SW4™ Using & Applications

The following page describes the basic approach to using the SW4. For simplicity, we have chosen to describe the SW4's functionality using two wireless microphones, but any two sources may be used. For more complete details, click on the icon at left to download the full manual.

Basic Set-Up

Before making connections, make sure all signal levels are turned down. This will avoid loud pops that could damage more sensitive equipment. Set all of the SW4 channels to the start position as follows:

  • AB select on A (LED on A)
  • Trim set fully clockwise (5 o'clock)
  • Bus switch out (off)
  • A+B switch out (off) This function is only on channel-1
  • Link switch out (off)
  • Top panel ground lift switch set to ground

There is no power switch on the SW4. As soon as you connect the power supply, the SW4 will spring to life. Connect the XLR output from your primary wireless receiver to the A input on channel-1. Connect the second (backup) wireless system to the B input on channel-1. Connect the channel-1 XLR output to your mixer.

Slowly turn up the volume and test to make sure the first wireless system is working. An LED indicator showing signal presence will flash. If OK, switch to B. Both systems should be about the same loudness. If you notice one being louder than the other, reduce the louder system using the trim control. As the SW4 is transformer isolated, it is doubtful that you will encounter hum and buzz caused by ground loops or stray DC voltage. If you do happen to hear some noise, try lifting the ground by toggling the switch on the top cover. Repeat for subsequent channels.

Linking channels together

You can control two or more AB channel switch functions at the same time by linking adjacent channels together. For instance, you could link channels 1 and 2 together to create a stereo switch for a backing track, while leaving channels 3 and 4 as individual channels for wireless switching. To link, simply depress the LINK switch on the right of the channels. All four channels may be linked together if desired.

Remote Switching

The SW4 may be remotely switched using a Radial remote footswitch like the JR2 or a desktop remote control like the JR2-DT. The JR2 and JR2DT have two function switches marked AB and MUTE. Once the remote is connected, you can toggle the channel-1 AB and other adjacent channels that are linked by depressing the AB switch. When the MUTE switch is depressed, all of the outputs on the SW4 will be turned off except for the two front panel PFL monitor outputs. The front panel LED indicator will also illuminate.

Bus Output

The SW4 is equipped with a stereo bus output that can be used for a variety of functions including creating a 4 x 2 stereo switching mixer, a 4 x 1 mono switching mixer for monitoring and a whole bunch more. Channels 1 and 3 are assigned to the LEFT bus out, while 2 and 4 are assigned to the RIGHT bus out. Simply depressing the bus switch on each output activates the bus. Input levels are adjusted using the TRIM controls while the output is controlled using the front panel BUS OUT level control. A front panel on-off switch is pushed ON to activate.

The bus output offers a choice of balanced XLR and unbalanced 1/4" connectors, all of which are transformer isolated to help eliminate hum and buzz caused by ground loops. The ¼" connectors are intended for guitar amplifiers with a choice of mono, using the top (LEFT) connector, or stereo outs when both jacks are in use. A trim control on the top panel is used to reduce the output to match guitar amp setups and is augmented with a separate ground lift switch to help eliminate ground loop noise.

PFL and headphones

Each channel on the SW4 is equipped with a 3 position PFL switch (Pre-Fade Listen) that routes the A or B signals to the headphones and front panel MONO out. You could, for instance, listen to the artist using headphones and then test the backup mic by selecting B. This will not affect the signal going out of the channel or the bus. Set the volume control on the headphones completely counter-clockwise (7 o'clock) or to the off position. Move the AB switch to either the A or B position. The red PFL light will illuminate next to the headphone jack to let you know the system is ready. Connect your headphones to the PHONES jack, and turn up the volume slowly until you have reached a comfortable listening level. Be careful! The headphone output on the SW4 can be set quite loud so that one can audition channels during live concert environments. The use of headphones is only intended for short periods and by professionals that are familiar with the potential for hearing loss due to over-exposure. Please consult your local health authority to ensure you do not put yourself at risk.

When set to the middle (OFF) position, the headphone out will automatically connect the BUS signal so that you can hear what is being routed to the main bus outputs. The MONO output above the headphones follows the PFL. This can be used for a guitar tuner or guitar amp if you are using the SW4 with bass or guitars or routed to a wedge monitor for mono listening.


App-1 Switching between wireless systems

Most wireless systems employ XLR connections and the receivers are normally positioned near the monitor engineer. Should a problem with a wireless system occur; one can exchange the wireless and move to an alternate audio channel. But this approach both increases the channel count and adds tremendous complexity as all of the mix channels (house, monitor, broadcast, record) must be switched in sync. A better solution is to switch the wireless system at the source. Should a problem occur, you simply depress the front panel switch without ever missing a beat. The SW4 is equipped with four channels, to enable up to four artists to share the same device. Each input has a trim control to ensure the output levels from the various wireless systems are matched.

