Here´s my graphs. Comments please :-)

[Mastergod]

Hi again :-)

What I haven´t done yet, is to lower/heighten the monitors, move the monitors, change the listening position etc.

Maybe I could gain something by trying different things.

/Henning

[Jolida]

Originally Posted by Mastergod

Here I managed to get the pics as thumbnails :-)

Which software is this?

[Mastergod]

Fuzzmeasure for Mac.

[Mastergod]

So, now I have bass trapped more or less the whole room. This means wall - wall, wall - ceiling and floor - wall.


There are 1 to 2 feet left not bass trapped for each corner except from wall to wall which is trapped all the way. Maybe I can push in more traps, but I have now where it becomes very unpractical to add to the space that is left.

But, the decay in the low end is now even shorter but not perfect I guess.

When I looked at the graphs in the beginning of this post, the mid and the highs pretty much looks the same (at least to me :-). I have experienced with different numbers of panels on the side walls and the back wall, but without any major changes as I see it.

So here you can se what it looks like now......the name of the pictures tell if it is the left, right ot both speakers..

[Yosem]

Mastergod, i think you have something wrong in the high frecuencies. IMO This oscilation is not normal. Do you tested your speaker in the outside or something similar to a free field??. If you have a pc I recommend to measure with rew to compare the results.
In the low frecuencies you can make a helmholtz bass trap to fix the modal problem at 36hz

[Mastergod]

Hi Yosem.

I don't really know what you mean by "freefield".

What doesn't look right about the hi-end?

Yes, I can also do a test using REW on a PC. I will try that tomorrow.

/Henning.

[Yosem]

Freefield, outside of your room, maybe in front of your house or in your garden . I see a oscilation in your graphs that are not normal, maybe your microphone or your audio card are not correctly calibrated, the speaker usually are practically flat in that fecuencies

[jim1961]

Originally Posted by Mastergod

Hi Yosem.

I don't really know what you mean by "freefield".

What doesn't look right about the hi-end?

Yes, I can also do a test using REW on a PC. I will try that tomorrow.

/Henning.

I think he is talking about that "wavy" nature you and I discussed earlier, and I agree with him. It shouldn't look like that.

[Mastergod]

Thank you for your replies!

I will try to measure with REW tomorrow and see if that changes anything.

I am not sure I can measure outside these days due to heavy rain :-)

If I understand you right, this frequency area uaually are flatter than my graphs show, so I guess reality isn't worse at least :-)

/Henning

[jim1961]

Mine is not perfect either, but this kind of smoothness you should have.

This is @ 1/24th octave smoothing just like yours.

[Jens Eklund]

Originally Posted by jim1961

I think he is talking about that "wavy" nature you and I discussed earlier, and I agree with him. It shouldn't look like that.

That kind of response (including the comb filtering artefacts) are typical for measurements where you have problems with early, strong reflections (from the desk etc.). These problems are easily spotted by analysing the ETC. Another common cause for this, is if you by accident recorded the IR with both speakers playing. Unless the mic is carefully centred exactly in-between the speakers, the comb filter is what you get due to a slight delay between the two signals.

A general comment regarding scales and useful plots can be found here:Before posting your measurement results

[Mastergod]

Hi Jens.

Thank you for your reply!

The graphs have the same artifacts if I measure the left, right or both speakers.

For microphone placement, It is the same distance from it to both speakers. But I am not shure they are 100% alligned the same way.

If the ETC shows the early reflections are coming from the desk, how do I approach to solve it?

The desk is there :-)

/Henning

[Jens Eklund]

Monitor (LCD) vs speaker placement

Monitor & Mixing Desk Placement - Reflection Issues

[Mastergod]

Thanks!

[Mastergod]

Hi again.

Here is the ETC for the left and rigth speaker. Is the sinner the desk :-)

/Henning

[jim1961]

Originally Posted by Mastergod

Hi again.

Here is the ETC for the left and rigth speaker. Is the sinner the desk :-)

/Henning

Your settings need tweaking.

