TA-5 (“5” for 5 pins) mini-XLR female connectors are the standard lavalier and headset microphone termination for most Lectrosonics transmitters made in the past 30 years. Undoubtedly, if you’ve been at this for any length of time, you’ve experienced a connector getting stuck. And if that happens, your only option is to sacrifice your lav by cutting the cord to dislodge it. Or is it?
According to Glen, there is no need to destroy the cable or connector. Before we explain why, you may want to review our Support article, which explains the inner workings of TA-5 connectors, so you understand what we’re talking about.
The reason connectors get stuck is because, more than likely, something inside the connector is not letting the push button push down on the release hooks. Although uncommon, it is most likely to happen when the insert is not flush with the front end of the connector (pushed back into the connector by .125”+) which will prevent the hooks from being released. It can also happen if the connector has been forcibly twisted to the point that the hooks are binding against the connector housing, which could happen if the back of the connector is tightened by twisting it while inserted in the device.
Two Simple Steps To Remedy The Issue:
Unscrew the back of the connector and pull out the cable assembly (partially pulling it out is sufficient). This ensures that nothing is interfering with the push button’s movement.
Reassemble by pushing the assembly back in all the way and tighten the back. Before pushing it back in, push the button and make sure the hooks depress and that the insert is flush with the end. As stated, it takes at least a .125” recess to interfere with the push button.
Doing this effectively remedies the issue. Barring any additional working mishaps, your lav will likely work as expected for years to come.
One Last Word:
Sometimes, when a large diameter wire is used (such as line input cables larger than the usual diameter wire of a lav mic) an internal bushing must be removed to make the cable. Part of the reason that bushing is used is to keep the insert all the way to the front. The absence of the bushing must be compensated for (usually with added tubing) or the insert might be pushed back into the connector, thus interfering with the push button’s movement.
With many of us getting back to work, "covid compliance" requires that all staff working on a production to be distanced. Many of you have shared your creative solutions and new working protocols with us. For example, we're hearing that some production sets are becoming their own "quarantine facilities," where staff live and work dorm-style in a sanitized area onsite, with no one new coming in or out until production is over. Some directors will also have only necessary talent on set, and locate the sound personnel and production staff in other rooms or parts of the facility. This need to distance is very much a "figure it out as you go along" world right now.
In our last list, we discussed how to do a solo walk test on set. We also discussed the custom tuning range capabilities of Wireless Designer, which allow you to preplan your set-up, to minimize your contact with the set. So, what do you do when you have to plan to work at a distance from the talent? Enter Dante.
Dante is the protocol for transferring audio over the network cable. It is "plug and play" and is so reliable that many companies, including Lectrosonics, have made it a standard built into their equipment. In our case, D2 and M2T are both Dante systems. In the past, if the engineer had to be far from the talent, the only solution was either to run audio cable - one line for each channel or a multipair snake – or, to run long antenna lines. As you can imagine in a standard production environment, this can be unwieldy and unsafe with cables snaked everywhere, but also potentially unreliable, depending on how far you had to bridge. If you had to run a long length of line, say, to an antenna, the signal suffered as well. The main advantage to Dante is that you can send as many as 500 channels (audio and video) over a single fiberoptic cable. Depending on the type of cable (CAT 5e or greater) you’re using, you can achieve distances of 300+ feet and even more with the help of a booster. Many sets and professional buildings have network ports built into the walls that you can easily plug into, using the building’s network. The building’s or set’s IT personnel can advise you of the IP address and access credentials.
Like our Wireless Designer software, Dante has its own Network Controller that allows you to monitor the devices connected to it:
An example of how you can use Dante would be:
Arrive on set with a 300-foot length of Cat5e, Cat 6 or fiber cable (converter boxes required for fiber). That length will cover most situations. Use a rack case for your equipment and place it in the same general area as the talent.
Plug into the available network.
