Low Latency Mode Dramatically Decreasing Gain of an Audio Track Even when None of The Plugins are Being Disabled

Hi

I'm aware that engaging low latency mode could result in an audio track becoming quiter if LLM disables a plugin that was providing extra gain to the signal. However, in my case, none of the plugins on my channel strip are getting disabled when I engage LLM but the audible gain of the track drops by about 10 dB. What could be the reason for this?

Here's what the channel looks like with LLM engaged. As you can see, none of the plugins in the chain are being disabled -

Also note that the pre-fader level DOES NOT decrease when LLM is engaged. It stays exactly the same but somehow the audible level of the channel decreases dramatically. This channel is routed to the mixbus that has plugins on it but again, none of those plugins are disabled when LLM is switched on.

Any ideas?

You have 3 Virtual Mix plugs going?

What is each one doing?

You have 3 Virtual Mix plugs going?

What is each one doing?

They're doing a variety of things but that's definitely not the issue because I removed all the plugins and even with no plugins on the channel the problem is still happening. And it's only affecting this track. It seems to be a mystery!

Do you have automation going on that track?

I do but just on the logic gain plugin

can you share the project with the offending channel strips? you can delete the audio

Thanks for the replies. I’ve discovered some new info. Session is attached. Note that in this session the mixbus is an auxiliary track routed to bus 2. Bus 2 is routed to the Stereo Out track.

Firstly, the bass track I’ve been trying to record on is not the problem. The plugins on that track were never being affected by LLM. It’s actually the plugins on my mix bus that are being affected by LLM.

Furthermore, the reason I didn’t previously realise that the mix bus plugins were being affected because when I switched on LLM, the plugins were NOT being disabled. They remained switched on and in the channel strip view they remained lit up in blue, not in grey with orange text as you would usually expect with a disabled plugin in LLM. However, when LLM is on the plugins were behaving as if they were receiving no input signal. So they were switched on and active in the channel strip view but they looked as if there was no audio on the track. So this isn't a case of LLM disabling the plugins as it usually does.

The mixbus track fader also shows that the track isn’t receiving any audio when LLM is on. However, the Stereo Out track is. This seems impossible.

So now I’m thinking two things.

1. Why would the mixbus track not receive audio from the the bass track when LLM is on?

2. If the mixbus track is not receiving audio, how could the stereo out track be receiving audio from the bass track if the routing goes Bass > mix bus > stereo out?

Then I decided to ignore thought 2 momentarily and just focus on thought 1. If the mix bus isn’t receiving any audio, obviously that would explain why the plugins wouldn’t have any input signal. But it gets even more confusing now:

I decided to take the plugins from the mix bus and put them on the Stereo Out track and route the bass track directly to the Stereo Out track. Now the mix bus track is out of the equation entirely. The result was the same - the plugins on the stereo out track are on and active but are receiving no signal. However the stereo out track fader does in fact show signal whereas the mixbus track didn’t.

So now I know that this isn’t just a case of the plugins not receiving audio due to the mixbus track somehow being bypassed. Even with the mixbus track deleted and with those plugins placed on the Stereo Out track, the plugins are still not receiving audio when LLM is on but the Stereo Out track IS receiving audio and the plugins ARE enabled.

So first of all, what the hell is that about? Why would the plugins not receive audio when LLM is on?

And secondly, If the mixbus track is not receiving audio, how could the stereo out track be receiving audio from the bass track if the routing goes Bass > mix bus > stereo out?

Thanks

session test 2.zip

If mix buses contain latency inducing plugins, the audio will be rerouted directly to stereo out, so the effects on the bus will not be displayed as "orange" because none of the processing goes through them anyway.

consequently, any gain changes happening on the mixbus will also be bypassed.

it's a bit confusing because Logic makes no obvious indication that it's rerouting things on the fly, but i hope it clears it up.

the buses are painted orange if theyre on the "sends", but not if they're used as direct outs.

it works the same way tho. so if you have NO OUTPUT on the track, and you send it to a bus with latency, LLM will paint the bus orange and route the track directly to stereo out through the send. (which is weird but anyway)

If mix buses contain latency inducing plugins, the audio will be rerouted directly to stereo out, so the effects on the bus will not be displayed as "orange" because none of the processing goes through them anyway.

consequently, any gain changes happening on the mixbus will also be bypassed.

