much like riding the fader — simulating tucking the fader down a little bit when someone isn ’ t singing or playing in order to reduce bleed . One key important distinction is that this more gentle simulated fader dip on a source expander is usually more stealthy and makes it less audible as an effect . Using a gate for a vocal is often problematic because of the subtle trailing and ‘ crescendoing from nothing ’ sort of nuances of voices ( and of many instruments as well ). The traditional gate doesn ’ t work as reliably , or it is super noticeable in these cases . A source expander allows you to have a softer and more musical way to reduce bleed for your most important sources . It can also be helpful when gain before feedback is an issue .
[ WM ] Is this something you would use at FOH and Monitors and all sorts of sources ?
[ Mike ] I don ’ t think there are hard lines and super clearly defined edges for uses of any audio tools . If it works for you , use it . But there are common applications where you ’ d most likely use a source expander , sure . The most common would be a lead vocal or a pastor mic — your most important source that you need to stand out in the mix . Personally , I use source expanders in monitors as a way to tighten up the mix and keep necessary bleed out .
For years and years , I would actually ride the fader up and down manually , and I still do to some extent . These key channels are naturally going to be a focus and usually the loudest thing in the mix . But when that vocalist or instrumentalist isn ’ t active , you ’ ve got something boosted and sitting at the top of your mix that is just taking on bleed . The manual way to manage this is to ride the fader , but this isn ’ t foolproof , and you need to know the music very well and you need to be on your game 100 %. With a source expander you can be much more reliably managing these adjustments on the fly .
While this key channel sort of application is quite common , we do see the source expander pop up in other ways . Because of how source expansion is implemented in dLive ( on every channel without added latency ) engineers are now using it in all kinds of places where previous limitations ( like channel count or latency or system resources ) might have made it impossible . I ’ m seeing folks replace their gates on drums with the Source Expander or the Dual Threshold Expander . We ’ re seeing it on guitars , etc . There is no ‘ wrong ’ place to use it if it is giving a benefit to your mix .
[ WM ] Ok , so the concept behind a source expander makes sense . It is like a more musical and ‘ transparent ’ gate . You also mentioned the Dual Threshold Expander . What is that ?
[ Mike ] You might not have heard of the Dual Threshold Expander since it is a relatively new tool that Allen & Heath has released within dLive . It is available on every channel and gives you a bit of a combined ‘ traditional ’ gate and source expander in one tool . In a gate you would have a Depth control , which is how much gain is reduced . You have the same in a source expander . In both tools ( a traditional gate and the Dual Threshold Expander ), when the source material is below a threshold , you get a depth of gain reduction . Again , this is meant to cut out unintended signal most traditionally .
The main difference of the DTE is that you can define both an upper threshold and a lower threshold so effectively a ‘ range ’ for your expander to work in . The ‘ ratio ’ of the expander in this case is controlled by the Depth and lower threshold . It kind of ‘ softens the blow ’ of the gate opening in this way . Technically , in a gate the gain reduction is fixed below the threshold ( think of the mirror image of a limiter , but only to a certain level defined by the Depth ). In a traditional downward expander the gain reduction is roughly linear ( think of the mirror image of a compressor ). So-called source expanders often add a bit of a ‘ soft knee ’.
Maybe this simplified definition rings for you ? The Dual Threshold Expander is like a source expander stacked on top of a gate — working as one tool . I ’ d guess that is the probably the easiest way to think about it . All of the tech talk aside , once you are on a desk and playing with it , it becomes quite intuitive and makes sense pretty immediately .
[ WM ] What do you mean by having access to these tools ‘ within ’ the console ?
[ Mike ] Well , in the hardware versions of source expanders you are easily looking at hundreds of dollars per channel for the tool . These units are almost akin to guitar pedals where you ’ d toss one in line with a channel and route it back to the desk . If you want more channels of the effect , buy more hardware racks . With external plugin versions you still are doing this type of roundtrip ( digitally ) and you have to really work to get things phase-aligned and calculate the added latency , etc . A bit more cost effective to add more channels in the digital plug-in realm once you have the effects system running , but still not without some caveats .
With dLive you essentially get 128 source expanders for free . Well , I guess you do have to buy the console first , but you also would have to buy the console in the external hardware and digital plug-in scenario . The key difference is that once you have your dLive , you ’ re set . Call up the channel , select and enable Source Expander and go to town . For sources like drums , maybe alternate and A / B between a more traditional gate and the Source Expander and see which one you think sounds best . Throw in the Dual Threshold Expander and play with those parameters and get a feel for how that helps clear things up and creates some extra space for your key sources in the mix .
[ WM ] Thanks for the chat , Bangs !
Jeff Hawley A 20-year music industry veteran — equally at ease behind the console , playing bass guitar , leading marketing teams or designing award-winning audio products . He currently heads up the marketing for Allen & Heath in the US .