Q&A - #14 - June 5, 1997

Q Please help a novice over his head in the hookup arena. I am confused regarding all the "hookups" being bandied about! Please explain what Toslink digital, Coaxial digital, optical, etc all mean. I am in the market for an all-in-one AC-3 receiver (probably Denon AVR 5600) and am trying to figure out which of my existing components I will be able to plug into it without compromising much in the way of sound and video performance.

A Coaxial digital is an electrical connection. Usually, the jack is an RCA type, like the analog audio jacks. The cable is similar to an analog audio coaxial cable, but the impedance is 75 Ohms for digital and 50 Ohms for analog audio. That is why you can't use regular audio cable for digital connections. Toslink is an optical connection. The jack sort of looks like a phone jack, and the cable uses fiber optics to pass the optical digital signal (flashes of light) from one component to another. You need to make sure that whatever type of output(s) you have on the players are matched to the type of inputs on the decoders or receiver. In other words, if your laserdisc player has a Toslink optical digital output for DTS, you will need an optical digital input on the DTS decoder (you would also need a Toslink optical digital input on a DAC if you were using an outboard DAC instead of the DAC in the laserdisc player). Toslink optical connections are nice because they eliminate one more source of ground loop hum.

Q When will DVD technology be available with read/write capability, basically replacing the standard tape VCR and Hard drive technology? Who will be the key players (corporations) that will introduce such a product line?

A The capability is there already, but the issue is copyright protection. It is going to be very handy for computer storage as well as for audio. Key players will be everyone who wants to make a fortune. I just hope the blank DVD media will not be overpriced. In my opinion, that is why Mini-Disc and Digital Cassette Tape Recorders have not really ever been popular. The blank media is too expensive. Blank mini-discs and blank digital cassette tapes should have been a couple of bucks each, at most. Then they would have had a landslide success. About the time recordable DVD becomes available (in a year or two, maybe), we will have download speed (say 1 MB/sec or better) so we can buy our music on the Internet, and store our favorite cuts on a DVD. I'm ready when they are.

Q Regarding your comments last week about direct view being better than projection, I want to say the following. The future of HDTV is projection, and the direct view models can no longer compete with projection. This is with both cost and quality. At the present time, Sony has a 34" HDTV direct view monitor that retails for about $34,000. You can get a Runco 980 Ultra at $24,000 that can go up to 7' wide that will easily outperform the direct view. The Runco can actually go larger but with one projector, 7' will give you the most light output. You would need 2 Runco's to deliver a 10' wide picture. Zenith has a new HDTV projector that retails for around $12,000. It was almost equal in quality to the Runco.

(1) ". . . composite image being formed by three CRTs whose individual images cannot be perfectly aligned with each other . . ."

[>] This was true a few years ago, but with the latest digital convergence systems in TVs, you can align all three guns. A direct view also has to do this same alignment, and it usually requires special magnets. A direct view cannot be touched up like a projector can. When looking at the convergence of most direct views, you will notice that they are off in spots and cannot be easily fixed.

(2) ". . . image passing through lenses, many of which are plastic . . ."

[>] This is true, but the lenses can be filtered (i.e., green and red lenses) to improve color purity. In the pro world there is SMPTE C. This phosphor is expensive and not very bright (low light output). In the consumer world every manufacturer uses a different phosphor, so every TV looks different. With a projector you can use a brighter phosphor, then filter it with a colored lens to give you pure accurate colors.

(3) ". . . image scattering from the projection screen . . ."

[>] This is still a problem that exists, but can be fixed with a custom (after market) screen. The screen is VERY important in reproducing the picture. Screens are rated on their gain. The average screen in a RP set uses around a 5 gain screen. This forces all the light in the center and causes hot spotting. Most screens also have a line structure that gets in the way. Dalite and Stewart offer 0 gain screens that spread the light evenly all around, no hot spotting. They also have no line structure and give you a very clean picture, better color fidelity. The only problem with them is that you lose over half of your light output. You need a dark room for any TV, direct view or projection to get a good picture. You can crank up the contrast on any TV and get lots of light. But TVs do have a range "they" want to operate in. Most sets are overdriven when you pull them out of the box. The new Toshiba TW40F80 comes out of the box with the contrast set at 100 (max, i.e., "torch" mode). But after "properly" setting it up, the contrast is pulled down to around 11, and this is where the set "wants" to be.

Sony's XBR45 series and the older Pioneer line & Pioneer Elite (Pro-x6,x7,x8) are the best projection sets on the market. Toshiba is right behind them. These sets offer more light output, better gray scale tracking, better white field uniformity. You can also tweak selected Sony's and Pioneer's color decoder to give you "studio" accurate decoding. You can forget about the Mitsubishi line. Most are awful.

A It is certainly true that you can get superb projection TV images if you are willing to spend a lot of money. The best video image I have ever seen was from a Vidikron Front Projector, a Snell & Wilcox Interpolator, and a Stewart Screen. But the cost, not including any amps or speakers, was about $80,000. I should have qualified my statements, since I was referring to the mass market rear projection TVs that are in the same price range as the mass market direct view TVs the reader was asking about.

