JBL 305p MKii Boundary EQ

[PaperBoat]

The generic shelving filters in REW’s EQ window (absent Q option) is pretty much what-you-see-is-what-you-get in jRiver if you just keep the Q to the default 1.0 setting. It really only gets confusing when you use other EQ software that has a different equivalent bandwidth value by comparison like switching between JR and rePhase — I use both — where one must be cognizant in manually changing the Q to 0.707 instead.

So literally use your preferred center frequency and gain, but leave the Q as is i.e. as 1 shown in the graphic.

If you want to model any other Q value besides the default of 1, there’s a link to a handy conversion formula/calculator in the jRiver wiki pages covering the topic of Parametric Equalization.

But what would be the "center frequencies" if I want to set up PEQ with Q value 1; attenuation -3dB at 70Hz, and PEQ2 with Q value 1; attenuation -6dB at 70Hz IN JMC?

 

[ernestcarl]

But what would be the "center frequencies" if I want to set up PEQ with Q value 1; attenuation -3dB at 70Hz, and PEQ2 with Q value 1; attenuation -6dB at 70Hz IN JMC?

Sorry, if I wasn't clear... but the answer is literally up to you:

*above is just an example

There's no necessary reason why you should literally copy/clone the same exact shelving behavior from your monitor's internal shelving filter DSP. You need only use whatever gets you to a satisfactory audible and measurable result. So listen to bass heavy tracks (of both acoustic and synthetic music types and adjust while listening in real-time until you find a good "compromise") -- *alternatively, listen to burst tones while you slide upwards from sub bass to upper bass frequencies using REW's 'tone generator'. But a slow sine sweep up to 300Hz-500Hz should also work until the entire sweep sounds relatively more linear to your ears than without the EQ.

 

[witwald]

But what would be the "center frequencies" if I want to set up PEQ with Q value 1; attenuation -3dB at 70Hz, and PEQ2 with Q value 1; attenuation -6dB at 70Hz IN JMC?

As mentioned elsewhere, the appropriate "Q" setting seems to be 1 in JMC. That appears to provide a fairly standard-looking shelf response, as best as I can tell from their documentation. The only other parameter is the f0 center frequency. The shapes of the shelving filters are essentially designed to be the same, irrespective of the chosen attenuation. Hence, as per the example that I provided earlier, f0 = 180 Hz should work for all shelf amplitudes to closely meet the 70Hz specification. I've computed the shelf responses for –1.5, –3.0, –4.5, and –6.0 dB with f0 = 180 Hz, and the results are plotted below. If you look closely, you'll find that at 180 Hz each of the shelves is 1/2 of the specified amplitude.

 

[PaperBoat]

As mentioned elsewhere, the appropriate "Q" setting seems to be 1 in JMC. That appears to provide a fairly standard-looking shelf response, as best as I can tell from their documentation. The only other parameter is the f0 center frequency. The shapes of the shelving filters are essentially designed to be the same, irrespective of the chosen attenuation. Hence, as per the example that I provided earlier, f0 = 180 Hz should work for all shelf amplitudes to closely meet the 70Hz specification. I've computed the shelf responses for –1.5, –3.0, –4.5, and –6.0 dB with f0 = 180 Hz, and the results are plotted below. If you look closely, you'll find that at 180 Hz each of the shelves is 1/2 of the specified amplitude.
View attachment 222871

Am I right?

 

[witwald]

It looks correct to me. In this case, the "Frequency" parameter is the center point of the shelf. As I showed in the plot, in order to achieve the target low shelf amplitude by 70 Hz, we need to set the center frequency to the right of (higher than) the 70 Hz. For this case, I've computed 180 Hz as being a reasonable setting for "Frequency".