Microphones 101 B: Pickup Patterns

Directional Properties

Every microphone has a property known as directionality. This describes the microphone's sensitivity to sound from various directions. Some microphones pick up sound equally from all directions; others pick up sound only from one direction or a particular combination of directions. The types of directionality are divided into three main categories:

  1. Omnidirectional
    Picks up sound evenly from all directions (omni means "all" or "every").
  2. Unidirectional
    Picks up sound predominantly from one direction. This includes cardioid and supercardioid microphones (see below).
  3. Bi-directional or figure-of-eight
    Picks up sound from two opposite directions.

***The following graphs are called polar patterns.

Omnidirectional

Uses: Capturing ambient sound; Situations where sound is coming from many directions; Situations where the mic position must remain fixed while the sound source is moving.
Notes:

  • Although omnidirectional mics are very useful in the right situation, picking up sound from every direction is not always desired. Omni sound is very general and unfocused - if you are trying to capture sound from a particular subject or area it is likely to be cluttered by other sources.
  • Omnidirectional microphones have no proximity effect*.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Omnidirectioal

Cardioid

Cardioid means "heart-shaped", which is the type of pick-up pattern these mics have. Sound is picked up mostly from the front, to a lesser extent the sides, and minimally from the rear.
Uses: Emphasizing sound from the direction the mic is pointed while leaving some latitude for mic movement and ambient noise. Controlling feedback.
Notes:

  • The cardioid is a very versatile microphone, ideal for general use. Handheld mics are usually cardioids.
  • Cardioid mics have proximity effect.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Cardioid

Supercardioid

This is the cardioid or "heart shaped" pattern that picks up less from the sides at the expense of some sensitivity to the rear.
Uses: When more directionality than the cardioid is desired. Can be more effective against feedback.
Notes:

  • Supercardioids have more proximity effect than cardioids.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Hypercardioid

Figure-of-Eight

Picks up sound equally from two opposite directions.
Uses: Figure-of-eight microphones have uses in various stereo and ambient techniques. They also work well when capturing two people facing each other (like across a table). The very-low side sensitivity can be helpful controlling feedback and leakage. The pronounced proximity effect is often used when more “fattening” is desired (guitar amps and vocals).

Notes:
Figure-of-eights have more proximity effect than supercardioids.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Bidirectional

Variable Pattern
Some mics allows you to adjust the polar pattern continuously from omnidirectional to figure-of-eight by turning a knob on the front of the microphone.


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Phone: 800-762-9266 Ext. 211 · Fax: 440-248-4902 · E-mail: sales@cadmics.com
Used by permission. All Rights Reserved.

Microphones 101 A: Types of microphones

Dynamic Microphones
There are two basic types of dynamic microphones. These are moving-coil dynamic microphones and moving-ribbon dynamic microphones.

Moving-coil Dynamic Microphones

Moving-coil dynamic microphones are versatile and ideal for general-purpose use. They use a simple design with few moving parts. They are relatively sturdy and resilient to rough handling.

They are robust, relatively inexpensive and resistant to moisture, and for these reasons they are widely used on-stage. They are usually better suited to handling high sound pressure, such as from close-up vocals, certain musical instruments, and amplifiers. They generally have no internal amplifier and do not require batteries or external power.

How Moving-coil Dynamic Microphones Work

When wire is moved within a magnetic field a current is generated in the wire. Using this induction principle, the dynamic microphone uses a wire coil, magnet, and a thin diaphragm to capture the audio signal.

The diaphragm is attached to the coil. When the diaphragm vibrates in response to incoming sound waves, the coil moves backwards and forwards past the magnet. This creates an electrical current in the coil, which is channeled from the microphone along wires.

Moving-ribbon Dynamic Microphones
CAD Mics: Trion 7000

Moving ribbon dynamic microphones are generally more fragile than their moving-coil cousins and usually spend more time in the studio than on stage. (However, many Trion 7000s have been seen on several high-profile tours.) Ribbon microphones have a mellow sound of their own and work well on brass instruments, guitar cabinets, and other aggressive sources.

How Moving-ribbon Dynamic Microphones Work
Like the moving-coil dynamic microphone, the moving-ribbon dynamic microphone utilizes induction. However, instead of a coil of wire, a thin corrugated aluminum ribbon is suspended in the magnetic field. As this ribbon vibrates sympathetically to impinging sound an electrical current is generated in the ribbon.

Condenser Microphones

CAD Mics:Trion 6000, Trion 8000, C195, GXL2200, GXL1200, GXL2400, M179, M177, M9, e60, e70, e100-2, e300-2, ICM417, CM100, ST100, MG115, MG120

Condenser is a legacy term meaning capacitor, a device that stores energy in the form of an electrostatic field. Although the term is obsolete in engineering it is still used to describe microphones that use a capacitor to sense acoustical energy.

Condenser microphones tend to be more sensitive and responsive than dynamic microphones, making them useful for capturing subtle nuances and intricate detail. They are not always ideal for high sound pressure work as their high sensitivity can cause overload distortion in some mixers and preamps.

How Condenser Microphones Work

A capacitor consists of two conductive plates near each other. In the condenser mic, one of these plates is made of a very thin, light, flexible material and acts as the diaphragm. The diaphragm vibrates in the presence of sound waves, varying the distance between the plates, which varies the capacitance.

A bias voltage is required across the capacitor to sense this change in capacitance. This voltage can be supplied internally by a fixed electrostatic charge or externally.

As the capacitance changes so does the voltage across the capacitor. This voltage can be sensed by a vacuum tube or a field-effect transistor. In either case, power is needed to run the circuit. This power can be provided by internal batteries, an external power supply, or in the case of some CAD equitek microphones, both.

