Stereo speakers

Bose has been selling stereo speaker packages since 1966 and surround sound speaker packages since 1992. Since that time the company has produced a wide range of stereo and surround sound speakers to be powered by a receiver or amplifier.

## Timeline of stereo speakers

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Some names have been abbreviated and at times full names have been shortened to save space
("AM" = Acoustimass; "AMP" = Acoustimass powered; "P AM3" = Powered Acoustimass 3 & "FS 360P" = FreeSpace 360P)
Sources: Bose owners guides
## Stereo speaker packages

Bose has been a manufacturer of stereo speakers since the late 1960s. In the current range, the 201, 301 and 901 systems use the unique design where most of the drivers face away from the listener. The Acoustimass 3, Acoustimass 5, 191, 791 and 161 systems use a conventional design, where the drivers face the listener.

## Overview

During the company's first year in business the Bose Corporation engaged in sponsored research. Amar Bose believes that imperfect knowledge of psychoacoustics limits the ability to adequately characterize quantitatively any two arbitrary sounds that are perceived differently, and to adequately characterize and quantify all aspects of perceived quality. He believes, for example, that distortion is much over-rated as a factor in perceived quality in the complex sounds that comprise music, noting that a sine wave and a square wave (a hugely distorted sine wave) are audibly indistinguishable above 7 kHz. Similarly, he does not find measurable relevance to perceived quality in other easily measured parameters of loudspeakers and electronics, and therefore does not publish those specifications for Bose products. The ultimate test, Bose insists, is the listener's perception of audible quality (or lack of it) and his or her own preferences.
 This reluctance to publish information is due to Bose's rejection of these measurements in favour of "more meaningful measurement and evaluation procedures".

## 2201

Bose's first loudspeaker product, the model 2201, dispersed 22 small mid-range speakers over an eighth of a sphere. It was designed to be located in the corner of a room, using reflections off the walls to attempt to increase the apparent size of the room. Electronic equalization was used to to flatten the frequency spectrum of this system. The results of listening tests were disappointing (a later Bose publication presents theories regarding these results), which led to Bose conducting further research and, ultimately, developing the 901 speaker system.

#### 2201

The "2201" was released in 1966 and was Bose's first speaker system. It consisted of 22 five-inch drivers and was designed to be located in the corner of a room, using reflections off the walls and floor to disperse the sound. The system included tone controls and a switch to attenuate frequencies below 50 Hz. The 2201 was a failure in the market and was discontinued after three or four years.

## x01 speakers

### 901

The 901 Speaker System is a hallmark for Bose and was released in 1968. The speakers were a huge commercial success for Bose, contributing significantly to Bose's rapid growth throughout the 1970s. The "901" was a conventional design consisting of two floorstanding speakers. The system has nine drivers per channel, a separate amplifier unit, and an equalizer.

Unlike other Bose speakers, the 901 Series was not intended to be used without their included 901 Active Equalizer. While the speakers included metal pedestal stands, ceiling mounts were also available.

In the 1990s, Bose manufactured a "Lifestyle 901" system that integrated two 901 speakers, the 901 Active Equalizer, and a Lifestyle stereo receiver that integrated an A/M-F/M radio tuner and a CD player, as well as a remote control.

It was sold until 2016, when the 901 Series VI was discontinued.

#### Design

In researching a successor to the 2201, Bose proposed that a dominance of reflected sound arriving is important in emulating live performances. This led to a speaker design in which eight identical mid-range drivers were aimed at the wall behind the speaker while the ninth driver was aimed towards the listener. The purpose of this design was to achieve a dominance of reflected over direct sound in home listening spaces. The pentagonal design used in the Model 901 was (and remains) unconventional compared with most systems where the mid-range and high-frequency speakers directly face the listener.

An electronic equalizer was implemented by Bose to modify the speakers frequency response. Bose's marketing term for control of acoustics within the cabinet (a fundamental consideration for speakers of any brand) is termed "Acoustic Matrix Enclosure".

### Specifications/Features

* **Nine Full-Range Drivers** – One direct firing speaker and eight rear firing speakers.
* **Active Equalizer** – The speaker set includes an equalizer made specifically for the speakers. This controls frequency outputs to the speakers.
* A special **Acoustic Matrix Enclosure** – This helps reduce speaker chamber noise and to help hear well-defined low frequencies over the low-frequency spectrum.
* **Helically-Wound Aluminum Voice Coils** – These are designed for high durability, greater efficiency and superior power handling.

