IC 7000

Had a bit more time to play around with the 7k and do a bit of research on the mic the oft reported audio problems in the mid and narrow Transmit Band Width (TBW) settings. . Needless to say as long as you leave the TBW in wide you won’t experience any problems…just nice clear audio. Bob Heil of Heil Sound fame has got into the act and has a fine article on his web site outlining the problem and suggested fix. It concerns a little mic at the bottom of a tube and an offset hole for the audio to get through. More like a placement thing but he did say there seemed to be a problem in the audio amplifier on certain frequencies which didn’t help.
I had already set the TBW as follows: wide 100-2900, mid 200-2900, narrow 300-2800 which was OK with the standard mic and fine with the Heil HC-5 and HC-4. I was getting better reports with the HC-4 but had to crank up the compression and mic gain more than with the HC-5 and std hand mics.
The RIT was given me heck as I didn’t seem to be able to find it when needed. Now I have it on all the time but I have lost the ability to change between the memory banks without some knob pushing and praying but that is less of a problem as each bank holds 100 memories. The outside knob is now the clarifier unless I am fiddling around with the RX bandwidths which I am slowing starting not to do…novelty wearing off and seldom helps on SSB …easier to use the 3 preset bandwidth filters of 3.0, 2.4 and 1.8. audio through the headphones a lot better than bult in speaker for sure.
Thought I would sell it but now I am starting to like it…..
 
Anyway..here is what Bob has to say…..Loks like the photos did not come accross. www.heilsound.com
 

HEIL MICROPHONES WITH THE iC 7000


All of our products built for the 706 will work well with the sensational new iCOM IC 7000. The Traveler 706, the iCM with the HSTA 706 adapter and the favorite is the HM-iC HANDI MIC with the Ch -1 iM cable. For the ultimate headset operation any of our IC headsets (BM-10 IC, PRO SET IC, PRO SET PLUS IC, PSQP IC) with the AD-1 icm modular adapter and HS 2 or FS 2.

Set the Transmit bandwidth in the WIDE position 200 Hz and 2900Hz. For extreme articulation, contest or DX pileups ups use the MID or narrow bandwidth filters.

The IC 7000 has extreme audio capabilities. Here in the Heil lab we have been VERY successful in using the 8 band W2IHY EQ into pins 2 and 11 of the rear accessory socket. Using the PR 40 with this set is absolutely stunning. Transmit Bandwidth set at 100 Hz and 2900 Hz.


Jan. 12. 2006

HC 5 on the IC 7000

Because of the lack of mid range and high frequency articulation in the IC 7000, you will discover that the HC 5 will give you the best results. I am using the HM-5 Handi Mic with the CH-1 IM modular coil cable for the 7000. You could use the HM-10-5, the GOLDLINE GM-5 or any of the headsets using the HC 5.

You will have to set it up correctly.

COMPRESSION On all the time. Set to 4
MIC GAIN sets about 50% – or where the ALC meter is happy
WIDE transmit filter set at 200Hz and 2900 Hz.

This is actually giving the best results as the HC 5 ads such wonderful articulation.

The key to getting decent audio is to set the 7000 low end at 200 Hz. and 2900Hz. on the top. There seems to be some weird anomaly with the mic pre amp section that when hit with lots of low frequency energy from the microphone, the transmitter gets "hollow’ or boxing sounding. Moving the transmit bandwidth filter to 200 Hz. (not 100 ) seems to solve a bit of that. The HC 5 helps more as it doesn’t start up until 300Hz so it is a perfect match for the IC 7000.

When the compressor is used at the low level of 3 or 4 it acts as an additional microphone pre amp. Just what is needed when using low level dynamic elements such as the HC 5. It truly has been the best
combination so far.

Help is on the way. Stay ‘tuned’ to this billboard about the IC 7000. We will add additional info during our IC 7000 project.


Jan. 13, 2006

Bob:

Just a short add-on — one of my customers bought the Traveler for his
7000 and he is getting tremendous signal reports. Jay, WS1CO at HRO in Denver.


Jan 17, 2006

This has been a struggle….and not finished yet, HOWEVER I think that I have a fairly quick and easy modification to bring the iC 7000 transmit audio alive.

