Why you need room EQ even with the speaker with perfect anechoic measurements

[Krunok]

Ok, I will not say Revel performa3 F208 is a speaker with "perfect" anechoic measuements but most of us would probably agree that it measures really well.

Here it is shown how well:

I would say that if it wasn't for a little fluctuation in DI's around XO point at 2.2kHz it can really be called perfect.

Few months ago I had a chance to listen to it in a local dealer's demo room. Room was app 25m2 in size and was treated professionally but not to much to keep resemblance with typical listener room. Here is how RT60 looks:

And here is how frequency response looks, 3m from the speaker, on-axis, 1/12 smoothing:

And that is exactly how it sounded: everything was pretty much perfect except for very uneven bass that continuously kee swinging betweeen exaggerated boomy notes and silent ones. So make no mistake, room EQ is a necessity for every speaker if you want to have a good sound in your room.

 

[pma]

You are showing room modes at microphone specific placement, in LF. Not a speaker response. Move microphone 50cm forward/left/right and you will get different curves.

 

[Krunok]

You are showing room modes at microphone specific placement, in LF. Not a speaker response. Move microphone 50cm forward/left/right and you will get different curves.

This is RTA average response made with moving microphone method on an aera that covered 2 seats sofa.

 

[pma]

However still room modes, obtained by averaging of several measurements.

 

[Krunok]

However still room modes, obtained by averaging of several measurements.

Room modes are the ones that affect what you hear, so what exactly is your point?

Primary purpose of room EQ is to compensate for non-linearities coming from room modes, SBIR effects etc, not to correct speaker's response. With a measurement like this one you start room EQ process.

 

[Blumlein 88]

However still room modes, obtained by averaging of several measurements.

But you'll hear those room modes as they measure more or less.

Krunok beat me to it.

 

[Krunok]

But you'll hear those room modes as they measure more or less.

Krunok beat me to it.

Exactly. He should stick with amps and do some more reading about room EQ before posting.

 

[Krunok]

This is response of the same speaker taken at app 50cm, on axis, log sweep. This measurements much more resembles anechoic speaker response than previous one but it is not what you would hear sitting at LP.

 

[pma]

Room modes are the ones that affect what you hear, so what exactly is your point?

Primary purpose of room EQ is to compensate for non-linearities coming from room modes, SBIR effects etc, not to correct speaker's response. With a measurement like this one you start room EQ process.

But you'll hear those room modes as they measure more or less.

Krunok beat me to it.

That's correct, but the thread question
Why do you need room EQ even with the speaker with perfect anechioc measurements
is pointless because room modes are independent of speaker used.

 

[Krunok]

That's correct, but the thread question
Why do you need room EQ even with the speaker with perfect anechioc measurements
is pointless because room modes are independent of speaker used.

It is by no means pointless because with room EQ you are correcting room modes, SBIR effects etc. Sure, room modes, SBIR and other room/position related artifacts are independent of speaker but once you put your speaker in your particular room they both form a new unique acoustic system and that one needs EQ correction to sound well at your LP.

 

[Krunok]

Please read this again as this is the answer to the thead question:

Once you put your speaker in your particular room they both form a new unique acoustic system and that one needs EQ correction to sound well at your LP.

And this is the truth no matter how perfect spinorama of your speaker looks like. Every speaker needs room EQ the very moment you put it into the room and start listening to it.

 

[pma]

Yes, but it will always work only to some degree. Maybe change position of speakers and listening place? You have shown it is possible.

 

[Krunok]

Yes, but it will always work only to some degree. Maybe change position of speakers and listening place? You have shown it is possible.

Sure, room EQ will optimise response only for the area you measured. If you change position of the speakers or make any major changes to the room like replacing furniture, add some 3" rug or stuff like that, acoustic pciture will change and you will have to do room EQ again.

If you are asking if you can change listening position and/or re-position your speakers instead of doing room EQ, typically the answer is no.

And no, my measurement taken from 50cm from F208 doesn't prove it is possible as you defintiely won't get a good sound listening F208s from 50cm distance as they were not designed to be near-field monitors but speakers for mid to larger rooms.

 

[Krunok]

In my music room the speakers have been positioned for best sound and I certainly do not prefer the sound with "room correction" applied by my DSPeaker Anti-mode Dual core.

Do you have measurements of your setup wihtout room EQ?

Btw, your DSP must have done something wrong as properly done room EQ doesn't have any specific "sound" - it simply makes FR linear which sounds as it should.

 

[Soniclife]

This is RTA average response made with moving microphone method on an aera that covered 2 seats sofa.

Do you have link to that procedure, I keep meaning to try it out.

 

[Krunok]

Do you have link to that procedure, I keep meaning to try it out.

Sure, it is well explained and demonstrated here.

 

[vavan]

This is response of the same speaker taken at app 50cm, on axis

looks quite similar to mine taken at ~1m

 

[Blumlein 88]

Another way to accomplish that, though I don't know how different the results would be, is to make a few measurements over the area of interest. Pull all of them up in the All SPL page. Lower left corner is a button for averaging the measurements. Hit that and display only the average. You can then save that average for use later. I've done that for different sized areas. I often do that based upon the head position for the main LP. I do a 3 by 3 grid with 1 foot spacing. So you get 9 measures, center, left and right at the head position, the same 1 foot forward, and again 1 foot to the rear. Average the result. I got this idea from how Dirac suggests you calibrate their software.

Here is one I expanded over a larger area using 12 measurements. The bright yellow line is the average of them. This is from an LSR305 mk I.

 

[Krunok]

I know this is a popular view here but I do not agree.
Firstly I know one "hears through" a room and secondly the idea that a test signal could accurately measure the time dependant effect of exciting resonant modes (room modes) is actually laughable if you have done any work on noise and vibration (I am an old bloke but this used to be my job).
Certainly you can get a before and after plot of the microphone output for the excitation type you used for the measurement, at the place(s) you measured. Mine shows the bass peaks lopped off. That means it doesn't sound right for the room any more (to me).
I have been recording with microphones for 50 years and reducing resonance excitation by moving speakers for almost as long. I am happy with the results and absolutely do not agree with your point of view though accept you and many others here are of like mind.


Anybody who has done any recording knows that what you hear at a particular location and what the output of a microphone at the same location sounds like are quite different. You automatically compensate for room, luckily, if you didn't life would be very confusing as you moved about, even in the same room never mind from place to place.
Try it. You probably won't be quite so confident afterwards in the technique if your experience is like mine.

It has been shown by Toole and others that 10dB sloped down smooth target response curve generally sounded best to most of the folks. As response curve needs to be smooth you can't really say the peaks have been loppedd off as the peaks weren't suppose to be there at first place.

P.S. You are saying you "have been recording with microphones for 50 years" but you still didn't show measurements of your system. Heh..

 

[Purité Audio]

I would advise just to adjust minimum phase bass peaks, below a couple of hundred hertz.
Keith