Q&A # 55 - March 17, 1998

Staff

Q My system consists of:
Yamaha 2090 receiver, DDP1 AC-3 Decoder
Sunfire Cinema Grand 5 channel amp
Infinity Overture 3 (front), Overture 1 (rear), CC3 (center
Sunfire MKII Sub
Sony S7000 DVD
Pioneer D704 LD
Straight Wire interconnects
Synergistic Research Speaker cable

What would be a good high quality digital preamplifier to go with this system? Are the Infinity speakers a good match for the Sunfire amp? If not, which ones are? How would you grade this system after changes are made?

A It appears to me that you have a terrific system (I'll bring the chips and you supply the beer!) The 2090 is a very good receiver, and you are all set with the 5.1 input jacks if you get a DTS decoder. If you really want to add a dedicated preamplifier, you would need one that has a tape loop or processor loop. Then, you would connect the analog two channel audio outputs from your DVD and LD player to the inputs on the preamplifier, and the preamplifier processor loop or tape loop outputs would go to auxiliary inputs on the receiver. The pre-outs for the front left/right from the receiver go back to the processor or tape loop inputs of the preamplifier, and the outputs of the preamplifier go to the front left/right inputs of the Cinema Grand. The digital output of the DVD player and RF output of the LD player still go to the DDP-1, which feeds the 5.1 inputs of the receiver. This way, you get dedicated preamplification when playing CDs, and dedicate preamplification for the front left/right channels when watching movies. You don't need a digital preamplifier though. You already have digital decoding in the DDP-1 and DACs of the DVD player and LD player. A tube preamplifier will give you some nice variation from the 2090 and smooth out the edgy highs that come from playing CDs in DVD players, or you could stay with solid state. For the latter, there are many choices, while for tubes, there are not as many models with loops. One tube preamplifier I have used for this purpose is the Sound Valves VTP-101i (review published in Secrets, Volume 3, Number 3, 1996).

Q I own an older Yamaha CD player (vintage 1985, 86) that originally cost quite a bit. It used to play almost every CD very well, and I actually liked the sound quality better than my newer CD players (budget class Pioneer). After I moved the unit, I started having trouble with almost all of my CDs skipping. A Yamaha enthusiast I know said there were adjustments for the laser head which need to be reset occasionally, and to remove the front cover to see them. I did just that. There are four adjusting screws near the the drive mechanism and laser head. They are labeled "Tracking Offset", "Tracking Gain", "Focus Offset", and "Balance".  These screws are not in plain view (clearly not meant for the casual audiophile), but I was hoping you could answer these questions:
1. Do I need to fool with these things to get my CD player back?
If yes, then:
2. Do you know what these settings do?
3. How do I go about it? What's the procedure?

A It does seem probable that the laser needs adjustment in your player, but this is definitely not something you should do yourself. It involves much more than just twiddling with the settings. Electronic measurement instruments are needed. The adjustments move the laser head sideways or up and down to make sure it is focused in the track. Take the unit in for professional adjustment. They will also clean the mechanism for you, and you will be much happier with the results than if you played around with the adjustments yourself and managed to get it to work.

Q I would like to know if speaker cables make a differences in an audio system ? If so, what would you recommend for around $250? I have a Bedini class A -amp and a pair of PSB 600s and I am using four master cables for bi-wiring (12 ga). Would you think I could tell the differences in the sound between regular old Monster Cable and $250 speaker cables?

A Speaker cables do make a difference, and the biggest difference is between the ordinary stranded cables and the high performance audio cables. By "regular old", I am assuming you are referring to the entry level stranded cables. For your budget, I would suggest something like Nordost 2-Flat speaker cables. They use Teflon and the conductors are flat. This minimizes inductance and capacitance. Actually, they will probably cost quite a bit less than the $250 you have, but they work so nicely, I can't see recommending spending every penny you have in your budget. You can bi-wire if you want to, but I have never found this to make a difference when using good cables.

Q I'd just like to know the difference between speakers used for hi-fi systems and home theater systems besides the placement and being
magnetically shielded. Is there really any difference in sound quality?

A When home theater was first becoming the big buzz word, and Pro Logic was the only game in town, there was mention of such things as dispersion, bipolar, dipolar, and other things. However, now that we have digital surround technology, with full range sound in all channels, these things are not so applicable. What I generally suggest is that, when possible, get the same speakers for the front left/right as for the rear left/right. This will give you a balanced tonality. If you like the dipolar sound, there is nothing wrong with having them all the way around. Center channel speakers are a separate category because they lay on their side and bass loading occurs from the TV screen. Ironically, the center channel speaker may be the most important, because most of the sound goes there. In my opinion, there is no difference in quality per se, between speakers used for home theater and speakers used for hi-fi audio, because you can use just about any speakers for either purpose. The days of marketing individual speakers as "home theater" are dwindling, and what we see is marketing packages of speakers as home theater systems, but for the most part, you could use the front left/right speakers in those packages for a two channel hi-fi setup.

