很多人對於瓦數大小是有蠻大的誤解 事實上我之前就有被吐吵過 不過為避免屆時引起不必要的誤解與影響版面的品質所以沒做解釋 不過...anyway 短短幾句... 一般而言 不要以為30瓦的擴大機 音量就會多出15瓦的一倍 事實上差距頂多是3dB而已 那3dB到底是多少? 很多人一天到晚在講dB可是到底是蛇模東西卻又不瞭 事實上聲音的描述是最困難的...無論是講音色 或是音量...簡單來說 1個dB是人耳可察覺音量有不同的最小單位 所以3dB事實上在聽覺上而言並沒有奪大的差距 只是你同時還得考量其他的條件 在你選擇一台擴大機時 包括了他的喇搭尺寸 是不是純真空管...還有許多...甚至是主客觀的條件...有時間再聊吧 現在好像講太多都會被認為在圖利的樣子 總而言之 考量你的預算 考量你的居住環境(不過保證你老媽聽不出來你的15瓦與30瓦有何不同，她不爽還是會幹礁你) 考量日後升級 考量是不是偶而要利用來練團 考量品牌(不同品牌有不同音色個性 就算是小台擴大機也是一樣)
</font><blockquote>引言:</font><hr /> 一般而言 不要以為30瓦的擴大機 音量就會多出15瓦的一倍 事實上差距頂多是3dB而已 </font>[/QUOTE]1個dB的確是是人耳可察覺音量有不同的最小單位,不過News兄講的我不確定是完全對的。 就小弟所知音量差一倍是差6dB好像不是3dB。所以完全看你怎麼想或怎麼感覺了,....你可以說音量差一倍,結果只差6dB而已,換個角度說,....挖...差6dB就已經差一倍了。 假設有一系列的amps真的功率就像廠商聲稱,那100W的確是50W的一倍,但這一倍是不是差很多？就像News兄說的...未必。你都開到最大,或許用表量是差3-6dB,可是人耳可能覺得快聾了,?]而未必真確的可以 說出是差 一倍。 瓦數當然還是有用,小的瓦數在家練習時聲音比較容易做出來,可是拿去做場可能沒有clean,或是聽不太到。大的瓦數做場沒問題,可是你開到3-4就很大聲,可是真正的tube tone 還沒撐到就不好聽。不知道這樣說對不對？ </font><blockquote>引言:</font><hr /> 現在好像講太多都會被認為在圖利的樣子 </font>[/QUOTE]沒那麼嚴重吧？在這裡久了就知道,每三個月辦年就會有人鬧事,要不是攻幹商家就是商家搞互搞,習慣就好...自己聊自己洗歡的。
Folks,.. Get a crystal clear picture before using the "dB"s,,, The decibel "dB" is used to measure sound level, but it is also widely used in electronics and signals.,,,, "dB" is a logarithmic unit used to describe a "ratio"...... The ratio may be power, or voltage or intensity or several other things. For instance, suppose we have two loudspeakers, the first playing a sound with power P1, and another playing a louder version of the same sound with power P2, but everything else kept the same. The difference in decibels between the two is given by 10 log P2/P1 dB.........where the log is to base 10. If the second produces twice as much power than the first, the difference in dB is 10 log (P2/P1) = 10 log 2 = 3 dB. If the second had 10 times the power of the first, the difference in dB would be 10 log (P2/P1)= 10 log 10 = 10 dB. If the second had a million times the power of the first, the difference in dB would be 10 log (P2/P1) = 10 log 1000000 = 60 dB. This example shows one feature of decibel scales that is discussing in sound: they can describe very big ratios in power with numbers of modest size.,,,,,,, "Sound" is usually measured with microphones and they respond (approximately) proportionally to the sound pressure,......... Now the power in a sound wave, all else equal, goes as the square of the pressure.,,,,,, The log of the square of x is just 2 log x, so this introduces a factor of 2 when we convert to decibels for pressures...... The difference in sound pressure level between two sounds with p1 and p2 is defined as: 20 log (p2/p1) dB............where the log is to base 10. When the decibel is used to give the sound level for a single sound rather than a ratio,....then a reference level must be chosen.,,,,, For sound intensity, the reference level (for air) is usually chosen as 20 micropascals, or 0.02 mPa....Nevertheless, this is about the limit of sensitivity of the human ear, in its most sensitive range of frequency. So if you read of a sound intensity level of 86 dB, it means that 20 log (p2/p1) = 86 dB where p1 is the sound pressure of the reference level, and p2 that of the sound in question. Divide both sides by 20: log (p2/p1) = 4.3 dB 4 is the log of 10 thousand, 0.3 is the log of 2, so this sound has a sound pressure 20 thousand times greater than that of the reference level. 86 dB is a loud but not dangerous level of sound, if it is not maintained for very long.......... What does "0 dB" mean? This level occurs when the measured intensity is equal to the reference level..... i.e., it is the sound level corresponding to 0.02 mPa. In this case we have sound level = 20 log (pmeasured/preference) = 20 log 1 = 0 dB So "0 dB" does not mean no sound, it means a sound level where the sound pressure is equal to that of the reference level. This is a small pressure, but not zero. It is also possible to have negative sound levels: - 20 dB would mean a sound with pressure 10 times smaller than the reference pressure, ie 2 micropascals. Not all sound pressures are equally loud. This is because the human ear does not respond equally to all frequencies: we are much more sensitive to sounds in the frequency range about 1 kHz to 4 kHz than to very low or high frequency sounds.... For this reason, sound meters are usually fitted with a filter whose response to frequency is a bit like that of the human ear..... If the "A weighting filter" is used, the sound pressure level is given in units of dB(A). Sound pressure level on the dB(A) scale is easy to measure and is therefore widely used. It is still different from loudness, however, because the filter does not respond in quite the same way as the ear. The ear is capable of hearing a very large range of sounds: the ratio of the sound pressure that causes permanent damage from short exposure to the limit that "undamaged" ears can hear is more than a million...... To deal with such a range, logarithmic units are useful: the log of a million is 6, so this ratio represents a difference of 120 dB...... Psychologists also say that our sense of hearing is roughly logarithmic. In other words, they think that you have to increase the sound intensity by the same factor to have the same increase in loudness.... Whether you agree or not is up to you, because this is a rather subjective question to me.........frankly !!
