SBD4000

Powerful stereo sound stage

Powerful XSL Acoustics
The slim mono-body of the SBD4000 portable speaker system slips easily into your pocket or bag. Share the powerful and realistic stereo sound stage with friends wherever you are, and experience amazing rich bass quality even at low volume.

Sound
Frequency response : 100 - 20 000 Hz
Sound enhancement : Dynamic Bass Boost, Incredible surround
Impedance : 3 Ohm
RMS power rating : 2x3W (6W)
Sensitivity : >80 dB
Speaker diameter : 40 mm
Type : Neodymium

Connectivity
Cable length : 0.3 m
Connector : 3.5 mm stereo
Finishing of connector : Nickel plated

Convenience
Bass level control : Yes
Power on indication : Yes
Volume control : yes
Operating time : 6 hours

Accessories
AC/DC adaptor : Yes
Pouch : Yes

Power
Adaptor type : 9V 500mA
Battery type : AAA, LR03
Battery voltage : 1.5 V
Number of batteries : 6

Inner Carton
12NC : 8670 000 26919
EAN/UPC/GTIN : 87 12581 31536 8
Gross weight : 1.580 kg
Height : 206 mm
Length : 224 mm
Quantity : 2
Tare weight : 0.138 kg
Width : 178 mm

Outer Carton
12NC : 867000026919
EAN/UPC/GTIN : 87 12581 31539 9
Gross weight : 5.642 kg
Height : 229 mm
Length : 549 mm
Quantity : 6
Tare weight : 0.902 kg
Width : 235 mm

Packaging Data
12NC : 867000026919
EAN/UPC/GTIN : 87 12581 31533 7
Gross weight : 0.721 kg
Height : 188 mm
Length : 217 mm
Tare weight : 0.162 kg
Width : 85 mm

XLR audio connectors.

The XLR connector is an electrical connector design. XLR plugs and sockets are used mostly in professional audio and video electronics cabling applications. Home audio and video electronics normally use RCA connectors.

In reference to its original manufacturer, Cannon (now part of ITT), the connector is colloquially known as a cannon plug or canon. Originally the "Cannon X" series, subsequent versions added a Latch ("Cannon XL") and then a Rubber compound surrounding the contacts, which led to the abbreviation XLR.Many companies now make XLRs. The initials "XLR" have nothing to do with the pinout of the connector. XLR connectors can have other numbers of pins besides three.They are superficially similar to the older smaller and less rugged DIN connector range, but are not physically compatible with them.

The most common is the 3-pin XLR3, used almost universally as a balanced audio connector for high quality microphones and connections between equipment. XLR4s with four pins are used for ClearCom, Tecpro intercom systems, 12 volt power, and the older AMX analog lighting control. The XLR5 is the standard connector for DMX512 digital lighting control.

Many other types exist, with various pin numbers. Most notable are two now obsolete 3-pin patterns manufactured by ITT Cannon. The power Cannon (also called the XLR-LNE connector) had shrouded pins and red insulation, it was intended as a mains power connector, but has been superseded by the IEC mains connector and increasingly, more recently, the PowerCon connector developed by Neutrik.

The loudspeaker Cannon had blue or white insulation (depending on its gender), was intended for connections between audio power amplifiers and loudspeakers. At one time XLR3 connectors were also used extensively on loudspeaker cables, as when first introduced they represented a new standard of ruggedness, and economic alternatives were not readily available. The convention was that a 2-conductor loudspeaker cable had XLR3F connectors on both ends, to distinguish it from a 3-conductor shielded signal level cable which has an XLR3F at one end and an XLR3M at the other. Either pin 2 or 3 was live, depending on the manufacturer, with pin 1 always the 'earthy' return. This usage is now both obsolete and dangerous to equipment but is still sometimes encountered, especially on older equipment. For example, some loudspeakers have a built-in XLR3M as an input connector. This use was superseded in professional audio applications by the Neutrik Speakon connector.

The female XLR connectors are designed to first connect pin 1 (the earth pin), before the other pins make contact, when a male XLR connector is inserted. With the ground connection established before the signal lines are connected, the insertion (and removal) of XLR connectors in live equipment is possible without picking up external signals (as it usually happens with, for example, RCA connectors).

When looking at the socket, the top left hole is 2, top right is 1, and bottom is 3. When looking at the plug, the top left pin is 1, top right is 2, and bottom is 3.

Some audio equipment manufacturers reverse the use of pin 2 (properly the normal input) and pin 3 (inverting input). This reflects their own previous usage before any standard existed. Pin 1 is always ground, and many connectors connect it internally to the connector shell or case.

Note that neither the standards nor manufacturers agree on the best way to handle the usage of pin 1 at both ends of a cable, particularly with respect to the cable shield, the connector's shell, signal ground, and a third cable wire connected to pin 1 -- which may (or may not) be connected to the shield. Comments on AES48

An XLR3M (male) connector is used for an output and an XLR3F (female) for an input. Thus a microphone will have a built-in XLR3M connector, and signal cables such as microphone cables will each have an XLR3F at one end and an XLR3M at the other. At the stage box end of a multicore cable, the inputs to the mixing desk will be XLR3F connectors, while the returns to the stage will be XLR3M connectors. Similarly, on a mixing desk, the microphone inputs will be XLR3F connectors, and any balanced outputs XLR3M connectors.

