|
|
|
Q There
are several speakers on the market now that have THX certification.
I have read that these speakers have to conform to some
dispersion parameters that mainly limit reflections off the wall.
First of all, how does this help sound quality? Secondly, if one
were to buy a
speaker primarily for music reproduction, is a THX certified speaker
preferable over a non-certified speaker?
A Speakers
designed specifically for home theater have dispersion patterns
designed for viewing and listening by several people rather than
one person sitting in the "sweet spot". Specifically,
they limit vertical dispersion to reduce the amount of sound hitting
the ceiling and floor, and give more dispersion sideways due to
the assumption that a family is watching a movie. This does make
a difference in the overall sound pattern, and some people don't
like it when listening to music. Even if you were going to buy
speakers just for home theater rather than music, you should still
audition them to make sure you like the effect that they provide.
The "preference" you speak of really has to be your
own.
Q I
have seen S/PDIF connections referred to. What are they?
A S/PDIF
means Sony/Philips Digital Interface, and they are used for digital
transmission between one component and another. On the rear panel
of CD transports, laserdisc players, DVD players, and receivers
with digital decoders built-in, will be found S/PDIF connectors.
S/PDIF connectors are unbalanced coaxial or optical, and the specified
(required for proper transmission) impedance is 75 Ohms (the optical
ports are terminated with 75 Ohm resistors). They are often in
the form of RCA jacks, and that is unfortunate, because RCA jacks
make lousy digital connectors (except under specifically designed
conditions) due to improper impedance (most are around 25 Ohms).
They should be 75 Ohms. Otherwise, the high frequencies reflect
back into the cable (the digital bitstream is a radio frequency
signal). The best digital connectors are 75 Ohm BNC connectors,
but because cables with BNC plugs are not as readily available
as cables with RCA plugs, we end up with poor quality digital
transmission between our transports and DACs. A high quality 75
Ohm BNC jack is about $3 retail, and probably $1 or less at wholesale
in large quantities, so CD player manufacturers certainly could
put the proper connectors on their products. A bad connection
between the transport and DAC can be a source of jitter, and would
result in harsh sound.
Q I
understand that the newer DVD players have DTS bitstream bypass
and If I have a DTS decoder, I can hear the sound. The question
is what about the video from the DTS DVD? Will a DVD player knows
how to read the video compression from a DTS DVD?
A It
is only the audio that is in DTS. The video is in the same format
(MPEG-2) regardless of the audio (MPEG-Layer 2, DD or DTS). The
amount of video compression may vary from movie to movie, but
your player should be able to decode it all.
Q I
was thinking about adding a subwoofer to my rear channels to beef
up the "umph" factor a tad more. Since my Denon AVM-3600
has a 80 Hz high pass filter that is always engaged for the rear
channels, would it really be worthwhile to add a sub to the surround
channels? What are my options as far as adding a second sub to
my setup?
A The
80 Hz filter would take out the bass that you want for your rear
channel subwoofer. One option in this case is just to split the
subwoofer output jack (line level) with a Y connector and run
one leg to one subwoofer and the other leg to the second subwoofer.
This would give you mono subwoofer sound, with two subs. A second
option would be to use the left front pre-out jack to drive one
subwoofer and the right front pre-out jack to drive the second
subwoofer. This second option would give you stereo subwoofers,
and is the one I would choose. You will have to steer the low
frequencies from the other channels into the front left/right
so that the bass from all channels will reach the subwoofers.
In either case, you will need to experiment with the best placement
for the two subs, as well as the phase switch settings.
Q I
currently have Rotel amps powering my Maggies (Magnepan 3.5s).
For the L/R speakers, I have a two-channel amp @ 100 watts/ch
and for the center and surrounds, I have their six-channel amp
that is bridged to give 90 watts/ch. I've heard that bi-wiring
can improve the sound of the Maggies and so am considering adding
the Rotel 991 ($999) providing 200 watts/ch. Would it make more
sense to upgrade by replacing the current amp and using it elsewhere
(bridging it for the center channel to give 200watts/ch) or bi-wiring
the main Maggies? If I do bi-wire, which amp should go to the
treble/midrange and which to the bass (via the x-over for the
Maggies) or does it make a difference? Lastly, would upgrading
the amp or bi-wiring be worthwile, or should I save the money
and buy a five channel amp later? (I'd rather not spend $3-5,000
on a new amp if I can more reasonably "upgrade" the
sound for around a grand instead.) I do not want to change to
a different make amp for the mains only since I've heard that
sonic matching should be maintained for all five channels.
A Bi-wiring
means using one amplifier with two sets of speaker cables. One
set of cables goes to the tweeter/mid-range, and the other set
goes to the woofer, with the connecting bus bars removed (usually
a pair of flat metal plates that connect the woofer and tweeter/midrange
speaker binding posts together). Bi-amping, which is what I think
you are actually referring to, means one amplifier powers the
tweeter/midrange, and another amplifier powers the woofer, again,
with the bus bars removed. Bridging the Rotels for use with Magnepans
is not a good idea since the Magnepans are 4 Ohms nominal impedance.
Bridging an amplifier results in doubling the minimum impedance
that the amplifiers can drive. Typical amplifiers are rated into
4 Ohms minimum. So, usually, this means sticking to 8 Ohm speakers
when bridging the amplifier. Neither of your present amplifiers
is sufficient for driving Magnepans to high levels, since not
only are they 4 Ohm speakers, but they are not very sensitive.
My suggestion is to get a three-channel, 200 watt/channel power
amplifier, such as the Adcom 5503 ($1,300) to drive the front
left/center/right channels, and use your present two-channel,
100 watt/channel amplifier to drive the rear speakers. Save the
six channel amplifier for some other project (you could use it
to drive front effects channels, or perhaps, speakers in another
room). Later on, you might want to upgrade the rear amplifier
by going with the Adcom 5500 (two channels, 200 watts/channel).
