EQing a room with swept sine vs pink noise

[ggegan]

Every rerecording stage I have ever worked on has used pink noise to EQ the B chain. The Dolby techs always use pink, and to the best of my knowlege, so do the in-house engineers at all the major studios. For my personal 5.1 mix room, I have always used pink as well, however, today I did an experiment and tuned it using FuzzMeasure with a 5000msec full frequency swept sine impulse. I have to say that it was a lot easier and I wound up using considerably less EQ to get the curve I wanted. However, I'm not sure if doing it this way will result in an accurate room curve.

Is there any reason not to switch to this method rather than staying with the pink noise approach? Why do the major studios use pink rather than swept sine?

I still have my EQ settings from using pink saved in a BSS Soundweb file, so I can always go back to the previous EQ if that is preferred.

[Ethan Winer]

Pink noise is fine for large rooms and large venues. For a home-sized room you really do need to use sine waves. Not manually swept, but with software like Room EQ Wizard. Then you'll also see the ringing decay times. More here:

Room Measuring Primer

--Ethan

________________
The Acoustic Treatment Experts

[DanDan]

The Pink, RTA, third octave thing is an established standard. Even at live gigs now the more modern methods are becoming common. Smaart is popular.
Swept Sines, MLSS, etc. measurment is a relatively recent thing. Probably only possible due to the extremely high powered computers which are common now.
Fuzz and REW will work at 1/3 octave if you want them to.
Note the correcting eq is most likely valid for the measuring mic position only. Try moving the mic to where each ear will be. Even that gap will cause quite different readings. Average them to get an idea of how your head/ears will hear. Stay away from the mic when measuring. Do single speaker measurement for full range Freq Resp and ETC. Also try driving both when investigating the LF and modal response.
http://www.gearslutz.com/board/studi...er-v2-1-a.html
DD

[Tom Higgins]

From what I've read, you shouldn't be using EQ to fix room acoustics?

[ggegan]

Originally Posted by Tom Higgins

From what I've read, you shouldn't be using EQ to fix room acoustics?

If you read the comments carefully, you will note that most acoustics experts don't say not to use EQ, they say to first focus on speaker and listening position, then on acoustic treatment, and when you have done as much as you can using those methods, then touch things up with EQ, if needed (and use it correctly, of course).

Besides, the only way I know of to conform to an industry standard curve like the X curve or modified X curve is to use EQ.

[Tom Higgins]

Fair enough.

But you didn't mention if you had actually placed your monitors properly nor if you had any acoustic treatment.

[ggegan]

Originally Posted by Tom Higgins

Fair enough.

But you didn't mention if you had actually placed your monitors properly nor if you had any acoustic treatment.

I have done due diligence in terms of speaker placement and acoustic treatment for the current room where I am mixing. It just needs a few tweeks and to have a modified X curve applied to the B chain.

[Tom Higgins]

I don't know anything about x-curves (post-production stuff?) so what I say may be rendered redundant by that fact.

However, I was reading another article by Mr Winer (Acoustic Treatment and Design for Recording Studios and Listening Rooms) and it does stress that EQing a room has led to worse results. Scroll down to Sidebar: Fine tuning the control room.

I'm not trying to be deliberately annoying, I just want to help (and see if I should do it as well )

Thanks, Tom

[ggegan]

Originally Posted by Tom Higgins

I don't know anything about x-curves (post-production stuff?) so what I say may be rendered redundant by that fact.

However, I was reading another article by Mr Winer (Acoustic Treatment and Design for Recording Studios and Listening Rooms) and it does stress that EQing a room has led to worse results. Scroll down to Sidebar: Fine tuning the control room.

I'm not trying to be deliberately annoying, I just want to help (and see if I should do it as well )

Thanks, Tom

Probably Ethan should chime in on this, but I think he may be referring to improper use of EQ, such as attempting to deal with nulls by applying extreme frequency boosts, or not recognizing when an apparent nonlinearity viewed at 1/3 octave is not what it seems because it is actually the result of averaging numerous comb filtering peaks and dips that are evident at higher resolution. What I'm doing is pulling down a few frequency ranges using parametric EQ bands with pretty low Q, mostly an octave or more in width.

The X curve is a film industry audio standard for large rooms where the high end is tapered down 3dB per octave starting at 2kHz and the low end is tapered down 3dB per octave starting at 50Hz, with a high pass around 30Hz. Because my room is small, I use the modified X curve, which tapers at 1.5 dB per octave.

[DanDan]

Tom, the rules of thumb are falling like bowling pins.
It is perfectly viable to Eq the speakers to achieve a particular target response in the room, e.g. X curve, or the Bruel and Kjaer listening curve. (+3dB around 100Hz tilting to -3dB around 10K.)
Also, there are some speaker/room interactions which are amenable to Eq.
e.g. Proper Soffit mounting leads to a bass boost which can be completely corrected by a simple LF filter.
But there are more. Anyone interested, I recommend the Minimum Phase section in the REW manual.
Room Eq Wizard, get it?
DD

[Tom Higgins]

I stand corrected