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Paper on Hi Fi Speakers and Room Response

Discussion in 'Room Acoustics / Isolation / Treatment' started by kmetal, Feb 18, 2016.

  1. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    andre linked this paper, and I thought it would be good to have over here, just for general interest.

    The discussion was based on 'house curve' where studios tend to have a response that has a boost in the lows and a dip in the highs.

    http://www.bksv.com/doc/17-197.pdf
     
  2. Sean G

    Sean G Well-Known Member

    Lol...I clicked on the link at first thinking it was about placing tissue paper over your NS-10s'.....Silly Billy :ROFLMAO:
     
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  3. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Lol. Bit more technical than that. My coworker will tell you the brand bob clearmountain used at the power station tho. The musical universe is a deep place.
     
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  4. Sean G

    Sean G Well-Known Member

    Kleenex I presume ?....I hear they Kleen up the sound quite a bit. :ROFLMAO:
     
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  5. Brien Holcombe

    Brien Holcombe Well-Known Member

    I would have to get Kurts' opinion on this document before I could take it seriously. I mean, the tests are using 20Hz as the low end cut off. Just because I could hear frequency in that range is not a valid reason to use it in the test, is it?

    I will just wait for further verification.
     
  6. Kurt Foster

    Kurt Foster Distinguished Member

    @Brian my thoughts are this paper is very dated. i'm not sure why you want my opinion. ???? o_O
    you're far more qualified than i to address the issue.

    is the paper advocating eq correction to address room anomalies? if that's so, i strongly disagree.
     
  7. DonnyThompson

    DonnyThompson Distinguished Member

    Scanning the paper, it appears as though that's what is being discussed. Although, to be fair, this paper was written for an AES convention in 1974; and the tests were done using five different speaker systems in a variety of "home" environments.

    Richard Allen's, Quad Elektrostat, B&O Beovox 3000, Wharfedale Super Linton's, and Isophon HSB's - (none of which I'm familiar with).

    As far as EQ "correction" as a method of translation - I've worked in many studios over the years that used a "master EQ" for "room correction", and I never liked mixing in those places; because the mixes just never really translated well to other systems.

    The mixes would sound okay in that room, maybe even good, but once they were played outside of that environment, there was always "something" off... and not always the common low-end issues , either. Many suffered from mid range and upper frequency problems, too.

    Side note: I can't say anything disparaging about Andre, as he always seemed to know his stuff. And, we don't know about the context in which he posted the link to this White paper, either; for all we know, he may have done so in an effort to use it as an example of how far room treatment has come since that time - remember guys, this was over 40 years ago...

    FWIW
    d.
     
  8. Kurt Foster

    Kurt Foster Distinguished Member

    the paper is written from an audiophile approach for listening vs. an engineering approach for a system suitable to tracking and mixing. audiophiles attempt to identify themselves with the recording community but they are listeners, not producers. the only things the two have in common is audio. the functions are at opposites. (i've put my flame suit on) :LOL:

    corrective eq only works at one very narrow spot in the room and is subject to any change in the space (a client moving around, a piece of gear being brought in, a pizza box , doors or windows being opened or closed ... )

    rta's are great at seeing the problems in a room. however the way to address them is not as simple as a little corrective eq. there is no magic bullet.

    proper
    studios are purpose built, installed in suitable spaces and treated to address residual sonic issues the room may still have. (we want to cure the illness, not prescribe a pain killer).
     
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  9. DonnyThompson

    DonnyThompson Distinguished Member

    Yup, you hit it on the head, Kurt. None of those listening environments mentioned in the paper - meaning living rooms, dens, family rooms - are using any corrective measures in the physical sense, although it seems to be more common today to see home theater rooms with traps, diffusers and BB absorbers. People seem to be a bit more hip to that stuff these days - meaning that they'll pay for the corrective measures - if that's what they are told that they need - but not that they understand the acoustic science... because most don't, and when you start talking to them about wavelengths and diffusion and nulls, they generally look at you like you're speaking Venusian. LOL

    Of course, none of the principles of acoustics have changed - 200hz was 200 hz in '74, as it is today, (and as it was in 1874, and 1774, etc.) and hot spots and nulls and reverberation in spaces have always existed; those things aren't new - LOL - it's just that in general, the "common" man wasn't aware of treatment methods in the time period that this paper was written; so they reached for corrective EQ/electronic solutions instead, which, as you mentioned, weren't really any real solution at all - other than for giving you a rough idea of what your room was doing frequency-wise. Those electronic "solutions" ( RTA EQ's, etc) also put quite a bit of money into the coffers of audio equipment and music store owners. ;)

    Perhaps some "audiophiles" were aware of traps, and diffusers and such, but I'm not sure that those who were ever went as far as to actually install acoustical corrective measures in their homes in those days... maybe, if the customer was loaded with money and wanted the newest, hottest "whatever" ... you know, "those" guys... ;)

    As I mentioned earlier, I usually never liked the mixes much that I did in studios where a "master monitor EQ" was in place - and for a few years there in the early to mid 80's, there were plenty of studios using that "balanced EQ" monitoring process; you would see a "master EQ" in one of the OB racks ( sometimes even in a storage closet) ; usually a dual 24 or 31 band, with an RTA function; sometimes even with the face-front of the EQ set behind Plexiglas so that the EQ faders couldn't be changed, either by accident or intentionally - but in my own experience, the mixes I did in those rooms just never seemed to translate very well outside of those particular rooms; and it wasn't always the "generally expected" low end issues, either... there were mid range and top end issues, too.

    I dunno, maybe it was just me. I'm just saying what I remember...

    -d.
     
  10. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    What I pulled from it were two things. Speaker placement makes a difference, and the room effects the speakers quite a bit, especially when they get small.

    Eq has its place in studios but it's the last 2% when all else is exausted.

    Rod Gervias book puts it well stating eq 'boosts the nulls'

    The paper is also interesting to me that most people subjectively liked the same speakers the majority of the time in a per room basis, and in the larger rooms there were very similar subjective choices across the board.

    Harmon still reccomends the same house curve.

    In all honesty my iPhone is probably as sophisticated as an RTA as theirs was, maybe not.

    Also interesting was the spl meter/plot point vs the RTA testing.

    I've done the radio shack meter / plot point (graph from Ethan winers site) and it came quite close to the REW wizard sweeps w the same meter.

    I'm not defending the paper on a studio basis because it's hifi in nature, but it does say something about the end listener.m and their enviornment. I think (I'd have to double check) two of those rooms meet the 1,500 cubic foot bbc reccomendation, which honestly I've always felt a bit small.

    I'd be curious to have some people subjectively hear mixes/eq curves on the ear buds and iPhones / androids, and see if preferences remain similar.

    As an aside I may get shot at, but I believe hifi is fun, and has its place in music. 10k 24 carat gold power cables need not apply in my rigs.
     
  11. avare

    avare Active Member

    I posted it (again!) in a thread where the Op asked if there is was a standard for frequency of systems. I replied with the B&K document including remarks that the recommended curve is for the speaker/room response. As someone else asked and then went off an major tangent, there is no reference to how the response is developed. Obviously, to us regulars here at least, the effect of the acoustics is significant. BTW the B&K curve fits within the EBU/AES/alphabet soup tolerances for system response.

    I hope this helps clarify points.

    Andre
     
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