SGC ADSP2 SPEAKER

 The first thing I noticed is how small this speaker is.  It is about the same height as the IC-706 and actually is a beautiful match for the IC-706.  It is also an excellent size for mobile use. 

• The case has a rugged feel as you handle it.  The case is made of black plastic with a metal speaker grill.  It has a nice black finish.  It has a metal U shaped mounting bracket attached to each side of the case with two short knurled, Allen head screws.  There are two threaded brass inserts in the case.  These screw heads are just large enough to allow adequate tightening using your fingers.  CAUTION! Do not replace these screws with longer screws.  If you do the screws will run into a PCB and damage it.
• The shielded speaker cable is six feet long and has a molded 3.5mm miniature plug on the end.  The red and black Teflon power cable is three foot long and uses stranded tinned wire.  These cables are not removable from the unit.
• A Lexan placard is glued onto the rear case and covers the four mounting screw holes.  I was able to lift both ends of this placard to access the mounting screws for disassembly. 
• The following information is printed on this- placard: 
  1. “For noise reduction in AM, SSB, FM, and CW operation” 
  2. Red LED = Power On. 
  3. No Green LED = Bypass. 
  4. Single Green LED = 13dB.  Two Green LEDs = 26dB. 
  5. Red Power Wire = +12 VDC.  Black Power Wire = Ground. 
  6. Input VOLTAGE = 10 – 15 VDC. 
  7. Current Consumption (no Input) = 90mA.  Max Signal = 300ma. 
  8. Max Output = 4 Watts. 
  9. Max Drive = 5 V RMS. 
  10. Made in USA.
• Inside there are two SMT printed circuit boards and things are very densely packaged. 
• Three LED’s are mounted ½ inch behind the speaker grill.  In the upper left corner is the Red Power LED.  In the upper right corner is the Green 13dB mode LED.  Just below this LED is the 26dB mode LED.  All the LED’s disappear from view when the power is turned off. 
• A grey push button on the top is used to toggle between; BYPASS (power on default) 13dB (single green LED) and 26dB (double green LED). 
• There is no Power On/Off switch so you need to provide power from a switched + 12VDC.  This is often available on the rig’s rear accessory connector.  Most new radios provide this. 
• The internal speaker is a good quality “Acustic Suspension” speaker.  It can handle 4 watts of power. 

 

OPERATION

This is definitely a communications speaker.  It is not designed to be a Full Fidelity Speaker.  The low frequency range is missing but that is to be expected for its size.  The frequency response provides excellent communications quality audio.  This speaker is designed to provide maximum speech intelligibility. 

The speaker is best suited for Mobile installations or other noisy environments.  It may not be the best choice for Evening Hi Fidelity Rag Chewing in front of your base station.   

The ADSP2 has an Automatic Notch Filter (SNS) running all the time in addition to Noise Reduction.  I found it very effective in removing all carriers that occur inside the receiver pass band.  In CW mode the Auto Notch Algorithm will not try to attack the CW tones.  You can use all the features in the CW mode.

The noise reduction algorithm in the ADSP2 speaker does remove noticeably more noise than the IF DSP in my IC-756ProII.  Pierre Goral is correct when he claims that the ADSP2 will perform better noise reduction than the best IF DSP in today’s radios.  Our tests confirmed that it does just that.

This speaker is excellent for long periods of HF monitoring.  On the mission field we often find ourselves listening to HF for 7 to 8 hours each day.  We operate this way with our mission aircraft when they are flying over the jungle to small villages.  We also monitor each of the village HF stations in case they need to call during the day.  The noise fatigue levels become very high during this type of operation.  With the use of the ADSP2 the operating noise fatigue is greatly reduced. 

I have noticed that I can get up and walk away from the radio into another room and still clearly understand the audio from this speaker.  The missionary wife can do her chores around the house and still hear the radio calls. 

The ADSP2 makes HF Radio operation enjoyable again.  We are so impressed with the advantages of the ADSP2 that we are considering installing them in all our HF radios around the world.  The ADSP2 provides a measured improvement in our HF radio environments. 

I made one modification:  I installed a 3.5mm switched jack on the back panel (lower right side).  This jack is connected to the internal speaker.  This allows the internal speaker to be disconnected when you insert a plug into this jack.  Now, I can try out all those favorite external speakers, that I have lying around, to see how they sound with the ADSP2.  This gives me the best of both worlds.  For example, I can use the SGC speaker Mobile, and still use it with my favorite speaker on the Base Station. 

The SGC ADSP2 is truly an excellent product at a good price.  Every Ham should have one of these around.

We had the opportunity to compare the SGC ADSP2, side by side with, the Clear Speech, and the GAP Hear It speaker.  Some of our findings are listed below:

• Ray Rising K4LWJ reports that there is no noticeable “Alternator Whine” introduced into this ADSP2.  He did have “Alternator Whine” using the GAP Hear It speaker.  He also says: “It seems to me that there is more background audio processing compared with the “Clear Speech” DSP speaker”.  The “Clear Speech” has only 12db of noise reduction.
• Ron WB4OOA reports that he likes the audio quality of the ADSP2 over the GAP Hear It.  He also likes the noise reduction better.  The automatic Notch feature is excellent. 
• The only problem we found was:

When the DC voltage is applied intermittently the unit may not operate correctly. 

Just disconnect the DC and hook it up cleanly (preferably through a switch) and it will work normally. 

Ron Durie
JAARS INC