 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Home Theater Programming Sources
Off-Air TV
Home Theater Surround Speakers -
How Many to Use & Where to Put Them
How Many to Use & Where to Put Them
They just keep adding more; surround speakers that is. The current home theater standard
speaker configuration is 7.1. What does 7.1 mean? It indicates there are 7 full range speakers
and one Low Frequency Effects (LFE) channel in a home theater sound system. There are
always three speakers in the front, the left, center and right speakers (LCRs), unless for some
reason there is no center channel. The four remaining speakers are the surround channels,
and are used to convey environmental ambiance and spatial cues.
With the advent of digital surround formats for the home such as Dolby Digital and DTS Digital,
these surround channels are full range. They can however, be set up to limit the bass
information reaching them by using the setup features in your surround sound receiver or
preamp / processor. In the past, when home theater systems used the Dolby Pro-Logic
surround system, surround speakers were bandwidth limited to 100Hz to 7KHz.
The other change that occurred with the advent of the digital surround formats was that the
surround channels were actually discrete channels. They are recorded and mixed separately
by the sound designer and recording engineers and remain separate when they are put on the
DVD sound track. This dramatically increases the separation between the channels, making
the use of surround speakers much more effective. In the old, analog days, there was only one
surround channel (even though most home theater systems used at least two surround
speakers), and it was placed, out of phase, into the left and right channels when the VCR or
Laser Disc sound track was mixed. The Dolby Pro-Logic processor extracted the surround
channel from the mix. This method of placing the center and surround channels into the left
and right channels is known as matrix encoding. It is still used today, as we'll see in a minute.
Because the surround channels are now full range (20Hz - 20KHz) and discrete, the directors
and sound designers can use them much more effectively to create an acoustical environment.
A sound can actually be placed precisely where the director would like to be for the effect he
or she is trying to achieve. In the first iteration, digital surround sound systems were of the 5.1
configuration, with 3 front channels and two surround channels.
This 5.1 morphed into Dolby Surround EX with "Star Wars: Episode 1 The Phantom Menace",
which was the first movie to feature the new system. With EX, there was a center rear channel
to assist in placing sounds directly behind the listener. In the Dolby Surround EX system
however, that center rear speaker is not a discrete, but is derived, similar to how the surround
and center channels were derived in the Pro-Logic system. Dolby Surround EX is still a 5.1
surround system. In 2001 a digital flag was introduced into the sound track that allowed digital
surround sound processors to recognize the presence of a Dolby Surround EX surround track
and automatically switch into EX mode. Although you'll hear the term 7.1 used to describe
home theater receivers and processors, that is a description of the number of speakers they
support, not the actual surround sound format.
Types of Surround Speakers
There are three main designs of surround speakers:
Where to Put Your Surround Speakers
Proper placement of the surround speakers in a home theater is critical to properly present the
enveloping surround field the director and sound designer of the film worked so hard to create.
With digital surround sound systems such as Dolby Digital and DTS digital, there are two main
speaker configurations; 5.1 and 7.1. The difference is that a 7.1 surround system, will have
speakers placed in the rear of the theater, in addition to the main surround speakers typically
found on the side walls or on the ceiling.
Correct speaker placement for a 5.1 surround system - The surrounds should generally be
placed on the side walls, immediately adjacent to, or slightly behind, the primary row of seating.
They can also be placed on the ceiling if necessary. If placing them on the ceiling, locate them
the same distance from the screen as for side wall placement. As a general rule, they should
be placed 24" above ear level. If you have multiple rows of seating, you can use multiple pairs
of speakers, one for each row. If you are using multiple rows of seating and just one pair of
surround speakers, you can place them midway between the front and rear row.
Correct speaker placement for a 7.1 surround system - Place the side speakers as for a 5.1
surround system. Add a set of rear speakers on the back wall of the theater, approximately 4 -
8 feet apart, depending upon the size of the room and distance to the rear seating. Generally,
the closer the seating to the rear speakers, the closer together they should be to ensure the
sound seems to emanate from directly behind the listener.
speaker configuration is 7.1. What does 7.1 mean? It indicates there are 7 full range speakers
and one Low Frequency Effects (LFE) channel in a home theater sound system. There are
always three speakers in the front, the left, center and right speakers (LCRs), unless for some
reason there is no center channel. The four remaining speakers are the surround channels,
and are used to convey environmental ambiance and spatial cues.
With the advent of digital surround formats for the home such as Dolby Digital and DTS Digital,
these surround channels are full range. They can however, be set up to limit the bass
information reaching them by using the setup features in your surround sound receiver or
preamp / processor. In the past, when home theater systems used the Dolby Pro-Logic
surround system, surround speakers were bandwidth limited to 100Hz to 7KHz.
