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Parapluie

Lectrosonics SRb vs UCR411a

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Hi!


I'm gonna upgrade my audio kit and get a good quality wireless system. I think I will go for Lectrosonics after reading much positive about them. I want the oportunity to have 6 reliable radio mics in my audio bag. 


I think I will go for the SMDB/01 transmitters (I'm from Europe)
But I'm not sure which receivers i should go for. The SRb or UCR411a. 


I like the idea of having just 3 dual SRb receivers, and not 6 UCR411a for the reason of reducing weights and space in my bag - and it's cheaper. But I have read that the UCR411a is more reliable and has better signal strength, range, less drop outs etc than the SRa.


If that's so I'm suddenly leaning against 6 UCR411a again. But how is the new SRb compared with UCR411a in reability, range, drop-outs etc? 


I see many have the SRb in their bags when googling around. So I guess the SRb is a quite good investment after all? 


Any thoughts? 


Thanks

 

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Search through this forum a bit.  Type... "jwsound sr 411" in google - or something like that.  Searching google with jwsound in front of your search will help a lot.

 

What you will find is that 411s will outperform SRbs.  Is it worth the extra cost and weight is up to you.

 

If you can afford it, I'd go with the 411s.  Or you can get 2x 411s and 2x SRbs.

 

Robert

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" 411s will outperform SRbs. "

typically, 411s will outperform SRbs, but not by much, and not in all aspects, or in all circumstances.

see below!

Edited by studiomprd

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I will mix up 411's and SRa's in my bag as needed... if it's a run and gun day, I will keep things as light as possible by using SR's only.

 

If I think I'll need a bit more range, I'll mix in a few of my 411's, if I need up to 6 mics, I will commonly run 2 x 411s, and 2 x SR's for a lot lighter rig. 

 

I have used these units side by side (SRa not SRb) and to be honest, I don't notice a lot of difference in performance between the 2 units. I used them side by side in an extreme race, and the SRa's would be pulling in a signal before the 411s sometimes. 

 

That said, I'm in a reasonably quiet RF zone, so I don't have to worry about interference too much... if that's a worry for you, like for the guys in LA or New York, might want to stick with 411's.

 

I'm currently upgrading my units to SRb's, so I'll report back if I notice any improvement, which I'm told I should!

 

Best, 

 

Rich

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A little bit off topic...what are the differences between smqv and smdb? Only that the power output has a maximum of 50mW in smdb's for Europe? 

 

Yes.

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Somewhat off topic again, when purchasing multiple systems , are you ( anyone ) setting up with multiple frequency block pairs?

 

mike

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Hi,

A little bit off topic...what are the differences between smqv and smdb? Only that the power output has a maximum of 50mW in smdb's for Europe?

Deviation is 50 kHz for Europe and 75 kHz in the Americas.

LEF

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hi larry, out of pure interest:

how does a bigger/smaller deviation affect the quality of the transmitted audio ? better/worse s/n ? i use both systems, us and eu, and they sound identical, as far as my battered ears can hear :-)..

or maybe the difference ist negligible under real world conditions...or just noticeable when improperly modulated ( too low ) ?

best

marco

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Hi!

I'm gonna upgrade my audio kit and get a good quality wireless system. I think I will go for Lectrosonics after reading much positive about them. I want the oportunity to have 6 reliable radio mics in my audio bag. 

I think I will go for the SMDB/01 transmitters (I'm from Europe)

But I'm not sure which receivers i should go for. The SRb or UCR411a. 

 

.......................

 

This is what he said Larry Fisher of Lectrosonics:

 

"In our walk tests with 8 transmitters, SRb is very similar in range to a 411a and definitely better than an SRa. In very tough RF environments, 411a is still superior."

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" how does a bigger/smaller deviation affect the quality of the transmitted audio ?  ? "

If the baseband data signal (the message) to be transmitted is b83a18776558e5421a414c83b93aaecc.png and the sinusoidal carrier is d394074d9e449547ce3f3ac8ec147357.png, where fc is the carrier's base frequency and Ac is the carrier's amplitude, the modulator combines the carrier with the baseband data signal to get the transmitted signal:

470a98ec9e396041f4cbe2c408176021.pngd744f3f0b1df05a7bfa450c7eadec1f2.png1feadfadabb3302817c0514e6b1f0472.png

In this equation, f37f7b822c9beef6dc5ccff04272a00b.png is the instantaneous frequency of the oscillator and 51afc786ea991a586b39ceb9a4d1307a.png is the frequency deviation, which represents the maximum shift away from fc in one direction, assuming xm(t) is limited to the range ±1.

