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Unraveling The Great Quad Debate

Unraveling The Great Quad Debate image
Parent Issue
Day
6
Month
December
Year
1974
OCR Text

What is the deal with quadrophonic sound r Is it just a gimmick being pushed to sell more producís, or is there really art advantage to four channel separation ? What about the battle between Matrix and Discrete? In looking into these and other questions, the SUN discovered that much confusión abounds about quad. With X-mas Hi-Fi buying in full swing, we commissioned an electronics engineer to shed some light on the subject. A real good place to start with quad is about 35 years ago or when the Japanese became an issue in WWti. The Japanese had a curious device capable of scrambling radio signáis in such a manner that only some one with a special receiver could unscramble the transmitted messages. If we replace the terms scramble and unscramble with the new terms encode and decode we have the same machine present today in the 1 )rm of a matrix quad system. The war ended and we forgot about the matrix system, but some wise guy decided one channel was not enough for our hi-fi systems. Everybody thought stereo was, bluntly, dumb! Without thinking we tried to throw legs in the path of development with such questions as, "'How are you going to broadcast stereo? How are you going to get a reasonable amount of playing time on a record and TWO channels? Where am I going to get the money for a second amplifier, another speaker and who wants to buy my mono tape recorder?" I'm sure any of you could answer all of these questions now. At least you could answer with "It's obviously better!" If you are under 50 you miglit not still hold a grudge against the wise guy who decided two channels are better than one. The same wise guy was definitely smart enough not to try the same trick twice. So we have a new wise guy who's trying to teil us that four channels are better than two. And we have a whole new batch of legs to toss in the way , replacing the word stereo with the new word ... quad in each of the above questions. Quad is better, but only if you're willing or able to afford it. ORIGINS OF QUAD As far as the recording industry is concerned four channel has always been around as well as 8 and 16 channel. Thank God they're not trying to press that on us! The industry has been using all those channels and more to make the types of STEREO records we're used to. What they do is attach a microphone or a cable to anything in the studio that moves and record it. The fun part comes when the engineer (butcher) comes along and decides which and how much of all those channels are going to be heard on your sound system. With all due respect to the recording eers this process requires a terrific amount of skill. A good engineer can make a poor group sound better and a good group sound worse. To the engineer two channel or four channel doesn't make that much difference. Actually, four channel gives the engineer more room in which to work with more imagination. The problem comes in trying to put four channels of information into the two sided groove of the record. Obviously, the left and right channels of stereo go on the left and right walls of the groove. What is the best way to put four channel information on two walls of a record groove? - In 1969 the first four channel systems were introduced to the public. Basically, these systems derived four channel sound by enhancing existing stereo records. This meant that the rear channel music was only very slightly different from the front music. What the public wanted was music that sounded as different front to rear as it did left to right, henee, front to rear separation. The industry was torced to give us a dramatic increase in front to rear separation in order to continue to gain acceptance with four channel. This didn't pose too much of a pro problem if you were willing to invest in a four channel 8 track or reel to reel tape deck as well as two more speakers and two more amplifiers. Prerecorded 8-track tapes are expensive and prerecorded reel to reel's are even more so. And to the real sound buff (audiophile), these tapes were usually not very good sounding for various reasons. The best way to get four channel sound, then, is through records. ffTn mttf MWMiMiíTli i- a mi i-rim mu n n mi nw ■■ ■■■■ That also poses the best question; how do you get four channels onto two walls. With tapes you simply narrow down the existing two channels and add two more. MATRIX EMERGES The Japanese being as conservative as they are, brilliantly remembered a discarded 'piece of equipment which they immediately dusted off and dragged into their neat little laboratory. They had to drag it because it weighed about three hundred pounds and was about three feet tall. This was their original WWII secret code box. Remember the device capable of scrambling radio messages. The only trouble was they had to make their secret code box the size of a secret code ring. Of course this was no real problem either since they fully realized the advantages of some new devices called transistors and integrated circuits. They had other technical innovations, such