Use Wireless Designer (which can map not only Lectro equipment, but can include units from other vendors via custom channels) to set up your system, and the Dante interface to see all of your connected devices and set your outputs and links
The Dante network can then be the bridge between your department and others on set via IFBs or Duet IEMs. This will enable you to distance while at the same time delivering good sound to all the stakeholders.
Did you know that Wireless Designer comes with a feature – The Walk Test Recorder - that will allow you to do a walk test all by yourself, with no help at all? It’s a very useful tool, especially for those solo engineers that don’t have a second set of hands and feet to help them with a set up in a new venue, or when their environment limits the number of people that can be in the area at a given time. It’s a way to test RF signal strength and antenna switching, as well as squelching and recording audio.
Even experienced users of Wireless Designer might not know this feature exists, because it is somewhat hidden. In order to see the Walk Test tab at the top of the screen, you have to have a receiver connected and selected from the device list on the left of the screen. You otherwise won’t see it as an option or a feature anywhere else in the system. This screencap shows you where.
Connect the Receiver (D2, Venue or other). Once you do that, you will see “Walk Test” as a tab at the top.
Create a new file and tell the system where to save it.
From within Wireless Designer, choose which RF channel you are evaluating. Hit record, then walk the transmitter around.
This will essentially allow you to “soundcheck yourself.” You will be able to, for example, ensure that you have a good signal strength from far ends of the stage. If you don’t have good sound, you can review the recording report and troubleshoot where your issues are and address that specific area, without having to have multiple people sweep the area to find them – a real bonus in our current environment.
The only other thing to keep in mind with this exercise is that the audio is not automatically routed through the USB connection from the receiver. You have to connect the audio output from the receiver or mixer to the computer’s line input or into an audio interface connected to the computer.
Once you’ve recorded the file you can review it to look for problem areas at your location, then make adjustments to your antenna location, transmitter power, or other ways of improving reception before you have to “roll a take.”
Our newest version of Wireless Designer (version 2.0.25) for both Mac and PC comes with some great new features that should save you time, give you new control, plus added convenience that you might not have thought possible. Let’s dive in:
1) Offline Mode
The new Wireless Designer has an "offline mode" where you don't need to be connected to a system in order to start configuring. You can design all of your set-ups ahead of time. Here’s how. Click on any of the images to make larger:
With connected devices, chick on File, then New. Right click on Session, then Add Frame. You can add any of the devices shown.
To add channels, right click on any of the Channel Controls in the lefthand grid, then add a channel (s). You can also add a channel by right clicking anywhere in the grey area of the graph as shown below.
You can also Right click into any of the connected device areas to configure that device. Once you do that...
...switch to frequency coordination, then click the new Custom Range tab.
Unless you press "Deploy to System," this is just a sandbox area that doesn’t have to be stored, and you can try out different options without being locked into them. If you switch between tabs or push “Deploy,” you will get a 3rd box that comes up to ask you to save/apply settings.
2) Frequency Coordination Options
Under “Frequency Coordination,” you also have coordination options that allow you to type values in to coordinate with spacing. There are defaults that we pre-programmed to be universal in most cases. If you change the defaults to closer than recommended, you see red type that indicates that the range might not be optimal. You can override this if you are sure that you want to use your ranges:
It will alert you if there are frequencies that may be too close by displaying caution triangles. You can still proceed, but if you want to adjust this range, you can do so by dragging the slider bars until the alert disappears:
If you’ve tuned to range that will not work, “Alerts Detected” will change to “Warning” and will be in red.
3) Custom Channels
Once you add channels, you can edit all of the channel properties except the block/band.
If you right click or double click, you get a properties screen. You'll see, under Frequency Controls, "Custom Tuning Range." The “Use Custom Range” checkbox is blank by default. If you check this, you can edit the start and ending frequencies for that channel. The start and end will be limited to the band you have selected. This also comes into play when you are running the automatic frequency coordination.