其實如果把不同設計的擴大機瓦數拿來比大小聲，似乎沒有意義 例如同樣是50W輸出，A類擴大機就會比AB類擴大機夠力 再者除了不同喇叭有不同效率外，尺寸越大的喇叭或者需要越好的低音表現，本來就需要更高的功率來推 除了自身的需求外，一切真的要用試的才知道 回到這個有點大的問題 先縮小到喇叭就好 如果是要在家裡自己彈，要真的好聽，喇叭SIZE不能太小，因為小喇叭大部份是沒低音的。(這是我最不能忍受的) 而如果要再要求一點，可考慮買2個以上的喇叭配置，那種被聲音包圍的感覺真的很爽 還有一點，你房間大小和你能開多大聲真的也很重要 像我房間大概有10坪，fender那種練習amp對於我這種喜歡開"稍大聲"的人來講，真的沒辦法滿足，因為我不喜歡那種聲音被限制在框框裡的感覺(房間大就感覺明顯)，且小amp常常開稍大聲就容易破功。 但如果你只是開小聲在彈，真的不用挑東挑西了... 至於選擇品牌的話，基本上小瓦數且價格貴的(例如15W但要價3萬元)，大部份聲音真的都比較好
"真空管音箱的音色要好聽,音量要很大才可以把真空管的音色給推出來" 這句話我覺得並不完全正確 因為並不是每個真空管音箱都需要操到後級破音 較現代一點的真空管音箱大部分講究的是前級破音 把後級操到破音聲音反而不好聽 這也是為什麼一般Rock或Metal Style的音箱需要用到100以上,老實說真空管後級的100w已經可以開演唱會了 其原因就是要讓音箱有足夠的Headrood 不過可以確定的是要開到一定的音量後級管要讓他有足夠的飽和而喇叭在一定的工作效率下其聲音才會好聽 我的經驗最少大概是要開到四分之一
可以推薦一個30-50W的真空管音箱嗎? 大概需要多少錢才可以買到這個瓦數不錯的真空管音箱? 另外最近看到marshall AVT100,150都有好幾個可供切換的pedal,有沒有其他比較低瓦的音箱也有這樣的pedal呢? 不知道要怎麼選擇,麻煩高手幫忙
GTR1954你可能沒看清楚我所寫的 我再描述一下好了 在其他條件一樣下 一台出瓦數出力大一倍的擴大機她實際的音量差距只有3dB 要有多少dB差別才真的有音量也大一倍的差距呢？ 如果你有看了也了解72講的話 計算一下那要有10dB才會達到音量多一倍之要求 在此也請72先生把你所貼的文章翻成中文以利大家都能清楚 造福群眾 我之前就已經有提過 聲音是最難形容描述的東西 有太朵主客觀的因素會影響我們對聲音或音色的感覺 不過我試相信對一個初學者或是從沒聽過好音箱的人要去跟她描述啥麼是好音色的話 事件很困難的是 如果在再加上他們所聽的音樂又有限的話 那更是難上加難 請別誤會這是有輕視的意味在 大家要知道聲音好壞是要實際去比較出來的 而且我們也應該去多聽更種類型的音樂才有辦法去了解別人在描述的音色是怎麼回事
我來解釋一下好了,dB的算法是將你要的能量大小(P2)除以基準能量大小(P1)再取log乘以10,所以P1的大小就是10dB,兩倍P1就是20dB,60dB就是一百萬倍P1,所以差3dB並不是固定的值,10dB和13dB差約19倍P1 ,50dB和53dB則差十萬倍P1,不過這是能量的算法,人耳聽出來的倍率與能量的倍率並非等比例增加,所以可能能量增加10倍,聽起來卻只增加一倍,這意味著聲音開很大的人收到的能量是一般音量的好幾倍,這 邠O很傷耳朵的.
可不可以不要再談 dB 值ㄌ~~因為太深奧ㄌ!! 還有阿~~人家說30000的琴接上5000塊的音箱,出來的聲音只有5000的價值!! 但是如果都要買50W以上的好音箱的話~~ 那鄰居不就吵死ㄌ~~因為50W以上的音箱,要把音量開到一定的程度,聲音才會讚阿!! 我相信大家都沒有好的隔音設備!! 那到底要不要買好的音箱ㄋ??真是個疑問耶!!!