EQ filter calculation for not listed device

[schiff1108]

My device (RME ADI2 -DAC) is not listed in REW, but I would like to calculate the filters with REW.

I have tried the "generic" device. Results look ok, but I cannot copy the results as my device has limiations such as
- number of bands = 5
- gain is limited to -12 to +12
- each band is not support all frequencies.

Is there any way to set generic rules or to configure the paramters of a device?

I would like to understand this before I get in touch with RME.

 

[JStewart]

Let's see what we can get done....

- each band is not support all frequencies.

Looking at page 21 of what think is the correct OM you have 20Hz to 20kHz for each of the 5 bands if band 1 & band 5 are set to type "Peak"

------------------------------------------------------------------------------------------------------------------------------
User’s Guide ADI-2 DAC v1.8 © RME 21

12.2 Subpage Parametric EQ

EQ Enable
ON, OFF. Default: OFF.

Band 1 Type
Available settings are Peak, Shelf, High Cut and High Pass (Low Cut). All filters are adjustable
from 20 Hz to 20 kHz, at a Q of 0.5 to 9.9. Cut/Pass have a fixed 12 dB/oct filter steepness.

Band 2-4 Type
Not available, fixed to Peak.

Band 5 Type
Available settings are Peak, Shelf or High Cut. High Cut is
adjustable from 200 Hz to 20 kHz, at a Q of 0.5 to 5.0 and a
fixed 12 dB/oct steepness.

Band 1-5 Gain
Available settings are -12 to +12 dB in steps of 0.5 dB.

Band 1-5 Frequency
Adjustable from 20 Hz (200 Hz bands 4/5) to 20.0 kHz, in steps between 1 Hz and 100 Hz.

Band 1-5 Q
Quality factor is adjustable from 0.5 to 9.9 in bands 1 to 3, and 0.5 to 5.0 in bands 4 and 5, in
steps of 0.1 dB. This equals a bandwidth setting of 2.54 (0.5), 0.29 (5.0) and 0.146 (9.9).

------------------------------------------------------------------------------------------------------------------------------

- gain is limited to -12 to +12

Depending on the measurement to be corrected this may be a limitation. In particular a 12dB cut since its not uncommon to have 15dB peaks and higher in the Low Frequency (LF) region.
I've not noticed a limitation for filter cuts in REW but you can set a limitation for gains. See the top "ovaled" control on pic.
The RME ADI-2 OM also limits the filter Q to 10, so uncheck the box in the 2nd oval "Allow narrow ..."

- number of bands = 5

As for limiting the number of filters you can keep the first 5 checked and just uncheck the rest, as in this screenshot:

Misc:
If you have a really strong peak you could use two of your filters at the same center frequency.
On the REW EQ filters page (in above pic) you can change the type to manual from auto and enter your own values. Results are shown real time.
You might also address a narrow peak by applying smoothing to the measurement to be EQ'd.
The "Moving Mic Method (MMM)" may be a good way to get your measurement for EQ as it will also "smooth" the response over the measurement area.

Hope this helps get you closer.

 

[schiff1108]

Thanks @JStewart.
Unhappily I was short on time to quickly look on your help. Well, think I understand most ideas and will have a closer look and do some testing.

But one question remain. A more academic question.
How to really add a new device to the list? Is programming required or "just" configuration to estabilish the rules? Who can do this?

 

[John Mulcahy]

Yes, programming is required, by me. A configurable equaliser is on the todo list, along with 509 other items.

 

[schiff1108]

understood

 

[JStewart]

along with 509 other items

Good luck with that.

 

[schiff1108]

Depending on the measurement to be corrected this may be a limitation. In particular a 12dB cut since its not uncommon to have 15dB peaks and higher in the Low Frequency (LF) region.
I've not noticed a limitation for filter cuts in REW but you can set a limitation for gains. See the top "ovaled" control on pic.

I do not really understand the both fields on Max Boost. I have the impression that they apply for plus gains and not for minus.

As for limiting the number of filters you can keep the first 5 checked and just uncheck the rest

This is not a real solution, isn't it?
But what I have learnt by experimenting is that I can have a combined solution of auto and man filters and that a new match keeps the man filters fixed while taking them in consideration re-calculating the auto filter values.
I have also observed that increasing the Flatness Target is decreasing the number of suggested filters.

You might also address a narrow peak by applying smoothing to the measurement to be EQ'd.

Not sure what you mean. Are you suggesting to go from 1/48 smoothing to 1/24 or even lower?

The "Moving Mic Method (MMM)" may be a good way to get your measurement for EQ as it will also "smooth" the response over the measurement area

Still on my list of things to be done.

Conclusion: REW has already helped my to improve my listing experience in my difficult listening=living room with windows, etc. Especially that I was able to determine two different filter sets for left and right channel was very useful.
Again. My motivation to understand automatic calcualtion of filters is more an academic one.

 

[schiff1108]

Yes, programming is required, by me. A configurable equaliser is on the todo list, along with 509 other items.

I am looking forward playing around with the configurable equaliser and I am more than happy to give some donation for this great piece of software.

 

[JStewart]

I do not really understand the both fields on Max Boost. I have the impression that they apply for plus gains and not for minus.

That's correct. The limitation is with the RME equalizer. +/-12dB. So you can limit the boost within REW, but you can't exceed the 12dB cut limit of the RME. That's why I also mentioned "stacking" filters at the near the bottom of the post.

This is not a real solution, isn't it?

I don't think I understand the question...
The RME equalizer has 5 bands. Why would choosing generic eq and unchecking all but 5 bands not work?
The 5 can be set to auto or manual depending on measurements and needs.

Not sure what you mean. Are you suggesting to go from 1/48 smoothing to 1/24 or even lower?

Yes, possibly, as a work around to deal with a narrow peak and due to the filter band width limitation of the RME. Not intended for filters that won't exceed the limitations of the equalizer.
I mentioned MMM because it can perhaps, depending on measurements, be a better alternative.