Ableton Forum

I have been using an Audio Effect Rack with three chains for Low, Mid, and High, so that I can set the lows to mono and widen the mids and highs if needed.

However, I find that using EQ8 for this colors the sound noticeably. I've seen in several tutorials that others use Multiband Dynamics with a single band soloed per chain, instead of using EQ8.

I just set up my own Audio Effect Rack with Multiband Dynamics. However, I am hearing a noticeable unwanted coloring of the sound, similar to what I got when using EQ8 to split the bands.

It sounds as if the frequency at which the mid-high bands are split is emphasized. For example, with low/mid set at 120Hz and mid/high set at 2500Hz, I can hear an upper-mid boost that sounds like it's around... well, 2500Hz. If I use Spectrum, it seems that the highs are boosted by a few dB. If I sweep the mid/high frequency, I hear what sounds like sweeping a notch filter. If I move the mid/high crossover frequency all the way up to 15kHz, the sound seems to be the same as if the Audio Effect Rack were turned off.

How do I get a frequency splitter without getting this unwanted notch and high boost? I merely want to have control over the width of three or four bands per channel, and these unwanted EQ changes are driving me mad.

contortrix wrote: I find that using EQ8 for this colors the sound noticeably

With EQ8 in oversampling mode?

In my experience EQ8s and Multi Dynamics devices in a rack will always colour the sound with boosts or notches at the crossovers, even when using a Utility device with the phase flipped on every other chain. It's great for adding different fx per band/chain, but i don't think you'll ever get it 'clean'.

have you tried any 3rd party vsts? Fabfilter Pro-MB has width control per band.

garyboozy wrote:
have you tried any 3rd party vsts? Fabfilter Pro-MB has width control per band.

The type — minimum phase, 1st or 3rd order Butterworth filters, or Linear phase — and quality of the filter seem to be a determinant factor. High quality minimum phase filters is where I'd look first. I'd assume Fabfilter belongs there but I have never tested for this purpose.

This ended up being a good excuse to break down and try out Pro-Q. It was on my "list of things I should really buy at some point when I have the time and a specific need". With blind A/B testing, I can't hear any coloring when using Pro-Q to split the bands. Only issue is that the macro knobs now show 0-127 instead of Hz, but I can live with that. I've not tried switching from zero-latency to linear phase yet, but the default zero-latency setting is transparent to my ears. RIP my wallet, but this appears to be the solution.

Do a null test. I first did it wrong and thought it summed to zero but no it's very colored.

With EQ8 and Utility (to invert the phase)you can easily create a 100% transparent multiband splitter.
I'm pretty sure you can even find some downloadable racks on the net.

@jur Yes - and the issue coming up in this forum is that there are all sorts of bad racks and bad info. For anyone still on this - we want to make an actual x-over and you can null test that. Here is such a premade rack jur mentions
https://elphnt.io/store/splttr/

And another Ableton forum talking on the same topic has some good dialogue
viewtopic.php?t=201124

namely this comment and response

Vios wrote:
One thing to note is that a frequency crossover is never transparent. In the analog world, a capacitor or inductor that make up a crossover cause phase shift starting about an octave above the crossover point. In the digital world, the algorithms that cause a separation of the frequencies have a similar effect. Try putting an EQ3 after a limiter and you'll immediately see what I mean - it probably won't sound much or any different, but you'll see your signal spiking above the limiting point of the limiter.

Not completely true. You are correct that the filtering creates phase shifts, but they can easily be reversed/compensated for. This crossover divider is completely transparent & is actually based on an analog technique. Speaker crossovers often use this method. It's a really simple concept, You use a Low pass (or highpass) to create a signal band. In this case a low pass, & you end up with a "low" filtered band. You then mix a polarity flipped mult (copy) of that signal with original source. This cancels out Low information & gives you the "High" band. Thats it, repeat the process for as many bands as you need.
Most multiband processing will use a irr or fir filtering method, they have advantages for steep filtering, but in a mastering situation or any situation you want 100% transparency my example is the way to go.

@djspirit Audio transparency = A signal not being modified in any way. You might enjoy polarity null testing signals to learn what processors change. Just send the output of the signal in question to a bus, & send the original unmodified signal to the same bus but reverse the polarity before hand. With live use the utility tool for this task. This will show you the differences of the two signals. (I stopped using Live after ver 7/8 so I'm not sure if they have added a polarity flop to the mixer or not. If so you can use that over the utility tool)