By David - K3DAV
Have you searched and searched for a good speaker for your ham radio? That perfect speaker that would let you hear voices through the noise and static without hiss? A speaker that isn't fatiguing to your head after listening for a while to weak signals? If you are like me, then you answered yes.
There are several speakers on the market designed for communications. A lot of us long time operators use a good set of headphones to hear those weak signals, or to just enjoy the clean crisp audio of the strong signals. Headphones are probably the best for this purpose, but they can get annoying after wearing them for a while. I was using a small but good quality bookshelf speaker designed for lower powered stereo systems. It sounds pretty good, but it's still not what I want.
So I decided to start looking at what the ham dealers had to offer. The first speaker that caught my eye was the "SOUNDS SWEET" speaker. It had nice specs and a lot of good reviews. So I went to the Sounds Sweet website, got out the old trusty plastic credit card, and ordered me up one of those puppies.
I got it delivered in 3 days. Took it out of the box and sat it on the counter next to the radio. It was heavy duty construction and very professional looking. I hooked up the wire and plugged it into the back of the radio. At first I wasn't sure what I was hearing, but I gave it the real test on 20 meters where there is usually a few hams in DX wrapped up in a pile-up. I found this ham in Italy trying to talk to several hams in the USA. I listened for a while to several signal strengths with different audio tones. They all sounded about the same. Very bassy and even a little muddy. There were no higher tones of any kind. It was like listening to my stereo with the treble control turned all the way down. I tried changing the tone controls for the receive on the radio, but the treble control seemed to have no effect at all. The speaker was blocking it all out. It appears that the speaker in the pretty box was just a woofer with barely any upper voice frequency range. I was not happy. I reconnected my little bookshelf speaker and it sounded much better. And for the record, I have excellent hearing.
I contacted the owner of Sounds Sweet, and told him of my disappointment. He said it could be a bad speaker and to send it back. He said he would check it himself and if it was faulty, he would send me a new one. So I sent it back. He contacted me saying that there was nothing wrong with the speaker. But he would be glad to send me a replacement. I figured if there was nothing wrong with the one I sent back, then a new one would sound the same. So I thanked him and got a refund. I really thought all the hype made it a good choice, but I was wrong.
So the search went on for that nice sounding speaker. I tried a few others like the Clear Speech speaker, and even the speaker from Icom that matches my Icom 746PRO. They were OK but they lacked a certain amount of natural tone quality found in voices. The sound was always too tinny, or too bassy, or muddy, or flat with poor voice ranges....blah blah blah.. I got tired of searching and kinda gave up trying for a while
Then All Of The Sudden It Hit Me.
I am an audio/video enthusiast. I have a rather nice home theater surround system with High Definition TV and digital theater surround sound. I was watching the movie Top Gun in HD. And when they are talking, the dialogue is routed to the center channel speaker under the TV for the effect of their voices coming from the screen where the people are. I sat up to get a little closer to the speaker and just listened. The voices sounded so natural and clear. I put the movie on pause, and looked at the speaker. Then I looked over at the Icom 746PRO. Then back at the speaker, then back at the radio.......this went on until I realized how stupid it looked, then I stopped to think about it.
I got a long piece of wire and ran it from the center channel speaker over to the radio. I quickly hand wrapped the wires to a jack just for the test, and plugged it into the back of the radio. I turned the radio on to trusty old 20 meters and found a DX station in a typical pile-up. I went back over and sat in front of the speaker and just listened for about 20 minutes. I could hear and understand every word they were all saying. There was such a very tiny amount of hiss, but it was far too low to bother me. The voices rang out clean and clear. Even the weaker stations sounded clear enough to understand easily, even through the noise. I had heard enough to move the speaker next to the radio and try it out for a few days. So I did just that. I temporarily used the bookshelf speaker to replace the center channel speaker on the home theater system until I decided what I was going to do.
Now just think about the logic in this. A center channel speaker is designed for dialogue, (Voices). So the speakers and the built-in cross-over network is also geared for the voice range. Of course I realize that a radio does not cover the audio frequency range that a stereo system can. But neither does the center channel speaker, and that is the logic of it.
The speaker I am describing is the Optimus PRO CS-5 center channel speaker. It is the speaker in the photo at the top of this page. Back in 1999 it cost me $120. It has 2 long throw 5 1/2 inch mid-woofers. After checking the cross-over network, these 2 speakers are cut off below 70Hz but only up to 3,500Hz. This is the average range that any good ham radio can produce. The tweeter is a 2 1/2 inch monopole ribbon tweeter. It's cross-over allows only the range between 2,600Hz and 25,000Hz to pass to the tweeter, and frequencies above 15,000Hz have a subtle roll-off in dB. The tweeter also has a resister in line to cut back the volume to the tweeter. This makes the higher frequency range much more subtle, not as pronounced. It is a nice balance for voices. The soft level of the tweeter adds just the right amount of highs to compliment the mid-woofers which do 80% of the work. But the hiss and high frequency static sounds are not heard.
The center channel speaker sounds rich but very clean. And even though this speaker is rated at 100 watts of audio, it still delivers far far more than enough volume without any distortion. I still run the volume on my radio at the same levels I always used. Those hams with that nice bass on SSB sound fantastic. Simplex FM stations sound like a nice Public Address system. And I have to say, I have never heard AM Short Wave stations sound that good before. The tones of CW stand out loud and clear way above the noise level. The bass is clean but not muddy or mumbled. If the noise is very low, and you listen hard, you can hear the high frequency hiss. But the hiss is so far in the background, you tend not to notice it. Even the noise is not fatiguing on my ears.
Needless to say, the PRO CS-5 has now become the only speaker for my ham radio. I have had a few friends visiting, and complimenting me on how nice and rich the speaker sounds. Just hearing mine convinced them to buy a center channel speaker for their own radios, and they couldn't be happier.
Don't Go Cheap. This Is Important.
If you decide to try this type of speaker for yourself, do not get a cheap speaker with a $30 price tag. Spend the extra cash and get a high quality center channel speaker with 2 speakers that are 5 inches or larger. They can range these days from $150 and up to $1,000. But the $150 to $300 version will do the job quite nicely. Hell the "Sounds Sweet" speaker costs $160, and the center channel speaker blows "Sounds Sweet" away. Also, only get one with speakers of 5 inches or larger. Don't waste your money on smaller speakers. They will lack the lower tones that make your radio sound rich and natural. The cheaper speakers also have poor cross-over networks that deliver too much high tones with hiss. Like I said, spend the extra cash on a quality speaker with at least 5 inch speakers. I think you will be surprised at what you hear. I know my search is over.
PS. I got a new Polk center channel speaker for the Home theater system. Two sound problems solved.
If you have any questions or comments about this article, please feel free to contact me at firstname.lastname@example.org