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Movies Forum Index » Movie Production (Sound) Forum » Any Lectro block have less interference from SD recorders?
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| Philip Perkins |
 Posted: Fri May 02, 2008 7:01 pm |
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Does any Lectro block have any less (or more) interference from a
Sound Devices recorder mounted close by?
Philip Perkins |
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| Pascal Van Strydonck |
| Posted: Sat May 03, 2008 8:52 am |
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Noah, it's all good. PLus you are right, only distance changes. I
placed my bag like this ( from me ), 744T, 302, Lectros RX, Lectros TX
and the rest of the world.... Of course, if i bring the Lectros RX in
contact with the 744T that's not a really good idea...
Pascal
Pascal Van Strydonck
Concepteur et consultant
Audio
Designer and Consultant
514.755.1900
Email: pascal.vs@mac.com
Website: www.pascalvs.com |
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| Charles Tomaras |
| Posted: Sat May 03, 2008 1:30 pm |
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"-¦-R?b?rto¤" <~*u-¦-e-¦@l¤ess.com> wrote in message
news:s3bp1414sj8k8vn5ugjd5fre772vpbqq0n@4ax.com...
Quote: On Sat, 3 May 2008 09:37:23 -0700, schreef:
"-¦-R?b?rto¤" <~*u-¦-e-¦@l¤ess.com> wrote in message
news:9a4p14lajebairfnhenigqpo4h8fslv9sq@4ax.com...
On Fri, 2 May 2008 23:22:09 -0700, schreef:
new board design to achieve the quieting which is said to be far
quieter than all of the current competitive recorders that were tested.
Interesting. Do they have results that one can see , like different
models/brands and such ?
R ( or is it just marketing )
I'm just going by what Larry Fisher told me at NAB
But who tested what ..did SD tested different brand recorders compared
to the 788 , or did Lectro tested diff brand of recorders ?
R
My understanding is that Lectro supplied a number of different receivers and
transmitters to SD for a good period of time and SD did the testing. The
claim about the other recorders tested is basically that the 788 was RF
quieter than the other recorders out there they tested and did not appear to
be a sales statement....merely a reassurance that they did as good as or a
better job than the other manufactures. No accusations that some other
manufacture's machine was terrible. The new recorder is RF quiet, nothing
more nothing less. |
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| Larry Fisher |
| Posted: Sat May 03, 2008 2:44 pm |
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Hi Charlie and Roberto,
Here's all I know about various recorders, RF, etc. We tested a 744 a
few years ago because of range complaints and indeed found it RF noisy
at very close range, though still meeting government (FCC)
requirements. We tried various metal plates and tapes and gave up, as
the noise leaked out of many points, though the battery compartment
was the worst. Our only suggestion to clients was to separate the
receivers and the recorder and/or to tune to a quiet spot where the
recorder wasn't radiating. The problems were the bags aren't very big
and usable spectrum was disappearing.
At NAB the next year, I took a UCR411a around the show and physically
laid both antennas on running recorders and did frequency scans.
Cantars and Devas were very quiet and had only slightly more noise, if
any, than the show background. The 744 showed much more RF leakage.
Though not scientific, it did agree with what users were seeing.
We (Lectro) did not do any tests on the new 788 but were told by SD
that the units were much better and as quiet or quieter than other
recorders (no brand names). They described board layout procedures and
the use of a spectrum analyzer. We did not loan any gear to SD but
were told that they had rented (borrowed) every singe block of our
receivers to make sure there were no problems. They also used (I was
told) that they also tried various UM450 1/4 Watt transmitter to make
sure the units were not RF prone. To the best of my knowledge they
have not said that they were MUCH quieter than the competition. The
competition was already pretty good, particularly compared to some of
the crap that was being sold 5 to 10 years ago. Some of those units
would probably make a sound mixer sterile.
Bottom line: I think SD made a real effort to correct a problem and
did so. Lectro has zero business relationships with SD, just a 442 and
USBpre that we bought for listening tests through a dealer.
Best Regards,
Larry Fisher
Lectrosonics
On Sat, 3 May 2008 11:30:04 -0700, "Charles Tomaras"
<tomaras@tomaras.com> wrote:
Quote:
"-¦-R?b?rto¤" <~*u-¦-e-¦@l¤ess.com> wrote in message
news:s3bp1414sj8k8vn5ugjd5fre772vpbqq0n@4ax.com...
