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Wire-Lists #33: Hey! What's That Sound?

Social Media WireLists33 300pxTroubleshooting Possible Reasons For What You're Hearing

Our Service Department are like mechanics in that we frequently get calls that start with, "I turned on/was using my (product) and heard this sound..." This list will discuss the types of sounds you might hear and give you some examples, along with what you can do to help figure the root cause/s of the issues.

In order to help troubleshoot, we need to know (or you need to consider):

  1. What were you doing? Specifically, we need to know what happened proceeding the sound. Did you just turn the unit on? Was it working normally prior to when you heard it? Is the sound coming from your transmitter or your receiver…or are you not sure because you are hearing it in earphones? Is a mic attached? Did you hear the sound once, or is it intermittent or constant?
  2. What is the application? How are you using your equipment, and in what environment? With a mic or without? What frequency are you using, and is there other equipment working with it or near it?
  3. Have you ruled out ambient noise? Occasionally and especially if you are working in a noisy/busy environment or one that you know has a great deal of interference, you’ll want to ensure that what you hear is really within the equipment and not outside.

To follow are seven scenarios that you might experience. Please note that these are not absolutes, and what you hear or experience may differ. We share these because they are indicative of the nature of a particular situation and give you a good starting point on what to look for:

1) 2.75k whine/warble with SMWBs (including SMDWBs)

There are two types of sounds that may indicate a problem with your transmitter: a whine and a low-pitched warble. The whine is triggered by the Remote setting (i.e. “RC ON”). The warble is triggered by using a frequency evenly divisible by 12, which we explain in a bit.

The Whine

The graph below shows the “Remote” noise as a 2.75kHz whine and it appears on all frequencies. This clip is what it would sound like:

SMWBE07 SN 125 whine

The fault goes away, as you can see and hear, if the Remote is set to “RC OFF”. This graph shows the results of this remedy, as well:

SMWBE07 SN 125 no whine

If you have units with this issue, we have a fix! Please reach out to our Parts & Repair department at 800-821-1121 or This email address is being protected from spambots. You need JavaScript enabled to view it..

The Warble

As previously mentioned, the warble appears on frequencies evenly divisible by 12. A1 frequencies that will have this issue are: 480.000 MHz, 492.000 MHz, 504.000 MHz, 516.000 MHz and 528.000 MHz. B1 frequencies that will have this issue are: 540.000 MHz, 552.000 MHz, 564.000 MHz, 576.000 MHz, 588.000 MHz, 600.000 MHz and 612.000 MHz (EU only) No other frequencies exhibit the warble. We contacted customers for whom this might be an issue and retrofitted their units with an internal modification that we have since addressed in the fabrication process for units manufactured recently. If you have had your unit for a few years and it has not been modified and you are experiencing whines or warbles, contact our Parts & Repair department to ask about it at 800-821-1121 or This email address is being protected from spambots. You need JavaScript enabled to view it..

2) SM and variants (SMa, etc.) with a legacy mic

Are you using several SMs – some old and some newer - and you notice noise on some but not on the others? Have you had service done where the Audio/Logic PCB was replaced with the newer version of PCB (when used with non-servo mics)?

Some users have reported that their SM unit/s exhibit a low-level whine, and example of which you  can listen to here: 

In the example, we tested this with no microphone attached and were able to hear the whine in the audio, but had to greatly increase levels out of the receiver to hear it. However, the whine with no microphone attached also went away if the Remote was set to Ignore.

The reason for this happening has to do with the servo bias input circuit wiring and the difference in specs between the voltage offset parts. In late 2018, we changed the op-amp in the servo bias input from SIA7301 to SIAAD8605, which in turn changes the wiring method.

The older, non-servo wiring method is:

  • Shield to Pin 1
  • Bias (likely red) wire to Pin 2
  • Audio (likely white) to Pin 3
  • Wire jumper from Pin 4 to Pin 1
  • No connection to Pin 5

When we changed to SIAAD8505, the following changes were made to the older method:

  • Bias (likely red) to Pin 3
  • A 1k resister between Audio (likely white) Wire and Pin 1 (for servo-only, this would be Pin 5)
  • Wire jumper from Pin 4 to Pin 2

For the units that are exhibiting the error, you will need to switch to a different mic, or have your ground shield wired accordingly. We cover 5 input jack wiring in our Support article on wiring.

3) Signal to noise ratio and the noise floor (audio gain and gain structure issues)

Signal to noise refers to the relationship between how strong the useful signal is verses the noise you don't want, and noise floor refers to how strong the noise is. In any system, you will also have some level of noise. Your device interprets signal quality through the signal to noise floor. Input gain is the most important adjustment on any wireless system, and the gain must be fully modulated to give the system as much signal as possible to work with. Gain that is too low accounts for the majority of noise complaints that we receive. The following resources will help you correctly establish gain structure: *Tech Note 1016: Transmitter Audio Gain vs Signal to Noise Ratio

4) Antenna Whip (or Slap) in Transmitters

All transmitters have some antenna whip (movement) noise. If it sounds excessive, you can run the following test:

  1. Attach a microphone and set your gain with a voice test until you have full modulation on the transmitter;
  2. Monitor the output from the receiver with the audio at a comfortable listening level;
  3. With the microphone attached but with no audio source, move the antenna back and forth about 45° from vertical and monitor the audio or noise. Do not increase the gain or monitoring level;
  4. If moving the antenna causes the receiver modulation to vary beyond ¼ full scale, the unit suffers from Antenna Slap.

