Digital Room Correction (DRC) discussion

Discussion in 'Speakers' started by philipmorgan, Jul 23, 2017.

  1. philipmorgan

    philipmorgan Member of the month

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    Seems to make sense to start a digital room correction (DRC) thread, so here goes.

    I was only recently able to set up an entry-level 2-channel system at home. I built an Overnight Sensations kit, added a Parts Express 10” subwoofer kit, and hooked up a JLH69 amplifier from Nobsound, a PLLXO from Parts Express, and a cheap-o Parts Express plate amplifier (for the sub) to my Gummy & Saga.

    This setup sounds pretty great for the relatively low investment. Just having the soundstage actually 6 feet in front of me vs. maybe a few inches outside my eye sockets is a dramatic improvement in terms of enjoying the music.

    @shotgunshane had some good things to say about the Dirac live DRC system, and that piqued my interest.

    At the same time my Raspberry Pi-based streamer was starting to get crashey and generally flaky, and I got gifted a Schiit Eiter. This perfect storm plus an unused 2011 Mac Mini made it possible to set up a computer-based media/streaming server. I’ve set it up with Audirvana+ (which I can remote control from iPhone), Spotify (also can remote control from iPhone), and Rogue Amoeba Airfoil (for when my wife wants to stream music to the Mac Mini via airplay).

    Enter Dirac live. I downloaded the trial software-only version on a lark to try it out.

    Daaayum! It makes a dramatic difference in integrating the subwoofer and improving the soundstage. I’ll try to add some more detail later in terms of room layout (VERY funky), speaker positioning (near field) and all that, but for now I’ll just say it’s all kinds of sub-optimal.

    Dirac live resolved a serious midbass peak, a lower midrange suckout, and some seriously 3-blob, flat imaging.

    dirac-1.png

    On my near-term TODO list are re-doing my Dirac measurements with greater precision, and cross-checking Dirac’s theoretical improvements with what Arta actually reveals in terms of before/after.

    Thus far Direct live software-only has been stable and adequately performant on the aging 2.5GHz i5 processor of the 2011 Mac Mini, but I really want to torture test it a lot more before I claim that it’s reliable (and before I throw down ~$450 for the license).
     
  2. Azteca

    Azteca Friend

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  3. ohhgourami

    ohhgourami Friend

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  4. MrTie

    MrTie Friend

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    I also recently tried the Dirac free trail, as I'm considering using a DDRC22D(https://www.minidsp.com/dirac-series/ddrc-22d) eventually pre-dac in a home system and wanted to see how well it worked. I gotta say as some one who has used various flavors of audyssey(XT & XT32) in my HT/Living room system that Dirac is a breath of fresh air. I really like how easy it is to use and adjust and target only certain areas of the response. Not sure I would pay $450 for the software alone, but it makes the MiniDSP products all the more intriguing to me.

    https://www.minidsp.com/products/dirac-series/ddrc-24 This one, if one is not concerned about the additional AD/DA conversion or wishes to simply use it in a smaller system as a dac/preamp/crossover, is literally as cheap as the software itself.

    Both can also be used as "black boxes" to keep the correction file outside of an active PC source, if one has another source(cd players, bluray etc) that would like to use.

    EDIT2: @philipmorgan I've also read and found that using the Couch setting(even if you have single chair, and aiming the mic in all position dead center between the speakers in every measurement position, really helps, which is much the opposite of audyssey. I did redo my measurement that way and found I got a better curve and correction, personally.
     
    Last edited: Jul 23, 2017
  5. philipmorgan

    philipmorgan Member of the month

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    That's really interesting. The ability to do my crossover in the digital domain if I got the DDRC-24 is super interesting. The price delta between the "big boy" minidsp boxes with Dirac and the same box without Dirac is about $400, so that makes me think the licensing fee to Dirac is about $400. I have no idea how they got the licensing fee to Dirac low enough with the DDRC-24 to price it at $450.

