Q&A # 218 - February 5, 2001

Staff

Q In your last Q&A, you mentioned something about some new, less expensive, THX Surround EX and DTS-ES receivers. I looked around and could not find anything mentioned on other websites or in stores. Do you know which ones are coming?

A Here is a list of what we know so far: JVC Ultra RX-DP10V - THX EX - $1,500; Adcom GTP-830 Preamp/Processor - THX EX, DTS ES Matrix and Discrete - $1,199; Harman Kardon (Model and Price not available) - THX EX, DTS ES Matrix and Discrete, DTS Neo:6, Pro Logic II, MP3, HDCD; Sherwood R-763 - THX EX, DTS ES Matrix and Discrete, DTS Neo:6, Pro Logic II - $1,200.

Q I have a Yamaha receiver RXV-3000, Klipsch Quintet speakers and Klipsch subwoofer KWS12. I have tried all the different settings in the corner and out of the corner of my living room. I also have tried switching the phase setting. I have all my speakers set to small but the subwoofer still sounds boomy. I am hearing the subwoofer more than I am feeling it. I would like to know if there is a better way of setting it or position it better in my living room. Is it better to get a different subwoofer like the Velodyne CT-150?

A You probably just need to adjust the low-pass crossover frequency of your subwoofer. It is putting out too much in the 80 Hz  - 100 Hz region. Also, try setting the speakers to "Large" and set the subwoofer crossover to about 50 Hz. The volume on the sub may need to come down a bit too

Q I have a HT setup with Jamo 7.6 mains, Jamo 7.2 center, and Jamo 7.3 rears running through a Pioneer Elite VSX33 THX receiver rated down to 6 ohms at 80 watts/channel. The mains are 4 ohm speakers with center and rears at 6 ohms. I also have an older Pioneer VSX 9500 Pro Logic receiver rated at 125watts /channel fronts, 30w/channel center and rear. Could I integrate the 9500 receiver into my system, maybe running my mains for better stereo sound or better HT? I am just not sure whether this is a good thing to do or not. The VSX 9500 is more powerful and is rated down to 4 ohms. Also by integrating this amp, do I destroy the DD and DTS decoding through my VSX33 Elite receiver? If you would integrate the second receiver, how would you set it up? Also, what about a separate power amp. The point I am trying to get at here is more power to my front speakers for cleaner stereo sound.

A This is another question about connecting two preamplifiers together. Even though the 9500 is more powerful, it will be necessary to connect it AFTER the Elite VSX33 in order to maintain your DD and DTS. Connect the mains pre-outs of the Elite to one set of analog inputs on the 9500 and use the 9500 as a power amplifier for your front left/right speakers. Some of our readers have been asking about how to use two receivers for decoding the Surround EX and ES, and in such cases, you connect the rear pre-outs from the first receiver to the inputs of the second receiver, and connect the front left/center/right speaker outs of the second receiver to the rear left/center/right speakers. But, in your case, you want more power to the fronts, so connect it up the way I described in the first part of the paragraph.

Q I have a video/data projector that is mounted on the ceiling approximately 50-75 feet away from the rest of my equipment. I currently have a computer (vga) connector and composite audio/video cable run from the projector. Since the projector is also used for watching DVD video, I was  considering adding an S-Video cable to increase quality. However, I have  heard that S-Video degrades in quality after 15 feet. Would an S-Video cable make  a difference over that long of a run? If so what kind of cable should I buy,  and do I need any additional video amplifiers or other equipment?

A You do not mention the specific model # of your projector, but you do state that it is a data grade. Have you thought about using your PC as your DVD player? You are already running the VGA cable. If your PC is at least a PIII 450, you should be ok. You would just need a DVD-ROM drive and a good software decoder like PowerDVD. You would also need a sound card with an S/PDIF (digital coax) output if you want Dolby Digital.

If you are not interested in using your PC as a DVD player, you should look into a video processor so you can take advantage of your projector. Here is where something like the iScan Plus V2 would come in handy. You can read about the iScan at http://www.dvdo.com and also in our review.

It's true you always want to go with the shortest cables possible, but with that said, you can still go 75'. I would try an S-Video cable from http://www.bettercables.com. They offer good quality cables at a fair price.

Q Can you explain encode, decode, and transcode? I thought encode was only in the manufacturing of the DVD, but I gather that it happens in the player too.

