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Home My WebLink About2001 05 14 Consent B State-of-the-Art Automatic Mixer e e e COMMISSION AGENDA ITEM CONSENT X INFORMATIONAL PUBLIC HEARING REGULAR B May 14,2001 Meeting MG~/DEPT@ Authorization REQUEST: The General Services Dep,artment requests the City Commission determine the efficacy and desirability of installing a state-of-the-art automatic mixer to eliminate current problems with the Commission Chambers sound system, and provide a supplemental appropriation for same. PURPOSE: The purpose of this item is to advise the Commission of the current problems with the Commission Chambers sound system, to suggest a solution, and to request funding for necessary enhancements. CONSIDERATIONS: 1. During the past year, several elements of the Commissiolll Chambers sound system have been upgraded to eliminate problems of sound imbalances, feedback, and background interference. 2. Changes thus far have been necessary and cost-effective, but have not entirely solved the aforementioned problems. 3. Audio Systems of Florida, Inc., which is the only company we have been able to find to work on this system, has completed an analysis of the remaining problems, and concludes that our current "mixer" is antiquated and contributing to the problems. 4. The company suggests an upgrade to a modern automatic mixer at a cost of $4,595.00 FUNDING: A supplemental appropriation of $4,595.00 will be necessary to affect this upgrade. e e e May 14,2001 Consent Agenda Item B Page 2 RECOMMENDATION: It is recommended that a supplemental appropriation be approved by the Commission to provide Commission Chambers sound system enhancements, as outlined in the attached report and proposal from Audio Systems of Florida, Inc. ATTACHMENTS: Letter, dated April 24, 2001, from Robert C. Greis of Audio Systems of Florida, Inc. COMMISSION ACTION: ticf'jl t:H: AUU.l.U :>i:> 1 CI\1:> ur rL.un.l.u~J .1.1'''1 ..,.v, ~..;.lc:. ve:;.e:., J _i. 1 '-.... ;,.; I I...,. -,..........111 J A. Audio Systems of Florida, Inc. ~ THE SYSTE~S CONTRACTOR e Apr i I 24. 2001 City of Winter Sp~ings Winter Springs. Florida To: Gene De Marie Re: Commission Hearing Room Sound Reinforcement System Gene: Please allow me to explain the problem we are having with the sound reinforcement system in the Commission Hearing Room. - The remaining original sound system compononts are the mixer and the power amp I if i er. The mixer does just that - a II ows a II the microphones to be mixed to one output. The power ampl ifier boosts the voice from the microphones enough to be converted to air 'movement from the loudspeakers. Any noise that is generated by hum. buzzing or hiss noise within the mixer is ampl ified and fed to these speakers through the power amp\\f\er, a\ot'\g -.t\'tn 'tne ~~,<>\~e\\ ~\'i.~a\, 't\\e \\'\l.~'n~ 'l~'~~. Speech produces certain frequencies within the range of human hearing dependent on the person or gender producing these frequencies. Certain male voices generate lower freQuencies than the female voice. The pitch of the frequencies generated determines the type of voice heard. such as male or female voice. The furnishings in the room determine how well speech wi II be heard and understood (intelligible) as some frequencies ere absorbed by the furnishings while other frequencies are reflected. A room with heavy carpet i ng. curta ins. and acoust jet i Ieee i ling a II ows better Intel ligibi I ity of speech than a room containing marble wel Is and floors such as is tho case in e cathedral. train station, tunnel. etC. This is because the carpet i ng. curta i ns and co i ling t i I es absorb frequenc i es better than merb I e and concrete, The prob I em is that not a II the frequencies are absorbed or reflected equally by the material. e o ORLANDO; lOllS CORPOAATE SQUARE LONGWOOO, FLOAI0A327!O (40713:\2.1985 I FAX 14~7) ~2-CQ27 o TMlPABAV: 12401112NDSTREETN., SUITE 201 LAROO. FLOfUDA :aJ773 (72~) 839-7487/ FAX Inn 535,4063 GTATE CERTiFIEO AUJlM CONTAACTO/\' EF 0000860, NlCET CEFlTIFIC...T10/,,/ · 085059 Q n MYEflS: 13891 JeTPORT LOOP ROAD. BUITE 2 Fr. t,A"ERS, FLORIDA 33913 (1l~1) 788'U~ I FAX (941)1&6'8821 APR-25-2001 10:43 407 332 0227 95% P.01 SENT BY: AUDIO SYS1~MS O~ ~LUHlUA, !N~i 4UI ~~.: u<:<:/i J.