Those mysterious Liquid Mix settings

[David Polich]

This is a question for anyone using Liquid Mix with DP.

I'm trying to find the "set it and forget it" hardware setup settings for Liquid Mix. Focusrite's "math formula" for setting buffers and setting the Liquid Mix software is too confusing.

Yesterday I opened a project with four stereo tracks, seven mono tracks, two instances of Wizooverb, one instance of Waves Linear MB, two instances of Channel Strip, and three Waves 4-band para EQ's. I tried running just one instance of Liquid Mix, on the lead vocal, and I was getting serious popping and CPU spikes, processor up to 60%. A second instance of LM drove the CPU to 90% and double the popping. I had to take the two LM instances out and finish the mix with other plugs.

Another project with twice as many tracks and plug-ins caused me no problems with Liquid Mix at all. I could set up as many LM's as I wanted.

Buffer settings in DP 4.61 are - 512, multiplier 1, work priority high. LM setup is 44.1khz, 24 tracks, minimum latency 520. This has been working fine until yesterday. I tried setting the buffers to 1024, multiplier 2, it didn't fix anything. I wish Focusrite would put up a chart saying, in effect, if your hardware settings are "x", then the LM setup should be "y" - something simple.

I wonder if it's the particular project - has anyone ever had certain projects that mysteriously gobble more CPU than others?

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G5 PPC Dual 2.3Ghz, 4.5 GB RAM, 828 MK II, MIDI Timepiece AV, DP 4.61, OSX 10.4.9, second inernal drive for audio.

[chucks]

If I remember correctly, Focusrite recommends the LM be set at 2x the host buffer rate + 8. So if DP is set for 512, you set the LM for 1032. It's on their site somewhere and this formula is working fine for me. I had problems with the LM set at lower buffers also.

[jaygro]

Here is what I have been doing... Leaving the LM at 520... my DP buffer is never lower than 256 when mixing.

This is from the LM 2.0 update PDF

VARIABLE LATENCY
Liquid Mix latency is now variable. It depends upon two factors: DAW buffer size and the Liquid Mix Minimum
latency setting, selected within Liquid Mix Manager (described below). You can check the Liquid Mix plug-in
latency at any time while the plug-in is open by clicking the Liquid Mix logo in the top left corner of the plug-
in window. This displays the current sample delay of Liquid Mix plug-ins on your system.

MINIMUM LATENCY SETTING
Within the Liquid Mix Manager window is a new option called Minimum Latency, with 6 possible settings
ranging from 264 to 8200 samples.
The Liquid Mix latency is tied to the DAW buffer size in the following way:
LM Latency = 2 x Daw buffer size + 8 samples
For example, if the DAW buffer size is set to 256 samples, the resulting Liquid Mix plug-in latency will be 520
samples (2 x 256 + . This rule is true so long as the result is greater than or equal to the Minimum Latency
set in the Liquid Mix Manager. In other words, the Liquid Mix latency is tied to the DAW latency down to a set
minimum. For example, if the DAW buffer size is set to 128 samples and the Liquid Mix Minimum Latency is
set to 520 samples, the resulting latency will be 520 samples. However, if the DAW buffer size is set to 256
samples and the Liquid Mix Minimum Latency is set to 264 samples, the resulting latency will be 520
samples. Remember, if this all sounds too confusing, just check the latency in the plug-in window as
described above!

In summary, the Liquid Mix latency is defined by the Minimum Latency setting made in the Liquid Mix
Manager, UNLESS the DAW buffer size multiplied by 2 plus 8 samples is over that value. If you are
experiencing performanceproblems with Liquid Mix then setting the Minimum Latency value higher will
normally alleviate any issues with the CPU.


So I take that as you need to set a minimum buffer in LM... as long as the DAW buffer is equal to or over you are OK.


Also, make sure all are set to run in real time then open hardware setup then just cancel or ok out of it. I always load all the LM I am going to use then open the hardware setup. Just seems like MAS needs to reboot sometimes.

Hope this helps.

jay

[David Polich]

If I remember correctly, Focusrite recommends the LM be set at 2x the host buffer rate + 8. So if DP is set for 512, you set the LM for 1032. It's on their site somewhere and this formula is working fine for me. I had problems with the LM set at lower buffers also.

Thanks guys. That's the kind of "formula" I was trying to figure out.