Don't worry about mixing brands right now. It won't cause you
any problems.
Q I
like your suggestion of 12 May to wait for digital VCRs instead
of purchasing an S-VHS VCR at the present time. My concern is
that digital TV doesn't seem to be on track regarding the Fall
timeline, otherwise, we would be hearing more from the networks,
manufacturers, and the A/V magazines. I have also only seen the
Sony digital VCR advertised for a mere $4000! Will the digital
VCRs be able to play VHS tapes and how long before the digital
TV revolution really gets going?
A W-VHS
has been around a few years, and this is a Japanse JVC VHS machine
that retails for a mere $10,000! RCA will be introducing a VHS
deck that can tape the digital bits from DSS, but you must play
it back through your DSS receiver to watch it. Of course this
will require a DSS receiver that can link to your VHS deck. The
real problem (in my opinion) is not that they can't produce the
technology, but rather, it's the copyright issue. (Digital camcorders
are available now for less than $2,000, and they are basically
VCRs with a camera and microphone.) Music and movie producers
are very cautious about digital copying, since the copies are
"perfect" (unlike analog where the copy is degraded
from the original). I would rather that they spent the money used
to develop copyright technology on chasing and prosecuting the
pirates instead, and leave the music and video alone so that we
don't have problems with some of the decoders, but that won't
happen. It would be nice to have DVD recorders that would record
96/24 audio, 44.1/16 audio, NTSC video, and HDTV video. Leaving
out 5.1 channel audio recording capability (digital blocking)
might dissuade movie copying. DVD recording would be better than
digital tape (both use compressed video) because the DVD would
never deteriorate. Digital tape should retain the signal longer
than analog video tape, but still, eventually the digital signal
(magnetized metal particles on the tape) will be reduced. I have
some family VHS home videos that I want to archive for my grandchildren.
I doubt if digital VCRs will routinely be able to record and play
regular VHS.
HDTV does seem to have stalled in its scheduled
Fall release, but I don't think it should be much later than the
beginning of 1999. I know the HDTV receivers are ready. It is
the TV stations that are hesitating because of the incredible
expense involved (cameras, editing electronics, transmitters),
and not very many people will have HDTVs for a while. Nor will
there be much programming. TV stations get their revenues from
advertisers, and the advertisers have a hard time justifying big
buck HDTV ads for only a few viewers. From our survey results,
a significant percentage of you (including most of us on the staff
of Secrets) will be getting an HDTV when they become available.
I would be content to use it mostly for watching DVD movies in
progressive scan while the TV stations get their act together.
An occasional sports event or other broadcast program in HDTV
would be good enough for now.
Q I'm tinkering with my system to try to improve the sound on CDs. I have Parasound's C/CD 1500 CD changer and 1600 HDCD DAC. At the moment, I'm using an entry level XLO coax cable from the player's coax output to connect to the DAC, and Monster Interlink400 to connect from the DAC to a B&K Reference 20 preamp/processor.
I've been auditioning cables for the DAC-to-preamp
link, and so far I like the Nordost Red Dawns a lot. I also ordered
the ADAM module for the
player, which will allow me to connect to the DAC via balanced
XLR or AT&T glass.
I'm not sure what to do about the player to DAC cable:
1. If I go the XLR route, can I use any interconnect cable with balanced terminations, or should I be looking specifically for a "digital" cable?
2. If I go with the AT&T glass, who makes good cables?
3. Between AT&T glass and XLR, is one
method preferable to another?
A You
will definitely get an improvement going from your coax cable
to either balanced XLR or optical. S/PDIF connections require
either a 75 Ohm unbalanced coax or optical. Most RCA jacks are
not 75 Ohms. Since you like the Red Dawns for analog, have Nordost
make a balanced cable for you to use with the transport-to-DAC
connection. Nordost makes sure the impedance is correct for XLR.
One of the less expensive models will be fine for this, such as
Blue Heaven. Glass is good when you have impedance problems or
ground loops. Otherwise, use the balanced cable. Toslink optical
cables (usually a polymer fiber optic) are commonly available,
but AT&T glass cables are not (at least from the audio cable
manufacturers I checked). I did find that Audio Advisor has AudioQuest
Optilink Pro 1 AT&T Glass Fiber Digital Cables on sale for
70% off list price, which means you can get a 1 meter cable for
$50. It might be a good idea to get one just in case down the
road you want to use the AT&T connectors on your components.
I suspect this type of product is being phased out.
Q I
currently have a Meridian 565 Z3 v4.4, Sunfire Cinema Grand, Krix
Esoterix MkII Front, Krix Centrix Center, Krix Classix Rears,
and a
Velodyne VA-1215X Subwoofer. I have been playing around with Meridian's
setup in configuring my speakers, and I want your opinion on which
you think is the best setup for my system. My current setup is
set as follows:
Krix Esoterix Mk II Tri-wired using voltage output on Sunfire
565 Speaker Layout: AB
565 Subwoofer Settings: Mono, Narrow
If I want to be able to take advantage of
the bass with the Krix, what would be the best speaker setup?
Should I be setting up the sub as Mono or
LFE? Should I be using the Narrow or Wide setting for the sub?
Am I better off using the crossover on the sub or the 565? Is
this the best way to
wire my front LR speakers?
A I
would configure the 565 with the left and right as full range.
Set the bass management control on the speakers based on the table
in the setup manual. You will probably end up using 14 as the
number.
I have always used the sub set for LFE.
This changes the crossover from 80 Hz to 120 Hz, and I leave it
on the narrow setting. The crossover in the 565 is much better
than the one in your sub, so you should use it.