Q&A # 19 - July 8, 1997
Q I have read that the currently available DVD players all put out a Dolby digital signal, but that if DTS encoded discs ever become a reality, these players will not be able to handle the bitsream emanating from them. Is
this true? Are current DVD purchasers locking themselves out of DTS if this format becomes viable on future DVD players? I am interested in purchasing a DVD player but will wait until I know that my player won't be obscelent as soon as I get it home!
A DVD players will transmit the digital data, whether it is AC-3 or DTS, from the digital output jack on the back of the player. This needs to be connected to the digital input on the receiver. Depending on your receiver and outboard decoder setup, you may need to test various configurations to play both AC-3 and DTS discs without having to reconnect the cables, but DTS discs do play on DVD players. We don't have DTS movie DVDs yet, but we tested DTS CDs on our Toshiba 3006 DVD player, and they work fine.
Q I'm new to Home Theater and high-end audio. However, I've been learning quickly thanks to the internet. I hope to
purchase my first real component this 4th of July weekend and build from
there, getting a new piece every few months. I was inspired by the article
you wrote that utilized the Yamaha RX-V990, and then added an external three-channel amp to beef up the front and rear channels. I really like this approach because it will allow me to have some fun while I'm saving my pennies for a decent multi-channel amp. I will be using the system about
50/50 audio and home theater. I listen primarily to contemporary Jazz with some
progressive rock, and like to watch action/adventure flicks with loud
dynamic sound. My listening room is 20' x 20', and I'm driving two Infinity
SM150s and two Pinnacle PN7s, which I hope to replace soon.
Q1) I can pick up the 990 for $575 (a Demo unit w/warranty), but with
the introduction of newer <$1000 AV receivers (i.e., Yamaha 692 & 992,
Denon 2600 & 3200, HK, Amfi, Sherwood, Pioneer D606S, Kenwood 1080, etc.), would you still go with the 990? If so why, and if not which receiver would you select?
Q2) If it were between the Denon 2600 and the Yamaha 990, or the 3200 & the 992
which would you go with, and why? I've heard the Denon has a better amp and
Pro Logic surround and the Yamaha has better DSP. Is this true?
Q3) What would be a good new or used 3 or 5 channel (150-200 wpc) amplifier to look for when I'm ready for that step? I've heard good things about ATI.
Q4) I would like to get a decent Center & Subwoofer before I replace my
SM150s & PN7s. I'm looking for new or used, best bang for the buck,
but something that will accommodate the larger amp down the road. What
would you recommend for center channel speaker and subwoofer now, and Fronts & Rears down the road?
Q5) Other components I will be adding/replacing soon include:
Cables - low end Audioquest, Monster, or ?
VCR - Best Hi-Fi for under $300 - need cable box control?
AC-3/DTS Decoder - If I go non AC-3 receiver, prefer comb AC-3/DTS if one
exists?
DVD player - heard good things about the Sony 7000?
CD Player - Multi preferred?
TV Monitor - 32 or 36" under $1000?
I realize this is a great deal of questions to respond to, but it seems hard
to find knowledgeable, objective, audio experts on the Internet or retail
outlets. So I thought I would fire away and hope for the best. I'm sure
there are many other audio newbies that would benefit from your response.
Thank you again for this wonderful Web-Site.
A The Yamaha RX-V990 is a very good receiver, and yes, Yamaha is reknown for their DSP. If you can get one for $575, do it, as long as the warranty is full coverage. There are many new models from all the various manufacturers, and of the ones that have AC-3 now built-in, most have done away with the 5.1 set of inputs on the back for adding outboard decoders (if they had the 5.1 inputs to begin with). If you think you will want DTS down the road, the 5.1 inputs are still necessary, so you should check for them on the back of any receiver you consider. Fortunately, there are companies, such as MSB Technology, who can add DTS boards to many existing receivers that don't have the 5.1 inputs, but there are other surround technologies on the horizon, such as Circle Surround, that you might want to add eventually. So, for our readers who are in the market for a new receiver, and who like to maintain forward compatibility, focus on the receivers that still have a set of 5.1 inputs.
We have reviewed a number of nice multi-channel amps, but if you want to stay with 150w - 200 w/channel, then look at the Sunfire Cinema Grand and Adcom. In particular, if you want to add a three-channel amp now, and two more channels later, the Adcom components we reviewed will perform nicely. We are just about finished with the reviews of Bryston two and three-channel amplifiers.
For the speakers, it will be best to stick with the same brand for the front and rear, especially with digital surround, so as to maintain the same tonality all the way around. Take a look at this week's review of the Platinum Audio Studio-3s. Jim Moretti, who wrote the review, loved them. Best bang for the buck, in terms of subwoofers, probably goes to the Sunfire Subwoofer. Good luck on finding a used one that someone is willing to give up.
For cables, we like Nordost and AudioQuest, but we have not tested Monster Cable yet. Monster has a huge product line, and we have heard very good things about their stuff.
For VCRs, I like Mitsubishi.
DVD Player - The Sony 7000 appears to be the best, with the Toshiba 3006 in second place.
CD milti-players - Sony and Denon.
TVs under $1,000 - Toshiba.
Q I'm in the market for a new receiver and I currently own a Harman Kardon. The reason I own an HK is quite simple. I first owned a Onkyo
receiver that was rated at 100wpc. However, when I had it hooked up to
not-so-efficient speakers, it began to clip. I later found out that the
Onkyo receiver only had about 20-25 amps of current. I then switched to a
lower HK receiver that only was rated at 85wpc. Since then, my Infinity
Kappas have sounded fine. I came to find out that HK receivers usually have
high current - some as high as 70 amps. My question has two
parts.