\r n - G;,j . U I I V . ., V""'I~., r ,",vI- '" w e Page 'I Apr i I 24. 2001 Devices such as electronic equal izers. are inserted into the signal cha j n of the sound re i nforcement system in order to "equa I i zeit a II the frequencies produced by speech so that each frequency within the human vo ice range is reproduced Clqua II y. Th is method attempts to prov i d6 a neutral reproduction of each voice using the sound reinforcement system. When certain frequencies within this range are ampl jfied through the sound reinforcement system with enough amplification to be regenerated through the microphone and re-amplified through the sound reinforcement system and broadcast through the speakers. in th i s case, the ce i ling speakers. Each time this occurs. ringing (feedback) is the result. Th is is why j t seems like one per son's vo i ce causes feedback wh i Ie another's voice, even at higher volumo levels does not. e We have previously installed in the sound reinforcement system a device known as the Sabine HFeedback ExterminatorH, which suppresses only the frequency causing feedback. This result in a gradual decrease in the feedback frequency volume so the ringing frequency "goes away>> after a few seconds. Each time another microphone is turned on simultaneously in close proximity to the loudspeakers, as is the case in this room, the threshold of feedback is lowered and feedback is more I ikely to occur when speaking. Precise adjustment of each microphone level is required to keep the system under the threshold of feedback (ringing). Misadjustment of any volume level wi II upset this balance. In this room, up to 12 microphones are turned on simultaneously, I f the vo I ume of any microphone (s) is increased beyond that wh i ch has been set to a I J ow norma I va I ums I eve I, the sound re i nforcement system becomes unstable and feedback occurs as is the case in your Commission Room. Because the microphones are in close proximity to the cei I ing speakers, unless someone is at the controls to turn on only the microphone being e APR-25-2001 10:43 407 332 0227 95% P.02 e e e SENT BY: AUDIO SYSTEMS OF FLORIDA! INCj 407 332 0227j APR-25-0110.:40AMj PAGE 3/3 Page It I Apr i I 24. 2001 used. there is 9 poss i b i I i ty of feedback when the microphone vo I ume I eve lis increased. Because we can not separate the loudspeakers from the microphones. a good so I ut ion is i nsta II an automat i c mixer '. rep I ac i ng the present mixer. Because excellent automatic mixers were not avai lablo when this system was installed and it was and, is not practical to employ a person to stand at the sound system cabinet adjusting volume levels. the next best solution was to provide a mixer and adjust the level for close-up speech. As the Convn i ss i oners do not a I ways speak c I oae I y and tend to speak whi Ie leaning back in the chair, it becomes difficult to hear each sufficiently in the audience. The solution which we propose is the installation of an automatic mixer. The IRP DE4080 VOICE-MATIC Autoatic Mixer is the best solution to this chronic problem.. The advanced design of this mixer ensures that, once adjusted, there will not be a need to constant I y make vo I ume I eve I adjustments. Th ism i xer. wh i I e not i nexpens i ve, is one of the very best automatic mixers avai lable in the world, Another advantage of replacing the present mixer IS that hum. buzz and hiss wil I be replaced with higher volume levels and increased intell igibi I ity, The cost for this installation is $4,595,00, I trust that this wi I I allow you to understand the problems encountered with the sound reinforcement system. APR-25-2001 10:43 407 332 0227 95% P.03