On Sat, 3 May 2008 09:37:23 -0700, schreef:
"-¦-R?b?rto¤" <~*u-¦-e-¦@l¤ess.com> wrote in message
news:9a4p14lajebairfnhenigqpo4h8fslv9sq@4ax.com...
On Fri, 2 May 2008 23:22:09 -0700, schreef:
new board design to achieve the quieting which is said to be far
quieter than all of the current competitive recorders that were tested.
Interesting. Do they have results that one can see , like different
models/brands and such ?
R ( or is it just marketing )
I'm just going by what Larry Fisher told me at NAB
But who tested what ..did SD tested different brand recorders compared
to the 788 , or did Lectro tested diff brand of recorders ?
R
My understanding is that Lectro supplied a number of different receivers and
transmitters to SD for a good period of time and SD did the testing. The
claim about the other recorders tested is basically that the 788 was RF
quieter than the other recorders out there they tested and did not appear to
be a sales statement....merely a reassurance that they did as good as or a
better job than the other manufactures. No accusations that some other
manufacture's machine was terrible. The new recorder is RF quiet, nothing
more nothing less.
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| Philip Perkins... |
| Posted: Sun May 04, 2008 8:40 am |
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I started this thread, so I guess I should say why. I had been using
block 21, 27 and 28 Lectros in various bag configs with a 702T, with
the mixer(s) between the recorder and the RX. I saw some RF
interference, but nothing I couldn't seem to get away with on normal
jobs. I recently got a block 25 wireless, roughly the same vintage as
my other wireless, and the receiver went nuts anytime I had the 702T
powered up in the same bag config. In my RX rack on the cart, or just
sitting on a table top in the same setting, this same RX behaved
beautifully. Wondered if the whole block was an issue, or I just had
bad luck with which specific freq I was on. Will experiment further,
good news on the 788, for those who can afford them.
Philip Perkins |
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| Noah Timan... |
| Posted: Sun May 04, 2008 9:11 am |
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On May 4, 10:36 am, jimmytuff... at (no spam) googlemail.com wrote:
Quote: Is the interference issue specific to using Lectro's rather than Audio
ltd's? Or are all radio receivers equally prone to suffering? I'm
thinking in terms of using Audio ltd rx on UK frequencies 854-860 mhz.
I'm in a lower part of the spectrum, but I haven't ever experienced
the problem with Audio Ltd 2000s and 2020s and the 744T. I
experienced it last week when I used Lectros in the bag with that
recorder for the first time.
.02 nvt |
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| Larry Fisher... |
| Posted: Sun May 04, 2008 1:33 pm |
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Hi Jim,
We are running various RF products through "no lead" soldering
processes right now. Results so far are good and easier than I
expected. We are shooting for the end of the year for re-introduction
to Europe with just the newest products. The SR and Venue receivers
are on the short list along with the SM series, the HM plug-on, and
the UT400 transmitters. No lead processing is not as much of a time
problem as are CE approvals and setting up GOOD servicing dealers.
Higher frequencies won't be a future problem as we are already doing
944 MHz in the states.
Best Regards,
Larry Fisher
Lectrosonics
On Sun, 4 May 2008 11:03:31 -0700 (PDT), jimmytuffrey at (no spam) googlemail.com
wrote:
Quote: Larry
I assumed it was not a specific to one brand (Lectro), issue. Good to
have clarification though. Unfortunately here in UK I can't find your
equipment as I believe you don't do our frequency range i.e. UK ch69
854-860 Mhz. Wish you did. The SR units seem like what we need. I am
reluctant to buy into analogue such as Audio 2040 and it all costs the
earth here.
Cheers
Jim |
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| Charles Tomaras... |
| Posted: Sun May 04, 2008 1:48 pm |
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"Philip Perkins" <spamiser at (no spam) yahoo.com> wrote in message
news:98b45f78-22f3-40bf-8f19-1b23a6d82f3d at (no spam) p39g2000prm.googlegroups.com...
Quote: good news on the 788, for those who can afford them.
I ordered one but I have no intention of paying for it...I'm going to put it
on a credit card! |
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| Noah Timan... |
| Posted: Sun May 04, 2008 1:50 pm |
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Hi Larry,
I should have disclaimed it by saying that my results are very
unscientific tests -- it's just the units that I have that were put
into play. My older Audio Ltds. have a very limited number of
frequencies available (either 2 or 32), and are on a different block
than my Lectro units. The Audios never had problems in proximity to
the 744T. I don't know if that's a design difference in terms of RF
shielding, or if I've just been lucky in terms of where the 744T
causes trouble and the narrow frequency band where my Audio Ltds
operate.