 

it's a bit confusing because Logic makes no obvious indication that it's rerouting things on the fly, but i hope it clears it up.

Thanks for that.

When you say “mix buses”, to be technically specific do you really mean any auxiliary track that is being used as a bus at any stage in a session? In other words, not just “the mixbus” (which is a term most commonly is used to refer to the final bus, the “2 bus”, the “stereo bus” etc).

Continuing on…..so what you’ve said explains why the plugins aren’t receiving audio - LLM bypasses the mix bus and sends the audio that was going to the mixbus directly to the stereo out. Therefore it makes sense that the plugins wouldn’t be receiving audio. And because they are not receiving audio, there’s no need for logic to colour them orange. However, that doesn’t explain why the same plugins are also acting like they are receiving no audio even when they are put on the Stereo Out track and the mixbus is deleted. The Stereo Out is definitely receiving the audio (the track fader is showing it) but the plugins aren’t. What’s up with that?

yeah i meant any auxillary track fed by a bus

Also, it seems that logic bypasses Stereo Out plugs without turning them orange as well.

yeah i meant any auxillary track fed by a bus

 

Also, it seems that logic bypasses Stereo Out plugs without turning them orange as well.

Ok. Thanks. This is pretty weird as I had already recorded on a duplicate of that bass track twice with LLM engaged and this wasn't happening. It just started happening all of a sudden.

Also, when I turn LLM on, the bass drops considerably in volume but all the other tracks sound exactly the same. When I look at the plugins on the mixbus, they are receiving audio but when I solo the bass track they are not and the mixbus aux track is bypassed. So when LLM is on, does Logic skip the bus and send the audio directly to the stereo out but only for the track that is record-enabled and/or input monitored?

Hm, i will have to check. But logic only does that for plugins that have latency! Have you checked how much latency each plug has?

I'm not exactly sure how to do that.

It does seem pretty extreme that ALL of the mixbus plugins are being skipped now

Slate VMR

Oxford Inflator

Pro Q 2

Waves SSL Compressor

Ozone 8 Dynamics

Slate Virtual Tape Machine

Fielding Reviver

Pro-L 2

It's seems weird that they are all being skipped especially as this wasn't happening when I recorded before. All of a sudden they are all skipped.

Name 0,3ms (24 samples)

Hover above the plugin with the mouse, if it has no latency the tooltip will only show the name, else it will be something like:

Name 0,3ms (24 samples)

They all only say the name and either "untitled" or "default setting" except for the following:

Ozone Dynamics 395 samples = 9 ms

Slate Virtual Tape Machine 1728 samples = 39.2 ms

Reviver 76 samples = 1.8 ms

Pro-L 2 2875 samples = 65.2 ms

Can this info help me in solving the issue?

I haven't read this entire topic, but have you tried simply disabling the suspected plugins to see if that alters the gain in the same manner, and so pinpoint the plugin(s) responsible?

You could also simply insert Gain plugins on whichever tracks are dropping, and compensate for the gain drops by engaging those, and bypassing them again when you are out of Low Latency mode.

However, many have the workflow that they do not start the mixing phase before the tracking phase is done. When tracking, I do some mixing, but only with low latency plugins. It is completely possible to get a decent ("loud") mix without using any high latency plugins. Gain staging is the magic word here.

I haven't read this entire topic, but have you tried simply disabling the suspected plugins to see if that alters the gain in the same manner, and so pinpoint the plugin(s) responsible?

You could also simply insert Gain plugins on whichever tracks are dropping, and compensate for the gain drops by engaging those, and bypassing them again when you are out of Low Latency mode.

However, many have the workflow that they do not start the mixing phase before the tracking phase is done. When tracking, I do some mixing, but only with low latency plugins. It is completely possible to get a decent ("loud") mix without using any high latency plugins. Gain staging is the magic word here.

Thanks for that. It's a little more complicated than that unfortunately. The first post actually doesn't describe the issue totally correctly.

What I'm going to do for now is route the audio track I'm trying to record on directly to the Stereo Out and then turn down the mix bus aux track while I'm recording.