Phantom Power

Phantom power (labeled as +48 V or P48 on some audio equipment) is a method that sends DC power through microphone cables. It is called "phantom" powering because the supply voltage is effectively invisible to balanced microphones which do not require it, e.g. most dynamic microphones.

It is best known as a common power source for condenser microphones, though many active DI boxes also use it. Stand-alone phantom power supplies are available, but usually they are conveniently integrated into mixers, microphone preamplifiers and similar equipment.


© Copyright CAD Professional Microphones · 6573 Cochran Rd. Bldg. I · Solon, Ohio 44139
Phone: 800-762-9266 Ext. 211 · Fax: 440-248-4902 · E-mail: sales@cadmics.com
Used by permission. All Rights Reserved.

Lectrosonics: "The Sky is NOT Falling"

There are currently two issues of concern regarding changes to allocation of RF spectrum in the UHF range.

They are:

  1. Auctioning of the “700MHz band” (698-806MHz). As of February 17 2009, this portion of RF spectrum will be available to be used by the companies that won the auctions, and will no longer be available to Part 74 users (i.e. wireless microphones).
    • At the same time, analog TV stations will shut down and only DTV stations will be in operation. Because the 700MHz band will no longer be available to TV broadcasters, the few that are left will have to move to a lower range.
    • Thus, our blocks 27, 28 & 29 will have new (as of yet unknown) transmissions operating, while our blocks 21-26 may have a few new DTV channels when compared to today, depending on the local market.
  2. The FCC has approved the development of unlicensed consumer products that will use the “white spaces” (remaining unused spectrum between existing TV transmissions). Here’s what that means
    • These new devices will be required by the FCC to employ “Spectrum Sensing” technology that will determine what, if any, other users may be present in the RF spectrum, including TV transmissions and wireless microphone systems, among others.
    • These devices will also use a geo-location system (GPS) along with a database f known signal sources, such as TV broadcasts and high-profile wireless mic users to avoid interference.
    For a summary of the recent FCC rulings, download this PDF

What This Means

  1. Starting in February of 2009, there will be fewer TV stations in operation overall. This is because today, many stations are running redundant NTSC (analog) and DTV broadcasts. After February, 2009, they will only run their DTV broadcasts. Not only this, but DTV allows for multiple program channels to be embedded within a single DTV broadcast carrier. There is little financial incentive to add transmission channels at this time.
    • Please note the tables in the sidebar at right showing some examples of major metro markets and the available white space spectrum now and after February, 2009
  2. Lectrosonics makes high-powered systems, from 50mW to 250mW, with the standard units at 100mW. Thus, we already have a major advantage over systems with low-powered transmitters. Also, all of our transmitters have isolated outputs, thus using higher power, as we do, is not the problem (intermodulation products) as it is with competitor’s units that are not isolated. Bottom line: our systems will operate very well even with a fair amount of broad-band noise.

However, it will not be legal for us (or any manufacturer) to make and sell transmitters above 698MHz following February 17, 2009. In November of 2007, we announced to our dealers that we would cease stocking any transmitters in blocks 27, 28 and 29. However, these blocks will be available only on a special-order, non-returnable basis through the end of 2008. In addition, we have added three blocks at the low end of the spectrum (blocks 470, 19 and 20) so that spectrum lost at the high range can be compensated for on the low end. In addition, we will be adding products in the 944-952MHz range, including Venue, IFB, SM Series, UCR401 and SR.

Keep in mind that the first 68 frequencies available in block 27 will continue to be legal. If you are using block 27 systems, you may NOT need to do anything.

For those customers who would like to convert their block 27, 28 or 29 systems to lower blocks, please consult this PDF price table. This applies only to current products and to those products purchased new within the last 5 years from an authorized dealer.

Conclusions

  1. The sky is not falling (remember Y2K?). Wireless mics in the UHF band will not be rendered useless within the next few years. Existing and foreseeable-future wireless mics, particularly those made by Lectrosonics, will be fully operational for years to come. Yes – there may be some challenges but mostly it will be about learning and adapting to the new RF spectrum.
  2. Although the FCC requires the 700MHz band to be "vacated' as of February 2009, it is unrealistic to expect that all users of low-powered devices (wireless mics) will stop using their current systems. It is very likely that most wireless mic users in this range will continue to operate illegally for some time. Licensed, legal, part 74 users such as broadcast stations will have to cease operation in the 700 MHz band. Manufacturers of part 74 devices will have to cease manufacturing, importing, or even shipping units that operate in the 700 MHz band. Commercial development of this band will begin in the large metro areras first, then work its way out to the further reaches of the country, the same way that cellular coverage did in the 1990s.
  3. Lectrosonics, will, as required by the FCC, cease manufacturing and selling blocks 27, 28 and 29 for the US market at the end of 2008. To convert your systems in these blocks to lower blocks, consult this PDF pricing table.
  4. No one currently knows what will happen in the 470 to 700 MHz range. If and when the consumer "white space devices" hit the market (probably starting at the end of 2009 or later), the UHF band will be similar in terms of congestion to the way the 2.4 GHz band already is today. In other words, it will be workable with proper planning, good system components and good system design.

Lectrosonics is very concerned about these issues, and we hope to do everything possible to make you aware of what is happening and help you with the transition. If you have any questions, please don’t hesitate to contact us.

Lessons in mixing drums: on a StudioLive

PreSonus is introducing a new digital console. It's the first small mixer (at 16 channels) that I've seen that looks like it's been really well thought out. It's got both studio and live features on it, and it sure looks like a winner.

John Mills talks about it in this raw video footage. The session here is more about mixing drums in church than about the mixer, but it's still interesting.

