調校分頻點一問。

patrick12345

小弟睇到現在睇晒各 CHING 既資料,
首先想講講, LFE 的確可以在前/中/什至後置出聲的, 就以我用緊 AV7005 前級為例,
佢在 LFE 既 SETTING 係有 2 項的, 一個係 LFE 只比 SUB 出, 一個係 LFE+MAIN,
即是 LFE 會在 SUB, 同埋全部 SPEAKER 出聲。
我試過明顯地 LFE+MAIN 出來的 BASS 係豐富好多的。

但我又有另一個問題, 我現在一直都係用 LFE+MAIN, LFE 分頻就係 80,
睇了各 CHING 資料我昨晚就試將佢 SET 到 120,
如我沒有理解錯誤, 咁即是以前我的 SUB 就是出 LFE 20 - 80,
而現在的 SUB 就是出 20 - 120, RIGHT?  照計應該 BASS 會更強。

但唔知點解, 我將 LFE 分頻 SET 到 120 的時候, BASS 反而係明顯的弱了....
大家話點解呢？ ((各喇叭 的 CROSSOVER 一直沒變在 80))

SUB 係 SVS U13 郵筒, 已 SET CROSSOVER BYPASS

Big_McIn

但我好似無話subwoofer set 80HZ，就令LFE 內的 80-120HZ消失。
maskedtsang 發表於 2011-3-17 17:25

A. 首先我要交代一吓，當你上載此回覆時，本人正編輯帖子，以下是編輯後的內容：
    Subwoofer 1ch: Audio signal is outputted from SW1 jack only.
    2ch: Audio signal is outputted from SW1 and SW2 jacks (default).
    Select if no subwoofer is connected.
    Front*1 Full Band, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz(THX) (default), 90Hz, 100Hz, 120Hz, 150Hz, 200Hz
    因當選用Subwoofer時，Front Spk and center均可選Full Band，那是否意味有LFE呢？Onkyo無交代。
    2. to filter out unwanted hum。
    a. 那又是否意味81~120Hz是討厭的Hum。
    b. 假設Front and center選Full Band時有LFE，此filter是否濾去LFE source或只是在subwoofer ch 的LFE。
    以上a.和b.又是謎。

B. 非常欣賞閣下的熱心，致函Onkyo求証。
Onkyo(e.g.5508)Subwoofer設定我知只有：
1. 1ch, 2ch, No。
2. LPF of LFE(Low-Pass Filter for the LFE Channel)80Hz, 90Hz, 100Hz, 110Hz, 120Hz。
閣下認同：「只是subwoofer的響應只在20-80HZ，所以80-120HZ流失是無錯的。」
以上都是意會，不要太執著。

C. 本人亦搜集數大廠商，其產品在處理LFE的手法，簡述如下：

1. Lexicon MC12 HD
LFE ON, OFF
Activates and deactivates the Main Zone audio output connector labeled LFE when a custom speaker setup is selected.
When a custom speaker setup is selected:
• Select ON to activate the LFE output connector. LFE information is sent to the LFE output connector.
• Select OFF to deactivate the LFE output connector. LFE signals are redirected to the SUBWOOFER L/R output connectors. If the SUB L/R parameter is set to OFF, LFE signals are redirected to the speakers with the lowest crossover point – unless the 5.1mc BYPASS listening mode is activated. In this instance, configure the speaker setup with the associated DVD-A/SACD player to redirect low frequency signals. When a THX speaker setup is selected, the LFE information is redirected to the SUBWOOFER L/R output connectors, and the LFE parameter cannot be adjusted.

