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  1. #51
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    What is an audiophile?
    _____

    In my spare time I occasionally surf the internet ...

    • Umlautica - Hear Hear!

    "I've been using DSP for more than 10 years now and here's what I've learned.

    TL;DR: placement > treatment > room correction

    Conceptualize is the schroeder frequency of your room. The schroeder frequency is where modal effects determine the steady state response at the listening position. Think of it as the crossover point between (a) the frequencies where the room modal effects dictate response and (b) frequencies where the direct response of the loudspeaker. It's typically 200-400Hz. This image helps explain.

    Consider DSP strategy as two logical categories:

    Loudspeaker correction: the nearfield, quasi-acoustic, direct magnitude response of the speaker.

    Room correction: primarily the frequencies below the Schroeder frequency of the room. It also will correct the room power as well.

    The room power response is different from the magnitude response of the system. The room power is what happens when flat on-axis loudspeakers bounces bounce sound around and have it absorbed by the room. This is what Harman found in steady state measurements.

    There's a saying that "you mostly hear the room". This usually omits that it mostly applies below the schroeder frequency. Above this frequency, the principal determiner of sound quality is the direct loudspeaker response. Below it, the room takes over.

    DSP is a great tool to have, it's not a panacea. Tools can be misused.

    For example, if your speakers have poor directivity (off-axis response), DSP cannot fix it. You can dump gain on a null and do nothing but add distortion and eat headroom. DSP cannot fix the null but it can help by taking some energy out of a peak from a room mode.

    Some generalizations of what to expect for correcting above the schroeder frequency:

    Bad on-axis: easy DSP gains - fire and forget

    Good on-axis with decent directivity: non-trivial DSP gains - use caution

    Great on-axis with good directives: difficult to improve with DSP - can't fix what isn't broken

    So if someone has JBL M2 towers, it's usually unreasonable to assume that full-range correction will improve things. It can do more harm than good. The M2 ship with an amplifier preloaded with DSP filters that provide a flat on-axis response.

    My ideal order of operations:
    Place subwoofer/speakers where room mode issues are minimized at the main listening position. For subwoofers, try the "sub crawl". Try midpoints of the front and rear wall. Try nearfield subwoofer placement. Try corners. Try everything until you're ready to find a new hobby. If you have a rectangular room, the REW Room Sim can offer tips.

    Set up your room treatment. To make a long topic short; first reflection points within ~5ms of path length, wideband treatment behind to reduce SBIR, and dispersion on the back wall.

    Use DSP to time align each subwoofer with your main speakers. The REW Spectrogram is a fantastic tool for this task.

    Set subwoofer gain to be a few dB above your main speakers.

    Experiment with the main/sub crossover point. If you have a room mode below 80Hz, it may help to center the room mode at the crossover point.

    Find what you prefer for toe-in of your main speakers. This depends on your speakers and boundary reflections. Get a friend to help. If you don't have any friends, try moving your head forward or back at your listening position to inform your next adjustment.

    Measure your loudspeakers using gated near-field measurements to find the direct response at the acoustic center of the loudspeaker.

    Use low-q filters to correct your loudspeakers to a flat response. Perfection is not the goal. Don't fuss with narrow dips. Save corrections below ~250Hz for room correction.

    Now you're ready for room correction!

    Run your favorite tool; DIRAC, Audessey, REW, GLM, etc. Be sure to take multiple measurements from multiple points to get an averaged spatial response. Correcting for one point in space almost guarantees that you'll make corrections that are worse for the space around that point.

    Be careful trying to extend your bass response below the natural response of your subwoofer. It can take more excursion or power than the subwoofer can provide.

    You may find that your room correction software performs best when low passed a little above the schroeder frequency of your room. Calibration can be limited to frequencies such as 20Hz-1000Hz like this. You also may find that a good target response follows the measured room response of the top octaves of your speakers.

    You may find that room correction sounds thin. Many prefer a 3-6dB bump around 50-60Hz helps fix this.

    Have fun with it. Try things. Have reasonable expectations."
    _____

    Is an audiophile a person ready to explore the multitude ways to improve his sound in his room? ...Like a scientist in search; by testing and measuring and analyzing data and ear listening and correlating and understanding and amelioring and gathering graphs and writings and observing and more testing and more listening and experimenting and discovering along the way.

