Realism and channel separation ...

[drummerman]

 

[drummerman]

I came across a fascinating article by Jim Lesurf in which he advocates using a 'cross bleed' resistor to reduce channel separation for added realism and a more natural image in stereo. Apparently, deliberate cross bleed is something certain Headphone amplifier designs include. The article was more about tone and in particular balance controls but I found the above intriguing.

I am not sure where imagery would rate in my hifi priority list. Whilst somewhat important it probably wouldn't be at the very top so I can see his point to an extend.

regards

 

[The_Lhc]

Surely the level of channel separation is entirely down to the recording mix? So this may help some recordings but ruin others? You might as well listen in mono if you're going to go down this sort of route?

 

[MajorFubar]

Not sure there's a straight answer because it all depends how a record has been mixed. Also, in a typical HiFi setup each speaker is heard by both ears, just like a real-life instrument. Headphones are different because each channel is squirted just to one ear.

 

[drummerman]

Surely the level of channel separation is entirely down to the recording mix? So this may help some recordings but ruin others? You might as well listen in mono if you're going to go down this sort of route?

No. Amplifiers, CD players etc, anything with a stereo output stage has channel separation, sometimes referred to as crosstalk. Independent left right channel design, from transformer to output is said to provide better separation. I am not so sure it is that 'simple' as there are examples of just such dual designs which don't measure that well (as are some that do). I think a good design is a good design, whichever solution it employs but I can see why the independent left/right ones are sometimes favored, especially in high end.

Sure, the recordings are the most important thing. What Lesurf was trying to say is that less is sometimes more, even in stereo and that he is willing to sacrifice a little left/right imagery to give a more stable centre image, a more focused sound for better coherence.

Bear in mind that certain phono cartridges have relatively low separation yet still give good imaging I guess the real question is just how much separation is needed ...

regards

 

[Thompsonuxb]

Er....no.....what you talk about is more to do with speaker positoning and distances than anything an amp will do or what any amp maker can engineer into their amps.( we are talking seperation in a 'soundstage...right?)

Example place 2 speakers directly side by side and you more or less get a mono sound stage - while place 2 speakers far apart and run a mono source through them and the depth of the mono image can be striking - big head in the room image.

And why would someone want to reduce the stereo image anyway - less is not more unless you only have one working ear then it makes no difference .....

 

[drummerman]

Jim Lesurfs article has nothing to do with speaker placement.

regards

 

[busb]

What Jim is suggesting makes perfect sense - particularly for headphone listening where there's little natural Xtalk. I've often listened to non-acoustic music where part of the mix only gets fed to one channel for short periods. Through headphones, the effect can be quite unpleasant for the opposite ear, especially if there's no ambient sounds to fill the void. With speakers, there's enough Xtalk to mask the unpleasant effect to some degree.

 

[Thompsonuxb]

I don't doubt that.... :rofl:

But the sound any amp produces requires a 'speaker' and with regrad realism and channel seperation positioning and distance of the speakers have real impact more than anything an amp maker can engineer into their amp.

Give us the link ......

 

[Thompsonuxb]

What Jim is suggesting makes perfect sense - particularly for headphone listening where there's little natural Xtalk. I've often listened to non-acoustic music where part of the mix only gets fed to one channel for short periods. Through headphones, the effect can be quite unpleasant for the opposite ear, especially if there's no ambient sounds to fill the void. With speakers, there's enough Xtalk to mask the unpleasant effect to some degree.

I'm not a big user of earphones, so not sure what you mean by the above regards the mix, in older recordings, when technology was not so great and the majority of the band came out of one channel and the vocalist the other is this the sort of thing we are talking about, to reduce the one or the othetr side type stereo?

 

[drummerman]

I don't doubt that.... :rofl:

But the sound any amp produces requires a 'speaker' and with regrad realism and channel seperation positioning and distance of the speakers have real impact more than anything an amp maker can engineer into their amp.

Give us the link ......

I would like to think that most people here know that speaker positioning has a large effect on sound.

It is still not what J. Lesurf is talking about. - You can shuffle your speakers closer together/toe them in more or whatever and get a more centralised image. The effect will not be the same as if the speakers are positioned 'optimally' and separation is reduced as described by the author. Any channel imbalance, a few percentage of a decibel can scew up the stereo image if great care is not taken. His way of doing it solves this to some extend and has other effects which could be benefitial to getting a more cohesive, enjoyable sound. Not everyone will agree on his way of thinking but thats why I've brought it up for discussion.

The article is in the July 2011 Hifinews edition.

regards

 

[Thompsonuxb]

Hmmmm, I have not read the article but from what you've just said I can't see anyone taking it seriously.

Unless the article is aimed exclusively at earphone amp listeners, no one sits rigid when listening to music, not at a concert or in the home. sorry I'll move on.

 

[drummerman]

Hmmmm, I have not read the article but from what you've just said I can't see anyone taking it seriously.

He is both an experienced Electronics Engineer with a life time experience in Audio and reads Physics and Electronics at St Andrew's University ...

... that doesn't automatically make him right but the people at HifiNews think its enough to give him a regular column and the Uni obviously thinks that he sometimes at least makes sense.

You move on pet.

regards

 

[busb]

What Jim is suggesting makes perfect sense - particularly for headphone listening where there's little natural Xtalk. I've often listened to non-acoustic music where part of the mix only gets fed to one channel for short periods. Through headphones, the effect can be quite unpleasant for the opposite ear, especially if there's no ambient sounds to fill the void. With speakers, there's enough Xtalk to mask the unpleasant effect to some degree.

I'm not a big user of earphones, so not sure what you mean by the above regards the mix, in older recordings, when technology was not so great and the majority of the band came out of one channel and the vocalist the other is this the sort of thing we are talking about, to reduce the one or the othetr side type stereo?

In my own experience, what Jim L suggests only really applies to headphone listening & where sounds are added directly to one channel almost exclusively which creates a "hole" in the other channel that makes the mix sound artificial. Well recorded electronically created music avoids mixing in a sound to one channel without bleeding a little into the other channel as well.

IIRC, adding a small amount of Xtalk adds to the illusion of depth without sacrificing the stereo effect significantly - both are important to giving a sense of space to a recording. So-called depth can be added with a little reverb to electronic instruments.

 

[drummerman]

I once had an Audiolab 8000S, the first incarnation.

Although memory is not exactly the most reliable preservation of impressions like these, it did bass well, imaged great and sounded very hifi if I remember correctly but I could never warm to it. It kind of tore music apart if that makes any sense. It was all there but didnt join, at least not for me. I guess it was probably fairly accurate, still ...

I had it for I think three months or so and changed it to an Audio Innovation Valve amplifier. It was easier to listen to, more 'together' yet almost without doubt, technically less accurate/accomplished. It almost certainly had less channel separation too.

Whilst I normally lean towards 'accuracy', ie. products that dont impose to much of the designers philosophy (or shortcomings) on the signal, at least to my ageing ears, I can see where Lesurf is coming from. Incidentally, he modifies his pre-amplifiers in this rather unusual way.

regards