[neilvg]

IMHO there is something being left out in this argument that we need to consider. I myself, and I'm sure many others in this forum, have some experience with studio recordings and mastering houses. I've luckily been able to use some of the tools which are often used on today's records both for mixing, mastering and remastering. And here is what I have to say:

When doing some sort of enhancement (spatial, tonal, etc...) the 'electronic enhancement', is generally added on a very content specific basis. Especially when remastering a project, most engineers will actually do quite a bit of research as to the 'genetic makeup' so to speak of the actual recording and apply complementary, but modern day, processing that allows it to retain its original signature, but enhance those qualities lost in the translation, or somehow just simply lost or diminshed.

Let me give you one clear example of why this is important:
Let say you have a recording with a vocal that is panned 30 degrees to the left and a vocal image with a 1.2 ms delay which is panned 30 degrees to the right. The subjective experience would be a slightly fatter sound emanating from the middle of our sound field, but without a specific pinpoint. The part of the vocal performance that crosses over into each other's sound field (remember hard left and hard right are essentially like two completely different outputs, our ears do the combining in the case of music when heard together) will have a certain phase cancelation that in many cases actually serves the song or the vocal. It can actually thicken it up, or mask a particular trait (nasal vocalist, etc...).

Now let us say we apply a generalized crossfeed circuit which blindly takes the left data and puts it "in the right speaker" and puts the right data "in the left speaker". This will certainly be creating a large amount of undesirable phase cancellation. Whereas before this was a specific enhancement for the vocal, now it is being generalized and in a sense duplicated on on the other side of the field, thus effectively blurring the whole effect and god knows what else in specific situations. If you want listening pleasure, some performances can sound 'better' or 'different'. But many enjoy clarity and accuracy, along with good old wholesome fun, and thus, the circuit may not be for them.

Actually, you can perform, if so desired, the test yourself. Just take the output before and after the circuit and do a PAZ analysis on the waveform with your favorite Spectrum Analyzer using a C weighted curve.

Subjectively, I tend to hear more bass, but it tends to be a little "sloppy" and I tend to hear a dimished sense of clarity and imaging, and in turn I get a sort of warmth that allows me to jack the volume up a bit. In some recordings, such as old beatles records, the circuit is awesome and really helps, in other records (most records), it's simply makeup for poor equipment.

...my two cents on this one
Neil

 

[Dick Danger]

Quote:

Originally Posted by CRESCENDOPOWER I will give some of these designers of cross feed some credit, because they tried, but I hate to break the news to them, they failed, because all cross feed does is take away any advantages headphones have over speakers.

What advantages did headphones have over speakers to begin with? I've not spent much on my headphone system, less than $2k, but I've spent a lot of time at HeadRoom listening to their higher end equipment and I still have yet to hear anything from headphones that would make me ditch speakers.

To the original ? of this thread, try it, if you like it use it, if not, don't.

 

[neilvg]

Quote:

Originally Posted by Dick Danger What advantages did headphones have over speakers to begin with? I've not spent much on my headphone system, less than $2k, but I've spent a lot of time at HeadRoom listening to their higher end equipment and I still have yet to hear anything from headphones that would make me ditch speakers. To the original ? of this thread, try it, if you like it use it, if not, don't.

I don't know about you, but with the right equipment, headphone listening is TOTALLY DIFFERENT. (not screaming, emphasizing). For me, it is very very difficult to achieve the level of intimacy with the recording, the level of clarity, and the sheer almost sensuousness that having the sound completely cerebrally eveloping me creates. Now I know that speakers have many many benefits that headphones can't touch, the greatest being an unsurpassed soundstage and level of overall sonic realism. But to me, a good headphone setup is like taking a magnifying glass to a record and enjoying many of its more subtle and finer pleasures.

