What I ham having a hard time understanding how he arrives at the numbers he plugged in adding 4db.
Existing BREAKPOINTS
30 0
50 0
70 -0.8
100 -2.4
140 -4.9
200 -6.8
300 -7.8
400 -8
700 -8
16000 -8
Revised Breakpoints are below in his tutorial. How does the math actually work? I can see for example 400 was -8, now it's -12. But 70 was -.8 now it's -1.05, not -1.20. Is it not simple math equation? How do you arrive at the values to plug manually if simple math is not the case?
I'm not quite sure of the details involved here... but there are two things you need to be aware of when creating custom target curves.
The first is that, when you create a Target Curve, the result is smoothed by the software, and cannot contain "sharp steps" or changes that are too abrupt.
In technical terms what you are getting is "a curve that is fitted to the points you entered".
(I don't know the exact technical details of how Dirac Live does their smoothing... and there are several standard ways of doing so.)
Therefore the results you get, while they "follow the points you entered", may not follow them exactly.
(Specifically you will probably find yourself unable to create really sharp narrow peaks or notches or sharp steps up or down; there are also limitations on the overall range of corrections allowed.)
(Also, since there cannot be "s sharp step where the curtains are" the Target Curve is going to be "bent" such that it smoothly meets the ends of the measured curve at each curtain.)
The second thing is that the software is going to normalize the overall level.
So, for example, you cannot make a certain channel louder merely by "raising the entire curve".
The Dirac software is going to create a frequency response curve of the shape you request...
But it is then going to adjust the relative level of each channel according to its measurements...
So, for example, if you were to simply take the default Target Curve, and raise it up along its entire length by +4 dB for only one channel, the result may NOT be that channel being 4 dB louder than the others.
(The level trims are there so you can change that part of the result after the filters are calculated.)
Since REW does things a different way, both the way it takes measurements, the way it allows you to enter corrections, and the way it calculates its filters, will be different than with Dirac Live.
Another more important thing to remember is that WHEN YOU CREATE A TARGET CURVE IN DIRAC YOU ARE *NOT* ENTERING CORRECTIONS WHICH YOU WANT TO BE APPLIED.
Dirac Live measures your system, compares those measurements to the Target Curve, then creates correction filters that correct your system to match the Target Curve.
The provided default Target Curve is "a final frequency response which most users find makes their system sound flat and accurate".
(As it turns out, a system that is actually adjusted to measure flat tends not to sound right, so various standards have been developed for "what response curve sounds flat".)
However, WHEN YOU CREATE A TARGET CURVE YOU ARE TELLING DIRAC LIVE WHAT FREQUENCY RESPONSE YOU WANT TO HAVE FOR YOUR SYSTEM.
So, in effect, when you adjust the Target Curve by creating a custom one, your adjustments will be added to whatever corrections Dirac Live already considers necessary.
So, for example, if your system has an actual measured dip in response of -4 dB at 440 Hz...
You DO NOT want to apply a 4 dB boost to the Target Curve to correct it...
If you leave the Target Curve AS IS, Dirac will take its measurements, note the -4 dB dip, and calculate a correction filter to correct it.
The only reason to edit the Target Curve is if you find the correction calculated by Dirac doesn't satisfy you...
(Either because it seems to have failed to take something into account... or simply because you prefer for your system to sound slightly different.)
Also note that Dirac Live uses a slightly different way of taking measurements than REW... so results may or may not vary considerably between them...
Dirac then presents you with a graph showing the results of its measurements...
And a "visual representation" of the corrections it plans to make...
And a second "visual representation" of what it expects the corrected response to be...
Note that this final graph is based on the information which is available to the software and is not actually measured...
Therefore, since there are probably minor details about your system and room that Dirac could not precisely determine, the results will also probably be at least a tiny bit different that the graph it displays.
(Room correction is not nearly as simple mathematically as "measuring twelve inches then cutting off two inches".)
What I ham having a hard time understanding how he arrives at the numbers he plugged in adding 4db.
Existing BREAKPOINTS
30 0
50 0
70 -0.8
100 -2.4
140 -4.9
200 -6.8
300 -7.8
400 -8
700 -8
16000 -8
Revised Breakpoints are below in his tutorial. How does the math actually work? I can see for example 400 was -8, now it's -12. But 70 was -.8 now it's -1.05, not -1.20. Is it not simple math equation? How do you arrive at the values to plug manually if simple math is not the case?
What I ham having a hard time understanding how he arrives at the numbers he plugged in adding 4db.
Existing BREAKPOINTS
30 0
50 0
70 -0.8
100 -2.4
140 -4.9
200 -6.8
300 -7.8
400 -8
700 -8
16000 -8
Revised Breakpoints are below in his tutorial. How does the math actually work? I can see for example 400 was -8, now it's -12. But 70 was -.8 now it's -1.05, not -1.20. Is it not simple math equation? How do you arrive at the values to plug manually if simple math is not the case?
BREAKPOINTS
30 0
50 0
70 -1.05
100 -3.6
140 -7.35
200 -10.2
300 -11.7
400 -12
700 -12
16000 -12
Example
Reading through the link you provided, I believe your answer lies in this section from the article:
“The custom target curve will typically look like a ski jump. There will be a “hill” on the left. Then there will be a downward slope, and at the bottom of the slope, the ski jump will level off. The “hill” starts at a level of 0dB and remains flat at 0dB until the one-octave-below- crossover point (50Hz in this example), and then gradually slope downwards through the crossover point until it reaches the one-octave-above-crossover point (200Hz in our example), end then level off and remain flat to the upper correction limit”
The -4dB (for a total of -12dB) point is starts at one octave higher than XO an remains -4 dB until HF limit. Between the XO (100) and the one octave higher (200), there is a “ski jump” not a sharp cliff. Hence the numbers you see. I think the authored “eyeballed” those numbers to fit a desired shape but you can be more mathematical about it if you like.
Last Edit: Oct 20, 2021 21:46:44 GMT -5 by unsound
I am coming from an Anthem Statement D2V with ARC room correction which was a bit different. What I miss was is the ability to adjust the Bass and Treble up/down just once in the tone setting.
I see/read that having Dirac enabled as the speaker preset makes the tone level adjustments temporary which is why I am trying to understand if it's possible to tweak things a hair with a curve adjustment.
The guide made it seem that editing the text file made it easier than using the sliders in Dirac. Not sure how you can "see" what the slope looks likes without viewing it in Dirac. That sort of defeats the purpose of what I read the tutorial to infer?