AT's Solution: Ultra Wideband (UWB) Technology

This is Audio Technica's proposal for dealing with the white space issue: Ultra Wideband wireless transmission: using a "a series of short nano-second pulses which occupy an instantaneous bandwidth of 500 MHz,:" they utilize the 6.4 GHz band. Because of the high band and low RF power (40 nanowatts), there are some severe distance limitations. But this is brand new technology, and it's a solution! Hats off to AT for the new technology.

This is their press release:

Audio-Technica has partnered with Multispectral Solutions, Inc.® (MSSI®), the industry leader in the development of Ultra Wideband systems for communications, radar and geo-positioning, to introduce this new application of UWB technology.

A-T’s SpectraPulse Ultra Wideband wireless microphone system represents the first commercial sound implementation of UWB technology, which has recently been licensed for commercial use by the U.S. Federal Communications Commission (FCC). Ultra Wideband technology allows the wireless transmission of data in extremely short-duration pulses over a wide spectrum of frequencies. Instead of utilizing conventional channels and carrier frequencies, UWB technology uses a series of short nano-second pulses which occupy an instantaneous bandwidth of 500 MHz within the 6 GHz frequency spectrum.

The signals, in precisely timed sequences, result in the reliable transmission of information near noise-floor levels. The “decoding” of these pulses requires the specialized technology incorporated into the SpectraPulse system – making SpectraPulse inherently secure and preventing signal interception by other wireless systems. For a higher level of security, Audio-Technica offers an optional encryption package that meets the NIST-approved (National Institute of Standards and Technology) AES 128-bit encryption standard developed by the U.S. government for securing sensitive material.

This press release is from AT's website.
AT's white paper on the technology is here.
Wireless for conference room application is shown here.

FCC Rules for NEW TV BAND DEVICES:

What This Means For Wireless Microphone Users
November 18, 2008


The FCC has finally released its rules allowing a new class of unlicensed consumer electronic products to operate in locally unused TV channels. These have previously been referred to as white space devices (WSD) but are now called TV Band Devices (TVBDs). They will mainly be used as broadband access devices.
TVBD are categorized as:

1) Fixed
These are allowed to operate with effective radiating power up to 4W on channels 2-51, with the exceptions of channels 3, 4, and 37.

2) Personal/Portable
They are restricted to channels 21-51, and are also not allowed in channel 37 (reserved channel for radio astronomy and medical telemetry). They are limited to 100mW operating power or 40 mW if operating in a channel adjacent to an active station. This moderate power will reduce their range and therefore the possibility to cause interference.

Licensed operation of wireless mics takes precedence over TVBD. TVBD must coordinate around active licensed wireless mic systems.

The rules include several safeguards to avoid interference to wireless microphones:

  • Spectrum Sensing
TVBDs must include the ability to listen to the airwaves to sense wireless microphones (in addition to TV stations). Until they can demonstrate through “proof of performance” that they can reliably sense wireless mics and avoid causing interference they must also use a:
  • Geolocation/Database system
TVBDs must use location sensing in conjunction with a database of registered broadcast license assignments. The database will also include a list of protected areas for wireless microphones such as entertainment venues and sporting events. TVBDs must first access the database to obtain a list of permitted channels in the area before operating. A TVBD that lacks this capability can operate only under the direct control of a TVBD that has it.
  • Reserved channels
Personal/ Portable devices will be barred from channels 14-20 (470 – 512 MHz). In addition, in 13 major markets where certain channels between 14 and 20 are used for land mobile (municipal and public safety) operations, two channels between 21 and 51 will be reserved and available for wireless microphones. These will be the first open (non-TV) channels above and below channel 37.

This means, at minimum, 16 wireless systems (8 in each TV channel) can be used simultaneously in any venue. When using our equipment with high linearity (extreme suppression of harmonic distortion known as intermodulation) such as our 3000 and 5000 series equipment, the number increases to at least 20 systems (10 in each TV channel). Protected areas will be able to operate many more channels.

Multi stage and studio properties can also effectively increase the number of systems in use through:

1) Physical distance and transmitter output power management


This can be augmented by a balance of other techniques such as shif
ted coordinated frequency sets, zone isolation (natural or enhanced shielding between rooms), directional antennas, and filtered distribution systems.

2) Time multiplexing:

Using systems in different rooms at different times

The anticipation of these changes has caused a great deal of anxiety for many customers. However, when you choose Sennheiser, you not only get great hardware, you get service and support. To help manage customers through this transition and assure they can purchase with confidence, we will be introducing several new service and support programs. In the meantime, we invite you to register at our website, www.sennheiserusa.com/spectrumreallocation, for a free initial consultation. A Sennheiser representative will contact you, assess your current list of equipment and make recommendations to ensure reliable operation of all your wireless audio equipment.

Feel free to contact me with any questions. Thank you for your continued support.


Sincerely,
Joe Ciaudelli
Sennheiser Electronic Corp.
One Enterprise Drive
Old Lyme, CT 06371
860-434-9190, ext. 508


What’s happening with 700 MHz?

The FCC ruling yesterday really took most of us inside the Pro Audio industry. There was widespread expectation that the FCC would make a ruling on the now-ancient-history subject of 700 MHz, something to the effect that “It’s now illegal to use these frequencies.”

They didn’t.

I’m told by industry insiders that there is a proposal out there to that effect, but that the proposal has not been implemented. (What did happen, is that the big winner – Verizon – has had some hurdles removed that allow the FCC to accept their 28 Billion dollar payment and give them the licenses to use those frequencies.)

We all expect that they will make this decision sooner or later, and that wireless mics will eventually be disallowed in that frequency group.

But they have not yet made that decision.