The Lectros I used were scanned in the bag with the 744T on, but even
after the scan we got a lot of hits at unreasonable range for what the
scan represented. (It wasn't in record mode, but I heard the hits
long before we started rolling). When I put the receivers on longer
cables and held them above my head, the problem went away (without
retuning), so after all I have read here, I was tempted to think it
was the recorder. That scenario, of course, caused the problem of
tying up one of my mixing hands (as well as probably making me look
like a buffoon). I do, however, prefer to use Lectros in the bag
versus Audios since the Audio receivers are a bit more delicate, so
I'm considering that the answer is probably your RF splitter fed to
the receivers in the bag, bussed to some dipoles clipped to the
shoulder straps of my harness. (Come to think, that'll probably also
look silly, but at least I'll have hands-free operation!)
Thanks for your input...I appreciate it!
Regards,
Noah Timan
On May 4, 7:13 pm, Larry Fisher <Lectroson... at (no spam) gmail.com> wrote:
Quote: Hi Noah,
The interference is not everywhere but is at multiples and sub
multiples of the internal clocks and data rates. Trace lengths and
ground plane spacings will modify the energy at each multiple. If you
do a scan with a receiver or a spectrum analyzer, you can find holes
in the radiation. Just make sure the recorder is in the operating mode
you will use in real time as it does make some difference. I thought
SD had some plots of their noise spectrum but I haven't looked
recently. On the same exact frequency, the Lectros and Audios should
have about the same reduction in range.
Best
LarryF |
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| ... |
| Posted: Sun May 04, 2008 3:42 pm |
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Larry
Cheers for the info
Jim |
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| Larry Fisher... |
| Posted: Sun May 04, 2008 6:13 pm |
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Hi Noah,
The interference is not everywhere but is at multiples and sub
multiples of the internal clocks and data rates. Trace lengths and
ground plane spacings will modify the energy at each multiple. If you
do a scan with a receiver or a spectrum analyzer, you can find holes
in the radiation. Just make sure the recorder is in the operating mode
you will use in real time as it does make some difference. I thought
SD had some plots of their noise spectrum but I haven't looked
recently. On the same exact frequency, the Lectros and Audios should
have about the same reduction in range.
Best
LarryF
On Sun, 4 May 2008 12:11:47 -0700 (PDT), Noah Timan
<dontwritemehereok at (no spam) yahoo.com> wrote:
Quote: On May 4, 10:36 am, jimmytuff... at (no spam) googlemail.com wrote:
Is the interference issue specific to using Lectro's rather than Audio
ltd's? Or are all radio receivers equally prone to suffering? I'm
thinking in terms of using Audio ltd rx on UK frequencies 854-860 mhz.
I'm in a lower part of the spectrum, but I haven't ever experienced
the problem with Audio Ltd 2000s and 2020s and the 744T. I
experienced it last week when I used Lectros in the bag with that
recorder for the first time.
.02 nvt
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| Charles Tomaras... |
| Posted: Mon May 05, 2008 3:20 pm |
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"johngooch" <jgoochmixer at (no spam) mac.com> wrote in message
news:1693d7da-2d88-445f-97f5-92d365248f0c at (no spam) w7g2000hsa.googlegroups.com...
Quote: Now the hard question.......If they figured out what was causing the
RF problems, can they retrofit existing 744ts to not emit RF?
I am guessing they can not and it is a complete re-tool of their
design. But it they could, i'd pay for it. It is the the pain of
being a niche market. In essence we are all beta testers for most of
the products we use. I grumble but I still applaud manufacturers for
keeping us on the bleeding edge!
john gooch
Who knows, since the size and utility of the first gen 7xx recorders has not
diminished, they are still a viable product for SD. Maybe in the future
there will be a 7xxA series with an internal redesign. Count me in as one
who would be happy to pay a reasonable at cost/labor upgrade for new guts if
they do in the future produce a 2nd generation of these recorders. I've
certainly learned to work around the emissions issues and for a great many
people working on carts, doing sound gathering or with remoted antennas it's
not an issue at all. |
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