Still hard-lining video in 2024?

Three top contenders for wireless video on sound carts!

It’s been many years now since most sound mixers ran a duplex cable for boom and it’s standard practice that every talent with dialogue wear a wireless transmitter and has been so for at least the last twenty years. In addition, dozens of comteks are distributed daily including multiple IFB’s and our crew coms. Then we can have multiple camera hops, a VOG, wireless speaker for playback and wireless bluetooth TC devices with all the varying apps. We are undoubtedly a wireless powerhouse on a film set. So what’s the deal with wireless video feeds? Why have so many of us remained hard lined while fewer have taken the leap? I think the answer to that question varies for each mixer but if you are considering wrapping that cable for good in 2024 you’ll want to consider your options carefully in the highly congested and complex RF landscape we call a film set.

“The good news is the offerings for wireless video transmission have evolved significantly over just the last few years and we have some strong contenders!

However what has been slower to evolve is the amount of RF spectrum available authorized for use and the proper coordination of these frequencies amongst crew on a film set. Most wireless video systems available today utilize the unlicensed 2.4 Ghz band and the 5/6Ghz U-NII band or “Unlicensed National Information Infrastructure” Having the goal of finding the right system for my needs I reached out to and had some great conversations with experienced film veteran and DIT Joe Dare in LA and a video assist Jay Adkins here in Atlanta. I’ve worked with both of these guys and they know their stuff especially when it comes to the nuances of video transmission and I received some excellent input. Through these conversations and some additional technical research I’ve narrowed down my choices to three specific systems which are each contenders for my workflow as a production sound mixer that I believe are well suited for a sound cart.

The three products we’ll be exploring are the Accsoon Cineview SE currently priced at $519 US, the Hollyland Cosmo C1 at $899 US and the Teradek Bolt 6 LT 750 at $2790.

Recording Dialogue In Cars Annoucement!

Before we get into the details of each system let’s first explore what each of them have in common that make them suitable for a sound cart. These commonalities, in addition to their budget price points were the determining factors for my decision when narrowing them down. They are all small and lightweight coming in at under 250grams, can transmit at least 1080p with a minimum of 750’ LOS range and offer both SDI/HDMI inputs and outputs. All three are compatible with 12v DC power and you also have the ability to mount Sony L series batteries directly to the transmitter/receiver for convenient on the go powering. And finally they all have mounting options using various quarter twenty accessories. So one could easily mount a transmitter on a video assist cart with power and have them send a split feed allowing you to mount one receiver on your sound cart providing you have a monitor that’s large enough to view a split screen. Now that we know the similarities let’s dive into some of the differences surrounding RF frequency transmission schemes, RF propagation capabilities, LOS max transmission distance and latency.

Accsoon CineView SE Multispectrum Wireless Video TX/RX

The first one we’ll discuss is the Accsoon CineView SE which is the most economical of the three that I'm considering at $519 US. This budget friendly version caught my attention first because this is the replacement to the recently discontinued and larger form factored CineEye 2S Pro that I saw another mixer using who was doing splinter units on my recent show. When asking him about his experience with the system he’s said he’s had very good results.  The CineView SE boasts an impressive 1200’ line of sight range and one thing of particular interest to me is that it transmits the same image on both 2.4GHz and 5GHz frequencies at the same time. The receiver then intelligently identifies interference as it combines the two signals together as needed into a complete single stream. This dual band transmission is compelling to me especially because although the 2.4GHz band is crowded it also propagates through solid surfaces more efficiently than 5 GHz. In comparison most Teradeks utilize the DFS U-NII 5GHz channels so having the additional 2.4GHz frequency could hypothetically serve as an advantage to help punch through the noise a bit. Speaking of punch It’s important to know that the propagation of the antennas are horizontally polarized, so placement of the transmitter on the same height and vertical plane will be key to maximize transmission robustness. It has very low power consumption and will run on a single NP-F970 battery which can last up to 12 hours. Additionally, it can be powered via the DC input port (7.4V~16.8V) as well as a USB-C power source (5V). One common complaint I did hear about this system from users is latency.   The specs advertise it as low as 50ms but in reality it often performs closer to 70-150ms in some instances depending upon network congestion. For most focus pullers I know this would be unacceptable but for a mixer it’s tuff to say because some say they don't care cause they just need frame lines, others will say it takes them out of the mix. It all comes down to preference here for each sound mixer and opinions will vary. One final note and really nice feature of the CineView SE is that is offers simultaneous wireless transmission for up to four mobile devices via the Accsoon app. So your boom op could check out frames on set with their phone or a mounted tablet!