We all know how incredible the receiver is….but the hollow sounding transmit audio continues to plague all of the new owners. There are several problems. The first being that the iC element in the stock microphone is only 1/8" in diameter and 1/16" thick. This element fits TIGHT into a rubber ‘tube’ which is part of the 25 button mask. Would you mount a toilet paper tube in front of your GOLDLINE? That is EXACTLY what they did – but that is not all. The toothpick size opening you speak into is 1/4" to the right of this tiny element so your speech goes down inside this tube, hits the p.c. card and reflect back up to the top fact of the microphone, reflecting again back down to ‘find’ the element. All of this phase distortion is what causes a lot of this ‘hollow’ and boxy sound we hear from the 25 button microphone.

In addition, there is some anomaly in the speech amplifier frequency response giving a rise around 300 to 500 Hz…right where things get ‘hollow’ sounding. Add these two together and guess what?

You got it….Hollow and Boxy sounding !

There is no articulation using this microphone into this fabulous transmitter.


In looking at this 25 button microphone, I discovered that our HC 5 or the HC 4 (both which has become THE choice for the DxPedition and contest ops) fits – EXACTLY in the area on the BACK of the stock mic that they intended as a ‘hanger’….well thank you, iCOM for doing that AND obviously using our HC element as a mold for that spot!

I had to shave just a bit of the ‘bar’ of plastic for the HC 5 to slide into but the HC 4 fit perfectly. Drill one hole and install a short small diameter shielded wire down to the two points where the original electret was installed. Don’t forget the 1 mf non polar decoupling cap. There is some kind of plastic ‘fence’ molded on the inside of the back plate…they even left a small cut out to run our wire to the original element location ! The two solder points of the original element (outlined in a white square) are located right under the i.C. This is where you connect the shieled cable and de coupling cap.

I attached some audio files for you to hear. Interesting….because of the +6dB of 3K rise of the HC 5, I back the transmit bandwidth down to 2700 and 100on the low end becuase it rolls off at 300, thus NOT allowing the internal preamp to be hit with a lot of low end as the stock iC did causing that horrible hollow sound. Use the COMPRESSION – always to get the needed gain and that sets at 4. NOW, the iC 7000 in my statioin lab finally has some articulation.

Gentlemen – THIS is the answer !…..well for now.

My OTHER project and is REALLY the fix is in our tooling shop as we speak…couple of weeks, I should know about this. We have built our 1982 two band EQ 200 (the gadget that started ALL of this higher quality audio ) into one of our wonderful little Handi mics. Two 1/4" holes on it’s back allow you to set the treble and base. THIS is really going to be the answer if all works out. The prototype certainly works well. MUCH more later.


Feb. 06, 2006


Step #1 – Mic Apart


Step #2 – iC7000 Entrance


Step #3 – Top Of Mask


Step #4 – Mask Shown


Step #5 – Mask with iC element

The huge problem with the stock iC 7000 ‘hand mic’ is three fold. First, their electret is VERY small about 1.8" dia and 1/16" thick. It is soldered to the bottom side of the p.c. card. A rubberized ‘mask’ that is molded to form the buttons and control you push has a ‘tube’ that seals this tiny element on one end and seals against the top plate where you speak into, thus forming a 1/4" tube from the entrance hole to the element. Think about talking into a tissue paper tube in front of your microphone!

But this is not the worst issue. The hole you speak into is NOT centered into that tube. The pencil lead sized opening you speak into is 1/4" to the right of that entrance thus your speech enters the hole hits the p.c. card, reflects back up and eventual finds the entrance hole and back down to the element…all of this roaming around causes severe phase distortion and cancellation of mid range frequencies. Mids and highs goes in a straight line. Period. When trying to reflect these frequencies, all kinds of phase distortion occurs…..thus the ‘hollow’ sound the iC 700 exhibits.

One of the issues is also it’s a hollow clam shell ‘hand mic’ with the element INSIDE. Our Handi Mic technology has solved this 50 year problem! http://www.heilsound.com/amateur/handi_mic.htm

All of this can be proven in the attached photos. One of the easiest fixes is to install our HC 5 on the OUTSIDE after removing the teenie electret and soldering a shield lead from those points to our HC 5 AFTER decoupling it with at least a 1 mfd. capacitor. (there is D.C. on those mic inputs for their electret)

BOB HEIL, K9EID
http://www.heilsound.com

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