2.1 output channel for bass management of stereo mix

[amathie]

I want to try using a subwoofer to extend the low frequency range of my main stereo monitors.

For various reasons I want to do the bass management in software prior to leaving Pro Tools so that I send the resultant three channels out to LEFT, RIGHT and SUB monitors.

Voxengo produce a Bass Management plugin for extracting low frequencies from the main stereo monitors and sending them to an "LFE" channel but this requires a 2.1 bus.

The Voxengo plugin needs to be inserted on a 2.1 channel but I don't have the option of creating a default 2.1 bus in Pro Tools.

Could someone please offer a simple and elegant way of doing this.

Thanks very much.

[Darryl Ramm]

If Voxengo BMS requires 2.1 support then you would need to upgrade to Pro Tools ultimate to support multi-channel sound. I’ve never seen or used it myself.

But why oh why do you want to do subwoofer management in Pro Tools? Do you have to deliver a subwoofer track to a client? If you are working in stereo the normal place to support subwoofers is in a monitor controller or the subwoofers themselves that give you low pass etc. filter settings… a whole ecosystem of products designed to work this way.

[albee1952]

Indeed, unless your final mixes are going to only be played on 2.1 setups(very unlikely), this will more than likely lead to lots of hair pulling and remixes. I'm all for adding a sub if its called for, but it needs to be well-thought out and well-implemented. Just hooking it up and feeding it a separate output(regardless of what plugin is involved) is not going to be either. I would consider these steps:
#1-use audio analysis to determine if a sub is needed(this could be IK's ARC3, Sonarworks or a dedicated analysis tool such as SMAART or SpectrFoo, with a proper measurement microphone)
#2-if a sub will actually be useful, start by running the main L/R signal to the sub, and then the sub's hi-pass outputs would feed your main speakers. Then, do as in #1 and measure to tweak and verify you have the response desired. This might be okay if the sub is the same brand as your main speakers.
#3-an alternative connection scheme would be to use a monitor controller(such as Presonus Central Station or Audient Nero) to feed the sub separately, and add a digital crossover to properly tune the sub to your room and main speakers(the built-in crossover on most subs is completely inadequate in most cases). #3 would be my choice The Behringer UltraDrive Pro would be a solid option fortuning and tweaking(I used this in my former studio's 19' x 15' control room with twin Presonus T10 subs and Genelec 8050 mains and I miss that rig every time I do a mix now

[amathie]

Darryl and Albee,

Thanks for your suggestions and apologies for no explaining myself fully. The reason I want to do bass management in Pro Tools is because I'm trying to set up both a 2.1 and a 5.1 system (with different stereo and surround satellites but sharing the same sub). Being able to sort out the routing in Pro Tools might also enable me to fine tune these two monitoring systems with multichannel room correction from Dirac.
Ideally I would like an external Trinnov hardware system but I can't justify the price of that!

Anyway, coming back to my core problem... I've worked out that although PT Ultimate doesn't have a option for a 2.1 buss, I can just use a L-C-R three channel bus and allocate the streams accordingly via Setup I/O.

One thing I'm stuck on: If I have a aux channel with three streams, say L-C-R, is there some way of simply bussing the C stream only to a downstream mono bus that might, for example feed a sub. I can send the whole L-C-R to a mono bus but then I get all three streams mixed down to mono rather than just the C stream?

[JFreak]

Think simpler, no reason to make it so hard.

First create stereo mix aux, route its output to stereo master fader and outputs. Then set up mono master fader and output, and set up a send from your mix aux to mono master.

Now you have stereo satellites on stereo master fader and sub on mono master fader. All you need to do is setup your crossover and whatnot on master faders to control your 2.1