    Has anyone tried the DDRC-24? I don't love the idea of an extra AD/DA round trip, but the ability to do digital crossover is intriguing.

    @MrTie very interesting info about measurement technique. So to clarify, is the recommendation to still move the mic physically around, but to always aim it at the centerpoint between the speakers rather than aiming it straight ahead?
     
  6. JayC

    JayC Resident Crash Test Dummy

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    Yup, I concur with the second part of this. I got better results pointing the mic towards the center. This is what sonarworks recommends as well so I followed it while working with Dirac live.

    With regard to the couch vs chair setting - I preferred the chair. I felt that the overall result was similar but the bass was lacking some punch with the couch setting, while the chair was perfect and had a tiny bit better imaging too. I moved the mic around a bit more than what was pictured for the chair measurement though.

    Just fyi - the final response shown by Dirac
    [​IMG]
    isn't what shows up when you measure it all up with REW
    [​IMG]

    This applies for both, the frequency response and impulse response.. and although I've managed to get to a similar frequency response curve building my own filtered on REW, I've never been this happy with the result. This is possibly down to the impulse correction that Dirac offers, but I cant say for sure.
     
    Last edited: Jul 24, 2017
  7. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    I have miniDSP 2x4HD, which has the same hardware. It's a brilliant device versatility wise, but AD/DA stages won't be cream of the crop. One can use it as a USB DAC, which is a plus. I see no point of hooking it up to a DAC and would leave analog inputs only for phono duty.

    Overall I'd do DRC either in computer or pre-DAC so you get maximum transparency. Digital crossover/sub integration (both frequency and time wise) is also very interesting and yields good audible benefit. The perfect platform for that would be a box that allows for digital+analog input and up to 8 digital outputs (say 4xSPDIF). Sadly miniDSP offers no such solution, but it can be DIY'ed as SHARC DSP chip allows for 8ch I2S output.

    My hybrid solution is:

    RME ADI-2 Pro (AD/DA/DSP/Vol):
    1)Analog outs to main speakers
    2)Digital outs to miniDSP 2x4HD which provides DSP and DA to subwoofer amp

    It's not perfect as the ADI-2 Pro applies DSP to both digital and analog outs, so I apply HPF via main speakers themselves and LPF is done via miniDSP to bass. The advantage is that it's a very transparent solution which is able to run autonomously.
     
  8. MrTie

    MrTie Friend

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    Here's a decent little link/run-down https://www.reddit.com/r/audiophile/wiki/dirac

    The sections on calibration and target response have some good general info for Dirac.

    @Hrodulf Yeah I really really want MiniDSP to update the nanoDIGI like the MiniDSPHD with the nanosharc board and make a all digital 2in/8out Dirac and FIR capable all SPDIF/Coax box.
     
    Last edited: Jul 24, 2017
  9. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    im afraid room correction, when put into a system where listening position and speaker placement have not been optimized or room treatment not been applied, may make things worst rather then better. problem is we dont listen with the head at the exact same place where the mic was when the correction eq was applied and that the FR is not the worst problem, but the ETC and comb filtering caused by poor rooms.

    @ philipmorgan, as a test, after the room correction have done the EQ, can you post the measurements by moving the mic about 30 cm away from the location where the eq setting was based on?
     
    Last edited: Jul 28, 2017
  10. philipmorgan

    philipmorgan Member of the month

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    Will do, though it may be a week or two before that happens. I snagged @MyPetSasquatch 's DDRC24, so I'm going to re-configure my system around that when it arrives next week and then give some more details here on my room, measurements, and the off-target measurement you asked for.
     
  11. JayC

    JayC Resident Crash Test Dummy

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    Okay, since I last posted I ended up selling my Umik-1 and bought the Sonarworks mic and an audio interface. For some reason I am unable to use this with Dirac, but I've sent them an email and I'll figure it out over the next couple days.

