Jump to content
IGNORED

Article: Dirac Live 2 Digital Room Correction Software Walkthrough


Recommended Posts

Recently hired Mitch to optimize my system.  Intelligently applied DSP is the most important change to my system since I started with this hobby in the late 1970s while studying electrical engineering in college.   Mitch ended up using Audiolense.   We’re on the second set of filters, trying to dial in the “perfect” timbre for my taste.  Over the years like most audiophiles I made many changes, most resulted in incremental Improvement, but this is the first true game changer in how my system sounds.   Real science, measurable results, very talented, easy to work with remotely.   What else can I say.  

Audio Alchemy DMP-1 / Roon / Berkeley Alpha RS 2 / Constellation Monos / TAD R1s

Link to post
Share on other sites
2 minutes ago, pga said:

Recently hired Mitch to optimize my system.  Intelligently applied DSP is the most important change to my system since I started with this hobby in the late 1970s while studying electrical engineering in college.   Mitch ended up using Audiolense.   We’re on the second set of filters, trying to dial in the “perfect” timbre for my taste.  Over the years like most audiophiles I made many changes, most resulted in incremental Improvement, but this is the first true game changer in how my system sounds.   Real science, measurable results, very talented, easy to work with remotely.   What else can I say.  

Hey PGA, great to read about your experience with Mitch and the results. It mirrors my experience. DSP has come a very long way and in the right hands it’s amazing. 

Founder of Audiophile Style

Announcing The Audiophile Style Podcast

Link to post
Share on other sites
  • 3 weeks later...
  • 3 weeks later...

Hi Mitch,

 

I recently used the VST plug-in "Dirac Live 3 Multichannel" with "Jriver Media Center" as the host application. The output of Dirac goes into Jriver DSP where I have bass management, digital crossovers, and multi-subwoofer optimization filters (MSO software).

 

I did a  9 measurement cube with an Earthworks M30 mic (8 corners plus center), set target responses as needed, and generated a filter set.

 

This the BEST my system has ever sounded plus it's quick and easy (not counting the separate use of MSO and REW to generate my subwoofer line array filter set).

 

Dirac Live Bass Control for optimizing multiple subwoofers is in the works and may be able to replace my use of MSO. I'm a bit skeptical as MSO is truly amazing in what it can achieve.

 

Dirac Live Bass Control Illustration (just happens to be how my subs are arranged). No rear subs in my case.

 

spacer.png

Link to post
Share on other sites
5 minutes ago, hulkss said:

Hi Mitch,

Here's a couple pics of the room and my first quick try with Dirac playing and measuring through Jriver DSP.

I had to switch the surround channel assignments into and out of Dirac and adjust the LFE test signal output level -10db to get correct results.

 

 

2020-09-07.png

Speakers.jpg

Seats.jpg

Love it!

Founder of Audiophile Style

Announcing The Audiophile Style Podcast

Link to post
Share on other sites

Hi Mitch,

I have a 7-meter-wide subwoofer line array consisting of one central Infinite Baffle (IB) Subwoofer, flanked by four Epik Empire subwoofers, and two Klipschorn corner-horns. Fourteen 15-inch drivers in all, driven with 5 amplified input channels: one for the IB, one for each K-Horn, and two channels for the two Epik pairs. The corner horns play L & R  channel content above 80 Hz and are part of the subwoofer array below 80 Hz.

Here is the Jriver DSP Set-up (all 64 bit processing with 24 bit, 48 kHz signals):

DTS Neural UpMix is a VST3 Plug-in inside of DDMF Metaplugin64 v 3.4.3. That's what I could get to work properly.

Next Jriver PEQ2 swaps side and rear surrounds, then into the Dirac plugin.

I attached a list showing what makes up the somewhat confusing audio channels and then the Jriver DSP.

The last image shows the Robert Bristow-Johnson (RBJ) parametric equalizer “bi-quad” filters from MSO that are in the last image of Jriver Parametric Equalizer DSP.

 

As far as I know an unlimited number of filters can be entered into Jriver DSP.