Hollyland Cosmo C1 TX/RX

The next video transmission system we’ll discuss is the Holland Cosmo C1 which is currently at $899 US which caught my eye because it seems to be designed to perform better in more complex RF environments. According to the manufacture specs the difference is that it utilizes a technology called HEVO with adaptive frequency hopping (AFH) and seamless retransmitting technology which brings superior reliability, boosted signal strength, and superior anti-interference performance reducing drop outs. It also boasts a 1,000ft line-of-sight range. It’s also worth noting that it comes with a hard shell case which store your AC power supply and the four standard horizontally polarized antennas plus 2 vertically polarized mushroom antennas allowing simultaneous propagation on multiple planes which should allow more flexibility as far as placement when it comes to height and orientation in comparison to the fixed antenna design of the CineView SE. The Cosmo C1 transmitter also has an additional SDI direct output on the transmitter as well which could come in handy for your video assist or DIT freeing up a needed port. On the flip side I can’t help but think that this HEVO/AHF frequency system sounds very similar to the Teradeks DFS or dynamic frequency hopping transmission schemes in the same 5GHz range. I fear it could be viewed as the red headed step child by the camera department and blamed for any RF inefficiencies they may be experiencing forcing you to go hard lined just to get along. In addition it also has less frequency real estate options when it compared to the simultaneous 2.4/5GHz transmission of the CineView SE. Some final notes on the Cosmo C1 is that it does has a higher transmission power output with a maximum of 22 dBm versus the 17dBm of the CineView SE’s. Combine that extra flexibility of the diversified polarized antennas of the Cosmo C1 and it becomes quite the compelling contender. Also the Cosmo C1 has an advertised ultra low latency of 40ms which is 10ms under the advertised specs of the CineView SE. But once again user reviews show that it’s more in the target of 60-140ms. We’ll learn more about why this variable latency exists on both the CineView SE and Cosmo C1 when looking at our our third and final contender. One final note is that the Cosmo C1 is the only unit of the three that has a fan built into the transmitter/receiver versus the silent fanless design of the the Bolt 6K LT 750 and CineView SE.

​One of the most compelling options which comes in at a base price of $2790 US is the Teradek Bolt 6 LT 750. Right out of the gate one of the biggest benefits of the Teradek system is its zero latency transmission. It accomplishes this with it’s proprietary Amimon’s chipset which has a frame-based transmission scheme which clearly sets itself apart from both the Cineview SE & Cosmos which both will ad noticeable latency to the system. Next the frequency transmission is unique amongst the three as it uses the recently FCC approved next-gen 6GHz wireless connectivity plus full 5GHz cross compatibility across all Bolt 4K Series devices giving you more flexibility as far as spectrum real estate and creative workflows allowing you to collaborate with the camera department for varying setups. Interestingly the RF transmission power output is very similar to the Cosmos C1 being right under at 21dBm on the Bolt 6 LT 750. If your workflow is like most mixers whereas you get your feed from either video assist or DIT we should always be within about a 100' so it’s 750’ line of sight advertised range shouldn’t be a problem. Also the chasis of the Bolt 6K has been completely redesigned to allow more efficient cooling and the fans are now up to fifty percent quieter. I’ve been outside of set next to plenty of focus pullers who have Bolt 4k receivers mounted on their monitors and this has never been a problem for me. Also it’s worth noting that the Teradek Bolt 6 LT 750 has a silent fanless design for both the transmitter and receiver for absolute silent operation. For power it has a 6-24V DC power input that works with your 12V cart power and with this unit you’ll need to purchase a mountable sled that will allow you to use your Sony L type batts for $150 US each versus the the other two which are included with the system. In addition to coming with a nice hard shell case and some mounting accessories if you want to diversity your antenna polarizations like the Cosmo C1 you’ll need to purchase their H style antennas which come in a set of four for an additional $349 US.

In conclusion it’s worth mentioning that all three have a host of additional and varied features that are worth checking out. After carefully considering all three contenders I’ve decided to adopt the Teradek Bolt 6 LT 750 into my workflow. I mostly work on larger scale film sets with very complex RF landscapes. I need the utmost in RF robustness and spectrum flexibility in wireless performance. When it comes to price, how I see it is for less than the price of most professional audio wireless system per channel, I can utitlize what has been proven as the gold standard on film sets. One of the biggest challenges for me when using any wireless on a film set is never really range, it always comes down to signal robustness within a reasonable operating range. I also believe the Teradek will allow more collaboration with the camera department and is less likely to cause interference since it utilizes the same DFS or fixed frequency flexibilty which can be worked out in advance with camera. They are familiar with the system and can be specific about settings that they’ll want you to use for the best possible coordination which I know I also want with all things audio on my film set! This all being said, if I was working on docs, commercials or corporate with smaller crews primarily it may be worth the budget savings to go with the Cosmo C1 or CineView SE and some mixers have already implemented these systems on larger scale sets and are saying good things about their experiences! Which ever way someone decides to go the clear winner we can all agree on is it’s more beneficial to not be cabled saving you time and frustration with the ability to go wireless for video in 2024. We just need to trudge forward carefully, as coordination and collaboration with all departments will be key. Hopefully once and for all I can retire that heavy multi part hard line video cable and give my department more time to focus on more important tasks that help us get the best tracks possible!