JBL M2 DBX4820 settings

[bubbleboy76]

Inspired by this thread http://www.audioheritage.org/vbulletin/showthread.php?39267-JBL-M2-DCX2496-settings, I wanted to try out the M2-crossover settings in my DBX4820.

I entered the settings from the document as closely as possible in the DBX. Due to PEQ-limitations, I had to move some of the individual driver settings into the input-part, but all of the EQs got in there actually (I had to remove the 3 high-Q PEQs around 200Hz, but those are probably not to be used in a M2-clone anyway according to pos).

DBX4820 can do 9 PEQ on each input, and 6 PEQ on each output.

Settings entered into the dbx attached.

[bubbleboy76]

DBX4820 settings continued...

[bubbleboy76]

Then, I measured the output from the DBX4820.
As a reference, I imported the original BSS measurements from rephase (based on pos settings document).

Measurements attached. Pretty close, EY?!

In the upper-channel, the EQ around 20Hz is wrongly affecting here, because at one point I had to move this to the input-section when I ran out of PEQs. I should move this back to lower-channel now, after I removed the 3 high-Q PEQs.

Any suggestions which setting I could try to change, to make it better? The discrepancy 12-18KHz I could not figure out which setting to modify to affect that part. Too late at night now maybe...

Note, BSS vs. DBX measurements are not perfectly matched and comparable in overall magnitude/gain level. But I tried to get them as close as possible when setting up the levels for measuring the DBX4820.

[bubbleboy76]

The difference of the original BSS settings with and without the 3 high-Q EQs around 200Hz attached.
Note, this is my import from rephase into REW, and might very well be wrong in some way.

[bubbleboy76]

Unfortunately, I do not have any M2 speakers... :banghead:

[ivica]

Unfortunately, I do not have any M2 speakers... :banghead:

Hi bubbleboy76,

Very nice presentation, so "ONLY" DBX4800 is missing.

Talking about M2, DD, 436x, 9x00....
"The journey of a thousand miles begins with one step."

Regards
Ivica

[pos]

Any suggestions which setting I could try to change, to make it better?
You might try do adjust the shelving frequency and Q/slope on both the LF and HF part.

Regarding the 20Hz EQ, I am not sure it is a god idea to put in on the input: IIR biquad implementations can be quite noisy with VLF EQs and it is better to limit any problem to the LF channel only.

[bubbleboy76]

I tried improving the settings today. I tested a lot, but most changes were not making it better.
I found one small improvement though, when changing to 4.5db/oct slope on the lower-channel shelf (from 6dB/oct).
The new curves are attached, and they are a little bit better aligned on magnitude-axis now.
I think I could live with these settings actually, close enough for me.

[pos]

:thmbsup:


Do you still have available EQ points for the 200Hz-ish corrections for those who have the original M2 cabinets?

[bubbleboy76]

I have one EQ left in lower-channel, and one EQ left on input.

Worthwile using 1 EQ for the 3? I can measure it, if you want to design it.