1) we need to see to 0 db on the vertical plot
2) the signal should start at 0 time, not 30 something ms

Here is an illustration:

[Mastergod]

Hi again.

I can now confirm it is the desk causing the issue. I put a panel on it and the artifact was gone.

I will post the graphs tomorrow.

Now, how to solve it would be next step :-)

[Mastergod]

Here's a picture...

[Mastergod]

Just for info.

Here you see the front, side and back wall. On the front front wall picture you also see the ECM8000 microphone. The "whole" room is bass trapped.

Here is the studio building thread:
Building a studio in our rehersal space - low budget.

/Henning

[AwwDeOhh]

can you angle your desk? try propping up the back legs for now and see if that helps

[Mastergod]

Thank you for your advice. I will try to do that!

/Henning

[Jens Eklund]

How about reducing the size of that big reflector?

Tilting it might also help, as would increasing the distance to the monitors.

[DaVogi]

your highs seemed overdamped and the lows not enough... this is typical if you use as much broadband absorption than you did. not every absorber has to work in the whole frequency domain. your superchunks in the front for example....

[Jens Eklund]

Originally Posted by DaVogi

... this is typical if you use as much broadband absorption ...

+1

Sticky with links?

[Glenn Kuras]

Originally Posted by DaVogi

your highs seemed overdamped and the lows not enough... this is typical if you use as much broadband absorption than you did. not every absorber has to work in the whole frequency domain. your superchunks in the front for example....

You could use FRK on the fronts or better yet a slat design to help scatter/a bit of diffusion.

[Mastergod]

Here is the newest measurement with panels lying on the desk.

/Henning

[Mastergod]

Thank you for your answers! It is very much appreciated!

Originally Posted by Jens Eklund

How about reducing the size of that big reflector?

Tilting it might also help, as would increasing the distance to the monitors.

Hi Jens. Which absorber are you reffering to?

Originally Posted by DaVogi

your highs seemed overdamped and the lows not enough... this is typical if you use as much broadband absorption than you did. not every absorber has to work in the whole frequency domain. your superchunks in the front for example....

How do I read my measurements to see that the highs are overdamped. If I change the absorbtion to something "thinner" how would it show in the
graphs?

When you say the lows are not damped enough, are you refering to the decay? I have attached the latest Waterfall.

Originally Posted by Glenn Kuras

You could use FRK on the fronts or better yet a slat design to help scatter/a bit of diffusion.

Glenn: Do you mean to "slat" the absorbtion panels?

[Glenn Kuras]

Originally Posted by Mastergod

Thank you for your answers! It is very much appreciated!



Hi Jens. Which absorber are you reffering to?



How do I read my measurements to see that the highs are overdamped. If I change the absorbtion to something "thinner" how would it show in the
graphs?

When you say the lows are not damped enough, are you refering to the decay? I have attached the latest Waterfall.



Glenn: Do you mean to "slat" the absorbtion panels?

Yes it would be slats in front of the absorptive material. Run them vertically if you can.

[DaVogi]

Originally Posted by Mastergod

How do I read my measurements to see that the highs are overdamped. If I change the absorbtion to something "thinner" how would it show in the
graphs?

When you say the lows are not damped enough, are you refering to the decay? I have attached the latest Waterfall.

you can see that in the waterfall (full bandwith and 50-60dB range) or rt60 (yes it isn't a real rt60 but still informal) graphs, but it is hard to see in your chosen scaling.

you don't want to make your traps thinner (that would even WORSEN your low/high absorption ratio) but you want traps that only should absorb low mids and bass like your superchunks in the front to REFLECT highs. slats can do that as glenn already mentioned.

[Jens Eklund]

Originally Posted by Mastergod

Hi Jens. Which absorber are you reffering to?

By "big reflector", I´m referring to your desk


EDIT:
Add wood slats to face of bass trap to retain some reflectivity?
Will this rockwool work for me?
Velocity based vs. pressure based absorbers