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Author Topic: Shure UHF-R noise  (Read 6292 times)

Ike Zimbel

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Re: Shure UHF-R noise
« Reply #10 on: February 24, 2017, 01:32:05 pm »

Hi Ike,

Wow, thanks for your reply and for taking some measurements. Unfortunately I do not have the tools to do a noise measurement myself.
However, tonight I will be using the setup again and will spend some extra time setting up levels, I will report back on that later.
Probably tomorrow I will have the chance to compare a couple of different UR4D+ receivers, to see if any of those units may be faulty.

Anyway, your measurements show that noise should really not be a problem with these units. Considering the amount of noise that I am experiencing, I really think some of my receivers may be faulty. I'll try to find out what's going on this weekend.
No Problem, I was curious myself. And yes, with these numbers you shouldn't be having noise floor issues with any of these devices.
To get through your show I recommend trying the TRS outputs.
I haven't heard of any issues with UHF-R, but some of the older Shure UHF series units did have an issue with noisy outputs that was, IIRC, due to some capacitors in the output stage going bad. Let us know what you find out.
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hugovanmeijeren

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Re: Shure UHF-R noise
« Reply #11 on: February 27, 2017, 09:19:41 am »

No Problem, I was curious myself. And yes, with these numbers you shouldn't be having noise floor issues with any of these devices.
To get through your show I recommend trying the TRS outputs.

So I promised to get back on this. I did end up using the TRS outputs for the show on Friday, I also undid the -10dB gain on the beltpacks (0dB sensitivity, 0dB gain) and I padded the input on the SD11 and compensated with a 10dB gain (equal to '0dB' on the mixer) to come to a comfortable level for the show. This greatly reduced the noise floor issues that I was having. However, comparing again to the EW100 G3 I was also using on that show, the UHF-R receivers were still a bit more noisy.

On Saturday I had time to do some extra testing. What I did was the following: I took 2 UR4D+ receivers (1 I had used on the show on Friday and 1 from another batch) and connected the 4 outputs to an SD11. On both receivers Channel 1 was connected through the XLR out and Channel 2 was connected through the TRS outputs. I made sure that both units were set-up completely identical. (line level output, 0dB gain, same frequency, no transmitter)
Hooked up to the SD11, no pad engaged, no extra gain applied (+10dB).
First I did a listen test, using headphones, comparing noise floor levels of both units. The noise floor on both XLR outputs was identical to my ear and fairly substantial. The noise floor on the TRS outputs of both units was also identical, but much lower than from the XLR outputs.
Next I took a UR2/beta 58A transmitter and fed in pink noise through a loudspeaker in front of the microphone. Audio output from the TRS outputs was much lower than from the XLR outputs (due to the different balancing method for both outputs of the receiver apparently). I gained up the Channel 2 (TRS) inputs on the SD11 and found that with +6.5dB I got identical levels to the XLR outputs of the UR4D+ receivers.
I did a listen test again (UR2 transmitter switched off) and could now hear identical noise floor levels on all 4 inputs to the SD11. So in this regard, the TRS outputs do not have a lower noise floor than the XLR outputs. Their general level (including noise) is much lower. Interestingly, your noise measurements show the exact same 6.5dB difference (-89.1dB and -95.60dB).

Finally, I hooked up a Sennheiser EW100 G3 receiver (no transmitter) and turned up its output gain to +18dB (max level). With no extra gain applied on the SD11, I could only barely hear some noise on the Sennheiser receiver. It was almost dead quiet compared to the Shure receivers...

