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W2IHY 8 BAND AUDIO
EQUALIZER
and NOISE GATE
by
Bob Hutchinson, N5CNN
Zero, as in zilch, none,
nothing, are good words to describe my level of knowledge about audio equalizers, studio
audio gear, studio microphones and associated equipment. Well, I have
heard of some of the prices for such equipment - wallet smashing stuff.
If
I have no knowledge of this equipment, I know some Hams are as
knowledgeable as me so this review will provide some insights into the
benefits of improved transmitted audio. You and I will be better informed
about audio equalizers and this W2IHY 8 band model with noise gate.
This equalizer was designed
from the beginning for Ham Radio use. It is specifically for Icom, Kenwood
and Yaesu transceivers and has a three position selector for the three
types.
Upon opening the package I
noticed the apparent quality of the unit. It had a Kenwood microphone out
adapter to plug into the TS-570D transceiver for the review. A nice 117
VAC wall power supply was included with the proper five pin DIN male plug
to supply 12 V power to the unit. Of course, there is the operation
manual, which, because of my knowledge level, will be read first.
Information
from the first page of the manual:
"Analog and digital technology have for many years been used in the audio
industry to do audio equalization and noise reduction. Many amateurs have
purchased audio equalizers and other equipment with the hope of improving
their transmitted audio signal. Those that have succeeded have in many
cases had to pay premium prices for audio equipment that not only required
modification to properly interface with their amateur station but also had
to be hardened to tolerate RF."
Hook up
After reading the manual, . . . well, most of it, hook up was easy.
The microphone used initially is a Shure high impedance dynamic cartridge in an
antique head mounted on a custom swing arm boom, was plugged into the MIC
IN with the 8 pin female plug. The Kenwood adapter, furnished with the
unit was plugged into the MIC OUT A and the MIC OUT SEL switch was set to
A. Since I an using a high impedance mic I set the MIC IMPEDANCE JUMPER to
"no jumper" as indicated in the manual. No mic power or voltage
required for this Shure mic so I left
the MIC IN POWER jumper at default of "no jumper".
After turning on
the power, the MIC IN and MIC OUT pots were set. Good manual instructions for MIC IN and I clock-wised it until red LED
came on during normal speech and counter-clock-wised it until the LED did
not come on during normal speech. Instructions were not specific about MIC
OUT so I set it to for normal VOX operation with mouth 2 inches from the
mic.
In handling the EQ unit and
its controls, I continued to be impressed with the physical quality of
this equipment, which cost only $229.99 plus $15.00 for the mic out
adapter.
The noise gate was set just
like in the manual. All hooked up and it works. I turned the station antenna
switch remote to connect the transceiver to the Palstar dummy load and
started testing: "Hellooooo Radio, test VOX, one, two, three four, test
VOX, one, two, three four, test VOX, test VOX, etc." I found and felt comfortable after reducing
the VOX gain from 7 to 5 and the mic gain from 65 to 50. Delay set at 5ms.
Headphones for
adjustment
The manual says plug the
headphones into the unit to be able to hear the results of noise gate and
EQ adjustments. (Notice I'm using the jargon?) The headphones let me hear
the adjustments but manual says one should get on-the-air feedback or
provide a way to record, perhaps through another transceiver, and playback
to hear the real effect. Perhaps I could put the headphones on someone
else for their suggestions or critique.
There are two stations here
at WIA. The main station has all the coax, antenna switches and remote
control stuff. The remote station, where this test is taking place, is to
my left at my U-shaped work area. When I turn on the 13.8 power supply
here, control of the main station and the antenna switch is transferred to
this station.
I have little background
noise, so the noise gate won't help me as much as it will someone with a
high ambient noise situation at their station. The Kenwood transceiver has
a monitor feature with adjustable volume but this monitor sound is not
transmitted sound and is useless for our purpose of EQ adjustment.
I found a table in the
manual that provides initial settings for popular microphones and selected
settings for Shure high impedance dynamic mic. Initial on-the-air test indicates
that I sounded normal to the guys. This was with little adjustment
from zero. Now for more test.
Further on-the-air produced
comments like. "Wow, what a big difference." " Big improvement in quality
of sound, it's warm and robust." Every day I experiment with different
adjustments and get feedback. I feel like the noise gate is improving my
transmitted signal more than I know even though I don't think I have a
background sound problem. I now have the unit standing on it's end between
the Kenwood and the antenna switch remote control. It takes little space.
Equalization Overview
(From
the W2IHY web site)
Everyone is familiar with the simple tone control on broadcast receivers
and stereo equipment. As consumer electronics technology advanced, the
general public was introduced to a more sophisticated tone control, the
graphic equalizer. It is called a graphic equalizer because the physical
position of the slide pots gives a graphical view of what is happening
electrically. You will be using the W2IHY graphic equalizer to increase
(boost) or decrease (cut) the signal level at various frequency values (or
bands). Boosts or cuts are made to suite personal tastes of the user.
Broadcast
engineers and recording studio technicians consider equalization (called
EQ for short) to be one of the most important tools in achieving desired
characteristics in a final audio product. Professionals use the
signal-shaping power of EQ as both a creative tool to give audio a desired
personality and as a corrective tool to overcome frequency response
excesses or deficiencies in equipment such as microphones. Professional
audio technology is now available for amateur radio applications and
amateur radio budgets! Amateurs are using the W2IHY 8 Band Audio Equalizer
and Noise Gate to do more good things with their transmit audio than ever
before.
Combining user input with on-air tests, W2IHY Technologies identified EQ
frequencies that are significant to voice operation in amateur radio. They
are (in Hz) 50, 100, 200, 400, 800, 1600, 2400, 3200. This range gives you
virtually limitless options in shaping and fine-tuning your transmit
audio. Note that you get more finite control than the simple bass and
treble adjustment built into some transceivers. Of course, in this arena
our 8 band model is more sophisticated than our dual band model.
With
smooth-action slide pots, you can boost or cut the individual bandpass
frequencies by +/- 16dB. W2IHY also provides a simple user modification
for operators who wish to set their equalizers to different bandpass
frequencies
For the most critical EQ adjustments, nothing beats listening to your
actual transmit signal on a second receiver in the shack, using good
quality headphones. This lets you get "up close and personal" with how
your transmit audio really sounds. You will notice that very small
adjustments to the slide pots can make meaningful changes. Many of our
users conduct on-air adjustments, relying on friends with good ears. Of
course this is best done under low-noise, high signal conditions.
The operator's manual offers Preliminary Equalizer Settings for a wide
variety of popular radios and microphones in both Rag Chew and DX modes.
This database is growing quickly and we will be adding it to W2IHY.COM in
the future.
Conclusion
Much of the mystery is gone and I'm comfortable with this nice W2IHY
Technology audio equalizer product. The W2IHY is quality product at
a very reasonable price and a wonderful introduction to the audio
equalizer arena and, best of all, this product is designed for the Ham
Radio environment rich in RF utilizing the microphones in everyday use.
It was a snap to setup too. Reports are wonderful and my self esteem is
wonderful too. Now I know I sound good on the air and I have the ability
to adjust my transmitted sound to suit my desire to "sound good". I may
move up to more expensive equipment, but until I do this unit will be a
permanent part of this station and I may buy another for the main WIA
station.
For a lot more information
or to purchase, click through to the W2IHY web:>
http://w2ihy.com W2IHY Technologies is
owned and operated by guess who?
W2IHY,
Julius Jones.
Bob Hutchinson, N5CNN
President and Founder
Wireless Industry Association
713 467-0077
If you would like to
publish an article here contact Bob
Hutchinson, N5CNN.
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