Room Correction! Does it help?

Discussion in 'Audio Hardware' started by thomaskong, Sep 16, 2018.

  1. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    Accuphase DG-28

    I had been using Accuphase Digital Equalizer since 2001.

    It is still working fine.

    With room correction, the overall balance is much better with tighter base and flat high frequency.

    [​IMG]

    I can not live without it.

    Recently Lyngdorf got very popular with good room correction capability.

    But I am a tube guy enjoying good timber out of it.

    I will not go for Lyngdorf as amplifier.

    But I recommend other people to try room correction.

    If you are curious, you can try used DG-28 from Japan at 1,700

    Accuphase DG-28 Digital Voicing Equalizer Free Shipping (R966 | eBay


    It use 100V not 120V so you may need transformer
     
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  2. qrarolu

    qrarolu Forum Resident

    Location:
    Stockholm, Sweden
    I have been using a Lyngdorf TDAi-2200 for the last ten years and, YES it works for me. Never had better bass, soundstage and tone. On the other hand my old Canton Digital room correction system never sounded right. If room correction works depends on the implementation.
     
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  3. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    I an happy with my Accuphase for 18 years.

    With my big space, room correction is essential.
     
  4. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    Room correction helps but it must be done with care. Standing waves in the bass can be reduced by notch filters. However, the room response target curve is not trivial since room reflections are also part of the natural response and expected to happen by our ear and brains.
     
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  5. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State

    I agree with you. Even with room correction equalization, deflector panels and some bass absorption traps are strongly recommended.
     
  6. Drewan77

    Drewan77 Forum Resident

    Location:
    UK/USA
    Yes, room correction helps but acoustic treatment wins. I use both.
     
  7. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    I am all for "room correction" in the bass / sub bass frequencies and find that it can help if you are limited in your speaker and room flexibility. It also serves a useful purpose when integrating a subwoofer.
    But it needs to stay away from midrange and higher frequencies where it introduces more trouble than it is worth.
     
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  8. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    I also try both. I agree with you.
     
  9. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    Not always

    Cheap analog equalizer degrade the treble sound but not good digital equalizer.

    With my Accuphase digital equalizer, I can get more airy sound with flat extension without degrading the quality.

    That is the reason that I had been using it 18 years, the longest period in my 40 years of audio history.
     
  10. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    I am not sure he refers to the quality, but that reflections are part of the room. You cannot correct for the diffuse sound without affecting the direct sound. So it needs to be done with care.
     
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  11. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    As an example, a white noise "room response" at listening position, measured at my system below. Although I sure should benefit to have a notch filter at ca 45 Hz to reduce the room node, I may also fix the dip around 300-400 Hz. But it does not sound natural (especially for the voice region 100-700 Hz) since this probably caused by floor or roof reflection. Secondly I prefer a ca 1 dB/octave slope in the curve due to the fact that in normal listening environments, the treble gets more absorbed than the lower frequencies (as Floyd Toole also writes). Third I prefer a lower energy in the 2,5-4 kHz region due to the fact that a phantom image in the center becomes more neutral; stereo speakers are situated in an angle and the direct sound should therefore be a bit reduced in the 3-4 kHz range. Peaking in this range is not recommended.

    [​IMG]
     
  12. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    im glad you enjoy your system . but once i hear any eq in the midrange and treble whether analog or digital i can spot the artifacts no matter how subtle they may seem.
     
  13. The Pinhead

    The Pinhead SLEAZY SOUTHAMERICAN CAVEMAN

    Room correction software is good but NO substitute for room treatments. Like the real cure vs. an aspirin.
     
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  14. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    Not quite!

    If your space is big, there is limitation with acoustic treatment.

    In that case, room correction make a huge difference on balance and details of sound.
     
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  15. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    Not sure what you are referring to when you say balance and details in large rooms. Do you mean that late reflections should be corrected for?
     
  16. jcmusic

    jcmusic Forum Resident

    Location:
    Terrytown, La.
    I used REW and the Xilica XP 4080 to correct my small room with great results, I also have Bass Traps and First Reflection Zone Panels!!!
     
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  17. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State

    Late reflections may not
    I had majored in Physics long 40 years ago so I can follow the terms.

    But in audio, the more important thing is the sound.