And it may take time to make that decision. It will take time to implement that decision. And it will take time, I am told, for the technologies that require that decision to be developed.

Yes, the 700 MHz band has been sold. The new owners paid a lot of money for it. But they are not yet using their new purchase. In fact, they can’t yet.

The technology that will be used there has not been developed, licensed, manufactured or sold. In fact, it may not be entirely invented yet.

When that technology is implemented, many professionals are thinking that it will be something akin to cell technology: towers and high-powered broadcast signals blanketing the country. Assuming that this is the direction that they go, their high-powered signals will completely overwhelm the poor wireless microphone in your sanctuary or portable system. The rule won’t be necessary: mics will cease to work.

So there are two dates looming over us: the day that they tell us to stop using the frequencies, and the day that the frequencies cannot be used.

There are a lot of wireless users that will stop using their 700 MHz mics when the FCC says to. But I’ve heard from a number of individuals who say, “I’m going to keep using mine until they get the new technology in place. I have no interest in selling them!”

Indeed, the FCC appears to have no interest in policing the 700 MHz bandwidth for 50 milliwatt violators, so it appears that they will get away with it just fine.

The bottom line: don’t throw out your 700 MHz wireless just yet. It could be useful for a good long time yet.

FCC White Spaces Decision Kicks Off the Next Wireless Revolution

By Priya Ganapati Email

Television static is now broadband gold.

The Federal Communications Commission's decision to open up the 'white spaces' spectrum to unlicensed devices could usher in a new telecom revolution, say analysts.

Like WiFi, the availability of free, unregulated spectrum could create new technologies and new markets, bringing superfast wireless connectivity to the masses. Unlike WiFi, it could also put pressure on wireless carriers.

"All the PR spin and FUD (fear, uncertainty and doubt) failed in the face of physics and the ground reality of engineering," says Sascha Meinrath, research director of the wireless future program at the New America Foundation, a non-partisan public policy think-tank.

"Opening up white spaces will lower the cost of communications by facilitating new technology, software and devices is an enormous win for public interest," he says.

AT A GLANCE:
White Spaces Winners

Intel: The company's chips could power many of the new devices on the white spaces spectrum.

Google: New services from Google could be offered on the new spectrum. Google could even end up becoming a broadband service provider, perhaps as part of a consortium.

Motorola/Philips/Dell: They are likely to create the hardware and the devices to access the broadband services on white spaces.

Consumers: More innovative products, more wireless choices, and higher wireless data speeds. Also, the use of white spaces could finally usher in the era of seamless roaming across technologies.

White Spaces Losers

Verizon/AT&T/Comcast: These companies have paid billions over the years to gain exclusive rights to the spectrum. Now they will have to fight new entrants who have no legacy costs to worry about.

Professional Audio Equipment Manufacturers: These companies, which have so far operated in the white spaces, will have to spend more to create equipment that will work in different areas of the spectrum. They will also have to spend more on testing their devices to avoid interference.

'White spaces' refers to the unused bits of spectrum between UHF television channels, which will no longer be needed when the United States abandons analog television broadcasting and goes all-digital in February, 2009.

But just how to use that spectrum was a hotly-contested battle that pitted technology companies against broadcasters and wireless audio equipment manufacturers.

Wireless microphones and other equipment used by broadcasters and event producers already use some of this spectrum, so those groups resisted the idea of letting unlicensed devices onto their airwaves, willy-nilly.

The FCC's latest decision means technology companies such as Google, Intel Motorola, Phillips and Dell -- which lobbied to "free the spectrum" so they could build data services on it -- will emerge as big winners.

Update 11/06: Dell has said it plans to launch white spaces capable laptops

Telecom carriers such as Verizon, AT&T, Sprint and Comcast will feel the pain and be forced to adapt to a new reality, say analysts.

Verizon and AT&T have paid billions over the last few years for exclusive chunks of spectrum. Also, Sprint and Clearwire are creating a WiMax network that could also be threatened by white spaces-based broadband.

White-space frequencies are unlicensed, which means any company can use the spectrum. By contrast, wireless carriers have exclusive, licensed access to the frequencies that their phones use.

"White spaces could be a friend or foe of existing carriers," says Paul Gallant, an analyst with research wealth management firm The Stanford Group. "It might end up enabling carriers to enhance their retail offerings, or it could be used in completely new ways to undercut the existing business models."

Sprint declined to comment.

White spaces have been coveted by technology companies for their potential. The spectrum will allow wireless signals to travel two to three times farther than WiFi signals can today, including through obstacles.

Allowing for unlicensed use of white spaces means consumers will see a new generation of wireless broadband devices, said Craig Mundie, chief strategy officer for Microsoft, in a letter to members of the House of Representatives a few days ago.

It will enable low wireless broadband service in rural areas, self-forming mesh networks capable of routing traffic at speeds of 20 megabits per second and above within the mesh; and wireless distribution of content throughout the home and among devices, said Mundie.

That's exactly what consumers need today, agrees Meinrath. "All those problems of diversity on the airwaves and access to internet broadband connectivity are predicated on the artificial scarcity of airwaves," he says. "They will be alleviated."

The future of communications is in seamless roaming across not just networks but also technologies such as wireline broadband, WiFi and cellular networks.

"The devices of the future will allow you to completely un-tether yourself," says Meinrath.

Already Google has applied for a patent that would allow the company to create such a device.

Chip companies such as Intel are also likely to profit from opening up of white spaces. Intel could potentially develop chips that can ride over white spaces, much like the WiFi and WiMax-enabled chips it produces today.

The move could also mean that companies such as Motorola, Phillips and Dell could create new mobile devices that could become alternatives to smartphones or companions to notebooks.

