Secrets of Home Theater and High Fidelity
Volume 1, Number 1, 1994
Section 3. VCRs (Revised June, 2000)
Index for VCRs:
Introduction Super-VHS and Hi-8 Resolution VCR Recording Head Flying Erase Head Fold Down Front Panels Connectors
The first time I can remember noticing that video tape recorders even existed was during a Sunday football game in the early 1970s. The announcer said that they had a new gadget they wanted to demonstrate, and proceeded to show an instant replay by video tape. I purchased my first VCR (Video Cassette Recorder) in 1981. It had three speeds, monophonic sound, and a set of tuners which had to be manually set to the desired stations by turning a small thumbwheel for each tuner. It had a remote control, but I never used it because the controls were also on the front panel of the VCR in very large sized buttons (about 8 buttons). The unit cost more than $1,000 and lasted about 10 years before I had to replace it. Now, VCRs can be purchased for about $500, with high fidelity stereo sound even at the slow speed, numerous features, so numerous in fact, that the remote control is absolutely necessary.
If you go to a home electronics store, you are faced with an entire wall of VCRs to choose from. Most of them are VHS format, with a small number of Super-VHS, Hi-8, and maybe even a digital camcorder. What to do? Fortunately, the technology for VCRs has settled down, and most units are quite reliable, with good quality picture and sound. The tape handling mechanism is complicated, since the tape has to be pulled out of the cassette to be played and recorded on, unlike audio cassettes. VCRs are the most repaired consumer home electronics component there is, due to the problems caused by playing video store rental movies. So, have your VCR cleaned at least once a year, or do it yourself. Like laserdisc players, it boils down to what features you are willing to pay for. Stereophonic sound capability is fundamental, so I would not even look at units with monophonic sound. Thereafter, most of the VCRs have visual search forward and reverse, and still frame. The more sophisticated units have the ability to search at several speeds, move the picture forward frame by frame at several slow speeds (for watching in slow motion), and the freeze frame feature will be steadier on the screen, without visual interference (flickering horizontal white streaks). There may be special digital effects which come in handy if you edit home videos. Check out the remote control for ease of use in operating the VCR's functions.
Super-VHS, Hi-8, and DV
There is also the choice of Super-VHS, Hi-8, abd DV. Regular VHS, which is the standard in VCR recording, has a resolution of 240 lines. This is called the "horizontal resolution" and refers to being able to show 240 VERTICAL lines on a section of the TV screen that is equal in width to the height of the screen (a square). If the subject has more than 240 vertical lines (alternating white and black lines) that would be shown in this square, then the lines would blend together (appearing as gray) and not be distinct as individual lines. This is the essence of resolution, being able to distinguish two objects (lines or dots) as two, instead of their blending together at the edges to appear as one. Standard NTSC live broadcast TV has a horizontal resolution of 330 lines, broadcasts from video tape have about 300, and laserdisc has 420. Super-VHS and Hi-8 also have 420 lines of resolution, although the picture is not quite as good as laserdisc, illustrating that there are more factors than just resolution that go into making a video image.
Note that the previous discussion of NTSC TV exhibiting 483 horizontal lines represents vertical resolution, not horizontal, a fact that has confused many people (including the author). When looking at television specifications, it will say something to the effect that it is "capable of 700 lines of resolution". Again, this refers to horizontal resolution (capability of showing 700 vertical lines). However, since no current signal sources go above 480 lines (DVD) - see discussion of DV below - this resolution specification is only relevant when considering the fact that, the more resolution capability the TV has, the easier it will be for the TV to show a sharp image within the normal 240 - 480 lines of resolution that the various sources have.
A standard VHS tape costs, when purchased in bulk quantities (package of 8 tapes) at one of the discount stores, about $2.50 for a two hour length (called T-120). An extended length tape (called T-160) which works well for movies longer than two hours, costs about $5.00. Super-VHS and Hi-8 tapes cost about $8.00 for the two hour length. (Lower prices can be obtained by mail order.) If you make home videos using the Super-VHS format camcorders or Hi-8 camcorders, then you should purchase a Super-VHS or Hi-8 VCR. Also, for digital satellite systems, if you want to take full advantage of the high resolution on many of their broadcasts, Super-VHS or Hi-8 are the only way to go. Super-VHS VCRs will play standard VHS tapes as well (Hi-8 tapes are about the size of audio cassette tapes), automatically sensing their presence in the machine (most movie rental tapes are in the standard VHS format). If you purchase a Super-VHS or Hi-8 VCR, there will be at least one S-Video output in the back (S-Video carries the chroma and luminance separately, while composite video has them combined). This will be connected either to the S-Video input on your TV or to your surround sound receiver. If you have a laserdisc player as well, then it is important that the TV or surround sound receiver have at least two S-Video inputs.
Although some experimentation has been done using Super-VHS, it is not feasible at present to encode AC-3 (Dolby Digital - DD) onto regular VHS tapes (VHS, Super-VHS, and Hi-8 are analog devices). There are a few D-VHS VCRs available, and they will record digital video, but not HDTV. Digital Video cameras (DV Camcorders) are commonly available, and they have 500 lines of horizontal resolution, although practically speaking, they only resolve about 480. DV VCRs, also having 500 lines of resolution, can be used to play the DV tapes back and to do editing. Blank tape for these are very expensive, so it is not very economical to store movies on them, even if copy protection on DVDs were not enabled.
VCR Recording Head
Flying Erase Head
VCRs work somewhat differently than an analog audio cassette deck used for recording music. The recording head in a VCR (and video cameras) is cylindrical, and tilted at an angle. It spins while the tape moves past it, giving a higher effective recording speed (amount of tape moving past the head per second). The signal is thus recorded at an angle on the tape. The video signal plus stereo sound (with Hi-Fi VCRs) is recorded at this angle. Audio with this type of recording head is very good, even at slow recording speeds. On better machines, the erase head is also on the spinning cylindrical head, sometimes called a flying erase head. This produces sharp breaks when stopping and starting recordings in the middle of the tape. If your VCR does not have this feature, then the beginning of a recording has streaks of color that move up and down for a few seconds. So, flying erase heads are very nice, particularly if you are editing home videos, but also just for recording in general. The problem with the spinning head, present in all VCRs, is that it is very delicate, easily scratched if you are not careful when cleaning the VCR, and is one more moving part in a component filled with such parts. This results in the VCR being the most often repaired component in home electronics.
Fold Down Front Panels
Virtually all VCRs are front loading, as opposed to older units, some of which loaded from the top. You basically slide the tape cassette in, and a mechanism grasps the cassette and pulls it into the machine. On some units, you have to pull open a panel which folds down to expose the cassette loading bay. Often, on the fold down panel are the various buttons for operating the VCR. Even if you use only the remote control for operating the VCR, you still have to fold down the panel each time you load or unload a cassette. With continued opening and closing of this panel, the wiring that connects the panel to the main electronic circuits inside the VCR are flexed, again and again. With time, some of the wires may break or otherwise lose contact. If you prefer one of these VCRs, ask about the repair record on the connections of the fold down control panel.
On the back of the VCR, and sometimes on the front, are the jacks for connecting the VCR to your hi-fi system. Jacks of the front are usually for those who want to copy tapes from their video cameras onto a "family album" master tape, editing the original in the process. The jacks on the back of the VCR are for permanent connections to other components. Some VCRs have one set of inputs and one set of outputs, or two sets of inputs and one set of outputs, or one set of inputs and two sets of outputs. You should determine your particular needs and then make sure that the VCR has the appropriate jacks.
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