A transmitter exhibiting Antenna Slap that you cannot fix by trying the above suggestions requires an RF board replacement to fix, which we or an Authorized Factory Repair shop can do.

5) Theremin Hum

Theremin hums are another antenna-related error in transmitters that is not common, but they happen and are very distinctive. You’ll notice it when you move your hand near the transmitter – it will make a low-pitched, variable hum, inversely relative to how close your hand is. Imagine it as the “power” sound that was used in old Sci-Fi B movies. It is caused by spurious emissions, which are harmonics or other signals outside a transmitter's assigned channel. A transmitter that is exhibiting a Theremin hum needs to return to us for service.

6) High Frequency Whine With Power Supply Bricks

This can be heard in the power supplies for the DSQD, M2T and Venue 2). Users sometimes mistakenly think that the sound is coming from the transmitter or receiver, when it’s actually coming from the power brick. The way to test this would be to try another power supply – or a different, compatible type. If the sound goes away, there’s your answer! If this isn’t a possibility, place the power brick in a different location, ideally on the other side of your cart, or further away in the rack.

7) Bad Regulator

This is a rare one, but it happens, especially in units that are older and have had a long use life. We build products to be very durable and have had many units in the field for 20+ years, but like everything else – cars, appliances, and yes, even the human body – units wear out and show age after a while. A receiver with a bad regulator will release an intermittent sound that changes pitch, similar to a Theremin hum. Units with bad regulators are easily repaired but would need to be sent in for service.

Sound issues can be tricky to diagnose, but we’re always here to help. This email address is being protected from spambots. You need JavaScript enabled to view it. or post a question on our Facebook group, which always has a few active threads from other users, trying to troubleshoot sound anomalies. Remember, also, that like doctors, we have to evaluate the entire system to diagnose and repair issues. If you send your unit to us or an Authorized Repair technician, please remember to include the microphone, power supply and any wiring so that all parts can be tested.


Wire-Lists #32: 4 Quick Tips for Antenna Performance

Social Media WireLists32 2 300pxWe've covered antennas for transmitters and receivers in a few of our previous Wire Lists. This week, we share 4 quick antenna tips that we might not have touched on prior:

The Straw Hack

Wireless signals are readily absorbed by anything containing water, which is why we advise not to let transmitter antennas touch the body or skin since this will reduce range due to the attenuated signal. What do you do in those situations where this is inevitable? Grab a straw! A regular drinking straw – opaque or clear both work - cut to the size of the antenna and slipped over it, will prevent skin contact and ensure that your signal remains strong. Another variant of this approach is to use aquarium air tubing.

Watch Where You Put It & Don't Bend It

Wireless systems depend on the full length of their antennas to deliver the strongest signal. When placing transmitters on talent, have them move to ensure that the antenna will not be bent or caught in, say, a belt or garments. Bending the antenna, even accidentally, cuts down on its efficiency.

But You Can Angle It

If you have two antennas that have to be close together, you can tilt them so that they are 90° angled to each other - one 45° to the left and one 45° to the right. Most Lectrosonics diversity receivers combine both antennas either in or out of phase with each other. By angling the antennas away from each other, a greater overall spacing is achieved between them and thus each antenna “sees” more of a different set of direct and reflected signals. In many cases, the performance difference of this arrangement may not be any different than having the antennas parallel. But in some situations, this will make a greater difference.

Give It Space

We have seen receivers, particularly when used in location mixer bags, perform poorly due to the close proximity of camera hop and IFB transmitters, also located in the bag. Frequency separation helps – the more spacing you can give your hop and IFB transmitters from your receiver frequencies, the better – but physical separation or remote antennas may be required for proper operation. One nice solution for bag systems is the coax dipole an item we sell for both BNC and SMA antenna connections, or you can make yourself.

And just a word about RF amplifiers and amplified antennas – the ideal amount of gain is “just enough to overcome the loss through coax cable” and generally, passive systems with correct gain structure will out-perform active systems, especially if too much gain is applied. Often, it is better to have a bit of attenuation through the antenna system – up to 6dB, in fact, rather than unity gain, especially in high RF noise environments.

Need additional pointers for your unique antenna situation? Post to our Facebook group. Our users often come up with hacks that we hadn't thought of but prove worthy in real life situations. Feel free to share yours if you have them!

Wire-Lists #31: Improving Signal to Noise Ratios with PF25 Filters

Social Media WireLists31 300pxIn today’s list, we’ll discuss improving Signal to Noise ratios using PF25 filters.

Filter 1 List 32

This first image shows a wideband scan using a Venue 2 with A1, B1 and C1 modules, and a pair of SNA600a passive dipole antennas. The blue arrows indicate our intended carriers from transmitters about 10 ft. away from the receiver antennas.

