當會議系統(tong)音響設備故障時,該如何是好?現在,小編就為大家簡單的(de)介紹一下,會議系統(tong)音響(xiang)設備在發生故障的(de)時候(hou),該如何去(qu)判斷(duan)和排除。
一、會議系統音響無聲故障的判斷與排除
1、檢查(cha)所有設備是否都已開(kai)啟(qi),各設備的(de)音量控制鈕是否都已調到合適(shi)位置,調音臺上各通(tong)道(dao)路(lu)徑(jing)開(kai)關是否已選通(tong),檢查(cha)各連接線(xian)是否已連接正(zheng)確(que)、可靠。
2、如(ru)(ru)還無(wu)聲(sheng)則(ze)(ze)需逐(zhu)級(ji)檢查(cha)(cha)(cha),可(ke)以從(cong)后(hou)向前(qian)逐(zhu)級(ji)檢查(cha)(cha)(cha),也可(ke)從(cong)前(qian)向后(hou)逐(zhu)級(ji)檢查(cha)(cha)(cha)。從(cong)前(qian)向后(hou)查(cha)(cha)(cha)時,首先(xian)用(yong)(yong)(yong)監聽耳(er)機檢查(cha)(cha)(cha)信號(hao)是否(fou)已(yi)進人(ren)(ren)調音臺,然后(hou)可(ke)以用(yong)(yong)(yong)電壓表(biao)、萬用(yong)(yong)(yong)表(biao)逐(zhu)級(ji)檢查(cha)(cha)(cha),直(zhi)至查(cha)(cha)(cha)出(chu)(chu)無(wu)聲(sheng)的一級(ji)并(bing)判(pan)斷是設(she)(she)備(bei)(bei)(bei)無(wu)輸出(chu)(chu),還是連(lian)線(xian)有問(wen)題。如(ru)(ru)確屬設(she)(she)備(bei)(bei)(bei)故(gu)(gu)障(zhang)(zhang),則(ze)(ze)應更換備(bei)(bei)(bei)用(yong)(yong)(yong)設(she)(she)備(bei)(bei)(bei)以救急;如(ru)(ru)果屬于(yu)周邊(bian)設(she)(she)備(bei)(bei)(bei)出(chu)(chu)現(xian)故(gu)(gu)障(zhang)(zhang),在(zai)沒(mei)有備(bei)(bei)(bei)用(yong)(yong)(yong)設(she)(she)備(bei)(bei)(bei)的情(qing)況下,可(ke)以直(zhi)接將出(chu)(chu)故(gu)(gu)障(zhang)(zhang)的周邊(bian)設(she)(she)備(bei)(bei)(bei)跳(tiao)過。例如(ru)(ru)均(jun)衡器(qi)出(chu)(chu)現(xian)故(gu)(gu)障(zhang)(zhang)了,則(ze)(ze)可(ke)以將輸人(ren)(ren)到均(jun)衡器(qi)的輸人(ren)(ren)線(xian)插(cha)頭拔(ba)出(chu)(chu)來加到后(hou)一級(ji)設(she)(she)備(bei)(bei)(bei)的輸人(ren)(ren)插(cha)座;如(ru)(ru)果是調音臺的某一輸人(ren)(ren)通(tong)道出(chu)(chu)現(xian)故(gu)(gu)障(zhang)(zhang),則(ze)(ze)可(ke)以換一路(lu)輸人(ren)(ren)通(tong)道.直(zhi)到活動(dong)結束后(hou)再更換設(she)(she)備(bei)(bei)(bei);如(ru)(ru)屬連(lian)接線(xian)有問(wen)題,則(ze)(ze)在(zai)急用(yong)(yong)(yong)時先(xian)換備(bei)(bei)(bei)用(yong)(yong)(yong)線(xian),然后(hou)有空時再修(xiu)理設(she)(she)備(bei)(bei)(bei)和連(lian)接線(xian)。對于(yu)設(she)(she)備(bei)(bei)(bei),如(ru)(ru)自己不(bu)熟悉設(she)(she)備(bei)(bei)(bei)內部結構、原理時不(bu)要輕易動(dong)手修(xiu)理,以免(mian)小故(gu)(gu)障(zhang)(zhang)變成(cheng)大故(gu)(gu)障(zhang)(zhang)當(dang)用(yong)(yong)(yong)電容麥克風時,還應檢查(cha)(cha)(cha)幻像電源(yuan)是否(fou)加上。
二、會議音響系統中哼聲大的判斷與排除