While most of the energy of the signal is contained within fc ± fΔ, it can be shown by Fourier analysis that a wider range of frequencies is required to precisely represent an FM signal. The frequency spectrum of an actual FM signal has components extending infinitely, although their amplitude decreases and higher-order components are often neglected in practical design problems.[4]

Sinusoidal baseband signal

Mathematically, a baseband modulated signal may be approximated by a sinusoidal continuous wave signal with a frequency fm. The integral of such a signal is:

b5ebd92867b2f7e8005b5803021365cb.png

 

Noise Reduction

A major advantage of FM in a communications circuit, compared for example with AM, is the possibility of improved Signal-to-noise ratio (SNR). Compared with an optimum AM scheme, FM typically has poorer SNR below a certain signal level called the noise threshold, but above a higher level – the full improvement or full quieting threshold – the SNR is much improved over AM. The improvement depends on modulation level and deviation. For typical voice communications channels, improvements are typically 5-15 dB. FM broadcasting using wider deviation can achieve even greater improvements. Additional techniques, such as pre-emphasis of higher audio frequencies with corresponding de-emphasis in the receiver, are generally used to improve overall SNR in FM circuits. Since FM signals have constant amplitude, FM receivers normally have limiters that remove AM noise, further improving SNR.

 

 

" better/worse s/n ? "

potentially, yes

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+1 on what RPSharman and Richard Nault said.

Go with your needs and buy both.

Mount your kit according to the gig and bring it all on the set in case you change your mind.

I too mix 411s and an SRb without issues so far. On a "smooth" gig that just needs 2 lavs and a boom, I use my 302, my SRb and am a happy camper . If I was to have issues that could be solved by swapping my SRb for two 411s, they're right into my bag.

But it never happened so far.

:-)

My next buy will be another SRb: I already own three 411s and one SRb.

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Parapluie: what's the RF situation where you work? If it's not too bad, then I would definitely go for the SRb. Maybe you can buy one SRb and test it out before you buy 3 of them, or like suggestion above and mix 411 and SRb receivers. 

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I just thought I'd jump in because this is such an interesting discussion, especially with Professor Senator's mathematical treatment!

 

From a "firmware guy" perspective, the SMQV and SMDB differ in terms of which compatibility modes and RF power levels are enabled. The SMDB is fixed at 50 mW, whereas the SMQV can be set for 50, 100 or 250 mW.  The SMQV offers six compatibility modes: 100 Series, 200 Series, "Mode 3", Digital Hybrid (higher deviation version), IFB, and "Mode 6".  If I remember correctly, the SMDB offers three compatibility modes: "Mode 3" (with enhanced limiter for European compliance), Digital Hybrid (lower deviation version), and IFB (also with enhanced limiter, if I remember correctly).

 

The two versions of Mode 3 are compatible, as are the two versions of IFB mode, but the two versions of Digital Hybrid don't interoperate correctly, due to the different deviation levels.  If you use a low deviation transmitter with a high deviation receiver, the result will be that the transmitter could be in limiting and the receiver is still not showing full scale on the meter.  The other way is worse: if you use a high deviation transmitter with a low deviation receiver, the receiver could clip in situations where the transmitter gives no warning.  I'm also not sure what the disparity in deviation levels might do to the character of the noise floor.

 

Oh, and another subtle point about those different deviation levels: the high deviation Digital Hybrid mode does a better job of hiding the diversity switching "ticks" than the low deviation version.  The SRb of course offers ratio mode, with no diversity ticks, but then you have a more expensive channel.

 

Fanatically,

-DT

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John: my RF situation where I work isn't too bad. So i guess SRb would be a good choice when considering weight and price, if there is very little difference in quality in decent RF areas vs 411. 

 

I suppose that tracking front end feature would be nice in places with more RF-troubles. So maybe a combination of SRbs and 411s is the best route as several of you have mentioned.

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Exactly.  I think its good to have both. 

 

A good example of a circumstance I had yesterday was following a skateboarder on my bicycle through downtown SF.  I had two choices, 411a or SRB.  I chose 411 because of the tracking front end and knowing that block by block, frequencies were probably changing. 

 

Most productions though, SRBs will do just fine! 

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The 411a's shine when it comes to multi channel reality shows. If you intend on using yours with multi crew and multi channel shows, you should consider the 411a more seriously. Especially if it's the type of show where there's alot of dialing up of frequencies. The SR needs certain spacing between the 2 freqs and freq 1 must be lower than freq 2. Remembering all this while under the pump trying to dial someone up can be tricky.

Cheers

Peter Mega

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The 411a's shine when it comes to multi channel reality shows. If you intend on using yours with multi crew and multi channel shows, you should consider the 411a more seriously. Especially if it's the type of show where there's alot of dialing up of frequencies. The SR needs certain spacing between the 2 freqs and freq 1 must be lower than freq 2. Remembering all this while under the pump trying to dial someone up can be tricky.

Cheers

Peter Mega

I believe that now with the SRb, it doesn't matter if freq 1 is lower than freq 2. Something about the physics inside are different in the SRb so this is no longer necessary.

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