If you click the Transmitter tab, you will see a "Narrowband TX" option. If you check this, you will get a dropdown. This limits your tuning range to a Narrowband block that you choose. This setting takes priority over the settings you set in Custom Ranges.
You can also access this option from the Frequency Coordination tab, which is a new option. You can manually specify the ranges or carrier frequency in this section as well.
The most common use for this feature would be when you are using a wideband receiver. Configuring through this feature will allow you to use different parts of the spectrum for different parts of your system, an important feature for optimizing your band planning strategy.
4) Importing Scan Data From File
Within the Frequency Coordination screen, there is a new setting called "Import Scan Data From File”. This is handy when you know ahead of time which units will occupy which bands/blocks.
In addition to being able to use stored scan data, the system now also supports different file types (SPA, CSV, Sdb2 or SDF). An online source for RF scans is https://taajuus.info/scan-database
5) Enhanced Reporting
This feature will allow you to save a graphic interpretation of your settings that you can then share with other sound personnel, front of house or others involved in your project. Use the Generate Report button to obtain:
The result will give a report of the devices on the system and will look like this:
Be sure to check out the Revision History and Online Help section on our Wireless Designer pages to see all of the features that have been added. While you’re there, make sure that you have the latest firmware revision.
In our recent Facebook poll, many of you expressed interest in learning how to set up transmitter/receivers with recorders in an on-the-job scenario. Last week, we heard from Bal Rayat and Bruner Dyer. This week, we hear from Chris Howland and Steve Morantz.
Chris Howland is the founder of the LA Sound Mixers Group, a long-time Lectrosonics user and has worked on countless film and TV projects. Chris reports that “most of my gain staging is done by feel and the anticipation of the unknown.” The following numbers are his starting points:
From a VR Field Venue to a Sound Devices 688
Line level input settings (normal voice and louder performances)
Field Venue output +08
Sound Devices 688 input trim at LINE level and -8db for unity gain. Will sometimes push to 0 or 2db for soft speakers.
Mic level input settings
Used when I have a “mumble actor” or soft speaker. This allows me to add gain on the receiver side if it is needed so I don’t have to push the mic pre’s so high that they are out of proportion.
Field venue output -15
Sound Devices 688 input trim at MIC LEVEL and 26db will have to reference tone sitting at 8db on the 688’s meter. This allows me plenty of head room for soft speakers
UCR411a receiver to a Sound Devices 688
Line level input settings
UCR411a output set to +5
Sound Devices 688 input trim set to LINE LEVEL and dialed in to -6db for unity gain. (will sometimes push to 2db for some speakers)
Mic level input settings
UCR411a output set to -33
Sound Devices 688 input trim set to MIC LEVEL and dialed in to 34db for unity gain. I will sometimes push the mic pre to 42db for soft speakers and if needed, the last resort is to take the receiver from -33 to -25.
Transmitter levels (with a Sanken COS11 black band standard sensitivity lav mic)
SMWB Transmitter Level set to 22 to start. Would need to be higher for softer voices.
SMV Transmitter Level set to 18 to start. Would need to be higher for softer voices.
Boom transmitter (HMa) with a Sennheiser MKH50 microphone level at 35 and the receiver and Sound Devices 688 is always set to line level receiving numbers, because we always have access to that transmitter for gain adjustments whereas, with actor lavs, access is not always guaranteed or convenient.
Steve Morantz has worked extensively on TV productions – including Parks & Recreation, Entourage, Dead to Me, Just Add Magic and many others. Here, he shares his settings for the variety of mics and situations that he works with:
I run my receivers at line level as high as they go, +8 on the rack receivers and +5 on the 411 series. I have a Sound Devices SL-6 with Lectrosonics SRCs, and the default setting for that is -6. So for that system only, I use that setting.
