вторник, 17 сентября 2013 г.

Virtual Surround Sound Systems - Big Sound Without Big Speakers

The newest must-have for anyone with a TV and stereo these days is a home theater setup. As usual for our got-to-have-the-best society, most people think big when they dream of their ideal home theater. How big? You know, big screen television, big sound from a powerful receiver and amplifier, and really big sound from the speakers spread all over the room.
But, once the dream dissolves into reality, many of us realize that this big setup just will not work in our homes. We might not have the room for all those speakers. After all, 5 speakers and a sub-woofer do take up a considerable amount of space. Or maybe, we just do not want all those cables running around the base boards. Or, we do not want the technical hassles of setting up and balancing such a large system.
Fortunately, those with limited space or minimalist design ideas still have options. The appeal of surround sound can be addressed in a different way. Technology has stepped in and developed what is being called virtual surround sound. Virtual surround sound has been developed to mimic the sound characteristics of a multi-speaker system. Even though it uses fewer speakers and cables, a virtual system approaches the overall sound of a 5.1 or 7.1 amplifier and speaker system. There are two primary varieties of virtual systems, the 2.1 surround system and the digital sound projection system.
The standard placement for the 2.1 speaker system is to place two speakers in front of the listener, along with a sub-woofer placed somewhere inconspicuously in the room. The system will recreate the effect of a larger 5.1 setup that has 5 speakers and the sub. On the other hand, digital sound projectors will use a single strip of relatively small speakers to produce the sound. Most often, the digital sound system will not have a sub-woofer.
In either case, even though the setup is different, the same basic principle exists. The technology behind the system is based on a knowledge of how humans process sound internally. There are certain techniques used to modify the sound waves to fool the human ear into thinking that there are more speakers than what really are present. These techniques come from studies of psycho-acoustics, or the study of the way that people perceive sound. To fully appreciate what technology has done, you need to understand a least a little about psycho-acoustics, as well as physical acoustics (the science of sound).
Charles Moore is a technical adviser for Audio Equipment Speakers questions and specializes in addressing unique sound reproduction problems. He has an extensive background in live sound applications for various size venues, as well as the recording studio. He believes that the best performance in the world can be ruined with just a second or two of bad sound reinforcement. The proof of a well-designed sound equipment speaker application is that it is not even noticed by the audience. Invisibility is the ultimate goal.

Some Insights Into Wireless Speakers

Looking at some of the technical specs of today's wireless speakers, one cannot help but be at a loss in trying to compare different models. I will give a short overview of the output power spec in order to help you better understand the meaning of this term and how they relate to the performance of an speaker.
Some of the terms which speaker manufacturers publish often are misleading and do not necessarily give a good indication of the actual performance of the speaker. Now I will give some details about "speaker wattage". This spec is often misunderstood. It is important to look fairly closely at how the manufacturer shows this parameter.
"Wattage" shows how loud your loudspeaker can sound. You want to pick the speaker wattage based on how large your listening environment is. For best audio quality, you may want to go with a speaker that has higher power than you need since many speakers will show increasing distortion as the audio power goes up.
There are two common ways to display loudspeaker wattage. These are "peak power" and "rms power". "Peak power" describes how much power the speaker can tolerate for a short burst. On the other hand, "rms power" describes how much power the speaker can tolerate for a prolonged amount of time without being damaged. The peak power rating in the past often led to manufacturers showing large wattage ratings for small speakers. However, in reality those speakers would not be able to endure larger amounts of output power for larger amounts of time.
Today most speakers will specify rms power which gives a better indication of the speakers' true performance. However, please ensure that your speaker has enough headroom to avoid clipping of the audio. This is because at certain points in time the signal will have bursts of power which by far exceed the average power of the signal.
Usually the impedance of the speakers which you connect to your amp will determine how much power your amp can deliver. Speaker impedance is measured in Ohms. Typically speakers have an impedance between 4 and 8 Ohms. An audio amplifier which has a fixed internal supply voltage will have a maximum output signal swing that is limited by that supply voltage. If you are driving an 8-Ohm speaker then your amplifier must deliver twice the output voltage than when driving a 4-Ohm speaker in order to deliver the same amount of power to your speaker. Usually maximum power is specified for a 4-Ohm speaker impedance. However, ideally the manufacturer of your amplifier will tell which speaker impedance the amplifier can drive. Please note that some amplifiers cannot drive speakers with very low speaker impedance.

среда, 1 мая 2013 г.

