The sound of clipping
March 31, 2004
How can I tell whether or not my amplifier is clipping if
it does not have clipping indicators? If it is happening, will I be able to hear it or
will it occur at inaudible levels and have already damaged my speakers by the time I am
able to hear it?
John
Very good question. Honestly, both scenarios you've
described are possible -- you may or may not be able to hear instantaneous clipping. I've
found that pushing an amplifier past its limits will typically produce a very hard, bright
sound. I've also witnessed amplifiers that do have clipping indicators that have produced
no audible distortions when the clipping indicator is lighting up like a stoplight.
Clipping distortion will damage speakers, as you noted, so waiting until you hear a
problem isn't the best idea. I think you get a feel for pushing the limitations of your
system over time. But if not, probably the best rule of thumb is to back off the volume
control if you hear the sound change for the worse at a certain loudness level.
Opinion on JVC CD player
March 29, 2004
I'm in the process of upgrading my stereo, which is more
than ten years old. First thing I did was buy a pair of Magnepan MMGs
-- very happy with that choice. I've also read some good things about NAD amps and I'm
going to check them out.
But here's my question. I have an older JVC CD player, and
I'm thinking I don't need to replace it. The specs on it are pretty impressive: S/N 112dB
and THD .0015%.
I know specs don't always translate into good sound, but
since doing a side-by-side comparison might not be the easiest thing to do, I thought I'd
get an idea of what audio reviewers have to say about JVC CD players. JVC marketing
rhetoric says:
"The exclusive JVC P.E.M. D.D. (Pulse Edge Modulation
Differential-Linearity-Errorless D/A) Converter is touted by media reviewers and
audiophiles as one of the most accurate and musical 1-bit D/A converters available. The
delicacy and subtlety of the music can be heard at all levels as it was meant to be."
So, as I said, I'm wondering if audio reviewers have good
things to say, but I can't find any reviews on the Internet. Have any of you guys listened
to JVC's PEMDD Converter? I'd be curious to hear some opinions.
L.D. Winiarczyk
The manufacturer's specifications will tell you
only part of the story. There are receivers from ten years back that have outstanding
technical specifications but sound pretty lousy. Having said that, JVC CD players have
always maintained an excellent reputation. In its day I'm sure your player held its own
quite nicely. Digital technology has improved rapidly through the years, though, and
today's players have more capability and better sound quality than those from just a few
years ago. If you're happy with the JVC, then by all means keep it. But if you are looking
for an upgrade in sound quality you'd be doing yourself an injustice by not listening to a
more modern player, perhaps one with SACD and DVD-A capability. That's the only way you'll
know for sure how the JVC stacks up to you.
New system for Amy
March 23, 2004
I am in the market for a new audio system, and being swayed
by the Denon F101 series, which includes the DCD-F101 and the DRA-F101. I have been
advised to consider teaming the system up with the Athena AS-B1 or Tannoy MX-1M speakers.
I am living in a remote Aboriginal community in Arnhemland, Australia, (difficult to shop
around) and hoping to get some indication as to whether these conponents are a worthy
choice. I am willing to spend around $1500 AU, and this collection fits the mark
financially.
Do you consider this a good buy, or is there a similarly
priced system that I would be a fool to overlook? Would appreciate any thoughts on this
matter.
Amy
The Denons you're looking at appear to be good choices
-- at least on paper. The specs and features are impressive, and being able to buy them as
a package without speakers lets you choose your own, which you're doing. Many companies
won't let you separate out the speakers, so you end up wasting a portion of your budget on
something you won't use.
Both the Athenas and the Tannoys are efficient speakers,
which is an important consideration; the Denon receiver is rated at 35Wpc, which is plenty
of power as long as the speakers don't require tons of power. Your two choices should fit
that power output just fine. As far as I can see, you're on the right track. I'd hope that
you could hear both the Athenas and Tannoys before buying so you know which sounds best to
you, but either way you'll have a high-quality small system that I'm sure you'll enjoy.
Good luck, and let us know how it turns out.
Using an equalizer to increase bass
March 22, 2004
I want to enhance the low-frequency sound produced by my
floorstanding speakers. I was wondering if adding an equalizer of some sort is a good and
relatively inexpensive way to do this.
John Vernon
Well, it would work, but there's no free lunch.
When you add gain (power) in a particular frequency range, you lower the speaker's
power-handling capability because you're feeding it more and more power, albeit in a
narrow band. More power into the bass range will therefore lower the overall
power-handling ability of the driver as it struggles to provide the sound that you're
asking of it -- sound that it's not naturally producing. This also impacts the power
amplifier driving the speaker -- you'll be asking it to deliver more power into the
speaker at the frequency you're boosting. Assuming you have robust speakers and power
amplifier, you can do what you're proposing, but just keep in mind the potential down side
as you drive your components harder. A better solution for more bass would be to add a
powered subwoofer.
Questions on adding an amp
March 19, 2004
I have a NAD T752 receiver (80Wpc). I want to add a used
amp to run my main and center-channel speakers. The NAD has preamp outputs. Can I use a
three-channel amp like a B&K, which has the warm sound like my NAD? The NAD would
power the rear surrounds. Or should I save more money and get a five-channel amp? My
speakers are PSB 5Ts rated at 175W. The center is a PSB 8C rated at 150W and PSB 1B
surrounds rated at 80W. I want to get an amp in the 150Wpc area. I've talked to an NAD
dealer and he said the three-channel amp is not a good idea because of the stress on the
receiver, which would not be using the main and center channels. Please advise.
Glenn
I don't follow your dealer's advice -- adding an
amplifier to drive your front channels will not stress your receiver, but in fact will
remove stress from your receiver. I see nothing wrong with your intended upgrade path. You
may find it easier to add a stereo amplifier to your system just because they are more
plentiful than relatively rare three-channel amps, but again, either scenario is fine.
Your receiver is more than capable of driving your surrounds (and center-channel for that
matter), so I'd be inclined to upgrade the front channels, especially if you listen in
stereo as well as multichannel -- you'd be maximizing this aspect of your system's
performance considerably.
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