Soundstage Width and Cross-feed: Some Observations
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Sep 21, 2014 at 12:07 PM Thread Starter Post #1 of 241

Andolink

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I've had the opportunity for the past 4 months to experiment with the addition of cross-feed to my headphone rig (see my signature).  In my case it's a custom designed 6 level balanced cross-feeder.  I'm extremely pleased with this major enhancement to my listening experience and I find several theoretical issues keep swirling around in my thoughts as I learn more and more about just what cross-feed does to the sounds I'm hearing through my headphone.  I'll address just one of these issues below.
 
First,  just so you know at least one of my biases up front, I'm a dedicated 2-channel audiophile.  I've never particularly enjoyed any surround-sound type home theater set up I've ever auditioned finding the multiple sound sources confusing and unnatural. 
 
I'm also aware of the rather strong negative view toward cross-feed in general among Head-Fi members and by the headphone gear industry as well, as is made obvious by the rarity of cross-feed implementation with either headphone amps or stand alone cross-feed devices such as mine.  (I had to have one custom made only because nothing like it exists in the marketplace that I've been able to find.)
 
So the issue,
 
First, there's no question that cross-feed does indeed narrow the width of the soundstage and this seems to be the primary objection to it's implementation by most listeners.  The more cross-feed, the narrower the soundstage until you reach maximum-- a mono signal. Cross-feed, in my experience, has no noticeable effect on the depth of the soundstage.  
 
The question that arises:  Is having the widest possible soundstage with your headphone gear always desirable as seems to be the opinion of virtually everyone contributing to Head-Fi?
 
I've come to the conclusion that the answer is definitely not. 
 
The first inkling I had that extreme soundstage width might not be desirable, indeed quite unnatural sounding, was when I got a chance to audition an HD-800 rig using the Decware Taboo MK II.  The accuracy and clarity were amazing to be sure but the extreme width of the soundstage was quite disorienting and unnatural to me.  
 
Using cross-feed these last several months has demonstrated to me quite clearly that this kind of presentation, where the sound sources are coming at your brain from so far around the sides of your head is not only contrary to what one hears at a live performance but confusing and disorienting to the brain in a way that is actually fatiguing over time.  I've noticed that adding cross-feed not only sounds much more like an actual live performance but is a much more relaxed presentation without the fatigue with extended listening.
 
No doubt all this is irrelevant to many of the genres of electronic music which deliberately use channel separation effects as a major element.  My listening however is primarily acoustic classical music and, of course, when I do listen to electronic music, I turn off the cross-feeder. 
 
I suspect that the generally negative views I've seen by most Head-Fiers to the idea of cross-feed stems from the saturation of our culture with the implementation of surround-sound in movie theaters and home theater set-ups.  For many, that dizzying effect of the sounds coming at you from all directions at once sounds normal.  It never has, though, to me.
 
I'm also well aware that cross-feed tends to diminish the micro-detail of the perceived sound signal in the same way that listening to loudspeakers does (i.e. the natural cross-feed heard by our ears in the absence of headphones).  Again, this is natural and realistic to me.  By analogy, one doesn't tend to appreciate a Picasso painting using a magnifying glass.  
 
Sep 21, 2014 at 12:29 PM Post #2 of 241
Nothing wrong with a little crossfeed, it's just a different experience. I personally don't use one, but I was "raised" on headphones so I'm used to their presentation. I like to feel like I'm in the middle of the music, rather than sitting in front of it. I don't really want to replicate a speaker sound, or even a live performance. I just want to replicate the music. I'll throw a DSP in occasionally if I'm listening to extremely channel separated music (I'm looking at you, Allman Brothers).
 
I haven't really noticed a widespread dislike of crossfeed. It seems to be generally more accepted than EQ. The reason it's rarely implemented in analog gear is partly because it's so easy to implement in digital plugins. And the people who wouldn't touch plugins aren't likely to play with even analog crossfeeds and EQ either. There have been a couple legendary amps that utilize a crossfeed circuit, the SPL Phonitor for example.
 
As for soundstage width: Accurate imaging >>>>> soundstage width. Sometimes I wish poorly mastered recordings weren't so in-your-face on my LCD-2s, but too much more and I'd lose that feeling of being in the middle of everything. Maybe I'll change my tune once I actually listen to a headphone with a big soundstage.
 
