Q&A # 109 - March 30, 1999

Staff

Q I hope this helps the individual who is having the "hiss" problem with his Velodyne FSR-18 subwoofer. I am currently looking at purchasing the new Velodyne HGS-18 or HGS-15 and have been speaking to officials at Velodyne. They have told me that some of the old FSR-18s (produced just before being replaced by the HGS-18) and the first made HGS-18s have this same hiss problem and that for most people it is not noticable. However, models of the new HGS-18 produced (and HGS-15 as well I believe) since approximately March 17, 1999 (apparently these subs are dated on the back - great idea!) have eliminated this hiss. Furthermore, I am very delighted to say that I was told that if someone recently purchased the HGS-18 or FSR-18 that the company would change the component (I believe at no charge) so that the hiss would be eliminated!

A Thanks for the information.

Q I have a VCR that is almost three years old and has been used practically everyday for recording TV programs. Will a recording and playback average of about one hour everyday for three years constitute heavy usage and damage the heads beyond repair? For the past two months, playback from my VCR has been horrible. I've used one of those dry type head cleaners, and it only helped a little. I dare not use it too much because the instructions say not to use it consecutively for a certain number of times or it might scratch the VCR head but then again the heads might already be worn out. Besides, the model (Toshiba) I have says it is self-cleaning (and auto tracking) as it is. Can there be any other cause for the poor video or is it time to buy a new one? If I use the VCR as a TV tuner (using line inputs and outputs) there is no problem with the video so I'm sure it has something to do with the heads. If I do have to buy a new one will a "Titanium coated" (as advertised) head VCR last longer? I not familiar with VCR innards so I might as well also ask, "Are the recording and playbacks heads the same or separate?". If separate then does a VCR that is advertised as having "Titanium coated heads" have all the heads Titanium coated? I seldom use the VCR for rented movies (LD and DVD is sooooo much better).

A I think your VCR heads are simply out of alignment. Modern heads and tape are so good, it is unlikely that your heads are worn out. But after that much use, the alignment can shift. You should take your VCR in to have it thoroughly cleaned and aligned once a year even if you didn't use it as much as you have. Unless your VCR is one of the economy models, it likely has a "Flying Erase Head" which means the erase head is on the rotating drum along with the recording and playback heads. Recording and playback heads are always on the rotating head. It is only the erase head that is stationary on some low priced VCRs. Titanium coated heads might last longer, but they all last a long time these days. Select your next VCR based on the features, such as how well it performs in freeze-frame, and having an easy to use remote control. Don't worry about the heads. Also, DVD and LD are more than just better, image wise. Rental tapes are very bad for VCRs because many renters abuse the tapes, and damaged tapes can leave metal oxides inside your VCR as well as speed up the process of throwing the mechanism out of alignment. I have a high quality VCR here in the lab, and if I were going to watch rental tapes, I would purchase another VCR just for that purpose. It would be one of the very inexpensive playback-only VCRs that can be purchased for about $100. I would use the high quality VCR only with tapes I have recorded myself, such as home video archiving.

Q I have a question regarding TV screen resolution. I've read that VCR tapes have approximately 240 lines of resolution, broadcast cable about 330, LDs 420, and DVDs 480. I assume that these values are for a specified distance on the screen (i.e., 240 lines per 12 inches or soemething)? Otherwise, if these values were for the number of lines of resolution for the entire screen, wouldn't a 20 inch TV have a better picture than a 35 inch TV (240 lines across a 20 inch screen would look sharper than 240 lines across a 35 inch screen). Yet if this number is not for a specified distance, it would seem to me that bigger screens would have to extrapolate the data to come up with something to fill in the rest of the lines with. I compare this to a computer monitor with a 640x480 pixel image being displayed. If you magnify the image to say 2x or 3x, you lose a lot of the picture quality.

So, can you explain resolution and how it relates to different size TV screens? Also, one of my TVs, which is a few years old now, is a 'monitor' TV. What exactly does 'monitor' mean?

A Resolution is a specification. It remains the same number regardless of the screen size and how far away you are sitting. For NTSC TV, the vertical resolution is the number of horizontal lines, and it is always 525. However, some of those lines are missing because of the time it takes for the electron beam to go from the right bottom corner back to the top left so that it can begin the next scan. So, the actual number of horizontal lines visible is 480. That number does not change regardless of the source, be it broadcast TV, VHS-VCR, DVD, or whatever. The horizontal resolution is the maximum number of vertical lines (alternating black and white lines next to each other) that can be displayed without the alternating lines merging into gray (in other words, keeping them distinctly black and white lines). Today's TVs are capable of resolving far more vertical lines than the sources can produce, so the final horizontal resolution just depends on the source (the numbers you listed in your question).

