再玩Room Analyzer

chhanthony

噚晚有幾位網友上咗我度家訪，畀咗唔少意見，試下改改啲setting之後再用xtz度一次，今次條curve好似平返少少，但未實際睇戲去試。

sub-woofer


Front


Sub-woofer + Front (SUb-woofer volume: 11 o'clock Polarity: positive Phase: 0 degree Front crossover: 80hz Sub-woofer crossover: 80hz)


Sub-woofer + Front (SUb-woofer volume: 10 o'clock Polarity: positive Phase: 0 degree Front crossover: 80hz Sub-woofer crossover: 80hz)


RTA: Sub-woofer + Front (SUb-woofer volume: 10 o'clock Polarity: positive Phase: 0 degree Front crossover: 80hz Sub-woofer crossover: 80hz)


Full Range: Sub-woofer + Front (SUb-woofer volume: 10 o'clock Polarity: positive Phase: 0 degree Front crossover: 80hz Sub-woofer crossover: 80hz)

ryanytwong

嘩, 好專業呀

louis001

其實想請教下師兄 係咪真係會有分別 有機會小弟都想黎見識下 學下野
好似對set 音場幾好玩咁 呢辨我係門外漢 但都真係有興趣想研究下 如果師兄下次有局同就到時間 可以預埋小弟麻

chhanthony

louis001 發表於 2013-7-2 12:12
其實想請教下師兄 係咪真係會有分別 有機會小弟都想黎見識下 學下野
好似對set 音場幾好玩咁 呢 ...

分別一定會有，問題條curve係平，但用家啱唔啱聽係一回事。

mantam121

睇圖2,3 (Sub-woofer + Front ),條Curve都好平直.
師兄改左D乜野setting,至得出條靚Curve.

chhanthony

mantam121 發表於 2013-7-2 18:31
睇圖2,3 (Sub-woofer + Front ),條Curve都好平直.
師兄改左D乜野setting,至得出條靚Curve.{:6_22 ...

噚晚試過用下面條curve去睇戲真係無令到低頻唔見晒，真係唔見晒

Sub-woofer + Front (Sub-woofer volume: 10 o'clock Polarity: positive Phase: 0 degree elf: -8dB Front crossover: 80hz Sub-woofer crossover: 80hz)


之後要將sub-woofer嘅volume校返去12點位，先至有返正常嘅低頻

Sub-woofer + Front (Sub-woofer volume: 12 o'clock Polarity: positive Phase: 0 degree elf: -8dB Front crossover: 80hz Sub-woofer crossover: 80hz)



Full Range


RTA


睇到就算我將sub-woofer volume加大都只係會令到16hz至5Xhz音量增加，6Xhz打後係無提升。但如果我喺phase唔改變但將Polarity由positive換成negative的話，60hz會boost得好厲害。

Sub-woofer + Front (Sub-woofer volume: 10 o'clock Polarity: negative Phase: 0 degree elf: -8dB Front crossover: 80hz Sub-woofer crossover: 80hz)


所以我相信如果將polarity set做positive係out of phase，但假設我唔能夠用EQ去削平63hz，你地會揀用out of phase而得到較平嘅curve定係會用要一個有高peak嘅in phase setting?

mantam121

chhanthony 發表於 2013-7-3 12:21
噚晚試過用下面條curve去睇戲真係無令到低頻唔見晒，真係唔見晒

Sub-woofer + Front (Sub-woofer volume ...

out左phase咪變左同其他聲道吾同步囉，冇曬低頻效果 　

chhanthony

mantam121 發表於 2013-7-3 23:50
out左phase咪變左同其他聲道吾同步囉，冇曬低頻效果 　

似係，又似唔係，有時間會詳細講講

呢個係最新嘅圖，但未有機會試戲

jackt

好明顯63Hz附近有兩個dip，但63Hz就似係room mode，如果用同相，dip係改變不大的，但改用反相的話，亦只會令到個room mode加大好多。以room correction來說，應該以減為原則，即盡量減去room mode的干擾，將63Hz的RT60降低於0.5s。
P.S. 小弟最近開始玩XTZ的Room Analyzer。

chhanthony

用了xtz 的Room Analyzer II Pro約三星期，和Cary Audio C11a及JL Audio F110搏鬥了超過二十個鐘，只可以說:"Cary Audio 你可玩得我透了"，一直不明白為可音壓在120hz左右會下跌得這樣厲害，到最後:-