as OCL'and PI 1 IC and even FET's. These are the technical jargon of secret code ring and wrist TV manufacturers. Anyway they managed to get the four channel music scrambled onto the record and a descrambler into your four channel amplifier. This was the first matrix decoder. They called it that because no one wants to listen to scrambled records through their descrambler, but everyone wants to listen to their encoded records through their matrix decoder. Definitively, a matrix is an ordered array of numbers. In this case the front and rear channel info is orderly arrayed onto the disc by the encoder and when the decoder hears this it puts it back into its four channel form and transmits that to each of the separate speakers ENTER "DISCRETE" Somebody decided that matrix quad was not good enough and that another system was far superior to the matrix system. RCA and a Japanese company got together and decided to cali themselves the Japanese Victor Corp. or JVC. They say the matrix system is less than effective because the decoder doesn't know the difference between a four and a four (that's not a misprint) i.e. a 3 plus 1 four is different from a 2 plus 2 four and even a 1 plus 3 four. Let me give you a picture of what these numbers indícate. Let's say in this case the four indicates a four piece band, i.e. keyboard, drums, lead guitar, bass guitar. Let's say the engineer wants a 2 + 2 format in the rear channels. This could be the two guitars on one side and the keyboard and drums on the other side, thus 2 + 2. Half-way through the song, the engineer may decide to leave the keyboard man by himself on one side and bring in the other three on the other channel, henee 1 + 3. Then he decides to switch them or do a reverse. Now we have a 3 + 1 . What me mamx aoes ís give a comoinauon ui au me: additions of four which means that you can't nat t Vio doci rori norfoct oori rn twin gei me uesireu peneci separauun. JVC says that modulation is better than encoding. Modulation means that they put an inaudible sound at the bottom of the groove as well as the total four channel should on the walls of the groove. What that inaudible sound at the tom ot the groove does is carry the difference of the front and rear channels. In simplified form it tells each of the fours on the walls of the groove exactly what kind of four it is, i.e. a 3 + 1 four or a 2 + 2 four or a 1 + 3 four. This gives a very obvious improved front to rear separation and distinction and was therefore tenned discrete quad. Let's go through it once more and make sure you understand this exactly. You're a matrix decoder and fhe music you receive behaves like the number four. Immediately your decoder has to determine what numbers addeü together make tour and A,'hich of those numbers w go in the front or i m w rear speakers: You decode, 3 in front and 1 in back; or, 2 in front and 2 in back; or, 1 in front and 3 in back. You can see you have a one in three chance of getting it exactly right. You don't have enough information here to teil you which of the music is supposed to be in the front or the rear. What this means is that quite a bit of the music that's supposed to be in one part of the room will end up in a different part. If you're standing in the middle of a quad system a given instrument will sound primarily in one corner, but quite a bit of that instrument will bleed through to the rest of the room and cause somewhat of a sense of misdirection. To a lot of us this wouldn't make much difference, and actually a little bleeding is necessary to give a feeling of presence. Too much bleeding is confusing. Now you're a discrete demodulator and you're given the musical information in the form of a four again. This time, however, the walls of the groove of the record say four, but the bottom of the groove, i.e., the modulated portion says 1 . That means 1 is in front; what 's in back? You're demodulator thinks 4 minus 1 equals 3. Aha! Three's in back. Now the modulated portion says 2. No sweat, 2 in front and 2 in back. The modulated portion says 3. You know now that 3 goes in front and 1 goes in back. You've eliminated the 1 in 3 possibility of getting it right. Now each instrument comes from wherever it's supposed to with the correct amount of bleeding. Armed with this information you know more than 90% of the audio salespeople know about quad. Try it. Go to any audio store and ask a salesperson what the difference is between discrete discs and matrix discs. You'U never have had so much fun in your life. WHICH SYSTEM IS BETTER? You're next question is, "What's all the confusión about?" From what ï've just told you, it's obvious that discrete is the best way to go. This would be true if descrete didn't develop some problems of its own. First, the modulation used up more record space and your LP became an SP. Then they found out some of the higher frequency notes didn't come through too well. Also you were told you had to buy a new more expensive needie that would be capable of that ultra high frequency modulation. Then the discrete demodulator had to be tuned to whatever needie you bought. Finally after you had everything all set up and you were ready to listen to some fine