Calibrating the Monitors and the room - Pink Noise Octaves?

[scrnplyr]

I finally got around to doing some much needed calibration of the speakers (83 db is louder than I remember) and decided to calibrate the room using the same PT10 noise generator plug in.

The idea was to generate pink noise at 1/3 octaves at the following frequencies: 31 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz. The only problem is that the Octave slider on the noise generator is grayed out - kaput - when pink noise is selected.

If I switch the generator to sine, square, sawtooth, or triangle the frequency slider becomes active, for white noise and pink noise it becomes inactive.

I've been told pink is the way to go, so do I have any options here or do I trust my 4 walls are perfectly aligned with the audio universe?

:confused:

[Craig F]

pink (and white) noise is broad band noises yo can not adjust the frequency of it becuse it is all frequencies
what are you trying to calibrate? SLP or are you tuning your room with an equalizer?
for SPL set the generator to pink, in the next slot put EQ3 7 band with the HPF at 500 and the LPF at 2000 on there steepest slopes, this is band limited pink it helps take room modes out of play for setting playback level
if you are EQing the room you need a RTA to see where you need to massage the response of the room per speaker and what you target curve is (flat, film X, TV)
it's easier to EQ the room first and use an arbitrary level point that the room is close to say 90 on the RTA then come back and set the room's level to what you want it to be with an SPL meter

[albee1952]

My 2 cents relates to sound accuracy, not volume. Pink noise is great, if(and only if) you have an accurate analyzer of some sort. I happen to use SMAART Live with a measurement mic. It covers the typical RTA function, but on steroids, and allows for accurate phase and time delay adjustment(my subwoofer is fed from a digital crossover with custom filters to create an asymmetrical slope and to time align the sub to my main speakers). Without that level of measurement, my next recommendation takes a little time and some good old "analog" help(namely a pencil and paper:D). With this, you sit in your normal mix chair and use the sine wave. Start at 500Hz(really, anywhere is fine, but you need to start with a volume that is loud enough, but too loud(around 85db). Slowly(very slowly) sweep up and take notes on any frequency that sounds either louder or softer(with luck, it should be fairly smooth going up from 500Hz). Inaccuracies in the upper range could be due to reflections off the walls, ceiling, desk top.

Sweeping down is likely to reveal some serious imbalances which will likely start just below 200Hz. Be patient and take lots of notes on lots of frequencies. Use your ears(and, if you have a flat mic, use that to help support what your ears tell you). In the average room(let's say, a spare bedroom with most any 8" monitor) I would expect to find at least 2 frequencies that are way down(like 12 to 14db softer) than the average volume. You may also find a couple that are way hotter. These are likely due to room dimensions. To get help here, you need bass trapping and/or to move your setup. IIRC, the ideal listening position is 38% away from the front wall(adjust according to the front-to-rear dimension). In my room, I had no option and sit almost dead center(the worst spot:o:o). This left 1 big hole at 50Hz. My solution is to dial the subwoofer so that it fills in the hole, right at my mix chair(I turn the sub off if I have a producer on the couch as the sound is flat on the couch WITHOUT the sub(a reasonable tradeoff ). Be methodical and do more research as needed. Good luck:D

[Emcha_audio]

Rew 5 is not bad either.

[scrnplyr]

Wow! Great info guys. I've put off dialing in the room for months because I'm a 2 bit lazy audio engineer. I also moved from a nearly perfect small EQ tuned room to a much bigger cave like untuned room.
I knew it was time to analyze the new room when a 4 inch change in my head/ear position caused the bottom to drop out precipitously from the mix for no other reason.
I should have remembered that white N pink both have all freqs - we used to do live sound w/ a white noise analyzer and one cheap 32 band graphic eq to flatten the room.

Those were the days when "digital" meant "wristwatch"

Thanks again

[Emcha_audio]

Wow! Great info guys. I've put off dialing in the room for months because I'm a 2 bit lazy audio engineer. I also moved from a nearly perfect small EQ tuned room to a much bigger cave like untuned room.
I knew it was time to analyze the new room when a 4 inch change in my head/ear position caused the bottom to drop out precipitously from the mix for no other reason.
I should have remembered that white N pink both have all freqs - we used to do live sound w/ a white noise analyzer and one cheap 32 band graphic eq to flatten the room.

