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2008-04-22 19:46	Wireless Microphone - China Wireless Microphone Manufacturer	blog585
Wireless Microphone - China Wireless Microphone Manufacturer Wireless Microphone WebSite Link: http://www.chinese-microphone.com/Wireless-Microphones.html China GuangZhou TianTuo Microphone Manufacturing Co., Ltd WebSite: http://www.chinese-microphone.com/ Microphone Products are: Wireless Microphones, Conference Microphones, Headset Microphones, and Lapel Microphones, interview microphones, wired microphones, musical instrument microphones, drum microphones, teaching microphones, recording microphones, computer's USB microphones and microphone accessories and So on. Wireless Microphone: Buying Guide 1-800-222-4700 Forums | Careers | inSync News | Wish List | Order Status | Help / Support SEARCH SHOP BY BRAND Tech Support: Over 15,000 product support articles and factory- authorized service. Click Here » Customer Service: Shipping Policy Return Policy International Orders View All Topics Contact Us » Expert Center > Buying Guides > Microphones > Wireless Microphones > Buying Guide «Back to Buying Guide Menu Wireless Microphone: Buying Guide Wireless Mic: Buying Guide Wireless Mic: Tech Tips Wireless Mic: Glossary Wireless Microphone Topics: » Wireless Setup Basics » Wireless System Application Types & http://www.chinese-microphone.com/Wireless-Microphones.html raquo; The Truth About Diversity » UHF vs. VHF » What to look for in a Wireless Microphone The advantages of wireless microphone systems, both UHF and VHF, are obvious in terms of convenience and mobility, especially if you are an energetic performer, but naturally, there are always tradeoffs. This guide is designed to uncover some of the mysteries behind the operating principles of wireless systems. Sweetwater believes that the best customer is an informed customer. An understanding of the basic principles of wireless operation will help you work with your Sweetwater Sales Engineer to choose the perfect system that will satisfy your present and future needs. Wireless Setup Basics Setting up a wireless mic involves a few more steps than just plugging in and turning up. But, after you've done it a few times it will become an easy habit. The following will also help you decide which type of system you might want to purchase for your situation. Also, the following is very generic information. We always suggest that you follow the tips found in your owner's manual. Regardless of what type of transmitter you have, always be sure you start with a fresh battery. Battery life varies from system to system; check your manual. A good rule of thumb - If your battery has served more than half the listed life, replace it. Make certain your transmitter is off. Turn on your receiver. If your system has Automatic Frequency Selection, press the receiver's "Select" button. It will scan and locate a suitable frequency. Temporarily turn down the receiver's volume or level control. Turn on your transmitter. If your system has Automatic Transmitter Setup, press the transmitter's "Sync" button. It will lock on to the receiver's selected frequency. Check the receiver's LED or meter to confirm that it's picking up the transmitter. Turn the receiver's volume control up to a "normal" level. Now adjust the transmitter's audio gain. This is the key to getting a good sound and good levels! You might need a screwdriver for this. Sing or speak loudly into the mic and increase the gain slowly until the receiver's "RF Level" or meter occasionally flashes to indicate a peak during the very loudest moments. Do a walk-around through the performance area while observing the receiver's "Power" LED or RF meter. It should indicate sufficient reception in all areas of coverage. If you experience a dropout, reposition the receiver or its antenna for better reception. Simply stated, setting the proper input gain is the most important adjustment on a wireless microphone system. Set too low, the signal-to- noise ratio of the system will s uffer. Set too high, severe distortion and/or compression of the dynamic range will occur. Adjusting the transmitter input gain is very much like setting the record level on an analog tape recorder. It is important to consider the features and controls offered on any wireless transmitter that enable accurate gain adjustment. The transmitter-to-receiver distance has a major effect on the signal-to- noise ratio of a wireless system. As the transmitter moves farther away from the receiver, the overall signal-to-noise ratio grows worse as the transmitter signal gets weaker. When the system gets near the limit of its operating range, dropouts will become more frequent and a buildup of steady background noise (hiss) may be audible. Wireless System Application Types No matter what you do onstage, there's a wireless solution to your microphone needs. Here's a rundown on the available types of wireless mics. Handheld Microphone w/ Built-In Transmitter This is the perfect mic for lead vocalists. It's also great for stage situations in which a mic will be passed from person to person. Models such as the Shure ULX2/SM58 use the same capsules as popular vocal mics. Headworn Mic w/ Bodypack Transmitter Ideal for singing dancers, singing drummers, dance and fitn http://www.chinese-microphone.com/Wireless-Microphones.html ess instructors, and anyone who is active onstage. Headworn mics, such as the Sennheiser EW 152 G2, almost always have a cardioid or supercardioid pickup pattern, essential for rejecting bleed from onstage instruments. Lavalier Mic w/ Bodypack Transmitter A standard for public speakers and presenters, worship leaders, and stage actors. These mics are available with omnidirectional pickup patterns such as the Sennheiser ME 2, and also in cardioid versions like the ME 4. The Sennheiser EW 112 G2 is a great