ValhallaRoom EQ request

[valhallasound]

Alright Sean, thanks for that explanation. I didn't know that 3db filters were difficult even in the digital realm. I guess spectral EQ is the way to go for non-6db slopes.

A big FIR filter would do the job as well. You can dial in all sorts of frequency responses with an FIR, given enough taps. FIR filters tend to be "set and forget," with the coefficients determined at initialization time, or by selecting from a table of coefficients that are precalculated in MATLAB or the like. I don't know of many FIR filters (i.e. one where you can change the frequency/slope on the fly). Then again, I'm not an expert on digital filters. I tend to use a couple of different topologies over and over again.

Sean Costello

[LX_Nen]

I'm sure this must be wrong, but I'd be interested to know why It's wrong...

If you mix 50% of the source with 50% of a 6db/oct filtered version don't you get a 3db/oct filter? I'm guessing there are phasing issues that stop this working for most types of signal, but for noise I'd have thought this wouldn't be a problem?

[pdxindy]

I'm happy with the Valhalla verbs as they are. Adding eq myself is preferable cause I can do exactly as I want for a given circumstance. Adding eq to VRoom means it is either very simple and then will only fit some situations or it is complex and makes the plug-in complex.

When I was first using VRoom I thought I wanted eq, but now I like it better without.

[ras.s]

- Adding a full-fledged EQ to VRoom would make it a considerably more complicated plugin, where my current goal is to move in the opposite direction. I want to create plugins with as few parameters as necessary, to make things easier to use.

I like your philosophy and agree.

Just as a thought, a joystick/XY-panel as an UI element makes interfacing with a "one-knob" filter more flexible and interesting, yet still keeping simplicity. Could suit here ..

[mystran]

I'm sure this must be wrong, but I'd be interested to know why It's wrong...

If you mix 50% of the source with 50% of a 6db/oct filtered version don't you get a 3db/oct filter? I'm guessing there are phasing issues that stop this working for most types of signal, but for noise I'd have thought this wouldn't be a problem?

Nope, you don't. If you mix 50% unfiltered with 50% 6dB/oct (let's say low-pass) you get a "one-pole shelf" with high-frequency (in the case of low-pass) gain of 50% = 0.5 = -6dB. The trouble is, the "6dB/oct" refers to the "slope" at which the gain of the filter decays (specifically "far" from the cutoff) where as the summing of two signals is just your ordinary sum (well, ignoring phase, but it won't help anything here.. although I want to point out that if "noise" was immune to such "phasing issues" it would be impossible to filter noise, which clearly is not the case).

That said, the transition slope of such a shelf can be sort of reasonable approximation of 3dB/oct and some people have designed approximations of 3dB/Oct filters by cascading several such shelves (such that each provides the required slope over a finite range of frequencies). Probably the best place to start from would be http://www.firstpr.com.au/dsp/pink-noise/ which provides some reasonable low-order approximations (and also direct algorithms for generating approximate pink-noise.. "true pink noise" is more or less impossible because there's no finite bound on the levels at low-frequencies; it's no "stationary" so it can drift anywhere if you wait long enough).

[LX_Nen]

Many thanks for clearing that up for me. That link is fascinating reading (but right at the limits of the maths I can still remember from 25 years ago).

Basically, what I should have realised is that a 3db/oct filter shouldn't let much sound through at all after several octaves, but my dumb idea of mixing 50% percent of the original in always leaves at least 50% of the source.

[Unqlenol]

Sorry to Necro this thread, but I would like to add that I feel there are many situations where Room is great as an insert. Thus I agree that a high pass or low cut within the plug would be awesome.

I have been using it on my master buss at between 0.5 and 5% wet. I like the result however I wish I could roll off the bottom to keep it totally dry. Yes, I know I should set up a send, but I like the workflow with it as an insert in this fashion.

Right now I am trying to dry up the bottom by pulling down the bass multiplier big time....but its not the same thing.