So you’ve got passive speakers and need an external amplifier. Awesome. But it’s not as simple as just connecting the cables, turning the dials to 11 (see Spinal Tap) and walking away. There’s different modes to choose from and they all have different impacts; like how many speakers you can use, how much wattage of output power you get, how you need to run cables into and out of your amp, etc. For the sake of consistency, let’s assume for the rest of this post that we’re using a 2-channel Amplifier. Let’s start with Parallel Mode: Parallel mode allows you to run the amp in Mono. You send an output from your mixer to Input 1 (channel 1) on your amp and the amp internally routes the same signal to Channel 2 as well. Benefits of Parallel Mode: - Convenient Cabling: You don’t need a Y-cable or multiple outputs to send the same signal to both channels; the amp does this for you. - More Speakers: You can run more speakers in a chain. Because you’re running a single signal to both channels, you effectively double the total capacity for your speakers. Just make sure to do the impedance calculations for amp safety. - Fewer Amps Needed for One Output: When you have a lot of speakers in line with each other and you’re okay with only being able to control independent channel levels on your amplifier (I.e., not your mixer), this is a great option to cut down on the number of amplifiers you need. - Higher Volume: Reduces total impedance, allowing the amplifier to deliver more current and power. - Redundancy: Signal is not linear in the chain. If one speaker fails, the others continue to function. - Sound Quality: Better for speakers with internal crossovers (like 2-way Hi-Fi speakers) as it maintains correct frequency response. Cons of Parallel Mode: - Channel Loss: You can’t send different signals to each channel. - Too Few Amps for Many Outputs: If you have front fills, delay lines, and subs, you might not have enough amplifiers to afford to lose an entire differentiated channel. - Inconvenient Control: You don’t have independent control from the tech table/FOH position. You need to either walk over to the amp or have an A2 who can adjust levels for you. You do have independent amp channel control though, so you can adjust the level of one channel without affecting the other. - Potential Low Impedance: You have to be mindful of how low your impedance is getting: assuming speakers are all the same impedance, parallel mode calculations divide speaker impedance by the number of speakers in the chain (e.g., two 8 ohm speakers in a chain means impedance is 4 ohms - check the impedance rating of your amp and don’t go any lower than that. Most amps can only handle a minimum of 4 ohms (some can handle 2 ohms). - Higher Likelihood of Damage: If you fail to consider impedance implications in this mode, you can damage your amp/speakers. - Heat & Stress: The amplifier works much harder to provide more current, leading to increased heat.

Here’s a great video from Shure on radio frequencies and wireless kit best practices. https://youtu.be/JKdqeMDj8iU?si=A1ufpLv1SFXKTiPW Here’s my summary if the video is too long for you: (Keep in mind I’m paraphrasing) Omni are good for indoors because they capture surface reflections and aren’t directionally biased but generally less powerful and less reliable over longer distances. Each whip should be facing 45 degrees to the side of the receiver to increase the range of movement of the transmitter without signal loss. Directional are great for outdoors especially over longer distances but need to be high enough to gain clear line of sight with no people in the way and directly aimed at the transmitter. Conical/helix are great for when transmitters have to be in isolated zones or are expected to move and shift position a lot (in degrees). High gain is more important for analog kits. Gain doesn’t matter as much for digital kits. This is due to the linearity of the receivers and the nature of the data transmission. Analog data is based mainly on frequency, amplitude, and phase modulation, subject to noise that needs to be squelched when present, and is generally just lower quality. Digital data transmission involves binary bitstreams that represent the same analog information as well as information about the reliability of the data in antenna A versus antenna B, or in all 4 antennas as a majority consensus in Quadversity mode. 1/4 wave, 1/2 wave, and full wavelength are lengths of antennas and the waves they are sensitive to. Smaller wavelengths use smaller lower power antennas. The converse is true as well. You want to keep your antennas as far away from each other as possible, but at least their respective full wavelength. One full wavelength is 3-4 feet, so 1/2 wavelength would be 1.5-2 feet, and 1/4 wavelength would be 0.75-1 foot. Best practice is at least 10 feet though as the further the better. But you also need to consider signal loss and type of antennas. It’s best not to mix and match. Use the same type in A and B to avoid drop out.

Sometimes you’re setting up in a room that’s shaped like a shoebox; very wide but not very deep. This means sound from your speakers is probably slapping off the back wall and creating unintentional reverb that can kill the intelligibility of speech for both listeners and presenters. Not good. So, how do you fix it? You can’t reshape the room, but you can consider changing your speaker placement if that’s an option. Let’s say you’ve got two clusters for mains (4 speakers) and two side fill clusters. That’s 8 speakers total but only 2 zones. Your goal is to be able to decrease the volume enough that sound dissipates before reverberating off the back wall. But here’s the problem: you won’t have even coverage with your current setup. Solution: separate your clusters and spread out your speakers so that you have no dead spaces i.e., more zones. Then decrease each speaker’s output gain until you find the best volume for reaching the listeners in the back without generating too much room reverb. Or better yet, think about the shape of your room beforehand so you have the correct setup in the first place! Summary: Wide, shallow rooms that are prone to excessive room reverb require multiple zones of point-source audio. Side note: you also want to keep your speakers away from walls as much as possible to avoid the boundary effect.

Let’s look at: - Which Listening Environments Need Delays? - What Problem Do Delay Speakers Solve? - What Problem Do Delay Speakers Introduce? - How Do We Solve These Problems? Which Listening Environments Need Delays? Delay Speakers are only necessary in very deep rooms, where in order for the people at the back of the room to hear just as well as the people at the front of the room, you (the sound tech) have to turn your Main Speakers up past their ideal volume until they’re unreasonably loud for the people in the front. What Problem Do Delay Speakers Solve? The main goal of sound reinforcement is to create a listening environment where sound is distributed evenly and with the same acoustic qualities, which ensures that every listener gets the same listening experience regardless of their listening position in the room. So obviously, if the room is very deep and we only have one line of speakers in one depth position (our Mains), we’re going to run into the problem I just outlined where either it’s too loud for the people in the front or too quiet for the people in the back. This is the problem that delay speakers solve. By placing speakers in different depth positions in the room, we can have speakers that are placed closer to our listeners in the back, which allows us to maintain an ideal volume for all of our speakers and all of our listeners. What Problem Do Delay Speakers Introduce? However, delay speakers also introduce a problem that we didn’t have before. The problem is asynchronicity. In order to explain this problem, I’ve got an analogy for you. Let’s say we’ve got 3 people in a racetrack and they’re going to have a race. Person 1 is 100 feet from the finish line, Person 2 is 50 feet from the finish, and Person 3 is 25 feet from the finish. Assuming they all start at the same time and they all run at the same speed, will they cross the finish line at the same time? Of course not. Person 2 gets to start closer than Person 1 and Person 3 gets to start closer than both of them! Based on the current rules, Person 3 will finish 1st, Person 2 will finish 2nd, and Person 1 will finish last. Another way of saying this is that they will run asynchronously. They won’t move through the same space at the same time.

This is a fantastic tutorial for learning to use Shure Wireless Workbench for setting up your wireless network, scanning, and deploying frequencies.