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TOPIC: How does Acourate DRC work exactly?

How does Acourate DRC work exactly? 6 years 2 months ago #9861

  • John Ashman
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Mainly curious how it compares to DEQX and Audyseey. With DEQX, you measure the speaker, make the correction curve for time, phase, driver response. And THEN you look at room response. With Audyssey, you're looking at the speaker/room combined, though with a pretty crappy target curve pushed on you.

Would like something that works more like DEQX, with the ability to correct phase/time errors and deal with the room and speaker separately in some cases.
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How does Acourate DRC work exactly? 6 years 2 months ago #9862

  • john.reekie
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Hi John, AcourateDRC does correction at the listening position. It does allow you control over the target curve but as I understand it corrects minimum phase only, not excess phase. I believe the full version of Acourate may do more of what you want (not entirely sure).

For linearizing loudspeaker phase, you could look at rePhase. I hesitate to talk about "correcting timing errors" as I'm not entirely sure what that means (?) but it does seem to do a nice job with phase :) You can set up multiple correction banks in rePhase so that might be an interesting way to do first speaker correction and then room correction.

These may help:

www.minidsp.com/applications/digital-roo...rrection/acouratedrc
www.minidsp.com/applications/advanced-tools/rephase-fir-tool

Here's how I plan to try all this out (first diagram):

johnr.hifizine.com/2013/08/the-tandem-subwoofer/

J
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?
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How does Acourate DRC work exactly? 6 years 2 months ago #9872

  • John Ashman
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Well, I guess I confused myself. What I really want is the full power of Acourate, and would pay for it, if it can be downloaded into OpenDRC.

Looking for more than just DRC, though DRC is better than nothing. I'm not sure how Acourate, the full program applies to OpenDRC, but I believe it does correct the phase issues. I should but don't really speak the language that well. I'm more into the acoustic part than the geekery part.

I used to get into huge battles with Audyssey over how little they understood basic acoustics and how they provided no tools to fix their errors. Tomlinson Holman is kind of a brilliant idiot though, like Amar Bose, so I should have known better. When NAD wanted to use Audyssey, I quickly complained about it, so they ran it past Paul Barton who fixed the program, but only in NAD's implementation. Audyssey used a flat target curve that killed the based and shrilled up the highs. I think they've kinda fixed it in later generations.

So, basically, I want the ability to measure the speaker closely, then do a LF only repair of the lows and combine the results. And also do some averaging of multiple measurements. Another feature that would be ideal is the ability to dial back the correction curve in real time, to find the right balance between full correction and none.
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How does Acourate DRC work exactly? 6 years 2 months ago #9920

  • curryman
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Acourate is definately a very powerful tool and AFAIK also the full version of Acourate can generate FIR Filters for openDRC. You "just" have to define the max. taps (6144) and the correct samplerate (48kHz).

However the reason why Uli (the developer of Acourate and AcourateDRC) stuck to minimum phase with AcourateDRC is the limited length of the impulse response with the given number of taps. If you want to have a linear phase correction your impulse response will have to be non-causal and thus centered within the given time frame (6144 taps at 48kHz correspond to a duration of the impulse response of 0.128s). This further reduces the frequency resolution of the FIR Filter compared to a minimum phase correction. There are some reports that linear phase correction has the biggest effect on low frequencies.

I recommend having a look at rephase which does not provide "automatic" correction by (more or less intelligent) inversion of the measured response but in my opinion that is exactly it's strength ;) Manually editing the EQ (amplitude and phase) you'll get a very good feedback about what is possible and what is not possible with the given number of taps and you can end up with a good hybrid (mixed minimum/linear phase) equalization.

Best regards, Daniel
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How does Acourate DRC work exactly? 6 years 2 months ago #9924

  • John Ashman
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Thanks, that it very helpful. I am less concerned about phase anyway, but Rephase sounds like a fun toy to try first.
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Max Taps. Was How does Acourate DRC work exactly? 5 years 8 months ago #12143

  • bobkatz
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I am "tap-math" deficient and would appreciate some help.

I already own Acourate and am using it for a computer-based Convolver with Acourate Convolver (best-sounding dsp on earth!). I am soon to purchase an Open DRC Sharc box as a backup for the computer. Can't bear to lose my loudspeakers if a computer goes down, if you know what I mean ;-). I am confused about the max taps avaialble. On page www.minidsp.com/products/opendrc-series/...c-4x8-plug-in-detail Says that there are a total of 10300 taps, or 2048/ch. which comes to 5+ channels, which is weird, since it supports 8, so obviously resource allocation is not 100% linear and some taps are being held back.

For two channels, people are saying there are 6144 taps per channel which comes to 12288 total. Perhaps the math is different when you set it up for two channels? Thanks for the help.
Last Edit: 5 years 8 months ago by bobkatz.
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Max Taps. Was How does Acourate DRC work exactly? 5 years 8 months ago #12144

  • dreite
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Bob,

The OpenDRC box only supports two-in, two-out operation so you'll select the OpenDRC 2x2 plug-in and not the miniSHARC plug-in. It's more straightforward and doesn't have the somewhat confusing arithmetic description of the miniSHARC plug-in. :)

Take a look here:

www.minidsp.com/images/documents/Product...%202x2%20plug-in.pdf

Good to see you here. My copy of "Mastering Audio" still occupies a well-used spot on the coffee table. :)

Cheers,

Dave.
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Max Taps. Was How does Acourate DRC work exactly? 5 years 8 months ago #12146

  • bobkatz
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Dear Dave:

Good to see you here. Glad you enjoyed my book. Just before I saw your reply, Uli had just pointed me to the 2x2 plugin and clarified some of those questions on the taps. I can clearly use two OpenDRC boxes, one for the mains, one for the subs. The total cost is only $140 more than two mini-sharcs anyway and I guess the FIR power (number of taps) of one Open DRC 2x2 plugin is greater than any other sharc option at the Mini dsp site. Any tips on managing switching back and forth between programming one or the other via USB so as not to get confused? Can I keep both plugged in via USB and will the plugin identify which box I am talking to?

Best wishes,


Bob
dreite wrote:
Bob,

The OpenDRC box only supports two-in, two-out operation so you'll select the OpenDRC 2x2 plug-in and not the miniSHARC plug-in. It's more straightforward and doesn't have the somewhat confusing arithmetic description of the miniSHARC plug-in. :)

Take a look here:

www.minidsp.com/images/documents/Product...%202x2%20plug-in.pdf

Good to see you here. My copy of "Mastering Audio" still occupies a well-used spot on the coffee table. :)

Cheers,

Dave.
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Max Taps. Was How does Acourate DRC work exactly? 5 years 8 months ago #12203

  • devteam
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Bob,

In answer to your question, 2 x OpenDRC will indeed carry a lot more taps than a miniSHARC but note that you may want to purchase a USB switch (i.e. with physical buttons) since you wouldn't be able to have both units "online" and connected to the PC. The plug-in isn't smart enough to build configurations based on a connected unit. See the process of loading/synchronizing a file from the website. It will give you an idea of what we mean.

Hoping this info helps.

DevTeam
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