Neil

btw, headphone use in recording studios has long been used as a way to fine tune a mix. We will mix it first, and then go over it with the headphones in order to get some of the exact EQ'ing down, very subtle reverbs etc..., soundstage placement, vocal doubling placement, etc.. etc.. things that create more of an overall perception of the recording, but that would be very hard to pin down when listening to speakers.

 

[dknightd]

Crossfeed is, a sometimes crude, attempt at reproducing on headphones what you'd hear on speakers. I listen to a fair amount of music that was either recorded on microphones placed several feet apart, or, mixed to sound good on speakers placed a few feet apart. As described on the links above, when you loose the natural crossfeed sometimes an artificial crossfeed can help produce a coherant sound field. I've never heard of crossfeed attempting to expand the soundfield - if anything they tend to compress the soundfield from something that was designed to be listened to from two descreet souces many feet away from your ears, to something that is more suitable for listening with the reproducers only an inch or so away from your ears.
I'd be very interested to hear from somebody who likes crossfeed and who has tried several implimentations. I've only tried Jan's imlemantation, and on the whole I like it most of the time. It does a fairly good job of reproducing the soundstage of speakers on my headphones.
One thing headphones, even with crossfeed, can't reproduce is the localization of sound that the mind can perform by moving the head around. Headphones are stuck to your head, so, you can't expect moving the head to help with localization of sounds.
I'd like to see two versions of all music made availalbe - one for speakers, one for headphones. But that is not likely to occur, so IMO crossfeed on headphones is very useful.
But crossfeed is not crossfeed. Various implementations vary alot. I think when discussing cross feed we need to to say what we have tried. I suspect there are big difference between implementations. And there is no right answer, because crossfeed is trying to do something that is not really possible. I do think a complete bypass switch should be manditory on any attempt.

 

[rickcr42]

Quote:

When doing some sort of enhancement (spatial, tonal, etc...) the 'electronic enhancement', is generally added on a very content specific basis. Especially when remastering a project, most engineers will actually do quite a bit of research as to the 'genetic makeup' so to speak of the actual recording and apply complementary, but modern day, processing that allows it to retain its original signature, but enhance those qualities lost in the translation, or somehow just simply lost or diminshed.

modern day example of modern day recordings.not everything is that way nor has it been since the inception of recorded sound.Many recordings are no more than a special effect themself but intentionally so for a specific reason targeted to a specific audience.That does not invalidate them for eveyone though for most yes.
I still remember quadraphonics.No relationship at all to live sound though that is what the record labels and engineers of that time period would have you beleive.All "true" audiophiles of the era knew it was a gimmick and not valid but this did not prevent the sales of both the ecoded software,the decoding electronics or the additional speakers and amplifiers by teenagers who thought it was "pretty cool".
Next was an attempt to add articifial ambience by various means.Major corporations including AR (the main force).Rather than attempt to encode/decode some part of the live feel into the software it was decided to let the end user decide so eventually "machines" were offered to emulate what the demonstrations offered.Again not good.The all out demos using sixteen discrete channels would not translate into an affordable product using available technology at the time so what ended up in the home was no more than a glorified reverb tank.Used to add a very slight amount of rear ambience actually a "plus" with certain live recordings but a music butcher with studio recordings.
Some thinking person decided there was something to all this but the application was all wrong and Surround Sound in the home was born (even though available in some form in theaters for decades !).Now even the spouse would accept the additional speakers because MOVIES were made more realistic......but the music still not natural no matter what tricks used if the original content was not already there in a live recording.
You can manipulate content and have it work but not ADD content not there and have it come off so multichannel audio for music still not acceptable.My rig is totally passive/bypassable for both loudspeaker and headphone surround/ambience extraction.Nice with DVDs or video tape,rarely so with music though Frampton comes alive is one that is enhanced and so I use the L-R ambience extraction method.For me.

