Zaxcom QRX100 - Questions For Glenn

[Splendid]

Tim, I had this same issue with an older zaxcom wireless link on a dsr 450. Listening on the mix was distorted but listening to the individual channels was fine. I never worked out why it happened though. The final recording was absolutely fine, just not the mix monitoring…hmmm

[Derek H]

Tim,  if you are talking about the return feed from the camera being distorted despite levels looking fine (meter in ifb option menu) then I experienced the same thing.  A weird combo of seeming like there isn't enough level going into the qrx and then clipping almost immediately when you increase the input gain...  Since you also experienced it I'm now thinking that it's a zaxcom firmware or hardware issue.  Not sure, haven't really investigated enough.

I gave up on it also, but found that if I forget about the 3.5mm external ifb input on the qrx and simply used a mix of the received audio from the qrx: then things were sounding good.  Doesn't confirm audio return from camera but does confirm it at least made it to the receiver.  Again, a compromised solution for a feature that was already just a bonus so... Shrug.  I would like to be able to use the external ifb 3.5 mm in the future though so hopefully they sort it out

[glenn]

With the IFB audio input on the QRX100 verify that you are not set to L-R audio input unless the input is balanced. If inputs are unbalanced use L+R or left or right only.

Early versions of IFB software would clip 6dB before the actual input clip point when used in L-R balanced mode.

The IFB audio range from the QRX100 to the internal receiver in the TRX900 will be about 50 ft. Time code transmission range will be 100-200 Ft. With the ERX1 receiver the IFB range will be as much as 200FT.

For better TRX900 receiver operation make sure the "Drop out compinsator" in the TRX900 extended menu is on. This will eliminate short duration dropouts.

Glenn

[TimPitot]

return feed from the camera being distorted despite levels looking fine (meter in ifb option menu) then I experienced the same thing.  A weird combo of seeming like there isn't enough level going into the qrx and then clipping almost immediately when you increase the input gain...

Tim, I had this same issue with an older zaxcom wireless link on a dsr 450. Listening on the mix was distorted but listening to the individual channels was fine. I never worked out why it happened though. The final recording was absolutely fine, just not the mix monitoring…hmmm

Yup that sounds exactly like what I am experiencing.

I did another test today, QRX into 788T, sounds fine on L,R monitor but if I pan both channels to either Left or Right, the problem persists, if I then reverse the phase of one of the channels on the 788, it goes away. So, phase issue.

Hopefully I will get a replacement cable tomorrow to see if its a wiring fault or if its coming from the QRX.

IFB is set to OFF by the way.

[TimPitot]

Forgot to say, Derek, I am hearing this directly out of the camera/788 headphone jack.

[ben lowry]

Tim,

For phase canceling issues when your channels are summed after the receiver, double check your transmitter input cables too. The pinout for the TA5 on the STA-100/150 and the IFB100 has pins 4 & 5 reversed from how I usually see 5-pin stereo connectors laid out. That is, these inputs expect 1=grd, 2=L+, 3=L-, 4=R-, 5=R+

Ben Lowry

[glenn]

We have just released TRX900 software version 7.23. This has a phase reverse feature for one of the channels of the stereo transmitter. This should take care of the problem.

This version also has changes to provide better SD card compatability.

Glenn

[Derek H]

Glenn, will 7.23 make any changes in how the auto load feature works?

[TimPitot]

Replacement cable did not solve the issue.

[Jack Norflus]

Replacement cable did not solve the issue.

Tim,

What exactly is the problem you are having?

Is the distorted audio the audio comming out of the QRX into the camera? Or is the distorted audio the return audio that you are hearing comming back to the TRX via the mini TRS audio in on the QRX? Or is it something else?

If it is the IFB return - what output are you using to feed the audio in of the QRX?

Jack

[Splendid]

When I had this issue it was when listening on the CAMERA HEADPHONE JACK, headphone plugged directly in. nothing to do with the ifb as my audio send to the camera was with the rx900s. Listening with the camera monitor switch set to mix it was totally distorted, at all levels, regardless of altering input level at either the camera end, bag end, or on the zaxcom link. Flicking to either left or right channel it was perfectly fine. The camera was a dsr450. The final recording was fine though so it didnt matter, but not much use if the camera op wanted to listen to a mix...

[Jack Norflus]

When I had this issue it was when listening on the CAMERA HEADPHONE JACK, headphone plugged directly in. nothing to do with the ifb as my audio send to the camera was with the rx900s. Listening with the camera monitor switch set to mix it was totally distorted, at all levels, regardless of altering input level at either the camera end, bag end, or on the zaxcom link. Flicking to either left or right channel it was perfectly fine. The camera was a dsr450. The final recording was fine though so it didnt matter, but not much use if the camera op wanted to listen to a mix...

So when you did playback on both Left and Right tracks together was the audio fine? Was the distortion only in EE monitoring? Did the audio playback fine on another machine?

[glenn]

Sounds like the audio feeding the camera was out of phase. The TRX version 7.23 has a phase invert function that can fix this without having to rewire any cables.

Glenn

[TimPitot]

Splendid - exactly. Ifb not part of the equation

[johnpaul215]

Is there any reason that you could not send from a TRX900/STA150 to a 2 channel QRX100 and a RX900S at the same time?

