- Category: Ham Radio
- Created: Saturday, 10 July 2021 16:39
- Last Updated: Saturday, 10 July 2021 18:09
- Written by Rick Swenton
- Hits: 37
This article intended to be more of a philosophical discussion than a technical review. When you are dealing with Ham Radio transmitters and receivers, your choice of microphone can be based on science or opinion or both. There's no real right or wrong answer. It's kind of like asking someone how to adjust bass and treble controls on a music system. Let's start with some technical background.
The Electro-Voice RE27 N/D is a professional grade studio/broadcast microphone. Some of its features include a powerful neodymium magnet and a reinforced diaphragm dome. This offers increased sensitivity (up to 6-dB more output), undistorted output at high sound pressure levels and an extended high-frequency response. The mic has a 5 kHz presence rise. This gives the sound extra clarity. Some people say you can just do that with an equalizer. Sure, you can. But there's something to be said about having that already present in the mic signal. It is a large diaphragm cardioid dynamic mic. It's sound fidelity rivals the best condenser mics. Unlike condenser mics, the RE27 does not suffer distortion from close-talking nor does it suffer from the "proximity effect." The proximity effect is a change in the sound caused by the closeness of the person's voice to the mic. The proximity effect will cause a bassier sounding voice if the person close-talks the mic. Some radio personalities use this effect as a feature sound in their shows. The RE27 maintains consistent quality independent of distance between the person and the mic. Also unlike condenser mics, the RE27 has better off-axis sensitivity. It has a hum-bucking coil. This helps filter elecromagnetic interference and can be especially helpful in transmitting environments.
The RE27 has three with switches near the base of the mic to control frequency response. With all switches off (switched up towards the head) the response is set to flat from 80-2,000 Hz with a 6-dB rise in response from 2,000-16,000 Hz. With one filter switch in the “roll-off” position (down), low-frequency response tilts down 6 dB from 250to 100 Hz. A second filter switch, when in the “roll-off” position (down), creates a gentle roll-off of 12 dB from 1,000 to 100 Hz. The third filter switch, when in the “roll-off” position (down) reduces the high-frequency rise by 3 dB.
The mic has a built-in blast and wind filter and a built-in shock mount. It is unclear how effective these are. I suspect they are better than nothing but not perfect. I have seen applications that have external pop filters but have never seen foam wind screens on this mic. My own application uses the Electro-Voice 309A shock mount suspension. The mic has a balanced 150 ohm output through a standard XLR connector,
This mic is expensive. It lists for $499 almost everywhere. Used ones are typically found between $400 and $450. It comes with a carrying case and a stand clamp. The mic is large and heavy, It weighs a little over 3 pounds.
Now, on to the philosophical discussion. A lot of my "opinions" are formed by two great veteran ham radio operators. One is Clark, N1BCG, who is a long-time broadcast engineer and Ham Radio AM expert. The other is Rob, W1AEX, who is a long-time Ham Radio AM expert and online resource. Both have been invaluable consultants and trusted advisors.
It is my belief that you should strive to have the finest possible audio quality to send to your transmitter. The problem arises when different transmitters and receivers have different capabilities. Modern transceivers from companies like Kenwood, Icom and Yaesu deliberately restrict their transmit bandwidths. Sometimes, this limit could be as low as 2.9 kHz. This creates courteous "good-neighbor" signals on the band. They are spectrum efficient and generally non-interfering if the audio is adjusted properly. Some hams use ancient relics for receivers and transmitters, There is a lot of equipment still being used today that was originally placed in service during World War II. Much of this unmodified equipment will not have high fidelity receivers or will not be capable of full fidelity transmit. Most of these users will not be able to tell the difference between your RE27 mic and almost any good basic mic. Even the factory hand mic on the Icom IC-7300 sounds great to most people. Why would you spend the money on a mic like the RE27 if most people won't notice?
It is my belief that you should strive to have the finest possible audio quality to send to your transmitter. My main transceiver is the Apache Labs ANAN-7000DLE MKII. It is a software defined transceiver. As such, all of its operating parameters are controlled by software. With this radio I can open up the transmit bandwidth to accept the rich fidelity of the RE27. The transmitter will still be able to be a "good neighbor" on the bands by not exceeding the set bandwidth. I will still have the same problem at the other end. The other folks still have inconsistent receive quality. At least I know at my end it is the best it can be. The real joy comes when you and the other person both have the ability to run high fidelity audio. This type of audio is not suited for weak signal work or seeking distant contacts. It is meant for enjoyable conversation.
Is the RE-27 possibly the finest microphone ever made? Possibly. Do you need it? Probably not. If you get it, will your world be changed? Probably not. Many users compared this mic with the Heil PR-40, the Audio Technica AT-2020, and the Behringer XM8500 Ultravoice, Various tests results did not reveal a clear winner. That's probably because of human perception. The AT-2020 and the PR-40 suffer from proximity effect. Radio listeners might not notice this unless the person transmitting is constantly changing his distance from the mic. Many people are fond of the Behringer XM8500. The Behringer XM8500 Ultravoice goes for about $20. Music vocalists say the XM8500 sounds as good as the industry standard Sure SM58 which goes for about $100. If you want a great mic that won't break the bank, you can't go wrong with the Behringer XM8500. Don't get the Electro-Voice RE27 unless you have a transmitter that is capable of showcasing its fidelity. If you get the Electro-Voice RE27,don't be disappointed if some people don't even notice it. You can't go wrong with the RE27. You may question whether the RE27 is worth the cost for Ham Radio use.