Crossfeed is like that in a way.Adding nothing to the signal not already there but attempting to restore something lost.That something is the natural interaction in real life of the left and right ear to sound events.If recording specific to headphone use you either use a dummy head and torso with omni mics where ears would be or your own head with mics mounted in ear buds to get a true realisation of the "space".Because the head is a brick wall to left and right signals crossing over to the other side the original recording must account for this from the start or in the end what you hear is not a real representation or the original.How can it be ?
Binaural done well is a damn scary thing and will have you looking over your shoulder to see who walked into the room.Being startled comes with the territory !If that is not real then the word has no meaning.
Artificially produced Binaural has a fair amount of that.Not the same but damn close.What surprised me most doing research on binaural emulators is the signal does not begin as a stereo signal for the sim but mono !
The rest of the signal is all HRTF (head related transfer function) and time manipulation (For a taste of "artificial Binaural" look to the Stephen King audio book "The Mist").
Again artificial enhancement.Adding something not there to try and make something "better" and this usually ends in failure because IT IS artificial and our ears/brains sensitive enough to now it ! Humans do not fool easily when it comes to directional cues when their eyes say something different.The brain sorts it out and discounts it and that is why we so often listen to music seriously with our eyes closed.
So the illusion of reality is not destroyed.Our brain KNOWS there is no orchestra in our living room.It would not fit ! But yet we can close our eyes and be transported to the original hall.
Fake ! not real ! Conning ourself ! All good

A signal meant ot have interaural crosstalk and is known that it will be played on a loudspeaker can be mixed to have a center,a left and a right image and that image on good equipment will be rock solid if the recording is a good one.But no way can the same be said for headphone listening.An analogy would be putting a wall up between the two speakers eliminating ALL left/right content from crossing over naturally.No Middle image !
I don't know too many who could live with that set-up so why not try to make headphones image like a natural sound instead of an artificially induced environment ?

Not for everyone and not perfect but a solution just the same....

 

[neilvg]

Well, for me, I tend to be agreeable (usually) with the crossfeed circuit with older style recordings (but not usually jazz) where the original mix may have been in Mono. The crossfeed really helps to develop a more natural headspace and staging for me. But when this is applied to more modern day multitracked recordings with all sorts of stuff going on, I prefer listening to it as unadultered as possible because things really tend to get muddy and other effects seem to come into play. I for one could care less for the crossfeed since good equipment overcomes, for me, any fatigue or awkward imbalances and staging effects. However, if it were to be an option, I think it would be a folly to not at least include a bypass toggle.

Neil

 

[Publius]

My short take:

There is nothing even remotely natural, or perfect, or realistic about headphone playback in the slightest, just like speaker playback is equally artificial. In this context, something as trivial as a minimal HRTF implementation (crossfeed) is probably going to be beneficial.

Anybody who tells you that 2 channel playback is some sort of paragon of purity probably hasn't listened to live music. It's good, possibly even better than 5.1, but it's no saint.

My experience: foobar's crossfeed filter is good. It does create a slight bit of low frequency cancellation which is honestly not bad at all and is always correctable through equalization. I can live without it though.

 

[Kirosia]

I personally can't stand crossfeed. I used to use it, but the novelty factor went away quick. I guess some people need it, others don't. YMMV

 

[rickcr42]

Couple of visual aids-


Why binaural is the only truly accurate technique reproduced with headphones (and sucks with speakers)Damn near a 1:1 transfer from mic to cans :

http://www9.dw-world.de/rtc/infotheq...o_rec1.html#k1

The Stereo signal :

http://www9.dw-world.de/rtc/infotheq...o_rec4.html#k4

Manipulated multimicrophone recodings.All those additional mics have to go somewhere and a decision made as to where.that will determine what earpiece gets what but the asumption is made there will be some interaural crosstalk and room refelection :

http://www9.dw-world.de/rtc/infotheq...o_rec8.html#k8

Or you have this :

http://www9.dw-world.de/rtc/infotheq...o_rec2.html#k2

 

[rickcr42]

From above reference page :

Quote:

[size=x-small]The main goal of a stereophonic recording is not to fulfil basic laws of recording techniques, but to realize the desired sound picture.[/size]

