Q&A # 238 - July 24, 2001

Staff

Q I was just wondering what kind of speaker set up you would recommend for my hometheater system. I am planning to purchase an Onkyo DS575X receiver but have no idea what speakers to use with it. My friends recommend using the Definitive Pro Cinema 80 speaker system. However, I would like to hear from you, the experts.

A You should select your speakers among those with 8 Ohm nominal impedance, and 91 dB/w/m (or higher) sensitivity. There are lots of speakers like this to choose from. Just go to the store and have a listen to all those that fit the specifications I described, and choose the ones you like best.

Q I'm undecided on DVD-A and Super CD.  Should I wait? I'm a huge fan of Jazz, so I caught someone's review of Miles' Kind of Blue master tracks being in the new high sampling of the SACD, and it greatly intrigued me. But that's SACD, and there doesn't seem to be much of anything on DVD-A. Will SACD be dropped because of Sony/Philips trying to cash in on their patent, and DVD-Audio become a greater standard? I only mention this because I have been burned by the VHS/BetaCam debate at the beginning of home video. Sony did introduce a lower priced Prog DVD w/o SACD, and you guys mention it, but I have not seen a review. I'm fairly certain it still has the chroma problem that the 9000 had, but it is possible they went the 7000 way, with their own MPEG chipset. So is it better to hold out the money and not go the SACD way, or just get it?

A Although there are a number of DVD players that have DVD-A analog output, SACD is on separate players, at least for now. Fortunately, there are some really inexpensive players coming out shortly, in the $300 range, so I would suggest getting a DVD/DVD-A player and a SACD player that is multi-channel capable. The only problem then is that you will have two sets of 5.1 analog cables to worry about connecting to your receiver's single set of 5.1 analog inputs.

Q I have a Dolby Digital and DTS AV receiver which has no "Circle Surround" or other options for listening to music (radio, CDs) or cable TV from all speakers (main + surround), other than Dolby Pro-Logic. The 5.1 digital sound is great from DVD sources, but listening to music in Dolby Pro Logic is less than desirable.

My receiver has speaker A & B options. I have BIC Venturi DV-62s as mains, DV-52s as my surrounds, and a DV-62CLR center channel speaker. I also have a Kenwood powered subwoofer. Can I connect my surround speakers to both my A & B speaker connects (presumably via splicing) in order to listen to the radio or CDs from both my front L&R speakers as well as my surrounds by selecting speakers A&B? When I normally listen to either the radio or a CD, the receiver defaults to my speaker A setting, recognizing only my Front L&R speakers and my Subwoofer. The 5.1 settings automatically kick in with a digital source such as a DVD.

By connecting the surrounds to both the A&B settings, am I creating any issues with impedance etc?

A First, Have you tried setting the receiver to Speaker A and Speaker B for all of your music? Secondly, A and B settings are mechanical solenoids that let you select between two sets of speakers when listening to any music, not just 5.1, so I am not sure why you get this problem. Usually, it is just the front channels that have a choice of A and B settings, not all the channels. It is a way of having a separate stereo pair of speakers in another room. It may be that your front speakers are not connected to the right terminals. Make sure they are in the "A" speaker posts.

Q I have a Grundig ST 70-700 TV, but I don't know if it can handle RGB. I an running it with an RGB signal out from the DVD right now, but I have heard that you get a picture on the TV even if it can't handle RGB, and then I would get an ordinary composite signal, and I don't want that.

A The way to tell is just to look at the picture you are getting, and check out edges where objects of strong contrasting colors are adjacent to one another, such as blue and yellow. If it is a composite signal, you will see the moving staircase artifact called Dot Crawl (see below)

 

If you are getting true RGB being processed, the picture will look a lot better, with no dot crawl.

Q My question deals with the new standard in Surround Sound Processors, being 7.1 channel capability. In considering a 7.1 configuration, what are the ideal locations and speaker types for such a setup? The question of whether to go with dipoles or direct radiators - should the speakers to the side of the viewing area be dipoles and the rear speakers be direct radiating? Or vise versa? Or should all the speakers be direct radiating? If not considering price, is there value to having full-range standing speakers at the rears, sides, or both locations? In essence, what is the ideal 7.1 setup for both home theater and future audio applications not considering price or room size?

A The concept of 7.1 includes the use of Front Effects speakers, such as found in top level Yamaha receivers. The Front Effects are to the side of the front left and right speakers. These front effects are derived from the other channels, so they are not discrete. However, 7.1 as a discrete channel concept would have the front left/center/right speakers, left and right side speakers, and rear left and right speakers. Since discrete digital channels have full range audio, ideally you should have full range speakers for all the channels. But, most of us do not have dedicated A/V rooms where we can put lots and lots of speakers any old place we want. Side speakers might interfere with a doorway for example. If your couch is at the rear of the room, it could be difficult to put two large speakers back there. You can use wall mounted speakers for sides and rear, and this is probably what many of us will have to do. But, wall mounted speakers are limited in the bass response, rather than being full range. Whether you use dipoles/bipoles or direct radiating is more of a choice based on the kind of sound you prefer. Direct radiating will give you a precise localization of the sound, and dipole/bipoles will be more diffuse. As we increase the number of speakers, it will be more and more important to make sure they all are similar in brand and models. Alternatively, just be careful to select speakers that are neutral in tonality. Then you can mix and match if you like.