Those were the days when "digital" meant "wristwatch"

Thanks again

You'll want to use a pink noise as it has a fixed equal power throughout the frequencies. Also, as it was probably mentioned already, if your room is not treated, tuning the room will not change the standing waves. The only way to correct those is to modify the geometry of your room not to mention that size will also have an impact on that. Then use bass traps, broad frequency absorbers, diffusers to control the frequencies and flutter echoes. At that point, if you're still not satisfied you can always fine tune the room with using pink noise and a frequency analysis program, like rew 5 and others. Using the new Geq from waves might be advantageous in this, as the modern mode offers true plateau control that is not additive and is not using proportional Q filters. Just add it as the last plugin of your master but don't forget to take it out when you bounce your file. But trying to eq your room without even doing the other steps first will be a waste of time.

[JFreak]

The brand new Waves GEQ plugin is a godsend for this. Just grab a nice and very flat RTA mic and you have all you need :D

[Bill Denton]

IIRC, the ideal listening position is 38% away from the front wall ...

I recently read an article, and I believe it may have been from the guy who put out the 38% in the first place, that said the 38% is really only a guide for a starting point for small rooms, and that the actual "best" position could vary considerably from that percentage.

You can probably do a Google search and find the article...I think that's how I found it in the first place...

[albee1952]

More good info from others here. Just remember a few details. 1-If you EQ your setup with a plugin, you need to remember to remove that plugin before you bounce. 2-Don't EQ your system with an analog third-octave EQ because it will induce all sorts of phase shift(just the way those things work) and do as much damage as it does help. 3-Octaves is not enough resolution(1/3rd octave is borderline). 4-the most important thing you can do here is "learn" what the room/speakers sound like. Knowledge is power:D(what you choose to do after you KNOW what's going on, is less important than just knowing):o

[scrnplyr]

pink (and white) noise is broad band noises yo can not adjust the frequency of it becuse it is all frequencies
what are you trying to calibrate? SLP or are you tuning your room with an equalizer?
for SPL set the generator to pink, in the next slot put EQ3 7 band with the HPF at 500 and the LPF at 2000 on there steepest slopes, this is band limited pink it helps take room modes out of play for setting playback level
if you are EQing the room you need a RTA to see where you need to massage the response of the room per speaker and what you target curve is (flat, film X, TV)
it's easier to EQ the room first and use an arbitrary level point that the room is close to say 90 on the RTA then come back and set the room's level to what you want it to be with an SPL meter

Craig,

my goal was to tweak the bigger room for frequencies that seemed out of place. In the smaller room, we were able to create a relatively flat freq range after doing some simple room treatment and analyzing the room with a graphic equalizer and white noise. I'd done this many times in running live sound in various clubs with good results.

I have GEQ to get me started. Thanks for the step by step.

I also like Albee's method which forces me to use my ears and brain at the same time - not necessarily an easy task - but I like a good adventure.

Trying to calibrate all the variables in the room has become somewhat of an obsession lately because of how different the sound in the room is compared to other speakers I've been playing the rough mixes on.

I've also spent some quality OCD time moving the monitors to and fro/left and right trying to find the sweet spot in relation to my chair. For my set up the monitors sound right at roughly 6' back with approx 10' between them. Depending on how I angle them I can increase the SPL by approx 3db.

Anyone who's ever run live sound knows exactly where the low frequencies break in a room and while I can't complain too much, I do find myself leaning back slightly to find the kick drum/bass guitar in the mix - which usually appears dramatically at about 4 inches back from my natural sitting position.

While playing back an adjusted mix, my head can be seen swaying back and forth like an overstimulated chicken strutting to the sounds of rock and or roll - a small price to pay to hear the kick drum congeal with the bass.

[Emcha_audio]

If you`re using a sub, that means that your cross over is not set properly and that your lower frequency timing is off compared to the rest.

[scrnplyr]

Manny

I'm not using a sub, just a pair of Yamaha MSP5's that have held up pretty well for the past 13 years - decent high freqs, decent mids, and so-so lows up close - very good lows from a certain distance approx 5 feet. I need new monitors, but I don't think that's the main issue. I'm guessing it has more to do with the room acoustics (or lack thereof). I've internalized and compensated for the lack of lows during mixing and I seem to have a handle on it. Annoying yes, but not a deal breaker.

[Emcha_audio]

Ah, alright there. In that case once you treat your room this should hopefully be solved for you.