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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.