You can not have a "desired sound picture" be accurate for both loudspeaker listening and headphone listening.the requirments are just not the same.One has channel to channel natural crosstalk,the other a brick wall to that crosstalk.So you can and I plus many (most) others do enjoy headphones without a crossfeed network in the loop it is an attempt to solve a known problem through the minimum of electronics.in this case passive RC networks.Not an afterthought but a "corrector".
The old "if it isn't broke don't fix it" is off the list if something is not only broken,as many recordings are,but terribly so as in the case of many early stereo recordings.Damn near unlistenable with headphones if you value any kind of stereo imaging

 

[gpalmer]

Nice discussion, particularly Rick's commentary. There is one fallacy you keep repeating though Rick, that I find rather questionable. This is the idea that users "don't hear a difference" and that there is no change in the sound. You would have to posess some pretty serious hearing damage to not hear the reductions in signal quality introduced by the crossfeed implementations I've heard, which are the market leaders. Now whether you fond this less obnoxious than the dry signal not having the other channel mixed in is another question, the answer to which will vary by person. One which is interesting is the implementation on my Panasonic DVD-LA95. It will only work with 5.1 signals but it is actually capable of making the sound appear to come from the screen on most movies. It also introduces degradation though, it appears to cut off some frequency range and make things a bit muddier. The actual distortions introduced into the signal depend on the implementation of the crossfeed.

 

[rickcr42]

Quote:

This is the idea that users "don't hear a difference" and that there is no change in the sound

Not me man.I absolutly do hear a difference myself but I have read comments over time both here and other places where the statement is made by others they hear no change.I guess it just reinforces how different we all are.
What I hear is a widening of the soundstage even though you would think it would be the opposite plus some attenuation of the upper registers,some of the sparkle though not extremely so.
In those cases where I personally feel a need for a crossfeed the benefits of having a more diffuse and coherent soundfield outweigh any loss of the extreme upper octave detail.This is not an "in your face" signal modification nor should it be or the effects would be artificial sounding and the treble attenuation objectionable.More it is like taking off the grados and putting on the senns (as an example).Same music,same everything,different perspective on the sound.One i personally can live with for certain music and just about all TV/DVD listening with cans.

Normally I do not do the subjective type response and like to stick to the technical side and facts as i know them but for those who never heard a crossfeed circuit a more descriptive reponse on the sonics may help a bit.
Do others hear these things the same way as I do ? No clue.Subjective means person to person taste and system makeup will color any explanation so valid only to a point.
I also beleive explaining how something sounds is like explaining how chocolate tastes to someone that never tried it.I can say I like it and say why but they gotta take a bite before they will know if they like it or not.

****edit****


I really do plan to learn how to type one of these years if only to save on the editing time.Typing at the speed of thought is a no win if you think slow and type slower

 

[warpdriver]

I don't think anybody would say that crossfeed is transparent, but people like me use crossfeed from time to time find it a helpful tool for some recordings, and am willing to make the tradeoff to make the recording listenable in terms of headstaging.

I find I use it about 50% of the time, most likely to use it for studio mixed recordings that never had a soundstage to begin with. Sure it does affect spectral balance a bit inherent in the circuit design, but that is a fair trade to eliminate near discomfort from the "blobs of sound" effect. For naturally miked recordings, the crossfeed stays off for maximum fidelity.

 

[Lavalamp]

Thanks for everyone's posts.

I've decided to part up my crossfeed board and experiment before I case the amp up.

I will post my impressions.

 

[Nospam]

I haven't had a chance to listen to the various crossfeed implementations out there, but I do have one observation to make.

I have gotten to the point where I can no longer listen to early Beatles recordings with headphones. They seem to be the perfect examples of recordings that can benefit from crossfeed. I don't give a hoot if crossfeed degrades the sound quality... it can't be any worse than the totally unnatural channel separation that you hear with these songs.