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Lectro 200c into SRb issues


Jesse Flaitz

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I've been using a 400a and SMQV with my SRb, but I don't use it that much so I decided to try running 2x 200c into the SRb.  I'm having some issues with the noise floor using the 200cs.  It sounds very choppy to me over using the 400a and SMQV.  I called Lectro and they said it was the compander working in a very quiet environment, and it happens will all 200 series.  The strange thing, is this doesn't happen with my 211/200c system.

 

The 400a/SMQV are operating on the same freq. as the 200cs.  It's only an issue with very low sounds, but I can still hear it.  I've got 3 recordings here, one with the 400a going into the SRb, one with a 200c going into the SRb, and one with a 200c going into a 211.  The 400a and 200/211 combo sound consistent while the 200c into SRb sounds very choppy to me.

 

I gained up the recordings quite a lot with 42dB gain on both 200c recordings, and 36dB of gain on the 400a.

 

http://soundcloud.com/jesse-flaitz/sets/srb-test

 

Any thoughts?  I'll probably stick with the 400a and SMQV combo.

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(smile) Thanks for the very nice introduction, Larry.  I'll have to get our administrator to help me since soundcloud.com is blocked from internal company access.  Once I get to listen, there's a good chance I'll have an opinion.  Oh, it could be wrong, but I've been listening to these modes a lot lately, and pretty intently at that!

 

I'll post again once I get my ears on the audio.

 

Fanatically Yours,

-DT

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I've played the files now, and I definitely see what you mean about the "choppy" nature of the noise floor.  It sounds like the SRb uncompanding is mistracking slightly in response to energy in the bass frequencies (such as HVAC noise or traffic noise).  An interesting test might be to try the 200c into the SRb again without a microphone plugged in to the transmitter.  My guess is that the noise floor would then be smoother, since there would be no mic to pick up those bass frequencies.

 

Your request is very timely as I am just now revisiting some of our analog compatibility modes and trying to work out the subtle reasons why some receiver models decode 200 Series with a little more accuracy than others, despite the fact that the algorithm is supposedly the same.  The differences can be due to the mathematical precision used in various DSPs, differences in the hardware itself, and just plain programming bugs.

 

I'm not sure what the solution is yet, but with the bosses' approval, I'll try some 200 Series transmitters with various current receivers and see if some yield cleaner noise floors than others.  If so, I'll try to figure out what's different; if not, I'll see about perhaps improving the algorithm.

 

Thanks very much for posting.  I have a strong preference for getting this stuff right!

 

Fanatically Yours,

-DT

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I have an SRb on short back order with my audio dealer. I intend to use it with two 200c tx until I can afford the upgrade to new tx.

 

I wonder if I should put a hold on that order until this gets sorted out.

 

If the solution is a change in the SRb programing, could that be done remotely or would it need a trip back to New Mexico?

 

Bob

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Update David, I did test it with no mic plugged in and it still has the same issue.  I'm now guessing it's not an issue with how the electronics respond to what the mic hears.  I think I found a 200D in blk 24 to further troubleshoot against, so hopefully I can post tomorrow with the result.

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Unfortunately I wasn't able to find the blk 24 200 series RX to test against, but I did use a 411a in 200 mode and not surprisingly got the same result as with the SRb.  They are being looked at now to see if there are any problems with the 200cs themselves.

 

Has anyone else used them with an SRa/SRb that can comment?

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  • 3 weeks later...

So the word from Lectro is that it stems from the compatibility problems of the SRb with 200 series TX.  They are looking into ways to stop this issue, but for now I'd recommend not using 200 series TX with SRbs (SRas supposedly do not have these problems, but I'd still test it before buying).

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  • 1 month later...

Maybe slightly off topic, but in the last project i rented a Venue with LM and LMa transmitters and they gave me a SRA receiver too, for bag situations.

I found this was not usable with my txx (sanken cos 11s mounted) because audio sounded overloaded even at low levels.

Maybe they didn't know some compatibility issue, so asking here: anyone knows where is the problem?

Need a different wiring or simply that txs are not compatible with the sra?

thanks, v.

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this sounds like a frequently discussed  issue of correctly wiring COS-11's for Lectro...

the correct wiring is found on Lectro's website.

 

Thanks senator, i was not sure where in the chain was the problem (to search for that). Now i can make my own research.

thanks again, v.

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So the word from Lectro is that it stems from the compatibility problems of the SRb with 200 series TX. They are looking into ways to stop this issue, but for now I'd recommend not using 200 series TX with SRbs (SRas supposedly do not have these problems, but I'd still test it before buying).

Tried to help someone with this issue on FaceBook today and he shut me down. Doesn't pay to be rude to those trying to help you. Glad to see I was correct, and still I hope he has good luck with his outcome.

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there is another current thread discussing wiring a Sanken COS-11 to a TA5F (for Lectrosonics)

 

The thing that seemed strange to me was that the same transmitters with the same sanken cos11s worked great (as request) if the receivers were the venue ones, so the reason i thought it was a tx-rx setup or compatibility problem over a sanken wiring problem.

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  • 2 years later...

Just wanted to bump this thread and see if anyone is currently using UM200C's with their SRb's without issue? Might be pulling the trigger on some gear this week but was hoping to use older Tx's for now until I'm ready to upgrade those as well. 

Edited by BradTheSoundGuy
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Hey Brad,

The key will be making sure you have full modulation on the UM200c.  Keep in mind, however, that the 200 series was still companded analog and will have compander artifacts which are much more noticeable if the modulation is set too low.  Look for two green LED's on the transmitter when setting up and it should sound fine.

 

Gordon

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