Q & A

Q&A # 136 - September 1, 1999

Staff

Q I currently own a Yamaha DSP-A1, and I want to improve the amp section of the unit. I was thinking about purchasing the Anthem MCA2 or MCA3. What is your opinion on these amps? Will they sound better then the amps which are currently in the DSP-A1? Also if not the Anthems, do you guys recommend another amp to purchase.

A The company that markets the Anthem is supposed to be sending us one for review. We don't have it yet, so I can't comment on how it sounds. The DSP-A1 is a good unit, but like all mass market products, it does not have an amplifier that does well with anything other than 8 Ohm speakers. If you have 8 Ohm speakers and don't play the system to room shattering loudness, the built-in amplifiers do fine. Otherwise, you should go to an outboard multi-channel amplifier that has significantly more power, such as the Sunfire CinemaGrand or CinemaGrand Signature. We reviewed the CinemaGrand and will be publishing a review on the CinemaGrand Signature soon. They are both very good amplifiers, rated at 200 watts rms/ch and 405 watts rms/ch respectively, and will drive any speakers on the market. The Sunfires use digital switching technology, so they run stone cold, being very efficient. If you prefer the Class A/B kind of amplifiers, then try something like the Bryston 9B-ST or Cinepro 2k5.

Q I have an Onkyo DVD player. I can play AC-3 DVDs through this and my AC-3 receiver. I am very confused about DTS though. Up till now it has been a non-issue since I don't have a DTS receiver. I am about to buy a DTS receiver, and my first thought was my Onkyo should have no problem sending the DTS to my receiver. Others have told me this isn't the case, and that I need a DVD player that is capable of sending DTS. This makes no sense to me. Isn't the DVD just a pass-through of the raw digital signal? What special processing does a DVD player have to do for DTS to send it in raw format to a DTS receiver? The only thing I can think of is that the DTS data is in a different part of the DVD, but I doubt that is the case. Is it true that DVD players that can pull and pass AC-3 may not be able to pull and pass DTS?

A Back when DTS was just about to come out, they were using the same kind of data presentation that DD was. If this had been left alone, all DVD players would have been able to output the DTS bitstream. Because of legal issues, DTS had to use a different data presentation, and this resulted in early DVD players not being able to recognize the DTS signal. So, it was not until about 2 years into the DVD player manufacturing that players were designed to recognize the DTS "Flag". Unless your DVD player has a logo on the front that says "DTS Digital Out" or some other notice that it is DTS compatible, it is unlikely your player will recognize DTS DVDs. However, it will play DTS CDs, and actually, there are many more DTS CDs (5.1 music) than DTS DVDs (movies), so go ahead and get the new receiver.

Q My system is comprised of an Onkyo TX-DS747 audio/video control tuner whose front pre-outs drive an Onkyo A-807 integrated amplifier (80w rms/chan) whose outputs drive a pair of Infinity Reference 50 speakers. I am using the A-807 to drive the front speakers because it is a good quality amp which was my first purchase when I started building up a hi-fi system. It also relieves the transformer in the TX-DS747 to be able to supply more current to the center channel and surrounds during transients etc. The AV tuner's center channel output (80w rms) drives a Polk Audio CS275 speaker and the surround outputs (45w rms/chan) from the AV tuner drive a pair of Polk Audio RT5 bookshelf speakers. I am running AC-3 and due to the wide dynamic range of DVD, I feel that my system is a little underpowered for this format. Pro Logic is fine, and there is no need for me to crank the volume beyond 10 o'clock to upset the neighbors. With DVD, I sometimes have to crank the volume to 12 o'clock to get a substantial output. My frontstage speakers are rated up to 150w rms each, and the surrounds are rated up to 125 w rms each at 8 ohms. I have been eying the Onkyo M-501 power amp which is rated at 170w rms/chan, and it is affordable. If I bought and used this amp to drive the Reference 50 front speakers and moved the A-807 to the surround pre-outs to drive the RT5s, would I improve the volume as well as the fidelity of my entire system ? The dealer I bought my system through reckons that I should leave my system as it is because in order to improve the output and fidelity, I would have to upgrade all my amps and speakers to high grade audiophile components which will cost me more than what I purchased my entire system for. Please give me your opinion.

