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RadoStefanov

Zaxcom RX12 review and comparison

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I spend a week with the Zaxcom RX12 + 3 modules last week and put it against my OneUnit micplexerII + 3 qrx200s over the weekend.
 
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Here are my findings summarized:
 
 
               Size and ergonomic design
Bigger then Nomad so harder to bag in a nomad setup.
The modules handles stick out even further making it even bigger.
Heavier.
Fan is on the bottom making it unpractical to lay on the bottom of a bag.
It has Sma antennas instead of BNC which makes it harder and timely to swap between antenna systems.
RX12 AES is on the opposite side of Nomad AES
TA5 connectors instead of DB15.
The RX12 should have Zaxnet integrated for a few reasons: Users could use it with maxx or other third party recorders. And if QIFB is integrated the same way as QRX235 we would actually be able to see the transmitters gain which has been my major complaint about Nomad Zaxnet and IFB200.  I understand if no piece of gear was able to show an exact TRX gain but if the qrx235 can do it everything else should. Knowing the gain of the transmitters is very important to me. And I dont buy the idea that Zaxnet can not be put in to Maxx or RX12. I have removed QIFB from a QRX and I know how big it is...
Power switch is on the side the same way as Nomad power switch and you have to reach down the bag to access it. I prefer the Maxx power switch on the top. If maxx has it must be possible. I would actually pay to get the Maxx style power switch on my Nomod.
There is no Power Indicator on the screen leaving the user in the dark about how much battery is left. In the Era of SMBus Smart Batteries  I guess only sonosax are current with todays technology.
The RX12 power consummation is not to far away from 3 qrx200s with micplexer. It needs a little more juice and runs less time but it is not as bad as I expected. I tested it with Inspire-Energy 100Wh battery. Switching off modules will reduce power drain. I a few people asked me online if that is the case and it is.
Since there is only one kind of RX12 having the modules is not very practical to break down wireless between other setups. If there was an cheaper RX2 RX4 RX6 RX8 and RX10 it might make more sense. IMHO having bunch of QRXs is way more practical compared to 1 or 2 RX12s
               RF Performance.
All test were done with the sound cart outside and  test subject walking away and getting inside buildings walking between people and hiding behind a metal paint booth.
The RX12 measured RF noise even when the antennas are not connected. I have no idea way. Even if the Nomad is Off there is 39-42 units of noise.
As far as Single Mode and dual modethe RX12 performs "OK" with whip antennas and "GOOD" with external antenna away from the bag. As any other Zaxcom wireless the whips pick up noise from the receiver they are connected. I have expressed my opinion about  Zaxcom receivers and whip antennas on many occasions. Raising the antennas even few inches always improves reception. XR modulation  deals with noise a lot better then previous modulations but still “remoting” the antennas gives me a lot more range and peace of mind.
With Elevated Zaxcom sharkfins RX12 is comparable to OneUnit and  starts cutting off 10-15 yards before the OneUnit. I must confess since I designed the OneUnit and put the micplexer away from the qrxs inside the Nomad on top of the Mirror card my wireless performance have been a lot better and stable then before.
 
All things considered great Idea me and others have asked for but a product that feels a little rushed to the market without putting to much effort to make a perfect product.
Most downsides and limitations are manageable "dual mode needs to be retested" . Don't know if this is the case with the unit I was testing or all around issue. Maybe other users can share their dual mode experience
Thanks
 

 

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Thanks for the write-up Rado. I too wonder if the performance issues you're experiencing are limited to just your unit. I've seen other people post about the RX-12 and don't recall any of the issues you've mentioned.

I personally really like the concept of the RX-12 and the hot-swappable modules, but as you state, it becomes even more valuable if you have multiple units to swap the modules between with. RX-12 is a good solution for cart, or dropped bag, but I do think we need smaller versions too, like an RX-8 with 4 modules and an RX-4 with 2 modules (as I mentioned in the "Equipment Wishes for 2016" thread). Built-in RF and power distro is a must.

I agree that the I/O on the RX-12 is not as intuitive as it could be. I also think it should've had a DE-15 connector on the same side as the Nomad and Maxx. I also think that it should've included Dante. I don't mind the handles on the QRX212 modules, but I guess they could be made shorter or lower profile.

I would've also liked BNC connectors for the RF inputs on the RX-12 better, but I also would've liked it if the RX-12 could've powered active antennas too. Built-in Zaxnet would've also been awesome.