Filter 2 List 32

In the second scan, we have included an RF Filter on both antennas, allowing mostly only energy within Block 20 and a bit on either side into the receiver. Our PF25-20 is a small, low loss bandpass filter with a width of approximately 26 MHz. (the same of the Lectrosonics “Blocks”), which decreases the RF signals above and below the determined width. For example, a Block filter 20 will attenuate frequencies below 512 MHz and above 537,500 MHz. You can learn more about Blocks for PF25 here.

Filter 3 List 32

In this third scan, we have replaced the PF25-20 filters with a similar pair on Block 25 (PF25-25). Here, you can see that most of the energy outside of Block 25 is heavily attenuated.

Filter Q&A

How does a filter help me?

When coordinating frequencies, our goal is to maintain the best signal-to-noise ratio of the carriers. By using a filter, unwanted noise is significantly reduced, improving the performance of the system since it must process less overall RF energy. This can increase the range of the system and reduce intermodulation and other RF noise sources.

How is it installed?

Being a passive filter, the PF25 must be connected between the antenna and the receiver without any additional requirement. Of course, one filter should be used for each antenna.

When should I use it?

Filters are ideal in spaces where the RF spectrum is heavily congested either by many wireless systems in the same location and / or by TV channels.

But won't I be losing RF bandwidth?

Applying the filter will reduce the selectable bandwidth, but you can make better use of the space that is actually available.

How do I coordinate the new bandwidth in the frequency calculation software?

If you are using our Wireless Designer software, simply assign the same “narrowband” filter block in the transmitter option of the channel (s). If you are using other software, you only need to adjust the bandwidth for that channel to match the one on the filter (most popular software contain our blocks by default).

I have free space in my RF spectrum and low noise floor. Do I need to use filters?

If this is the case, the filter will not make a major difference. The greatest effectiveness of the filter is in problematic RF locations.

Can I use this filter with equipment from other brands?

Of course! Just check that the filter bandwidth is compatible with your equipment.

My receiver already has built-in filters, should I use an external filter?

Any additional filters will help if your spectrum is difficult.

Will a filter give me more transmitter-receiver distance?

If the space is congested, the filter will always be useful in improving the Signal / Noise ratio by reducing the noise. But if the spectrum is clean, applying a filter will not make a difference and may even slightly attenuate the carrier.

We’re here to help with any questions about Signal to Noise or filters. Reach out by This email address is being protected from spambots. You need JavaScript enabled to view it. or open a thread on our Facebook group.

Wire-Lists #30: Maintaining Social Distancing With Dante-Enabled Equipment

Social Media WireLists30 300pxPreparation and monitoring are big parts of any production that involves sound, and all productions involve multiple pieces. Even in a wireless world, you are still having to place, adjust and touch every piece of that system: microphones, amplifiers, the mixing set-up. And now, having to do that while maintaining cleanliness and appropriate distancing just multiplied the hands-on portion of your entire crew’s jobs. Distance isn’t your friend when it comes to sound, because as you know, increasing the distance between your transmitter and receivers can create unwanted noise. These are all non-issues if you're using a Dante-enabled system!

What Is Dante? Four Reasons Why It's Awesome.

Developed by Audinate Pty. Ltd., Dante (an acronym for Digital Audio Network Through Ethernet) technology replaces both wireless and wired connections with a computer network that allows multiple signals to be conveyed through a single CAT5, CAT6 or fiber optic cable. The Dante software or hardware in a device segments digital audio signals and wraps them into IP packets that can be routed along a network, resulting in multi-channel, low-latency digital audio over ethernet.

1) Single, Consistent Point of Contact

All devices on the network can receive signals no matter where they are physically located. The routes and settings are saved within the Dante device, so no need to re-establish connections if one piece is moved or power cycled. Adding additional equipment to the network is as simple as adding them to an available network jack.

2) Very Easy To Deploy and Use

Signal routing and system configuration with Dante is fast, simple, and flexible with the free Dante Controller software. It automatically discovers each device on the network, enabling you to instantly route audio, label devices, and configure the network with a few mouse clicks.

3) Excellent Audio Quality

Since there are no cable runs, the audio conveyed through Dante is free from quality degradation and network noise, with unnoticeable latency.

4) Unlimited Channel Capacity

Since Dante is essentially a network, you can add as many channels as your interface and Ethernet switches can support. If you need additional capacity, you simply add additional interface devices and switches. The bandwidth used per port is minimal, while the channel capacity is huge. As an example, if you're running 64 channels in 24 bit on a gigabyte network, you will only use 1/8 of the bandwidth (74 megabits per second) on a port. So, you could conceivably run a minimum of 512 bidirectional audio channels at 24 bit/48kHz on a single port.

Lectrosonics presently offers a number of Dante-enabled products including two systems (transmitter and receivers with accessories). They can link to each other as well as to systems from other manufacturers, as long as those other devices are Dante-enabled:

1) M2 Duet System 
Consisting of the M2T Digital IEM Transmitter and IEM Receiver, this system houses two independent stereo transmitters, allowing for up to four stereo or dual-mono transmissions in a single rack space.

