speaker world

Floor-standing speakers

Floor-standing speakers:-Floor-standing, or tower, speakers have been around for years and in many ways remain the standard against which all other speaker types are judged. In general, they

are larger than other types of speakers,

reproduce a wide range of frequencies, including deep bass, and

are usually more efficient, giving you more volume per watt of amplifier power.

Floor-standing speakers tend to be more expensive than other smaller speakers, but they're hard to beat for big, room-filling sound. They're great if you've got a larger room, or if you plan to do a lot of stereo music listening. Check out our articles on choosing speakers for home theater if you plan to integrate them into a larger system, or read about speaker placement for stereo music for helpful tips on positioning to get the best sound in a two-speaker setup.

Piezoelectric Speakers :-Piezoelectric speakers are limited in frequency response therefore they are only used as tweeters or in small electrical devices like watches/clocks to make simple sounds. Piezoelectronics are a solid state technology which makes them durable and good for use as a microphone underwater. These speakers are used as microphones in submarine warfare, they can detect other microphones and hear sounds of other vessels.

Plasma Arc Speakers

Plasma Arc Speakers:-Plasma is ionized gas, or current sent through a gas. Plasma is responsive to electrical fields, therefore you can turn electric signal of sound into an electric field which manipulates the plasma. The plasma does have mass and will vibrate creating sound similar to how a diaphragm moves air to make sound. This kind of speaker is visually quite interesting but limited in sound quality. The speaker has reliability problems and therefore remains just a novelty.

Diaphragm Speakers

Diaphragm Speakers:-This speaker is related to the electrodynamic loudspeaker in that it uses magnetic fields to move an element, however its shape is different. This speaker has the coil directly mounted on the diaphragm. Below is an example of a flat panel style diaphragm speaker. The copper coils have been wrapped around the base of the clear plastic bulges in the photos below. The entire clear plastic sheet below moves to create sound. See the diagram below. This is a heavier speaker than the flat panel speakers above.

Flat Panel Speakers

Flat Panel Speakers:-use voice coils or other apparatus mounted to flat panels to act as the source of sound. The flat panel acts as a diaphragm. Below are some examples of different designs. Different materials can be used as a diaphragm, from vinyl to Styrofoam. This is different from a diaphragm speaker in that the moving voice coil is not wrapped around the same material as the flat panel. The panel part is adhered to the coil assembly.

Standard flat panel electrodynamic loudspeaker have been difficult to make because it is difficult to vibrate the entire flat surface evenly while creating good frequency response. Thus other speaker types have evolved to try to make a flat speaker.

world of the Modern Speaker:

1861 - A simple type of electronic loudspeaker was developed by Johann Philipp Reis - a teacher at Friedrichsdorf, Germany. The speaker was crudely able to reproduce sound and just an experiment.

1876 - Alexander Graham Bell also tried to produce a speaker based on Reis's work.

1877 - The idea of the electromagnetic coil driven speaker is formulated by Werner Von Siemens, he used it with input signals of DC transients and telegraphic signals. He had no way to amplify sound to create a useful speaker, but he theorized that this could eventually be done.

1877-1921 - Various inventors and engineers played with the idea of the electrodynamic loudspeaker but could only create rough distorted sounds. There was no way to electrically amplify the signal to create very loud sounds. The industry continued to rely on more advanced horns to create amplification.

The first modern loudspeaker
Above: The first prototype loudspeaker, finished in May 1921. The speaker cone is damaged. Inside the cabinet is a groundbreaking power amplification system.

RCA was able to collectivize research in order to create better technology. In addition to having a strong US company to compete internationally in the radio market, having better technology was important for the US during escalating war tensions prior to WW2. World War 1 taught the important lesson not to be left behind, and that radio technology could mean the difference between winning or being crushed.

C.W. Rice of General Electric and E.W. Kellogg of AT&T worked together in Schenectady, New York to develop the modern speaker and first electric amplification system. They created a working prototype in 1921. Rice and Kellogg solved the final problems which led to a nice crisp sound. Previous attempts to make the loudspeaker created an unacceptable muffled sounding audio. This muffled sound was not good enough to compete with the horn which was well established in the market. Rice and Kellogg were able to fully understand the reproduction of all the frequencies necessary to create an accurate audio sound. Their prototype had enough of a dynamic range in frequencies to be better than the horn, while possessing the ability to greatly increase loudness (dB). In 1925 they filed for patents and made a speech in St. Louis to the AIEE. After several years of work they perfected it as the first commercial product of it's kind called the Radiola Loudspeaker #104. It sold in 1926 for $ 250 (about $3000 today (US dollars)). The speaker was produced under the company name of RCA.

Above: The first speaker. The coil was stationary unlike modern speakers, the moving magnet was inside. Copper wires were insulated with cloth. This prototype was built by C.W. Rice and E.W. Kellogg in 1921. The speaker worked, but needed improvement to make it smaller so it could fit into radio sets. Within a few years they improved the speaker so it could fit into a radio 20 x 12 x 16" high.

An early speaker in a household radio,
it uses a simple cardboard cone and small amplifier (the transformer)

RCA: The Radio Corporation of America sold the first speaker instead of General Electric because the RCA was created as a consortium of many US companies. RCA was created under pressure from the US government as a way of having the major electric technology companies work together on patents in order to more easily create finished products which could compete with state-sponsored European companies. European companies like Philips and Siemens had a leadership which could easily mobilize patents for creation of products. Under the more true capitalist systems in the US at the time, companies fought over patent royalties and kept secrets from each other.