I already own a stereo hop set, but only have 1 RX. If I got the QRX100, could I use that on the A camera (and maybe use the QIFB for confidence/IFB), and put my RX900S on the B-cam if I had a need?

[Jack Norflus]

Is there any reason that you could not send from a TRX900/STA150 to a 2 channel QRX100 and a RX900S at the same time?

I already own a stereo hop set, but only have 1 RX. If I got the QRX100, could I use that on the A camera (and maybe use the QIFB for confidence/IFB), and put my RX900S on the B-cam if I had a need?

As long as all your Zaxcom gear is in the same block all will be good.

[Derek H]

John paul,

Absolutely.  Obviously they need to be on the same block but yes all the trx and receivers are compatible.  I've actually done exactly that on a shoot already. 

Used my old black case eng receiver on b cam and the qrx on the A cam.  Works flawlessly.  Audio quality seems identical to my ear though the qrx seems to have a hotter line output.  Have yet to find a camera that the qrx cannot feed line level... This was a problem with the previous zax receivers.

[johnpaul215]

Jack and Derek,

That's great to hear. I've had a few mechanical issues doing wireless hop on this current job (bad power cables etc), and working with a camera op that really doesn't like wearing headphones. That's just one more reason the QRX100 would be great.

The LEDs would immediately indicate a problem, and the IFB would drop out for the producer (and I could monitor a return). I'm a bit taller than my camera op, so I can often see the RX900 top LED, but the QRX ones would be even easier to see.

[Jack Norflus]

The LEDs would immediately indicate a problem, and the IFB would drop out for the producer (and I could monitor a return). I'm a bit taller than my camera op, so I can often see the RX900 top LED, but the QRX ones would be even easier to see.

When I first got my QRX I thought that the LED's would be a cute but frivolous feature - but it turns out that the LEDs has become one of my favorite features on the unit. I have mine set that the LED's go blue when RF is getting to the QRX but there is no audio and then the LED's go green when there is audio present. The LED's are also plenty bright so they can be seen outside on a sunny day.

[Andy P]

I'm just about to buy a QRX but I've got a question about the internal IFB board. I want to use the QRX in a bag as a dual receiver but am looking to get another QRX soon with two more TRX900LT's, so a total of 4. If I get the IFB board fit in my first QRX, will it be able to control the third and forth TRX's freq and gain settings? Obviously the audio won't be being received and output by the first QRX.

If this is not the case would I be better off getting an IFB100 so I can control all the TRX's?

[TimPitot]

We have just released TRX900 software version 7.23. This has a phase reverse feature for one of the channels of the stereo transmitter. This should take care of the problem.

This version also has changes to provide better SD card compatability.

Glenn

Glann, the newest firmware I can see on the website is 7.02.

Has 7.23 been released yet?

[Matthias Richter]

I'm just about to buy a QRX but I've got a question about the internal IFB board. I want to use the QRX in a bag as a dual receiver but am looking to get another QRX soon with two more TRX900LT's, so a total of 4. If I get the IFB board fit in my first QRX, will it be able to control the third and forth TRX's freq and gain settings? Obviously the audio won't be being received and output by the first QRX.

If this is not the case would I be better off getting an IFB100 so I can control all the TRX's?

as answered by Glenn in this thread already you can control various TRX with one QRX when hooked up to a Deva / Fusion. A single QRX can control the 2 TRX it is tuned to.

http://jwsound.net/SMF/index.php?topic=6173.msg67160#msg67160

Matthias

[Twade]

I'm just about to buy a QRX but I've got a question about the internal IFB board. I want to use the QRX in a bag as a dual receiver but am looking to get another QRX soon with two more TRX900LT's, so a total of 4. If I get the IFB board fit in my first QRX, will it be able to control the third and forth TRX's freq and gain settings? Obviously the audio won't be being received and output by the first QRX.

If this is not the case would I be better off getting an IFB100 so I can control all the TRX's?

Hi Andy,

You can do it with the QIFB. The QIFB is the same as the IFB100. The difference is the menu isn't immediately apparent.  You simply have to dig deeper in the menu of the QRX to get the the IFB options.

[Boomboom]

I'm not sure the QRX ifb option is exactly = to IFB100. A few slight differences from what I read here.

For one, I read recently that you don't have the REC-STOP function when  the QRX's embarked on cam. IFB100=yes.

Also: I'm reading right now that "you can control various TRX with one QRX when hooked up to a Deva / Fusion". That part in italics seems to be different concerning the QRX and the IFB100. The latter will have all the remote functions if you use an SD 552 in your bag for example... (please confirm this assessment?)

On the other hand, with the QRX you can generate time code (''master clock''). An very nice option that might be added to the IFB100 soon...

Bottom line: all these minor differences seems subject to change ... I can't talk for Zaxcom but it seems in a near future, both QRX and IFB will, effectively, have exactly the same functions; it seems Zaxcom are working on this already. These guys are fast at programming/coding mods and features !    :-)

[Andy P]

For what I need it for, changing various transmitter's gain and frequencies,I heard from Roger the UK Zaxcom distributor that you can do so with the QIFB. All the TRX's show up with specific ID's and you can alter settings then. Just as Twade has indicated.

I'm working without a Deva or Fusion but maybe soon with a Nomad so who knows what QIFB ramifications that will bring to the fore,if any? Let's not go there for now..