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Q Surprisingly,
remote control is not a common feature in high-end audio gear.
Is there any negative effect on the sound quality
caused by the remote control mechanism, probably the jitters from
the motor wheel that turns the volume knob? Are there any apparent
reasons?
A I
think it is probably just that remote controls are more relevant
to mass market products where there are so many features and possibilities,
a remote control becomes necessary to select among them. High
performance products tend not to have so many features. On/off,
input selection, volume, and that's about it. So, a remote control
is superfluous. I've never found any particular problem with remote
control functions and noise though.
Q I
just added a Parasound HCA-2003 amp to my setup and noticed a
humming/buzzing coming from the speakers when I turn the amp on.
The amp's manual states it may be necessary to "lift"
the ground to reduce hum by using an AC plug adaptor to lift the
the ground. I did this and it
eliminated the hum but I am concerned if this is a good way, sound
wise and safety wise, to eliminate the problem. I have read that
Mondial makes a $99 ground isolator that is suppose to eliminate
the problem. Any opinions on the Mondial Magic Box or any other
such product? What is this hum anyway and what are your reccomendations
for eliminating it?
A You
are experiencing a ground loop. This occurs when the ground potential
(voltage) for one component is different than another in a system
where various components are connected together. Current travels
along the ground wire in the audio cables and therefore gets into
the sound as a 60 Hz or 50 Hz hum, as well as any noise that is
in the AC ground. It can happen when two components are plugged
into two different AC wall outlets, but one of the most common
sources is from the TV cable connection. The Mondial product is
for the TV cable problem and is connected between the cable outlet
in the wall and the TV. It uses a transformer to isolate the cable
ground from the TV. Removing the ground prong from three-pronged
AC plugs is a way of getting around ground loop problems, and
it works with many components. The ground, for the most part,
is a safety measure, but some components require it for proper
functioning. If your Parasound instruction manual says it is OK
to take it out of the connection for that particular product,
you should have no problems in doing so.
Q At
night, I like to listen to my receiver at low volume. Something
I can fall asleep to. I have a Yamaha A-3090 receiver and Yamaha
speakers. I know that playing music at a loud setting could cause
clipping, but what about listing at a very low setting? Is this
damaging the receiver and speakers by running the system under
very low volume conditions?
A Your
receiver will just coast along with no problems at low volume.
It might be wasting a little more energy in heat, relative to
the low volume, but a warm room will just make you fall asleep
faster.
Q Can
you tell me if there are any potential problems or drawbacks with
the configuration I have presently set up? I am using an ATI-1506
amplifier with Vonschweikert home theater speakers rated at 8
Ohms on 5 channels and use the HSU research TN225HO Sub on one
other channel. The HSU sub is rated at 4 Ohms. The HSU is sharing
the same supply from the ATI with the center channel speaker.
As you might know the 1506 shares the same supply per pairs of
channels.
A Because
the center channel gets most of the sound, I would suggest changing
the configuration so that your subwoofer is sharing the power
supply with one of the rear channel amplifiers.
Q It
seems likely that there is DD in my future. Renting a DVD player
and playing a few movies through my Pro Logic setup convinced
me. I just wonder how to handle the LFE channel. My mains are
NHT 3.3s and routing the LFE signal to them would be best? Would
this be possible with a DSP-A1 processor/amplifier? Also, does
the DSP-A1 have a dynamic compression circuit? Some movies are
a bit out of control!
A Routing
the LFE to the front left/right would work fine. Adjust the LFE
output so that it does not overpower the NHT 3.3s, especially
since most movies right now just duplicate low frequencies from
the other channels onto the LFE. The DSP-A1 allows you to do this,
as well as adjust dynamic compression. Later on, you should add
a good subwoofer which will take you into the netherworld of 20
Hz.
Q I
am thinking of purchasing a speaker kit which contains schematics
for a passive crossover. Instead of assembling the crossover,
I was thinking of substituting an electronic crossover because
I was always under the impression that an electronic crossover
(with the required
bi-amplification) always produced better sound than a passive
crossover. However, I was talking to a high-end amp manufacturer
who claimed that an electronic crossover could produce worse sound,
particularly with a very good amp that was very revealing. Is
this true? Also, what is passive bi- amplification?
A Using
an electronic (active) crossover between the preamplifier and
power amplifiers, if done properly, will give you a better sound
than passive crossovers between the power amplifiers and speaker
drivers because the power amplifiers are not wasting energy (and
creating distortion) at frequencies that the speaker isn't reproducing.
However, active crossover use is not simple. You need very specific
and exact crossover frequency settings. If you have three-way
speakers, you need an active crossover that provides high pass
for the tweeter, low pass for the woofer, and a band pass for
the midrange speaker. Something like the Marchand
Electronics two or three way stereo electronic crossover would
work very well for a project like this.
Q I
read (and am still digesting) your article on ported speakers
and have the following question. I have to place my speakers in
a home
entertainment center where the speakers would be enclosed on every
side except the front (the space is 25"H x 17.5"W x
30"D. I have always assumed that a sealed speaker, with no
rear ports or rear firing drivers would be the only type of speaker
enclosure which would work in such a space. However, a local high-end
dealer claims that a rear ported or rear firing speaker in this
enclosure would take on the characteristics of a larger speaker,
i.e., the enclosure would become part of the speaker, and thus
a ported or rear firing speaker would work well. While I find
this
difficult to believe, is the dealer correct?
A Putting
speakers in entertainment centers is tricky because you get bass
loading and diffraction problems from the vertical surfaces next
to the speaker opening. However, if you are going to put speakers
in such a center, rear ports or rear drivers could be completely
blocked, ruining the speaker's designed performance characteristics.
Sealed enclosures, and possibly front ported, will work the best.
Q I
plan to use my audio speakers (Royd Minstrels) as left and right
fronts for Home Theatre. My concern is that they have a fairly
low
sensitivity rating of 87. Most centre channels I've seen appear
to be rated in the 89 - 91 range. My question is would a 91 rated
centre placed
with the 87 fronts create a volume mis-match, i.e., given that
the amp would be providing the same strength of signal to each
speaker, would the
mis-matched sensitivity cause the volume from the Centre to "drown
out" the sound from the fronts?
A Actually,
you should not experience any problem at all, and in fact, it
may be an advantage, since the center channel gets most of the
signal. This will allow you to turn the volume control down on
the center channel to balance with the other channels, and thus,
conserve amplifier energy. The only concern is tonality match
of the center to the other speakers, which is not a function of
the sensitivity. If you mix brands, you might run into this problem,
but otherwise, you should be fine with the higher sensitivity
center.