Keyboard Magazine "In The Studio" UDERSTANDING S.M.P.T.E.
I’ve dedicated this month’s column to SMPTE ( Society of Motion Picture and Television Engineers ) so that the readers of Keyboard Magizine can having a better understanding of this most perplexing subject. First, SMPTE in relation to timecode, is based around a twenty- four hour clock. It divided up into hours, minutes, seconds like a clock and frames ( a division of seconds ) and lastly subframes ( a divsion of frames ). In 1967 the Society of Motion Picture and Television Engineers can upon a standard assistment for the value of one frame. They agreed that a second would be broken down into 30 frames meaning that each frame would equal 1/30 th of a second. A subframe would be a division of a frame. Altough a standard was set, there are still many different values for the frame. Some of these values are Video ( each frame is really 1/29.97 of a second), EBU ( European Buad Usagei at 1/25 of a second ) and Film ( 1/24 of a second ). There are also different divisions of a sub frame. Even though there are many different standards of SMPTE, in Audio today, a frame equals 1/30 th of a second ( thirty frame SMPTE ) as it was wished back in 1967. The musical applications of using the SMPTE standard of timebase all revolve around thirty frame SMPTE. The Roland SBX-80 and the Freindchip SRC are two new SMPTE interface boxes that will soon revolutionize the process of syncing drum machines and/or sequencers to a tape recorder. For those of you who read last months column on “Sync tones and Click Tracks” , this will be an in depth look at the process of using SMPTE instead and along with a sync tone and/or a click track. The Roland SBX-80 ( Sync Box ) is capable of generating thirty frame SMPTE. You print ( stripe ) your multi-track ( 4,8,16,24 track ) with the SMPTE timecode and the SBX-80 will read it from tape and display it hours, minutes, seconds, frames and subframes. These features allow the SBX-80 to act as a SMPTE generator/reader. The real beauty of the SBX-80 is its abilty to record a song. When you record a song, you are a storing the relationship between SMPTE and the tempo of the song ( the clock/sync tone/click track ) from the tape recorder into the memory of the SBX-80. This is accomplished by first recorinding SMPTE timecode at -3 on semi-pro recorders ( where 0 equals -10db ) and at -10 on a pro recorder. Print the SMPTE for at one minute longer than your song. At twenty seconds from where you’ve started printing SMPTE, start printing your clock reference on another audio track of your recorder. For most purposes a ¼ note click in the appropriate tempo is most adecute. After you have striped the ¼ note click on the tape, you are ready to read a song on the SBX-80. The SBX-80 must first be set in “ext SMPTE” mode. Then press record and be sure to start the tape from before where your SMPTE timecode track began. You have the option of having a two bar countin ( where your drum machine and/or sequencer will wait two bars before starting ). The”two bar countin” is a most wise feature and I recomend that it be used for reasons not yet explained. After you have recorded the lengnth of the entire song into the SBX-80, it is then ready to run all your drum machines and/or sequencers. Now here is where the SBX-80 and the SRC start to differ. Up untill this point the theory and the operation of the two units has been the same. Unfortunately the SBX-80 can only generate one assignable clock (1,2,3,4,12,24,48,96, or 120 beats per quarter note ) to its single clock output jack. The SBX-80 can also feed MIDI clock devices and Sync devices via two jacks for each. The SRC on the other hand is much more like a Dr.Click in that it simultaneously outs clock tones and click tracks of many differenet values. The SRC with its optional input module also generates and reads FSK sync tone. Of course the price reflects the features also the Roland SBX-80 list price is $1195.00 and the SRC’s list price is $4995.00 and $995.00 for the optional input module. The stored song can be stored to cassette’s much like drum machine and/or sequencer data. After one has stored this data to cassette the click track can then be erased. The SBX-80 and the SRC need only the SMPTE track as its reference to your song. All of the above mentioned procedure should have been done before any tracks have been recorded. In the case that you are using the SBX-80 after-the-fact, here is the procedure. Print SMPTE starting twenty seconds before the already recorded music. If you have a click track on tape already record it into the SBX-80. If you have no ¼ note click track on tape or the drums were recorded by a “live” drummer, You can tap along with the track. If you have trouble tapping perfectly in time with the drummer, try slowwing the tape down to half speed, and then tap in a ½ note click. Unlike the proceedure with Dr.Click, the SBX-80 looks at every ¼ note of the click track you’ve tapped in. Dr.Click looked at every bar. If you give the SBX-80 a sixteenth note click to look at you would will have four times the resolution of a ¼ note click. You will have to make the SBX-80 output a clock tone ¼ the value that you would have needed. For example, if you wanted to sync up a Linndrum ( requires a 48 clock ) to a live drummer, and you tapped in a 1/16 th note click track, you would have to set the clock out of the SBX-80 to 12 beats per ¼ note. It may sound complicated, but with type of resolution, the drum machine or sequencer can really follow the “feel” of a real drummer. Another ineresting use of the SBX-80 is to make the drum machine and/or sequencer ( device ) start early ahead of the track. If you used the two bar countoff option that we spoke of earlier, you could start the device on the eigth ¼ click instead of the ninth ( when using the two bar countoff the device starts on the ninth ¼ note click ). Then by using the SMPTE offset feature ( this feature allows the device to be delayed ), delay the device untill it isn’t ¼ note early anymore. This feature is useful when using a sequencer/arpeggiator for example in rock for an eight note bass line. In rock, its normal for the bass player to push the drummer for an effect. If had forget to print your inital sync tone before printing your audio, this feature can fix the lag-time when overdubbing a Linndrum to itself. You can also with a MIDI clock device ( Roland’s TR909 or MSQ-700 ) start your multi-track tape recorder from anywhere within the tune and have the device follow the tape knowwing just where in the song to start playing from. With an eight track recorder having this ability means not having to give up tracks for drums and/or sequenced synthesizer tracks. Its like turning an eight track into a sixteen track. You also get the advantage of having first generation drum tracks in the mix. Also on a eight track recorder, alot times the drums are recorded in stereo with no individual separation of each instrument. If you mixer can’t accommidate you, you can use the nmixer internally built into your drum machine.