Sunday, 15 January 2017

Horn Loudspeaker Exporations

Horn augmentation of sound is a natural occurrence. Ears and vocal chords use them for the perception and creation of auditory elements. This is but the first of what could be a long list of horns found in nature. It is not much of a stretch then to assume the use of horns is helpful in the reproduction of music. In the public address and large venue application they have been used with great success from the begginig of sound reproduction until today. In the home or small venue it has also been used but with less success. This is because what was developed for the large venue was also used in the small. Many horns and related technologies were designed to disperse limited amplifier energy into large volumes of space to accommodate crowds of persons. They employed techniques to provide limited bandwidth to large volumes and to punch dialogue through heavy cinema screens. If you moved from the balcony of a theatre or concert to just in front of a loudspeaker you might expect it to be overpowering. As obvious as this might be this is exactly what has led to the audiophile perception of what horns sound like - harsh and generally without refinement. The majority of horns and drivers available have been developed for PA use.



Some horn devices have been developed for home or small venue application but have been lost or misunderstood as time passed and public awareness went toward less sensitive devices. The Voit/Lowther is one of these. Originally it was a horn driver - not for direct radiation and coupled with a rear horn as it is often used as today. It is no wonder that it developed a reputation as "shouty". Altec theatre horns suffer much the same misapplication in the home. They were designed for large venues. Western Electric collectors fair better as the tricks to get different dispersions were not yet employed on these earlier designed horns. Where does this leave the common person who desires fine music in the home? It seems it leaves them without the most natural of all sound augmentation devices - the horn and so higher distortion devices have traditionally been employed. Paul Klipsch declared that lack of sensitivity equals distortion - it is an axiom which is unavoidable.




This oversight can remedied although there are always concessions. Size and frequency are inevitably related. Researching the quest of horn systems which were designed for small venues revealed often repeated errors, innovations and rediscoveries of lost technologies. Predictably, knowledge was lost as other speaker technology displaced horns. As home application was never the main body of commercial knowledge - these two elements marginalised the development of home horn systems. One of the great exceptions and greatly overlooked horns is the Western Electric 32 horn which was patented in 1935. Not only are the Western Electric 753, which uses this horn, one of the most costly and rare of collectable speakers but musicians and recording engineers used the same horn for near field monitors until it went out of production in 1984 making it perhaps the horn in longest production - ever. This then was a natural starting point when seeking a small horn for average sized listening rooms. The more that came to light about this unusual and well developed horn the more interesting things became and this is primarily because it sounds particularly good.




D.G. Blattner of Bell Laboratories was granted US Patent #1,996,743 for this type horn in 1935. It first became known as the Western Electric 32A and later, when WE was broken up by anti trust legislation, it was licensed to Altec which changed it slightly into the 32B/C, casting it in plastic, shortening it, and adding external braces to make it more rugged for stage touring and roadie handling. Listening comparisons between the two reveal a similar character with the earlier model being dryer and the later being a bit richer. The earlier version was originally used with a phenolic diaphragm known for less extension but more natural vocal range. The plastic horn appears to be an adjustment for the later AL diaphragm which has greater high frequency extension but less rich vocal range. In any case there is no question this little horn has a remarkably natural presentation in the near field and is a pleasure to have in the home. It brings many of the virtues of the horn - nuance and dynamics -  without the harshness and distortions many horns have.

Ladies and Gentlemen  - the 32 horn:





One the more unique horns in Altec's inventory and one of the longest in production. The design originated with Western Electric and was available to Altec as part of the 1938 consent decree that established the firm. 


Western Electric used it with 713 driver in the the 753 Loudspeaker.










Altec used it in systems with the 802 and other 800 series compression drivers. 

The most famous such system was the A8 Voice of the Theatre speaker which was widely used in movie theatres. 



 


It was also used in 9849 studio monitor





The late 70's saw its incorporation in the Model 15 home speaker system. 





A variety of Pro Audio stage monitors used the horn such as thePro R&R Stage Monitor N482 which had a cult following among stage musicians.



We was have incorporated this horn into the Hadron Loudspeaker for the home because of its natural sound field and refined response.

Azzolina Audio Hadron Loudspeaker



Happy Listening



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