Lav mics have different gain and padding. I use DPA 4061, 4071 and 6061, which are 10 DB lower than the DPA 6060s, and Sanken COS11 lav mics. For the Sanken and 6060, I start my gain on the mic pack at 20 and adjust accordingly. On the 4061, 4071 and 6061, I start at 26 and adjust as well.
I just finished up Season 2 of the TV show Mayans M.C., where we would put a boom on the biscuit (vehicle with camera arm) and record the motorcycle noise. For that, I would put the gain down all the way to 0 on the transmitter for the plug-ons.
Cardioid and Shotgun Mics:
For cardioid and shotgun mics, I run the gain on the transmitter usually around 28 and again, depending on the environment, I can adjust down to 17 or as high as 34.
In our recent Facebook poll, many of you expressed interest in learning how to set up transmitter/receivers with recorders in an on-the-job scenario. We reached out to a few sound pros in the know, and this list is Part 1 of a multi-part series around how other users approach this exercise.
First, we’ll hear from Bal Rayat.
Bal is a UK-based Sound Recordist and long-time Lectrosonics user:
How he sets up receivers (SRB and SRC):
“Always set the receivers to line level (as that what Lectrosonics are natively) at +0dBu. I engage the tone on the receiver and set the level on the mixer so that the level is slightly over 0dBu.”
How he sets up his transmitters (SM ):
“The transmitters are a little hit and miss, but I will mic someone up and then ask them to speak as loud as possible. Generally, people feel a little shy and won’t give you their full volume, so I set the gain on the transmitter and then back it off a couple of notches. What I’m looking for is full modulation of the transmitter so both LEDs on the transmitter light up during normal conversation. When the person speaks at peak volume, I want to see both the -20 and -10 LEDs lighting up, with occasional -20 flickering red. I rarely have to alter the level as the limiters on the SM series are so robust. The settings on SMs and SRBs are the same for mixer and talent.”
Camera Hop Settings:
“I’ve recently moved over to the DCHT for my hop duties. I take AES out of my mixer and straight into the DCHT. I use a M2R on cameras and they can be set in two ways. Most cameras will take an unbalanced line-level signal so the M2R volume level is set to 80 and limiter gain set to +15, with the threshold set to “off”.
For cameras that can only take mic level I set the M2R volume at 35 and limiter gain to zero, again with the threshold set to Off. For both types of cameras, I set my M2R volume taper to “Log”.
Now when using SM and SRB combo for hops, I do the following. I set my mixer output level to -10 (consumer line level). Set transmitter gain to 20-23 and set SRB to +5. That combo has always worked for me.”
Next up is Bruner Dyer, who has worked as a Sound Mixer and Engineer for reality TV and sports:
How he sets up receivers:
“From the receiver to the recorder, I set the analog output of the receiver at the highest line-level reference level (+05 in the case of Lectrosonics) going into the analog line-level input of the Sound Devices 833 (or any normal professional recorder).This avoids having to reamplify the signal in the recorder that was already amplified in the mic preamp of the transmitter. The loud line-level signal,as opposed to running the output of the receiver at the much lower mic level and using the mic level input of the recorder, will help my audio blow past any unwanted noise that may be amplified by the recorder’s mic preamp when having to reamplify the signal. When using an SL6, it works best at -6 on the output of the Lectrosonics receiver.Once you have a rule, you have to be ready to break it.Situations vary.”
How he sets up his transmitters:
“I amplify the microphone at the preamp in the transmitter.Basically, I set the gain as high as I can, while avoiding hitting the limiter too hard, thus coloring the sound too much.I have to plan for the loudest sounds I will encounter before I can practically adjust the gain again on the transmitter to meet a new situation.” Our Wire-List on Audio Gain goes into additional specifics of what Bruner mentions.