For telecom service providers, it will be the beginning of a new world. Broadband connectivity over white spaces could change the telecom landscape much like WiFi did a few years ago.

Existing service providers will have to evolve fast or find themselves sinking as newer players, probably a consortium led by Google, enter the market.

"The key question is, who is going to pick up the ball and run with it?" says Gallant.

Meanwhile Cablevision is building out a mobile broadband service in New York using unlicensed spectrum that's not white space, says Gallant. If Cablevision's experiment succeeds Comcast, Verizon and other service providers could end up embracing white spaces.

As for Verizon's $4.7 billion winning bid earlier this year for the 700-MHz spectrum, it won't be an investment they are likely to regret.

"Verizon knew exactly what they were getting with that spectrum," says Gallant. "White spaces is just the opposite. It is very risky and may be hard to create a business model that will be truly successful on it."

from Wired magazine.

Airwaves Battle Pits Dolly Parton Against Google

SAN FRANCISCO — Tuesday marks the end of a battle that has lasted for more than two years, with each side predicting apocalyptic consequences should it lose.

Not the fight for the presidency. The one pitting Google against Dolly Parton.

The titan of Silicon Valley and the queen of Country are two of the many combatants in a high-tech dispute over precious slices of the nation’s airwaves. The issue comes to a head on Election Day, when the Federal Communications Commission votes on a proposal to make a disputed chunk of radio spectrum available for public use.

Google, Microsoft, Hewlett-Packard and other technology companies say the spectrum could be used by a whole new array of Internet-connected wireless gadgets. They say freeing it up would encourage innovation and investment in much the same way that the spread of Wi-Fi technology has. (This would, of course, generate more business for tech companies.)

But a coalition of old-guard media — from television networks to Broadway producers — is objecting to the proposal, saying it needs a closer look. The opponents argue that signals sent over those frequencies could interfere with broadcasts and wireless microphones at live productions.

The measure appears likely to pass, though its opponents have mounted a spirited late-stage lobbying effort supported by Senator Hillary Rodham Clinton, Democrat of New York, and others in Congress, the professional sports leagues, Las Vegas casinos, a coalition of rock musicians and, of late, Ms. Parton, who is soon to open a Broadway show called “9 to 5: The Musical.”

If the spectrum is set free, Ms. Parton says, chaos could reign on Broadway — in the form of static and other interference.

“The potential direct negative impact on countless people may be immeasurable,” Ms. Parton wrote in a letter last month to the F.C.C., urging it not to release the frequencies.

Ms. Parton got involved after she was contacted by the Broadway League, a theater-industry trade group that has lobbied the F.C.C. on the issue and coordinated support from performers. The trade group said Ms. Parton had been more engaged than other performers because she also was a producer of live shows.

In the digital era, airwaves carrying television, cellphone and wireless Internet signals are highly valuable. The F.C.C. regulates the spectrum and auctions off licenses for its use — in some cases for billions of dollars — to private companies. But in this case it is considering setting aside a free or “unlicensed” chunk for public use.

Tech companies argue that if it does so, entrepreneurs and innovators will create a new generation of devices that transmit signals farther and more reliably than Wi-Fi, which also relies on unlicensed spectrum. The technology could also handle cheap Internet-based phone calls.

“This could lead to Wi-Fi on steroids,” said Richard Whitt, a Washington lobbyist for Google on telecommunications issues. “It could become a ubiquitous nationwide broadband network.” The battle between the old- and new-media companies is a byproduct of an impending change in the way over-the-air TV signals are delivered. In February, TV stations will be required to switch over from analog broadcasting to digital, which is less susceptible to radio interference.

Since 2004, the F.C.C. has been studying whether it might make better use of some “white spaces,” TV frequencies that are not being used by broadcast channels. These frequencies have traditionally been left largely empty, because broadcasters send out such powerful signals that a buffer is needed between channels.

The theory behind the F.C.C. proposal is that handheld devices and other gadgets emit such low levels of power that their transmissions will not overlap or interfere with the digital TV signals. Plus, the proposal’s supporters say, devices can be made smart enough to sense when they might interfere with a broadcast signal and find another frequency.

The F.C.C. has been studying the potential for interference and found that most problems can be avoided through tight regulation of the new devices, said Kevin J. Martin, chairman of the F.C.C., who proposed the white space measure, and Michael J. Copps, a commissioner who supports it.

“Some want 100 percent certainty, and that’s kind of difficult to provide,” Mr. Copps said. But he added that he supported the measure because there was ample evidence that the new devices would not interfere, and that further study would amount to unnecessary delay.

“This unlicensed spectrum is going to be a tremendous force for innovation,” he said.

The five-member commission seems likely to approve the measure, according to several people involved in the agency’s internal discussions but who declined to be named because they were not authorized to speak to the media.

Beneath the surface of the debate are shifts in politics and culture. Heavy Internet and computer adoption by consumers has given the technology industry lobby more power and prominence. At the same time, the broadcast industry has lost some of its lobbying sway as consumer tastes have changed and advertising dollars have flowed to the Internet.

Still, the National Association of Broadcasters, which represents 8,300 local and national television stations, is helping lead the effort to get the F.C.C. to postpone a decision on the measure.

Without more testing, “this could be a recipe for potentially massive interference into the television spectrum,” said Dennis Wharton, a spokesman for the broadcasting trade group, arguing that TV screens could go temporarily dark or that pictures could freeze. Broadcasters say the signal could even disrupt channels received over cable.

The interest of TV providers is different from that of Broadway theaters, which rely on wireless microphones to broadcast sound to the audience and for communication among crew members.