哼(heng)(heng)聲(sheng)(sheng)(sheng)(sheng)往(wang)往(wang)是由(you)于(yu)(yu)接(jie)(jie)地(di)(di)不良或(huo)不對,系(xi)統的(de)(de)設備(bei)不在同(tong)(tong)一(yi)路電(dian)(dian)(dian)網上(shang),地(di)(di)電(dian)(dian)(dian)位嚴(yan)重相差引(yin)(yin)(yin)起(qi)的(de)(de),而(er)連(lian)接(jie)(jie)線(xian)的(de)(de)屏蔽層脫(tuo)焊或(huo)屏蔽線(xian)接(jie)(jie)得不對而(er)形成地(di)(di)電(dian)(dian)(dian)流回(hui)路,也會引(yin)(yin)(yin)起(qi)哼(heng)(heng)聲(sheng)(sheng)(sheng)(sheng)大。所以(yi)應著重檢查這些方面,必要(yao)時(shi)應加隔(ge)離(li)(li)用(yong)音(yin)(yin)頻(pin)變壓器(qi),以(yi)便(bian)把前后級設備(bei)間(jian)的(de)(de)“地(di)(di)”斷(duan)(duan)開,而(er)信號仍(reng)然暢(chang)通(tong)(tong)。尤其是在兩個(ge)系(xi)統之間(jian)相連(lian)接(jie)(jie)時(shi),往(wang)往(wang)會由(you)于(yu)(yu)兩個(ge)系(xi)統不用(yong)同(tong)(tong)一(yi)電(dian)(dian)(dian)源(yuan)而(er)引(yin)(yin)(yin)起(qi)兩個(ge)系(xi)統之間(jian)的(de)(de)地(di)(di)電(dian)(dian)(dian)位不同(tong)(tong),有時(shi)甚至(zhi)非(fei)常(chang)嚴(yan)重,從而(er)產(chan)生明顯的(de)(de)哼(heng)(heng)聲(sheng)(sheng)(sheng)(sheng)。對這種原因引(yin)(yin)(yin)起(qi)的(de)(de)非(fei)常(chang)容易(yi)判(pan)斷(duan)(duan),只(zhi)要(yao)將兩個(ge)系(xi)統之間(jian)的(de)(de)連(lian)接(jie)(jie)信號線(xian)插(cha)頭從一(yi)個(ge)系(xi)統拔掉,哼(heng)(heng)聲(sheng)(sheng)(sheng)(sheng)馬上(shang)會消失(shi)。如果確(que)認(ren)哼(heng)(heng)聲(sheng)(sheng)(sheng)(sheng)是由(you)于(yu)(yu)兩個(ge)系(xi)統電(dian)(dian)(dian)源(yuan)的(de)(de)地(di)(di)電(dian)(dian)(dian)位不同(tong)(tong)引(yin)(yin)(yin)起(qi)的(de)(de),則可以(yi)采取將兩個(ge)系(xi)統的(de)(de)“地(di)(di)”隔(ge)離(li)(li)的(de)(de)方法(fa),通(tong)(tong)常(chang)用(yong)加隔(ge)離(li)(li)用(yong)音(yin)(yin)頻(pin)變壓器(qi)來(lai)達(da)到目的(de)(de)對隔(ge)離(li)(li)用(yong)音(yin)(yin)頻(pin)變壓器(qi)的(de)(de)技術要(yao)求是:
①一、二次繞(rao)(rao)組用(yong)同樣規格的(de)導線繞(rao)(rao)制,圈數比(bi)為1:1;
②輸人阻抗和輸出(chu)阻抗均為600Ω;
③諧波失真不大于(yu)10%;
④頻率響應(ying)在40Hz~16kHz范圍內優于士0.5dB;
⑤功(gong)率(lv)最好不小于100mW。
三、會議音響系統中削波失棄的判斷與排除
首先檢查各設(she)備(bei)(bei)(bei)上的(de)(de)削波(bo)(bo)指示燈是(shi)否亮著,如(ru)(ru)并未發現(xian)削波(bo)(bo)指示燈連續亮,則(ze)(ze)可以(yi)選擇系統靠中間的(de)(de)一臺設(she)備(bei)(bei)(bei)把音量降(jiang)低幾個(ge)dB.以(yi)判(pan)斷是(shi)該(gai)(gai)設(she)備(bei)(bei)(bei)的(de)(de)前面(mian)已有削波(bo)(bo)失(shi)真(zhen),還是(shi)在該(gai)(gai)設(she)備(bei)(bei)(bei)后(hou)面(mian)才(cai)產生的(de)(de)削波(bo)(bo)失(shi)真(zhen)。如(ru)(ru)此經過(guo)幾次調節音量控制(zhi)器,即可判(pan)斷削波(bo)(bo)來自哪一級。一般來說,確實是(shi)信號過(guo)強引起的(de)(de)削波(bo)(bo),則(ze)(ze)應在前級設(she)備(bei)(bei)(bei)上就將(jiang)音量電(dian)平降(jiang)下來,如(ru)(ru)屬設(she)備(bei)(bei)(bei)故(gu)障(如(ru)(ru)設(she)備(bei)(bei)(bei)內的(de)(de)工作電(dian)源不正常或負反饋通路開路等)則(ze)(ze)必須(xu)更換設(she)備(bei)(bei)(bei)。
四、會議音響系統中聲音小的判斷與排除
