How do you measure the acoustics of your control room ?

[joaquins]

SBIR is independent of the listening position, so using EQ to cut the excessive low freq peaks is not for a particular listening position. Also I do optimize the listening position over other, when you are taking the decisions you are sitting in the right spot, if not you are messing, you wouldn't take a decision sitting at the corner of the room, that would be insane.

JS

 

[ruairioflaherty]

Hi all,

A quick update.  I spent a very enjoyable afternoon and evening yesterday with UBXF at his studio.  It is a really nice space, large and with real potential to sound great.

I'll leave it to UB to go into detail if he wants to.  We spent maybe 30 mins out of 6  hours measuring, everything else was done by ear and with experimentation.  I would call what we did yesterday a first phase but there is something of a road map to keep moving forward.

Cheers,
Ruairi

 

[rob_gould]

Fascinating thread.

One question for all the pros posting in here...

Did you learn this stuff on the job? Did you study first to understand the basics? Or did you study extensively (maths, physics, acoustics) before working in this field?

 

[abbey road d enfer]

Fascinating thread.

One question for all the pros posting in here...

Did you learn this stuff on the job? Did you study first to understand the basics? Or did you study extensively (maths, physics, acoustics) before working in this field?

Some of us are formally trained, others are self-trained. In fact, becoming an expert in the domain involves a lot of self-training, since it's only recently that universities have created cursus specifically dedicated to electroacoustics.
As to math, it doesn't take much, but still requires basic geometry and trigonometry. Differential equations may help understanding the most arcane aspects. For example, you need to know differential calculus for analysing the behaviour of a microphone in diffused vs. free-field, but you don't need it to use them.
Physics are paramount.
And obviously acoustics, that can be learnt in many books.
I would say I've learnt 10 times more by reading books and experimenting than by the formal training I had in EE school, but that formal training was a big step.
I wouldn't speak for others, but I guess that would be the same for most our valuable members.
I believe that's the case with most successful professionals, whatever the domain.

 

[joaquins]

Fascinating thread.

One question for all the pros posting in here...

Did you learn this stuff on the job? Did you study first to understand the basics? Or did you study extensively (maths, physics, acoustics) before working in this field?

  The help in formal training for me is just to get the ideas or the concepts you should get deeper attention and experiment on, I did have some formal training at the university. Then playing around with a mic, a speaker, and few materials to try and analyze it's acoustical properties was quite important, in fact I made most my treatment with alternative materials I got for free, which is missing a lot yet because I didn't put enough time and I almost don't use my control room as such, in fact now is just a workshop. It wouldn't be useful for me to say which materials I used, you just need to find which kind of materials are good for each task. Think in glass wool for example, glass is quite heavy, but this has a lot of air in between, similar materials will work, cotton wool does work for example and quite good, isn't cheaper though but you can find cotton for cheap where they throw it, cloth factories for example.

I'd say read something, find a good book about acoustics you like and read it twice, I don't have any at the top of my head now but there are a few. Then experiment a lot, with what you have, you don't need a reverberant chamber, a bathroom without anything inside is usually good enough to measure some absorbent properties with acceptable error. You don't need a measurement mic, any will do, better if it's omni and condenser. In any case the Behringer ECM8000 is as cheap as a mic gets and really works for home "lab" use. This and a computer with some sound card with mic pre and software, which are some free available, you are good to go. Moving around the mic, moving around the speaker, comparing different absorbers, that kind of stuff really helps. I'd recommend to get a known absorbent so you can check how off are your measurements. You build your setup, measure one that you have the data sheet, then start working with experimental materials. For room treatment try moving around the elements you are using, changing the elements... It takes a lot of experimentation till you get to read what the software is saying how big or long a peak in a waterfall is problematic. Once you get that idea, you are in a better place and getting then again into a deeper theory start to make much more sense and you will see it much better.

JS

 

[rob_gould]

Thank you both of you.  Good insights...