Q I know it is important to have the same brand for the LCR and surround speakers for home theater, but what is your opinion on the importance of having the same brand of amplifiers all the way around? I have a ML 332 driving the LR and a Citation 5.1 driving the center and surround speakers. Can someone actually "hear" the differences between these amps in this setup?

A Although the differences between the amplifiers in a mass market receiver and high performance outboard power amplifiers are remarkable, the differences between various outboard amplifiers are more subtle. Even so, it would be better to add an outboard amplifier to the rear channels of a receiver, so that the front left/center/right channels of the inboard amplifier would have more power supply to handle them. And, it would be better to have two different brand outboard power amplifiers than to use any of the inboard amplifiers. The most important thing with the outboard amplifiers is to make sure you have sufficient power. Speakers are damaged more often by not having enough power (the amplifiers clip), than having too much power. Remember one of Dr. J's rules for hi-fi enjoyment: "There is no substitute for raw power." There will be much more difference between speakers than between outboard power amplifiers. Good amplifiers are rather neutral in tonality with the differences being in the detail and dynamics.

Q I recently bought a DVD player for my PC. Until I get a real DVD player, I'd like to use it for movie viewing on my television. The decoder card for the drive has a S/PDIF output, and I've ordered a Kenwood 1070VR receiver that claims to have an AC-3 compatible input. My question is, do I plug the S/PDIF output from the card to the AC-3 input on the receiver? If so, will I be getting true Dolby Digital surround sound or am I way off base with this whole issue? I'm not real clear on the AC-3 connection.

A As long as the Kenwood has an S/PDIF input (coax), it should work. If the Kenwood has a Toslink optical input and not the coax input, you would need an adapter such as the one mentioned in last week's Q&A. You will also have to configure your PC software to send out the AC-3 signal.

Q The DVD FAQ by Jim Taylor has the following to say about automatic pan & scan mode:

"For automatic pan & scan mode, the video is unsqueezed to 16:9 and a portion of the image is shown at full height on a 4:3 screen by
following a "center of interest" offset that's encoded in the video stream according to the preferences of the people who transferred the
film to video. The pan & scan "window" is 75% of the full width, which reduces the horizontal pixels from 720 to 540. The pan & scan window can
only travel laterally. This does not duplicate a true pan & scan process in which the window can also travel up and down and zoom in and out. Therefore, many DVD producers choose to put a separate pan & scan version on the disc in addition to the widescreen version."

My question is: Do any DVD titles actually implement this feature? My player (Denon DVD-2000) has a TV setup mode that would appear to select this feature, but I have never been able to get it to work. Whenever I set my DVD player to this TV mode and play a widescreen movie, my TV (4:3) simply shows a letterboxed display, the same as if I set the player to a normal 4:3 TV mode.

A As far as I am aware of, No, the pan & scan feature has not been implemented in DVD movies so far. Currently the option is available but no studio has put the codes into the film. The problem is that directors tend to be picky on how their movies look pan & scan'ed. That is why some movies put the letterbox and P&S versions on the same disc. Just like dual layer, I am sure this will be implemented eventually to save the studios money and encourage more 16x9 films.

Q I sell DSS, and have been selling satellite for the past 9 years. I find DSS picture quality on DSS to be very very good but only on the PPV channels, where I know they use professional 3/4" Beta master original tapes, while other channels are so so. What a lot of people don't know, is that they are picked up from C-Band and converted to Digital at their Castlerock Co. site. My C-band & Ku-band system give me at times much better picture quality over some DSS channels. Do you know which system actually provides or gives better picture quality? And are you aware whether DSS will begin broadcasting in DD and DTV by late summer '98 on some of their channels?  HBO claims it will be broadcasting in DTV late this summer, and the fourth generation of DSS receivers to come this Fall will have AC-3 RF outputs, and I take it DTV outputs too. Have you heard anything on this?

A PPV (Pay per View) channels on DSS are allocated a higher bit rate than the other channels. This allows them to be cleaner overall. C and Ku-band dishes do have a better picture, because they are not compressed to death like the DSS channels are. But DSS is often better than the cable counterpart. However, I have done A/B comparisons with a local network channel compared to that same channel being broadcast over DSS, and sometimes the cable channel actually looks better. There is the slightest delay also, but I prefer DSS to normal
cable. If I had the room for a full sized dish, that would be in my system as well.

When DD is broadcast over DSS, it will most likely not use RF like LD does. It should use a direct digital signal. There are a couple of outputs on DSS receivers, including a low band and high band output. Hopefully, these will be utilized to provide us a link to DD and HDTV. Until mass market HDTV broadcasts are actually here though, we will not know for sure.

� Copyright 1998 Secrets of Home Theater & High Fidelity
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