Choosing the Right Speaker

Speakers can add immeasurably to a meeting by motivating, entertaining, enlightening or teaching a skill. An inappropriate speaker, on the other hand, can lead to disastrous results. Here's a look at how to find the right speaker for your event and how to work with speakers to make sure their presentation - and your event - are a success.
The key question is: How does an organization choose? How can you be sure that you'll get a speaker who is right for your organization? Start by asking yourself these questions:
  • Why is this meeting being held?
  • What do we want the attendees to know, think, or feel after this meeting?
  • What issues or challenges are the attendees facing right now?
Your answers should help you narrow your search. And remember, much is at stake. A speaker can, and often will, set the tone for your meeting. Select poorly, and there's a strong chance your meeting will suffer. Attendees will long recall a speaker who bombed. There's a lot financially at stake, too; speakers do not come cheap, typically charging thousands of dollars for their services. Once again, the key is to know your organization, know your circumstances, and know your audience.
A speakers bureau can help you narrow your search down to that one speaker who is perfect for your organization. Here's how:
Knowing who's hot. A speakers bureau is on the phone with meeting planners all day long, reviewing speakers, hearing from planners about what wireless outdoor speakers they've used, who was good, who wasn't. Bureaus know the speaker's capabilities.
Wider Access. Speakers bureaus have access to thousands of professional speakers, industry experts, and celebrities. Occasionally, a big-name celebrity will have exclusive management with a particular bureau, but that does not mean other bureaus aren't able to book that celebrity. In such cases, the celebrity's bureau and the bureau representing the meeting planner "co-broker" the deal.
Negotiating Fees. In addition to selecting appropriate speaker within a group's budget, the speakers bureau will negotiate the speaker's fee on behalf of the client - that is, if the fee is open to negotiation. The meeting planner's organization does not pay extra for the services of a speakers bureau; the bureau receives a percentage of the speaker's fee, much as a travel agent is compensated for selling airline tickets.
Finding Replacements. One big advantage of using a waterproof wireless Bluetooth speaker bureau is that if a speaker cancels, even at the last minute, the bureau will line up a replacement that meets the client's needs.
The best way to assure that you're a quality speaker is to see the speaker in action - or at least the speaker's demo video and question meeting planners who have used the speaker. Do not rely solely on the demo video, since a five-minute snippet is not necessarily an indication of how well a speaker will perform. Another approach is to call at least three meeting executives familiar with the prospective speaker's work, and ask:
  • Did the speaker skillfully customize the presentation?
  • Did the speaker have a good presentation technique, i.e., use anecdotes, examples, humor?
  • Was the speaker easy to work with, or did he/she make unreasonable requests?
  • How did attendees rate the speaker?
  • Would you use the speaker again?
Find out if the speaker holds the speaking industry's major designations: CSP (Certified Speaking Professional) or the CPAE (Council of Peers Award for Excellence). The National Speakers Association confers both. The CSP signifies achievement through a proven record of speaking experience; the recipients have made a minimum number of paid presentations and earned a minimum number of continuing education credits. The CPAE is awarded to up to five NSA members annually for demonstrated platform experience and professionalism.
Basic Fees. Fees vary widely, ranging from $1,000 to $50,000 or more. Luminaries such as management guru Michael Porter, billionaire entrepreneur Richard Branson and former president Bill Clinton are on the high end. Speakers are paid in a variety of ways but generally require a deposit - 50 percent is typical - at the time of booking, with the balance due shortly before the engagement or on site.
Variations in the basic fee. Keep in mind that professional speakers - those who do this for a living - are likely to set their fees according to how long they'll be at your event. For instance, the speaker might have a keynote fee that covers a single keynote address of up to 90 minutes. If the speaker plans to do the keynote address, speak at a break-out session, and perhaps stay for the luncheon, he might charge a higher fee. Many professional speakers have half-day and full-day rates in addition to keynote fees.
Travel and other costs. For the privilege of having the speaker address your group, you pay the speaker's fee plus travel and accommodation costs (hotel and meals). A speaker's expenses typically start at $1,000 - or more if he or she is flying first-class.
Negotiating fees. Are speakers fees carved in stone? No, fees are often negotiable, even those of some of the top tier speakers. In fact, you shouldn't be too quick to accept the first price you're quoted. Don't be shy about negotiating.
Here are some ways to keep a lid on the cost of hiring speakers:
Who's local? Look for speakers who are based in the city where you'll be holding your event. Some speakers spend their entire lives on the road, and may welcome a gig close to home. A Boston-based speaker may be amenable to offering a deal on his rate in order to address your meeting in Boston. And, of course, you'll avoid travel and accommodation expenses.
Does he have something to sell? A speaker with a book or a video to sell may be willing to accept a lower fee if allowed to peddle their wares at your event.
Can you share costs with another group? Check with the hotel or local convention and visitors bureau about other events scheduled the same day. You could "share" the services of the speaker - and thus share the cost.
What else can a speaker do? Try to get more bang for your buck by having the speaker agree, lets say, to attend a break-out session in addition to giving a major talk. The speaker could be willing to do the break-out at little to know additional cost.
Offer video. If you plan to record the speaker's presentation, offer to produce extra copies of the video for the speaker's use. The speaker may be willing to cut you a deal on the fee.
Call your Congressman. Approach speakers who do not accept fees - current officeholders, for instance. If you'll be meeting, say, in and around Washington, D.C., a member of congress could speak on a legislative topic of interest to your group.
Primarily, the contract should clearly lay out your expectations and the speaker's. It should cover the following:
  • Travel and local transportation arrangements.
  • Accommodations and meals.
  • Fees and payment terms.
  • Customization of remarks.
  • Additional duties expected of the speaker, such as mingling with attendees or signing autographs.
  • Whether and how the speaker will sell products such and books and DVDs.
  • Agreements to record the speaker's presentation (in most cases, you'll need permission to record).
  • Audiovisual and technical requirements.
  • Cancellation policies.

You should thoroughly brief the speaker about your organization (i.e. goals, accomplishments, challenges), your organization's industry, and the size and demographics of the audience. This is particularly important if you are expecting the speaker to customize the presentation. Many celebrity speakers are not amenable to customizing their remarks, but it is almost a given among most professional speakers. At the very least, furnish the speaker with the most recent annual report, a published history of your organization, any pertinent news clippings, and the names of key people and specific industry buzzwords that you'll want the speaker to incorporate.
You may also want to have the speaker interview key members of your organization in the weeks before the event. But don't assume the speaker will do extensive preparation work for nothing. Sometimes, speakers will charge extra for customizing because of the research they have to do.

Article Source: