Tool for identifying room treatment?

[nebunebu]

Thank you for all your replies. I got a fair understanding of what needs to be done to optimize my room and what areas one necessarily can't fix easily.
Now I have to use some time to come up with some ideas on how to make this room look like a regular room, but still have treatment.

Will post some updates in a few months

Regards
Nebu

 

[goat76]

Room measurements are: 6m (19.68inch) length x 4m (13.12inch) width x Ceiling height max 3.8m (12.4 inch).

Are you sure about those measurements?
When looking at the picture, it looks like the distance between the wall where the speakers are and the wall where the sofa is placed can't be much more than about 3 meters.

 

[Chris A]

In terms of waterwall on all of the measurements, I can't really say that acoustic treatment has had any effect on it?

If you look at the "overlays" tab, then choose "RT60" (i.e., reverberation time), I think you will see the combined effect of each room treatment, such as this:

RT30 is definitely better (i.e., between 0.2 to 0.5 seconds, and flatter vs. frequency). That's better. I'm sure that you can hear that.

What could be the cause of the major dip from 60 to 80 hz thats been showing on all measurements?

If you look at excess group delay, you will see the portions of the curve that are non-flat. These are areas of non-minimum-phase reflections (i.e., you can't EQ these disturbances). Look at the big negative-going spike at 70 Hz. That's a room mode (i.e., dependent only on the internal dimensions of the listening room):

As you can see there are also other frequencies (39, 83, 212, 322, 992, 1588, and 2190 Hz) where there are other group delay disturbances. Generally, anything below 200 to 250 Hz is room mode-related, while those frequencies above 250 Hz are usually related to loudspeaker-room or loudspeaker-microphone-room placement. Even higher frequency GD disturbances are usually due to loudspeaker performance irregularities.

Chris

 

[nebunebu]

Are you sure about those measurements?
When looking at the picture, it looks like the distance between the wall where the speakers are and the wall where the sofa is placed can't be much more than about 3 meters.

You have a keen eye when measuring i did the non scientific way which we learned in elementary school

 

[nebunebu]

If you look at the "overlays" tab, then choose "RT60" (i.e., reverberation time), I think you will see the combined effect of each room treatment, such as this:

View attachment 400754

RT30 is definitely better (i.e., between 0.2 to 0.5 seconds, and flatter vs. frequency). That's better. I'm sure that you can hear that.


If you look at excess group delay, you will see the portions of the curve that are non-flat. These are areas of non-minimum-phase reflections (i.e., you can't EQ these disturbances). Look at the big negative-going spike at 70 Hz. That's a room mode (i.e., dependent only on the internal dimensions of the listening room):

View attachment 400758

As you can see there are also other frequencies (39, 83, 212, 322, 992, 1588, and 2190 Hz) where there are other group delay disturbances. Generally, anything below 200 to 250 Hz is room mode-related, while those frequencies above 250 Hz are usually related to loudspeaker-room or loudspeaker-microphone-room placement. Even higher frequency GD disturbances are usually due to loudspeaker performance irregularities.

Chris

Woah! Thats a neat way of doing the interpretation. Did not know about that feature. I'm looking into building some acoustic treatment without making it look like a studio. Currently fiddling with this type of design concept (attached)

The idea is to use some kind of fabric for the "waves" and have an absorbent material in the back of that frame. Guessing i will build it 2 meter wide , 1.5meter high behind the couch.

 

[basscleaner]

Let me give you some comments for your initial room conditions and then for your attempts to improve the situation. Your room dimensions set is the first problem, which could determinate "bad things" for acoustical performance. This is due to your proportion between the length (6 m) and width (4 m) which is the cause of big spread of SPL for low frequencies (and not only) behavior. Peaks and dips SPL is the consequence of this. And you should to take into consideration Low range, midrange and high range separately, but with some intercauses between them. Important value for low range is space positions of your sources, in particular, it needs to know, where is placed so-called "effective center of low frequencies". You may to detect this point (but, of course, this is not the point significantly, but volume (s)) by means of Sound Pressure Level meter (NTI I recommend), if to move it along the face of your speaker. Why it is so important? Because the room dimensions set, room shape and this power point are determine the room response for low frequencies range. Then you may change your listening position like triangle: Listening point- space positions for your speakers (LP/SP) with the small (5-10 cm) changes for each component to discover the best position, where SPL distortions will be minimal and EQ may be effective. You no need to chase for symmetry. Good sound may be for different positions. Only after this you can operate with midrange and higher range to delete boominess for them. Attempts to overcome all the distortions and artifacts without this plan will only confuse you. After LF position determination you should work with balance between absorption and reflection proportion to get the best sustain. First reflections work will follows by it. I must warn you, that there may be situations, when dimensions set and your speaker model will conflict between them and you not succeeded in good sound problem solving in this case. But such cases are quite rare.

 

[Flaesh]

6th measurement
The dB level on SPL meter decreased by 2dB (down to 73dB).
The room is quite dead and a bit unpleasant to be in as its not as natural as one would like it to be.

Unexpected. Perhaps habit plays a role. It is also possible that the reverberation in the upper frequencies was perceived as liveliness..

For comparation, black - my room, with a bit of PET wool, yellow - friend's room, w\o any treatment.
Your tens of hertz decay very quickly, many would envy this. It's strange that the bass is so exaggerated.

p.s.: What are the actual dimensions of your room?

 

[nebunebu]

Thank you basscleaner and flaesh, I will take that into consideration.

I will give it a go optimizing loudspeakers position. But think i will do that once certain accoustic treatment is fixed.


I agree as when I became used to the a bit more dead room i feel like the speakers are playing better. Everything is tight and the imaging is actually it but more presence aswell. Mostly likely because sound waves dosent bounce back and forth endlessly.

The room estimate scientifically approach is 3x5 meters

 

[Wiredforsound]

Helm Holtz resonator along the roof line install using removable Command Strips.
Helm Holtz generator just means pine wood slats in a triangular shape. Slats vary in random spacing along generator.
Cover with material.
Easily removable, easy to build and light.
Your speakers are light on bass, these are bass traps, so as EQ is for bass mainly.
Room treatments are for everything else.
Acoustic panels to cover various frequencies must be made of different materials.
Each foam material has differing rates of absorption based on frequency and sound pressure levels.
So traps in line with mid to high frequencies must be of various materials placed on top of one another.

Funny people used to use home insulation in music rooms for homes at first, then they discovered that the fibres would change shape and align in different ways based on frequency and sound preasure levels. That's why they don't use it to damp speakers internally.

Had a book written by I think Floyd Toole or maybe his contemporaries on this subject.
Get that microphone off the short stand and onto a microphone boom stand.
It needs to be away from absorbent surfaces and room boundaries by 20" or even 24-36".
Pointing upwards towards the ceiling. If it's closer to a reflective surface the surface should be damped properly, based on the frequencies being measured, again damping material of various types to cover multiple frequencies.

Any way to change up speaker and seating position?
Your always better off acoustically lengthwise down the room, instead of across the room.