Sep 21, 2014 at 3:24 PM Post #3 of 241
like anything else, it depends on what you're listening to and your own preferences.
usually people actually refuse crossfeed because they notice changes in signature. deciding that no crossfeed is the "right" signature and thus refusing crossfeed for the same irrational reason that make people refuse EQ. as if the headphone was perfectly flat by default.
 
also a lot of people don't even think about imaging and with headphones they only really call soundstage, how wide on the sides sounds can be. then again these people will reject crossfeed as it reduces that axis(and they usually don't realize that crossfeed might have given a more 3D imaging on some songs).
 
 
and lastly there are those who simply don't notice any difference. when I got the leckerton UHA760, someone on its topic said he sold it to keep the cheaper UHA(not that it's a bad judgment call, they both sound super clean). one of his reasons was that he didn't hear any difference from the 3crossfeed positions available(2lvl+1OFF position) ^_^. as it's a good 50% of why I kept this amp, I can say that it certainly make an audible difference, as any crossfeed does. but that's how it is, that person can tell you all about differences from one cable to another or why one DAP is bad, but doesn't notice crossfeed...
 
when I bought a pico slim amp, despite sounding really fun for such a small amp, I was never fine with it because it had pretty much no depth. to me it was really annoying and I started to make mp3 files with crossfeed dsp as a way to solve the problem on my DAP. but someone else who had the pico slim never noticed until I talked about depth.
 
those are just 2 of many situations I've encountered, people simply don't focus on the same parts of music. also, listening to EDM clearly doesn't require crossfeed for me, I still use it, but it's not necessary. now listening to a some beatles songs is another story and I simply don't listen to them on headphones if I don't have a crossfeed.
most modern music is made thinking about headphones and doesn't abuse full left/right channels. older albums often do, because on speakers it was never a problem to have a singer on one side all song. 
same with gears, some will have some massive crosstalk already, so adding crossfeed might be too much a step toward mono.
and lastly, like Head Injury said, nowadays a lot of people are simply used to headphones and how they sound.
 
so crossfeed, good or bad? it depends ^_^. but I sure am happy to have some.
 
Sep 21, 2014 at 3:32 PM Post #4 of 241
For me, crossfeed just makes sense...and as you have explained, not using crossfeed can sound rather unnatural. I don't always use it though, it depends on the headphones used. 

For normal music, I use cross feed, but for binaural recordings, there's no need as cross feed is already implemented. For those reading, do a little experiment, take your left index finger, and block your left ear. Now move your right hand right up to your left ear and start snapping your fingers. That is what crossfeed does, it let's your right ear hear what is happening on the left...it's how our brains naturally process sound. So I guess it depends on what makes the sound sound sound better to you. Although, if crossfeed is poorly implemented it can sound quite unnatural too
 
Sep 21, 2014 at 3:38 PM Post #5 of 241
  Although, if crossfeed is poorly implemented it can sound quite unnatural too

This is probably part of my problem too. A few years ago I experimented with a handful of different plugins, and never quite found settings I liked.
 
This may be why a lot of people avoid both crossfeed and EQ. They're willing to spend thousands of dollars on audio equipment, but won't spare a couple hours to make it sound its best.
 
Sep 21, 2014 at 3:44 PM Post #6 of 241
  This is probably part of my problem too. A few years ago I experimented with a handful of different plugins, and never quite found settings I liked.
 
This may be why a lot of people avoid both crossfeed and EQ. They're willing to spend thousands of dollars on audio equipment, but won't spare a couple hours to make it sound its best.

Agreed. When I had the J3 I spent days playing with the EQ, and hours reading up on profiles posted by others online. I finally settled on what sounded best to me, and it sounded better than any of the "stock" EQ profiles. I understand the argument that having to EQ is annoying, but for the vast majority of headphones it simply MUST be done to get as close to a flat sound as possible. check my thread (http://www.head-fi.org/t/735341/what-is-an-audiophile-and-what-make-headphones-great) on what I have found so far to be the flattest, truest sounding cans so far. 
 
Oct 6, 2014 at 3:58 AM Post #7 of 241
To make sure, have you guys checked out the surround sound DSP software that has come out in recent years? Specifically, what do you guys think of the Dolby Headphone foobar config posted on this site? What about Razer surround? How would you compare those to regular crossfeed? Crossfeed, and surround sound processing are similar, but not the same. If you haven't tried out all the currently available surround sound signal processing, I suggest you do. My experience with them, is that they do not alter very much the width or depth of the soundstage, but they improve the stereo imaging, and lessen fatigue, like crossfeed (this impression is based on the average, but different software, no matter if it's called crossfeed or surround sound, will be made with different sonic goals in mind, and consequently will sound different). I also suggest trying the Out of Your Head software by Darin Fong, if you haven't already. That one seeks to simulate a wide variety of speaker systems using real measurements, and it has a very noticeable effect that will most likely impress you. In particular, I found a game of CSS with this on to be an interesting experience.
 
Oct 6, 2014 at 4:18 AM Post #8 of 241
  To make sure, have you guys checked out the surround sound DSP software that has come out in recent years? Specifically, what do you guys think of the Dolby Headphone foobar config posted on this site? What about Razer surround? How would you compare those to regular crossfeed? Crossfeed, and surround sound processing are similar, but not the same. If you haven't tried out all the currently available surround sound signal processing, I suggest you do. My experience with them, is that they do not alter very much the width or depth of the soundstage, but they improve the stereo imaging, and lessen fatigue, like crossfeed (this impression is based on the average, but different software, no matter if it's called crossfeed or surround sound, will be made with different sonic goals in mind, and consequently will sound different). I also suggest trying the Out of Your Head software by Darin Fong, if you haven't already. That one seeks to simulate a wide variety of speaker systems using real measurements, and it has a very noticeable effect that will most likely impress you. In particular, I found a game of CSS with this on to be an interesting experience.