An old audio engineer once told me the easiest way to remember pin wiring and functions on an XLR connector is to write 1, 2 and 3 down the side of a piece of paper. Then next to 1 write X, next to 2 write L and next to 3 write R. Finally on the top line write Ground, next line write Line (or Live or phase if you prefer), and bottom line - Return.

Like this..

1 X Ground

2 L Line

3 R Return

This type of instruction has been given to engineering professionals at Univision, USA Broadcasting, Telefutura, Florida International University, and Comcast (for local origination projects).

JVC HA-NCX77 Noise Canceling Earbuds

For many in-ear headphone users, the passive noise isolation offered by an effective seal with the ear is plenty. In fact, some even find the essentially inaudible filler of active noise cancellation irritating to the ear. But if you're a frequent flier who needs more noticeable hushing of low-frequency rumblings and who wants it to come in a super-compact package, all is not lost. The JVC HA-NCX77 earbuds offer battery-powered noise cancellation for a very palatable $79.95.

As far as earbuds go, the JVC HA-NCX77s aren't all that compact. That's simply because in order to incorporate active noise cancellation, JVC had to attach a box to the cable that could take a battery and let you turn the feature on and off. Unfortunately, there's no way to detach the unit from the headphone cable so, although you can listen to tunes sans battery (with noise cancellation off, of course), you cannot get rid of the box while doing so. The box itself is roughly the size of a flash MP3 player (the Nano, for example), and it incorporates a battery compartment and handy belt clip on the back, a power switch and volume knob on the side, and a monitor switch on the front. The latter is a rather useful feature that lets you mute playback so you can hear your surroundings without taking the earbuds out (note that this does not pause your song).

As for the earbuds themselves, they're admirably tiny with a shiny gunmetal finish. JVC includes three sets of silicone ear tips in different sizes and--shock of all shocks--the smallest ones fit in my freakishly tiny ears perfectly. Provided you can get an adequate seal with the ear, the HA-NCX77s offer good passive noise isolation, so you can save the battery (one AAA, included) for situations with excessive low frequency noise (trains, planes, and subways). The cable running from the earbuds to the noise cancellation box is 36 inches, so it should be long enough for even tall individuals to keep the box comfortably clipped to a waistband. A 30-inch stereo patch cable, which is included in the package, runs from the box to the sound source and is sufficiently long for storing your MP3 player out of sight in a bag or purse.

With so few things to complain about so far, I half-expected the HA-NCX77s to offer disappointing results during sound-quality testing. Fortunately, my jaded expectations were not met: these earbuds sound great. Most surprising is the excellent bass response, which rivals many full-size headphones in the same price range. And while the low end will satisfy bass addicts, it's not overpowering: all in all, music sounds rich and warm with sparkly highs and a balanced midrange. I sampled rock, hip hop, jazz, and electronica, and the headphones performed well across each genre. The noise cancellation feature works fine, though as the 'buds offer good passive isolation anyway, it's not terribly noticeable. The 70-hour battery life is certainly adequate.

Reviewed by: Jasmine France

Microphones overview

Sound is an amazing thing. All of the different sounds that we hear are caused by minute pressure differences in the air around us. What's amazing about it is that the air transmits those pressure changes so well, and so accurately, over relatively long distances.

If you have read the HowStuffWorks article How CDs Work, you learned about the very first microphone. It was a metal diaphragm attached to a needle, and this needle scratched a pattern onto a piece of metal foil. The pressure differences in the air that occurred when you spoke toward the diaphragm moved the diaphragm, which moved the needle, which was recorded on the foil. When you later ran the needle back over the foil, the vibrations scratched on the foil would then move the diaphragm and recreate the sound. The fact that this purely mechanical system works shows how much energy the vibrations in the air can have!

All modern microphones are trying to accomplish the same thing as the original, but do it electronically rather than mechanically. A microphone wants to take varying pressure waves in the air and convert them into varying electrical signals. There are five different technologies commonly used to accomplish this conversion:
Carbon microphones - The oldest and simplest microphone uses carbon dust. This is the technology used in the first telephones and is still used in some telephones today. The carbon dust has a thin metal or plastic diaphragm on one side. As sound waves hit the diaphragm, they compress the carbon dust, which changes its resistance. By running a current through the carbon, the changing resistance changes the amount of current that flows. See How Telephones Work for more information.

Dynamic microphones - A dynamic microphone takes advantage of electromagnet effects. When a magnet moves past a wire (or coil of wire), the magnet induces current to flow in the wire. In a dynamic microphone, the diaphragm moves either a magnet or a coil when sound waves hit the diaphragm, and the movement creates a small current.

Ribbon microphones - In a ribbon microphone, a thin ribbon is suspended in a magnetic field. Sound waves move the ribbon which changes the current flowing through it.

Condenser microphones - A condenser microphone is essentially a capacitor, with one plate of the capacitor moving in response to sound waves. The movement changes the capacitance of the capacitor, and these changes are amplified to create a measurable signal. Condenser microphones usually need a small battery to provide a voltage across the capacitor.

Crystal microphones - Certain crystals change their electrical properties as they change shape (see How Quartz Watches Work for one example of this phenomenon). By attaching a diaphragm to a crystal, the crystal will create a signal when sound waves hit the diaphragm.
As you can see, just about every technology imaginable has been harnessed to convert sound waves into electrical signals. The one thing they all have in common is the diaphragm, which collects the sound waves and creates movement in whatever technology is being used to create the signal.