For TVs, the horizontal resolution is given in terms of a square, rather than the rectangle shape of TVs. So, the 480 line horizontal resolution of DVDs means that 480 lines can be displayed in a square defined by the height of the TV picture and the same distance wide as the height. Remember that TV size is given as the diagonal, so you have to measure the height and width to get the proper numbers. For a 32" TV, the height is about 21.5" and the width 29" (this is why they are called 32" TVs, because the number looks better for marketing purposes). There are 480 horizontal scanning lines displayed (the vertical resolution) in the 21.5" of image height, and there can be a maximum of 480 vertical lines (the horizontal resolution) displayed across 21.5" of image width. As a result, you could say this is a 480 x 480 image. For computer monitors, they specify the resolution across the entire picture tube rather than a square. Instead of 480 x 480, they would call it 640 x 480 (width x height). For HDTV, the specification is, like computer monitors, specified all the way across the image, but the height is first, followed by width. The highest resolution is 1,080 x 1,920 (height x width). HDTVs are 16:9 aspect ratio, while NTSC TVs are 4:3 (ratio of width to height).

The word "monitor" usually refers to a TV that is used for viewing signals coming direct from a TV camera, such as in a television studio. It could also be used to frame the image when taking home videos. The viewfinders in camcorders are "monitors". They don't usually have TV tuners inside, but it is really the purpose you are using it for, rather than the TV itself. Sometimes monitors have higher quality image capability than regular TVs, but not necessarily.

Q In a previous Q & A, you mentioned that a tube 2 channel preamp may be connected to the receiver if the receiver has main-ins/pre-ins. Problem is my receiver doesn't have these. Would it be safe to connect the output of the preamp directly to the CD input of the receiver?

A Yes it would be safe. However, you will be going through two preamplifiers, so it will be necessary to be very careful with the volume controls on the tube preamplifier and the receiver. To start out, set them both all the way down, put in a CD, and press play. Then turn the tube preamp volume up just a notch. Then turn up the receiver volume control until you barely hear the music. Now, back to the tube preamp and then back to the receiver. You can easily overload the input of the receiver, so just go slowly and you won't have any problems. The chances are you will end up with a situation where the receiver volume control is set about 1/4 of the way up, and you will be fine tuning the volume with the tube preamplifier. The tube preamplifier may be capable of about 10 Volts of output, while the CD input on your receiver could go into distortion if more than about 3 Volts is input to it.

Q Which kind of subwoofer connection should I use with smaller speakers like mine (with one OR two subs)? Everyone and their brother seems to wholeheartedly recommend the line level connection even though these speakers may drop off a bit before reaching the crossover frequency. My instruction manual recommends the speaker level, and that would seem to make more sense to me. But I've experimented both ways and don't really have a preference either way. Can you explain in plain English why the line level connection is usually preferred even in a borderline situation such as mine? My receiver does still re-route the LFE to mains, so that shouldn't be an issue.

A A line level connection to the subwoofer is usually preferred because the speaker level output has to be downconverted to a lower voltage before it is sent to the subwoofer's amplifier. Secondly, the speaker cable going to the subwoofer with high level input is unshielded, while line level interconnect is shielded. Lastly, the speaker level connection usually has a fixed crossover frequency sending the high pass back to your satellite speakers. The fixed frequency may not be optimal for your speakers. But the bottom line as always is whether or not you are happy with the setup. If you are, by all means, use the speaker level connection. You will save low frequency energy from bothering your satellite speakers, but there will be no savings in amplifier power. The low frequency power that would have gone to the satellite speakers is absorbed by the high pass crossover network in the subwoofer.

Q How far can I run an S-Video cable before the signal degrades to be no better than the RF output of a DSS receiver?

A This depends on the quality of the S-Video cable. I have used 25 foot runs of Monster with no problems. You should be able to go 100 feet without any serious loss. I believe it would take even more before the picture would look worse than from the RF. S-Video will always be better than RF because S-Video has the Chrominance and Luminance signals separate, plus the RF has to go through demodulation.

Q I bought a Toshiba TW40F80 Television. I have been through Video Essentials to start tuning it and have a question. How long should the TV burn in before having it adjusted?

A The Toshiba straight out of the box is very blue, even in the low color temperature settings. I would adjust the front panel controls, color, tint, sharpness, brightness, and contrast now. Let the set run for a couple of months. This will allow your set to break in, then spend the money to have an ISF tech come out and touch it up by tweaking the convergence and gray scale. Make sure the ISF tech is using a color analyzer.

Q I currently own a Classé CDP.5 CD player but really want to get into the DVD side of things. My question is, has the CD performance of the DVP-S7000 been downgraded in its new form? Or more importantly, is the performance of the DVP-S7000 any good as a CD player? I should be able to nearly swap the Classé for either Sony player, but since it will double as my audio solution, I thought you might be in a position to save me some time in the critical listening department. The Classé has a real smooth presentation that I like in comparison to my previous player, a Marantz CC65. That player was bright and forward, not ideal by any means.

A I would suggest keeping your Classé CD player and adding the Sony DVD S-7700 as a DVD player. The Sony DVD player is one of the best sounding DVD players used with CDs, but it is not as good as your Classé. The differences are subtle, but if you want to get the very best from your CDs, stick with the Classé. If you want to just have one box, the 7700 will suffice.

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