2) DSQD (D-Squared) System

The DSQD system packs four wideband receivers, with analog XLR and Dante digital outputs, into a compact, half-rack chassis footprint. The DSQD is backward compatible with any Digital Hybrid Wireless transmitters including the SM Series, LT, HM Series, SSM, HH Series, UM400, UM400a, LM Series, MM Series, and WM. It can also pick up channels from an M2T duet transmitter or a DCHT portable stereo transmitter.

Both the Duet and D-Squared Systems interface with our Wireless Designer software. Available for both Windows and Mac, Wireless Designer allows you to see and manage all of your connected devices, in addition to coordinate and recalculate frequency, without touching any of the individual components. We dive into tips and tricks for Wireless Designer in Wire List #9.

We also offer a series of Dante-networked audio processors to integrate digital and analog.

If you are new to Dante, you might find Audinate's White Paper, which we host on our Support site, which dives deeper into the technical considerations, useful.

Aaron “Cujo” Cooley and Scott Beatty, Lectrosonics users on the YouTube Atlanta Sound Guy channel, put together two videos on post-Covid production that you might find helpful in your own work:

Of course, you can always reach out to us at This email address is being protected from spambots. You need JavaScript enabled to view it. with specific questions.

Wire-Lists #29: 4 Tips to Improving Your Wireless Signal To Noise Ratio

Social Media WireLists29 300pxSignal to noise (s/n) ratio is the level of signal power in relation to the power of noise surrounding that signal, measured in decibels (dB). With wireless systems, the quality of your sound is largely dependent on achieving the highest signal to lowest noise ratio possible. So how can we do this? First, we need to look at the cause and type of noise in question. "Noise" is any type of competing signal interference – unwanted tones, static, even other frequencies - within the physical space. If you’re using wireless microphones, your noise may also be a result of channel noise in the FM process. “FM,” because all analog wireless systems use frequency modulation to send audio signals. A component of the FM process is the Capture Effect: wireless receivers will always demodulate (turn into audio) the strongest RF signals within a given frequency, and that includes sounds that you don’t want.

In order to combat the noise, you’ll need to look at the physical space you’re operating in, which is your working environment and also any equipment in your environment. Four tips to consider:

1) Check the distance between the transmitter and receiver

In general, the closer transmitters and receivers are to each other, the better your signal. This is the Inverse Square Law at work. It states that the intensity of a radiated signal is inversely proportional to the square of the distance of the wave from the signal source. If you double your distance, the signal strength is reduced by a factor of four (and the reverse is true, too). When possible, use the least practical amount of unobstructed distance between transmitter and receiver.

2) Shielding

Are you getting interference from outside your venue or area? Walled structures, in combination with wireless mics, are effective shields against what might intrude from the outside, as RF does not easily travel through dense solids. Wireless mics are not without their issues – attenuation being one. We cover attenuation in Wired List #8. In extreme cases where you are indoors and still getting interference, and if you can’t change frequencies, look for sources of interfering RF and either shield them or increase the distance from them to your receivers (see #1).

3) Antennas

Directional antennas, when used correctly, can be used to improve s/n ratios. They should be affixed above head height (10 ft is a good rule of thumb), with a clear line of sight to the receiver. By orienting them so that their null sides are “pointing” at unwanted sources of RF (local TV towards, etc.) the RF s/n ratio is further improved. We published a list of common antenna combinations for our equipment in Wired List #12. If you're using coax cables to bridge distance, inspect them before use, as wear and defects can cause a loss of signal. All coax cables result in losses of signal strength, depending on the cable material and length. Some systems may benefit from in-line filters such as our PF 25 (Link to: ) or PF 50 or filter/amplifiers, such as our UFM144. In reference to this topic and to #3 above, a powerful tool for many systems is the ALP690 active/passive antenna with selectable amplification, attenuation, and filtering.

4) Increasing Transmitter Power

If nothing else works, you can try increasing your transmitter power. Be advised that this can often result in increased noise in the general RF spectrum, which might be counterproductive. Additionally, licenses are required in some localities to operate transmitters over certain thresholds. You can check to see who the licensing body in your locality is here. Our recent Wireless Side Chat series on YouTube are good primers to review if you’re looking to improve your signal quality, because we often don’t consider the technical considerations behind cause and effect. If you missed them, they are:

#1: Introduction to RF Spectrum for Wireless Microphone Use

#2: The 7 Most Common Wireless Mic Problems and How To Solve Them

#3: Wireless Designer Software New Features, Tips & Tricks 

#4: Wireless Side Chats

#5: More RF Best Practices

Wire-Lists #28: Five Tips for Troubleshooting Wireless Mics

Social Media WireLists28 300pxOne of the things that makes wireless microphones so great is what they don't have - wires! Working wireless gives artists with elaborate stage shows, like Pink, true freedom of movement on set. But as awesome as wireless mics are, they are not without issues. In this List, we'll discuss five common glitches that you might experience with wireless microphones (and their receivers) and how to fix them.

