Preferable Frequency Response!!

[davea]

Hi All,

Here are three pics from my room. A is the mic postioned at 38% and monitors placed in an equilateral triangle. B is just the mic placed a foot back and C both the mic and monitors placed a foot back. I was wondering what your thoughts were on the best position based on these pics. Thanks !!

[Ghostwheel]

Originally Posted by davea

Hi All,

Here are three pics from my room. A is the mic postioned at 38% and monitors placed in an equilateral triangle. B is just the mic placed a foot back and C both the mic and monitors placed a foot back. I was wondering what your thoughts were on the best position based on these pics. Thanks !!

Man, I thought my room has issues, but looking at this, I am almost relieved. Sorry to say this dude, but this is some really wacky frequency curve you got going on there. What are the dimensions of the room and do you have any acoustic treatment going on (my guess is no)? Are you using a linear response mic?

[davea]

Funnily enough, I have about ten traps and a cloud. The dimensions are 21 feet long by 9 feet wide by 8 feet high. And I have a calibrated mike. Is it that bad ?? i always thought that if you got your reponse between +- 6db you were doing ok?

[Ghostwheel]

Originally Posted by davea

Funnily enough, I have about ten traps and a cloud. The dimensions are 21 feet long by 9 feet wide by 8 feet high. And I have a calibrated mike. Is it that bad ?? i always thought that if you got your reponse between +- 6db you were doing ok?

It's REALLY bad below 100Hz. Otherwise it's OK. I bet you are not hearing a lot of bass with this setup...

[Ghostwheel]

Originally Posted by davea

Funnily enough, I have about ten traps and a cloud. The dimensions are 21 feet long by 9 feet wide by 8 feet high. And I have a calibrated mike. Is it that bad ?? i always thought that if you got your reponse between +- 6db you were doing ok?

And C is the best of the bunch, I believe. If you can get rid of that nasty 60Hz dip, then you will actually have a pretty decent curve, although I am not sure about the peak at 10KHz (may be able to tame that with EQ although that's generally not a very popular idea; perhaps if your monitors have a treble control, you can decrease the highs a bit).

[davea]

thanks for your input !!!

[davea]

That 60hz dip seems to be prominent in all three pics. Dont know what to do to get rid of it!!

[Glenn Kuras]

I would have to go with C also. Do you have panels between you and the monitors on the right and left wall in the early reflection points? Trust me I have seen rooms much worse then this.
Are you facing the long wall or the short wall? You should be facing the short wall.

Glenn

[avare]

To answer your question first, A and B are you moving your head. So the question becomes B and C. Between those two C is better.

There is severe comb filtering going on. Do you have the first reflection points covered?
What is the location of the console relative to the mic and monitors?

The 60 Hertz dip could be related to height or width of the room. Is there a dimension around 9' that the mic is centred on?

Andre

[davea]

Hi glen yes I am facing the short wall. Andre the width of the wall is 9ft which I guess is what is causing th 60hz dip.

Also the stands tend to ring quite badly when doing a sweep. Once I find the correct position I am going to fill them with sand to dampen this effect.

[nosebleedaudio]

Originally Posted by davea

Hi glen yes I am facing the short wall. Andre the width of the wall is 9ft which I guess is what is causing th 60hz dip.

Also the stands tend to ring quite badly when doing a sweep. Once I find the correct position I am going to fill them with sand to dampen this effect.

Do you have the speakers decoupled from the stands?
Sorbothane is very good...and yes heavy stands are very important.
What percentage of walls and ceiling are treated?
8 foot and 9 foot are also very close to each other, something you can't correct, so more bass trapping...
Also make sure your dimensions between speakers and boundaries are not the same, at least a foot different.

[davea]

Hi Mike, Yeah the speakers are decoupled. I Know what you mean when you say that two of the dimensions are quite similar.

I guess more trapping it is. Will more trapping reduce that 60hz null ?? I find that moving the speakers and mike around just shifts the problem to a different node.

[nosebleedaudio]

Originally Posted by davea

Hi Mike, Yeah the speakers are decoupled. I Know what you mean when you say that two of the dimensions are quite similar.

I guess more trapping it is. Will more trapping reduce that 60hz null ?? I find that moving the speakers and mike around just shifts the problem to a different node.

Trapping will help, finding the best location may not be obvious.
Check out Bob Hodus site. http://www.bobhodas.com/pub4.html
You will find that very interesting...

[avare]

Originally Posted by davea

Hi Mike, Yeah the speakers are decoupled. I Know what you mean when you say that two of the dimensions are quite similar.

I guess more trapping it is. Will more trapping reduce that 60hz null ?? I find that moving the speakers and mike around just shifts the problem to a different node.

If you are in the middle of two walls, you ALWAYS be in a null for the lowest mode. Don't worry too much about though. If you don't the sound of null, just move you head 6". These modes are what make a room sound like, well, a room.

You forgot to respond to two of my questions:

Do you have the first reflection points covered? and
What is the location of the console relative to the mic and monitors?


Andre

[Glenn Kuras]

Originally Posted by davea

I guess more trapping it is. Will more trapping reduce that 60hz null ?? I find that moving the speakers and mike around just shifts the problem to a different node.

Yes more bass trapping will always help but look at the other things people are telling you first and go from there.

Glenn

[davea]

Mike, thanks for that link!! Will read it now.

Andre thanks for your time too and Glen,

1) Yes got the first reflection points covered.

