Q&A # 143 - October 13, 1999

Staff

Q I am about to hook up my Sonotube DIY subwoofer (Shiva 12" driver, 24" diameter, 23" high Sonotube tuned to 19 Hz), and I am going to use a Yamaha 130 watt integrated amp for the power. How do I connect the low frequency channel from my processor to the integrated amp? Do I use the CD input or does it matter? Would it be louder if connected to the phono input?

A First, don't bridge your integrated amplifier unless it is designed to do so. Secondly, I hope your driver is 8 Ohms, because your mass market amplifier will be overdriven if it is 4 Ohms. Third, use the subwoofer output jack from your processor to the integrated amplifier. If it does not have one, you will need to use a crossover in between the processor and the amplifier. You could also just turn the treble control all the way down on the integrated amplifier, but that will not work as well as having a crossover designed to eliminate everything below about 80 Hz. The CD input will work fine, but don't use the phono input, which would be overloaded by the high output from your processor.

Q I was looking into buying the new Onkyo DTR7. I was told that it had cast heat sinks vs. forged heat sinks. Does one type have an advantage over the other?

A For moving parts under physical stress, cast would be better, but for something static like a heat sink, it should make no difference.

Q I'm considering getting a Sony TV for local TV programs, cable/satellite transmissions, and for watching DVD home theater movies. My choice is between the KV-28FX60 Widescreen (16:9) model and the KV-29FX60 Standard (4:3) model. My preference is for the Widescreen. What I need to find out is whether or not I'll have those annoying black bars on the left and right of the screen when viewing local TV programs that are transmitted in 4:3 format. In other words, if the local TV station transmits in standard 4:3 format, can the widescreen model be adjusted to convert this to 16:9 format (i.e., expand the picture to fill the whole screen) as can be done when viewing  DVD movies?

A While I am not familiar with that particular model of Sony 16:9, they all usually offer some sort of stretch or zoom mode. I have had a Pioneer 16:9, Panasonic 16:9, and Toshiba 16:9 and they all had the ability to zoom. The problem is that you can either stretch the image and make everyone look extra wide or you can zoom in and chop off the top and bottom. I find both methods unacceptable and prefer the black/gray bars on the side of the image. You need to decide if you are going to watch more 4:3 material or 16:9 material. If you watch a lot more 4:3, then you might consider the KV-29FX60. Some of the new Sony models offer a squeeze mode on their 4:3s to get the most resolution out of DVD. Personally, I would get used to the bars on the sides. When HDTV kicks into full swing, many moons from now, we are all going to be using 16:9 sets and watch all of the older shows in 4:3 with bars on the sides.

Q I am interested in upgrading my video, with the future (at least as far as I can see) in mind. I am considering the DreamVision DLP projector. A DreamVision sales rep told me that they will have a new HDTV ready model in early 2000, the Movie Star Plus. Specs are 1024 x 768 XGA resolution, single chip DLP, 16.7 million colors, 4:3 and 16:9 Horizontal Frequency 15 kHz - 80 kHz, and brightness of 1100 ANSI lumens. Also I am considering a progressive scan Pioneer Elite DV-08 DVD player (plays DVD audio as well) and HDCD. I also have heard and seen great things from the DVDO iscan. My questions are these: If I get the DVDO, do I not need the progressive scan DVD player (are they both doing the same thing)? Also, is the Dream Vision with those specs truly HDTV ready, or does it suffer from the same issues that CRTs with smaller than 9" guns suffers from, and finally does HDCD really make a difference.

