the `dsp::FilterDesign::designIIRHighpassHighOrderButterworthMethod`

functions let us compute the coefficients for a highpass filter with a slope that is a multiple of 6db/oct (the `order`

).

However, they don’t let us adjust the Q. Instead, the Q is computed for us automatically based on the filter order we supply.

I’m trying to replicate the Q control in Logic Pro X’s channel EQ.

I know I need to directly call `IIR::Coefficients::makeHighPass()`

or `makeFirstOrderHighPass`

for each link in my ProcessChain required for the slope I need, but I don’t know what to supply for the Q parameter to these functions.

the helper function that produces the array of coefficients computes the Q via this if the order is a multiple of 12db/oct:

```
auto Q = 1.0 / (2.0 * std::cos ((2.0 * i + 1.0) * MathConstants<double>::pi / (order * 2.0)));
```

or this, if the order is not:

```
auto Q = 1.0 / (2.0 * std::cos ((i + 1.0) * MathConstants<double>::pi / order));
```

Can anyone shed some insight on how the `0.10`

and `100`

work as a Q parameter in the Logic Pro X channel EQ?

How would that same computation be used as the `IIR::Coefficients::makeHighPass()`

`Q`

param?