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skyhigh wrote:when would it be a good idea to split frequencies?

There are two reasons why one might split the frequencies of a signal.

1> To maintain control of the signal.

2> For creative purposes.

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If we split the signal for control purposes, we are most likely looking at multiband compression. Low frequencies trigger compressors before higher frequencies (although I actually don't know why )...

By splitting compression into multiple frequency ranges (bands), we can process bass with more precision than single band compression. This will give a clearer mix, since using frequency dependant compression can allow for the 'loudest' frequncies to be attenuated (turned down) whilst other frequency ranges are unaltered and thus true to what was orignally intended.

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Frequency splitting for creative purposes follows the same principal as using frequency splitting for control purposes. It gives greater control over what happens to both the signal and the overall mix.

Applying effects to separate frequency ranges allows for more precise control. As an example, we might compress the lowest frequencies, whilst adding chorussing to the midrange, and saturation to the highs. Doing so would give a signal that was present, yet mixable. The lows wouldn't overpower any higher frequencies in the mix, the midrange would sound 'interesting' whilst the highs would sound 'present'.

Sometimes it is interesting to add the same effect across all the frequency bands, yet with different settings for each band. Apply distortion would be a fine example of this scenario.

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Splitting is done in two ways.

1> By using filters (phase cancellation)

2> By subtracting a copy of the signal from itself.

In both cases, we would send a copy of the signal to a bus, upon which, a filter or maths unit would function to split the incoming signal into bands.

Using filters is the easiest way.

To split the signal into three bands, we would send the signal to three buses. On each bus, we would use a filter to separate the signal into bands.

-On the first bus, we would use a low shelf filter to remove all frequencies above the cutoff point. This becomes our low frequency band.
-On the second bus, we would use a band pass filter to only allow the mirange frequencies through. This becomes our midband.
-On the final bus, we would use a high shelf filter to remove all frequencies below the cutoff point. This becomes our high frequency band.

Following the filter on each band, we could add compression or effects.

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Of course, I could be chatting shite, so feel free to add your experiences of frequency splitting too!

Pat

Top post chief - 2 things

futures_untold wrote: If we split the signal for control purposes, we are most likely looking at multiband compression. Low frequencies trigger compressors before higher frequencies (although I actually don't know why )...

Low freqs tend to trigger compressors before HFs as typically they have a higher peak level (Fletcher Munson; they need to be louder to be heard as the same level).

By splitting compression into multiple frequency ranges (bands), we can process bass with more precision than single band compression. This will give a clearer mix, since using frequency dependant compression can allow for the 'loudest' frequncies to be attenuated (turned down) whilst other frequency ranges are unaltered and thus true to what was orignally intended.

Eq can do that too - without the nasty side effects Perfect-reconstruction filters are all well and good, but as soon as you start processing (the comp starts working) you have phase problems at the crossovers.

Bottom line: Splitting a signal up into bits and then treating them differently can't help but affect the integrity of your signal. Sometimes that's a price worth paying, sometimes not. Generally it's better for creative stuff or for fixing very specific problems, IMHO. MB comp changes your sound, changes your mix. Choose very very carefully if you're doing it to everything.

Aside from that, splitting basslines up and mashing them to pieces is lots of fun

busses explain more when at work 2morrow

* A variant would be to split only to 2 channels so you just keep the bass clean and mess indinstincly with all frequencies above which imho is usually enough.

* Sending all the buses to a master bus makes EQing easier.

* Insert a compressor on the low freq bus so you don't have a 6 dB amplitude on the bass.

* A guy on DOA said "the best sounds aren't made by turning one dial up to 11, but by turning eleven dials up to 1". You really want to follow this advice. You can apply a lot of effects on your bass but only a tiny bit at a time. This really makes a huge difference.

* Resample regularly.

I seem to understand much better now.

Now, here's the tricky part for me... taking all of this fresh information and making it work for me within Reason 4.

Future's Untold, I know you have a FREQ SPLITTER patch for reason, and I will definately be loading that up into my rack, but quite honestly I would love to know how to do all of this on my own.


1 New Question for Daft tnuc:

Resampling reqularly?? Unsure of what this means.


And once again, Thankyou so much for the lengthy, information-packed responses!