Gerald Schoenfeld, chairman of the Shubert Organization, a Broadway production company, said new gadgets that were designed to use the disputed frequencies could interfere with the 450 wireless microphones used in New York’s theater district. That could lead to static, he said, or worse — if, for instance, crew member communications were interfered with, causing an accident, like a falling set piece.

“There’s a danger element attached to this,” he said. “They are fooling with many aspects of American society under the pretext of helping get Internet access for parties that already have the greatest amount of Internet usage.”

Urging a delay on the vote, Mr. Schoenfeld added: “Why this is being rushed through at this time is mystifying.”

The wireless microphone technology used for Broadway shows and other events uses some of the same frequencies that regulators would like to open up for wireless data. But under the F.C.C. proposal, these incumbent users would be given first rights to the space.

In her letter to the F.C.C., Ms. Parton conceded that she did not understand all the technicalities of the debate. But based on the counsel of others, she concluded that the potential problems were serious. She called the proposal “a dangerous and shortsighted answer to a highly complicated question.” The Broadway League and Ms. Parton’s representatives said she was too busy to comment further.

For his part, Eric E. Schmidt, the chief executive of Google, sent his own letter to the F.C.C. recently.

“We are eight days away from a vote that could transform the way we connect to the Internet,” he wrote. “The time for study and talk is over. The time for action has arrived.”

TOP TEN REASONS YOU SHOULD COME WITH US TO THE CHRISTIAN MUSICIAN SUMMIT '08!



10. It's a great excuse to skip work/school. (j.k.- sorta...;)
9. All the cool kids are doing it.
8. Starbucks in the morning on our way! Mmmmmm. Coofffffffffeeeeeeeee....
7. You get a lanyard with your name on it...AND you get to KEEP it!
6. You have always wanted to know what the inside of the church van looks like.
5. Lunch in a box never looked so good??
4. Did I mention we are stopping for coffee??
3. "Because I said so..." - (reason submitted by your mom) (O.K. Seriously..)
2. We get a great opportunity to hang together/learn together/eat together/sing silly van songs...and encourage each other in our gifting and calling in Worship!
1. Investing time in relationships with our Brothers and Sisters in Christ as well as the God given talents and calling on our lives and our Church Home is never ever a waste of time. Jesus comes with us. Wink

CMS

Details:

When: November 14th & 15th (Friday and Saturday)

Where: Overlake Christian Church - Renton, WA

How Much: $134.00 per person (not including food/coffee/instructional materials you may want to buy)



Google's Larry Page Calls FCC White Space Test 'Rigged'

By Thomas Claburn


In an address to Washington lawmakers on Wednesday to advocate opening of a portion of the television spectrum for Internet networking, Google co-founder Larry Page charged that a recent FCC "white space" device test had been rigged to fail.

Page, according to The Washington Post account of his remarks, said, "The test was rigged deliberately. That's the kind of thing we've been up against here, and I find it despicable."

The test Page referred to was conducted in August by the FCC's Office of Engineering and Technology. Its purpose was to determine whether a prototype device for transmitting Internet traffic over the unused white space in the TV spectrum could sense the presence of wireless microphone signals.

Google along with Dell, HP, Microsoft, Motorola, and others have been lobbying the FCC to authorize this use of the TV spectrum. They believe it could be used to connect underserved communities to the Internet at a low cost, to open the door for innovative new services, and to promote the development of an underused resource.

TV broadcasters, telecom companies, and wireless microphone companies are among those that oppose the idea, fearing disruption of their use of the spectrum, not to mention competition from a new form of Internet service.

On Aug. 19, following the FCC test, the White Spaces Coalition sent a letter to the FCC that echoed Page's claims. The letter charged that during the FedEx Field test, wireless microphone operators were broadcasting wireless microphone signals on multiple channels used by TV broadcasts.

Beyond being a violation of FCC rules, this buried the wireless microphone signals inside more powerful TV signals and assured that the Philips white space device being tested failed to detect wireless microphone signals.

Mark Brunner, senior director of public and industry relations at Shure, which makes wireless microphones, refuted Page's charges in an e-mailed statement.

"The FCC's wireless microphone field tests were carefully planned and thoroughly executed based on sound engineering science and real-world operating scenarios," he said. "These tests were open to the public, and those who choose to discount the results -- which have not yet been published -- had every option to be present and to witness them for themselves."

Call to Action: White Spaces

On November 4th, the FCC plans to change the rules that govern the use of wireless microphones and other wireless audio equipment. The new rules may make it impossible for you to continue using wireless microphones as you do today, and your entire inventory of wireless equipment may become obsolete within months.

The current deadline to send comments to the FCC on this issue is Monday, October 27th. It is critical that you act immediately to tell the FCC and your legislators that these changes are unacceptable to you.

Background

The FCC is reorganizing the UHF television band, coinciding with the transition from analog to digital television broadcasting. Soon, TV stations will occupy a smaller section of the UHF spectrum because digital stations can be spaced more closely together - even on adjacent channels - without interfering with each other. There will still be unoccupied channels in every market – referred to as “White Spaces” – just as there are now.

Why does this matter to you? These "White Spaces" are used by wireless microphones and instrument systems, in-ear monitors, and production intercom systems. Beginning on February 18, 2009, the FCC plans to allow consumer wireless devices – mobile phones, BlackBerry™’s, etc. – to access the internet using the same frequencies currently used by wireless audio equipment.

These devices can cause catastrophic interference if operated on the same frequency as wireless audio devices. The effect on a wireless microphone could be decreased range (perhaps to as little as 10 feet), an increase in the number and severity of audio dropouts, or even complete interruption of the signal. Tests have also proven that White Space devices can interfere with DTV reception and even cable TV signals.

