Martin Red
03-26-2003, 05:38 AM
Sound Basics
To understand how speakers work, you first need to understand how sound works.
Inside your ear is a very thin piece of skin called the eardrum. When your eardrum vibrates, your brain interprets the vibrations as sound -- that's how you hear. Rapid changes in air pressure are the most common thing to vibrate your eardrum.
An object produces sound when it vibrates in air (sound can also travel through liquids and solids, but air is the transmission medium when we listen to speakers). When something vibrates, it moves the air particles around it. Those air particles in turn move the air particles around them, carrying the pulse of the vibration through the air as a traveling disturbance.
To see how this works, let's look at a simple vibrating object -- a bell. When you ring a bell, the metal vibrates -- flexes in and out -- rapidly. When it flexes out on one side, it pushes out on the surrounding air particles on that side. These air particles then collide with the particles in front of them, which collide with the particles in front of them and so on. When the bell flexes away, it pulls in on these surrounding air particles, creating a drop in pressure that pulls in on more surrounding air particles, which creates another drop in pressure that pulls in particles that are even farther out and so on. This decreasing of pressure is called rarefaction.
SOURCE: http://howstuffworks.lycoszone.com/speaker1.htm
http://www.hi-fiworld.co.uk/hfw/hfwImages/oldeworlde/yamahans1000m.gif
"Why, if humankind has put vehicles on Mars and mastered open-heart surgery, can it not design an accurate loudspeaker? Even at the best of times, modern 'speakers are compromised devices, and getting one to work properly from 20Hz to 20kHz is still an uncommon occurrence.
Given that moving-coil drivers have all sorts of colorations to sully them, and that electrostatics only work effectively over a limited frequency range, engineers have to employ clever tricks to get the best from these units. Back in the early Seventies, Yamaha decided the answer was Beryllium domes, and the NS1000 was born.
Using this expensive metal, Yamaha came up with treble and midrange drivers that produced extremely low levels of distortion, excellent dispersion and phase coherence. In fact, mated together by a complex crossover network, they behaved much as an electrostatic panel but with more extended highs and better power handling. Matched with a fast, light, rigid paper-coned 300mm bass unit, the combination was dynamite.
The first NS1000s went on sale in 1975, built like the proverbial brick powder room and with HF and midrange trim pots built into the front baffles. At over £400, their price reflected their advanced engineering and superb 32kg-per-box build. They were quite unlike anything people had ever heard * best described as sounding like a Quad ESL with a ribbon super-tweeter and a sub-woofer to handle the lows!
In Japan and the States they were rapturously received, with recording studios and broadcast companies throwing their money at Yamaha. Quite simply, there was no other 'speaker to touch the NS1000's combination of transparency, speed and power handling. But over here, reactions were mixed. Reviewers used to soft, bland Bextrene-coned BBC monitors found them forward and fatiguing and prone to harshness and fizz.
The problem was that the Yamahas were utterly unforgiving of the amps that drove them. With high sensitivity and a relatively easy load, most Japanese audiophiles were using them with muscular valve amps that had a warm, smooth sound. In Britain the fashion was for big, punchy transistor power amps such as Naim's NAP250, which, without soft Bextrene or polypropylene cones to hide behind, could sound * yes, that's right * forward, fatiguing and fizzy!
In 1977 the NS1000s gained slightly smaller, more rigid cabinets, black paint and an 'M' suffix. Re-reviewed by the UK press, they were decried as harsh - with the exception of Practical Hi-Fi, whose reviewer used them with the then seriously unfashionable Quad II and gave them a big thumbs up. Funny, that.
In truth, the NS1000Ms are one of the most transparent 'speakers ever made, with dazzlingly fast transients, superb sound staging and great clarity and detail. But they also have a JBL-like capacity to inject life, drama and scale into everything they touch * a formidable combination of virtues!
Partner them with valves or Class A tranny power amps, turn the midrange trim pot down to *3dB (they do have a slight mid-forward balance, but this assuages it), site them on sturdy, low stands (Atacama BD200s are perfect) and you'll struggle to find a 'speaker that's as much fun.
Although Yamaha discontinued the NS1000M in the UK in 1995, in Japan it lives on as the NS1000X. With the M's fabled mid and treble units plus an improved carbon-fibre woofer, it's a fantastic loudspeaker. But top dog is the anniversary edition NS10000, big enough to make the '1000 look like a Wharfedale Diamond!"
http://www.locationsound.com/98summer/images/reveal.gif http://www.tannoy.com/images/revealx_m.jpg
Tannoy Professional has added three new models to its successful Reveal nearfield monitoring range, providing additional Reveal solutions for both stereo and 5.1 surround monitoring in music, broadcast, post-production, AV and mobile recording environments. Joining the successful Reveal and Reveal Active monitors are the Reveal X (shown here) and two active sub-bass speakers, the Reveal Sub 10 and the Sub 15 5.1. The Sub 15 5.1 incorporates all 6 amplifier channels for a complete 5.1 system.