    Here are my results from the Sonarworks page: [​IMG]
    Here are the results as per REW: [​IMG]
    Note the difference between the 3 measurements I took with REW. Two were from (very close to) the calibration spot with and without the correction profile and the third (in green) was taken completely out of the measurement zone (about 30-40cm to the left), and at a 45degree angle since @murphythecat asked for it. Note that this is the worst measurement I could get and thats partly because my room is pretty small (~12sq.m.)

    In general, comparing to what I had using Dirac and the Umik, Sonarworks' correction is more noticeable on the low end and to some extent, the mids. For some reason, Dirac made things sound really like a veil was lifted and was a really dramatic change overall. I wont comment about which I prefer until I've used the Sonarworks mic setup for Dirac as well so we're on a level playing field (and also until i've spent more time with them).

    I will say though that Sonarworks is definitely a better interface and the measurements are easier because its able to locate where the mic is and directs you to the next spot on screen. You cant make a mistake with it this way.
     
    Last edited: Aug 15, 2017
  12. NekoAudio

    NekoAudio Acquaintance

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    I've been a fan of the Dirac stuff for years, and I'm currently running the software on my computer and digital-only miniDSP units with Dirac. Still in the process of trying to get a breakout box for Dirac and multichannel audio from HDMI sources working—got some stuff on the way to try again as my previous attempts failed.
     
  13. murray

    murray Friend

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    I'm interested to know why you decided to sell the UMIK-1, as I was thinking about getting one for a first play with speaker/room measurement. Was it unsatisfactory? It looked like a cost-effective alternative to buying a preamp/ADC and a separate microphone.
     
  14. Grahad2

    Grahad2 Red eyes from too much anime

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    USB mikes do not work with Sonarworks
     
  15. JayC

    JayC Resident Crash Test Dummy

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    This is correct, and I think for the price of a UMIK-1, you could get the Sonarworks XREF20 mic and a cheap audio interface and have a better setup. I say this because, as @Hrodulf and others at Sonarworks explained to me, using the same device for both input and output eliminates any clocking differences compared to multiple devices so you get an accurate measurement. In the Sonarworks software, this also helps them locate where the mic is placed while making measurements. When I used the UMIK-1 with Sonarworks, the position of the mic drifted away and there was nothing i could do to fix it.
     
  16. Muse Wanderer

    Muse Wanderer Friend

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    What is the advantage of a Dirac box solution compared to PC based software only? I understand the issue with vinyl needing a separate AD/DA converter. However a PC based pre-Yggdrasil DRC may work for me.
     
  17. murray

    murray Friend

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    Thanks, I didn't think about the output device at all. Of course!
     
  18. Grahad2

    Grahad2 Red eyes from too much anime

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    If you are a PC only user, then there's no issue. Otherwise, it's convenient for every other source that is non-PC, like CD/DVD/BlueRay players, consoles, etc.
     
  19. pedalhead

    pedalhead Friend

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    Anyone had any success with AD/DA EQ for vinyl playback? My gut reaction is no no no...seems crazy to turn that analogue goodness into digital. But, I've just EQ'd my digital source and it's made a HUGE improvement in my room. I'm kinda tempted to try something like the miniDSP (although I understand the EQ channel count is pretty low). On the other hand, a Klark Teknik analogue EQ is a way to keep it all analogue, though you do give up PEQ in favour of their "proportional Q" which effectively decreases the Q-factor the higher the adjustment.
     
  20. JayC

    JayC Resident Crash Test Dummy

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    The DDRC-24 from minidsp could work: https://www.minidsp.com/products/dirac-series/ddrc-24
    I'm interested in @philipmorgan reporting back about it

    But yes, I have the same knee jerk reaction - that analog should stay analog. Things will not sound the same after converting back and forth, especially with something this cheap (the Dirac software ordinarily costs as much as the minidsp unit itself!)
    I enjoy my vinyl setup a lot without correction as is, even though digital sounds really good post correction. I'm hoping I can move away from DSP (atleast DSP that's this aggressive) with proper room treatment in the future
     

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