Blocked Signal

One of the most common problems with wireless mics is signal blockage. A wireless mic is a transmitter, and anything in a wireless set-up between the transmitter and the receiver can block the signal. The typical culprits are walls or solid/dense objects on set, so you may need to move your receiver, or your external antennas if you use them, around to find a line of sight path for the RF signal. The human body can also absorb signals, which can be problematic for belt-pack units if not placed carefully. Same goes for handheld mics: make sure that they are being held properly so that the antenna is not covered by the hand. We explain this in more detail in Wire List #8.

Antennas

Bodyworn transmitters, such as you'd use with a lavaliere mic, depend on their antennas - that covered wire extending out - to deliver a signal. If the antenna is obscured or bent, your signal will be affected. Repeated stress, such as bending an antenna in the same spot, will break the tiny wires that make up the inner core of the antenna and render them useless over time. Our antennas are quite tough but with enough abuse, they can fail. Our transmitters have fixed-length antennas for specific frequency ranges, so always ensure that your antenna matches your frequency. We color-code ours to make it easy. If you are finding that your range is inadequate, consider using a directional or omni-directional antenna to boost the range. We offer several options depending on your specific need, and you can also make your own.

Noisy Audio

“Static” in the audio can be created when mic connectors are worn out, damaged, or corroded, or if there is moisture in the connector. Any movement can then create noise which is then transmitted. Be sure to keep your connectors clean, and if the metal parts become worn or the fit isn’t what it once was, consider having the connector replaced. We cover connector cleaning in Wire List # 5.

Accidental Setting Changes

Have you ever synched your mic, only to find that it changed settings again somehow and now isn’t syncd? Settings are often sent via IR, where the "window" of the transmitter is exposed to the emitter on the receiver. Usually, the range of these IR emitters is only a foot or so, but in just the right conditions, the reach might be further. To prevent this from accidentally changing the settings on one of your units, simply put a piece of tape over the IR window after you've synched. This will "lock" the setting and make sure that no other signal can change it. Just remember that the tape is there next time you use it! Tape is also useful for power switches. While our handheld has the power switch behind a sliding panel, other manufacturers have it where it can easily be toggled. A piece of tape prevents the switch from being accidentally bumped to the off position.

Interference and Intermodulation

If you are using Frequency Finder or another program to scan and choose your frequency, you may never experience interference. However, in today's crowded airwaves and when you are using multiple systems, it’s a possibility, in which case, you simply need to change your frequency for the affected units. Try switching your mic/receiver 2-4 MHz (do it in steps) up or down from where you were. Intermodulation, which we discussed in last week's Wired List, is when two or more frequencies interact, create new signals, and cause potential interference. You will frequently see this in large productions, when you have ten or more mics operating in a relatively small (frequency) space. Like too many people in one room that make it hard to hear conversations, intermodulation can be corrected by calculating for these interactions and planning your frequency occupation carefully among your connected units. This is an ideal use for Wireless Designer as you can see and keep track of all of your connected systems on one page. As you can see, most of these problems are easily diagnosed and just as easily repaired without needing assistance. Still stumped? This email address is being protected from spambots. You need JavaScript enabled to view it. or post a question on our Facebook page.

Wire-Lists #27: Advice for Navigating The Block 19/470 Overlap

Social Media WireLists27 300pxHave you ever been working with one of our systems in the 486-495 MHz range and they’re just not synching up? You might have performed a frequency scan prior to choosing your settings, so you’re sure you’ve chosen everything correctly. Or did you? You may have run into the not-common-but-it-happens Block 19/470 Overlap.

What Is The Overlap?

AdviceOverlap

As we detail in our transmitter manuals, there is an overlap in the frequency range of 486.400 - 495.600 MHz. We designed this intentionally, in order to maintain compatibility with receivers that tune across a single band. The problem only makes itself known in specific instances where you are tuning within the A1 Band on either Block 470 or 19 and one device is set to block 470 and the other one is set to block 19. This can occur when the devices are tuned manually.

The Key To Sorting This Out: The Pilot Tone Squelch

Squelching is a way to mute receiver audio to discard noise when the RF signal is too poor to produce good audio. Our Digital Hybrid Wireless® receivers use pilot tones to ensure that the receiver is quiet when turned on and off and also to mute signals from other transmitters. Intermodulation (intermod) is the interaction of two frequencies that creates unwanted distortion. We designed our units to have a different pilot tone for each of the 256 base frequencies to prevent unwanted un-squelching when an intermod lands on a receiver channel. The overlap between blocks 470 and 19 within the A1 band means you can have the correct frequency specified, but since the transmitter and receivers are set to different blocks, the pilot tones, as indicated by your hex codes, don’t match.

When In Doubt - Check The Match

Occum’s Razor tells us that the simplest explanation is usually the correct one, and that holds here. When using a transmitter on the A1 band with a Block 19 or 470 receiver, be sure that the transmitter is set to Block 19 or 470 and check the hex code on the receiver to make sure it matches the transmitter. In the example shown below, they don’t match.

