide enough ambient detail to begin with.