Q&A # 161 - February 11, 2000

Staff

Q I recently updated my home theater system with Sony's new STR-DB830 A/V receiver and have suffered some confusion as to the best way to configure the system for use with my existing speakers (Energy Take-5 and an Energy EPS-12 subwoofer). The connection to the subwoofer is through the receiver's line-level subwoofer output. When configuring the receiver, it would seem that I should select "small" for all of the five speakers. This way the bass normally sent to the satellites will be redirected to the subwoofer (the Take-5 speakers' range doesn't start until 90 Hz or so). Unfortunately, this would seem to result in a cascade effect with the crossovers. The receiver is actively diverting low frequencies to the sub, through a crossover presumably, and then the sub is also operating its own crossover on the signal. The alternative would be to select "large" for the satellite speakers, sending the full range to them. This seems to sound OK for music, but with movie soundtracks, there is an obvious gap in the upper bass frequencies. I'm guessing that during audio playback, the receiver sends a full frequency range, line-level output to the subwoofer, while during multi-channel soundtracks, only the .1 channel is sent to the sub (if "large" is selected for the satellites).

A Generally speaking, the receiver always sends a bass signal that has been summed from all the bass in the soundtracks, when Pro Logic is being used with a two-channel stereo signal. If you set your speakers to "Small", the frequencies lower than 90 Hz are deleted. Whether or not more bass is added into the subwoofer output probably depends on the specific company that makes the receiver. Since the bass has already been extracted from the stereo signal, it would be a duplication to put more of the same into the subwoofer output jack. For 5.1, however, there is a discrete 0.1 (LFE) track that has the bass, even though it is probable that it is a duplication of deep bass in the other 5 channels (it was originally intended to have discrete deep sound effects, but it is not being used that way). Because of its discrete design, the LFE may very well get more bass from the other channels when you set your speakers to "Small". When I looked at the circuit diagram for the Yamaha DSP-A1, I saw that the LFE channel goes through a low-pass analog filter before heading to the subwoofer output jack. This means that the subwoofer output jack always has a crossover before the signal gets there, regardless of whether it is Pro Logic, DD, or DTS. Thus, it is not going to change anything as far as the number of crossovers that the subwoofer sees, if you set your speakers to "Large" or "Small." Therefore, just set your receiver to whatever sounds the best (I am assuming most or all DD/DTS receivers have the low-pass analog filter at the subwoofer output).

Q We have a Pioneer Stereo Double Cassette Deck Receiver RX-570, Multi-Play Compact Disc Player PDM 403, Dolby Surround Sound Pro Logic, and we cannot get it to record cassettes or from the CD player. We can't find papers on it to see if there is something we are suppose to do to get it to record, beside just push the buttons.

A Double cassette recorders are for copying cassettes. The ones I have seen don't necessarily record from any source in both cassette drawers. One is set up just for copying from the other cassette drawer. So, make sure you are trying to copy from your CD player into the correct drawer. Secondly, some cassette recorders require depressing a certain button before the other, rather than just pressing them both at the same time. If you don't press them in the right sequence, you can't record. This is a safety feature to keep you from accidentally recording over a prized tape. Lastly, the recording level (volume) has to be set properly, or it won't record. Usually, you can go into a record-pause mode that lets you set the level without actually moving tape through. I have seen a few that won't even let you set the record level unless there is a tape in the drawer. What I have done in these cases is to use a scrap tape cassette to set the record level, and then when I actually want to record, I replace the scrap tape with the good one.

Q Does a DSS receiver that has Digital Dolby have to have optical outputs? Do all devices (DVD, audio receivers, etc. ) have to have an optical port to be able to do Dolby Digital?

A Either optical (usually Toslink) or coaxial cables and connections can carry Dolby Digital, DTS, and regular CD digital signals. Various products use one or the other, and some have both. All the DD/DTS receivers that I have seen have both Toslink and coaxial digital jacks on the back, so all you really have to do is check which type of output your source has and buy the appropriate cable.

Q In one of your questions from last week you indicated that one should start by putting the subwoofer 12 inches from the side wall and 18 inches from the rear wall near the front right corner of the room. From where on the sub do you take this measurement - from the center of the cone, if it is a front firing sub, or the side and rear of the sub?

A Take the measurement from the side and rear of the subwoofer enclosure. It does not have to be exact. The basic idea is just to have the distances from the subwoofer to the rear and side walls unequal.

