Re: Sennheiser picks up were Lectro leaves off

Hi Matt,
This already is a lengthy post so I'm going to stuff my comments in
the body of your text.

On 15 Apr 2006 12:53:18 -0700, "Matt Hamilton" <matt@xxxxxxxxxxxxxxxx>
wrote:

I spoke with a Sennheiser rep at one point about the 50mW question a
few years ago. He basically said that it was all about the design of
the system and not as much about "my wattage is bigger than yours". He
was making the argument that a 50mW Sennheiser's performance would
match a 100mW system's performance because it was all in the design. I
don't know how much to trust this since he was really trying to
convince me to look at the Sennheiser wireless at the time, but it
seems to make sense.

Keeping in mind that a rep is not the official word of a company or
the company's engineers. What else can a rep say. "More power works
better" certainly wasn't an option.


I know Lectro makes European versions of everything, so they could
probably give a "both sides of the ocean" response to clear this up.
It would be worth finding out since a 50mW system should be less of a
power draw and would have extended battery life. Of course, that
depends on a lot of other things, too. The size looks nice.

The 50 mW, lower deviation European units do not work as well as the
100 mW higher deviation US units. If they had worked as well we would
have done all new designs to meet European (universal) specs. I will
say the differences are not major. The wider deviation in the US gives
3 dB or more extra noise suppression and the added power is good for
40% of range.


There is a limit to the "more wattage is better" concept, though.

I agree. Anything above 50,000 Watts is beginning to be ridiculous.

I
can't remember if it was Larry at Lectro or not, but I spoke to someone
from Lectro a while back about a 250mW transmitter. He said that you
get more distance with 250mW, but you also get more RF "splatter" with
the extra power. So, you are kind of trading off certain things. For
instance, you can't have as many transmitters on the same block if they
are all at 250mW because they bleed all over each other. Efficiency of
the transmission goes way down. You also can't have 100mW systems
anywhere near the same 250mW blocks because the 250's will blow the
100's out of the water.

No. You are only talking about 4 dB more power and about 60% more
range compared to a 100 mW unit. In a bag system, you will need to
increase separation by 60% for the same level of interference.

Lectro has previously advised against using a 200 transmitter in a bag
with a bunch of 201 receivers on the same block because the front end
of these receivers are not as "tight" and can open up for a transmitter
even if it is on another frequency. This bedeviled me a few times on a
shoot where I would forget to turn off a transmitter prior to putting
it into my bag. I'd start getting all sorts of crazy hits on all the
other receivers until I remembered to turn off the transmitter. I
don't have experience of this level with the 411's, but they are
recommended for situations where you have to transmit and receive in
the same bag. They have a tighter front end and can live happily in a
bag with transmitters and receivers on the same block. Both are 100mW
systems, but perform differently. So, buy your systems according to
what your end use will be. A call to Lectro might be in order.

If you add all this together, it seems to point to the possibility of
using 50mW with a tight front end to achieve similar performance to a
100mW system with a looser front end because the receiver isn't
"fighting" as much to find the signal. Maybe this is true of the newer
Sennheiser systems?

The Sennheiser systems must be even wider than they were if they are
now switching through 36 MHz. Unless the front end tuning changes with
the selected frequency, the wide switching range results in a wide
front end. The single frequency 195's were the last of the truly
narrow front ends. Other single frequency receivers were narrower than
today's PLL based systems. Once again, what can a salesman say.

The antennas on the receivers play a large part in range as well.
Shark fin antennas help a lot. I knew a mixer who used a set of
Sennheiser EW100 dual diversity rack mount receivers (the least
expensive systems Sennheiser makes) with shark fins at the Olympics one
year and achieved some pretty substantial range from within a buidling
to a person speaking outside in front of the building. Another mixer
told me they "sucked" because he'd been using them in a basement full
of pipes and had only gotten a few feet before drop-outs. Besides the
obvious reflection problems, he was using the non-diversity setup with
the screw-on antennas.

Absolutely true.

The point of all this rambling is this: Until you're in the situation,
you just don't know. There is no test that is meaningful. I've seen
the transmission signal strength fluctuate on the 201 receiver (100mW)
when I was sitting 10 feet away from someone, behind an interviewer,
behind the camera on a tripod, behind a camera operator, behind a light
stand.

Again. dead on.

Obviously, this is not ideal, and line of sight is preferred. The
operating range of a 100mW system can be radically reduced by the
situation. What I do know is that I can call Lectro and discuss my
setup with the people who built the equipment. I like that. I also
like the 201 and 411 receivers because I can actually look down and see
what is happening on the display at that specific point in time, see
that I'm getting close to losing signal BEFORE it happens, and move the
receiver accordingly to correct the problem. The Sennheiser 3041's do
this as well. This assists me in my job because I am getting
meaningful feedback about the situation as it happens.

Just some things to consider. I'm sure other folks can post similar
experiences.


-Matt

Good post. Open minded with real experiences.
LarryF
Lectro
.

Relevant Pages

  • Re: Sennheiser picks up were Lectro leaves off
    ... convince me to look at the Sennheiser wireless at the time, ... I know Lectro makes European versions of everything, ... Lectro has previously advised against using a 200 transmitter in a bag ... of these receivers are not as "tight" and can open up for a transmitter ...
    (rec.arts.movies.production.sound)
  • for sale Sennheiser Evolution Wireless
    ... x Sennheiser EW 100 bodypack transmitter Block B US$200 ... Receivers are same size as transmitters. ...
    (rec.arts.movies.production.sound)
  • WTB Comtek or other reliable IFB
    ... Looking to add one transmitter and 3 or 4 receivers to my bag. ... be in good working order. ...
    (rec.arts.movies.production.sound)
  • Re: Comteks For Sale
    ... 11 x Soft Comtek carry cases for transmitter and receivers. ...      1. ... jack socket input, 9v battery power, LED battery / RF indicator and a ...
    (rec.arts.movies.production.sound)
  • Re: VHF radio mic problems
    ... I'm guessing there will be trimmers in the receivers for fine-tuning the ... physical movement of the antenna wires or body packs. ... If you have "line of sight" from transmitter to receiver, ...
    (rec.arts.theatre.stagecraft)
Loading