1) Being that amplifiers are called "amplifiers" and not "wattifiers", why
don't manufacturers state amps of current when mentioning wattage?
2) Do you know of any other high current receivers that I should take a
look at?
A It's all in the power supply. Most receivers are rated at their limits. This has come about over the years due to price point and specsmanship. If the receiver amplifier will deliver 105 watts/channel into 8 Ohms, it will be rated at 100 rather than a more conservative 85 watts. Also, the output rating can be made from 20 Hz - 20 kHz, or at one frequency, say 1 kHz. So, you have to look closely at the specification sheet. The HK is rated more conservatively, and also probably has a power supply that will deliver much more during transients. The term "high Current" is used to imply that the amplifier will deliver considerable power into low impedance loads, say 2 Ohms, rather than meaning it will deliver high power into 8 Ohm loads. Just check the spec sheets of any receiver you are considering, to make sure that the rating of power is full spectrum rather than one frequency, and if it is rated into 4 Ohms at close to twice the power as it is into 8 Ohms.
Q I'm interested in a 6 head VCR, and I have a satellite dish. How good will the picture quailty be when I record ? Is it worth the investment and why?
A Multiple heads on VCRs are used for recording at different speeds. The best images will be obtained using the fastest speed. Tapes recorded at the slow speed deteriorate quickly and become unusable. I would suggest, however, getting a VCR with what's called a "Flying Erase Head". The erase head is on the same drum as the recording head, and this will give you clean breaks between recordings (the stop of one recording and the beginning of the next). Otherwise, you end up with colored streaks that run up and down the screen for a few seconds at the beginning of each new recording when a recording has been on the previous section of the tape. This is caused by an incompletely erased signal that exists on the tape between a regular erase head (non-flying type) and the recording head.
Q I have a question to ask about
rear speaker placement for surround sound in Dolby Digital. I
learned that in Pro Logic Mode, a dipole speaker is the best and should be
placed 6 feet on the side of listening area. However, in digital surround, where the surround sound is produced full range, which full range speaker or bipole/direct radiating speaker is recommended? In your opinion, what is the best placemant for the rear speakers in a Dolby Digital setup?
A With regular surround sound, such as Pro Logic, the rear is mono rather than stereo between the two speakers, and limited bandwidth. A diffuse sound is intended, so dipolar and bipolar speakers are often used because they produce a more diffuse sound than monopoles. With digital surround sound technologies, such as Dolby Digital (AC-3) and DTS, the sound from the rear is not diffuse. It is full range and is generally used for very directional effects. So, monopoles are usually the best, if you like your sound focused. However, if you like a diffuse soundstage, you can still use dipoles or bipoles in the rear, and in the front too for that matter. It really depends on the type of sound that you like. One of the best home theater setups I saw at the Hi-Fi '97 show in San Francisco, used dipolar speakers (electrostatics) for five channels of the 5.1 channels in DTS. The only really necessary change, IMHO, for digital surround, is the use of full range speakers in all channels (except the LFE), rather than changing from dipoles to monopoles. Generally speaking, floor standing speakers will give better response below 70 Hz than bookshelf speakers.
Q I am planning to set up a home theater system which also has to be able to deliver good music listening. I understand that most AV receivers do not have good amp performance, and I am considering using separate components. My budget is limited, and I have two options:
1. Buy a decent AV receiver like that Yamaha RX-V592 (similar to the
RX-V990 you recommended but at lower power) which has full 5.1 channels
pre-in/out and upgrade it with a good 5 channel amp such as the Rotel RB-985
that was eatured in your review.
2. Buy a good two channel amp first (Rotel RA-970 or Marantz PM-57) and then
add a three channel amp/decoder such as Yamaha DSP-E492 to drive the center
and surrounds. DSP-E492 also has a 5.1 channel in/out allowed for future
expansion.
Both options here would allow my future expansion needs. I am concerned
about which option will give the most balanced sound and ease of use. I hope
you can advise me on that, or to recommend any other options.
A I would suggest the first choice. The on-board amp will suffice for now, and the RB-985 delivers 100 watts per channel, as well as being THX certified. The Rotel RA-970 only gives 60 watts per channel, which is about where the RX-V592 is to begin with. The DSP-E492 does not have the flexibility that the 592 has, and using one brand of amplifier to supply the center and rear speakers, while another brand supplies the front left/right, would not be such a great idea. The center channel, in fact, is the most demanding, and the E492 would not give you very satisfactory results, especially if you eventually add an outboard AC-3 decoder.
Q You have referred to something called Xmax in articles about speakers. What does this mean?
A Basic Xmax is the maximum distance that the voice coil can move in one direction (towards the front of the driver or towards the rear), and keep a constant number of voice coil turns (of wire) in the gap of the permanent magnet. Click here to see diagram. Xmax in this case is the distance that the voice coil moves until one of the four red turns of wire on the coil is out of the magnet gap. The coil can move farther, but the motor strength decreases. The actual calculated Xmax is voice coil length, minus the air gap height, and divided by 2. So, you can end up with the same calculated Xmax using different gap height and voice coil length. Such varying combinations produce speakers with different characteristics.
� Copyright 1997
Secrets of Home Theater & High Fidelity
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