FRONT OF HOUSE
LEVEL UP : DEALING WITH UPS AND DOWNS | Kent Morris
Livestreaming has brought a new twist to mixing : loss of control over the end result . In a live event with an audience in an enclosed space , the engineer provides a balanced sound for people in the room with a shared output section , the speaker system . Everyone present is hearing the same system in the same environment , making it probable the mix is pleasing to a plurality of listeners . In essence , a communal basis is established . Livestreaming , on the other hand , takes control out of the engineer ’ s hands and onto CDN algorithms for upload and download and then on to the user ’ s personal listening device , whether it is a phone , laptop or TV . How , then , do you create a mix you can ’ t hear ?
The first strategy is to consider the most likely manipulations to occur downstream and prepare for them . For instance , CDNs seek to level balance and frequency limit audio , so their approach is to look at any audio signal outside a narrow window and bring it back in line with their predetermined optimum . As a result , a mix with wide dynamic and frequency range will trigger the algorithm in the network to compress with a heavy hand . To prevent this , build the livestream mix with less level variance than is normally used for a room mix and go ahead and bring fourth-order ( 24dB / oct ) high pass and low pass filters into play , set in the neighborhood of 100Hz and 14KHz , respectively .
Next , think about the internet connection the user will employ . If your congregation is generally blessed with reliable , high speed service , you can probably get away with a more elaborate mix , but if their connection is often slow , pre-empt trouble through the use of a sparse mix with prominent vocals and light use of effects . It may even make sense to remove some of the cymbals and electric guitar from the livestream mix in an effort to parse it down to its essential elements .
Third , contemplate the playback device the listener will use . Most people use a phone or laptop when livestreaming a service , so forego the low-end tilt while also abstaining from accentuating the high end with a shelf . It is safe to assume the playback device will not employ 18 ” subs and 5000 watt amplifiers . The speakers will be on the order of ½ ” in diameter . The onus then , is to build a mix with impact based on these restrictions . One helpful thought is to lower the response in the 3.5KHz range in order to make the mix appear broader than it is . Most phones and laptops have DSP onboard to boost the upper mid-band and some have psycho-acoustic processing to create artificial low-end , but many do not ; making it impossible to guess how the mix will translate and leaving a flattened curve with one or two judiciously applied cuts as the best option .
Then , work to avoid Zoom-type product use at all cost . Zoom and its kin are designed for multiple spoken word participants and use complex algorithms to balance the levels among the users while keeping ambient noise at bay . Just as with a Dugan Automix circuit , Zoom is an anti-music mixer . It creates useable talking head meetings , but terrible music productions .
Finally , invest in a mastering leveler , whether in hardware or software ( plug-in ) form . These devices can be set on the final output to maintain consistent levels while preventing clipping though limiting . Since they are the last point before upload , they are able to correct issues while the mix engineer is still in control of the process .
Livestreaming presents a unique challenge by forcing us to mix what we can ’ t hear , but that doesn ’ t mean we are powerless . By narrowing the level and bandwidth we use while streamlining the mix elements to a minimum and then inserting a watchdog at the end of the chain , we can deliver a mix that is both useful and pleasant .
Kent Morris Kent is a 40-year veteran of the AVL arena driven by passion for excellence tempered by the knowledge digital is a temporary state .