Q I keep getting rumors, not answers to one question... When will DTS be available on DVD? I am in the market for a new receiver, and am not willing to buy into DTS if I can only have it on laserdisc. If they (DTS) are actually going to get into DVD, I think this will be their life line to the consumer home audio market. If DTS doesn't make it to DVD, Dolby Digital is all we will need. I listened to a conversation between a couple in front of a theater the other day. The guy said, "The movie is in DTS and THX at 4:30 and just DTS at 5:00." Her response, "What the #*@& does that mean?!" Now I follow this sort of stuff all the time and know the difference, but that was a litmus test of sorts. DTS trailers are not played in the theaters anymore. If they were, people would have a clue what DTS was, but.... When Joe Average walks into Best Buy and hears DD played off of a DVD, he will ask what sort of equipment he needs to get that sound. An AC-3 receiver will be the answer, and DTS is not even mentioned. If they are going to get into it, they better do it now don't you think??? Or will they end up like super 8?

A At the Hi-Fi 97 show last week, there was an announcement of a DTS DVD that should be out soon. The last people to be sitting on their duff with DTS, is DTS. They are moving as fast as they can, because they know they are sunk if they don't. It is a matter of producing the software and getting it out on the shelves. Since a very powerful director (Steven Spielberg) owns part of DTS, I feel they will be successful in the future. For now, all we can do is wait for the software. Fortunately, it is backward compatible with existing laserdisc players and CD (there are a number of DTS CDs available now) players (connect the digital output of the players to a DTS decoder, and you are in business, as long as you have a set of 5.1 analog inputs in your receiver). Most people (except for Secrets readers, who appear to be a very forward thinking group, from our surveys) probably don't have AC-3 OR DTS yet. To me, the best strategy is to keep your options open. If you buy a receiver, get one with a set of 5.1 inputs, even if it has AC-3 built-in. This way, you will be able to add DTS anytime you want down the road. There are some real bargains in receivers out there right now, because manufacturers are gearing up for receivers with AC-3 already on board. For example, I have seen the Yamaha RX-V2090 for less than $1,000 (normal price around $1,500). Of course, adding outboard processors brings the price up again, but you can add any brand of processor that suits you . . . another option I particularly like. There are a couple of other surround sound technologies on the horizon too, so that set of 5.1 inputs will really come in handy. Dolby was demonstrating AC-3 with higher bit rates (right now, it is 384 kb/sec) at the Hi-Fi 97 show, so they appear to understand the importance of reducing the amount of compression in the audio. I don't have any info yet on the new bit rate, or whether older processors can handle the increased rate. Stay tuned to Secrets. We will give you the news as soon as we have it.

Q I own a Yamaha integrated amplifier and use 12 awg speaker wire that I bought on a tight budget from Radio Shack. I also have all of my components plugged in to a cheapo surge bar. When I power up my amplifier and have the volume set on zero, I can hear a slight hiss coming from my speakers. I have a Bose Wave Radio plugged in the outlet next to the outlet I have my surge bar plugged into and I can hear hiss coming from it also. Could I need a line conditioner, and if I do, what would be a good one to get to suit my needs? I've read your reviews on the Tice and Rotel and have also heard good words about Panamax and Chang (from a commissioned salesperson, though). I would like to spend $200 or less if I need to purchase a conditioner.

Also, I would like to upgrade my VHS VCR to an S-VHS VCR. What would be some recomendations? Also, I know that regular VHS has a 240 horizontal line resolution, and that S-VHS has 420. Will I get better quality from regular store-bought or rented VHS tapes even though they're not S-VHS? As far as televisions, I have a ProScan 27" (model 27113) so I'm sure my TV will handle the better resolution.

A Hiss from the amplifier is normal, even when the volume is turned down. It should not be noticeable from the usual listening position though (it can be heard if you place your ears next to the speakers). This is not something that can be eliminated with an AC power conditioner. Ground loop hum can be reduced with conditioners, in part because you have everything plugged into the same outlet, so the ground potential (voltage) is the same for all the components.

S-VHS VCRs are not very plentiful to choose from. I would go with a Mitsubishi or a Sony. VHS tapes should look the same whether played from a top of the line VHS VCR or an S-VHS VCR. I never have invested in an S-VHS recorder because neither VHS nor S-VHS reproduce the color as well as the original (laserdisc). And now that I am used to laserdisc, AND AC-3, AND DTS, I have not bothered with VCRs at all, except to record a boxing match or football game that I am away from home when they are broadcast. Regular VHS is fine for this. My next VCR will be one that can record HDTV in digital format (I think I will have to wait for quite some time).

Q I have a pair of B&W DM602 speakers with bi-amp capability. I decided to bi-amp the speakers using a ROTEL 6 channel amp RB-956. The amp produces 40wpc and can bridge to 100wpc into 3 channels (Both 8 Ohms). I decided to not bridge the amp and will use 4 channels to bi-amp. Questions: is it ok to use 40 watts for the tweeter and 40 watts for the woofer....? Should I increase the wattage for the woofer? If I should....can you suggest to me the proper wattage....(is 120 watts enough?)

A The B&W DM-602s are really good speakers, and they have relatively high sensitivity (90 dB/w/m). Couple this with their being 8 Ohms nominal, and I think you could bi-amp them just fine with 40 watts each to the tweeter and woofer. However, bi-amping is really most useful when you can control the volume of the tweeter and woofer separately. Since the 602s are 8 Ohm speakers, you may get better overall performance by bridging the amp to get 120 watts for each speaker (bridging reduces the ability to drive low impedance speakers). Try it both ways, crank up the volume, and decide which you like best.

© Copyright 1997 Secrets of Home Theater & High Fidelity
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