Q&A # 139 - September 20, 1999

Staff

Q In your film reviews does "filmed spherically" mean that the film is anamorphic on the DVD?

A No, it means that the film was originally shot (in the camera) using a standard lens rather than an anamorphic lens. Such films may be transferred anamorphically to the release print shown in the theaters, while not transferred anamorphically to DVD, or it can be anamorphic on the DVD for use with 16:9 TVs. Films shot anamorphically (in the camera) are transferred to anamorphic release prints, but are not necessarily anamorphic DVDs for use with 16:9 TVs. See the Primer (Volume 1, # 1) in the TV section for a complete explanation. (We update the primer every year.)

Q I own a Yamaha RX-V590 receiver with several ambient sound fields in its signal processor. Recently I connected to Sky Satellite digital TV. In the output (RCA) terminals of the satellite decoder, I used a "Y" splitter so one signal goes directly to the receiver (Laserdisc Input) so that I can record from the music channels without having the VCR on. The other pair from the "Y" goes to my Sony HiFi VCR, latest model, audio input, and the VCR's output goes into the VCR1 input of the receiver. The problem is that when I use the laserdisc path, movies sound in great Dolby Pro Logic, but when I connect to the VCR1 path, the sound goes down in volume, and the Pro Logic effect is completely lost (the center channel sounds loud and the mains are "sucked in"). So, If I watch a movie "live", I have to use the laserdisc connection in order to get good sound, but if I record it in the VCR, the sound is lousy. On the other hand, if I play commercial videos on the VCR, the sound is great in the VCR path. Why is the pro Logic signal "scrambled" when passes through the VCR on its way to the receiver?

A Somewhere along the line, your signal is being converted to mono. The sucked in mains are probably just the leftovers of whatever is extracted from the mono signal in the left and right audio channels being fed to the receiver from the VCR. Since commercial stereo tapes played on your VCR through the receiver are in stereo, the mono conversion is happening during the recording process. It may be a problem in the menu settings or one of the pushbutton controls in the panel on the VCR. There are so many controls on hi-fi components these days, it would be easy to have one of the controls on the wrong setting, so check all controls to make sure the record mode has been set to stereo for the audio.

Q How many electronic components should be plugged into a single outlet (with an adapter and surge suppressor) safely? Is there any specific type of surge suppressor that you would recommend? Are computer type surge suppressors worth it for A/V equipment? In a recent storm with high winds, I lost electricity. I heard a loud pop but initially didn't realize what happened. A day later, I noticed that the outlet that I had all my A/V equipment plugged into was black and that the circuit breaker for that room had tripped. None of my equipment was turned on but was plugged in. The normal outlet had two receptacles. I had purchased a 6 receptacle adapter with surge suppressor so that I could plug in all my equipment:

1. 36" TV

2. VCR

3. DVD player

4. CD changer

5. Receiver (5 channel--100 watts ea, 2 channels-25 watts ea)

6. 125 watt Powered Subwoofer

The surge suppressor/adapter was one of the inexpensive ones (<$20) that was "rated for audio/video electronic equipment". It became fried and was unusable after the event. With all the black soot around the receptacle, I feel lucky that I didn't have a fire. Is there a way to calculate what would be an acceptable electrical load, say from the watts from each piece of equipment?

A Your $20 surge suppressor did its job and saved your equipment. Otherwise, it might have been your hi-fi stuff that got fried. Computer surge suppressors do the same thing that ones specifically made for hi-fi do, with a couple of exceptions. They all contain small diodes that break the circuit within a very small fraction of a second when there is a surge in voltage. They contain other items to help remove radio frequency noise as well, since computers and hi-fi equipment all do not like RF. The hi-fi units are usually called AC line conditioners or Power Line Conditioners rather than surge protectors. I have used both the computer type and specific hi-fi units with success. Both are rated usually to around 1,500 - 2,000 watts, and both should work fine with your system. However, the one that I like particularly is the Rotel RLC-900 Power Line Conditioner ($200 USA), which is made for hi-fi. It has a delayed turn on feature for power amplifiers, and will let you turn on your entire system by turning on just the receiver.

Q I have a Yamaha RX-V2095 receiver and want to use my Onkyo EQ Integra series, so can you recommend the right connection?