The basic process of resampling is as follows;

1> Make or record a noise into your sequencer (using a synth or sampler - with or without effects.)
2> Render the audio to disk, also known as 'bouncing to disk'. Usually one bounces to high quality WAV or AIFF.
3> Import the sample into your sampler.
4> Continue to process the sample with effects, or do funky edits like reversing the audio etc.

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Frequency splitting can be done simply in Reason.

Use the sends on a Mixer 14:2 to route the audio to multiple MClass Stereo Imagers. The stereo Imagers act as the cross-over filters to define the frequency range of each band.

Remember to turn up the send pots on the channel you wish to split. Also, there is no need for the mixers master output to be connected to anything unless you want the frequency split to be a send effect.

Here's a quick image of what I mean..

macc wrote:

futures_untold wrote: If we split the signal for control purposes, we are most likely looking at multiband compression. Low frequencies trigger compressors before higher frequencies (although I actually don't know why )...

Low freqs tend to trigger compressors before HFs as typically they have a higher peak level (Fletcher Munson; they need to be louder to be heard as the same level).

Thanks for clearing that up for me!

I think by using subtraction rather than filters, one can avoid phase problems... See De La Mancha Fr33some for more info on this ---> http://www.delamancha.co.uk/fr33some.htm

And plenty more discussion upon the drawbacks of each method.... ---> http://www.kvraudio.com/forum/viewtopic ... sc&start=0

For non Reason users, try Robin Schmidt frequency splitter ---> http://www.rs-met.com/software/freebies ... y_v0.6.zip

futures_untold wrote:The basic process of resampling is as follows;

1> Make or record a noise into your sequencer (using a synth or sampler - with or without effects.)
2> Render the audio to disk, also known as 'bouncing to disk'. Usually one bounces to high quality WAV or AIFF.
3> Import the sample into your sampler.
4> Continue to process the sample with effects, or do funky edits like reversing the audio etc.

----------------------------------------

Frequency splitting can be done simply in Reason.

Use the sends on a Mixer 14:2 to route the audio to multiple MClass Stereo Imagers. The stereo Imagers act as the cross-over filters to define the frequency range of each band.

Remember to turn up the send pots on the channel you wish to split. Also, there is no need for the mixers master output to be connected to anything unless you want the frequency split to be a send effect.

Here's a quick image of what I mean..

ABSOLUTELY AMAZING. Thankyou so much Futures Untold!

You could also add mid/side splitting into this melting pot. you can get amazing results with mid/side EQ on a master bus or even just to mess with the stereo field.

If you use a linear phase eq like the waves broadband lin eq to split the frequencies wouldn't you not have to worry about phase problems? or at least worry less?

In theory you're right, although I doubt any eq has perfect linear phase.

Try it and see if it sounds better to your ears.

I haven't tried the multiband compression technique, using filters does it for me.

However, I would rather use a very steep filter (8 Pole / 48 dB steep, so there's no gap between the different channels) than lo & hi shelves.
For the same reason, I also prefer combining a lp and hp on the mid channel using the same cutoff values as the low and hi channels.
As a reference, good cutoff values are 0 - 150 Hz for the bass, 150 - 1.5 kHz for the mids and 1.5 kHz - 20 kHz for the hi frequencies.
It's not the only way to do it but it's a good starting point.

Somebody who uses a linear phase eq can try and see how it deals with phase cancellation ?

I remember basic a telling me(and posting) to use multi-band compressors for eq'ing. Do you think it really makes a difference futures_untold? When splitting with regular eq's there is some sound "loss" but its not terribly noticeable.

Great thread btw! Lots of useful information.

yeah really great thread!


What do you think the advantage of using multiband compression be over using linear phase eqs?

ddeez wrote:yeah really great thread!


What do you think the advantage of using multiband compression be over using linear phase eqs?

Multiban compressors are just a convenient source of a linear phase EQ, which most DAWs have easily accessible

therook wrote:I remember basic a telling me(and posting) to use multi-band compressors for eq'ing. Do you think it really makes a difference futures_untold? When splitting with regular eq's there is some sound "loss" but its not terribly noticeable.

Great thread btw! Lots of useful information.

Dont you mis-quote me, I told you to use it too split frequencies, not for general eqing, thats silly.