I have no idea

[Jeroentje]

I don't think I'm doing something right. And I have absolutely no idea what I'm doing.

Attached the graphs that I'm creating. Red-line shows measurement mic on the listening position. Green one in the corner.

The situation:
A desk in a room. Room is about 15 x 15 feet. Desk is situated at one of the walls. On top, two speakers. About 4 feet apart.
The room is not treated very well. Behind and beside the speakers (on the walls) are self created absorbers. Backwall has no treatment. Ceiling; no treatment. Curtain in front of the window (on one wall left of the listeningposition)
Listening position is about 4 feet from each speaker so should be ok. But all of this is not realy important because I'm not getting the best results in this room. I'm trying to understand the software and get a good measurement so that I can use the software later on correctly in the attic were I'm building a home cinema at the moment. It's experimenting for later.

First measurement (red line) is at the listening position. Smoothing is at 1/6. It's not flat. Oke, no problem, wasn't expected to be flat. But lowest point, 228Hz is 75.59dB and highest point is 78.94dB at 128Hz. In my eyes, that is very little and can't be oke. I expected a bigger difference.

Green line is second measurement, also smoothed at 1/6. Microphone is placed in the abolute fartest corner. Litteraly half an inch out of the corner. On purpose to get a measurement that would be very different and shows up much more bass builded up in the corners or some other results.
Yes, there is a peak of 78.40dB at 53Hz. And the lowest is 75.68dB at 45Hz. But come on. The mic was about 10 feet away from the listening position. Levels were not altered before the second measurement.

I expect, even at the first measurement, big 'troubles'. There is far too less treatment in the room. If I snap my fingers I can hear sound bouncing all around.

Something is not right here. Am I measuring the room or my soundcard? Or am I doing something else completely wrong?
I have no idea what I'm doing wrong. Pherhaps, I might even have no idea what I'm doing at all. Red a lot of documents and seen a lot of YouTube-movies and my measurements don't add up to what I'm expecting. Come on; so much level at 25Hz can't be right for an poorly treated room

Used equipment?
- PC (duh)
- Two Mackie MR524 speakers
- Soundcard used; D&R Webstation
- Microphone, cheap- Behringer ECM8000 (It's an experiment, I'm not going to invest heavy into a microphone if I can't get it to work)

 

[EarlK]

You're right ( your captures are a mess ) and no-one will really know why.

It's unlikely that anyone here can help you because it's almost guaranteed that no-one who frequents this forum understands ( or is familiar ) with the signal routing of that D&R webmixer ( and what you've done to arrive at your squiggles ).

Get yourself a simple 2 chnl (in ) x 2 chnl ( out ) USB soundcard that has at least 1 mic pre-amp ( such as the Focusrite 2i2 ) and then try again.

 

[Jeroentje]

I do have a focusrite scarlet 6i6 lying around somewhere. Will go have a look and install that one and true again

 

[John Mulcahy]

One possibility is that you have mistakenly saved a listening position measurement as a soundcard cal file. Posting the mdat file for the measurements may give some clues.

 

[Jeroentje]

Offcourse, haven't saved my measurements.....

But calibrationfile is a bit to large to post I think. It consists of 24000 lines. Here are a few:


-----


* Soundcard Calibration data saved by REW V5,19
* Source: Input device not selected, no input selected, R, volume: no control
* Format: 256k Log Swept Sine, 1 sweep at -6,0 dBFS Using an acoustic timing reference
* Dated: 1-jun-2021 20:13:39
* Note: DR Webstation 01062021
* Sample Rate: 48000
*
1,831 -9,294 140,105
2,031 -8,288 132,047
2,231 -7,307 122,814
2,431 -6,540 115,734
2,631 -5,883 109,403
2,831 -5,327 103,751
3,031 -4,837 98,608
3,231 -4,412 93,955
3,431 -4,037 89,692
3,631 -3,709 85,804
3,831 -3,417 82,206

...............


23991 -87,705 -29.793,203
23992 -76,254 -29.818,725
23993 -71,372 -30.189,123
23994 -75,767 -30.247,859
23995 -84,826 -30.569,062
23996 -74,530 -30.755,439
23997 -77,944 -30.661,078
23998 -85,840 -30.587,695
23999 -63,404 -30.798,637
24000 -87,774 -30.920,377

 

[Jeroentje]

Fidled around. When I "check levels" in the preferences-box, I notice that there is an output of pink noise. But even with the Mic closed, there is a "in"-level and also a "Ref in"-level. Both input-levels drop down when I shut down the fader. Fader of the mic is not even open. So how can there be an input level when the mic is not operated? That shouldn't be possible.

Will try the idea of EarIK and get the Webstation out of the loop and replace it with my Focusrite

 

[John Mulcahy]

The cal file shows "Input device not selected, no input selected", which would mean the input is likely to be whatever is the Windows default input. Selecting the actual input device, input, output device and output that are to be used is strongly recommended.

 

[Jeroentje]

Still have no idea what I did wrong then. But did a bit of reading. pulled out my old laptop, simple external sound card and hooked an amp up with a hdmi-connection.

And I’ve got some results today. Not happy with them, but that’s another story. I know where the problems of my room are (5 second delay-time at some frequency’s for instance) and massive dip in the lower part up until 200 hz.

So, there is still some work today. But it’s a start

 

[John Mulcahy]

5 second delay-time at some frequency’s for instance

Are you still measuring the 15 x 15 foot room you originally mentioned? If so 5 second decay is unlikely unless it is a bare-walled concrete basement. Features that don't decay may be noise or mains hum.

 

[Jeroentje]

I moved to the new room. Nothing on it except speakers, furniture for equipment, small tv (all at one side) and a simple chair in the middle.
nothing more, the rest are flat walls. So the seconds of decay are explained by that.