Lectrosonics and frquency ban

Checking this could save you a phone call or your gear an unnecessary trip to the Mothership. For other transmitter troubleshooting ideas, check our website’s Wired List #2.

Wire-Lists #26: Developing Sanitation Protocols for Lav Work:

Social Media WireLists26 300px4 Tips For Keeping It Clean and 2 Tips For Getting Back To Business And Staying Distanced

Keeping things clean has been a hot topic lately, and social distancing also looks like it will be here to stay for a while. Most of us use lavalier mics, which require touching the talent. As we start to get back to work, how can we adapt what is a very hands-on job to be more hands-off and give our clients the safety and peace of mind that they deserve?

The AQTIS and IATSE in Canada are in the process of writing sanitary guidelines for productions undertaken there. Written by Daniel Fontaine-Bégin, Tony Fortin, Simon Poudrette and Stephan Roy, the guidelines recommend:

1) Frequent handwashing, along with the wearing of masks and protective glasses, within 6 feet of talent. Surgical gloves should be used to pass things to others.

2) The placement, adjustment and removal of lavaliers should be done at the Sound Station, using fresh adhesive. 

3) As a general rule, a solution of 70% isoprophyl alcohol - either in a liquid or as pre-packaged lint-free wipes - is preferred for gear disinfection. That specific percentage is recommended because it takes more time for the liquid to evaporate from the disinfected surface, making it a more efficient cleaner than 91% or 99% alcohol. Mix the solution in a spray bottle, which produces a fine mist and disperses the liquid without soaking what it is sprayed on. Depending on the surface to be cleaned and the shape and size of the items to be disinfected, it may be possible to spray lightly, wipe or dab with cotton swabs. Bleaching solutions, such as Lysol or disinfectant wipes, are not recommended for any gear, since they can be corrosive. 

4) Assign a disinfected transmitter and lavalier microphone for each person and store it in a Ziploc-type bag, or appropriately-identified container. After the work day, disinfect and place in a new, clean labeled container for the next day’s use. If the production budget permits, appoint a "disinfection team" (one or however many people you deem necessary) whose sole responsibility will be to ensure clean gear and make safe adjustments on talent as needed.

Distance-Friendly Ideas

The nature of lavalier mics involves touch and adjustment.  You might consider these two workarounds to make it easier to maintain distance:

5) If you use our SM transmitters, you can adjust the transmitter remotely without touching the talent by using the LectroRM app by New Endian. It works with all remote-enabled SM series transmitters to control audio level, frequency, transmission power, low frequency rolloff, LED, sleep and lock functions. 

6) Perhaps you want to get away from using a lav altogether, which can be challenging for interview or close dialogue situations. Parabolic mics, which are often used in sports broadcasting, can allow a safe distance without compromising safety or using a sometimes-unsightly boom in the shots. We realize that parabolic mics may have limited applications in many kinds of production work. However, in places where they can work, our Digital Hybrid and latest digital transmitters are an ideal match, with low noise floor, wide dynamic range and flat frequency response. 

A Word About UV Disinfection

Many of you have asked us about UV light for disinfection, and we haven’t tested any UV methods thoroughly enough to recommend them at this time. Our Service Department is presently testing options, and we will share our findings when they are available.

Learn more in our Wired List on disinfection. As always, consult the CDC Guidelines, which are updated as they evolve

Many thanks to AQTIS and the Canadian branch of IATSE, who provided some of the suggestions for this list and are allowing us to participate in the development of their working guidelines.

We want to hear about how you are adjusting to our new ways of working. Let us know at This email address is being protected from spambots. You need JavaScript enabled to view it., or start a discussion on our Facebook page.

Wire-Lists #25: 5 Best Practices and Tips for Creating An Online Worship Experience

Social Media WireLists25 300pxThe times we’re living in are requiring all of us to come up with new ways of doing things, particularly when it comes to group gatherings. If you are a pastor, a youth leader or one who handles the technology for your worship center, this extends to the holding of services and study groups. How can you lead your congregation remotely, particularly if you haven’t done it before? Facebook Live, YouTube and even your own website can offer you a way to reach out – we’ll leave the choice of platform up to you. In this list, we’ll discuss the five considerations for creating a remote worship experience, regardless of platform.

