Finding bandwidth over center frequency? (param eq)

[DJ Higgumz]

I am running a behringer 8024 ultracurve, and I want to set a highpass and lowpass for my new t60s. my variables are center frequency and bandwidth per octave which adjusts by 1/60th octave. The fixed value is a f2 (high end freq) of 25 hz. The gain would be somewhere around -24db, doesn't have to be accurate.

I hope someone can help me out or find a calculator on it I couldn't find nothing. If anything help my find the bandwidth per octave of 15-25 hz that would help

[DJ Higgumz]

Wait I think I figured it out in my head

So an octave is a doubling of frequency so
20-40= 1 octave
So in this case the one octave is 20 hz, 40-20=20.
F2 is 25, which in the 20-40 hz spectrum it would be 5.
So then 5/20= .25 of the spectrum
and since my eq works in intervals of 1/60th octave I would do .25x60=15

So the result would be 15/60 bandwidth, center frequency 20hz.

I hope this equation translates with you!

Yet another edit, anything under 20hz would be back to zero, tomorrow I'll sketch an equation taking that in account, but it is 130 am, I'm tired haha

[Radian]

I am running a behringer 8024 ultracurve, and I want to set a highpass and lowpass for my new t60s.

Wrong tool for crossover duty.

[Bill Fitzmaurice]

I am running a behringer 8024 ultracurve, and I want to set a highpass and lowpass for my new t60s.

Wrong tool for crossover duty.

+1.

[DJ Higgumz]

Could you explain?

[Bill Fitzmaurice]

Could you explain?

It's not a crossover, simple as that. The filters lack sufficient slope and depth. Get the right tool for the job.

[Radian]

The 8024 is an Equalizer. To accomplish what you intend to do, you need a Crossover.

*edit* "Yoda" beat me to it.

[DJ Higgumz]

so i have a mackie m1400i amp with a high pass on it, but it is just a pan pot, so it isn't precise. what I wanted to do was start the slope with the behringer, then the amp's highpass would take over the majority of it. i just don't want the rough estimate on the amp. the amp also has a fixed xover at 125 hz, which I have on, but eq on the behringer down to make it 100 or lower. not the ideal setup but it's the cards i'm dealt with, when more funds come in i'll look into a deq2486 or whatever it is

[Radian]

You can set the variable HPF accurately using a test tone, multimeter, and the Voltage / dB formula. That or leave it at the 9 o'clock position. For the low pass, flip the switch over to 63 Hz instead of 125.

That's about the best you can do until you get the right tool like a DCX, Super-X, DriveRack etc etc....

[DJ Higgumz]

the problem is my tops will never reach that low, they barely hit 100. if the max attenuation is 16 db on the eq, and a standard xover is 24db/ octave, an octave from 100 is 200 hz, so that would be far steeper if i go straight to -16 db. then the 125hz will take it farther from there, giving it the depth. couldn't that work?

[Radian]

the problem is my tops will never reach that low, they barely hit 100. if the max attenuation is 16 db on the eq, and a standard xover is 24db/ octave, an octave from 100 is 200 hz, so that would be far steeper if i go straight to -16 db. then the 125hz will take it farther from there, giving it the depth. couldn't that work?

You have to look at what the response is doing, not just going strictly by where the set point is. 24 dB/oct is an awfully steep slope, especially in combination with a cab's natural roll-off.

[DJ Higgumz]

yeah i understand that, everything inbetween is adjustable.