Q&A # 35 - October 28, 1997
Staff
Q I recently bought a receiver with AC-3 built in, and I want to add DTS. The receiver has pre-out jacks but no pre-in jacks. You mentioned something about having DTS decoders installed inside the receiver as an upgrade. I don't know if I really want to do this. Are there any other options?
A Yes. Some of the DTS decoders have the ability to send 5.1 signals through when not using the DTS capabilities. So, with the Millennium DTS decoder for example, you could connect the pre-outs on your receiver to the 5.1 inputs on the Millennium, and the 5.1 ouputs from the Millenium to an outboard 5-channel power amplifier and a subwoofer. When using Pro Logic or AC-3 (Dolby Digital or DD), the Millennium will pass the decoded signals through to the outboard power amplifier, and when playing DTS signals, you use the volume control on the Millennium rather than the receiver. Of course, this means you would need an outboard 5-channel power amplifier, so if you really like the 1-box solution that receivers offer, your best bet would be to have the DTS decoder installed in your receiver. This way, the volume and channel balance controls of the receiver will operate for all types of signals, and you won't have to get any additional amplifiers.
Q Hi,I just got hooked onto your sight and boy is it interesting. You
seemed to have knocked all the main points straight over the head and
that I'm thankful for. But I do have some questions for you.
1. What kind of speaker can you recommend that I can use without the
purchase of an extra subwoofer? I'm willing to spend at least 2000
dollars. My room is about 14' x 13'. My listening preference is
50/50 both music and movies.
2. I'm stumped between the Pioneer E06 THX A/V Amp and the Harman Kardon
AVR-80 THX amp (if I haven't gotten the letters mixed-up). Which can you
recommend for good bass output and reserve power? Or maybe you can recommend something else which you think is better.
3.Do you think a speaker that can play down to 30 Hz is recommendable in a room of my size?
A After testing a number of subwoofers, I am convinced that no full range speaker is really capable of doing what a top notch dedicated subwoofer can, namely reproducing frequencies in the 20 Hz - 30 Hz range in a relatively flat manner. However, there are plenty of speakers that can do a good job down to about 30 Hz. From what you have told me, I would suggest auditioning the Eminent Technology LFT-VIII [click here to see review in Secrets]. They are large speakers that will give you excellent sound staging, potent bass, and great home theater. If you are really after powerful bass, then you will need to either consider a separate high quality subwoofer, or plan on something different than a receiver amplifier. Receivers don't really have big power supplies, so an outboard amplifier connected to the receiver pre-out jacks will be necessary. The Sunfire CinemaGrand is a killer. For less money but still remarkable power and quality, the Carver AV-705x is great, as well as the Adcom GFA-7000. Your room size is fine for 30 Hz.
Q Thanks a million for replying to my question in a previous Q&A.
After auditioning with your recommendations, I realize that bi-amping with the Adcoms doesn't sound as sweet as using one amp by itself. Bi-amping causes the highs to be quite harsh and forward sounding. Soundstaging did improve, but only slightly. Also the bass seems to reduce in depth. I had an Aragon to compare at the same time. The Aragon's soundstaging is very good. There is a lot of warmth in the
midrange for vocals, and the overall sound was very relaxing. The highs were not crystal clear, but they were very accurate. During the audition, I was using the VTL2.5 pre-amp, and the overall sound was quite heavy, but the bass did go down really low. Whan I tried it back home with my Golden Tube SEP1, there was a loss of depth in the bass region. The highs and midrange sounded much cleaner and warm. Also the output volume was quite low (I had to turn it up to the 12 o'clock
position), and I had to change the volume control jumpers inside the SEP1 to "high rating mode". I am still trying to improve the bass region. I tried
bi-wiring with my Midnight 2, but that caused the overall sound to become a bit loose. I was wondering if MIT Terminator 2 cables would increase the bass. It is not that there isn't any bass, but I would like more bass when
listening to jazz and new-age music. I have no complaints when playing
vocals and light music (piano recordings). In fact, on these playbacks, the vocals really sounded airy, and I could feel the warmth inside the words. Soundstaging and presence for music was also good. What do you think is the missing link? Thanks again.
A First, let me compliment you on your meticulous approach to auditioning. If the Aragon still left you wanting bass, then I suspect the problem may be in the CD transport, or perhaps the speakers. In general, I have not found cables to make as much difference with the bass as they do with mid-range and treble. However, I have heard big differences with CD transports and DACs. This is not necessarily a criticism of any CD players or speakers, but merely that there are "personality" differences in these components, more so with speakers, of course, than with CD players. The McCormack CD package that we use (see reference component section) has bass as deep as we have ever heard in a transport/DAC combination. So, I would suggest auditioning some CD players, and maybe even a subwoofer. Tube components are notorious for not having really powerful bass. We solved this problem with a Class A Single Ended Triode preamp and power amp combination by adding two subwoofers. The result was incredible. One listener thought we were having an earthquaqe while playing an Enya album. Anyway, let us know how your search proceeds.