Front crossover: 80hz，Sub-woofer crossover: Full， sub-woofer gain: 12 o'clock， Phase: 0 degree，Polarity: negative，elf: - 8dB，Distance: 10'



Front crossover: 80hz，Sub-woofer crossover: Full， sub-woofer gain: 12 o'clock，sub-woofer level: - 5dB， Phase: 0 degree，Polarity: negative，elf: - 8dB，Distance: 10'



Front crossover: 80hz，Sub-woofer crossover: Full， sub-woofer gain: 11.5 o'clock，Phase: 0 degree，Polarity: negative，elf: - 8dB，Distance: 10'



Front crossover: 80hz，Sub-woofer crossover: Full， sub-woofer gain: 11 o'clock，Phase: 0 degree，Polarity: negative，elf: - 8dB，Distance: 10'



根據Cary Audio C11a的usual manual在crossover一項有這樣的指示:

[SET CROSSOVER POINTS

The LPF/HPF (Low Pass Filter/High Pass Filter) Crossover menus are used to independently set
the internal High Pass filter of the Cinema 11a each of the speakers.

Setting the Speaker Crossover Points
In the Cinema 11a, the Crossover Points can be selected in 10Hz increments within a 40Hz to
150Hz range, or each speaker can be set to receive full range signal. Select the crossover point
closest to the low-frequency rating of the associated speaker. For instance, set to FRONT L/R
parameter to the crossover point closest to the low-frequency rating of the front speaker.

Select the subwoofer crossover point equal to the lowest crossover point of the other speakers.
In general, low frequencies will be redirected from the speakers with the highest crossover points
to the speakers with the lowest crossover points. Low-frequency signals lower than the lowest
crossover point will be redirected to the subwoofer. ]

根據以上示指，假設最底的crossover是Front Speakers，而Front Speakers的crossover point為60hz，那sub-woofer的crossover亦應設定為60hz。不過最尾一句又好像是說到最後低過最低分頻點的低頻會被送到sub-woofer。

十分奇怪的是如在Cary Audio將Sub-woofer的crossover設定在"Full"以外其他所有crossover 組合，包括Front crossover: 40hz、50hz、60hz、70hz、80hz，Sub-woofer crossover: 40hz、50hz、70hz、80hz、100hz、120hz、150hz等在120hz會出現衰減情況，奇怪的是如sub-woofer的crossover設在80hz甚至是50hz理應不會涉及120hz的。

值得注意的是在做Room Analyzer時用的是2.0訊號以Analog入Cary Audio C11a的7.1 Analog input，之後經Cary Audio C11a的DSP做Bass Management的工作，所以如果Cary Audio C11a的Sub-woofer crossover是類似LPF of LFE的話，即是Sub-woofer crossover只會是對.1(LFE) channel有影響，Sub-woofer crossover point的設定應該不會對Room Analyzer有所反應。但事實上Cary Audio C11a的Bass Management有點不同。

如將sub-woofer的crossover設在Full的話120hz是不會像其他的設定有所衰減。之前在實際播放電影時亦發現將Sub-woofer crossover設為120hz的話低頻明顯比80hz或60hz時豐滿。以下為其他crossover設定時的curve:-

crossover: 40/40



crossover: 50/50


crossover: 60/60


crossover: 70/70


crossover: 80/80


crossover: 80/100


crossover: 80/120


crossover: 80/150


看似是Cary Audio C11a的問題，但試將sub-woofer的crossover設為Full而在JL Audio的crossover filter作過濾，但出來的curve又怎樣呢?

crossover: 80/Full JL filer: 0 -12dB


crossover: 80/Full，JL filter: 80 -12dB


crossover: 80/Full， JL filter: 100 -12B


crossover: 80/Full， JL filter: 130 -12B


先用這個設定Front crossover: 80hz，Sub-woofer crossover: Full， sub-woofer gain: 12 o'clock， Phase: 0 degree，Polarity: negative，elf: - 8dB，Distance: 10' JL filter:off 。









之後以十分細的音量(因為已是零晨一時)將所以Power Amplifier 關掉只剩sub-woofer，但當用耳仔貼近sub-woofer是會聽到微弱的人聲，不明白為可LFE會有人聲，如果是由Front Speaker傳來的，在80hz crossover的設定下人聲亦不應傳到sub-woofer，今晚會實際用電影試一下效果如何。

老實說，用了Room Analyzer後才知道Cary Audio C11a的crossover setting是如此特別。


原文: http://chhanthony.blogspot.hk/20 ... -audiojl-audio.html