A If you want to use an EQ with a receiver, you need to have pre-outs and pre-ins that can work together. For receivers with pre-ins, usually only the mains have the pre-outs and pre-ins (called main-ins) arranged so you can route the pre-outs back to the main-ins without causing oscillation. You will find two U-shaped pins that connect the pre-outs and main-ins on the back of the receiver. Pull these out and store them safely somewhere. Then, connect the pre-outs for the front left/right to the inputs on your EQ, and the outputs of the EQ back to the main-ins for the front left/right. This will let you use the EQ in all receiver modes. You can't do this with the center or rear surrounds on most receivers. The only way to use a five-channel EQ is with a surround sound preamplifier/processor and a separate five-channel power amplifier.

Q I have noticed that when my AV tuner (Onkyo TX-DS747) is set to any of the surround modes (mainly hall, arena, stadium and live type surround settings), there seems to be a noticeable quiescent hiss coming from the left and right front speakers. When I set the surround to off (i.e., stereo mode), the hiss is virtually not there. Is this a problem or is it normal ?

A This is pretty typical with mass market processors, and even in some high-performance processors. Once the signal has to go through more chips, hiss becomes noticeable. It is a fundamental electronic noise that eventually builds up to audible levels as the signal passes through more and more circuits.

Q I'm planning to connect a RX-V595 (as decoder and amp for surround speakers) and Rotel RB-991 as power amplifier for the main speakers through main speaker pre-outs on the 595. Please, feel free to throw suggestions, if any.

A The Yamaha RX-V595 does not have pre-outs. It only has pre-ins, so you cannot connect an outboard power amplifier that way. However, if your outboard power amplifier has volume controls, then you could use the recorder output jacks on the Yamaha and adjust the volume for your front left/right speakers that way.

Q Can you explain these new 96 kHz/24 bit DVDs, DVD players, Receivers, etc.?  From my understanding, when a digital output on one of the new DVD players is used, the signal is downconverts to 48 kHz/20 bit. Do any of the new DVD players send a 96 kHz/24 bit digital signal? Now, if the analog outputs of the DVD player are used, does the preamp, receiver, etc. need to be 96 kHz/24 bit ready or is that strictly regarding the digital inputs? I own the Denon AVP8000DTS preamp/processor (which has no 96 kHz/24 bit stamp on it), so I was wondering what I was listening to when I switch between the digital and analog outputs of the DVD player.

A Most of the DVD players from last year that have 96/24 DACs downconvert 96/24 digital bitstreams to 48/20 digital bitstreams. However, they do use the full 96/24 in converting the data to analog audio, so if you use the analog outputs from the DVD player to the receiver, you will get the full benefit. Some of the DVD players coming out now do have 96/24 digital outputs, and many of the new receivers have 96/24 decoding, but you need both the player and the receiver to take advantage of this. Unless your process says that it will process 96/24 in the instruction manual, it is doubtful that it would handle it. I suspect you are getting the better signal by using the analog connections from your DVD player to your receiver. Using the digital connection is likely giving you downconverted 48/20 that is sent to your receiver for decoding. Keep in mind that having a separate transport and DAC is not necessarily going to give you better sound. Sometimes it can be worse. There are plenty of excellent CD and DVD players out there that have the transport and DAC all in one box. The only downside is having to use several cables between the player and the preamplifier.

Q I have a Yamaha DSP A-1 as my Pre/pro and an external THX six channel power amp. I have Yamaha's DVD Changer (C900). What can I say, they look great together in the Champagne finish. It replaced a Sony S5000 DVD player. The Sony was nice, but no 96/24 and no DTS output. The question is where is the better DAC? In the 2nd generation non-DTS SONY? In the 3rd generation Yamaha 96/24 DTS DVD player or the DSP A-1?

A I put this and the preceding questions next to each other so you can see how many people are having difficulty with the 96/24 issue. Here, again, the player may or may not output 96/24 through the digital connection. You will need to look at the instruction manual to see if it is downconverted to 48/20 at the digital output. Even if it is not downconverted though, the DSP-A1 does not decode 96/24, at least this is so for the initial versions. So, your best bet is to use the analog outputs from your DVD player to the analog inputs on the DSP-A1. When DVD Audio takes hold (players and software availalble), you will be able to use the 5.1 analog inputs on the DSP-A1 connected to the 5.1 analog outputs on the DVD Audio player. Again, it is not always necessary to use DACs outside of the player to get good sound.

� Copyright 1999 Secrets of Home Theater & High Fidelity
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