Are AUM's built in EQs Linear Phase?

thenonanonymous

Title says it all. AUM help manual doesn't say. Anyone know?

McD

OK... I had to Google for context:

There are two broad EQ types: non-linear and linear-phase. 

Each has advantages and disadvantages.The key takeaway is that linear-phase equalization is more precise, but it tends to have less character then traditional EQ. Linear-phase equalization isn’t as common, but it can offer significant advantages in some situations so it’s worth investigating what it can do.

One potentially significant difference is CPU load. Linear-phase equalizers tend to draw more power than non-linear EQs. However, the CPU requirements vary—for example, the FabFilter Pro Q 2 equalizer has a variation on linear-phase operation that draws less CPU power than traditional linear-phase types. Linear-phase operation may also be offered at different degrees of precision (low, medium, high), with more precision drawing greater CPU power (Fig. 1). Some EQ processors offer a draft mode, which uses less CPU power, and can change to maximum precision when mixing.

Hmm... My money is on non-linear for reduced CPU load given AUM's focus on managing CPU intelligently.. This sounds like one of those A/B sound tests where I can't tell the difference without knowing the answer.

thenonanonymous

so the reason I’m looking into this is for creating a crossover in AUM... to create a simple multiband compressor

I did a bit of research which suggested using a linear-phase filter for the crossover to minimize “artifacts”

I’m just in the research stage here... haven’t done any listening tests

rs2000

@thenonanonymous said:
so the reason I’m looking into this is for creating a crossover in AUM... to create a simple multiband compressor

I did a bit of research which suggested using a linear-phase filter for the crossover to minimize “artifacts”

I’m just in the research stage here... haven’t done any listening tests

Don't worry. Just use them and add phase invertors or more EQs if you don't like the sound.

cian

I'd be very surprised if they were. I think there is an EQ on IOS that is linear phase though.

cian

Yeah, I think the toneboosters EQ has a linear phase mode.

cian

Also the fabfilter eq definitely offers this as well. Though a pricey option

thenonanonymous

@rs2000 said:
Don't worry. Just use them and add phase invertors or more EQs if you don't like the sound.

@cian said:
Also the fabfilter eq definitely offers this as well. Though a pricey option

Great, thanks for suggestions/resources... I’ll look into it.

McD

@thenonanonymous said:
so the reason I’m looking into this is for creating a crossover in AUM... to create a simple multiband compressor

Good idea. I had a similar thought recently when reading a thread about Multi-band compressors. It occurred to me I could send and input to multiple AUM channels and
EQ to isolate a band and then compress on each channel for that band. I didn't try it.
My brain always things of complexity as "adding noise" or latency so I tend to trust black boxes with good reviews but you can do a lot of "black box" magic with AUM and it's toolbox
of basic audio FX.

Someone should set this up just using AUM and share the generic project file. Tweak the volume sliders and EQ/Compressor knobs and dial in a sound and share that project file too.

Keep going and report back on the results.

animalelder

I’ve thought about this before. Something like Gaffel on iOS would be nice.

https://klevgrand.se/products/gaffel

rs2000

There are many ways to do multi-band compression.
Tried Klevgrand PressIt and FAC Bandit? These are the easiest/fastest to use.

Of course you can also split into frequency bands and saturate and/or limit using only AUM's audio processing blocks and audio busses, I suppose that each will sound different but all will do the job.

If you need big-time control, you can add FAC Envolver and route the envelope control signal to any of the compressor/limiter parameters inside AUM and fine-tune to perfection.

Processaurus

The type and quality of filters used to make a crossover pair ends up having a noticeable change on the sound, in multiband processing, like MB compression. Often because the sound will have important information at the frequency of the transition.

If you don’t have the option of linear phase, just a sharp cutoff (like 24dB/octave), and play with the frequency to try to split the bands up in a way that divides the sound up logically into elements. Thump, tone, articulation, as one example. With MB compressors I end up soloing the bands to find a good spot for the crossover, and spectrum analyzer is helpful to see where the activity is. The sound is the most compromised by the crossover where the sound is 50/50, so best to hide it between elements of the sound that don’t have resonances or notes happening, and to make width of that area narrow.

rs2000

@Processaurus said:
The type and quality of filters used to make a crossover pair ends up having a noticeable change on the sound, in multiband processing, like MB compression. Often because the sound will have important information at the frequency of the transition.

If you don’t have the option of linear phase, just a sharp cutoff (like 24dB/octave), and play with the frequency to try to split the bands up in a way that divides the sound up logically into elements. Thump, tone, articulation, as one example. With MB compressors I end up soloing the bands to find a good spot for the crossover, and spectrum analyzer is helpful to see where the activity is. The sound is the most compromised by the crossover where the sound is 50/50, so best to hide it between elements of the sound that don’t have resonances or notes happening, and to make width of that area narrow.

The advantage of doing this natively in AUM is that you'll have full control over phase, frequency band overlap and being able to process the bands differently. You may want limiting in the bass range, 3:1 compression in the mids but only little compression or rather valve saturation the high band, for example.

thenonanonymous

@animalelder said:
Something like Gaffel on iOS would be nice.

That's an interesting one... a dedicated band splitter...

@rs2000 said:
Tried Klevgrand PressIt and FAC Bandit? These are the easiest/fastest to use.

I have PressIt... and like it but it's only iPad... I'm looking for a universal app (to run on iPhone as well)

I also have the "Multi Band Visual Compressor" from 4Pockets... which I like for the visual aspects, but the problem for me here is basically that it's overkill...too much processing for my application (which I'm still just considering, and not set on) for real-time guitar. I'm focusing on sound quality and I'm looking for minimal messing with the source audio (for example, I probably only need 2 bands). Using the 4Pockets app, I tried using all bands on "bypass"... but even so, the audio spectrum is very audibly changed. Just for reference, I'll try PressIt in this context just to see if it's any better.

I hadn't heard of FAC Bandit before, I'll look into it...

I do like the idea of AUM for full customization... and minimal processing (2 bands only)... but to be honest I'm still trying to find a way to go without multiband altogether... to keep things as simple as possible

rs2000

@thenonanonymous said:
I do like the idea of AUM for full customization... and minimal processing (2 bands only)... but to be honest I'm still trying to find a way to go without multiband altogether... to keep things as simple as possible

Sure, multiband is not necessarily better for compression.