by Tim Fok | 14th October 2016
Having dilemmas with the ARRI Alexa Mini audio? Are you struggling with having Line level input as your only audio option? The Beachtek DXA-Alexa is an audio module designed specifically for the Alexa Mini that converts dual XLR to Line level output. I was sent a pre-production unit to check out. Anyone who’s used an ARRI Alexa Mini intending on also recording sound will know its limitations: it has a single Lemo input on the front, and some gain settings buried in the menu. Not to worry, though. Wooden Camera do the cool little A-Box that converts that Lemo input into dual XLR. Sorted, right? Not so fast. You still need to feed it a Line level input, and here’s where many will struggle. Few audio sources provide this level output, which is why you usually have to go through another sound device, such as your soundperson’s mixer. Having a soundperson plus mixer may not always be an option, and that’s then your options are limited without your rig getting pretty hefty. Beachtek saw the need for a product to fill this need and recently announced the DXA-Alexa audio module, a sleek little box that receives XLR audio (mic level or providing phantom power) and outputs Line level via 5 pin XLR. Beachtek sent over a pre-production DXA-Alexa, which I put through its paces during a recent shoot abroad that required a single op camera and sound. Features of the DXA-Alexa The DXA-Alexa receives 2 channels of audio via standard 3 pin XLR. Both can be powered independently by 48v phantom power and both have a high and low gain switch (60db and 40db modes respectively). Neither channels have a metering display, but instead offer a tri-colour LED that works in the form of a traffic light system (green/amber/red) to meter audio. More on this later. There are three physical pots on the top of the module for adjusting the gain of each channel, as well as the volume of the monitoring output. The headphone output is a 3.5mm jack on the side, but there is also a 3.5mm jack for audio return from the camera. You can select whether you listen to the output or return via a switch. Additionally there’s a stereo and mono mode for choosing your headphones output options. Lastly, it offers a 3.5mm unbalanced auxiliary stereo out which I unfortunately didn’t have time to test this. Power is received by 2 pin lemo that has a voltage range of 11-18. Physical Features The module is well built, and is clad in a carbon-fibre-look to match the aesthetics of the Alexa Mini. It weighs 374g (0.89lbs). Full spec card here. All buttons and knobs have a satisfying feel to them, the power button recesses nicely and the pots on top have a half click resistance to them. The gain switches feel solid too. Connectivity The DXA-Alexa comes with no cables, so you must spec it for power and output yourself. The 11-18V range on the power input is useful, placing a standard V-lock battery system right in the middle. It means a straight 2-pin Lemo to D-tap will get you going. I bought a Hawk-woods LA-69A, and here’s a US non right-angle equivalent. The thin and slinky cable with a right angle connector provides a nice setup, as this way your cables will pop out of the dumb side of the camera, which is why the right-angle connector was important. The next consideration is audio output from the module to the camera. Wooden Camera has made a specific cable from 5-pin XLR to Alexa lemo. Unfortunately, this wasn’t available for my trip, so I picked up an off-the-shelf 5-pin XLR to dual 3-pin XLR tail, then went through a Wooden Camera A-Box to get the XLRs into lemo for the camera body. Both will do the job, but the former is a more concise way of doing it. Mounting It The Beachtek DXA-Alexa has three ¼” 20 threads on the bottom for mounting only. I found the best way of adding it to the Alexa Mini rig without things getting too bulky was to simply thread a 15mm mount on the bottom, and stack the module between the v-lock plate and the camera body. The rig becomes a little longer, but I felt this was more streamlined that side or top mounting. The included cradle makes use of two of the threads on the bottom. It gives you a couple of 3/8” screws on the side, as well a few ¼” 20 threads on the same side and one on the bottom. Additionally, on the opposite side is an array of smaller threads that adhere to the quad pin array that ARRI uses on the top and bottom of the camera. This means you can use the cradle with any existing ARRI accessories, mounting it between your camera body and handle as pictured, for example. Operation The Beachtek DXA-Alexa works exactly as one would hope. At first glance, you may ponder over the lack of metering displays and primitive traffic light system for audio levels. However, the camera itself displays audio level info, so you won’t miss anything more substantial in terms of on-board meters. To set it up you simply send a tone through the Beachtek DXA-Alexa (or consistent audio level if you don’t have access to a tone generator) set the gain level in the camera menu to your desired level (I went with a gain level that provided -18db on the meters), and you’re set. To then make any further level tweaks you then adjust the pots on the module itself. I found that I was using the least amount of gain from the camera itself by doing it this way, but as a result you require more gain