Dirac Live is a feature rich room correction system that issupposed to help you achieve the best sound possible by measuring and accountingfor frequency response and impulse response issues. Unlike most room correctionsystems that use an outboard piece of gear, so every source in your system hasroom correction applied, Dirac Live only works when using your computer as asource.
dirac live room correction suite 17
The software works on both PC and Mac, and is split into two distinct pieces, a livecalibration tool and an audio processor. The calibration tool guides you throughmicrophone placement and measurement steps, and then the audio processor handles all of the, well, processing. The software suite supports multiple measurement positions in orderto weed out any single-position anomalies and focus on consistent acoustic issues found across multiplemeasurement locations. It also supportsup to 8 channel of audio and up to 24 bit resolution at 96Khz sampling rate, so you are fine to use it for Blu-ray playback.One of the big reasons Dirac is so proud of this system is that not only doesit help achieve a flat frequency response, but also corrects time domain issues. Ensuring that the sound from each speaker hitsboth of your ears at the same time and decays quickly (but not too fast) is critical to proper stereo imaging andoverall clarity. This system uses a look-ahead buffer to modify each track tomake sure each individual frequency arrives at your ear at the same time. Overall, this is a pretty cool system, but there is only so much an active solution can do so this isn't a substitute for passive room treatments.
Swedish digital audio pioneer Dirac unveiled the Dirac Live Active Room Treatment, the latest feature in the Dirac Live audio room correction suite, addressing bass resonance and room decay time for cleaner, tighter bass reproduction.
How much tilt? The scientific research that Sean Olive (and earlier Floyd Toole) conducted over years shows that a slope of 20 Hz to around -8 to -10 dB at 20 kHz is what most listeners prefer as neutral sound. A high level overview of that can be found in, The History of the Harman Target. While the overview also discusses headphone target curves, which have the same preferred target (transfer function) as loudspeakers in rooms, it also discusses loudspeaker target preferences. More importantly, there are a listing of AES papers that one can get the details on. One example is the Subjective and Objective Evaluation of Room Correction Products:
At this stage, I just wanted to show that Dirac works in the time domain. Given multiple measurement locations, one can understand that the sound and reflections arrive at different times and in different ways depending on the mic location relative to the loudspeakers. Using the concept of superposition and what we know about the physics of how standing waves respond in a rooms, we can work out the pattern and therefore correct for a wider sweet spot, which is what the 17 measurements are about. Dirac knows the phase relationships between the measurements plus taking the speakers as a pair into account, is used to calculate the correction filter.
Dirac was able to extend the low end frequency response in my room to below 30 Hz. -3 dB down at 22 Hz for the left speaker (as it is more in the corner of the room) and 28 Hz for the right speaker, as it is almost center in the room and does not get the corner boundary reinforcement. Compare that to -3 dB down at 32 Hz on the left and 45 Hz for the right speaker without correction.
I did not try Dirac 1.x, so have no way of comparing other than reading through the Dirac 1.x 42 page manual. I must say Dirac has greatly simplified the use of their room correction software for Dirac 2. I did not have to open a manual, I just started using it. I found the improvements made to my loudspeakers in my room by Dirac were audible to my ears and measurable in a positive way. Recommended.
I understand digital speaker correction which is what basically Dirac is doing at higher frequencies but I can not understand how the interaction of bass frequencies with room modes can be corrected by just altering the woofer output (past a single point in space). So I am looking forward to learn more about active bass management!
Understanding room correction is complicated A separate article is required to get though it all and I am contemplating writing one. In a nutshell, good room correction software will take an acoustic measurement and extract the minimum phase response and since speakers are minimum phase devices, correcting the frequency response will also correct the phase response. However, that is only half the picture as there is the room to deal with, which is what Dirac calls mixed phase or others call it excess phase, which includes room resonances and reflections.
And in the time domain, we know what the ideal speaker target is by looking at the timing (i.e. step) response of an "ideal" minimum phase speaker. So... the room correction software corrects the time domain to follow the ideal minimum phase target. You can see that if you have my book or some of the articles here at AS show that as well. But the trick is that this is wavelength dependant, so at low frequencies, the correction time window is long (like 600ms for example) and as frequency increases the correction time window becomes shorter so above the rooms transition frequency we are looking at more of the direct sound plus baffle of the speaker. Often called frequency dependant windowing. In other words, at low frequencies, the room correction software has a large time window that corrects both the direct sound and reflected sound (i.e. room resonance) towards a target response. At high frequencies, it is mostly the direct sound because if we tried to also correct for mid-range and high frequency comb filtering room reflections, the high frequency response of the loudspeaker sounds like a dentists drill. This is how one can hear "over correction" in the high frequencies.
Thanks for your response, Toole and also in a similar version Geddes are proposing to use multiple subwoofers spaced over the room to allow wider zones of bass correction (with specific phase corrections). I wonder if that is something Dirac can do and if that leads to a significant improvement compared to standard 2 woofers/subwoofers? Of course that adds a lot of complexity to the setup both computational and room design wise. REW room simulator shows some benefits but I wonder how real these simulations are?
Yes, I have seen both Toole's, plus Todd Welti's presentation on multiple subs, and Earl's paper, plus Duke LeJeune's swarm system. All show positive benefit's but one still needs room correction to obtain the smoothest bass response based on experiments I have run with multiple subs and locations.
Even if your sub(s) are part of your two channel system (i.e. not using digital XO), room correction is still a major benefit, which is what Dirac does. However, the new Dirac Bass Management will provide further control, but also requires more than 2 DAC channels.
"I always wondered what my system would sound like in a room optimized for acoustics. Unfortunately I can not make my living room look like a studio. Instead I downloaded the trial version and tried it out. After two weeks it was hard to live without the room correction program from Dirac, the sound was more organic and natural to my ears. It is a lot of money but still worth every penny". 2ff7e9595c
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