App-2 Switching between two wireless guitar systems

Most wireless receivers are equipped with a choice of ¼" and XLR output. The advantage of using the XLR outputs is of course lower noise. This could for instance be used to select between two acoustic guitars which could then feed the balanced input on a console. Another more 'timely' application is routing a wireless system to the balanced input of a digital processor. For the electric player, we added a top-mounted mono switch and two guitar-amp ready ¼" outputs to feed a stack. These are transformer isolated to eliminate hum and buzz caused by ground loops. We then incorporated a 'set & forget' level control so that the signal can be adjusted to drive the amp and a mono output so that the guitar tech can check the system status at all times.

App-3 Combining two wireless inputs

In some situations, you may want to have two wireless microphones or guitars on at the same time. It could be for a presenter that moves from a handheld mic to a head-worn mic, or maybe a guitarist that likes to have one guitar 'ring out' or while it sustains away, have a second guitar already on the go. To address this need, we added a blend function on channel-1 that uses a passive summing mixer to combine the two inputs. Simply set the trim control for the appropriate mix and away you go. Note that because this is passive, the mix reduces the sensitivity by 6dB which means you will have to compensate by increasing the SW4 bus output or the guitar system's sensitivity.

App-4 Switching between stereo backing tracks

Today it is 'standard fare' for the artist to support their show with backing tracks. The SW8 has become omnipresent in professional touring for this very reason. But there are situations where eight channels of backing tracks may not be required. This could be to switch between the stereo outputs from a couple of laptops.

Stereo switching is easily accomplished on the SW4 by linking adjacent channels together using a recessed front panel LINK switch. By linking channels 1 and 2 together, you can route both left sources to channel-1 and the right sources to channel-2. Depressing the channel-1 AB selector will switch both channels simultaneously to the backup system. You can also route the outputs to the mix bus to cue up tracks in between sets and use the PFL and headphones to check to make sure the tracks are playing in sync.

App-5 Switching between the band and the DJ

In larger clubs, switching between the band's mixer and the DJ is often desirable. This enables the DJ to perform while the band is setting up and then instantly switch when ready. The advantage to switching means that you do not have to share channels in a common mixer or sub-mix one mixer into another which will introduce more noise and distortion. By linking channels 1 and 2 together, stereo feeds from the band's mixing console and the DJ can be switched. As the outputs are isolated, hum and buzz due to ground loops and DC offset noise is eliminated. One merely adjusts the input levels as needed. If you are concerned with an overzealous DJ or mix engineer, a limiter can easily be introduced. The on-board headphone amp and PFL enables the system tech to check the B source before going live.

App-6 Toggling between two consoles at a festival

Today's line-array PA systems no longer suffice with mere stereo. The engineer must address both the left and right stacks along with the front fill and subs. So switching from one artist to another also means providing each engineer with full access to the various PA stems so that he can achieve his desired mix. The SW4 is well suited for this as all four channels may be linked together and switched simultaneously. Ch-1 would be assigned LEFT, Ch-2 RIGHT, Ch-3 front fill and Ch-4 could be assigned to the subs. A pure copper signal path with 'big-ass transformers' ensures almost unlimited bandwidth and a dynamic range that far exceeds the output of most consoles.

App-7 Using the SW4 as a backup for AxeFX

More and more artists are reverting to digital sources for their electric performances. The reason for this is not so much preferred tone as it is simplicity and consistency. Considering most artists nowadays employ in-ear monitors, the variables with live guitar amps and ever changing acoustics have led many to go the digital route. But this fix introduces a new problem: one of dependability. Just as most touring professional always have a second guitar amp on stage for backup, the computer inside the digital guitar box is subject to glitches and failure. This has led many to look for a solution that enables quick switching on stage. For the tube guitar amp player, the Radial Headbone is often used. Here, the SW4 comes to the rescue.

App-8 Expanding for more channels

Although 4 channels is likely more than anyone will ever need, there may come a day when the SW4 will be called into action and need to be combined with a second or third unit for a special application. This could be for a larger playback system or switching some form of matrix. To address this need, the SW4 can be remotely switched using a standard contact closure via a ¼" jack on the rear panel. A second ¼" jack acts as a contact output to enable multiple SW4s to be used in tandem.

App-9 Using the SW4 as a an effects or signal router

When testing microphones; being able to compare a 'wet' or processed signal with the original can prove to be very beneficial. For instance auditioning a pre-EQ or pre-compressed signal and the comparing it to the end result can help the engineer make important mix decisions. To set this up, parallel channels are set up – one dry, the other wet – and these are fed into the SW4 and instantly switched.

Final thoughts

It is important to note that much effort was invested to make sure the ergonomics were addressed. For instance, although we wanted to make it easy to switch channels, we also wanted to make it difficult for errors to occur due to accidental switching. For this reason, many of the functions are recessed so that they may be 'set & forgotten'. We are confident that once you have worked through the application in mind, the recessed switches and knobs will be mostly left untouched for the duration of the tour.