Stereo Tool

Afaik, it's very hard to make such hpf. Creating hpf is much harder then lpf.
Also twice harder then that is to make to be phase linear.

That's why I mentioned the notch filter. A notch filter would have other uses, such as notching out 50 Hz or 60 Hz (electrical hum), or some rumble in a mix.

Yes, this is a high-end / DJ / mixing / mastering discussion, not just for general home use. I'm a general home user, but I did have aspirations of something more 20 years ago, and given the total silence from applying for IT jobs, I may need to look at other career options.

I think a notch filter with those characteristics is even harder to create.

Well, without some sort of change, the region from 20-40 is very difficult to control.

Another idea:

Bass Boost - change the maximum boost from 0 to xxx to be from [highPassFrequency] to xxx

Brian,

The whole problem is that this region is indeed very difficult to control - unless I add a large amount of latency. If I double the latency, I can also double the precision. The other option to make the filter steeper is by loosing phase linearity.

(There are more options; the current implementation of some of the filters is not correct according to signal processing theory. And that has the most impact on very low frequencies. The problem is that fixing it will increase the CPU load - by at least a factor 2, maybe even 4).

I could also make the non-phase linear highpass filter steeper, but people were earlier already complaining about artifacts that were caused by that (where the steep drop starts, you hear strange things). Moving it closer to the end (after AGC and Multiband, just before the final clippers) is also an option, but that would double the latency (not sure if that's a bad thing, as long as it's a conscious choice).

Hans

In STS "Maximum boost from 0 upto" is called "Start lowpass frequency of input filter" and IMO that should match exactly one of the (linear) center frequencies in Multiband (and that is not the case for most presets).
Bass Boost and its limitations in the GUI to plain +/- 10 Hz steps is often one reason for instability in Multiband or a muddy sound.
Modify your presets in STS to match exactly one of your bass center frequencies for the Multiband and you will hear significant improvements !

What is the reason that "Then dropping to no boost" in the GUI is fixed to have at least a minimal difference of +100 Hz to "Maximum boost from 0 upto" ?

For example I have edited STS files to have 60-120 instead of 60-160 forced in the GUI and that sounds much better (punchier and less muddy).
Also an edited STS with 120-120 (I guess in theory that introduces artifacts ?) sounds practically much better than 120-220 forced in the BB GUI.

Is that x2 or x4 total load, or x2 or x4 of the load of the individual filter(s) in question (thus being something potentially significantly less than x2 of the total)?
And what about a band-stop (aka notch)?