A I think that the dealer has a point, but not in all respects. I've owned some Onkyo M-504 amplifiers at one time, actually four of them , which I assume are somewhat related to M-501s. They were rated at approximately 150 watts into 8 ohms, had dual-mono power supplies, smallish filter capacitors, and two pairs of transistors per channel. Generally speaking, they had a wonderfully clear midrange, slightly crispy treble, and responsible bass that left a little to be desired in terms of oompff way down deep. Passive bi-amping with the amplifiers improved bass response dramatically, as it split the current demands of the speakers between the two amplifiers, even though they still swung full voltage into their loads. The passive bi-amped setup didn't play much louder, since the combined power supplies couldn't swing any more voltage than before, but they did play cleaner at higher output. My gut feeling is that, yes, an extra amplifier will improve the overall fidelity of the system, but only marginally increase loudness level. Then again, if you have cleaner sound, you may not feel as compelled to turn up the volume. I don't agree that any large improvements in both dynamic range and fidelity would require an entire overhaul of the system. If the amplifier side of the system truly is the weak link, it may make sense to look into bigger 5-channel amplifiers, or a 3-channel amplifier in combination with that integrated you like to power the surrounds. After all, in 5.1, the center channel is the most important. On the other hand, ACTIVE bi-amping DOES increase dynamic range, as it lessens the required voltage swing into an amplifier's load, and can be as simple as buying a powered subwoofer and setting all five channels to "Small" in the bass management options. Not only does it increase dynamic range, but lower distortion from the left, center, right, and rear speakers, while hopefully extending the lower-end response to boot.

Q I have a question about subwoofer level and room interplay. My system is comprised of a Yamaha DSP-A1, B&W CC6 center, four B&W DM602s (front and surround), and a Sunfire true sub MK II. I've got all the speakers set to small (crossed over at 90 Hz), and the sub crossover set to the lowest setting (35 Hz). My problem is that I am getting some peaks and dips in the listening position. My room is 13' by 13' by 11' and according to the Avia disc, I've found a dip at 70 Hz and a significant peak at 58 Hz. The 58 Hz peak is causing movies to seem excessively boomy. When I unplugged the sub I found that the main speakers were producing usable bass down to 45 Hz which could be a reason for the boominess. I can't lower my subs crossover any more, and if I lower the volume I get practically no output at 20 - 30 Hz.

My questions: I have the opportunity to get a different sub (I'm looking at the Sunfire signature). Would this help with the lower end and possibly the 70 Hz dip? My placement of the sub not in a corner because I was getting too much energy at 50 Hz - 60 Hz. Is there anything I can do with placement to help? I was thinking about an external crossover as the Yamaha gives me limited resources for adjusting bass, but most of my sources are digital (Satellite uses Toslink, DVD coaxial digital, and CD player uses Toslink). Will an analog EQ be able to tweak digital sources or should I get something specifically for the sub? I know this is a rather long question but I would really like the advice. As it is, I've either got too boomy soundtracks where punches sound like thunder; or too damp soundtracks where explosions sound weak.

A The problem is not your subwoofer or your other speakers, but the room. Standing waves cause peaks (augmentation) and dips (cancellation). However, setting the bass management to "Small" for all the speakers will cause a dip between 90 Hz and 35 Hz, according to your settings. This is probably the 70 Hz dip you are seeing. The DSP-A1 is removing everything below 90 Hz in the speakers and sending it to the sub. But, you have set the low-pass on your sub to 35 Hz, which means the sub is only reproducing signals below 35 Hz. So, between 35 Hz and 90 Hz, you get no signal. On the other hand, you should not be getting any 45 Hz output from the main speakers with the sub out of the circuit, because your DSP-A1 bass management has removed everything below 90 Hz. Make sure your bass management is set to "Small" for all the speakers, not just some of them. However, you will get a better soundstage if you can work out some room treatments to get rid of the 58 Hz peak (rearranging furniture, opening or closing doors, pillows in corners, etc.), and set the speakers to "Large", since sound in the 50 Hz and above range is directional. An EQ would also work, but that would require you to get an outboard five-channel power amplifier, so that you could put the EQ between the pre-outs of the DSP-A1 and the inputs of the outboard amplifier. Try moving the main speakers farther away from the wall along with some room treatments.

Q I have four Carver ALIII+ speakers, two for my mains and two for my rears. My Center is the Von Schweikert LCR-31 and my sub is Velodyne F1800-RII. I recently purchased the Lexicon MC-1 and am now in the market for a pair of dipoles for use as my side speakers that can match well with the powerful ribbons. I don't have room on the sides for two more Carver's or I would get them. Suggestions so far are the NHT HDP-2, the Klipsch dipole, or B&W dipole. Any recommendations?

A Ribbons have a transparent quality of their own that transcends the mere fact that they are dipoles. Therefore, I would suggest that you stick with ribbons for the sides. Since size is an issue, you might consider something like Newform Research, which makes small ribbon speakers such as the Newform R8-1-30.