Two Channels Are Not Enough

Shure has proposed that the FCC set aside eight ‘protected’ TV channels (2 in the VHF band and 6 in the UHF band) in each market, in which unlicensed wireless microphones could operate without interference from White Space devices. The devices would check an online database and avoid transmitting on the channels that are ‘protected’. The problem: the FCC plans to set aside only TWO TV channels for unlicensed wireless mics – and they won’t reveal where they are in the spectrum. Two TV channels (12 MHz of spectrum) would only be enough for four to ten wireless microphones – less if other wireless mic users are nearby. This is insufficient for many users.

Tests Say “No”, But The FCC Says “Go”

For wireless microphones operating outside of the two ‘protected’ channels, the FCC proposes to use a technology known as “spectrum sensing.” This would require White Space devices to detect DTV stations and wireless audio equipment and avoid transmitting on the frequencies that they are using. The FCC’s own tests have demonstrated that this technology often fails to detect that a wireless microphone is present, even at very short distances. The problem: the FCC plans to allow new devices that rely on spectrum sensing anyway.

No Clear Plan For Large-Scale Users

In situations where many wireless audio devices are in use, several open TV channels may be required. The FCC has proposed that users would need to register in an online database that would include the event location and duration. The problem: the FCC has not revealed who would have access to this database. Many types of wireless users could be locked out.


The FCC Needs to Hear From You

The FCC needs to hear from wireless users, installers, and resellers that sufficient protection for wireless microphones is essential. Contact the FCC and your Congressional representatives directly, using one of the links below. Tell them how important wireless audio equipment is to your organization’s activities. If you are a performer or producer, tell them how it will affect your performance or content. If you are an installer or reseller, tell them how this will impact your business.

NARAS

The National Academy of Recording Arts and Sciences

Click here to go to the NARAS Advocacy page, which allows you to find your U.S. Representatives and Senators by entering your zip code.

NAMM

The National Association of

Music Merchants

Click here to send a letter to the FCC specifically stating the interests of the music equipment industry.

INFOCOMM

The Audiovisual (AV) Association

To express your support for Infocomm’s letter to the FCC representing the interests of AV equipment dealers and installers, go to www.infocomm.org

Shure Incorporated

Click here for instructions on how to file a comment with the FCC, and a direct link to the FCC’s Electronic Comment Filing System.

Spectrum Reallocation & White Space An Explanation and Current Developments

October 21, 2008

Many questions have surfaced in recent weeks over the actions of the Federal Communications Commission (FCC) regarding digital television, spectrum re-allocation, and wireless microphone technology. These actions have an impact on the current professional wireless microphones. The following information is published in order to reduce misunderstanding about these issues.

How is the TV spectrum being reallocated? The U.S. is in transition from conventional analog TV to digital TV. This is scheduled to be completed on February 17, 2009. At this same time, the reassignment of TV channels 52-69 (698 – 806 MHz) will be completed. This band will partially be used for emergency communications in channels 63, 64, 68, and 69. The rights to use the majority of the remaining channels were auctioned to AT&T, Verizon, and Qualcomm to provide what is being termed as advanced wireless services (AWS). This raised billions of dollars for the federal government and was therefore called the digital dividend. This will affect wireless microphones operating between 698-806 MHz (generically called the 700 MHz band), such as our evolution wireless C range systems.

Is this the White Space issue I’ve been hearing about? No. The White Space debate is separate and distinct from the digital dividend.

Will my C range evolution wireless system operate after February 2009? Technically systems will still work. However, wireless mics will be prohibited to operate between 698 –806 MHz in the near future. This restriction could go into effect as early as February 17, 2009. It is likely the FCC will make an announcement after their meeting scheduled on November 4th, 2008.

What is the White Space debate? The FCC is considering to allow a new class of unlicensed consumer electronic products, known as white space devices (WSD), to operate in locally unused UHF TV channels 21-51. If enacted, these new devices would also affect wireless mic users.

The debate centers on how current licensed devices (wireless mics are considered to be licensed devices by the FCC) will be protected from these new unlicensed white space devices (WSD). The FCC has acknowledged the need to prevent interference from white space devices to digital television signals and wireless microphones. The FCC recently conducted tests on WSD prototypes and published a report in mid October. A link to this report is referenced below. Once again, we expect further FCC action after their meeting on November 4th.

What has Sennheiser been doing regarding the White Space debate? Sennheiser has been directly communicating with the FCC and legislators making them aware that the term “white space” is a misnomer since broadcasters, film producers, and professional entertainers have been using licensed devices, such as wireless microphones and monitoring systems, in this spectrum for years. Therefore major news, political, sports and entertainment events would not be able to operate reliably if the spectrum was randomly flooded by new unlicensed devices. To demonstrate this point, Sennheiser participated in the FCC field tests of WSD prototypes.

Sennheiser has also been deeply involved in helping to shape response to the FCC through the Professional Audio Manufacturers Association, the Sports Video Group, and the Microphone Interests Coalition.

What about the future? It is certain that the amount of spectrum available for wireless microphone use is shrinking. The 700MHz range will no longer be available for use for wireless mics. The remaining usable UHF spectrum may become smaller, or it may be shared with new devices. No matter what happens, Sennheiser will continue to support wireless microphone use with the most flexible products and service available.

Sennheiser is continually developing unique ways to face new challenges with the same reliability that has always characterized our products.

Explanation of Recent FCC Activity There have been two recent communications from the FCC that have caused heightened anxiety: Notice of Proposed Rule Making banning wireless mics from the 700 MHz band This NPRM can be read in its entirety at:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-08-188A1.pdf
http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-284758A1.pdf

Sennheiser had predicted this action. That's why we advised our customers back in early 2007 that the FCC was likely to impose restrictions on operating wireless mics between 698 MHz and 806 MHz. We therefore eliminated systems operating in this range from our regular assortment and made them available only based on a special order.