 

2020-09-07 (1).png

2020-09-07 (2).png

Channels.PNG

2020-09-07 (4).png

2020-09-07 (5).png

2020-09-07 (6).png

2020-09-07 (8).png

Filters.png

Link to post
Share on other sites
38 minutes ago, mitchco said:

Wow @hulkss that is some engineered system you have there! Like I say, I would love to hear it!  14 x 15" woofers, that must be some slam!

 

Just in case you did not see it, JRiver 27 will have VST3 support: 

https://yabb.jriver.com/interact/index.php/topic,126706.0.html 

Still likely need the metaplugin...

 

Thanks for sharing!

 

The software can be problematic. I loaded an update to Metaplugin a few months ago and it gave me trouble so I am holding at v3.4.3 for now. I'll try updating again when Jriver 27 is ready. Thanks for the VST3 heads up.

 

Sadly, it's a rare audio mix that has the dynamic range to sound truly live and use the full potential of this system.

Link to post
Share on other sites
  • 1 month later...
On 4/17/2020 at 12:35 AM, mitchco said:

I don't know how Dirac is implemented in these h/w devices, but on a PC you typically use 65,536 taps per channel which gives full low frequency control. Remember the primary purpose of DRC is to correct the low frequencies below Schroeder. So my review of Dirac 2 is only in the context of using Dirac on a PC.

 

Hi @mitchco

 

From the quoted, are you saying that Dirac Live 2 on PC (that you used and reviewed) is using 65k taps per channel?

 

Since you gave Dirac Live 2 on PC a good review on its performance, including correcting low frequencies below Shroeder, then can we assume this PC version is using 65k taps per channel?

 

Thanks !

Link to post
Share on other sites
6 hours ago, mitchco said:

In the case of Dirac, on the PC, we don't know how many filter taps are used as Dirac uses "mixed phase" filters which are a combination of IIR filters for low frequencies and FIR filters above a certain frequency. It is a black box

 

Thanks @mitchco and all is noted.

 

I guess despite being a black box, from your detailed analysis and verification, it's doing a good enough job to be in the "state of the art" category with Audiolense and Acourate. So number of taps isn't worth (me) worrying about.

 

The Bass Control feature coming will be cool, to allow Dirac Live to handle DSP crossover to sub/s

 

Link to post
Share on other sites
  • 1 month later...
  • 2 weeks later...
On 12/12/2020 at 12:57 PM, Ultrasonic said:

I believe Dirac Live actually applies boosts of up to 10 dB

or even more. it reserved 12.5dB for me

 

On 12/12/2020 at 12:57 PM, Ultrasonic said:

It's possible that the DL behaviour is different when implemented on PC/Mac but my guess would be that the behaviour is the same

using vst version

Link to post
Share on other sites
9 hours ago, vavan said:

or even more. it reserved 12.5dB for me

 

I think the headroom to allow and the maximum boost applied at an individual frequency are slightly different things, principally because the phase changes introduced can also increase peak levels. On the other hand music signals are usually a complex mix of frequencies rather than a simple tone, so a 0 dBFS signal at the frequency of max boost would be very rare.

 

miniDSPs don't automatically 'reserve' any headroom by the way, so there is no equivalent I can give you to compare.

Link to post
Share on other sites

Here is a loopback sweep through JRiver of Dirac's correction filter used in this article on top. On bottom is another DSP product using a FIR correction filter for the same speaker (both left channel). I drew a red line just above the FIR correction filter as I know that is 0 dBFS as I can inspect the FIR filter directly and measure it's peak amplitude in another application.

 

Dirac correction filter top DSP correction filter bottom for Purifi SPK4.jpg

 

As I can't inspect the Dirac correction filter directly, or know what is going on in the DiracLiveProcessor (i.e. is it "just" a convolution engine or is there additional processing?) it is difficult to draw any real conclusions. The only conclusion I can draw is that the two filters are going to sound different. Note some other DRC/DSP software products provide the user the capability of adjusting how much correction is applied.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×
×
  • Create New...