More > JRiver Media Center 27 for Windows

Feature Request: Equalizer Improvements

<< < (5/9) > >>

mattkhan:
I measured the effect of Q on high/low pass filters in MC and can say that jriver Q = actual Q / sqrt(2)

i.e.

jriver Q= 0.707 is a conventional Q=0.5
jriver Q = 1 is a conventional Q = 0.707
jriver Q = 1.414 is a conventional Q = 1
jriver Q = 2 is a conventional Q = 1.414

and so on

conventional in this case being the RBJ audio cookbook implementation of a variable Q high or low pass filter (assorted references online, one copy can be found at https://github.com/libaudioverse/libaudioverse/blob/master/audio%20eq%20cookbook.txt)


--- Code: ---    omega = 2*PI*frequency/sampleRate
    cos    = cos(omega)
    sin   = sin(omega)
    alpha = sin/(2*Q)                                   

LPF:            H(s) = 1 / (s^2 + s/Q + 1)

                b0 =  (1 - cos)/2
                b1 =   1 - cos
                b2 =  (1 - cos)/2
                a0 =   1 + alpha
                a1 =  -2*cos
                a2 =   1 - alpha

HPF:            H(s) = s^2 / (s^2 + s/Q + 1)

                b0 =  (1 + cos)/2
                b1 = -(1 + cos)
                b2 =  (1 + cos)/2
                a0 =   1 + alpha
                a1 =  -2*cos
                a2 =   1 - alpha

--- End code ---

I do not know how this is implemented in jriver but it's definitely not going to give the results that anyone expects when using an external filter design tool unless they know to scale Q accordingly.

wer:
If you want a good chuckle, try measuring the effect of the 12k, 14k, and 16k sliders in the GEQ.

mattkhan:

--- Quote from: wer on January 04, 2021, 05:00:07 pm ---If you want a good chuckle, try measuring the effect of the 12k, 14k, and 16k sliders in the GEQ.

--- End quote ---
it seems fairly normal here, some warping as it gets closer to nyquist but that seems unavoidable & it seems to behaves the same as a peaking filter with the same bandwidth. Does it behave differently for you?

wer:
No, you're capturing how it performs.

It just demonstrates those three sliders are so close together as to be superfluous.

We have what is effectively an 8-band eq, not 10.  With insufficient resolution at the low end, and insufficient resolution at the high end.

mattkhan:
right yes, that is pretty pointless

a simple graphical interface that lets you manipulate peaking and shelf filters would be so much more useful

Navigation

[0] Message Index

[#] Next page

[*] Previous page