User manual AEA DECCA TREE

[. . . ] Placement of the array was generally a few feet behind and about eight to ten feet above the conductor's head. The three microphones are panned Left, Center, and Right respectively. Although it is tempting simply to aim the mics straight out from their support braces, it is preferable actually to point the principal axes of the microphones inward and downward, toward the sound source; this is because omnidirectional microphones always tend to become more directional as frequency increases. Because of the relatively close spacing of the outer microphones, the intensity cues necessary for good stereo imaging are combined with sufficient phase information to produce an open, spacious sound and, due to the middle microphone, at the same time maintain a solid central image. [. . . ] When configured in this manner, the center pair provides the articulation for the stereo image, and the two outer microphones generate the spaciousness. As before, adjusting the relative levels and spacing between the microphones also will affect the overall perspective, and the final result is a matter of judgment and preference. When using the Decca Tree, or any spaced-microphone configuration, it is good practice to pay careful attention to the audio quality of the monophonic-sum of the stereo perspective. With omnidirectional microphones, it is very easy for the combined signal to result in an overabundance of reverberation (or indirect sound) for the mono listener. phase) differences at the microphones, some degree of comb-filtering will result. While not as noticeable when heard in stereo, these effects can seriously degrade the sound for those listening in mono. The best way to monitor this effect is by listening to the mono-sum (Left plus Right). If there is too much indirect sound or out-of phase information, it will become immediately evident by a loss of clarity and/or low-frequency information and a rather hollow or unnatural character to the sound. (Another way of checking mono-compatibility is to view the stereo signal on an XY phase display, such as the AEA LD-2020 Stereo Scope. ) If the mono-compatibility is unsatisfactory, the first option is to decrease the spacing between the Left and Right microphones or to increase the signal level of the Center microphone relative to the two side mics. Selecting a different polar pattern for the microphones is another option. Relocating the entire array closer into the sound source also should be considered, particularly if there is an excess of reverberant information. Picture 1. Decca Tree using three 1 meter bars The AEA Decca Tree System Audio Engineering Associates has developed a modular system for configuring Decca Tree arrays. This utilizes our SMP Stereo Microphone Positioners with a central mounting bracket assembly. With our SMP-17 (seventeen inch), SMP-1M (one meter) and SMP-1. 25M (1. 25 meters) bars, several variations are possible. See the comprehensive document "Modular Microphone Positioning Systems: Stereo Bars and Decca Trees" for more information about modularity. The Mini Decca Tree: one SMP-1M (or SMP-1. 25M) bar for the sides and a SMP-17 for the center, configured using our Mini Tree Bracket; this array is very useful for smaller ensembles or when a stereo pair serves as the center pickup. Of course, any combination of SMP bars and Decca Tree Brackets may be configured for other arrays. Additional sliders for the SMP's also may be employed when additional microphones are added to the array. [. . . ] AEA Ribbon Microphones R84 - Studio Ribbon Mic R88 - Stereo Ribbon Mic R92 - Studio Ribbon Mic specifically designed for close micing and guitar RCA Working Reproduction Microphones and replacement parts AEA R44C Microphone - Museum Quality Reproduction Our tribute to the classic RCA 44B using New Old Stock ribbon material AEA 44CX Microphone 6db more output for critical digital recordings AEA 44CNE Microphone Based on RCA LTD production - the same sound but easier to build Modular Studio Microphone Stands and Booms Coles Microphones Since 1983 we have imported and serviced the Coles 4038 studio ribbon microphone and the 4104B, "lip" mic for voice-over work in high noise environments. We sell and service the mics and stock replacement parts. CB Electronics In North America we also represent CB Electronics, a leading worldwide supplier of machine control equipment to the sound-for-picture industry. Their products specialize in professional control of and translation between bi-phase, 9-pin serial and time code machines. [. . . ]