Q&A # 286 - May 4, 2002

Staff

Q While doing your review on the Velodyne HGS-18 sub, did you find it to be noisy? I've owned one now for a couple of months and find that during quiet passages in music it produces white noise that can be heard six feet away. Is something wrong with my sub? If this is normal, why do you not report it?

A This noise is normal for the Velodyne servo-feedback subwoofers. I (JEJ) did mention it in previous reviews of their subwoofers, but I have become so accustomed to it, I don't always describe it in every Velodyne review. The servo-feedback occurs several thousand times per second, so that creates a sound like a sigh. However, the benefits of servo-feedback in a subwoofer are considerable. Here is a spectrum from a Velodyne FSR-18 where I used a 20 Hz sine wave input and measured the THD with a 109 dB output close to the subwoofer. This is spectacular performance that is directly a result of the servo-feedback. At 20 Hz and high output like this, much more THD could be expected with non-servo-feedback subs. That does not mean other subwoofers sound bad, just different. Harmonics in a subwoofer are not necessarily irritating. Many people like the sound of the harmonics, such as in movie sound effects. Since the really low frequencies are felt but not heard, harmonics add the sense of hearing them as well as feeling them. It all depends on what appeals to you.

Q I a planning to buy Mirage Omnipolar speakers (two OM-7, one OM-C2 center, two OM-R2 rears) all rated as 8 Ohms impedance. Will they be compatible with a Kenwood VR-5900 receiver rated at driving 5x130watts @ 6 Ohms? Is there a problem with this impedance mismatch?

A This is not a mismatch. The Kenwood describes the output at 6 Ohms because it looks better in the brochure. It will probably deliver 5 x 110 watts at 8 Ohms. You will be fine with the combination you are purchasing, because receivers love 8 Ohm loads. They don't perform very well with lower impedance speakers.

Q  I'm trying to build a very high level stereo and surround system (Revel, Bryston, Velodyne) and the only really good processor that might rival two-channel stereo preamps seems to be the Meridian 861. I was going to hang a two-channel processor off of the two front channels of the surround processor, but, it doesn't seem right to spend that much money on interconnects, and besides where would I put the sub? I'm really stuck on the processor selection. I see BAT and Parasound are coming out with new processors, but does anything compare to the Meridian? Should I wait?

A Do you plan to listen to analog sources? If not, the 861 is all you will need. Once you listen to an 861 using one of their music modes, like Trifield or Pro Logic II, you might not listen to two-channel ever again. I know I (Stacey) don't.

Q I just read the PS2 DVD player benchmark/review by Stacey Spears in Secrets, because I just bought one and wanted to know more about it. I didn't understand much because it was very technical. But I was really worried when I saw that under "Component Channel Timing" it was rated "Poor" and the reviewer said, "Not since the Pioneer DVD players have a seen a delay problem this bad. This is unusual for Sony." I am currently using the composite AV cables provided by Sony, while waiting for the component cables to arrive. I wonder: Does this "delay problem" mean the video quality will be poor if the component cable is used? If so, how much? And will I be able to experience better video quality by using S-Video cables?

Please help me and answer me this questions since no other website has made such an in-depth analysis about the PS2's DVD video playback quality. And since the same video output will be used for movie playback as well as gaming, I'm trying to get the best possible picture.

A The PS2 is a game console first and foremost and should be treated as such. In absolute terms, any DVD player will produce an image that is far superior to VHS and broadcast TV. In relative terms, the PS2 is just ok for a DVD player. There are better and less expensive choices, but I am sure you bought the PS2 primarily for games.

Q I am currently looking at purchasing a DVD-Audio player. It looks like I have it narrowed down to the Panasonic RP91 or the Denon 1600. The Denon does have bass management and it has the Faroudja DCDi chip. But I am not to sure of the quality and performance that they are really pulling from the chips. The RP91 does seem to be a proven player.

A The Denon 1600 and Panasonic RP91 will probably have similar performance, except for the DCDi.

Q I have Sherwood RV5106 A/V receiver with DTS, DD, and 6 channel analog input. I have this linked up to a DVD player with DTS, DD, and 6 channel analog output. I have them linked by RCA interconnects using the direct output/input channels.  When I set the DVD player to analog 6 channel output and the receiver to the 6 channel analog input, I get surround sound but I only hear music and things such as wind and footsteps but no voices. Is there a problem with the DVD player, the receiver or the setup and what I could do to eliminate the problem?

A Somewhere along the route, you are missing the center channel signal. I would suggest using the digital output of your DVD player and let your receiver do the decoding. If your DVD player only sends DTS through the 5.1 analog out, then try reconnecting the six cables in different combinations to see if one of the cables is defective.

Q I recently upgraded my stereo system to 5.1 home theatre. I decided to go with NAD components, T531 DVD player, and T751 receiver. I am using Mission M70 series for the speakers. My Toslink cable is Acoustic Research as are my speaker cables. Last week whilst watching a rented DVD (Top Gun) the picture and sound started jumping in certain places. Concerned that this equipment cost me an arm and leg, I took the DVD player to the hifi shop where I purchased everything. The DVD player gave no problems in identical equipment. I suspected a problem with my DVD player and returned it. The after sales service is excellent at this hifi shop so the unit has been exchanged with another one (same model). I connected it up again and now have found some of my other DVDs freezing in certain places. So it seems if the original DVD player was not at fault. What else could be the problem? Can the Toslink cable cause this, or is it the decoders in the receiver? Any opinions would be appreciated.

A DVD players are digital and depend on clean AC. I suspect your AC lines are very noisy and this is causing your player to freeze up. Unfortunately, mass market players have minimum power supplies, and some of this noise in your lines is getting through to the digital circuitry. I would suggest buying a good power conditioner like the PS Audio P300 to get your AC supply back to a clean sine wave. We tested a P300 with a portable DVD player some time ago, and it resulted in less audio dropouts on DVDs. This all assumes you used the same actual DVD discs along with your own player when you tested it at the store, and the problem did not occur. Otherwise, it could just be some dirt on the discs. The tracks on DVDs are very narrow, and they are subject to problems if they have scratches or dirt.

Q I am currently looking for a subwoofer to go with my Snell "D" Reference, C.5, and SR.5 speakers. I am currently using an Adcom GTP 600 preamp/tuner, GFA 6000 amp, and Panasonic RP91 DVD player. I am thinking about upgrading to the GTP 830 preamp/tuner, or trying to find a GDD-1 D/A converter to use with the GTP 600. I am looking for a decent subwoofer for about $1200. Is the Snell PS.10 really any good below 40 Hz? I am thinking primarily about HT uses.

A We are publishing a review of a Snell home theater package next week, including the PS.10mk2 subwoofer. It performs very well below 40 Hz as you will see in the review.

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