    Loudspeaker's positioning in a room equipped with a hi-fi stereo sound system is one of them ... Jim Smith. No matter the music source (albums recorded on LPs, CDs, Audio Streams, R2R Tapes, V8, ...) @ 24, 48, 96, 192, 384, 768Hz.
    ~ Bob ~
    "And it Stoned me to my Soul" Van Morrison
    ClickAudiophile Audition
    Snoopy as the Red Baron attack
    Avatar = The Alan Parsons Project - Eye in the Sky (1982 - orbiting)

  2. #52
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Quote Originally Posted by u-sound View Post
    well, you dont treat your room and then add dsp on top.
    dsp is for a problematic room when you DONT treat it otherwise
    DSP is no substitute for proper speaker setting up. There's no point in buying costly speakers, then not bothering with getting them set up correctly and similarly there's no point in putting good speakers into an echo chamber of a room or any roon where no thought is given to carpeting and curtains, etc. Getting these right is far more rewarding than chucking DSP at the problem, hoping they'll go away!
    Sources - NAD M50.2 (streamer, CD player, CD ripper, hard drive music store)
    Amplification - NAD M33 all-in-one, NAD M12 preamp (in reserve), Atma-Sphere Class D monos
    Speakers - Avantgarde Duo XD, Avantgarde Duo (2006) - both aesthetically modified

  3. #53
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    OK, here goes. Jim Smith's "magic formula" for placement of speakers in relation to the listening chair is stated as 83%.

    Now, as I understand that, if the distance from each tweeter to the listener's ears (Y in his video description) is 100 units, then the tweeters should be 83 apart (X in his description). X divided by Y is the magic 83%

    I said I'd work out the angle this represented in degrees - ie the angle between lines drawn from the listener to the 2 speakers.

    My calculation is that this angle is ideally 49 degrees.

    If you need the geometry, here it is. By using an isosceles triangle with the base being the distance between the speakers at 83 units and the equal sides as 100 units, the angle between your ears and the 2 speakers is 49 degrees.

    Use a compass or protractor to measure your angle to see how well your speakers are placed compared with Jim’s formula.

    My own speakers are too close together, but unfortunately it’s not realistic to move my speakers about 2 feet further apart. Equally I’d have problems moving the speakers, or a huge L-shaped sofa (that’s over 20 ft long) forward 3 feet. I’ll have to be content with 68% or 40 degrees from my listening seat. Peter
    Attached Images Attached Images
    Sources - NAD M50.2 (streamer, CD player, CD ripper, hard drive music store)
    Amplification - NAD M33 all-in-one, NAD M12 preamp (in reserve), Atma-Sphere Class D monos
    Speakers - Avantgarde Duo XD, Avantgarde Duo (2006) - both aesthetically modified

  4. #54
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Where did the .83 number come from? I know it’s what Jim Smith recommends, but was it derived from some sort of calculation, or is just his preference? Apologies for being too lazy watch videos. FWIW, I’m at about .9, for no particular reason other than it works me.

  5. #55
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Quote Originally Posted by gordon View Post
    Where did the .83 number come from? I know it’s what Jim Smith recommends, but was it derived from some sort of calculation, or is just his preference? Apologies for being too lazy watch videos. FWIW, I’m at about .9, for no particular reason other than it works me.
    It comes from Jim setting up dozens, perhaps hundreds of rooms.

  6. #56
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    I don't see the point of calculating the angle, working with distance so much easier and accurate
    Moon 700i V2, YG Acoustics Hailey, Aurender N10, dCS Rossini, Oppo BDP103D (audiopraise board), Ansuz Mainz 8 D2

  7. #57
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    FWIW...

    I use the 83% as a starting point so that I don't lose time, especially after having voiced over a thousand systems.

    I was pleased when Wilson came out with their 1/1.2 set-up ratio years ago. 1 divided by 1.2 = 83.33%!!!

    If a set-up is having issues in a certain room, from time to time I will check the ratios to help me understand what might be happening.

    If others want to use other set-up info, more power to them! I hope it all works out for them.

    As recently as yesterday, I had a very knowledgeable and perceptive RoomPlay Reference client here for a listening/learning session, and like most visitors, it was the best system set-up he had heard. I'm talking about Musical Engagement, not audiophile sound effects...

    This with a system that costs less than the power cords from the last system...

