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Internet sources on acoustics / digital room correction

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Just wanted to share various sources around on the net on the subject of acoustics and digital room equalization / correction (Digital Room-EQ ) that I have run into so far....

• I am sure I touched only a small percentage of what is around, so please feel free to comment & add as you see fit.
• I have not checked, read, verified or tested (let alone used) everything. Don’t shoot the messenger.
• I have no interest other than share info...

Papers / background / calculators / general

Room mode theory crash course: Acoustics Crash Course 1 - Modes

Room mode calculators:
Room Mode / Standing Wave Calculator | Calculators
Bob Golds

Acoustics Frontiers paper (must read!):


HTS: Equalization | Calibration at Home Theater Forum and Systems -

Measurement software:

DRC: DRC: Digital Room Correction
REW: REW - Room EQ Wizard Home Page
Audiolense: Juice HiFi
ARC: ARC System 2
Acourate: AudioVero
TrueRTA: True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software
FuzzMeasure: FuzzMeasure Pro 3
Ultimate Equalizer: Bodzio Software

Room Acoustics Measurement Tools For PC and Mac | Record, Mix & Master
The Well-Tempered Computer

Affordable measurement kit:

Mic: Behringer: MEASUREMENT CONDENSER MICROPHONE ECM8000 (get it calibrated)

Measurement kit + software / package solutions:

Dayton Audio: Dayton Audio Dayton Audio OmniMic V2
Acoustic Frontiers: XTZ Room Analyzer II Standard Acoustic Measurement Software Package | Acoustic Frontiers

Convolution engines (Convolvers; need to run ‘in’ or ‘under’ your player as a plug-in):

Convolver (windows) : Convolver — a convolution plug-in
JRIVER (windows): Native JRiver 64bit fp convolution engine for Room Correction (FIR filters)?
BruteFIR (Linux): BruteFIR
LAConvolver(Mac): Lernvall Audio
Fink - Package Database - Package jconv (Convolution Engine for JACK)
Mellowmuse IR1A - Zero Latency convolver RTAS, Audio Unit and VST plugin for OSX and Windows

Parametric EQ (no time domain, just frequency/amplitude):

apulSoft apQualizr : apulSoft - apQualizr (see comment Bob Stern)
FabFilter : FabFilter - Quality Audio Plug-Ins for Mixing, Mastering and Recording - VST VST3 AU AAX RTAS AudioSuite (see comment Bob Stern)

work in progress.... any comments welcome..

Updated 01-15-2014 at 07:35 PM by Lowlands

Personal Blogs


  1. mitchco's Avatar
    Excellent list! Here are a few others that I have come across:

    Room Correction: A Primer
    , by Nyal Mellor of Acoustic Frontiers
    Sound Correction in the Frequency and Time Domain, by Bernt Ronningsbak of Audiolense
    The Three Acoustical Issues a Room Correction Product Can't Actually Correct, by Nyal Mellor of Acoustic Frontier
    FIR Filter Basics
    Alan Jordan's Digital Room Correction Designer
    The Subjective and Objective Evaluation of Room Correction Products by Sean Olive
    What speaker and room correction is all about by Bernt Ronningsbak of Audiolense
    Acoustics/Treatment Reference Guide by gearslutz
    Savihost - a standalone VST convolver host
  2. Bob Stern's Avatar
    Bass EQ versus Room Correction

    People seem to use "room correction" to mean correcting frequency response and time (phase) alignment across the entire audio spectrum. This usually is implemented by "convolving" the audio signal with an impulse response.

    If you merely want to correct room modes and other frequency response irregularities below 200 Hz, parametric EQ is simpler to implement and easier to understand what's going on. I believe the DEQX products use parametric EQ rather than convolution.

    I suggest adding a Parametric EQ category to the above list. "apulSoft apQualizr" is a parametric EQ plugin (for Mac and Windows), not a convolver. Another parametric EQ plugin is "FabFilter" (for Mac and Windows). OS X includes its own parametric EQ plugin. In OS X, Pure Music can "host" any of these plugins.

    Also, Metric Halo DAC's implement parametric EQ in hardware with 80-bit arithmetic.
  3. Bob Stern's Avatar
    Convolvers for OS X

    All the convolvers recommended by the room correction software vendors require Windows or Linux.

    2 years ago I tried to find convolver software for OS X but lost interest in favor of parametric EQ. Some of you may want to explore two convolvers I found in addition to LAConvolver listed above, which has not been updated in several years.

    Jconv (free) for OS X 10.5 or 10.6:
    Fink - Package Database - Package jconv (Convolution Engine for JACK)
    Alan Jordan said: "Jconv does not act as a plugin, but has to run stand alone via a configuration file and then get routed via Jack OSX." Impulse response filter must be in mono WAV format.

    Mellowmuse IR1A ($50)
    Mellowmuse IR1A - Zero Latency convolver RTAS, Audio Unit and VST plugin for OSX and Windows
    AU plugin. Can be hosted by Pure Music.
    Impulse response file format must be stereo aiff.
    Latency is zero, so it must be implemented as an IIR filter. I assume this requires converting the impulse response to the frequency domain and losing the time alignment benefit of using a convolver (FIR filter) instead of parametric EQ.
    Alan Jordan said: "I can't speak to the quality of IR1A at this point, except to say that it sounds different than BruteFIR and Convolver VST."

    Quotes from Alan Jordan are from May 2010:
    RE: Feedback in case you convolve on a Mac - aljordan - Computer Audio Asylum
  4. Lowlands's Avatar
    Mitch, Bob,

    Thanks for contributing!