from the Beachtek DXA-Alexa, and often the LED meter reaches red. You could counter this red light by increasing the level of gain in camera and reducing the level on the Beachtek module. However, I trust the amplifiers on a dedicated audio device more than those on a camera that are usually added as an afterthought, so I didn’t worry too much about seeing a few red blinks. The tri-colour LED scales operates at: Green -40dBu to 16dBu Yellow -16dBu to +4dBu Red Over +4dBu Summary I feel the DXA-Alexa is a must-have accessory for those who regularly record sound on their Alexa Mini and work without a soundperson. Could it be smaller? Perhaps. Half the depth with outputs and pots on opposite ends could be nice, a form factor that would have me consider a top mounted option far more seriously. The size of XLR ports is restricting here, substantially smaller would require specific breakout cables that can be less ideal. Could it be cheaper? Only Beachtek could tell you, but it does seem like the typical ARRI tax applies here. If you are looking for a cheaper option, you could consider the Beachtek DXA-SLR. This is a similar device originally designed to sit between your audio kit and DSLR. However, this doesn’t provide a true Line level (-26dBu at 0db on the VU meter, I’m told), so it would involve boosting the gain in-camera, and thus compromising the signal-to-noise ratio. It also can only be powered via 9v batteries, and would require a ¼” jack to lemo breakout (which doesn’t exist, to my knowledge) so generally a less than ideal system for the Alexa Mini. It’s a shame ARRI never made further efforts to offer more comprehensive audio solutions for the Alexa Mini. I’ve read it was never the intention to include anything at all, but with spare space on one of the boards they thought why not lob something in there for good measure. True or not, we’re left with a hurdle to jump in getting Mic level to Line level in a concise way, and I feel the Beachtek DXA-Alexa does a pretty good job of doing that.Read more
by Tim Fok | 9th July 2014
Just bought a GH4 or A7S? Missing those lovely audio features that large sensor camcorders brought back? Check out the DXA-SLR ULTRA, Beachteks latest audio module that offers professional audio features via XLR and 1/4″ jack inputs. The DSLR revolution was both fantastic and problematic. It brought us fantastic image quality (for its time) but created a whole host of issues with audio. The latter was arguably one of the main draws of large sensor camcorders. Despite the industry’s immense advancements with camera technology, we find ourselves in a similar position to that of a few years ago. There’s been a surge in popularity with mirrorless systems (thanks to two specific cameras), bringing us some fantastic features and improvements in image quality (compared to most DSLRs), yet we’re back to square one with poor on-board audio. (Having said that, the preamps on the A7S are much better than on Canon DSLR, as Johnnie discovered on his recent review of the camera.) Manufacturers have listened and learned from last time, both the GH4 and the A7S have their respective audio modules that provide greater audio options, yet both are expensive, and the GH4 YAGH interface specifically has a very poor form factor and tricky power options. The DXA-SLR ULTRA is a third party solution for audio, which will no doubt be popular with owners of the new GH4 and A7S cameras, as well as many other XLR-lacking DSLR and mirrorless systems. The DXA-SLR ULTRA is designed to sit under your camera (much like a battery grip) and works inline with the 3.5mm input on your camera and professional audio equipment such as shot gun mics, wireless kits and mixers. It negates the need to record audio separately, offering two audio inputs that double up as both XLR and 1/4″ jack. Each channel is independently adjustable, and along with the monitor volume is controllable via a large analog knob. Other features include independent limiters for each channel, phantom power, low-noise preamplifiers for better audio recording and gain & mic/line switches for greater versatility with various audio formats. Beachtek has released a host of similar devices over the years, a brand new feature of the DXA-SLR ULTRA is the detachable 15mm rod mount. The rods supplied with the device are threaded on both ends, so providing Beachtek haven’t been obstructive we should be able to use any threaded 15mm rod accessories. Whilst this won’t fix the issue of poor inbuilt pre-amps in your XLR-lacking camera, it will give me much greater control over the audio going in, as well as proper audio monitoring both coming into the device, and being recorded to the camera. Here’s a list of the key feature of the DXA-SLR ULTRA Detachable 15mm rod support base. Includes two threaded 3″ rods 3.5mm input to loop back from camera for playback monitoring Built-in headphone amplifier with volume control and 3.5 mm phone jack Switchable 12V/OFF/48V phantom power for both channels Built-in limiters prevent distortion from overly hot inputs High/low gain setting for each channel and MIC/LINE switches Easily replaceable 9-volt battery and low battery indicator Transformer-balanced inputs for isolation and enhanced circuit protection Sturdy die-cast aluminum enclosureRead more
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