To his point about breaking rules, Bruner adds that he has a friend with a different approach to syncing the receiver to a Sound Devices recorder. “One friend runs his output gain at -12 on the receiver and uses the mic level input on the recorder.He ends up running the gain pretty low on the Sound Devices to compensate for the hot signal coming in.I think he can really crank up the gain this way.It works for him. “
One of the most misunderstood settings on a wireless audio transmitter is the audio input gain, and we’ll explain some basics on how to set yours to get the results that you need. It’s easier than you think!
Most Lectrosonics transmitters allow variable gain in 1dB steps over a range of 44dB. The SSM offers an additional 7dB of attenuation at the bottom end of the gain range, to use with high output lav mics or with loud singers (typical in musical theater situations). Our HM and HMa plug-ons give you an additional 10db of gain at the top end to use with low sensitivity dynamic mics. Why do we offer this level of fine control? To optimize the signal to noise ratio – but we’ll get to that in a minute.
Three factors that affect how you set your gain are:
How loud is the sound source? Are you recording spoken word? Singing? Instruments? How much variance in volume is there? Highs and lows? Consistent?
How far is the sound source from the mic? And, is the sound being transmitted through a lav? A handheld? A parabolic? You need to look at distance and the type of mic you’re using.
How sensitive is the mic that you're using? To continue the above, are you using a condenser mic? Or even an old ribbon mic? Most lav mic manufacturers offer models with the same capsule but different sensitivity levels.
Optimizing Signal to Noise Ratio
Signal to noise is the ratio of desired signal to the noise in the system. Our Tech Note 1016 discusses this concept in detail. All wireless systems have noise - whether in the system (usually heard as a hiss) or riding along with the radio channel signal as mild interference (apparent as pops and crunches). You'll almost always hear the presence of channel noise if the mic is at the very edge of its range. To compensate for this, you'll want to turn up your audio gain on the transmitter enough so that you get a good signal to noise ratio (desired signal to noise floor). The way that you know you have a good ratio is by bumping up against the limiter in the transmitter so that the LED lights up - or what our techs call "tickling the red" on audio peaks. The limiter is a circuit that monitors the audio level and makes sure that it doesn’t distort or overmodulate the signal. On Lectro units, look for this by first checking your input levels, which show on the screen or via the bi-color LEDs. You would adjust the levels until you see the limiter indicator turn on briefly on peaks. The manual for your transmitter, as well as the card that ships with all units, will explain how to set it:
All units have a -10 and -20 LED. If you get a faint signal, the LEDs are green. Once you bump the limiter, you will see the -20 LED turn red.
The -20 LED is key to setting gain on Lectrosonics transmitters. Too low of a gain setting with any FM-based wireless system (including our Digital Hybrid Wireless® series) can affect your range in that your sound source can get lost in the noise floor. Too high of a gain setting will result in excessive limiting and possibly distortion, which is just as undesirable.
The loudest part of what you are recording should hit the peak while providing a good amount of headroom. Headroom is the difference between the loudest sound and 0dB (which is where sound clips or gets distorted). 30dB is a general starting point for the conversational speaking voice. Lectrosonics systems also have squelch based on pilot tones and SINAD (signal to noise and distortion) built in. If the SINAD is too low, the receiver will cut off the audio signal to prevent drop outs, thus shortening your range.
For those of you who use SMB or SMWB transmitters, customer Matt Price from SoundRolling.com put an excellent video on YouTube with basic gain setting suggestions.
One of our most popular videos covers this topic as well, and the bonus is a roadrunner cameo!
Our video with Phil Sousson reviews settings for the LMb and LT, particularly for bass and guitar, but useful for other applications as well
Troubleshooting 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):
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?
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?
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 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:
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:
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
We have several other product-specific videos on understanding gain. Just search “gain” on our YouTube channel.
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:
Attach a microphone and set your gain with a voice test until you have full modulation on the transmitter;
Monitor the output from the receiver with the audio at a comfortable listening level;
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;
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.
We'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!
In today’s list, we’ll discuss improving Signal to Noise ratios using PF25 filters.
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.
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.
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.
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.
Preparation 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.
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.