Sennheiser submitted a detailed response to this proposal on Oct 3rd and again on Monday, Oct. 20th.

We are lobbying hard for a measured migration out of the 700 MHz band that includes a grace period that would allow existing users to continue to operate in this band on a non-interference basis. The full comment to the FCC is posted on the following webpage: www.sennheiserusa.com/spectrumreallocation The White Space Technical Report The FCC executive summary can be found at: http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-08-2243A2.pdf

This report relates to spectrum sensing capabilities of proposed white space devices (WSD). Other than the FCC stating that "...we believe... the ‘proof of concept’ has been met," there is nothing new in this report.

1) WSD devices would still be required to detect and avoid wireless mics
2) Fixed WSD are being considered ahead of the more problematic portable units
3) More development is required on WSDs to meet the performance standards that have been set Furthermore, there is also a proposal being considered that would dedicate at least two TV channels in every market for wireless microphone use. Major events, such as sports, would have additional channels reserved.

The bottom line is this: wireless mics will continue to be used throughout our nation. The FCC has scheduled a discussion and may vote on these issues on November 4th. We will distribute the results of this vote as well as a detailed analysis of what this means to wireless mic users. In the meantime, feel free to contact me with further questions. Thank you.

Joe Ciaudelli
860-434-9190 Ext. 508
SENNHEISER ELECTRONIC CORP

Equalizing Lapel Mics

By Marty McCann

Question from: Ian Stott of Architectural Audio Singapore

"What EQ Settings/curve would you recommend for a lavaliere mic in a difficult environment such as a reverberant church or hall!"

I would recommend a Cardioid pattern lapel mic, even though the pattern is altered when placed on the chest. Some put the mic too far down on their chest. The user should drop their chin to their chest and put the mic directly below that point. The farther down from this point results in even more mid-range chest cavity resonance that colors the sound. This chest cavity resonance and the gain before feedback is a constant battle with lapels (Wireless or hard-wired).

Too often the church customer (who is often rather technically challenged in the first place), tries to resolve the EQ'ing of the lapel mic with the overall main system EQ. This of course is a mistake, because of how it will adversely affect the overall systems performance, i.e., normal vocal microphones and instruments taken direct are negatively affected by the hacking away of the main equalizer in order to chase away frequencies that are problems for the wireless Lav mic only. A dedicated EQ (inserted into the wireless Mic's channel) is the only way to begin to even get any kind of a handle on this application. Even then due to the drastic amount of Mid-range cut necessary to get intelligibility out of the lapel Mic system (this is before feedback suppression), there is often not enough cut remaining in this region for further control of feedback.

Over the years, I have addressed this problem in high visibility, high $'s installations by either using a parametric along with a 1/3 octave to tweak the system, or more recently (since we no longer manufacturer a parametric), I specify ½ of a 2/3 Octave EQ and a 1/3 Octave EQ to process the lapel Mic's channel.

Now here is where the problem is further complicated. In many installations, the lapel Mic is used by more than one individual (sometimes several). Due to the individual nature or timbre of peoples speaking voices, along with the fundamental resonance's of each voice (that is determined both by the vocal chords and the size of the chest cavity), one size does NOT, fit all. The pastor or CEO doesn't understand this at all. At times when it can be determined that certain designated people will be using the lapel system, I have specified 2 (yes 2) CEQ-280a programmable Equalizers, with stored setting for various presenters or speakers.

Now down to the EQ process. Too often the less experienced system integrator or operator will just ring out the mic for feed back. This results in less than desirable tone and intelligibility. EQ for intelligibility first then go for feedback suppression (once again you probably need more than 1 EQ to accomplish both effectively). On the average the required mid-range notch is centered somewhere from 315 to 630 Hz (this is the individual variable) depending on the person speaking. This notch can be two to three octaves wide at the -3dB down points (depending on the lapel mic and user). Because of the small Electret diaphragm and its proximity to the users mouth, there is often more energy above say 8 kHz than is necessary. A variable high cut is a good tool here (that's why I prefer the EQ-31FX over the Q-31FX, the variable low cut is also handy here). Some people's voices exhibit a strong sibilance in the annunciation of Ssss sounds. This of course is mainly at 6.3 kHz on a 1/3 Octave EQ.

When the budget won't allow for two equalizers, one technique is to first start with all of the EQ sliders at the top (this is not a good idea with some cheaper filter designs due to the ripple or poor summing of the filters), then to EQ for tone, followed by appropriate cuts for feedback suppression. With some cheap EQ's this technique would also result in a poor S/N ratio.

While on this subject, we have had tremendous results with the performance of our new PVM-2 wireless headset mic. Because of it's positioning away from the chest and close to the mouth, it needs VERY LITTLE EQ, and can often suffice on the channel strip EQ on a decent mixer. The problem is a lot of people think they look like a Dork with the headset on. In my case, I have overcome the dorky feeling because the end result is soooo much better performance.

Also, some theater productions tape the lapel Mic over the actor's ear or into their hairline (using flesh colored surgical tape). This works well with some of today's smaller Mic elements, such as the PVM-1 Lavaliere microphone.

©2009 Peavey Electronics. Used by permission All rights reserved. Terms/Privacy
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David McLain | The Wireless Guy! | CCI SOLUTIONS
Be seen. Be heard.
PO Box 481 / 1247 85th Ave SE
Olympia, WA 98507-0481
Voice: 800/426-8664 x255 / Fax: 800/399-8273

email: dmclain@ccisolutions.com
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