Q&A # 199 - September 29, 2000

Staff

Q I'd like to venture into the surround sound world, but I need to know a couple of things. I must use a room 22' long by 11' wide. My setup will be on one end, approximately 11' x 11', so my rear speakers will be a little bit less than 11' from my front speakers and as far apart as I choose to place them, with the 22' length restriction, of course. Without getting into size and brand of speaker, do I really need five speakers, is a sub-woofer necessary, and could I benefit from a center channel? If I I buy a pretty good receiver, such as the Onkyo 575SX, will this necessitate five speakers and a sub to maximize the receiver? I'm trying to get better quality from my CD, DVD, Video, etc. but without overkill.

A In my opinion, regular two-channel CDs do not really benefit from surround sound, because the DSP that is used to convert two-channel to five-channel has an artificial quality to it. CDs specifically programmed for Pro Logic are alright, but most CDs are not made this way. For stereo TV, it is the same. Most programs are just stereo, and not programmed for surround sound. For DVDs, it is a different story. Just about every movie produced in the last couple of years has 5.1 DD surround sound, and the DVD versions have this on the disc. It is necessary to have a 5.1 receiver with DD (all the new ones have DTS too) so you can get the proper 5.1 digital surround sound. You can use an old Pro Logic receiver and the two-channel analog outputs from the player to get some surround sound, but it is no substitute for true 5.1 digital surround. However, you can get the 5.1 receiver and not get all the speakers at once if you are in a budget situation. You will need at least two to start, using the receiver in two-channel mode. Then add the center (yes, it's a benefit), and finally, the rear speakers. A subwoofer is critical if you like action movies, so you will need one as soon as you can afford it.

Q I am an audio buff who is looking to replace a CD player (Teac CD P1100). Great  audio is my prime consideration, as I purchase Mobile Fidelity, DCC, as well as  improved existing titles (I've purchased numerous Steely Dan discs of the same title
because of improvements). All discs are played through Celestion 7000 speakers powered by  a 100 watt Yamaha AX592 integrated amp. I am thoroughly confused as to 16, 20, or 24 bit mastering. Now I have been informed that a DVD player will sound
better than a CD player. If this is this case, having a DVD player would be a bonus. I  also play many CD-Rs of "imported" titles . Again, audio is primary, and DVD is secondary. I simply would like to own a good high fidelity CD player without going nuts (Super
Audio CD for example).

A If the DVD player has dual lasers, it could sound as good as a dedicated CD player, but not better. SACD and DVD-A have not taken off yet, because initial SACD players were very expensive, and DVD-A players are just now hitting the market. Within a few months, there should be DVD players that handle DVD-A and SACD, besides regular DVDs. Since audio is your main concern, I would suggest waiting for one of these. They probably will be in the area of $1,000. From everything we have heard in person so far, SACD and DVD-A are substantially better than regular CDs.

Q I enjoyed your review of the AudioSource AMP 3 and am thinking of buying one. I would like to know if you tested this amp at all at a 4 ohm load, and if so, how did it handle it? I know it says that it is stable down to 2 ohms, but I'd just like to know some real world results with it running at 4 ohms.

A We tried it with several speakers, including some that dip down to low impedances, and it worked well. They may have actually lowered the price since we reviewed it.

Q I would like to ask a question regarding my home theatre setup. I use NHT SuperZeros for the front speakers and a M&K MX-125 MK II for my subwoofer. The published frequency response of the SuperZero is 85 Hz to 25 kHz +/- 3 dB. The subwoofer is connected to the subwoofer pre-out of my Onkyo receiver. The low-pass filter of the pre-out is set to 80 Hz. My question: is there
a 'hole' in my setup in the 80 Hz to 85 Hz frequency range since the SuperZero can only handle frequencies from 85 Hz up?

A No, you would not have a hole. The "slope" of the woofers in your NHTs allows some signal to be reproduced below 85 Hz, in fact all the way down to 20 Hz. It is just that the output drops as you go down in frequency. There is also a slope associated with the 80 Hz crossover in your receiver and your subwoofer, and this allows a small amount of signal to pass above 80 Hz, falling off as the frequency goes up. So, I think you have your system set about right.