I guess at this points I'm just throwing wishes out in the air... haha

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Talking to other RX12 users they are saying that they don't notice the dual mode issue.

9 minutes ago, Jose Frias said:

I personally really like the concept of the RX-12 and the hot-swappable modules, but as you state, it becomes even more valuable if you have multiple units to swap the modules between with. RX-12 is a good solution for cart, or dropped bag, but I do think we need smaller versions too, like an RX-8 with 4 modules and an RX-4 with 2 modules (as I mentioned in the "Equipment Wishes for 2016" thread). Built-in RF and power distro is a must.

 

A lot of people wish for RX6 for nomad and RX4 for Maxx.

In my opinion even a single shell one module  RX2 might help make the RX idea more flexible.

 

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In your video, the second frequency on the RX12 is highlighted in red which means it is outside the 35MHz filter. This would explain the poor performance of that channel. Given this, I'd suggest you perform your RF tests again and verify the filter passbands are the same on the RX12 and your Micplexer.

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Patrick may have nailed it.  What was the CENTER FILTER FREQUENCY set to?  If it was tuned for the bandwidth of Block 20, the results you obtained would make sense based on the receiver frequencies.

SIDE NOTE:  Another way in which individual QRX200s are more flexible than an RX-12 is if you need to set more than one encryption code.  The RX-12 uses one encryption code for all the plug-in units.  I opted for multiple QRX200 receivers over a single RX-12 (I had both on site) for a job a couple of months ago for that reason.

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A few thoughts here:

The dual mode performance of the RX12 is exactly the same as the QRX200. It has to be because it uses the same hardware and software.  Receiver diversity or single mode is always the best way to go if the number of transmitters being received makes this possible. 

SMA connectors were chosen for the RX12 to be compatible with all other Zaxcom receivers. BNC would of course be faster to change but would be odd for any Zaxcom customer who would now need 2 styles of antenna.

The Fan on the bottom of the receiver is designed for intermittent use on sound carts and is not generally needed for sound bag operation. If it is used it would only need to move a very small amount of air. Its position is no problem in the sound bag.

 

Glenn

 

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19 hours ago, RadoStefanov said:

537.3 and 571.9 inside the filter

These two frequencies are barely within the 35mhz window. I'd be curious if the results would differ if the frequiences were a bit closer to each other - it could be an issue with the filter in that specific unit that it is cutting off one end of the 35mhz window.

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Given that they are almost 35mHz apart, the center frequency needs to be exactly between them at 557.6 to each be within the 17.5 mHz range from that center.  And due to the roll-off curve of the filter, this is not ideal -- 25 mHz (or less) apart, with the filter's center frequency exactly between the two receiver frequencies, is a better setup.

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5 hours ago, Jack Norflus said:

These two frequencies are barely within the 35mhz window. I'd be curious if the results would differ of the frequiences were a bit closer to each other - it could be an issue with the filter in that specific unit that it is cutting off one end of the 35mhz window.

 

5 hours ago, John Blankenship said:

Given that they are almost 35mHz apart, the center frequency needs to be exactly between them at 557.6 to each be within the 17.5 mHz range from that center.  And due to the roll-off curve of the filter, this is not ideal -- 25 mHz (or less) apart, with the filter's center frequency exactly between the two receiver frequencies, is a better setup.

John and Jack. I am very familiar with the 35mhz Zaxcom filter. Going a little over the set 35mHz is not a big deal. So before we get any further defending I might have found the reason for the negative Dual Mode result. The SMA to BNC antenna cable I used on the RX12 was giving me the poor result on my OneUnit this afternoon on set. After a quick trouble shooting I noticed the SMA center pin was not sticking out enough. I will repeat the test tomorrow with another cable just to be sure.

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No need for "defending," Rado.  Neither Jack nor I were attacking you or challenging your knowledge.  We were simply looking at possible explanations for the RF level deficiency.  

The detail included makes no assumptions as to knowledge, or lack of it.  Rather, this is a discussion group and we're aware that there are many people following these discussions and learning from them.  For instance, there are no doubt those who aren't aware that the extremes of a bandwidth are typically defined by the 3dB roll-off points, which essentially yeilds the same signal strength as transmitting with half the power at a 0dB point on the band's curve.

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So it was the cable. retesting showed better performance in dual mode but still antenna B on the first module had less reception then the same freqs on the other modules. The combination of the antenna and possibly not optimal module one performance are responsible for the horrible test result. I am redacting the review

 

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