25การบันทึกแบบ magnetic record Analogue tape heads Audio signals are sent to a magnetic record head which converts an electrical signal to a magnetic field of varying stength.A model tape head showing one track ...... and a real one
26การใช้อุปกรณ์ในการบันทึกสัญญาณแบบสามหัวเทป The 3 head system A single head can perform both record and reproduce functions, but better quality can be obtained if two separate heads are used, each one optimized for its specific task. In addition, there needs to be a third head to enable the erasing of previously recorded tape. Studio machines therefore generally have 3 tape heads, arranged as follows:The erase head uses a high-level signal from the same oscillator which is used to provide bias for the record head.
27การบันทึกสัญญาณ Mixer The synchronization problem Record heads and repro heads obviously can't physically occupy the same location. An instrument recorded on Track 1 is recorded on tape commencing at the location of the record head.The trouble is, to overdub another instrument on track 2, you have to listen to, or monitor track 1 so you know when to start playing.Of course, if you play back the tape, listen to track 1 off the repro head, and record track 2 with the record head ...
28การบันทึกสัญญาณ ลงเส้นเทป But eight tracks on half-inch tape each havea narrower track width than two tracks on a quarter inch half-track machine.8 tracks on 1/2" - Narrower tracks than ...... 2 tracks on 1/4" tape
29ระดับความแรงของสัญญาณในเส้นเทป This is particularly important for bass response. Low frequencies are recorded deeper in the magnetic oxide medium. At higher tape speeds, narrow tracks can't transfer low frequency information as efficiently to and from the heads, and wider tracks provide more raw data.
30การบันทึกของสัญญาณดิจิตอล Digital Recording How is it different from analogue? For a start there is usually far less technical preparation, such as alignment, bias and EQ. However, linear digital recorders such as reel-to-reel DASH machines, and rotary head Modular Digital Multitracks (MDMs) still require cleaning and maintenance and computer-based systems require the usual house-keeping chores needed for computers.. Two Digital Recordings ... If the numbers can be read accurately, the playback will be identical.
31Mixdown Decks & Devices The master tape or sound file Once all tracks have been recorded on a multitrack and a mix is set up and ready, the final step is the creation of a master tape or sound file. This involves transferring the sounds from multitrack and re-recording them on a separate system.Regardless of the recording formatused, track configuration is usually2-track stereo.However, any trackconfiguration required, such as 5.1or 7.1 channel sound for film soundtracks and multimedia performances can be employed.
32DAT machines are commonly used in many studios as master recorders. Tascam DA40 16-bit DAT RecorderTascam DA45HR 24-bit DAT Recorder
33Analogue Recordersin both 1/4" and 1/2" formats are still used by many facilities. Professional analogue recorders are sophisticated high-quality devices and with proper set-up for bias and replay EQ, quality noise-reduction sytems and professional tape will give excellent results.
34Digital RecordersCD-Rs - recordable CDs - are fast becoming the preferred mixdown medium Mastering on CD-R for many studios. Most CD recorders are 16-bit machines, so recording facilities with 20/24-bit multitrack digital audio face a nasty problem. A 16-bit CD recorder simply truncates the word length and so wipes out any gains made by using the higher quality multitrack.
35การแยกช่องในการบันทึก Any old track will do, won't it? Theoretically, yes. but in practice there are certain things to consider. Look at this typical track assignment for bed track recording on a 24-track:
36การกำหนด เสียงในแต่ละช่องเพื่อการบันทึก Keeping track of the tracksKIKSNHHRT1VOXPNOKBDGTRKick DrumSnareHi-HatsRack Tom 1VocalsPianoKeyboardGuitarScribble strips - A visual indication of track assignments is generally provided by scribble strips on which you can write the names of sound sources with a marker pen.
39การตรวจสอบเสียง Metering Seeing is Believing ...Good hearing discrimination is essential to working with the fine details of sound - you don't have to see a mix. But our sense of hearing is not particularly good at judging levels of sound, because we don't actually perceive levels, we perceive loudness.The actual level of signal passing through various parts of the recording system is a physical quantity which is measureable by a device such as a meter. The loudness of that signal is a subjective phenomenon which varies from person to person
40เท่าไหร่ จึงจะดีRoot Mean Square, or RMSvalue of the audio signal.The RMS value is effectively the equivalent value in DC of an AC waveform. For sine waves only, the RMS value is of the peak value, or roughly 3dB lower than the peak.Engineers using digital technology therefore need metering tools that show precisely what peak level is attained by an audio signal.
41VU MetersVolume Unit meters are averaging devices, usually displaying the Root Mean Square (RMS) value of the signal.Their ballistics (the speed with which they respond to signals) are very different to those of peak meters, with a response time of around 1/3 of a second - similar to that of human hearing.
42PMPO และ RMS ในเครื่องขยายเสียงคืออะไร? PMPO (Peak Music Power Output) เป็นหน่วยวัดของกำลังขับเสียงระดับสูงที่สุดจากทั้งช่องเสียงซ้ายและขวารวมกันสำหรับการขับเสียงในระยะเวลาสั้นๆ โดยไม่ทำให้เสียงเพี้ยน 250 WattsRMS (Root Mean Square) หมายถึงประสิทธิภาพหรือค่าเฉลี่ยของกำลังเสียงที่ขับอย่างต่อเนื่อง หน่วยวัด RMS เป็นตัวบอกที่ดีกว่าสำหรับกำลังขับของเครื่องขยายเสียง 10 Watts