example! Clip-On Mic w/ Bodypack Transmitter Frees brass and woodwind players from the tyranny of the mic stand! Mount one on a djembe or surdo and set your percussionist free. The Samson Airline 77 Wind Instrument System has an integrated transmitter, eliminating the need for a bodypack. Instrument Cable w/ Bodypack Transmitter Guitar and bass players were among the first to go wireless onstage. And don't worry - the days of the Spinal Tap nightmare are long past! The Audio-Technica ATW-3110 system features a compact transmitter that stays in place no matter how much you duckwalk. The Truth About Diversity The term "diversity" is one of the most widely misunderstood concepts of wireless systems. As it applies to wireless microphone receivers, the term simply refers to the use of two antennas to eliminate "dropouts" caused by multi-path phase cancellations (multi-path nulls). Dropouts occur when the transmitter and receiver antennas are in a particular location relative to each other. Moving the transmitter or receiver to a different location can often reduce or eliminate the dropouts. Other objects that move around the room, like people’s bodies, also alter the reflected and direct signals and can make dropouts either more or less prevalent. The wavelength of radio signal carriers at VHF frequencies ranges from about 5 to 6.5 feet long. At UHF frequencies, the wavelength ranges from about 12 to 20 inches. The point is that the "dropout zone" (the location where a dropout occurs) will be larger at VHF frequencies than at UHF frequencies, so antennas have to be moved farther with a VHF system than with a UHF system to alleviate dropouts. This also means that locating and being able to identify a dropout zone during a walk test is a bit easier with a VHF system than with a UHF system. There are four types of Diversity designs. Following is a brief explanation of each: Passive Diversity: This is simply the addition of a second antenna to a single receiver, placed 1/2 wavelength or more away. This can be accomplished easily with an outboard combiner and a second antenna. Two combined antennas will gather more RF signal and can reduce dropouts to a small degree. Real-world tests have shown that there is no real improvement in the prevention of dropouts by simply using two antennas. Antenna Phase Switching Diversity: The primary advantage of this technique is small size, which explains why this method is used in compact receivers designed for field production. Two antennas are mixed to feed a single receiver, with a phase reversal switch added to the input of one of the antennas. Audio Switching Diversity: This approach uses two separate receivers, selecting the audio output of one of the receivers. It is quite effective at overcoming dropouts, but only provides a minor improvement in operating range. The switching action is usually triggered by comparing incoming RF levels and switching to the receiver with the stronger RF signal, which usually produces a better signal to noise ratio in multi-path conditions. This method is often called "true diversity," and is one of the more effective methods of reducing dropouts. Ratio Switching Diversity: This approach to diversity reception utilizes two separate receivers, sharing a common oscillator and audio circuitry. The audio outputs of the receivers are used simultaneously, being mixed by a "panning" circuit in a ratio controlled by the comparative RF levels at the receivers. The ratio combining process is similar to an audio switching diversity design. The difference between these two techniques rests in the fact that a ratio diversity receiver utilizes both receivers simultaneously, whereas an audio switching type uses only one receiver at a time. These systems can be prohibitively expensive and offer little advantage over a well- designed true-diversity system. DIVERSITY vs. NON-DIVERSITY In a setting such as a church or other situation where there are no obstructions between the transmitter and receiver and frequency coordination is relatively simple, it may well be to your advantage to have a VHF, non-diversity system. Your Sweetwater Sales Engineer can help you with frequency coordination. In order to discuss this subject intelligently, it is important to understand that no one characteristic of a circuit operates in a vacuum. That is to say, there are a number of other circuits whose functions operate interdependently. Sensitivity is one aspect of receiver performance to consider before making an assumption that a diversity design is superior by default. Another is the Squelch Threshold, or the level at which a receiver is muted when switching occurs. For example, if the signal from a transmitter d http://www.chinese-microphone.com/Wireless-Microphones.html ips to a level of 5uV due to operating range and multi-path nulls, which is not at all uncommon, a receiver that squelches at 7uV will shut down and mute the audio from this transmitter signal, no matter what sort of diversity circuitry is employed. A single antenna/single receiver design (non-diversity) will operate at lower input voltages prior to squelching and continue to operate and deliver usable audio. Therefore, It is always a good idea to check the sensitivity specification of any receiver along with the type of diversity circuitry being used in the design to get a good idea of how well the device might actually work. Naturally, your Sweetwater Sales Engineer can assist you with this and other vital aspects of wireless performance in choosing the right system for your needs. UHF vs. VHF This is another misunderstood area of wireless systems. It’s generally accepted that UHF has greater range due to higher power output, and is less susceptible to television interference. Again, there is truth to this but there are other factors to consider. Power Output For example, in the VHF spectrum from 174 to 216 MHz the maximum allowable transmitter output power is 50mW. In the UHF band maximum allowable transmitter power is 250mW. Higher output power from the transmitter helps overcome dropout problems and increases operating range, but the sacrifice is shorter battery life. The actual effective radiated power is heavily affected by the individual transmitter’s antenna, so a higher output power does not necessarily mean greater operating range. Most high-quality VHF transmitters produce the allowed 50mW, for reliable operating range and reasonable battery life. UHF transmitter output power varies much more widely from one brand to another than VHF units. The maximum allowance of 250mW in the UHF spectrum is useful when maximum operating range is the prime concern. 