在對各(ge)臺(tai)設(she)備的操作都符合規范的情況下,聲(sheng)(sheng)音小往往是連接(jie)線問(wen)題(ti)(ti)居多。如連接(jie)線短路,插頭、插座(zuo)配合不(bu)好,連線虛焊等,在判定連接(jie)線沒有(you)問(wen)題(ti)(ti)后(hou)再懷疑(yi)設(she)備,檢(jian)查是那一臺(tai)設(she)備有(you)了(le)故障,然后(hou)再更換設(she)備。如聲(sheng)(sheng)音小還伴隨聲(sheng)(sheng)場嚴重不(bu)均勻則應考(kao)慮(lv)揚聲(sheng)(sheng)器(qi)的相位(wei)是否接(jie)錯。
五、會議音響系統中干擾噪聲
有時在一些地區的擴聲系統中可以聽到廣播電臺的聲音,或者其他干擾聲。例如來自雷達、高頻熱合機、電焊機等(deng)的(de)(de)(de)(de)(de)干(gan)擾(rao)(rao)聲(sheng)(sheng),統稱為噪(zao)聲(sheng)(sheng)。有(you)時一套擴聲(sheng)(sheng)系(xi)統安(an)裝完,調(diao)(diao)試時可(ke)能聽到(dao)(dao)音(yin)(yin)(yin)箱中發出(chu)(chu)間(jian)隙性(xing)雜音(yin)(yin)(yin),甚至出(chu)(chu)現廣播電(dian)(dian)(dian)(dian)臺的(de)(de)(de)(de)(de)播音(yin)(yin)(yin)聲(sheng)(sheng),這些聲(sheng)(sheng)音(yin)(yin)(yin)往往是(shi)由于(yu)(yu)空間(jian)有(you)較強(qiang)的(de)(de)(de)(de)(de)(被(bei)(bei)調(diao)(diao)制(zhi)的(de)(de)(de)(de)(de))高(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)磁波,擴聲(sheng)(sheng)系(xi)統接收到(dao)(dao)這些被(bei)(bei)調(diao)(diao)制(zhi)的(de)(de)(de)(de)(de)高(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)磁場(chang)后(hou)產生高(gao)頻(pin)(pin)(pin)感(gan)應電(dian)(dian)(dian)(dian)動勢(shi)—高(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)信(xin)(xin)(xin)(xin)號(hao)(hao),然后(hou)這個高(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)信(xin)(xin)(xin)(xin)號(hao)(hao)通過(guo)擴聲(sheng)(sheng)系(xi)統電(dian)(dian)(dian)(dian)子(zi)電(dian)(dian)(dian)(dian)路(lu)中的(de)(de)(de)(de)(de)例如晶體二極(ji)管、晶體三極(ji)管、場(chang)效應管、集成電(dian)(dian)(dian)(dian)路(lu)等(deng)非線(xian)(xian)性(xing)元器件(jian)構成的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)路(lu)對(dui)高(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)信(xin)(xin)(xin)(xin)號(hao)(hao)進行(xing)解(jie)調(diao)(diao),將寄(ji)(ji)生于(yu)(yu)高(gao)頻(pin)(pin)(pin)信(xin)(xin)(xin)(xin)號(hao)(hao)中的(de)(de)(de)(de)(de)音(yin)(yin)(yin)頻(pin)(pin)(pin)調(diao)(diao)制(zhi)信(xin)(xin)(xin)(xin)號(hao)(hao)解(jie)調(diao)(diao)出(chu)(chu)來,這里(li)高(gao)頻(pin)(pin)(pin)信(xin)(xin)(xin)(xin)號(hao)(hao)相當于(yu)(yu)被(bei)(bei)調(diao)(diao)制(zhi)的(de)(de)(de)(de)(de)載波信(xin)(xin)(xin)(xin)號(hao)(hao),而(er)寄(ji)(ji)生于(yu)(yu)這些高(gao)頻(pin)(pin)(pin)信(xin)(xin)(xin)(xin)號(hao)(hao)中的(de)(de)(de)(de)(de)音(yin)(yin)(yin)頻(pin)(pin)(pin)信(xin)(xin)(xin)(xin)號(hao)(hao)相當于(yu)(yu)調(diao)(diao)制(zhi)波信(xin)(xin)(xin)(xin)號(hao)(hao),如果我們的(de)(de)(de)(de)(de)擴聲(sheng)(sheng)系(xi)統設計(ji)不是(shi)很到(dao)(dao)位