Q Hi! I'm thinking of getting a 48" rear projection TV. My room's dimensions
are roughly 11 feet by 11 feet. What is the "appropriate" distance that I
should place my viewing seat from the TV screen? Can you give me a yardstick to measure the suitable viewing distances for different screen sizes?
A Start with 3 - 5 times the screen height, and end up with whatever is comfortable. I find that depending on the aspect ratio (width of image divided by height), i.e., whether it is a widescreen movie or not, I move my chair closer or farther back. I used to watch "Ben Hur" in widescreen format, on a 60" rear projector TV, with my feet resting on the base of the TV. Sometimes I am in the mood to sit close regardless of the movie, and sometimes back against the wall. Obviously, this works better with an easy chair than it does with a couch.
Q Quick question: can dipolar speakers be used when listening to movies
or music encoded in DTS, or is it best to use regular speakers for the
surrounds?
A Dipolar speakers can be used with any format you wish. It is a matter of your preferences in sound that really count. Monopolar speakers have the most focused sound, while bipolar speakers are more diffuse, and dipolar even more diffuse than bipolar (dipoles have more cancelation at the sides than bipoles). For movies, dipoles and bipoles can produce remarkable home theater, whether it is Pro Logic, DD (AC-3), or DTS. My set of Carver Mark IV Platinum dipole speakers are so astonishing (to me) with movies, I will never get rid of them. Again though, it depends on preferences. Some people do not like the dipolar sound.
Q I have seen a lot of comments in several magazines stating that DTS
sound is slightly but clearly superior to AC-3 Dolby Digital, and also
that shortly we will see DVDs with DTS. I have a Sony DVD Player. Will
it be possible to listen the sound of the DVDs with DTS?
A A few months ago, it appeared that we might be able to use our current DVD players to watch DTS DVD movies. Now, it looks like we may need a different DVD player to handle these discs. There may also be a glitch with the DTS decoding of the bitstream from DVDs, so we may possibly even need to upgrade the current DTS decoders. If that is true, I think DTS DVDs may be in for some marketing trouble. But, the final verdict on this is not in yet.
Q I was just wondering how much a Hi-Fi VCR will affect my surround sound and
clarity on my home theatre compared to a regular non-Hi-Fi VCR. I have a
Yamaha 692 amp, and it sounds good, but my friend said that a Hi-Fi VCR will make it sound a lot better. Is that true?
A The better quality VCRs record and play the audio with a diagonal track from the spinning head that also records and plays the video. Even the slow speed tape recording and playback gives good audio results. At all speeds, the audio is better on "Hi-Fi" VCRs than from the stationary audio record/playback heads on regular VCRs, but the Pro Logic effect will probably not be any different. Rather, the clarity would be improved (and lower noise level) with the Hi-Fi VCR head.
Q I am looking for some technical assistance based on experience with Dolby
Pro Logic. I have recently built my own home theatre system and am using the Dolby decoder chip. All seems to work very well. The only question is that there is always some audio in the surround channel (albeit very low) when there is say, just speech, i.e., no ambience effect expected. Is this normal breakthrough, deliberately done when mixed, or do I have a problem?
A Noise (hiss and buzzing) from the rear surround with Pro Logic is normal. Some decoders have more than others, but they all have it to some degree. It is an artifact from the decoding process. Also, with Pro Logic, it is normal to have some audio in the front left/right and the rear surround, even when there is only supposed to be sound in the center. This varies quite a bit on the decoder, but even the best of them seem to have a little of it. Again, it is an artifact that is produced by the fact that there is finite time between the point that a signal enters the decoding chip and when it is decoded. Since the decoding process is a tiny amount of time behind the signal entering, some signal is left over and escapes into the overall output to the other channels. DD and DTS don't have this problem.
Q Thanks for your previous answer to my question. I just found out that the store that carries REL Subwoofers, also carries Sunfire. I had a chance to listen to both. I found the Sunfire to be very powerful, and I like it a lot. Could you recommend the setting for the Sunfire to be used for small speakers like Coda 7 and a small amp, the Yamaha DSP-A592 (70 watts rms)? The rating of Coda 7 is 48Hz to 20KHz, so in order to achieve deep accuracy bass without sounding boomy what is the best cut off frequency? I am thinking about 60Hz, is it Ok?
A I would suggest about 50 Hz as the low pass cutoff. Also, you want to make sure the volume control on the Sunfire is not set too high (of course, there is always the tendency to turn it up when you first get it home because it is so powerful and clean. But after the novelty wears off a bit, turn it down.) The Sunfire is designed to go in a corner. However, since your other speakers are small, you should experiment with the subwoofer location. It might work better for you if it is out approximately 1 foot or so from the main wall. Put on some classical music or jazz with good bass and have a friend adjust the phase knob first, then the volume while you are in the listening position.
� Copyright 1997
Secrets of Home Theater & High Fidelity
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