100mW is commonly chosen for UHF transmitters as a good balance between operating range and battery life. VHF & UHF Wireless mic systems generally operate in several bands from 150MHz to 216MHz, which includes the VHF TV channels 7 through 13, or in the 470MHz to 806MHz UHF band (TV channels 14 through 69). TV channels 60 to 69 (746 to 806MHz) are being re- allocated, as of the date of this writing, for other applications. In addition, the band from 470 to about 516MHz is also being re-allocated for public safety applications. The demand for more spectrum usage is increasing while the available spectrum for wireless microphones is decreasing. Above the TV band is another part of the UHF spectrum from 902 to 928MHz. This upper UHF band is a "general purpose" band being used by a multitude of different applications ranging from garage door openers and amateur radio, to home-use cordless telephones. Generally speaking, the 902 to 928Mhz band is not a good choice for wireless microphone systems, especially for professional use in traveling applications. Interference i s virtually guaranteed in this band. So again, it is unreasonable to assume that UHF is better by default. Choosing A Wireless Mic For Live Performance: When choosing a wireless mic for live performance, there are a number of factors to consider. Naturally, good sound quality goes without saying, but there are other equally important factors as well: The mic should be rugged and reliable in order to hold up to the rigors of nightly live performance and travel. It should be comfortable and easy to hold while performing. It should have good resistance to feedback. It should be able to handle high SPL (Sound Pressure Levels). Of the characteristics me http://www.chinese-microphone.com/Wireless-Microphones.html ntioned above, the mic's ability to resist feedback requires a little more in- depth discussion. Resistance to feedback is where the mic's polar pattern comes into play. The polar pattern determines the "listening area" of the mic. A cardioid or super-cardioid pattern tends to be more directional, picking up sounds from in front of the mic and rejecting sounds from behind (such as stage noise form monitors, amps, etc.). This will typically increase gain before feedback, which makes either pattern more desirable for live use. One mic with good sound and incredible gain before feedback, is the Shure Beta 58. Generally, the mic of choice for stage has been dynamic mics like the Shure SM58 or the Sennheiser MD835 , because they're rugged and can handle high SPLs (and ravenous roadies) since the diaphragm is more rigid than that of a condenser mic. The trade-off is slightly less response to transients resulting in a less detailed sound than with studio condenser vocal mics. Hoping to combine the best of both worlds by offering studio-quality sound in a hand held stage mic, a number of manufacturers have introduced a new generation of road- worthy condenser mics. Following is a list of handheld wireless mics to consider:Under $200 Samson Stage 5 VHS System Shure PGX2 PG58 Dynamic Samson Concert 77 UHF System $200-$500 Shure SLX2 Beta 87A Condenser Audio-Technica ATW-3141 $500-$900 Audio-Technica AEW-4240 Sennheiser EW 365 G2 As always, your Sweetwater Sales Engineer has a wealth of information and experience choosing wireless mic sets. Call 1-800-222-4700 today to get connected! WHERE DO YOU GO FROM HERE? Naturally, the discussion of wireless systems doesn’t end here. There are so many other factors to consider (such as image rejection and selectivity) but at least now you should have enough information to help you separate fact from fiction. The next step is to call your Sweetwater Sales Engineer at 1-800-222-4700 for the finer points of choosing the best wireless mic system for you. Shop for Wireless Microphones »» Home | Gear Reviews | Videos | Buying Guides | Glossary | Tech Tips | Show Reports | Publications | Featured Articles Sweetwater Deals! Sign up for weekly email offers: Unsubscribe | Learn More » About Sweetwater· Why Sweetwater · Our History· Customer Testimonials· Tour Our New Headquarters! Additional Services· Publications· Gift Certificates· Special Financing· Sell Your Used Gear Benefits & Policies· Free Shipping on Most Orders· Safe Shopping Guarantee· Shipping & Delivery Times· We Protect Your Privacy Customer Support· Track Your Order· Return Policy· Sweetcare 24/7 Support· More... Careers | Events & Seminars | Recording Studio | Trading Post | Download | Links | Press Releases | Contact Us Sweetwater Sound, Inc. 5501 US Hwy 30 W Fort Wayne, IN 46818 Get Directions Toll-Free (800) 222-4700 Local (260) 432-8176 Fax (260) 432-1758 Telephone hours:9-9 Mon-Thu, 9-8 Fri, 9-7 Sat EST Retail Store hours: 9-8 Mon-Fri, 9-7 Sat EST Current Sweetwater time is 10:21 AM © 2008 Sweetwater Sound Inc. All rights reserved. Please read our Terms of Use and Privacy Policy. Site Map Wholesale Wireless Microphone skomentuj

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Chinese Microphone - China Chinese Microphone Manufacturer	blog585	2008-04-22 19:46