________________________________________
Boxes of Sound
In most loudspeaker systems, the drivers and the crossover are housed in some sort of speaker enclosure. These enclosures serve a number of functions. On their most basic level, they make it much easier to set up the speakers. Everything's in one unit and the drivers are kept in the right position, so they work together to produce the best sound. Enclosures are usually built with heavy wood or another solid material that will effectively absorb the driver's vibration. If you simply placed a driver on a table, the table would vibrate so much it would drown out a lot of the speaker's sound. Additionally, the speaker enclosure affects how sound is produced. When we looked at speaker drivers, we focused on how the vibrating diaphragm emitted sound waves in front of the cone. But, since the diaphragm is moving back and forth, it's actually producing sound waves behind the cone as well. Different enclosure types have different ways of handling these "backward" waves.
The most common type of enclosure is the sealed enclosure, also called acoustic suspension enclosure. These enclosures are completely sealed, so no air can escape. This means the forward wave travels outward into the room, while the backward wave travels only into the box. Of course, since no air can escape, the internal air pressure is constantly changing -- when the driver moves in, the pressure is increased and when the driver moves out, it is decreased. Both movements create pressure differences between the air inside the box and the air outside the box. The air will always move to equalize pressure levels, so the driver is constantly being pushed toward its "resting" state -- the position at which internal and external air pressure are the same.
http://static.howstuffworks.com/gif/speaker-closed.gif
In a sealed speaker setup, the driver diaphragm compresses air in the enclosure when it moves in and rarefies air when it moves out.
These enclosures are less efficient than other designs because the amplifier has to boost the electrical signal to overcome the force of air pressure. The force serves a valuable function, however -- it acts like a spring to keep the driver in the right position. This makes for tighter, more precise sound production.
Other enclosure designs redirect the inward pressure outward, using it to supplement the forward sound wave. The most common way to do this is to build a small port into the speaker. In these bass reflex speakers, the backward motion of the diaphragm pushes sound waves out of the port, boosting the overall sound level. The main advantage of bass reflex enclosures is efficiency. The power moving the driver is used to emit two sound waves rather than one. The disadvantage is that there is no air pressure difference to spring the driver back into place, so the sound production is not as precise.
http://static.howstuffworks.com/gif/speaker-bass-reflex.gif
A bass reflex speaker produces two sound waves by moving one driver. When the driver compresses air forward, it rarefies it backward, and vice versa. The second sound wave is emitted from a port at the base of the speaker enclosure.
SOURCE http://howstuffworks.lycoszone.com/speaker4.htm
To understand how speakers work, you first need to understand how sound works.
Inside your ear is a very thin piece of skin called the eardrum. When your eardrum vibrates, your brain interprets the vibrations as sound -- that's how you hear. Rapid changes in air pressure are the most common thing to vibrate your eardrum.
An object produces sound when it vibrates in air (sound can also travel through liquids and solids, but air is the transmission medium when we listen to speakers). When something vibrates, it moves the air particles around it. Those air particles in turn move the air particles around them, carrying the pulse of the vibration through the air as a traveling disturbance.
To see how this works, let's look at a simple vibrating object -- a bell. When you ring a bell, the metal vibrates -- flexes in and out -- rapidly. When it flexes out on one side, it pushes out on the surrounding air particles on that side. These air particles then collide with the particles in front of them, which collide with the particles in front of them and so on. When the bell flexes away, it pulls in on these surrounding air particles, creating a drop in pressure that pulls in on more surrounding air particles, which creates another drop in pressure that pulls in particles that are even farther out and so on. This decreasing of pressure is called rarefaction.
SOURCE: http://howstuffworks.lycoszone.com/speaker1.htm
http://www.hi-fiworld.co.uk/hfw/hfwImages/oldeworlde/yamahans1000m.gif
"Why, if humankind has put vehicles on Mars and mastered open-heart surgery, can it not design an accurate loudspeaker? Even at the best of times, modern 'speakers are compromised devices, and getting one to work properly from 20Hz to 20kHz is still an uncommon occurrence.
Given that moving-coil drivers have all sorts of colorations to sully them, and that electrostatics only work effectively over a limited frequency range, engineers have to employ clever tricks to get the best from these units. Back in the early Seventies, Yamaha decided the answer was Beryllium domes, and the NS1000 was born.
Using this expensive metal, Yamaha came up with treble and midrange drivers that produced extremely low levels of distortion, excellent dispersion and phase coherence. In fact, mated together by a complex crossover network, they behaved much as an electrostatic panel but with more extended highs and better power handling. Matched with a fast, light, rigid paper-coned 300mm bass unit, the combination was dynamite.
The first NS1000s went on sale in 1975, built like the proverbial brick powder room and with HF and midrange trim pots built into the front baffles. At over £400, their price reflected their advanced engineering and superb 32kg-per-box build. They were quite unlike anything people had ever heard * best described as sounding like a Quad ESL with a ribbon super-tweeter and a sub-woofer to handle the lows!