A MPEG encoding happens on the mastering side of DVDs.  Your DVD player has an MPEG decoder that takes the MPEG data and turns it into digital component video and the associated audio streams like DD and  DTS.

The digital video output must then be encoded into a format that your TV can use. So a video encoder in the DVD player takes that digital component video and turns it into analog composite, S-Video, and component. Its confusing, I know! Hopefully, future player/TV integration will have just the digital info going directly from the player to the TV, and analog conversion will happen at the very last second, when it reaches the TV screen. Maybe TV down the road a ways will have it digital even at the TV screen!

Transcoding is the processes of converting one format to another. For example  if you want to convert Pal to NTSC or visa versa, you transcode. If you want  to convert component to RGB or visa versa, you transcode.

Q The grapevine has it that you guys are testing the new Denon DVD-2800 progressive player and that you actually had Denon correct some problems before it goes out for sale. Is this true, and when will your test results be published?

A Yes, Stacey made some suggestions at CES, and this will be incorporated into the release product. We will have one soon for testing, and will publish the results as quickly as possible. It might end up being one of the best values on the market for DVD players ($799).

Q I have a new receiver with that has a set of six input jacks on the back. My VCR only has a set of two. How do I connect my VCR to this new receiver?

A The set of six jacks is for an outboard 5.1 decoder, such as are on some DVD players now. Although you could use the front left/right pre-ins on that 5.1 set for your VCR, don't do that, because it would only come out two-channel stereo. The 5.1 pre-ins bypass all the DSP modes, as well as Pro Logic decoding. So, connect your VCR to a set of two-channel analog inputs, such as CD, VCR, Aux, etc. That way, you can make use of all the various DSP modes your receiver is likely to have.

Q I have read your Essay - "Video Resolution...Simplified" - July, 1999, and I would please like to know the following about video resolution: If I have a high quality standard 525 line NTSC television, what happens when the TV receives VHS, S-VHS, and broadcast signals? More specifically, am I always looking at the same number of lines on a specific TV? If a specific TV always displays about 480 of 525 lines, then does the 240 line VHS signal get interpolated to a higher line resolution, and if so, how is this done and what resolution am I looking at? Does the 400 line S-VHS signal get interpolated to a higher line resolution? And then, what about a broadcast TV signal, is it at a full 525 lines of resolution? Even more specifically, please help me understand how different line resolutions seem to always fill the screen.

A Your television (and mine) ALWAYS paint 525 HORIZONTAL scan lines, stacked one on top of the other, to create the picture. As noted in the essay, of those 525, only 480 are actually picture information. ALL NTSC sources deliver this same 525 (480) horizontal lines. But how many distinct elements of detail make up each of those horizontal lines? That is what changes from source to source in the NTSC world.

Lets work through this together:

When playing VHS, your TV is going to produce 480 horizontal lines to make the picture. But each one of those horizontal lines will have less than 300 unique details left to right. So each element along the horizontal line will be relatively 'fat', at least compared to playing a DVD, for which the TV will still paint 480 horizontal lines to make the picture. But each of those lines will have much finer detail . . . almost 720 unique elements left to right. This left to right detail represents the horizontal resolution, and that is where so many people get confused. There are two resolutions, the horizontal, which is made up of how much detail across the screen left to right, and is described as vertical lines. The 240 line resolution of VHS, the 330 line resolution of over-the-air broadcast NTSC, the 420 line resolution of S-VHS, and 540 of DVD refer to this horizontal resolution (the number is specified as 540 instead of the above mentioned 720, because the specification refers to the number of lines painted in a square defined by the width being the same as the height, rather than the 4:3 frame of the TV screen). The vertical resolution on NTSC is the number of horizontal scanning lines, and is always 525 (only 480 of which are visible, because the rest are lost in the time it takes for the electron beam to return from the bottom right corner of the screen to the top left, to begin another picture).

These different sources and resolutions give the same picture size because:

A) The number of horizontal lines is always the same and
B) The time it takes to draw each of those lines is always the same.

What is different from source to source, is how frequently the signal can change (colors and brightness) while the lines are drawn. Because VHS yields a low bandwidth, the signal changes less frequently, and fewer unique details end up being drawn on each horizontal scan line. But with DVD, there is a lot more bandwidth, so the signal can change rapidly, yielding lots of detail on each line.

I hope that makes it a little clearer for you. If you have any more questions, please don't hesitate to write.

� Copyright 2001 Secrets of Home Theater & High Fidelity
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