    During 80's, Japanese SS Amplifier boasted of .001 THD but with sound worse than 1% THD Tube amplifiers .



    I followed the instruction of Accuphase which showed the result before and after the correction.

    Frankly speaking I do not believe in their graph 100%.

    But I trust my year. I could get firmer bass and extended trebel after the correction.


    Audio is not the exact science but emotional art.

    If you put the speakers in anechoic chamber they sound bright without reverberation.
     
  18. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    It is good to have your valuable experience.
     
  19. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    There is no argue against preferences and also no argue against EQ to what your preference is. But that may or may not be related to room correction.
     
  20. Dillydipper

    Dillydipper Sultan Of Snark

    Man, you appear to have some significantly-unique challenges there! :eek: Is this a "listening balcony" (shooting a pic from your listening chair?), or is your optimal listening position intended to be downstairs?
    And, when you use your room correction...where are you setting the microphones, in relation to the placement of the system?

    I cannot imagine how many boom-traps you had to place, to make that work downstairs. :shrug:
     
  21. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State

    I have my listening chair in the middle of top floors about 12 ft from the speakers.

    Of course, I set the mike on top of my listening chair close to my ear.
     
  22. Dillydipper

    Dillydipper Sultan Of Snark

    Soooo...what DOES it sound like down below there?
     
  23. thomaskong

    thomaskong Well-Known Member Thread Starter

    Location:
    Washington State
    Frankly speaking , I do not care about the sound down below, since I listen to music from the listening chair on top flooer.

    It is just spreading to all three floors naturally.
     
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  24. Drewan77

    Drewan77 Forum Resident

    Location:
    UK/USA
    Expanding on the discussion about the impact of digital DSP (most specifically for the many people using subwoofers as part of their system but relevant anyway).....

    When I started using DEQX six years ago (originally to integrate a sub with the main speakers), I found that correcting raw frequency response, timing & phase has a significant & immediate impact on what I heard. Some of the issues we attribute to the room are actually as a result of poor native performance of the speakers themselves.

    If timing or phase are even slightly misaligned this accentuates certain frequencies in what we hear. I can give an example:

    (Background, not absolutely necessary to read....My 2018 setup uses two processors in a 5-way 2 channel setup. The main speakers are 3-way & were measured/corrected outdoors for the cleanest raw data. Measured again without moving after the DEQX algorithms did their stuff the speakers become razor flat with all drivers aligned from 50hz-23khz (freq, phase, timing). Likewise, each sub is corrected flat 10hz-250hz).

    In-room one processor manages the main speakers & the other the subs, they are linked master-slave. Although the speakers themselves are time aligned, new measurements from the listening position naturally show variations in frequency response and timing between the three (phase remained absolute across all individual drivers regardless):

    Main speakers 24.2ms
    Nearest sub 31.6ms
    Furthest Sub 33.8ms

    Adding 9.6ms delay to the speakers & 2.2ms to the nearest sub means all are then aligned to 33.8ms and the resulting sound is exactly right (& mighty impressive!). Because the room has bass treatment, first reflection wall & ceiling absorption & rear diffusion, the need for eq is minimal, only dealing with a couple of wider Q peaks below 100hz. I agree with other posts that digital room-eq is not recommended above about 250hz.

    However... if the main speakers are progressively delayed to greater than 9.6ms then bass starts to become increasingly erratic & by something around 16ms it is seriously strange. Likewise, If the main speakers are delayed by much less than 9.6ms, bass becomes thinner and weaker - regardless of anything to do with room treatment or eq correction.

    Understanding the complex relationship between speaker performance (especially timing & phase) AND the room is the main issue here - not JUST room correction or eq themselves. Correct the speakers & the need for any form of treatment reduces significantly.

    (...please feel free to be cynical about this until you have listened to a high-end and transparent DSP corrected setup, It is the ultimate game changer IMO)
     
    Last edited: Sep 17, 2018 at 4:13 AM
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  25. Thomas_A

    Thomas_A Forum Resident

    Location:
    Uppsala, Sweden
    One should also keep in mind that the DSP corrections in most cases cannot separately correct for direct and reflected sound unless you have speakers like the Beolab 90.

    (Preferences for sound is different topic. EQ is one way to get there.)
     
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