玩Multi Subwoofers，其中一隻專出LFE。
http://173.203.156.112/Uploads/F ... MC-12HD_UG_Rev0.pdf

2. Cary Audio 11a
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.
有關LFE隻字不提。
http://www.caryaudio.com/pdfs/manuals/Cinema11a_manual.pdf

3. Anthem D2v
Advanced Settings – Bypass LFE Crossover
If you have set SUB/LFE XOVER to much lower than 80Hz, the upper portion of the LFE signal will be lost. With BYPASS LFE XOVER set to Yes, LFE goes to the subwoofer without going through the crossover, preventing loss of LFE information.
玩Bypass LFE
http://www.anthemav.com/products/anthem-statement/processor/d-2v

總括來說：

1. LFE 81~120Hz這範圍看來無好過有。
2. 不同品牌和機種，其內置firmware處理LFE都不同。

所以Subwoofer 80Hz設定，並非100%確定LFE內81~120Hz訊息會消聲匿跡，要視乎廠家firmware設定，消費者很難查核。   
以上本人見解，自始至終都是一樣。

Big_McIn

佢在 LFE 既 SETTING 係有 2 項的, 一個係 LFE 只比 SUB 出, 一個係 LFE+MAIN, 即是 LFE 會在 SUB, 同埋全部 SPEAKER 出聲。
patrick12345 發表於 2011-3-17 22:35

你誤解了。

Marantz AV 7005:
Bass Setting
Set subwoofer and LFE signal range playback.
Subwoofer Mode : Select low range signals to be reproduced by subwoofer.
• LFE : The low range signal of the channel set to “Small” speaker size is added to the LFE signal output from the subwoofer.
• LFE+Main : The low range signal of all channels is added to the LFE signal output from the subwoofer.
• Select “LFE+Main” if you want the bass signals to always be produced from the subwoofer.

waicsl

A. 首先我要交代一吓，當你上載此回覆時，本人正編輯帖子，以下是編輯後的內容：
    Subwoofer 1ch: Aud ...
Big_McIn 發表於 2011-3-18 04:33

Big兄,Lexicon MC 12 HD & Anthem D2v两台Processor 價錢都唔野小，可以買幾台5508了，當然有的功課交  
而以討論角度來看，對於LPF set 80Hz時，LFE 81~120Hz範圍失掉一事，真的就如Big兄所言，視乎不同品牌和機種，情況便有所不同
Big兄真做到「終生搜尋 為己為人」

maskedtsang

A. 首先我要交代一吓，當你上載此回覆時，本人正編輯帖子，以下是編輯後的內容：
    Subwoofer 1ch: Aud ...
Big_McIn 發表於 2011-3-18 04:33

我唔知點解師兄可以只是Highlight 我果兩句說話來回應，可能呢D係 Admin.的權限！不過我在上一個post 講呢兩句，只是澄清我要表達的意思，並不是針對任何師兄的言論，請勿對號入座！因為 subwoofer crossover set 80，同 bbsai 師兄所講 subwoofer 所舉例子， subwoofer 響應為 20-80Hz 是有分別吧！我亦不是執著LFE 80-120是否消失，只是見到呢個 post 幾有興趣，所以回應一下。而bbsai 師兄的例子有提起上述問題，我才就些回應。如果有師兄感到不安，敬請諒解！
Front & center 設定為 Full band，點會想像為連LFE的訊號也出埋，唔明！
to filter out unwanted hum，LFE 80-120HZ 輸出到 subwoofer 會有可能引致某些 subwoofer有 hum，而不是 LFE 80-120HZ一定引致有 hum，所以先有Low pass filter for LFE 這個設定。這個不是迷！

謝謝！

Big_McIn

......以我有限英文所理解(哈！).......crossover的設定，從英文亦可得知，是從分頻點以下的都交給subwoofer。.....但照英文用字filter一詞可以明白。.......
maskedtsang 發表於 2011-3-17 14:08

我唔知點解師兄可以只是Highlight 我果兩句說話來回應，可能呢D係 Admin.的權限！
maskedtsang 發表於 2011-3-19 12:08

1. Highlight 說話來回應，個人理解每一位版友都可以做。

2. 本人在這帖亦是抱着討論態度，追尋LPF 在Sub set 80Hz 時(亦即Sub音頻是0~80Hz)，LFE 80~120Hz失掉是否必然的道理，討論時簡化文字運用，但並無故意曲解版友言論，倘若「執著」一詞令人不安，本人謹此向管理層致歉。

FRONT L/R FULL, 40 to 120HZ
Allows the manual selection of a cross-over point for the Main Zone audio output connectors labeled Front L/R. Available selections include FULL, 120 Hz, 100 Hz, and 80 Hz to 40 Hz in 10 Hz increments.
Select FULL to send a full-range signal to the front speakers. Otherwise, select the cross-over point closest to the -3dB low-frequency rating of the front speakers.

