To crossfeed or not to crossfeed? That is the question...

Discussion in 'Sound Science' started by jasonb, Oct 21, 2010.
  1. WoodyLuvr
    Sorry, no idea but I do know that originally the plugin had a setting from 1-10 but then was updated by it's creator "Case" to have settings from 0-100.
  2. gregorio
    I really don't understand exactly what you mean by "spatial distortion". On all popular music genres (rock, pop, metal, electronic genres, etc.) virtually all the spacial information is artificial, and not an artificial recreation of some spatial reality but an application of reverb without even any attempt or concern for reality! The only concern when mixing and applying reverb to these genres is whether the result sounds subjectively good, not whether it sounds real or has any relationship to reality. In practise, pretty much all popular music mixes end up being a complete mish-mash of spatial information, simultaneously using several completely different reverbs; maybe a small room type reverb on one instrument, a medium chamber on another, a plate on another, an arena type left/right slapback echo/delay on the lead guitar and all this, all at the same time and probably all of them individually EQ'ed and processed so that even individually none of those reverbs would sound quite like a real acoustic space. And, this isn't a new trend, popular genres have been mixed this way starting in the 1960's, all modern technology provides is a relatively cheap and almost unlimited variety of reverbs and reverb parameters. So, "spatial distortion" relative to what? Spatial distortion is pretty much the ONLY spatial information on EVERY commercial popular genre recording for at least 40 years, if not 50 or more. So your idea of strong or not so strong spatial distortion is simply your personal perception of what is ALWAYS effectively 100% spatial distortion! Even with acoustic genres, such as classical music recordings, we virtually never have spatial information which could ever be experienced in real life. Starting in the 1950's setups such as the Decca Tree became one of the preferred methods for recording an orchestra, 3 semi omni-directional mics arranged in a triangle pattern with sides of about 1 1/2m (5 feet) placed roughly 3 meters above the conductor's position. You do not have 3 ears, they are not 5' apart and they're not 10' above the conductor! As time went on, outrigger mics and room mics were added to the typical setup and then later still, spot mics targeting individual instruments or small groups of instruments in the ensemble were added and mixed together with the Decca Tree or other mic array. You do not have 20 or more ears which are simultaneously placed all over the recording venue. Unlike with popular music, the mixing of classical music is taking at least some account for reality or rather, the perception of real/natural spatial information but in practise what's really on the recording is again a complete mish-mash of spatial information! The audiophile belief of "natural" and/or "real" is just an illusion, a deliberate and typically carefully crafted illusion but an illusion nevertheless, the only spatial information which is there in reality is always distorted! While it's flattering that our deliberate illusions are perceived as real or natural, it can also be rather disconcerting and we don't see this in other artistic fields. For example, in the film world, the equivalent of audiophiles are called "film aficionados" and they too have their own terminology and some pretty strange and erroneous beliefs about what really happens in filmmaking but unlike audiophiles, they realise films are not natural or real, that it's all a manufactured illusion.

    Yes, I completely understand that to some it's a very important hobby, possibly even, in some cases the only bright part of an otherwise, depressing part of their life. For me, it's somewhat different, it's not been an escape from or an addition to my real life, music and music/sound engineering is my real life, it has completely defined my entire life since my mid teens and I'm now in my early fifties. It's provided me with $500 a month for working 16 hours a day, seven days a week and for several years close to a million dollars a year income. It's provided me with amazing high points, amazing low points and some great experiences: Winning the world youth music festival in Vienna in 1982, performing in the Royal Albert Hall for the first time, playing the Rites of Spring with the Royal Opera/Ballet, controlling the sound for a full house at the Hollywood Bowl, being a BAFTA finalist, recording and working with some great stars, arguing with Malcolm Mclaren about music history and being backed-up by Brian May, threatening to call security on Dave Gilmour unless he put his guitar down, putting a $4m violin on the floor in a corridor without it's case, being complimented by Freddie Mercury, listening to Elton John trying to convince Robbie Williams he was gay but just didn't realise it (the funniest conversation I ever heard) and, holding a friend's head after a gig while he died from an overdose. Just a few of the numerous memorable (and repeatable) experiences which have made up my rather colourful life and although in some respects of the industry I'm a rather jaded cynic, in other respects I have at least as much determination and passion as I've ever had and there have been one or two occasions when that passion was the only thing which stopped me doing something terminally stupid. So, I understand more than most about the importance you're talking about! On the other hand, it's important to be open to facts we may not have fully appreciated previously and have a decent grasp of the difference between subjective preference and objective fact, something which can be difficult to achieve with music/sound recording and reproduction because it lies at the crossroads of art and science/technology and is routinely deliberately confused as a marketing tactic.