 

[ubxf]

My introduction to the subject was mostly theory  with some observation of finished rooms in different studios. So i did calculations and applied that to my room . When it was done i could tell it wasn't right. Ruairi  very nicely offered to help, he brought his knowledge, experience and very good ears. Right away he knew the bass response was off so we removed some of the excessive bass traps in the corners. I had diffusers on the back wall that were giving too much colour so out of the room they went and they got replaced by absorbers. The ceiling cloud was also adjusted. The monitors were repositioned in the room and the music started to sound the way it was supposed to. The next problem was the oversized desk that was generating bad reflections so we moved it out of the way, now we were on the right track. Ruairi fine tuned the positioning and eq of the monitors and did some measurements that confirmed we were close and indeed done with phase one. It was great to see how every piece was affecting the listening environment , many thanks again to Ruairi  for sharing his knowledge and showing me how to identify and correct the problems by ear

 

[buildafriend]

Just a small disclaimer to help you avoid something I went through - I once tried to do some testing with some free software and it did a frequency sweet with my yamaha ns monitors from low to high while I had a mic set up to test room response. The frequency went up until past 18k where I lost most of my ability to hear it. Im not sure how high it actually went but saw a puff of smoke from each hf driver. That was the end of my hf drivers.

Good luck!
-JP

 

[Andy Peters]

I once tried to do some testing with some free software and saw a puff of smoke from each hf driver. That was the end of my hf drivers.

So that free software wasn't free after all!

 

[Whoops]

I honestly recommend using Room EQ Wizard Software
It's Amazing and Free!

http://www.roomeqwizard.com/

Features

    Frequency response measured using logarithmically swept sine signals for fast, accurate room acoustics and audio analysis measurements using an SPL meter, USB measurement microphone or analog measurement microphone
    Real Time Analyser with up to 1/48th octave resolution
    Spectral decay plots, waterfalls and spectrograms
    Impulse response, step response and energy-time curves
    Reverberation times derived in accordance with ISO 3382 in octave or one-third octave bands with results for Early Decay time (EDT), T20, T30 and an optimal fit RT60 figure, impulse response can be displayed with octave or one-third octave filter applied
    Harmonic and intermodulation distortion measurement
    Signal Generator offering sine waves, square waves, dual tone signals, CEA-2010 tone bursts, linear and logarithmic sine sweeps, random pink noise (full range, speaker calibration, sub calibration and custom filtered) and periodic pink and white noise
    Sound level meter with full integrating functionality including equivalent sound level and sound exposure level; mic/meter and soundcard calibration corrections applied; A, C or Z weighting
    Phase & Group Delay (measured, minimum and excess)
    Phase wrap/unwrap, minimum phase generation
    Impedance measurement and Thiele-Small parameter calculation
    Impulse Response delay calculation and adjustment
    Measurement arithmetic functions, add/subtract/multiply/divide/merge measurement
    Automatic identification of peaks in the response, automatic assignment of EQ filters to peaks and optimisation of filter parameters to counter the peaks and track a desired target response
    Waterfalls of predicted results of EQ can be viewed in the EQ panel and can update live as filter settings are adjusted
    Support for the Behringer DSP1124P, FBQ2496 and DCX2496, QSC DSP-30, Crown USM 810, MiniDSP, ADA, Emotiva UMC-200 and XMC-1, waveFLEX DSP A8 and Xilica XP2040 equalisers
    Room resonance analysis to determine the frequencies and decay times of modal resonances with pole-zero plots of the response and any filters applied
    "Modal" filter setting provided for parametric EQ filters to aid in correcting modal decay
    Room Simulator
    Frequency response import from and export to text files
    Impulse response import from WAV or AIFF files
    Export impulse responses of measurement or filter settings to WAV files with 16, 24 or 32-bit resolution
    Compensation for C-weighting when using an external SPL meter as the input, calibration files can be loaded for soundcard, microphone or SPL meter
    ASIO support
    Comprehensive help files within the application and on-line