Q I have a Harman/Kardon 5800 amp teamed with the new Sherwood/Newcastle 9080R preamp. First, I would like to say that I love the way they sound, with my Klipschorns for main and more Klipsch for the rest of the home theater. It was a vast improvement over my old Yamaha. Most of the time the amp works flawlessly. However, on occasion, the amp has a VERY noticeable mechanical hum. My stereo is not on a dedicated circuit. When the hair dryer is turned on, the amp will either begin to hum immediately or sometimes it will not start to hum until the dryer is turned off. The thing is, that although the stereo is not on a dedicated circuit, it is also not on the same circuit as the hair dryer. I mention the hair dryer because it is the most noticeable, but I believe the hum comes and goes to some extent with other appliances also. I would like to know if it would help to put my home theater on a dedicated circuit, and if there is some device that might stop the interference from reaching my system. I would like to make it clear that the hum is coming directly from the amp and not the speakers. I have all of my system, DVD, VCR, and Sat, going through one of those cheap long six plug extension cords with circuit breaker. It is very frustrating so any help would be appreciated.

A Electrical noise and voltage changes produced by all kinds of things, such as motors and rheostats (variable brightness controls for lights) are very annoying. The AC coming into our homes is very dirty. It is full of RF and various spikes and dips from our neighbors appliances as well as our own. They cause noises in the audio, but also in video. If you have ever seen a horizontal line that slowly makes its way down the TV screen, over and over, it could be due to using a variable lighting control set to the middle value. Moving it to full on or full off can correct this. Mechanical hum in transformers is also a manifestation of several problems, including these darned variable lighting rheostats. The only solution may be one of the new AC line conditioners that takes the incoming dirty AC, converts it to DC, and then resynthesizes 60 Hz 120 Volts cleanly from the DC. We are testing one now, and it is not all that expensive for the 300 watt version, which should probably do the job for you. It has a voltage regulator too, which means that regardless of whatever variations exist in the incoming voltage (down to 90 Volts), the output will stay at 120 Volts. I think this is going to be a revolutionary product for making home theater equipment noise free, so wait until we publish the review before you make any changes to your system.

Q I recently picked up some used Luxman equipment including an R-1050 Receiver, L80V amp, and K120 cassette deck. I remember admiring Luxman products back in the late 70s and early 80s, but it was expensive back then and I couldn't afford it. Was/is Luxman considered high end or just expensive mass market equipment? What about sound quality? Any comments? And finally, is it worth considering using any of their "vintage" equipment in a modern-day home theater system (specifically power amps and the amp stage of the L80v integrated amp?

A Luxman is high-performance equipment. They may have taken on a Mass Market reputation, simply because they are made in Japan, the seat of mass market equipment. It is very expensive because they use high quality parts, and also because they don't make them in large numbers. As far as I know, they are still in business (http://www.luxman.com). The vintage equipment may be very, very good. If you are delighted with the sound, you are home free. The amplifiers should be great for home theater. You could run the front left/right pre-outs from your DD/DTS preamp through the pre-ins on the L80v, and then connect your CD player to another set of inputs on the L80v that use the preamp stage in the L80v, so that you use the entire L80v for CDs, but the home theater processor for DVD.

Q I read your review on the Yamaha RX-V995. It was a great article. I have a couple of questions for you if you don't mind. I just upgraded from a 870 to a 995 yesterday. Now, my setup consists of Klipsch center and rear channel speakers. I have two Pioneer main speakers (don't laugh, my wife won't let me get rid of them). I also have a Toshiba 3109 DVD player and a JVC hi-fi VCR, but I don't have a subwoofer. Now my question to you is, do I need to change the speaker wires to get optimum sound? If so, what kind of wire should I use (without it costing an arm and a leg, since I have two kids)? Also, is it cheaper to buy the speaker wire with the ends on it or should I crimp the ends on myself? I have the digital cable running from the DVD player to to the receiver and the S-Video running directly to my television. Is there anything wrong with that setup?

A I'm not laughing at all. You should see what I started out with. The St. Vincent de Paul refused to take it ;->. Anyway, even with a nice mass market system, having a decent set of cables will help. For your situation, I would suggest buying bulk 16 gauge zip cord from an electrical supply. Twist the wires on the end and insert them into the holes in the speaker binding posts on the receiver. If you want to go for a nice step up, then get Nordost 2-Flat, which also comes in bulk, but you can get them to put banana plugs on the ends as long as you are careful to determine the proper lengths before you order them. It will cost a couple of dollars per foot, compared to about 30 cents a foot for the zip cord in bulk.

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