  1. Schedule and promote your content
    Think of your broadcast as an invitational event. Let your congregation know when and where to expect it, and how to participate. Forward-thinking communication and the need for connectiveness to community are huge right now, and doing this will help build anticipation and an audience for your service. Your website is the obvious place to start, but you can also publish a schedule in any mailings or emails you are doing, along with sending texts and publishing reminders on Facebook, Twitter and any social platform you may use.
  2. Choose a location
    Different situations call for different environments, so think about the needs of your congregation and what they will most connect with. Perhaps the location will be your desk in the church office. Maybe it will be in your own home. Or you might want to broadcast from your own altar or pulpit, or even somewhere in nature. Find a spot that is well-lighted, with the emphasis on you. Check your background for anything that might be distracting, and either remove it or position yourself accordingly to hide it.
  3. Sound
    Depending on how you choose to record and whether or not you are broadcasting live, there are two ways that you can approach sound:
    a) Mic through computer, using the computer’s camera – You will get the best sound if you use a headworn mic, like our HM172 and its accompanying C172 cable clip. The clip will cut down on noise created by the cable rubbing against your clothing. Another option is a directional, shotgun/stand mic attached to your computer, positioned behind your monitor, out of view, yet facing you. In both instances, you will want to treat the camera as if it were a person and speak to it, minimizing instances where you speak to either side.
    A note for live broadcasts: If you are broadcasting through your computer, turn off any notification sounds, such as those for email or Facebook. They otherwise appear randomly and are distracting. Be aware of anything in your environment that you can likewise turn off, minimize or schedule around, such as your computer’s fan, pets, household noise and neighborhood noise (leaf blowers, mowers).

    b) Externally, using a camera or GoPro – This option is for those who want more freedom of movement and are broadcasting in a wider area, such as a local pastor in our area did when he recorded his Easter Sunday sermon and prayers outside, in the field outside of his church. His technical person filmed him from an appropriate distance, using lenses and angles to convey proximity. To capture his sound, the pastor used an MTCR   and a lav mic. The tech person then married the visual and the sound in post-production and made the “service” available online for later viewing. We discuss a similar technique in Wire List #21. You can also use our SPDR to capture sound.
  4. Music
    Music is an integral part of any worship experience. When broadcasting remotely and using recorded sound, be mindful of copyrights to the music you are using. Churches often have license to use copyrighted music in their services, but at the time of this writing, this may not extend to online use. There are a variety of sources you can use that are royalty-free, and other options include having soloists appear on camera in a small-screen or including a Zoom-like choir with people performing from their own locations. We have also heard about pastors creating Spotify playlists that congregants can play on their own.
  5. Disinfection
    Whether you are using your own equipment or gear borrowed from others, disinfecting them after use is a smart practice. We discuss how to best do this in Wired List #20.

Broadcasting services online offer your worship centers many possibilities that will extend past this pandemic period, including expanding your outreach to different areas, providing on-demand Scripture studies, and making services available to the homebound or those living in remote areas. We learned a lot about online broadcasting when we developed our Wireless Side Chats and are happy to help you troubleshoot yours or develop a plan. Reach out to us through our Facebook group or This email address is being protected from spambots. You need JavaScript enabled to view it..

Wire-Lists #24: Making A Coaxial Dipole Antenna With 6 Items, In 8 Easy Steps

Social Media WireLists24 300pxYou’ve undoubtedly run into situations where you need to get your transmitter antenna away from the talent’s body, or where you could use a few more feet of reach for your receiver. We make & sell these coax antennas as the ACOAXTX here and there is also a BNC version available as well – the ACOAXBNC.

That said, if you’re handy and have done a little bit of work with wiring, you can make your own! In today’s list, we’ll explain how to make a coaxial dipole antenna, using a few readily available tools and a pre-made cable.

6 Things You Will Need:

  1. A piece of shrink tubing, at least a foot long. This will be used to give a finished look to the antenna.
  2. A pair of wire-cutters
  3. A cable with an SMA connector at one or both ends, like this cable from Fairview Microwave
  4. Heat gun or hair dryer
  5. An X-Acto knife, box cutter or razor blade
  6. Optional but helpful: color-coded caps to finish the end of the antenna

The 8 Steps:

  1. acoaxtxFold your cable in half and cut it at the halfway point. This will leave you with two cables with connectors on one end. Each cable now has an antenna on the cut end, so you can make two dipoles from this one cable.
  2. The higher the frequency, the shorter the antenna. To figure out how long your antenna should be, download and print out our antenna kit guide to use as a template, or use the measurements shown on the sheet’s table to find your desired block’s measurement. Lay the wire flat and measure outwards from the connector. Do not cut through the wire.
  3. At the point you measured to, lightly “score” the outside insulation (the rubber cord coating) without cutting into the shield or wire inside. What you want to do is separate the insulation/outer coating on the cable without completely cutting it off. You might find it easier to use an X-Acto/box cutter/razor blade to do this, rather than your wire-cutters, and nick the material a little bit at a time.
  4. Carefully pull the shielded wires out from the insulation by folding the wire at the spot that you cut, making a loop and pulling it out. The wire comes out easily once you have it started.
  5. Straighten out your shielded wire while bending the insulation to the side.
  6. Take your shrink tubing and carefully slide it over the insulation and the shielded wire. Slide it down to where the connector attaches, leaving the wire exposed at the end.
  7. Use the heat gun or the hair dryer to shrink the tubing. This conceals the insulation and gives your dipole a more professional appearance.
  8. Color coded caps can finish the end of the antenna and make it easy for you to distinguish from others you may have or make. It’s always good to keep a few on hand. We provide 10 different colors in our A8U kit. You can glue the cap on for more security.

