Example of filter with 6db/octave

I want to implement a high pass filter with 6db/octave. As far I know, JUCE filters are 12db/octave by default. Can anybody help to figure out this? my code currently looks like this.

header:

juce::dsp::ProcessorDuplicator<juce::dsp::IIR::Filter< **float** >, juce::dsp::IIR::Coefficients< **float** >> filter1;

cpp:

*filter1.state = *juce::dsp::IIR::Coefficients< **float** >::makeHighPass(mSampleRate, 20, 0.7);

**auto** audioBlock = juce::dsp::AudioBlock< **float** > (buffer);
**auto** context = juce::dsp::ProcessContextReplacing< **float** > (audioBlock);

filter1.process(context);

Thanks in advance.

You can use makeFirstOrderHighPass which should be -6dB/octave.