dogman89 發表於 2007-2-12 22:42:58

分音器一問

請問分音器的線路主要由什麼組成(e.g coil , resistor , cap),what is the function of every components?what happen will occurif i use the pro ac 's 分音器 in the other speaker?

SSWONG 發表於 2007-2-13 09:30:27

U CAN'T DO THAT/NOT advice to do that..... unless the value of the coil, resister &cap of proAc is exactly the same as the speaker u 12 put in (rarely happen).

combination of R(resistant) & C (capacitant) can create a high pass filter /low pas filter depend on the way of arrangement...

F=1/2pi(RC) F=cut off frequency

u can get more info in internet just type in hihg pass filter /low pass filter..

Different tweeter & woofer & diffenrent design of box may have different suitable cut off frequency for the drive.... for e.g tweeter A may suit to has hi pass cut off at 2.5kHz, but tweeter B may suit for cut off at 4kHz, then the combination of RC will be different...

u just search from internet for DIY speaker &crossover...then u will get a lot info including some culcalation software...but still got variation during practical...

For more detail on culculation u better learn from shifu here like KK & Modo.

modi 發表於 2007-2-13 09:49:04

Re: 分音器一問

請問分音器的線路主要由什麼組成(e.g coil , resistor , cap),what is the function of every components?what happen will occurif i use the pro ac 's 分音器 in the other speaker?


分音器主要是由電容及電感所組成的,而大家所見到的電阻只是作補償,因為線圈在頻率變動時是會改變阻抗,所以會以電阻作補償。 :D

SSWONG 發表於 2007-2-13 17:34:18

MODI SIR,

常看到分音器所用的电阻是5W/10W,真的需要用到那么大W的电阻吗?

modi 發表於 2007-2-13 22:32:43

MODI SIR,

常看到分音器所用的电阻是5W/10W,真的需要用到那么大W的电阻吗?


是必須的,用最簡單的公式功率是P=VI,在分音器內電流會有幾百mA或以上,而輸出則為幾V以上,所以最好用10W或以上功率電阻。

SSWONG 發表於 2007-2-14 09:48:22

Thank you modi sir,

可能我上次没仔细量(直接在音箱plug上量),看到的是<2V & <1A。。

modi 發表於 2007-2-16 19:34:11

Thank you modi sir,

可能我上次没仔细量(直接在音箱plug上量),看到的是<2V & <1A。。

假設喇叭是87dB/1W/1M時,擴音機便要輸出2.83V,所以不止2V那麼小呢!唔知有沒有人可以改正我的想法呢? :)

modi 發表於 2007-2-16 19:45:00

所以人們常說300B得8W輸出那麼小怎樣去推84dB的喇叭呢?
這都是錯誤的想法,其實是因為大部份300B為了保障自己的產品,
將300B的屏壓降至350V,令到輸出功率細至4-5W,但如果將屏壓加大,那麼300B的壽命便短了,所以DIY的300B一定要比足電啊!
其實要推84dB靈敏度的喇叭是不會難道300B的,
因為膽機是用牛輸出的,所以不會受到喇叭的阻抗變化的影響,
84dB---1W
87dB---2W
90dB---4W
93dB---8W
那麼大家想想家中聆聽環境是否很大,否則90dB已很大聲了,唔知大家認同與否? :D
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