Q I just bought the Bose Acoustimass 10 Series II. I have not placed them yet nor do I have a DD/DTS surround sound receiver for the new speakers. I recently bought a Panasonic DVD-A120 (DTS capable). Now I need to buy a Dolby Digital/DTS receiver for all this. I read your recent article on the Sony STR-DB830, priced it at Crutchfield for $450, and I'd like to get your opinion if this receiver is a better choice/match than another or would you recommend something different? I, along with many others, want to keep the cost down as much as possible, but at the same time don't want to get too "low-end" or too "high-end" of a receiver for what I already have. Just trying to find a good affordable receiver that will match my recent purchases. Oh, just in case you wondering, the TV is a Hitachi 32", and all this is in approx. 14' x 17' size family room with the kitchen behind it.

A The Sony is a good unit, and there are lots of others now even less expensive, all with DD and DTS decoding built-in. They are hitting the shelves at $299 now. However, the most inexpensive ones are really just entry level units. For your situation, because of what you said, I would suggest either the Sony you mentioned, or some other model in the $400 - $500 range.

Q I have a pair of Cerwin-Vega VS-120 speakers that are rated at 5/250 watts, and I'm looking for an amplifier/receiver that will be compatible in terms of current and watts. I am confused about what I should be looking for! Can you please help me out with this and possibly recommend an amp/receiver in the $300 range. What about the Onkyo TX-8511?

A The VS-120s are 8 Ohms and 97 dB/w/m sensitivity, so just about any amplifier, including the Onkyo TX-8511 will drive them just fine. This is exactly the kind of speakers (8 Ohms and high sensitivity) to be using with inexpensive amplifiers, including those found in A/V receivers.

Q I have Apogee Duetta Signatures for my front speakers and the Apogee LCR for the center. I'm not happy with the dialog intelligibility of the LCR, and I'd like your recommendations for a replacement center channel speaker. I am most concerned about intelligibility, and secondarily concerned about matching the Duettas. Some possibilities are Magnepan, Aerial, Martin Logan Logos, B&W, and a used Von Schweikert LCR 31.

A You may be experiencing some problems with the dispersion pattern of ribbons on top of your TV. For matching your Duettas, I would suggest the Martin Logan, although it is electrostatic rather than ribbon/planar magnetic. Von Schweikert is so good, I would consider that one too, especially if you can get it at a nice price.

Q I have Phase Technology PC-100 speakers as my main speakers. I also have a Klipsch KSW-12 sub and a Yamaha center speaker  that is not connected. I think the PC-100s are relatively accurate speakers, but they seem to lack the "brightness" I think they should have. Certainly my room has many high frequency absorbing characteristics: 30 x 40, 18 foot vaulted ceilings, wall-to-wall carpets, couches, wood furniture, and piano. I'm looking to supplement the speakers with more high frequency speakers if this is the right approach. My receiver is a 5.1 channel Dolby Digital (Yamaha RXV-595). I use it for music, mostly acoustic jazz and classical. I don't have a DVD player yet. My dealer suggested I supplement the highs with either two or four B&W LM1 speakers. If I get four, I could use the surround capabilities of the receiver to get even more high frequency speakers into the room. I know the music currently doesn't come encoded for surround, but it will when DVD-Audio comes out. I brought one pair home and set them up as B channel front speakers on top of the others. They are certainly "brighter" than the PC-100s but actually seem a bit too bright, almost "tinny." I then hooked them up as the rear speakers and played a music CD, folk guitar, in Dolby Enhanced mode just to see what it would sound like, but put them in the front of the room. They basically sounded about the same as when I ran them as B but not quite as loud and with an echo. I don't know that it was all that natural and accurate a sound, and those things are important to me. I'm going to move them to the rear tomorrow to see what they sound like there (it's 3:30 am so my wife and 4 kids are sleeping or I'd do it now). What is your opinion on their recommendations and what I'm trying to accomplish? Even when DVD-Audio comes out, I'll still play lots of "old" CDs for many years to come. Can you recommend an alternative to the B&W LM1 that might be more accurate or do I already have it (PC-100)? Do you think I've just listened to too much rock-n-roll and am high frequency deaf?

A It is certainly possible that you have hearing loss, and looking at your message about your four kids, I would say you are of an age when the high frequency hearing is declining. Also, the Phase Technology speakers may just have a flatter frequency response than you are used to. Phase Technology has the PC-500s, PC-1s, and CI-100s, but no PC-100s. I would not suggest getting a bunch of other speakers to boost the highs though. You will end up with all sorts of interactions between the various speakers that are trying to deliver the same sound. Try just boosting things a bit with the treble control on the receiver. Other than that, isn't aging grand?

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