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F Enholmer

SMQV SRb Hop Modes

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400 mode is native for your equipment. 

Tx and rx should be 400 mode for optimum audio. 

If you're using SM transmitters on talent and you use the remote control tweedle tones on talent mics, you should disable the remote control on your hop transmitters otherwise every time you make an adjustment on your talent tx, it will change your hops too, unless the faders are down on your mixer. 

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I also set "smartNR" to OFF since this is intended to reduce the self noise of lav mics. Not necessary when feeding line level from a mixer but that's my personal preference.

 

Most people just leave it in normal I suppose.

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It is probably best not to have two NR setups in series, one at the transmitter and one in the hop. Two doses of subtle may not be subtle anymore. Also, the SNR works on room noise, particularly air handlers, as in the whisper of air vents.

Best, Larry F.

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Good tips gentlemen, thanks.

This is my hop setup:

Mixer outputs at -10 (688 X1 & X2)

SMQV's level at 29 so that both -10 and -20 light are illuminated when sending tone at 0db

SRb level set to 0

With this setup I still need to add +10db on the camera to reach unity which isn't ideal obviously.

When I run tone only from the SRb I reach unity on the camera without needing to add gain.

Any ideas what I'm doing wrong?

 

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SRb level can be set to +5 I guess.

I'm not a regular Lectro user, but someone here (Larry?) once said that +5 is the "normal" mode and all other values are only attenuations. So you don't need to add so much gain on camera.

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I send tone so both lights on the SM light up and then back it off a hair until the -10dB light goes off.  Gain setting of 12 in my case using line level input cable and -10 mixer line output. I could use full 0 line level out of the mixer but this requires a transmitter gain setting of 2 and it seems a bit scary but maybe it's OK, I don't know.

 

I generally use mic level input on camera. I'll set the trim on the camera to a bit under the 50% detent and then set the SRb output to wherever lines up the tone to -20dBFS.

 

I think everyone has their own preference and method but this works well for me. I find if I try to use line level input on the camera I need a lot of gain at the camera trim to get it to -20 and I hear more self noise in the headphone than if using mic level and keeping the gain low. 

 

From what I've heard many camera's line inputs are simply applying attenuation and feeding at mic level anyway in which case I think it's better to just start with a hot mic level rather than a weak line level. Assuming you have good cables and aren't picking up some cable borne noise.

 

I formerly used Zaxcom for hops which had a nice hot line level so it was a different story (qrx100). Lectro at +5 doesn't always have enough for noisy camera inputs. 

 

Now that everything is recorded at 24bit in the bag I find I don't care as much about these little camera hop details. More and more it's just a reference anyway which I prefer. 

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From what I understand, both of the above are lining up -20dbFS from the mixer to -10 on the transmitter. That would be pushing very hard into the Tx limiters.

Seems a bit off to me.

BTW, I very rarely use these as hops.

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3 hours ago, F Enholmer said:

Good tips gentlemen, thanks.

This is my hop setup:

Mixer outputs at -10 (688 X1 & X2)

SMQV's level at 29 so that both -10 and -20 light are illuminated when sending tone at 0db

SRb level set to 0

With this setup I still need to add +10db on the camera to reach unity which isn't ideal obviously.

When I run tone only from the SRb I reach unity on the camera without needing to add gain.

Any ideas what I'm doing wrong?

 

As mentioned by Mungo, use +5 on SR. You can't overload  any of our receivers by running them wide open and you will reduce ground loops and other injected noise. Use the full output  of the SR before using other make up gain.

Best, Larry F.

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On 10/12/2016 at 11:19 PM, LarryF said:

Also, the SNR works on room noise, particularly air handlers, as in the whisper of air vents.

 

Really, I did not know that, I don't believe it is discussed in the manual. Tell us more o great retired Lectro maven.

 

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I have my srb set to +5 output to camera line level in. I come out of my mixer at 0db and have the smqvs set to 12 with the -10 light just barely lighting up. It gives me a nice strong signal and sounds good. I'm also feeding the transmitters with a line level cable. 

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On 10/14/2016 at 9:27 AM, al mcguire said:

Really, I did not know that, I don't believe it is discussed in the manual. Tell us more o great retired Lectro maven.

 

Smart Noise Reduction, SNR, is a sliding low pass filter that stays about 1 octave above any real signal in the upper midrange and high frequencies. The reason for a sliding filter is that it can get out of the way very quickly without causing artifacts, i.e., it can go from a 1k low pass to a 10k low pass in a millisecond or less without causing a click and without destroying the leading edge of a sibilant. The speed of "release" is set by three pieces of data: the RF level of the received signal, the amount of high frequency information in the audio and the upper frequency of that audio. In the all analog 200 series all this was done with active filters, multipliers and gain cells. The math was simple: Filter Frequency = (audio signal level) times (audio frequency) times (RF Level). The filter could go as low as 800 Hz and as high as 50 kHz. In the 400 series, it is done in the DSP. The 200 series required precise adjustments and measurements to make sure every unit was tracking the desired filter curves. Now, it's "just" a program, exactly repeatable.

As to lavaliere self noise and air handlers. These are random noise like signals (pink noise like generally) and the receiver SNR treats these signals like any other low level upper midrange (and higher) noise. It applies a lowpass filter until there is a sufficiently strong signal to drive the filter frequency upwards. That is to say, it will reduce these noise signals just as if they were in the RF link or electronics. Generally SNR improves the sound and does it on a single mic basis. It is much easier to reduce the noise on a mic by mic basis than after multiple mics are mixed together.

If you don't like the idea of filters dancing all around your sound no matter how subtle, SNR can be reduced or switched off. We, in fact, attempted to ship the first 400 series without SNR and ran into a firestorm of "it doesn't sound as good as the 200 series" and "the lavaliers sound hissy". Being no fools, we quickly put it back into the system. If you do AB comparisons, keep in mind that low level noise (hiss) will make a signal sound brighter since it preloads the ear's cilla. Ray Dolby proved this years ago, when he got complaints about Dolby noise reduction dulling recordings. He simply took a clean track of audio and introduced low level hiss. Nearly every listener found the low level hiss made the track "brighter". 

I will say, SNR works best on voice signals since vocal sounds take many milliseconds to develop. If you were recording low level transients (the snap, crackle and pop of Rice Krispies for instance) you might then consider switching SNR off.

Best Regards,
Larry F

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As an update to my previous post I just ran into a scenario where an on-camera Teradek was causing intermittent noise to be picked up in the camera audio. Setting the Lectro receiver to full tilt +5 and using line level input on the camera solved the issue. 

 

 

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On 10/18/2016 at 5:07 PM, LarryF said:

Smart Noise Reduction, SNR, is a sliding low pass filter that stays about 1 octave above any real signal in the upper midrange and high frequencies. ... snip ...As to lavaliere self noise and air handlers. These are random noise like signals (pink noise like generally) and the receiver SNR treats these signals like any other low level upper midrange (and higher) noise. It applies a lowpass filter until there is a sufficiently strong signal to drive the filter frequency upwards. That is to say, it will reduce these noise signals just as if they were in the RF link or electronics. Generally SNR improves the sound and does it on a single mic basis.

Larry,  with an LR receiver when would you use High Smart Noise Reduction rather than Normal SNR?

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