JBL 104 BT initial measurements and EQ

[yewneek]

Following recent discussions with helpful members of this board, and finding the Youtube videos of Julian Krause very informative, I have concluded the preliminary investigation and equalisation/correction of my JBL 104 BT desktop monitors.

My methodology was to purchase and install a calibrated measurement microphone, from Sonarworks. Use this with REW and interfaced using a Focusrite Scarlett Solo 3rd Gen. I believe I followed the Moving Microphone Method, as outlined in the instructional method in the Youtube video by J Krause.

Please find the files attached with my results.

Comments and constructive critique welcome.

GB

The summary graph before and after.
Link to mdat files on mega.io

Below are the published findings from @amirm and from the JBL literature

JBL published FR graph

 

[staticV3]

Comments and constructive critique welcome.

Please use a vertical dB range of ~50dB for your graphs.
What you have currently (200dB top to bottom) hides all details.

Similarly, the frequency range is best set to 20-20kHz. REW has a button specifically for that in the bottom right-hand side corner of the SPL graph.

Edit: also helpful to align the two graphs to more clearly show the differences. In your case, I would align the two at ~125Hz (use the Align SPL function in REW).

Lastly, I would make sure that both graphs use a consistent line width. To do that, open the REW preferences, then Appearance, then turn off "Thicker traces for AVG".

 

[yewneek]

Presentation, but not the data! There's hope for me yet!

Cheers for the nudges. Duly noted.

GB

 

[yewneek]

Please use a vertical dB range of ~50dB for your graphs.
What you have currently (200dB top to bottom) hides all details.

Similarly, the frequency range is best set to 20-20kHz. REW has a button specifically for that in the bottom right-hand side corner of the SPL graph.

Edit: also helpful to align the two graphs to more clearly show the differences. In your case, I would align the two at ~125Hz (use the Align SPL function in REW).

Lastly, I would make sure that both graphs use a consistent line width. To do that, open the REW preferences, then Appearance, then turn off "Thicker traces for AVG".

How do I set the range of dB as asked? The range of results is outside 50dB even between 20-20kHz. What top to what bottom?

This is new to me and getting up to speed on technical stuff as a rookie technician is implicitly easy for those with the knowledge!
Cheers

GB

 

[staticV3]

How do I set the range of dB as asked? The range of results is outside 50dB even between 20-20kHz. What top to what bottom?

100dB top to 50dB bottom roughly.

 

[yewneek]

Ok, but how?
Here's a screengrab.

 

[staticV3]

Ok, but how?

 

[staticV3]

I downloaded the MDAT file. Here's how I would present the data:


Some notes:

• You said you followed the Moving Microphone Method, yet from the measurements it looks like you did a bunch of sweeps at different microphone positions, then averaged them.
• Post EQ doesn't really look any better than stock
• There's a pretty big trough in the midrange, even after EQ

 

[yewneek]

It may not be splendid, but I hope it's sufficient!

I'm going to measure some more stuff now.

Cheers for the tips!


GB