A The DVDO iScan will be best for all non-DVD sources when compared to progressive DVD. A progressive DVD player "should" be able to do a better job. The problem will arise when video material (non-film based material, or improperly flagged film material) is played. Film material is flagged on DVD, and this tells the player how to put together the 24 FPS video using 3:2 pull down. Progressive DVD players use these flags to assemble the display of the film properly. In the beginning, these flags were not always done correctly. Outboard line doublers such as the iScan do not use these flags, and they look at the video material to detect the 3:2 sequence. In some cases they "might" do a better job. In theory, progressive DVD should be the best. Since the resolution of the DLP is 1024 x 768, any signal fed into it will be scaled either up or down to 1024 x 768. DVD is 720 x 480, so it will get scaled up. HDTV has several different resolutions, but the two most common are 1080i (1920 x 1080) and 720p (1280 x 720). Both of these sources will be scaled down to 1024 x 768. So yes, you will lose a lot of resolution. They will still look better than any NTSC, but they will not look as good as they can on a 9" CRT. Also note that 1024 x 768 is a 4:3 aspect ratio, while 1920 x 1080 and 1280 x 720 are 16:9 aspect ratios. In the future we will have 16:9 DLP arrays at much higher resolution. I think we are still a couple of years away though. A PC with a Matrox G400MAX and WinDVD will give you an amazing DVD picture! It can output the exact resolution you need (1024 x 768), and it does an amazing job scaling for the price. We will be covering such products and how our readers might integrate their computer DVD drives into a home theater.

Q I am looking for your advice on making "safe and prudent" upgrades to my current home theater/stereo system which currently consists of a Mitsubishi 45" rear projection TV, Pioneer VSX-900 receiver (about 10 yrs old), Vandersteen tower front speakers, no center speaker (run through TV currently), Velodyne powered subwoofer, Paradigm bookshelf surround speakers, Hughes DSS Direct-TV receiver, Pioneer laserdisc player, Nakamichi cassette deck, and various VHS tape decks. I intend to update to HDTV rear-projection TV when prices and technology mature in the next year or so. The items I am considering for immediate purchase are a Toshiba 3109 DVD player, a Denon AVS-5700 receiver, and a center speaker of some sort. Although I think the specs, features, etc. of the Toshiba and the Denon are what I want, I'm not sure if they will work with the existing equipment and speakers to give me an improvement in my surround sound movie and TV viewing. Do I also need to consider replacing speakers, etc? Also, do you have any recommendation on a center speaker?

A Since you already have two brands of speakers, I certainly would not suggest adding a third. I recommend that you add another set of the Vandersteen towers for the rear, and also get a Vandersteen center, such as their model VCC-1. Paradigm makes fine speakers, but the ones you have are bookshelf size, and I think you would be better off with tower speakers if you are going to be watching DVDs with digital surround sound. Thus, the more economical approach would be to add 2 Vandersteen towers than to get 4 new large Paradigms. 

Q Over the course of a number of calibrations, I got to thinking about the supposed disadvantage of using a digital volume control, namely that some information is lost when volume is manipulated in the digital domain, and a question occurred to me. Is there an analogous disadvantage in adjusting the pre/pro's output very far from its default position of 0.0? If so, one could always calibrate to some other dB level and try to keep the pre/pro gain as close to 0 as possible. What do you think?.

A Digital volume controls work by taking the original digital value and dividing it by a number. This changes the output voltage once it is converted back to analog. The problem in the past was that they were using 16 bits, and too much was getting lost when the number was divided. With the new 24 bit processors, digital volume control might make a comeback. As to the pre/pro issue, the same thing applies, assuming it is digital. For analog preamplifiers, there should be the same amount of loss regardless of the volume, unless you are comparing what happens if you lower the preamplifier volume and increase the volume control on the power amplifier (some power amplifiers have an input volume control), to give the same volume at the speaker. In this case, you could have some loss when the preamp is turned way down and the power amplifier is turned all the way up.

Q I use B&W 805s for the front , B&W HTM for the center, and B&W DM 602s for the rear. I use a McCormack dna-0.5 (100 wpc) for the front and Adcom 5503 (200 wpc) for the center and surround speakers. Would there be any problems with the power mismatch, and if so, would I need another dna-0.5 to bi-amp the 805s? I listen to 2-channel music 90% of the time.

A I see no particular problems, since the McCormack probably has a very sturdy power supply. If you listen to heavy duty action movies, it might be advisable to use the Adcom for the front left/center/right rather than for the rear, but this assumes you like the sound of the Adcom as much as the McCormack. Since you listen to music most of the time, I would estimate you are probably fine as is.

Q Do you know where I can find information on how to build a home sound system with 13 speakers in different rooms?

A Try http://www.russound.com and http://www.nilesaudio.com. Both of these companies specialize in multi-room installations. There are also lots of these kinds of products at http://www.smarthome.com.

� Copyright 1999 Secrets of Home Theater & High Fidelity
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