    Last edited: Dec 7, 2017 at 5:03 AM
    jgazal likes this.
  3. 71 dB
    Well, if you generate for example a 20 Hz tone playing in left channel only, crossfeed it with the plugin at levels 0, 20, 40, 60, 80 and 100 and recording the result, it could be possible to analyse what the relation is.
  4. 71 dB
    Let's say you have 12 dB of ILD at bass on your recording. If we look at measured HRTFs we see that such ILD can only occur if the sound source is pretty close to your ears. It seems improbable that the producers of the record intented that, kickdrums a feet from your head. How does kickdrum sound if you listen to it that close? It sounds insanely loud, but in the recording it isn't that loud compared to other sounds. If the ILD goes to 20 dB, the situation becomes pretty impossible, because the kickdrum is entering your ear to create such a massive ILD level, but kickdrums don't fit into our ear canals! They are ~100 times too large objects for that and if you had a miniature kickdrum that fits your ear canal, the spectrum of the sound it produces will be scaled 100 fold to some treble/bat frequencies. Kickdrums are expected to be located to some distance meaning ILD at bass is limited to a few decibels. When you listen to speakers, all of this is automatically taken care of by acoustic crossfeed. Headphones don't have acoustic crossfeed apart from the little leak of open models, so you have what I call spatial distortion, too large ILD levels. My opinion, not forcing on others...

    Yes, but our brain still has to make sense of it. Artificial becomes easier if you have cues from the reality such as reasonable ILD. My ears don't like large ILD below 1 kHz and for some reason scientific knowledge of human hearing does give explanations why (kickdrums don't fit into ear canals). But that's just me. I don't know how your ears work.

    I see it differently. To me acoustic crossfeed tames the excessive ILD levels with speakers creating ILD values that make sense. Crossfeed with headphones does similar (but not identical) thing. A hard-panned instrument becomes a spatially panned instrument with reasonable combination of ILD and ITD information. That works great for me.

    I don't get why acoustic crossfeed is fine, but electric crossfeed isn't. Both reduce excessive ILD.

    That is exactly why I need crossfeed to transform "Decca tree information" to something my ears and head understands. If they use say a Jecklin Disk then the spatial information is already compatible with my spatial hearing (spatial distortion free) and I most probably listen to the recording crossfeed off.

    I don't get why we shouldn't make spatial information less distorted. If a recording was clearly made for speakers (having acoustic crossfeed) and clearly sounds horrible with headphones without crossfeed then to me it's a nobrainer to use crossfeed, but that's just me… …it makes sense to me but apparently not to everybody. Maybe I just prefer my enjoyment of the music more than worshipping the hard panned fetishes of music producers 50 years ago. Yeah, could be that.
  5. 71 dB
    My life is the opposite of yours. 25000 euros a year working on something that doesn't interest me a bit under bosses with narsicistic/psychopatic characteristics or being unemployed as I am now. I don't even know what I want to do for living. Educate about spatial distortion? Nobody is going to pay me doing that, that much I know!

    Your background and working history just blows my mind. A couple of years ago I didn't even know who Brian May is until he played with Tangerine Dream and Googled that he is the guitarist of Queen. That's my reality. Your reality is to be backed-up by him. So different. No wonder our opinion differ too.
  6. pinnahertz
    With apologies...I know we've moved past this a little...

    In HRTF the above 1kHz effects are quite powerful. Yes, phase becomes meaningless as the wavelengths are too short, but diffraction and pinna effects are huge, and a major influence on virtual position and space. It's one reason why I've taken exception with your simplistic cross-feed circuit. In my personal research I've found that both ITD and diffraction are very, very important to cross-feed.
    Research means the same thing to me as it does to everyone else. Google the definition.
    What you've concluded is that your cross-feed is mandatory for everyone listening to headphones. Thats the part you have not proven. Research.
    No, that's not my point at all. Your work is not worthless. It's your conclusion and firm application that is flawed and unsupported. Research can be fun too.
    The smoking data was accumulated from a large number of tests, studies, and data that included millions of people. The conclusions were supported by that data, and thus authoritative warnings could be placed on packaging, and sales restrictions and sanctions applied. Yours?
    I strongly object to your incessant personal attacks and denigration. You have NO DATA to support your conclusions about my spatial hearing and NO DATA to support your insistence that your cross-feed is mandatory for all listeners.