The other change that occurred with the advent of the digital surround formats was that the
surround channels were actually discrete channels. They are recorded and mixed separately
by the sound designer and recording engineers and remain separate when they are put on the
DVD sound track. This dramatically increases the separation between the channels, making
the use of surround speakers much more effective. In the old, analog days, there was only one
surround channel (even though most home theater systems used at least two surround
speakers), and it was placed, out of phase, into the left and right channels when the VCR or
Laser Disc sound track was mixed. The Dolby Pro-Logic processor extracted the surround
channel from the mix. This method of placing the center and surround channels into the left
and right channels is known as matrix encoding. It is still used today, as we'll see in a minute.
Because the surround channels are now full range (20Hz - 20KHz) and discrete, the directors
and sound designers can use them much more effectively to create an acoustical environment.
A sound can actually be placed precisely where the director would like to be for the effect he
or she is trying to achieve. In the first iteration, digital surround sound systems were of the 5.1
configuration, with 3 front channels and two surround channels.
This 5.1 morphed into Dolby Surround EX with "Star Wars: Episode 1 The Phantom Menace",
which was the first movie to feature the new system. With EX, there was a center rear channel
to assist in placing sounds directly behind the listener. In the Dolby Surround EX system
however, that center rear speaker is not a discrete, but is derived, similar to how the surround
and center channels were derived in the Pro-Logic system. Dolby Surround EX is still a 5.1
surround system. In 2001 a digital flag was introduced into the sound track that allowed digital
surround sound processors to recognize the presence of a Dolby Surround EX surround track
and automatically switch into EX mode. Although you'll hear the term 7.1 used to describe
home theater receivers and processors, that is a description of the number of speakers they
support, not the actual surround sound format.
Types of Surround Speakers
There are three main designs of surround speakers:
- direct firing - A direct firing speaker is like a typical box or inwall speaker. The sound
radiates from one side into the listening room.
- dipole - A dipole speaker radiates sound from two, opposite sides of the speaker
enclosure. The speakers on each side of the enclosure are electrically out of phase with
each other. This causes one speaker to travel out as the other is moving in. This in/out
motion causes some frequencies to cancel each other out so listeners sitting adjacent to
the speaker are in a "null", or cancellation area.
Because of the cancellation, the listeners hear very little direct sound. Most of the sound
heard by the listener is reflected from various surfaces in the room. The net effect is a
very enveloping surround field. This was pioneered by Tomlinson Holman of Lucasfilm to
recreate the array of surround speakers found in a typical cinema using only two
surround speakers.
- bipole - A bipole is physically identical to a dipole but is wired differently. In a dipole
surround speaker the speakers are wired in phase electrically, so the speakers on both
sides of the cabinet move in and out simultaneously. This eliminates the "null" or
cancellation area found when using dipole surround speakers.
Where to Put Your Surround Speakers
Proper placement of the surround speakers in a home theater is critical to properly present the
enveloping surround field the director and sound designer of the film worked so hard to create.
With digital surround sound systems such as Dolby Digital and DTS digital, there are two main
speaker configurations; 5.1 and 7.1. The difference is that a 7.1 surround system, will have
speakers placed in the rear of the theater, in addition to the main surround speakers typically
found on the side walls or on the ceiling.
Correct speaker placement for a 5.1 surround system - The surrounds should generally be
placed on the side walls, immediately adjacent to, or slightly behind, the primary row of seating.
They can also be placed on the ceiling if necessary. If placing them on the ceiling, locate them
the same distance from the screen as for side wall placement. As a general rule, they should
be placed 24" above ear level. If you have multiple rows of seating, you can use multiple pairs
of speakers, one for each row. If you are using multiple rows of seating and just one pair of
surround speakers, you can place them midway between the front and rear row.
Correct speaker placement for a 7.1 surround system - Place the side speakers as for a 5.1
surround system. Add a set of rear speakers on the back wall of the theater, approximately 4 -
8 feet apart, depending upon the size of the room and distance to the rear seating. Generally,
the closer the seating to the rear speakers, the closer together they should be to ensure the
sound seems to emanate from directly behind the listener.
Home Theater Surround Speakers
1 Touch Movie.com
Copyright 2004-7 1 touch movie.com
Home theater and Automation Guide
All rights reserved.
Home theater and Automation Guide
All rights reserved.
| LOOK! Great Deals on Factory Refurbished LCD TVs Save Up to 50% Now! |