### 601

The Bose 601 Speakers were first made available to the public in 1977. They were the first Bose speakers to incorporate a technology they used to call Symmetry Control. The Bose 601 Speakers were produced till the late 2004, culminating with the Bose 601 Speakers IV series. Since 1977 till 2004, the Bose company rolled out 4 different models of Bose 601 Speakers.

### 301

The "301" bookshelf speakers were released in 1975 and feature eight-inch (8.0") woofers and larger tweeters than its later 201 counterparts. A wall-mounting kit is available, though these are meant to be bookshelf speakers.

Impedance 8 OHMS
Cabinet,
Height: 17"
Width: 10.5"
Depth: 9.25"
Woofer: 8"
Tweeters: 3"

The Bose 301 Series II is a classic and powerful direct/reflecting speaker system delivering ultra-clear sound with stereo effects of remarkable quality. Direct/Reflecting speaker technology in these Bose stereo speakers lets you experience a live music concert in the comfort of your home. Asymmetrical design of the Bose 301 Series II offers balanced sound effects throughout the room. Integrated 8-inch woofer in this direct/reflecting speaker system provides rich and powerful bass effects. High-sensitivity tweeters of these Bose stereo speakers facilitate wide scattering of the sound, letting you feel the surround effects even if you are at a distance. Dual frequency crossover network in the Bose 301 Series II offers outstanding sound clarity by optimizing output frequencies.

The most recent version, the "301 Series V" has been on sale since 2002.

### 201

The "201" bookshelf speakers were released in 1982. Similar in design to the larger 301 Series, the 201 Series featured smaller drivers (speakers). They feature five-inch (5.0") woofers and small tweeters, and are bookshelf speakers, though a wall mounting kit is also available.

The most recent version, the "201 Series V" has been on sale since 2015.

## "Virtually Invisible" Series

In the early 2000s, Bose introduced the 191 Virtually Invisible in-ceiling/in-wall loudspeakers. These speakers included both round and rectangular speaker grilles that could be installed according to the homeowner's preferences.

The 191 has since been replaced by the "x91 Series" Virtually Invisible in-ceiling/in-wall loudspeakers (which include the 591, 691, 791, and 891 loudspeakers). Unlike the 191, which included two different styles of speaker grilles, the x91 Series included different models made specifically for in-wall or in-ceiling installation. The 691 and 791 are specifically designed to be mounted in a wall, while the 891 is specifically designed to be mounted in a ceiling.

The speaker grilles can easily be painted to match the homeowner's decor, and the 191 Series could also included in a line of "installed" surround-sound systems in new home construction.

## Acoustimass Stereo Speakers

The original Acoustimass bass module featured a wooden ported enclosure round port (which later changed to a new cabinet design with a round port) while the current Acoustimass module features a larger, square port (the Acoustimass 3 and 5 systems still use the older-style Acoustimass module). The cube speakers were recently redesigned with a slimmer profile, and are no longer adjustable. New mounting brackets allow the newly-designed speakers to mount nearly flush to the wall.

In the past, Bose has manufactured a 7.1-channel Acoustimass system, the Acoustimass 16, which featured five "double cube" satellite speakers, a single center-channel speaker, and an Acoustimass bass module.

### Acoustimass 5

The "Acoustimass 5" was released in 1987 and consists of a bass module and two "double cube" satellite speakers. As of July 2019, the Acoustimass 5 currently remains on sale, in the form of the Series V version.

### Acoustimass 3

This "Acoustimass 3" was released in 1989, which consisted of two "single cube" satellite speakers and a smaller bass module.The Acoustimass 3 was discontinued in 2016.

## Environmental Series

First introduced in 1994, the 111 Series Environmental speaker was an indoor/outdoor version of the Model 101 Music Monitor, which was introduced in the late 1980s. The 111 was replaced by the 151, which featured a similar design, but a revised metal speaker grille.

In 2004, the 151 was replaced by the 151 SE, which now featured "Direct/Reflecting" speaker technology for wider coverage, as well as the versatility of vertical or horizontal mounting using the included flush mount brackets.

Also introduced in 2004, the 251 Series Environmental Speaker was a larger version of the 151 Series.

The 131 Marine Speaker was a flush mount speaker that was meant to be installed on a boat, and could be connected to the boat's receiver.

The Freespace 51 is an "in-ground" landscape speaker that features omnidirectional, 360-degree sound projection, as well as a bass port. The speakers are designed to blend in with outdoor landscaping, and the wiring features "Posi-Tap" connectors, so that speaker wiring can be hidden underground.