This process creates a versatile dipole antenna that can now be used with any of our transmitters that have SMA Connectors. They’re great for hiding inside or pulling through costumes in those scenarios where you need slightly better transmission. This same procedure works to make receiver antennas (length is not an issue with those). If you keep the necessary items in your bag, you’ll be able to fashion any dipole you need, on the fly.
If you prefer to follow along with a visual, see the instructional video on our YouTube channel.

Wire-Lists #23: Phantom Power with M2Rs and Other Receivers, plus 6 Best Practices

Social Media WireLists23 300pxThe M2R was designed originally as a personal listening receiver, often called an “IEM pack” (in-ear monitors) and thus, we used a very high-quality headphone amp for the design. The downside is there is no protection from 48V phantom power when the M2R is used as a camera hop receiver and is connected to professional microphone inputs. We have seen several M2Rs (and occasionally other receivers) come into repair with damage from this issue. This List will discuss what phantom power is, why it’s important, and how you should work with it to get the best results and avoid damaging your equipment.

What is phantom power and why is it important?

Phantom power, commonly designated as +48V or P48, is a way of sending DC current through an XLR cable and was designed to power these devices without using external power supplies. The power is sent through the same cable that is carrying the audio signal and leverages the multiple wires in a balanced-XLR cable to provide voltage to mics that need it (condenser mics, which have active electronics and require a voltage for polarizing the microphone’s transducer element) without affecting those that do not (dynamic mics). You can plug either type of mic into a mixer that provides phantom power and the condenser mic will use that power, while the dynamic mic will ignore it. That is why it’s called phantom – it lurks in the background for mics that need it, is invisible to those that do not.

When did phantom power become an issue with Lectrosonics equipment?

With some of our earlier generation receivers (specifically CR-series, which some of you might still use), the signal from the microphone was cut off until the phantom power was removed. Some customers didn't realize what was happening, thought their units were failing and needlessly sent them in. So, we modified our circuitry to add a resistive series into our receiver design to protect against capacitive discharge, along with resistive bleeders to ground to reduce peak voltages and non-polar capacitors for protection against miswiring. This works, although we do lose one or two output stages when outputs are wired to 110VAC.

Can phantom power ever damage my equipment?

As mentioned, although most of our equipment has since been redesigned to account for phantom power, it is important to know how phantom power may negatively affect microphones in older units (and this covers rental equipment or other scenarios you might encounter onsite) before you decide to use it. For example, some multi-channel preamps can only apply phantom power across multiple channels.

The situations that could potentially cause phantom power to damage a microphone include:

  • Shorts. Electrical shorting will send the phantom power voltage up one audio conductor rather than both. Even a quick/brief short can cause the DC voltage to enter the wrong parts of the microphone and damage it.
  • Sending phantom power to an unbalanced microphone. Phantom power requires a balanced connection to work properly. If phantom power is forced through an unbalanced cable to an unbalanced microphone, the 48 volts on the audio cable may overload and damage the circuit. Examples of unbalanced microphones include DC-biased lavs and karaoke mics. Older ribbon microphones like those made by RCA can also be damaged by P48.
  • Power surges and brownouts. Power surges can overload the phantom power circuit. The spike in electrical current can fry certain wires or components within the circuit. Power conditioners are always a good idea, and although we don’t endorse one vendor over another, Furman is one most of you will be familiar with.

6 best practices when working with phantom power

Phantom power is not just a microphone phenomenon! There are some other devices like preamps and direct boxes that require a small amount of power to function, hence the presence of phantom power. These devices can often be powered by batteries, but many of them are designed to function using phantom power. Here are six best practices when working with phantom power:

  1. There is a warning in the M2R manual: “WARNING: If connecting this receiver to microphone inputs, such as in a camera hop arrangement, 48V phantom power MUST be turned off. Otherwise, damage to the receiver will occur.” We cannot stress the importance of reading your product manuals, especially for warnings of this nature.
  2. If you are unsure whether or not the device you are connecting with may have P48 present, use a phantom power blocking cable made specifically for this purpose. ACE Cables is one good source. If you choose to use this option, please be mindful of their disclaimer, which reads, “Phanton power block cables are fitted with passive components to protect from phantom power. An initial voltage spoke will occur when phantom power is turned on. Whenever possible, plug the XLR connnector in first, wait 5 seconds for the internal bleeder resistor to reduce voltage, then plug 3.5mm connector in. Components have an estimated 2,000 hour life. Periodically test cables with a voltage meter to ensure correct function.”
  3. If possible, only plug/unplug all mics when global phantom power is off. “Hot patching” (plugging-in and unplugging patch cables) is not advised while phantom power is engaged.
  4. Always mute your outputs/channels to avoid speaker- or headphone- (or ear)-damaging pops when plugging/unplugging mics with phantom power on or when turning phantom on/off.
  5. If you have to use a modern, balanced output ribbon mic with global phantom power, make sure it's plugged in before turning phantom on.
  6. Don't use a patch bay when using global phantom power, or make certain that phantom is deactivated when patching. Shorting 48V to ground is not a good idea for any mic.

Working with phantom power on the M2R or any of our receivers shouldn’t be a mystery. Still have questions? This email address is being protected from spambots. You need JavaScript enabled to view it..