discrete quad sounds, you found that records had a tremendous degree of quality. Some records would put the piano in one corner, place the bass in another, the horns in another, and the tympani in the last corner. Great! But other records would get maybe two or three corners right but the remaining corners would go fzz spsst zap pop etc. No one wants to listen to a recording of Rice Krispies backed up with a rio and horn section. The originators of matrix decoding made everyone aware of this and claimed superiority. Discrete modulator manuracturers came out with improved demodulators and cheaper needies. RCA held up their end with improved records. Decoder manuracturers decided they had a fight on their hands and came out with improved decoders claiming ter separation. Everyone had their own ideas and between 1971 and 1974 the consumer was bombarded with SQ, QS, Vario Matirx, Regular Matirx, SQ logic, SQ full logic and Vari Matrix from the decoder manufacturers and CD-4, s Quadra-disc and Discrete from the demodulator manufacturers. To make things worse compact manufacturers came up with quatra-sound, quadra-play, quadaptors and other quad sounding paraphernalia that has no more te do with true quad than Evel Knievel jumping a canyon on a motorcycle. No wonder we were all confused! DISCRETEMATRIX 1974 The manufacturers seem to be getting it together. Most quad units can now be purchasedwith both a demodulator and a decoder built-in that work. Decoded FM is quickly becoming available also. Detroit was one of the last metropolitan áreas to introduce FM matrix quad. Soon there may be a discrete FM quad method of broadcasting. (There is some controversy concerning the quality of quad broadcasting on two Detroit stations in particular. Look to a future SUN for a report on the various claims being made.) The question now if you want to go quad is-what equipment to buy. If you're looking into the possibility of a sound system you will first have to determine how inuch you can spend. This is when you will decide if you can afford a quad system. A reasonable one can be had starting around $500. [f you need to spend less than that, I would consider a good stereo system capable of being adapted to quad as your intórests increase in the future. Good stereo is better than cheap quad. When you do find yourself in the quad category, be very careful in your selection. Some good name-brands to look into are: Technichs; Sansui; Pioneer; Harnian Kardon. All these brands have both matrix and discrete quad built right into the unit. Technics is a good unit to look into if you're hovering right around the S500 mark. If you're looking a little higher the other three brands offer exceptionally good value. The Pioneer QX-949, for example, is an extremely well accepted unit. However, that receiver combined with speakers and a turntable will bump you over the SI 000 mark. What you can do with this unit is set it up as a stereo system with only two speakers and have enjoyable sound until you're able to purchase two more speakers. At that_ time you would simply flip a switch on the back of the '" QX-949 and away you go with a whole new quad system. The same goes for the Harman Kardon and the Sansui units. You may think there's no difference so why worry what kind of unit you get. The trick here is to shop the shop. Find a dealer that you trust and stick with him or her. Teil the salesperson what you want to do and how much you want to spend. Make sure your dealer has a good return policy and they're willing to help you even after you've given them your money. A good policy is to get the dealer to come out and hook up your unit for you. That way if there are any problems they can be solved for you on the spot. Unless you're an expert in electronics, no one knows more about the individual components and how they hook up than your dealer. You won 't be surprised at how agreeable a salesperson is before you hand over your moeny; so get the store to agree to deliver the equipment and hook it up for you before you pass the bread. This will not only aid you initially, but in the future the salesperson will be totally familiar with your system and will know exactly what when you give the store a cali concerning a problem. So now you have some idea of just what quad is about. If you don't dweil too much on the small stuff you won't be confused. Make sure that you understand exactly what you're getting into and doublé check with your salesperson on the details. If you have any doubts concerning quad or any of the aspects have the store supply it in writing. If you have any questions at all concerning quad or any aspect of sound equipment, write a letter to the SUN. Cive us a tough question or one that everyone seems to have and maybe we'll print it with an answer . Thanks for your time. What is the best way to put four channel information on two walls of a record groove? Currently the Discrete (RCA) and Matrix (CBS, Sansui) systems are battling it out for mass acceptance. Through quad s early development a variety of systems were introduced and then abandoned, leaving the consumer holding the bag. Now it appears the manufacturers are getting it together . . .