Additional comments by Brian Florian: While the industry LOVES numbers in general, we all know it has a real fetish with higher numbers. I really despise the term "7.1". There is only ~ONE~ 7.1 digital sound system in existence, and that is Sony SDDS, which at this time is available only to 35mm and 70mm cinema prints.

The precedent established over the last decade by AC-3 is that the "X.X" term conveys the number of discrete main channels and discrete LFE channels. It doesn't indicate the number of speakers. Did we ever call Pro Logic "4.1"? "5.1?" We did not . . . despite every Pro Logic setup having 5 speakers and usually a sub.

A Surround EX setup has 6 or 7 speakers plus a sub, but Surround EX is not "7.1". It does not derive left and right rear channels. There is only one derived center-surround channel, but it is preferred to split it over two speakers as artistically it is a "rear" channel, not a "point in space behind you" channel. If we must call it something, "6.1" is in fact more appropriate, but I'd prefer to see us purse it as being called "5.1+" or something like that.

I combed through Dolby and THX's website, and I could not find a single instance where they refer to Surround EX as a "6.1" system.

Lexicon and its Logic7 does in fact derive separate left and right rear in addition to left and right sides so you can get away with calling it 7.1, but only if you are comfortable calling Pro Logic "4.1" (which I myself am not).

DTS-ES, though I hate to say it, is the only format which can in my mind be referred to as "6.1". Again, most people end up using two speakers for the center surround channel, but its still called 6.1.

To the best of my knowledge, Yamaha is the only one who does "front effect" speakers, and unlike Logic7, PL2, or EX, the front effects are not cardinal signals derived from main channels. They are 100% synthesized channels which create the sounds that would bounce off the front hemisphere of the room of a church, concert hall, poorly designed movie theater etc. Even though the term "7.1" is already being misused to describe Surround EX etc, I think its even more misleading to use it to describe the Yamaha setup since it is ~really~ different from the others.

I question more and more the wisdom of full range speakers for all channels, but that is a topic for breakfast in Vegas, at CES.

Q I am beginning to design a home theater in my basement. The dimensions are 15 feet deep, 11 feet wide, and 6.2 feet high, ceiling to floor joist. My budget does not permit me to lower the floor. The room is already wired for satellite/HDTV reception. I understand that optimum viewing distance for HDTV is 3.2 times the screen height. My question is what is the maximum/optimum screen size I can use in this room? The projection will be fixed/perforated. I have additional space, approximately 3 feet, behind the screen where the speakers, L/C/R, will be placed.

A Even though you will be viewing HDTV, you will also be viewing NTSC, such as DVD movies. Also, you probably will not be sitting against the back wall, but a few feet forward from that. Lastly, it will depend on the resolution of your projector. With a Sony 10HT, which has true 16:9 LCD panels, I use a 72" wide screen, and sit about 12 back from the screen. At that distance, I cannot see the pixels of the projector, and the picture is nice and sharp, using component video progressive scan. Visit several A/V stores and just try out the various combinations of screen size, projector type, and viewing distance to see what you like best. There really is no hard and fast rule because there are so many variables. When I purchased my projector, I hung a white sheet from the ceiling where I would be putting the screen. Then, I put the projector where it would be sitting most of the time (on a coffee table), and used the zoom control to see how big and how small the image would be in various situations (watching 16:9 anamorphic DVDs, satellite 4:3 TV, etc.) I sat at various distances, and then made my decision for the screen size based on what I preferred.

Q On Question #228, you say "The use of tape loops keeps the volume control of that unit out of the circuit." My question to you is which unit's volume control is kept out of the circuit using the preamp's tape loop: the receiver's volume control, or the preamp's volume control?

A If you use the tape loop of a preamplifier, the preamplifier's volume control is bypassed. If you use the tape loop of a receiver, the receiver's volume control is bypassed.

Q I live in an apartment, and I would like to get the best possible sound without making my neighbors mad. I'm looking at getting headphones, Sennheiser HD 600. I will be using them for PS2, music, and DVDs. What headphone amp would you recommend? Size doesn't matter and I would like to power two sets of headphones. Maybe tubes?

A A tube headphone amplifier would be very nice, particularly one operating in Class A. Here are some links to various products: http://www.paulhynesdesign.co.uk/page6.html    http://www.bsw-usa.com/catalog/headphone_amplifiers.html. You can also check out the Creek OBH-11, Antique Sound Lab MG Head, and the Audio Valve RKV Mk II.           .

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