SUB/LFE LPF (LOW-PASS FILTER) 40 to 120 Hz
Identifies the cross-over frequency setting below which sounds that may be available from an LFE track are sent to the subwoofer.
Available selections are 120 Hz, 100 Hz, and 80 Hz to 40 Hz in 10 Hz increments.
SUBWOOFERS 0, 1, 2
Selects the number of subwoofers in the system. Available selections are 0, 1, or 2. The 0 selection is only available if the Front Left &
Right speakers are set to FULL.
SUB HPF (HIGH-PASS FILTER) 15, 20, 30, 38 Hz
Identifies the cross-over frequency setting above which sounds are sent to the subwoofer. As a general rule of thumb, the larger the
subwoofer driver, the lower the frequency should be of the Sub HPF parameter. The available selections are 15, 20, 30, and 38 Hz.
**Quoted from the manual of Lexicon MV 5.**

Onkyo(e.g.5508)Subwoofer設定我知只有：
1. 1ch, 2ch, No。
2. LPF of LFE(Low-Pass Filter for the LFE Channel)80Hz, 90Hz, 100Hz, 110Hz, 120Hz。

根據以上美國品牌說明書和Onkyo Subwoofer的設定，可得以下私人見解：
A. Subwoofer設定一般都是LPF，除非像MV5指明有SUB HPF，故此本人所說Subwoofer 80Hz設定，就相等「subwoofer的響應只在20-80HZ」的80Hz實際設定。
B. Identifies the cross-over frequency裏cross-over也可以用來禪釋Front L/R和SUB/LFE LPF設定，cross-over和filter並非分別這麽大。

3. 其他有關本人對Onkyo產品，說明書內敍述不足，這是本人對Onkyo的謎，故此表達出來。

chhanthony

我試過O係我部C11a crossover中嘅SW set做full 會連前置嘅background music 都出埋

bbsai

anthony ching 提供dobly 官方文件中, 有關LFE 81-120Hz
我估計有一個可能, 若果用write program concept 流程,

Subwoofer condition
1, 首先部amp會detect有無subwoofer.
2, 若果”有” subwoofer, 就只會把LFE 送去subwoofer.
3, 不過送之前amp內會要睇吓LFE Low pass filter set幾多 (80/90/100/120) ?
假設set 120Hz, 把一整條LFE (Dolby case), 送去subwoofer.
4, 當subwoofer收到Dolby LFE, 第一件事係睇吓band pass filter set 幾多?
假設set 80Hz:
I/P signal (120Hz 留下Dolby LFE)
O/P signal (80Hz留下 Dolby LFE)
最後結果都只能聽有80Hz留下 Dolby LFE.

“No” Subwoofer condition
1, 首先部amp會detect有無subwoofer.
2, 若果”無” subwoofer, 就只會把LFE 送去FL/FR.
3, 不過送之前amp內會要睇吓FL/FR cut-off freq. set幾多 (Full/40/50/60/70/80/etc…..) ?
假設set Full band, 把一整條LFE (Dolby case), 送去FL/FR.
4, 問題開始出現…若果係咁….
本身FL/FR (0-120Hz) 會和LFE重疊, 還是會抽起FL/FR (0-120Hz), 用LFE取代??

難得大家討論技術問題, 希望可以開心討論吓.
^^

bbsai

我試過O係我部C11a crossover中嘅SW set做full 會連前置嘅background music 都出埋
chhanthony 發表於 2011-3-19 13:15

哈~咁結論係點呀??
anthony ching

Big_McIn

我試過O係我部C11a crossover中嘅SW set做full 會連前置嘅background music 都出埋
chhanthony 發表於 2011-3-19 13:15

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 or Full range. 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.

Anthony:

在這處可否找到答案。

我無11a在手，好難求証。