2) Sitting in the mix position and placing a mirror on the table I can just about see the tweeters of the Adam. Is this what you mean? To remedy this I am thinking of sawing the table in half which would eliminate this problem.

I can send you a picture of my test setup as is if you want ?

Thanks again chaps !!

[nosebleedaudio]

One more thing that can make a difference, is the console or stand its on, is it open on the bottom? This allows the low end to move more freely in the room.

[davea]

Hi Mike, Speakers are on a stand behind the console. For now the bottom of the console is open as I have to move it about to get the best spot. Once I have which I think I have now, I will saw the desk in half (so that tweeter reflection is eliminated), fill the speaker stands with sand and the racks up underneath with equipment.

[davea]

here is the test setup

[Ethan Winer]

I see plenty of room for more traps in the wall-ceiling corners, and even on the floor in front of your feet. That's a great place for bass traps because there's nothing to install. Just lay them sideways on the floor, tipped back against the front wall. Ten more traps in that room will make a big improvement.

--Ethan

[SRS]

I wouldn't saw that desk in half. Just place some folded towels (vary the thickness to suit) on it at the first reflection points when critically monitoring.

[davea]

Hi Ethan. Did not even think about that. Cheers !!!!

[davea]

Originally Posted by SRS

I wouldn't saw that desk in half. Just place some folded towels (vary the thickness to suit) on it at the first reflection points when critically monitoring.

Hi Srs. If I could chop the desk in half, would that be better or just placing 2" of rock wool on the desk wrapped in material across the first reflection zone do the same thing for reflections from the tweeter ?

[nosebleedaudio]

Can't really tell what's on the ceiling...
How far back are your monitors from the desk top?
What is the difference between floor to wooker and ceiling to woofer?

[SRS]

Well, I am not an acoustician by any means, but I have done lots of research and experimentation over the years in my studios. Just wanted to get that out there. In my opinion and experience, the first reflection points coming from the monitors is relatively focused on a small portion of either the desk/console, or the floor (if the desk is not there). In the picture I see of your room, I would not try and eliminate the desk by going through the process of sawing it in half, but just by taming those first reflections off of it when in use. I would think that two inches of rock-wool might be a bit extreme for this purpose. I have tried various objects with much success to do the same thing. Such as a small hand towel on both points of each monitor, folded up on the desk, or a (gasp... piece of foam) there to serve the same purpose.

You just really need to kill the upper mid and high freqs bouncing off the desk. Anything but that hard flat surface will affect this reflection obviously. I just think that sawing your desk (precious real estate) away may be a bit extreme. Although in mastering facilities and critical listening rooms, there is often nothing but the equipment sitting on the floor (or in a minimal rack) and the sweet spot throne.

My 2 cents on the subject. Hope it helps grow some further thoughts...

[Glenn Kuras]

Originally Posted by davea

Hi Ethan. Did not even think about that. Cheers !!!!

Oh yea traps along the floor area is a pretty smart way to do it (if you have the room). If you ever have to move them to other room you can do so without having to unmount them.

Glenn

[davea]

Originally Posted by nosebleedaudio

Can't really tell what's on the ceiling...
How far back are your monitors from the desk top?
What is the difference between floor to wooker and ceiling to woofer?

The ceiling above is 4" of rock wool supported on a frame. The monitors are about two feet away from the console but would be three if I chopped the desk . Have to measure woofer to floor and ceiling but will do. Cheers

[davea]

Originally Posted by SRS

Well, I am not an acoustician by any means, but I have done lots of research and experimentation over the years in my studios. Just wanted to get that out there. In my opinion and experience, the first reflection points coming from the monitors is relatively focused on a small portion of either the desk/console, or the floor (if the desk is not there). In the picture I see of your room, I would not try and eliminate the desk by going through the process of sawing it in half, but just by taming those first reflections off of it when in use. I would think that two inches of rock-wool might be a bit extreme for this purpose. I have tried various objects with much success to do the same thing. Such as a small hand towel on both points of each monitor, folded up on the desk, or a (gasp... piece of foam) there to serve the same purpose.

You just really need to kill the upper mid and high freqs bouncing off the desk. Anything but that hard flat surface will affect this reflection obviously. I just think that sawing your desk (precious real estate) away may be a bit extreme. Although in mastering facilities and critical listening rooms, there is often nothing but the equipment sitting on the floor (or in a minimal rack) and the sweet spot throne.

My 2 cents on the subject. Hope it helps grow some further thoughts...

Thanks for your thoughts. I dont mind sawing the desk as it eliminates the reflections as well. I like your thoughts on having as little in the way as possible !!

[avare]

Great stuff! The picture helps a lot.

First Reflections

Looking at the picture, you definitively have the same side reflection points (like left speaker left wall to listening position) covered. However it almost looks like you do not have the opposite side (left speaker right wall to listening position) covered. Please clarify this.

The Desk

Before you cut up the desk, take it out of its position and repeat the measurements. This will show much negative reflections are coming from it.

Mic Height

Just to confirm, you tested with the mic at 42"?

Bass Trapping

From looking at your test results, bass trapping is not a high priority at this time. We wrote already about the null at the low end. The rest of the frequency range is the highest priority.

Keep the questions coming. The more you know, the better your space will be.

Andre

[Glenn Kuras]

The Desk

Before you cut up the desk, take it out of its position and repeat the measurements. This will show much negative reflections are coming from it.

Or just cover up the desk with some REALLY thick blankets. Might not be perfect, but better then moving the desk.

Glenn