So, the lesson I have learned is the following I think: the noise floor of the Shure UHF-R is higher than of the Sennheiser EW100 G3. The gain structure on the Shure system needs some special attention, but when correctly applied, noise levels are quite acceptable.
I think I was too used to the Sennheiser systems not needing any particular attention to avoid noise floor issues, that I made a mistake when using the Shure system, resulting in an improper gain structure.
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Hugo van Meijeren

Scott Helmke

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Re: Shure UHF-R noise
« Reply #12 on: February 27, 2017, 10:14:02 am »

One thing to be aware of with analog wireless is that a high RF noise floor can cause a high audio noise floor. Is it possible the UHF-R systems are in a more congested frequency band than the Sennheiser systems?
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hugovanmeijeren

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Re: Shure UHF-R noise
« Reply #13 on: February 27, 2017, 10:39:33 am »

One thing to be aware of with analog wireless is that a high RF noise floor can cause a high audio noise floor. Is it possible the UHF-R systems are in a more congested frequency band than the Sennheiser systems?
No, they are basically working in the same frequency band: Shure K4E (606-666 MHz) and Sennheiser B-range (626-668 MHz).
There are no incoming RF signals according to measurements with a spectrum analyser.
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Hugo van Meijeren

Kevin Maxwell

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Re: Shure UHF-R noise
« Reply #14 on: February 27, 2017, 11:02:56 am »

So I promised to get back on this. I did end up using the TRS outputs for the show on Friday, I also undid the -10dB gain on the beltpacks (0dB sensitivity, 0dB gain) and I padded the input on the SD11 and compensated with a 10dB gain (equal to '0dB' on the mixer) to come to a comfortable level for the show. This greatly reduced the noise floor issues that I was having. However, comparing again to the EW100 G3 I was also using on that show, the UHF-R receivers were still a bit more noisy.

On Saturday I had time to do some extra testing. What I did was the following: I took 2 UR4D+ receivers (1 I had used on the show on Friday and 1 from another batch) and connected the 4 outputs to an SD11. On both receivers Channel 1 was connected through the XLR out and Channel 2 was connected through the TRS outputs. I made sure that both units were set-up completely identical. (line level output, 0dB gain, same frequency, no transmitter)
Hooked up to the SD11, no pad engaged, no extra gain applied (+10dB).
First I did a listen test, using headphones, comparing noise floor levels of both units. The noise floor on both XLR outputs was identical to my ear and fairly substantial. The noise floor on the TRS outputs of both units was also identical, but much lower than from the XLR outputs.
Next I took a UR2/beta 58A transmitter and fed in pink noise through a loudspeaker in front of the microphone. Audio output from the TRS outputs was much lower than from the XLR outputs (due to the different balancing method for both outputs of the receiver apparently). I gained up the Channel 2 (TRS) inputs on the SD11 and found that with +6.5dB I got identical levels to the XLR outputs of the UR4D+ receivers.
I did a listen test again (UR2 transmitter switched off) and could now hear identical noise floor levels on all 4 inputs to the SD11. So in this regard, the TRS outputs do not have a lower noise floor than the XLR outputs. Their general level (including noise) is much lower. Interestingly, your noise measurements show the exact same 6.5dB difference (-89.1dB and -95.60dB).

Finally, I hooked up a Sennheiser EW100 G3 receiver (no transmitter) and turned up its output gain to +18dB (max level). With no extra gain applied on the SD11, I could only barely hear some noise on the Sennheiser receiver. It was almost dead quiet compared to the Shure receivers...

So, the lesson I have learned is the following I think: the noise floor of the Shure UHF-R is higher than of the Sennheiser EW100 G3. The gain structure on the Shure system needs some special attention, but when correctly applied, noise levels are quite acceptable.
I think I was too used to the Sennheiser systems not needing any particular attention to avoid noise floor issues, that I made a mistake when using the Shure system, resulting in an improper gain structure.

Your noise floor results are completely opposite to my experience. The Sennheiser EW series has always been a lot noisier the the Shure UHF-R. I don't know why you are getting different results. I always run mic level out of the transmitters, that is the only difference that I can see between what you do and what I do. I have never used the 1/4" outs. Do you use Wireless Work Bench to monitor your wireless during the show? If yes how do the levels look on the Shure wireless?
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hugovanmeijeren

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Re: Shure UHF-R noise
« Reply #15 on: February 27, 2017, 11:15:43 am »

Your noise floor results are completely opposite to my experience. The Sennheiser EW series has always been a lot noisier the the Shure UHF-R. I don't know why you are getting different results. I always run mic level out of the transmitters, that is the only difference that I can see between what you do and what I do. I have never used the 1/4" outs.