## Free Space

The Free Space series of loudspeakers are 25 Volt (25 V) or 70 Volt (70 V) loudspeakers designed to be installed in commercial locations, and were first introduced in the 1980s. Speaker designs are essentially identical to their residential 8 OHM counterparts. Seperate amplifier units and volume controls are available, though these lower-wattage loudspeakers can easily be connected to any 25 Volt (25 V) or 70 Volt (70 V) commercial audio amplifier of most manufacturers, with tap (voltage) setting dials on each individual loudspeaker.

## References

1. ↑ Bose Owners Guides. List of stereo speakers powered by a receiver, does not include combination packages, Retrieved November 11, 2009.
2. ↑ http://www.bose.com/controller?url=/shop\_online/speakers/stereo\_speakers/index.jsp
3. ↑ A History of Bose
4. ↑ Amar Bose 1968 AES paper "On The Design, Measurement, and Evaluation of Loudspeakers"
5. ↑ Gadget Guy Review of the Bose Wave Music System
6. ↑ AES paper
7. ↑ 7.0 7.1 Direct/Reflecting speaker technology – the challenge Cite error: Invalid `<ref>` tag; name "DR speaker challenge" defined multiple times with different content
8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Company History: Bose Corporation
9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 Bose 901 loudspeaker By J. Gordon Holt November, 1979 Stereophile
10. ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 Bose 901
11. ↑ 11.0 11.1 11.2 11.3 11.4 11.5 11.6 Sound all around: the new multi-directional speakers‎ Cite error: Invalid `<ref>` tag; name "Sound all around" defined multiple times with different content Cite error: Invalid `<ref>` tag; name "Sound all around" defined multiple times with different content
12. ↑ http://www.massachusetts.edu/uncommonleadership/greenblatt\_conversation.html
13. ↑ Bose Panaray MA12 technical papers
14. ↑ < src="Module:Citation/CS1/styles.css"></>"2201 speakers". *www.bose.com*. Retrieved 1 July 2019.
15. ↑ http://products.bose.com/pdf/customer\_service/owners/og\_901.pdf
16. ↑ < src="Module:Citation/CS1/styles.css"></>"Archived copy". Archived from the original on 2012-12-02. Retrieved 2012-10-21.CS1 maint: archived copy as title (link)
17. ↑ < src="Module:Citation/CS1/styles.css"></>"901 Direct/Reflecting® speaker system". *www.bose.com*. Retrieved 1 July 2019.
18. ↑ < src="Module:Citation/CS1/styles.css"></>"901® Direct/Reflecting® speaker system - Home Stereo Speakers". *www.bose.com*. Archived from the original on 28 September 2008. Retrieved 20 October 2019.
19. ↑ < src="Module:Citation/CS1/styles.css"></>"901® Direct/Reflecting® speaker system series VI". *www.bose.com*. Retrieved 1 July 2019.
20. ↑ Direct/Reflecting speaker technology – the solution
21. ↑ Bose 601 speakers
22. ↑ < src="Module:Citation/CS1/styles.css"></>"Model 301 Direct/Reflecting® speaker system". *www.bose.com*. Retrieved 2 July 2019.
23. ↑ < src="Module:Citation/CS1/styles.css"></>"301® Series V Direct/Reflecting® speakers". *www.bose.com*. Retrieved 2 July 2019.
24. ↑ < src="Module:Citation/CS1/styles.css"></>"201® Series V Direct/Reflecting® speaker system". *www.bose.com*. Retrieved 2 July 2019.
25. ↑ https://www.bose.com/en\_us/products/speakers/home\_theater/acoustimass-10-speaker-system.html?bvstate=pg:2/ct:r#v=am10\_v\_black
26. ↑ < src="Module:Citation/CS1/styles.css"></>"Acoustimass 16 Series II home entertainment speaker system - Bose Product Support".
27. ↑ < src="Module:Citation/CS1/styles.css"></>"Acoustimass 5 speaker system - Bose Product Support". *www.bose.com*. Retrieved 1 July 2019.
28. ↑ < src="Module:Citation/CS1/styles.css"></>"Acoustimass 5 Series V speaker system - Bose Product Support". *www.bose.com*. Retrieved 1 July 2019.
29. ↑ < src="Module:Citation/CS1/styles.css"></>"Acoustimass 3 speaker system - Bose Product Support". *www.bose.com*. Retrieved 1 July 2019.
30. ↑ < src="Module:Citation/CS1/styles.css"></>"Acoustimass 3 Series IV speaker system - Bose Product Support". *www.bose.com*. Retrieved 1 July 2019.

## External links

* Acoustimass 6 series III review
* Acoustimass 10 series III review
* Acoustimass 16 series I review
* Stereophile review of the Bose 901
* Bose.com 901 information