    I Very Strongly object to your conclusions about my views on anything else! We haven't discussed global capitalism, and we aren't going to.
    Unsubstantiated claim.
    The cost is irrelevant if the claim is unsubstantiated.
    Irrelevant. Lots of software is cost free but accomplishes no benefit.
    The concept is supported, the need and desirability is not.
    Unsubstantiated claim. Big time.
    Research would return a statistical basis that in most cases results in some form of bell-shaped curve, including the strong preferences through neutral to the negative ones. Objective statistical analysis of subjective testing always returns a range of data, it's never fully polarized. Your list includes no negatives, no information about the total data-set size, really no information at all. A list of random, unverified opinions is not substantiation. We don't know anything about how these people were introduced to cross-feed, what biases were applied and still exist, what music they listen to, etc.,etc. Lacking any test information we must conclude it was fully biased, sighted and uncontrolled. You can get better than 50% preference for a placebo choice over an identical alternative under those conditions.

    You show fully cherry-picked and incomplete data. I've even told you I do like cross-feed on some recordings! You have nothing here in terms of substantiation of proof of preference, and that's not research.
  7. 71 dB
    Of course. The ILD problems are below 1 kHz and that's the frequency range crossfeed "fixes" while leaving above 1 kHz almost untouched.

    Crossfeed doesn't change pinna effects (doesn't change the shape of pinna). Sure, above 1 kHz channels are crossfed at a low level, but how is that even close to as detrimental even in theory than for example having headphones in you head changing the acoustics next to your ear even changing the resonance in your ear canal a bit? Headphones always give the sound from the drivers and you always have the diffractions you have. Move the headphones a bit in your head and the diffractions change. The change is pretty large at highest frequencies, but nobody seems to care. People only care about the theoretical microscopic problems of crossfeed. I don't say more to avoid insulting someone.
  8. bigshot
    I guess I'll stick with my speakers. This cross feed stuff sounds dangerous! Maybe cross feed caused those brain problems for the diplomats in Cuba!
  9. Strangelove424
    Doh, knew I forgot something!


    If I understand it correctly, DSPs higher on the list are processed first. You can experiment with different chain orders, and get different sounds. I found this chain sounded the best, and my logic for ordering them was to do EQ and tone correction first, then apply spatial processing with crossfeed.

    I just read your review of the TAL plugin, and followed your link to download the dll of the VST. I'm very excited to give this a shot right now. Thanks for posting your review.
  10. alex_aiwa_USA
    I'm just going to chime in and say I personally would never use a VOS plugin (Slick EQ in this case) for playback/listening. They're all wonderful plugins, but AFAIK all are deliberately designed to include various types of pleasant-sounding distortion beyond pure EQ. I actually haven't used this particular plugin though, do you know if you can actually disable all of the saturation algorithms?
  11. Strangelove424
    I think your missing the point. I use it for the saturation algorithms. I have graphic and parametric EQ for dedicated EQ plugins. I was inspired by this thread to explore saturation plugins and have been charmed by the effects under certain circumstances.
  12. pinnahertz
    Interesting. So you are correcting for hard-panned below 1kHz, but not correcting hard-panned above (I know it's a gradual transition). If I may...why not? Wouldn't hard-panned sounds above 1kHz be bothersome to you as well?
    They are not comparable, though. Both effects (overly wide separation) and HF response changes that are related to headphone position my be detrimental, but not in the same way. There's no means of comparison without statistical analysis of subjective testing, and I guess we won't go there.
    How would you know, though? Don't you reposition headphones for best (most pleasing) response? Each time you put them on? Some of us do that, and some of us do care.
    If that's really your belief, why continue to post? And how would you know what people only care about? Have you asked a lot of them, or are you just referring to one or two who post here because they disagree with you?

    I really don't think you've avoided insulting the targeted "people".
  13. WoodyLuvr
    Curious to see how you find it in comparison to your other saturation plugins.
    Do you use Replay Gain and/or Advanced Limiter?
  14. ironmine
    Music without a crossfeed sounds like a bee buzzing in the ear.

    This feeling is awful, weird and unnatural.

    Anti-crossfeed guys may say what they will, but it's not pleasant.

    It's not the way we hear sounds in the real world. If you listen to headphones without a crossfeed for a long time, yes, you may get used to it. That's what most headphone listeners have done, unfortunately - they have become accustomed to a wrong presentation of sound. That's why they resist.

    I am sure that 10 or 20 years from now, headphone listening without some sort of crossfeed would be regarded as an oddity, a thing of the past. It's like watching TV now in black & white mode.
    WoodyLuvr likes this.
  15. ironmine
    71 dB, thanks for your explanations and for the photo.

    I am not really knowledgeable in electronics, I cannot understand this diagram. If it were presented as a bunch of inter-connected VST plugins, I would understand it better :)
    WoodyLuvr likes this.

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