十仔相位問題

hammer

各位師兄,我見市面上大多數有三類型設計嘅十仔,一係可以無段式360度任你調節,一係有四個相位,如0、90、180、270,同埋得兩個相位( 0 & 180),到底調節相位點解會影響到十仔有唔同嘅表現,而無段式相位又係唔係最好,但製作又最昂貴呢?可唔可以解釋吓係咩原因令到十仔有唔同效果呢?

澳門客

0 & 180是相位正反控制，用以配合主喇叭低頻的相位，並非分頻點

hammer

澳門客 發表於 2012-5-29 03:55
0 & 180是相位正反控制，用以配合主喇叭低頻的相位，並非分頻點

多謝師兄提醒，已經改番標題及內容

chung190030

師兄可參考以下呢段內容：

Quote from: http://www.soundoctor.com/whitepapers/subs.htm


FIXING THE GROUP DELAY

We CANNOT change (or fix) the inherent group delay in modern subs. That leaves us with two choices IF WE ARE INTENDING TO BE FANATIC !

OPTION 1)  We can move the sub closer to our body about 9-10 feet or so, and then use the phase control on the sub itself to fine tune the match. This is not necessarily as crazy as it sounds. We do this successfully in studios all the time. Of course this might not work in your particular room.

OPTION 2)  We must introduce an equivalent delay TO THE TOP (mains) to match the inherent delay in the sub; then we can super fine-tune the match by using the phase knob on the sub.

Some notes about phase knobs: If you have a SWITCH on a sub labelled "phase" that is wrong. It is not phase; it is POLARITY. Phase is ANY NUMBER of degrees shifted, from 1 degree to 360 degrees to 3600 degrees and so on. Polarity is either 0 degrees or 180 degrees, period. (see Fig.1 and Fig.3 above)  If you have a phase KNOB on a sub, the circuit is usually designed to only ADD DELAY. You cannot take away the inherent delay in the entire electro-mechanical physics of the sub, but you can ADD further electrical delay. Some subs are calibrated in electrical degrees of waveform at 80 hz, because 80 hz is ALWAYS the magic frequency. Therefore IF the knob says 180 degrees it is actually adding 6.25 msec of delay to the sub signal; this is the equivalent of moving the sub 7 feet FURTHER AWAY.

So how do we add delay to the "top"? We would have to introduce a real processor to do that. The options are a device like the DEQX, the Lyngdorf, or the Mcintosh version, here. There is also the BSS Studio processor here. All of these are audiophile grade devices. That means that UNLIKE all the "digital" speaker gadgets intended for use in nightclubs and rock n roll systems, these do NOT operate at 44kHz, (or even 48kHz) and you will NOT be disappointed with what the "processing" has done to your precious highs. Many of the so-called "professional" units are perfectly suitable for a noisy bar or a rock touring PA system but you might be very disappointed if it is your intent to use them in a critical audiophile listening/monitoring situation. That means beware of $99 - $299 processors.

In the instance of Home Theater processors, there is an easy method. We can take advantage of the somewhat flawed concept of "speaker distance settings" to perfectly fix the sub timing issues. Simply set ALL the top speakers ( L C R Ls Rs) to 7 feet where they belong, and set the sub distance to 18-19-20 feet.Now, because all consumer equipment operates backwards (!!!) you are introducing 10 msec delay TO ALL THE TOP SPEAKERS. Now you can fine tune the phase control on the sub to add a bit more delay to perfectly match the mains and the results should be spectacular. My test CD and the two different procedures to accomplish this are all carefully explained here: www.soundoctor.com/testcd.

Once you correctly place the sub(s) in your room so they correctly couple to your desired area, cross over the mains to the sub correctly, and correct the timing issue your results will be everything you hoped for.

cello13814

chung190030 發表於 2012-5-30 10:43
師兄可參考以下呢段內容：

Quote from: http://www.soundoctor.com/whitepapers/subs.htm

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