Ah, I forgot to mention it. During testing on Saturday, I also switched the UR4D+ to mic level. After compensating the input gain on the SD11 to match audio levels as with the line level output, I've found the mic level output of the UR4D to have slightly more noise as compared to line level.

Do you use Wireless Work Bench to monitor your wireless during the show? If yes how do the levels look on the Shure wireless?
Do you mean AF levels? For this show, I only used WWB for initial set-up, not for monitoring during the show. I try to set gains on the transmitters in such a way that I average around the first yellow LED on the receiver.
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Hugo van Meijeren

Lee Buckalew

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Re: Shure UHF-R noise
« Reply #16 on: February 27, 2017, 03:24:28 pm »

Your noise floor results are completely opposite to my experience. The Sennheiser EW series has always been a lot noisier the the Shure UHF-R. I don't know why you are getting different results. I always run mic level out of the transmitters, that is the only difference that I can see between what you do and what I do. I have never used the 1/4" outs. Do you use Wireless Work Bench to monitor your wireless during the show? If yes how do the levels look on the Shure wireless?

Kevin,
You mentioned previously that your experience was with EW G2.  Those were a very different system in terms of audio performance than G3. 
Just a thought as to one possible reason for the discrepancy.

Lee
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Kevin Maxwell

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Re: Shure UHF-R noise
« Reply #17 on: February 27, 2017, 11:20:47 pm »

Kevin,
You mentioned previously that your experience was with EW G2.  Those were a very different system in terms of audio performance than G3. 
Just a thought as to one possible reason for the discrepancy.

Lee

I just realized that I had written a response to where you mentioned that and I forgot to post it. I was only referring to one situation when I mentioned the G2s. I have also used a mix of G2 and G3 and I donít think either one of them is quieter then the Shure UHF-R. I am just sharing my experience. I have also used a lot of different wireless over the years. More years and more wireless then I care to bring up at the moment.
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Lee Buckalew

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Re: Shure UHF-R noise
« Reply #18 on: February 28, 2017, 06:57:18 am »

I just realized that I had written a response to where you mentioned that and I forgot to post it. I was only referring to one situation when I mentioned the G2s. I have also used a mix of G2 and G3 and I donít think either one of them is quieter then the Shure UHF-R. I am just sharing my experience. I have also used a lot of different wireless over the years. More years and more wireless then I care to bring up at the moment.

Interesting.  My experience has been just the opposite when comparing with identical Mic capsules. 

Lee
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Christopher Irwin

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Re: Shure UHF-R noise
« Reply #19 on: February 28, 2017, 03:09:20 pm »

I work with a few UHF-R mics weekly on a Digico console and have had a similar experience with the UHF-R being much noisier than other wireless systems (both G3 and the older/chepaer ULXP).  I experience a lot of HF hiss - I will sometimes grab a high shelf eq and turn it down to help reduce this because for me it is worth the compromise :(.

I personally wonder if 1. my (2) units have an issue than no one else has 2. other engineers have lost some of their HF hearing and so don't notice OR 3. other engineers are in a noisier environment and so don't notice as much? 

Anyway, I also spend a fair amount of time fiddling with sensitivity and gain which does help some, but has to be changed for different situations (singing vs. speaking being the biggest difference)- and yes the noise is in the system whether or not the packs/handhelds are turned on, this fiddling just seems to keep it from getting really bad.

Maybe someone here knows better than me, but I have heard that a reason for this is because Shure was trying to eliminate (?) the audio compander? Or some such thing.

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Re: Shure UHF-R noise
¬ę Reply #19 on: February 28, 2017, 03:09:20 pm ¬Ľ


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