In Japan and the States they were rapturously received, with recording studios and broadcast companies throwing their money at Yamaha. Quite simply, there was no other 'speaker to touch the NS1000's combination of transparency, speed and power handling. But over here, reactions were mixed. Reviewers used to soft, bland Bextrene-coned BBC monitors found them forward and fatiguing and prone to harshness and fizz.
The problem was that the Yamahas were utterly unforgiving of the amps that drove them. With high sensitivity and a relatively easy load, most Japanese audiophiles were using them with muscular valve amps that had a warm, smooth sound. In Britain the fashion was for big, punchy transistor power amps such as Naim's NAP250, which, without soft Bextrene or polypropylene cones to hide behind, could sound * yes, that's right * forward, fatiguing and fizzy!
In 1977 the NS1000s gained slightly smaller, more rigid cabinets, black paint and an 'M' suffix. Re-reviewed by the UK press, they were decried as harsh - with the exception of Practical Hi-Fi, whose reviewer used them with the then seriously unfashionable Quad II and gave them a big thumbs up. Funny, that.
In truth, the NS1000Ms are one of the most transparent 'speakers ever made, with dazzlingly fast transients, superb sound staging and great clarity and detail. But they also have a JBL-like capacity to inject life, drama and scale into everything they touch * a formidable combination of virtues!
Partner them with valves or Class A tranny power amps, turn the midrange trim pot down to *3dB (they do have a slight mid-forward balance, but this assuages it), site them on sturdy, low stands (Atacama BD200s are perfect) and you'll struggle to find a 'speaker that's as much fun.
Although Yamaha discontinued the NS1000M in the UK in 1995, in Japan it lives on as the NS1000X. With the M's fabled mid and treble units plus an improved carbon-fibre woofer, it's a fantastic loudspeaker. But top dog is the anniversary edition NS10000, big enough to make the '1000 look like a Wharfedale Diamond!"
http://www.locationsound.com/98summer/images/reveal.gif http://www.tannoy.com/images/revealx_m.jpg
Tannoy Professional has added three new models to its successful Reveal nearfield monitoring range, providing additional Reveal solutions for both stereo and 5.1 surround monitoring in music, broadcast, post-production, AV and mobile recording environments. Joining the successful Reveal and Reveal Active monitors are the Reveal X (shown here) and two active sub-bass speakers, the Reveal Sub 10 and the Sub 15 5.1. The Sub 15 5.1 incorporates all 6 amplifier channels for a complete 5.1 system.
________________________________________
Boxes of Sound
In most loudspeaker systems, the drivers and the crossover are housed in some sort of speaker enclosure. These enclosures serve a number of functions. On their most basic level, they make it much easier to set up the speakers. Everything's in one unit and the drivers are kept in the right position, so they work together to produce the best sound. Enclosures are usually built with heavy wood or another solid material that will effectively absorb the driver's vibration. If you simply placed a driver on a table, the table would vibrate so much it would drown out a lot of the speaker's sound. Additionally, the speaker enclosure affects how sound is produced. When we looked at speaker drivers, we focused on how the vibrating diaphragm emitted sound waves in front of the cone. But, since the diaphragm is moving back and forth, it's actually producing sound waves behind the cone as well. Different enclosure types have different ways of handling these "backward" waves.
The most common type of enclosure is the sealed enclosure, also called acoustic suspension enclosure. These enclosures are completely sealed, so no air can escape. This means the forward wave travels outward into the room, while the backward wave travels only into the box. Of course, since no air can escape, the internal air pressure is constantly changing -- when the driver moves in, the pressure is increased and when the driver moves out, it is decreased. Both movements create pressure differences between the air inside the box and the air outside the box. The air will always move to equalize pressure levels, so the driver is constantly being pushed toward its "resting" state -- the position at which internal and external air pressure are the same.
http://static.howstuffworks.com/gif/speaker-closed.gif
In a sealed speaker setup, the driver diaphragm compresses air in the enclosure when it moves in and rarefies air when it moves out.
These enclosures are less efficient than other designs because the amplifier has to boost the electrical signal to overcome the force of air pressure. The force serves a valuable function, however -- it acts like a spring to keep the driver in the right position. This makes for tighter, more precise sound production.
Other enclosure designs redirect the inward pressure outward, using it to supplement the forward sound wave. The most common way to do this is to build a small port into the speaker. In these bass reflex speakers, the backward motion of the diaphragm pushes sound waves out of the port, boosting the overall sound level. The main advantage of bass reflex enclosures is efficiency. The power moving the driver is used to emit two sound waves rather than one. The disadvantage is that there is no air pressure difference to spring the driver back into place, so the sound production is not as precise.
http://static.howstuffworks.com/gif/speaker-bass-reflex.gif
A bass reflex speaker produces two sound waves by moving one driver. When the driver compresses air forward, it rarefies it backward, and vice versa. The second sound wave is emitted from a port at the base of the speaker enclosure.
SOURCE http://howstuffworks.lycoszone.com/speaker4.htm