    With all of these comments floating around, I did check the set-up - it was between 83.4 & 83.5%.
    DPT4ME - Dynamics, Presence & Tone for Musical Engagement; MBP (3) - stripped down for music only; Shunyata Omega & Sigma USBs; ISO REGEN w/short Curious USB links; Berkeley Alpha USB; Aqua La Scala II Optologic DAC; Schiit Yggdrasil - fully updated; Ayre Codex dac - updated; Pass Labs INT-60 integrated amp; Wyred 4 Sound STP-SE-2 preamp, Quicksilver Mono 120 amps w/Tung-Sol KT150s; Quicksilver Mid Mono amps w/Gold Lion KT77s; Fyne Audio 703s; Symposium Svelte Plus & Ultra Platforms; REL S-812 subwoofers; Duelund DCA12GA speaker cables; AV Room Service EVPs, Stein Music Harmonizers, Duelund DCA16GA & 20GA ICs; Shunyata Denali 6000S/V2; Tripp Lite PCs; Wyred 4 Sound power cords; AudioDharma cable cooker; dedicated custom room; various GIK & ASC room treatments; etc.

    www.getbettersound.com

  8. #58
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    I think if audiophiles did three things as a start to their system setup, they would be in very good shape.

    1. Pull speakers 5’ or more from the front wall
    2. Choose the listening position that has the smoothest frequency response under 250 hz
    3. Start with Jim’s 83% ratio for speaker placement and tweak from there by ear

    I don’t have nearly the experience that Jim does, but enough to know that this can lead to very engaging sound. I thank Jim for providing the guidance to help us all get there.
    Morgan

    NEW SYSTEM UNDER CONSTRUCTION

  9. #59
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Quote Originally Posted by MPW View Post
    I think if audiophiles did three things as a start to their system setup, they would be in very good shape.

    1. Pull speakers 5’ or more from the front wall
    2. Choose the listening position that has the smoothest frequency response under 250 hz
    3. Start with Jim’s 83% ratio for speaker placement and tweak from there by ear

    I don’t have nearly the experience that Jim does, but enough to know that this can lead to very engaging sound. I thank Jim for providing the guidance to help us all get there.
    #1 is questionable; either Wilson's or Jim's method should probably be used instead (FWIW my speakers are 58" from the front wall; 64" - where I started - is/was definitely too far out into my 23' room)
    Rob
    __________________________
    Tascam BR-20; Technics 1506 with tape path upgrades, FM head, DeHavilland 222 tape head pre; Modwright Oppo 205 full tube mod w/LPS; Euphony Summus server, EtherRegen, HDPLEX LPS; MSB Discrete DAC (dual PS, ISLPro, balanced out); Pass Labs XP-12, XA60.8 (pair); Daedalus Audio Apollo 11’s, VMPS Larger Sub; Daedalus/Wywires, Acoustic Zen, Sablon Audio, Wireworld, Shunyata Research cables; Core Power Equi=Power;
    Adona rack, ​​​​​Stillpoints, IsoPods, ASC, GIK Acoustics accessories

  10. #60
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Quote Originally Posted by rbbert View Post
    #1 is questionable; either Wilson's or Jim's method should probably be used instead (FWIW my speakers are 58" from the front wall; 64" - where I started - is/was definitely too far out into my 23' room)
    Jim definitely recommends pulling the speakers out into the room. I used the 5’ minimum suggestion as a basic starting point.
    Morgan

    NEW SYSTEM UNDER CONSTRUCTION

  11. #61
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    Re: Has Jim Smith discovered a magic formula for placing speakers correctly?

    Quote Originally Posted by rbbert View Post
    #1 is questionable; either Wilson's or Jim's method should probably be used instead (FWIW my speakers are 58" from the front wall; 64" - where I started - is/was definitely too far out into my 23' room)
    But this depends so much on the speaker type. Electrostatics vs horns for example require totally different setting up, particularly with regard to how far from the rear wall they need to be ideally placed. Eben sealed box vs rear ported boxes will be different. My Martin Logans were truly poor with too much space behind them, but my horns are absolutely fine with 12 ft behind one and 15 ft behind the other - or in fact pretty much anwhere, even close to the rear wall.
    Sources - NAD M50.2 (streamer, CD player, CD ripper, hard drive music store)
    Amplification - NAD M33 all-in-one, NAD M12 preamp (in reserve), Atma-Sphere Class D monos
    Speakers - Avantgarde Duo XD, Avantgarde Duo (2006) - both aesthetically modified

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Has Jim Smith discovered a magic formula for placing speakers correctly?

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