My experience mirrors your comments quite a bit. Alot of people really seem to dislike Dolby processing, but I use it occasionally for movies. It makes my headphones sound exactly like sitting in front of my speakers. It's so uncannily similar, that I often think there is a mistake, and the sound accidentally got switched to my speakers, so I take the headphones off and then it's silent. I have no idea what they do with Dolby processing, but it makes the sound stage humongous  and yes, in my experience, can reduce fatigue, particularly when watching a movie and there's a lot of heavy sound effects.
 
Oct 6, 2014 at 8:00 AM Post #9 of 241
Curious that headphone listeners would talk about soundstage which is adjusted by the distance speakers are apart from each other.  Headphones make the soundstage a point inside the head.  I can't imagine giving the concept a second thought with headphones.
 
Oct 6, 2014 at 12:56 PM Post #10 of 241
Speaker placement can help spread the soundstage, but off-axis response is incredibly important. You can take two speakers with bad off axis response, but if you point them both forward without angling them in, you'll have a gap in the center of your soundstage.
 
Headphone soundstage is related to other factors, some of them housing-related and some of them frequency related. I'm thinking Dolby processing must apply a doppler-like frequency shift to the entire spectrum, making it sound more distant. I don't know why it's not worth additional thought though.  
 
Oct 6, 2014 at 1:21 PM Post #11 of 241
  Speaker placement can help spread the soundstage, but off-axis response is incredibly important. You can take two speakers with bad off axis response, but if you point them both forward without angling them in, you'll have a gap in the center of your soundstage.

 
A center channel fixes that right up. Too many people, even audiophiles put their speakers too far apart. The mains shouldn't be further than 8 feet apart, unless you have a center channel in which case you can double that distance.
 
Oct 6, 2014 at 1:35 PM Post #12 of 241
A center channel fixes that right up. Too many people, even audiophiles put their speakers too far apart. The mains shouldn't be further than 8 feet apart, unless you have a center channel in which case you can double that distance.


I can just barely lay between my fronts and I'm average height. The thing is, I couldn't put more space between them even if I tried. I have small floor standers but it's a small area. The sweet spot is only big enough for two. As long as you're in that spot though, it sounds great.
 
Oct 6, 2014 at 2:27 PM Post #13 of 241
   
A center channel fixes that right up. Too many people, even audiophiles put their speakers too far apart. The mains shouldn't be further than 8 feet apart, unless you have a center channel in which case you can double that distance.

 
Based on what listening distance? Or rather, which angles roughly are you recommending? Just wondering more about what your take on it is.
 
Oct 6, 2014 at 4:39 PM Post #14 of 241
Anything over 8 feet between speakers causes the phantom center to dip and disappear. It really doesn't matter how close or how far you sit. (But you can put the speakers closer together if you sit a little closer.) When you add a center channel, that allows you to do 8 feet on either side of the center to the mains. When the speakers are too far apart, soundstage disappears and you end up getting just the sound of two separate sound sources coming from either side. The width of the spread between the mains defines the size of the soundstage. A larger soundstage sounds more natural, because it is closer to human scale for the size of the performers playing the music.
 
Oct 6, 2014 at 7:21 PM Post #15 of 241
  Anything over 8 feet between speakers causes the phantom center to dip and disappear. It really doesn't matter how close or how far you sit. (But you can put the speakers closer together if you sit a little closer.) When you add a center channel, that allows you to do 8 feet on either side of the center to the mains. When the speakers are too far apart, soundstage disappears and you end up getting just the sound of two separate sound sources coming from either side. The width of the spread between the mains defines the size of the soundstage. A larger soundstage sounds more natural, because it is closer to human scale for the size of the performers playing the music.


I don't think you can support these ideas as general conclusions.  It is too dependent upon the particulars of a speaker's directional pattern at least.  I can think of two speakers right off that don't obey your idea of 8 feet.  One involved panel speakers as you might guess from my moniker.  At one time I had some Acoustat 2's and the room configuration and placement of doors meant I had to fire them across the short side of the room.  I ended up placing them around 14 feet apart and angled in perhaps 30 degrees.  I was only sitting about 6 feet from a line that would connect both speakers.  There was an unusually wide soundstage that had no hole in the middle at all.  You did have a very restricted area over which that worked, but it worked wonderfully.  Another was on three occasions hearing K-horns in very wide setups.  One had them about 16 feet apart, another around 24 feet apart and another something over 30 feet apart (it was a public club).  All had a well filled in soundstage with no problems in the center.  You did need to be a bit of distance from them, but in these situations that was the idea anyway.  I have heard a few other wider than 8 ft setups without a middle problem, but those sprung to mind.
 
If you deliver the right sound waves to the area of your head you will hear the right soundstage.  Now I do think a center channel is a big help in all this and would make many systems better.  Wouldn't even be much issue these days.  But it isn't the only way to get wide sound without a dead middle.
 
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