Q Under "Further Observations and Summary - January 17, 2000", Stacey Spears said he had acquired an Excalibur Plus from Camelot Technology.   I was wondering what his thoughts were on the product or is there a Composite-to-S-Video converter your team liked better?

A The converters are designed so you can use something like a VHS-VCR, along with your DVD player, LD player, DSS, and other S-Video sources all being connected to a receiver and its single S-Video output to your TV. In general, you can't mix and match composite RCA video inputs and S-Video inputs to have a single video output in the receiver. None of the converters will match the S-Video signal that is already S-Video when it comes out of the source, but they have their purpose as outlined above. Now that we have to deal with sources and receivers that have component video, it would be nice if receiver manufacturers would build signal mixing and splitting into the products so we don't have to worry about looking for converters.

Q I would like to know the best way to connect my home theater components. My system consists of the following: A 68 cm stereo TV, a stereo VCR, a DD/DTS DVD player, an 85 w/ch DD/DTS 5.1 channel receiver, two front speakers, a center speaker, and a set of surround speakers, but no subwoofer. The connections I currently have in place do not seem to be correct. There are times that after I turn off the TV, sounds are still coming from the receiver, and there are times after I turn off the TV or the DVD, I can't turn off the receiver thru the remote control. There is definitely something wrong with the installation.

A This is an issue with your remote control. Usually, you have to select the component that is being activated by the remote, such as the TV or receiver. Then you can turn that component on or off. So, once you have turned your TV off from the remote, you need to push the receiver button, and then you can power it off. If your TV is off, you can still get sound from your receiver if your VCR is serving as the TV channel tuner. Also, if you change the TV source input, such as DSS, DVD player, or VCR, and the new input component is not turned on, the video screen will go blank, making it look like the TV is off.

Q  I have a question concerning sub connections stemming from your comments in a previous Q & A. In it you stated:
"With all the subs connected to one output, you could very well have a problem, as the impedance that the output sees will drop considerably, and this taxes the driver stage. You might end up having to use another preamplifier in between the sub-out on your receiver and the subwoofers, to boost the voltage."

This statement is confusing to me since the person asking the question seemed to be using line level (RCA) connections, not speaker level. Are you saying using RCA connections can impart impedance problems to the sub's driver? I am curious, since I just had a subwoofer driver failure. I have recently moved out of an apartment into a house where I can actually run my sub all the time. It only lasted 3 months in the new place, at moderate volumes.

Did I do something to damage it? The sub is connected by RCA line levels using a Y-adapter from my main pre-outs - one set goes to an external amplifier for my front mains and the other set goes to the sub, so I don't have to contend with two filters in series. Is this set-up damaging for the sub somehow? I wouldn't have thought so until I read your statement above.

A When you have multiple inputs (subwoofer line-level and another power amplifier) connected to one line-level output (main pre-out RCA jack on your receiver), the impedance that the receiver is now driving drops, just as the impedance that your power amplifier speaker output terminals sees drops to 4 Ohms if you connect two 8 Ohm speakers to the one set of terminals. This lower impedance is difficult on the receiver's line-level output circuit, just as 4 Ohms is more difficult for a power amplifier's output circuit than 8 Ohms. Using a single Y adapter to split your output for driving the subwoofer and another power amplifier should cause no problem for your receiver, subwoofer, or power amplifier. Your subwoofer became defective for some other reason, I am sure. You did not damage it from your described connections.

Q You wrote in Q&A #191 that "For DTS, you would need the decoding in the preamp or receiver anyway, since DVD players don't offer 5.1 analog out for DTS". But what about DVD-A players with 6 channel output? Will DTS go through it?
A It appears that some of the new DVD players have DACs that will handle the DTS signal, sending 5.1 analog to their 5.1 RCA jack outputs. So, they will provide you with both DD and DTS 5.1 analog out. You need to check the specifications of any new DVD player you are considering carefully though, including players that have DVD-A capability, since this is a design change that is in the middle of happening right now.

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