More and more material needs to be delivered in surround formats, but what if you don’t have the time or the budget for a 5.1 remix? I took a look at the current crop of ‘unwrap’ plug-ins that can create a surround master from a stereo mix.
The best way of creating a surround master is to mix, or remix, from the source multitrack session into surround. However, this isn’t always possible, either because the source material is not available, or time and budget don’t permit. This is where ‘unwrap’ plug-ins can come to the rescue. In this feature, we are going to take a look at the ‘unwrap’ plug-ins currently available for Pro Tools, try them out on a range of different test material, and see what they can and can’t do. As you’d expect, all of these plug-ins require an system capable of working in surround to run.
The Art Of Unwrapping
When undertaking unwrapping, there are a few things you need to consider: whether you want the process to be purely additive (in other words, creating new content for the Rear and Centre channels but leaving the main L and R speakers untouched), whether the ability to collapse to stereo again is important, and whether an LFE channel should be derived or not. All of these requirements will affect what processes you can apply to your source material without experiencing any unpleasant side-effects, and there are also some general rules that should be followed where possible:
Try to put the ‘unwrap’ plug-in as the last plug-in in the chain on a track. This will be the most DSP-efficient way of working, as it means that all your other plug-ins will be processing either mono or stereo audio rather than five or six channel audio.
Do not rely on being able to create precise sound images placed between speakers at the side of the listener for stationary sounds. Our ears are very poor at localising sound to the side, so while movement in sounds through the sides is fine, reliable placement of sounds between, say, the Left Front and Left Rear speakers is impossible.
Heavy use and manipulation of the Centre channel can hinder the accurate folding down of the mix to stereo. If proper fold-down is important, make subtle use of any Centre channel processing, and always check your mix for compatibility.
The same goes for the Surround (Rear) outputs: the more processing you employ, the more any subsequent ‘downmix’ will be compromised.
Whenever you are mixing in surround, in whatever format, downmix considerations should be always in your mind. You cannot predict how your surround mix is going to be listened to further on down the chain. Where possible, it is best practice to include a properly remixed stereo version of any surround content. The DVD-V and DVD-A formats both allow for this. However, it isn’t always possible or doesn’t always happen, so you have to consider that some listeners will hear your surround mix in stereo or even in mono derived from a downmix, created in their equipment, of your surround mix. So when mixing or upmixing in surround, you need to regularly check how your surround mix sounds when it is downmixed again.
Waves 360 Surround Imager
Until now, this was the plug-in I used to unwrap stereo material in a surround mixing environment in Pro Tools, and I have been very satisfied with the results. However, this plug-in was definitely the least effective of the ones tested here — although it could be argued that it is a clever surround pan pot, and so it is possibly being pushed beyond its intended use here.
Price not available on its own (part of the 360 Bundle $1200 Native)
In general this plug-in works fine but more my taste a lot of the presets provide a coloured sound especially when compared with the others. For music this coloration is less of a problem but for sound effects and dialog it wouldn’t be my first choice.
Price $200 Native (also part of the 360 Bundle)
TC Electronic Unwrap
This plug-in handled all the samples very well, and has a good selection of presets. The good news for anyone who already has a System 6000 with Unwrap presets saved is that you can import them into the Pro Tools plug-in too. This plug-in always could be set up to be faithful to the original sound and then, if desired, set to enhance it too. This plug-in comes top of the class, but for me, the surprising thing was that it only just made it.
Price $1,099 TDM only
It just worked, no frills, the mono dialog was routed to the centre speaker but you do have the option to spill it into the front left & right speakers with the Divergence control. Also you can open out the front image width with a Width control. Only the ambience went to the surround channel, with only just a hint of the front dialog finding its way into the rear channels. There was no sound of any ‘processing’, which you can get with this kind of plug-in.
TC Electronics Unwrap is the best but it is also the most expensive. The best value for money is the Soundfield UPM-1