Q&A # 239 - July 28, 2001

Staff

Q I have an Onkyo TX-DS 595 receiver, two Mission M74 speakers in the front (M71 for surrounds). My question is about subwoofer hook up. I will probably buy an Infinity IL100s, a Velodyne CT150, or a Magnat Omega 380 in the next few days. As I am listening to 50/50 music/HC, what is the best solution to connect the sub? Using the sub pre-out from the receiver to the line-in on the sub, or to connect the main speakers to the speakers input on the sub (and of course setting up my speakers to LARGE on my receiver, and sub to OFF)? With this 2nd solution, I will have the advantage of the sub while listening to music, and I can of course just switch off the sub if I do not need it. The other advantage of this second solution is with Dolby Pro Logic II. It doesn't have a LFE signal, so I'll have the advantage of the sub even with DPL-II if connected through main speakers. What would be the advantage of connecting the sub with the sub pre-out?

A Using the sub pre-out to the line-level input on your subwoofer will be more advantageous I think, because using the speaker-level inputs will mean you are using the speaker-level outputs of the subwoofer back to your speakers, limiting their response to about 90 Hz and above. The Mission M74s are floor-standers and full range. So, just use the sub pre-out to the line-level input on your subwoofer and set the low-pass crossover to 50 Hz.

Q Have you ever listened to any Acoustic Zen cables? And might you know anything about their "Gargantua" power cord?.

A Acoustic Zen (http://www.acousticzen.com/) is one of many, many cable companies out there, and they appear to be a small organization that hand-builds them. Sometimes these are the most interesting products, so we have ordered some for review.

Q I recently purchased a new home theatre setup consisting of a Yamaha RX-V800 amp, M&K 750 THX speaker system ,550 THX rears ,and V-1250 THX sub. The problem I'm having is that at curtain volume levels the amp just cuts out. I would rather not go back to the store, as I am annoyed to deal with them.

A I assume you are talking about the receiver. It is cutting out because you are putting too much heavy bass through it. I would suggest turning the bass control on the front panel down a bit, and turning the subwoofer volume up to compensate. This will reduce the low bass going through the receiver's power amplifiers.

Q I want to record the video footage of my wedding on a VCR tape onto another to give to my relatives, but I do not know how to set up the video players to do this task. Please can you help?

A Yes, and it is very easy to do. You have the two VCRs sitting side by side. Put the original tape in VCR A. Put a blank tape in VCR B. Connect the audio and video output jacks on the back of VCR A to the audio and video input jacks on VCR B (these are usually sets of RCA jacks with red and white for the audio and yellow for the video). Connect the audio and video output jacks of VCR B to your TV so you can monitor the recording. Make sure both tapes are rewound to the beginning. Simultaneously press Play on VCR A and Record on VCR B. When the video is finished playing and recording, press Stop on both machines. Rewind the tapes and press Play on VCR B to see if it recorded properly.

Q I have two Klipsch La Scala for front , two Heresy for the rear, and a dual 8" 4 way custom Kipsch cabinet for the center. I am looking for advice as to which power amplifier to drive this system. I prefer the monoblock McIntosh tube gear, but that may not be in the budget. Also my son says this stuff is outdated and I should get something new. Help!

A The day will come when that son of yours will love having those Klipsch, so don't get rid of them. You can power those old beasts with just about anything because they are so sensitive. If you like tubes, there are lots of choices out there for reasonable money, such as Audio Electronic Supply (http://www.audioelectronicsupply.com).

Q What are your thoughts about bypassing my Velodyne subwoofer crossover and running my satellites at full range with the sub providing supplemental bass via the preamp output? While I suspect we all advocate listening for ourselves, I wonder if (generally speaking) you are an advocate of going with the manufacturer's crossover setup, or trying these more "home-grown" approaches?

A The sub-out on receivers has a crossover in the signal path, while the speaker output of the receiver do not. Unless you have a crossover in/out switch on your particular Velodyne, there will be a crossover in the signal path regardless of whether you use the line-level input or the speaker-level input. Good bass management is just now beginning to show up in hi-fi products, so I think it is better to use the line-level subwoofer pre-out to your subwoofer, and just live with two crossovers in the path for now. Because it is the low frequencies, I have not experienced problems doing this. Run your speakers full range, and set the Velodyne low-pass to 50 Hz.

Q I'm building a home theater in the basement, and I was wondering if a downward-firing subwoofer or a side/front-firing sub would be better on a carpeted concrete floor?

A Carpeting will not absorb low frequencies like it would the high frequencies. That is why downward-firing subs are manufactured. However, front-firing subwoofers are much more common these days than downward-firing. Just get the one that you like best. I am sure it will be fine on your carpet regardless.

Q I have been looking at a couple of receivers. One is the Sony STR-DE845, and the other is the Onkyo 484 . I'm confused as to which is a better model? One has 100 watts x 5 in surround mode the other is 55 x 5 channels of high current. Which is better, 55 watts of high current , or 100 watts?

A You are getting caught in the marketing spec game. The one that is rated at 55 x 5 is probably more conservative, saying essentially that their 55 watts can play into a low impedance load (4 Ohm speakers). The other one, 100 x 5, is more aggressively rated, but it won't deliver big watts into low impedances. High current is a relative term. If an amplifier is rated at 10 watts into 8 Ohms, 20 watts into 4 Ohms, and 40 watts into 2 Ohms, it could be called high current, in relation to its power. My guess is that both of the receivers you mention will perform about the same.

� Copyright 2001 Secrets of Home Theater & High Fidelity
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