TOPIC:

hi all,

I'd like to introduce a software named Align2 : it can create PORC or DRC correction directly for OpenDRC. You can find it here : Align2
It is not so easy to use, there is no real manual but skilled people may try it anyway...

Cheers
jlo

@ JLO,

Very interesting work and thanks for sharing! Sounds like an announcement is in due.

Do you think that you'd have time to write a little short talk of how to use it? We'd be happy to advertise it.

Or maybe someone out there willing to start writing a little step by step?
We'll try to have a look at end of this week but we're quite swamped these days following few days of holidays.

Devteam

Hi,
in another topic I asked if the OpenDRC could be configured into 12288 taps to improve correction in lower frequencies. But up to now, such a possibility is not available. So for the subwoofer, I've arranged so to go through both channels of OpenDRC.
Here is a room with huge modes :
- measure before any correction (black curve, 1/20oct smoothed)
- calculate first PORC correction with Align2 and apply it onto channel 1
- measure with first correction (red curve) and calculate correction for channel 2
- apply second correction onto channel 2 and measure again (blue curve)
You can see that going through twice correction really improves the results.

Good stuff and thanks for sharing. We could see in the future how we could do that to combine all taps into one large FIR tap block...
Out of curiosity, have you tried using some IIR to tame some of these room moves? At that low frequency, an IIR might be easier...

DevTeam

have you tried using some IIR to tame some of these room moves?

Yes, IIR is certainly more efficient to deal with very low frequency room modes.
But the biquad implemented in OpenDRC show some distortions with notch EQ under 70Hz and mid to high Q (example : you can hear distortion when using a sine wave and an peak EQ at 55Hz, +6dB, Q=10 or even 49Hz, -0.1dB Q=12 !).
Problems is not seen with the subwoofer EQ but its Q is limited to 3 so not usable to damp room modes (a room mode has a behaviour similar to a biquad with Q of 7 or more).
I know that biquad implentation at low frequencies is allways tricky but are you planning an evolution ?

@ JLO,

As mentioned in an earlier post, the problem has now been solved with a new firmware available under the UserDownloads. Please have a look at it and thanks again for your very valuable feedback!

DevTeam

@ JLO,

I forgot to add.. Your software is a little gem that I think is missed in all these posts! There is a lot of potential and I'm sure that a LOT of our community members would benefit from learning from it! Let us see how we can build a little step by step app note on how to use it. We just did one for rePHASE. It will be published in few days. Time to build the same for Align2.

If you have any comments/questions, please email us as we'd love to hear from you.
DevTeam

Your software is a little gem that I think is missed in all these posts!

thanks a lot devteam. But especially to be thanked are D. Sbragion and M. Green, who developped DRC and PORC.

Let us see how we can build a little step by step app note on how to use it

Doing help files is not really my cup of tea, so if somebody is going to do a step by step note, I'll be glad to help. In this case, maybe it would also be clearer to separate Align2 into a new topic.

As mentioned in an earlier post, the problem has now been solved with a new firmware available under the UserDownloads

Great ! That's a good support from the minidsp team. I'll check it asap.

Sorry for the delay.
I checked the new firmware with improved biquads : bravo, it solves completely the distortion problem in lowest frequencies !
Thanks to developpers.

Jlo, glad to hear that it's working!

We've just setup a section for Align2 so we can let our community enjoy the real power of the Align2. Here is the app note for rePhase by the way.
www.minidsp.com/applications/advanced-tools/rephase-fir-tool

For Align2, I believe that we could do a lot simpler by focusing on a step by step. I'm sure that you'll have more ideas on how to improve the correction files based on your extensive experience.

DevTeam