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Old June 14th, 2004, 09:35 AM   #1
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True Diversity vs. non

Anyone have experience comparing true diversity UHF systems to non-diversity UHF systems? I'm in the market for a wireless system and was pretty sold on the Senn. G2 ENG kit when available. In another thread, there was a link to a guy that did a comparison between the Senn G2. system and a Sony UWP-C1 system. Just from interference alone, I thought the Senn. sounded like crap, but the Sony didn't drop out at all. I'm thinking now that maybe I should be looking for a diversity system, but I don't know. Just wondering if the test mentioned above was normal or not. Thanks.
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Old June 14th, 2004, 12:26 PM   #2
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I am in the same boat! I can't get over how good that Sony sounded...Anyone know about how much range this sony has? I shoot both indoor and outdoor weddings where my AKG pr40 has been alright up until yesterday when all I got was shhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!! Luckily I always have backup for audio and video bcs. that would have SUCKED! I have called AKG twice today already and left messages, haven't actually spoken w/ anyone yet.

Anyway, I would like more range than 50ft. in a church and 15-20ft. outside...will the sony do it for me? I really don't care for so many channels and what not...just want RANGE!
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Old June 15th, 2004, 12:29 PM   #3
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Everything else being equal, diversity receivers are better.

If you were using the system in the middle of the dessert, with no structures around, both systems would perform equally well. But where there are conductive structures in the area (walls, trees, tripods, etc.), then the reflecting signals can cancel each other out at certains postions. Have you every seen your celluarl signal meter get stronger just by moving you phone a few inches? It's called multi-path distortion. It usually repeats at about 1/2 the wavelength of the frequency. At 900 MHz, that's about every 6-1/2 inches.

Buy having two antennas to choose from (and the receiver can make the choise thousands of times per second), the receiver is assured of never having both antennas at a cancelled our (or "null") position. So, diversity receivers solve multi-path distortion issues. However, it doesn't really increase the system range.
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Old June 15th, 2004, 05:55 PM   #4
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Dan, do you recommend any particular brand or system that has diversity? Audio Technicas look nice, Sony's too, but there's Samson and Azden and AKG and Shure, etc...lots of different systems with lots of different price tags. I've done so much reading on this issue I'm going to throw up, but it doesn't do much good without actually trying them out.
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Old June 16th, 2004, 07:58 AM   #5
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No Bobby, I don't have any recommendation. I've been using an AKG PT40 system and it's working fine for me. But I don't push the range capability of the thing at all. It's a low cost option for light users like me. The Sony looks pretty good to me, based on reputation, batteries, size, weight and ease of mounting to a smaller camera (via the hot shoe). Of course, the Senn Evo gets consistently good reports from users.
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Old June 16th, 2004, 12:41 PM   #6
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Ok. I'm just bummed the Senn. systems aren't true-diversity.
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Old June 17th, 2004, 06:23 AM   #7
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I would like to point out that comparisons of different wireless systems can be VERY easily compromised (and even skewed) unless performed by a trusted engineer under carefully controlled conditions.

For instance, Was the Senneiser on a known clear frequency? Was that frequency tested for interfering traffic both before and after the comparison was done? Were the two systems in the same frequency band and were they checked for intermod interference?

What was the physical separation between the two transmitters? How was the physical position of the receivers selected? Were other positions tested? What kind of room was the test performed in? How many locations were tested?

While it is true that a true diversity receiver offers better dropout protection against signal strength nulls caused by reflections than non-diversity systems, they do not, in any way, improve audio performance. It is also true that a non-diversity system can perform and sound better than a diversity system.

There are many types of diversity systems:

A TRUE diversity system is one with two actual rf receivers, each connected to their own antenna. Which receiver is being output ant any given time can be determined by a variety of factors within the receiver.

Then there are several pseudo diversity receivers that switch or mix the two antennas into a single receiver. These systems are less expensive to impliment, but do not work as well as true diversity systems.

Sony's is described as a "space diversity" system. I am very suspicious of that term. The "space" could mean the mere distance between the two antennas which would mean nothing.

I am puzzled and amuzed by all the speculation here about these systems, and recommendations to buy a wireless mic at this web site or that photo shop (??) when professional help is available. Even if it costs you an extra 2%, isn't it worth it to have the security of professionals that can not only help you decide, but also stand behind their sale and support you afterwards?

I would not base my choice of systems on a comparison from an unknown source. Go to a professional audio dealer and get some experienced assistance with your purchase.
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