,則(ze)可(ke)能將射(she)頻(pin)(pin)(pin)無線(xian)(xian)電(dian)(dian)(dian)(dian)高(gao)頻(pin)(pin)(pin)干(gan)擾(rao)(rao)信(xin)(xin)(xin)(xin)號(hao)(hao)通過(guo)連接線(xian)(xian)較多(duo)地(di)接收進來,然后(hou)由于(yu)(yu)擴聲(sheng)(sheng)設備電(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)(de)(de)非線(xian)(xian)性(xing),將這些高(gao)頻(pin)(pin)(pin)無線(xian)(xian)電(dian)(dian)(dian)(dian)信(xin)(xin)(xin)(xin)號(hao)(hao)進行(xing)解(jie)調(diao)(diao),從而(er)產生可(ke)感(gan)覺到(dao)(dao)的(de)(de)(de)(de)(de)音(yin)(yin)(yin)頻(pin)(pin)(pin)干(gan)擾(rao)(rao)信(xin)(xin)(xin)(xin)號(hao)(hao),最(zui)后(hou)在揚(yang)聲(sheng)(sheng)器系(xi)統中播放出(chu)(chu)來。
解(jie)決這個問題的(de)(de)(de)(de)(de)首要(yao)方(fang)法是(shi)(shi)在系統設計時注(zhu)意采用(yong)平衡(heng)連(lian)接,到功(gong)率(lv)放大器輸(shu)(shu)(shu)(shu)入(ru)端為止的(de)(de)(de)(de)(de)所有音(yin)(yin)頻(pin)(pin)線都應該采用(yong)屏蔽性能(neng)良好(hao)的(de)(de)(de)(de)(de)音(yin)(yin)頻(pin)(pin)電纜,并(bing)且(qie)連(lian)接線的(de)(de)(de)(de)(de)長度不(bu)(bu)要(yao)太(tai)長,接地良好(hao)。在這些措施都到位的(de)(de)(de)(de)(de)情況(kuang)下,還有干擾信(xin)號(hao)出現時,則應該考慮(lv)加入(ru)射(she)頻(pin)(pin)濾(lv)(lv)(lv)波(bo)(bo)(bo)器,目前很多周邊設備的(de)(de)(de)(de)(de)信(xin)號(hao)輸(shu)(shu)(shu)(shu)入(ru)端加有射(she)頻(pin)(pin)濾(lv)(lv)(lv)波(bo)(bo)(bo)器電路,能(neng)對射(she)頻(pin)(pin)信(xin)號(hao)進(jin)行抑制,但是(shi)(shi)調(diao)音(yin)(yin)臺等設備的(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)入(ru)端沒有設置(zhi)射(she)頻(pin)(pin)濾(lv)(lv)(lv)波(bo)(bo)(bo)器電路。考慮(lv)到廣播調(diao)頻(pin)(pin)中波(bo)(bo)(bo)的(de)(de)(de)(de)(de)最低(di)載波(bo)(bo)(bo)頻(pin)(pin)率(lv)是(shi)(shi)535kHz,所以(yi)建議射(she)頻(pin)(pin)低(di)通濾(lv)(lv)(lv)波(bo)(bo)(bo)器的(de)(de)(de)(de)(de)-3dB頻(pin)(pin)率(lv)選(xuan)在400kHz,這樣比(bi)音(yin)(yin)頻(pin)(pin)最高頻(pin)(pin)率(lv)20kHz高了20倍,不(bu)(bu)至(zhi)于影響(xiang)音(yin)(yin)頻(pin)(pin)信(xin)號(hao)的(de)(de)(de)(de)(de)傳輸(shu)(shu)(shu)(shu),當然比(bi)40kHz頻(pin)(pin)率(lv)再低(di)一些也不(bu)(bu)是(shi)(shi)不(bu)(bu)可(ke)(ke)以(yi),但是(shi)(shi)起碼要(yao)在200kHz以(yi)上(shang)。可(ke)(ke)以(yi)用(yong)RC構(gou)成(cheng)阻容(rong)低(di)通濾(lv)(lv)(lv)波(bo)(bo)(bo)器,也可(ke)(ke)以(yi)用(yong)LC構(gou)成(cheng)濾(lv)(lv)(lv)波(bo)(bo)(bo)器,將低(di)通濾(lv)(lv)(lv)波(bo)(bo)(bo)器接在調(diao)音(yin)(yin)臺的(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)入(ru)端,尤其(qi)是(shi)(shi)小信(xin)號(hao)音(yin)(yin)源與(yu)調(diao)音(yin)(yin)臺相連(lian)接的(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)入(ru)口(kou)。