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Audio Audio Audio

Discussion in 'Microphones, Speakers & Audio Processing' started by K1DNR, Mar 10, 2011.

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  1. K1DNR

    K1DNR Ham Member QRZ Page

    Interesting. Its the lack of bottom vs the peak that I'm missing. I think the HC-4 is just a bad choice for my particular voice which is not particularly bottom heavy. The lack of that strong 3KHz peak is probably what the guy complained about with the Samson. All cords are shielded, proper audio cords - although the balanced output of the "stage" mics gets "converted" to unbalanced by soldering the shield and pin 1 together. My XLR 3 to XLR 4 adapter is only a few inches long. I'll see if a few more feet of distance from the power transformer helps any.

    Thanks for the advice
     
  2. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    Personally, I don't know why some folks are dead set against using a stock, hand-held microphone. Most (I didn't say all) utilize electret condenser elements, which have a virtually flat response from 20 Hz to well beyond 20 kHz. If you use them correctly, I believe they sound as good as any aftermarket one you can buy, no matter the price.
     
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Charley,

    First thing I'd do is call Bob Heil on the telephone and ask him some questions about your mike and rig. Bob's tried all sorts of combinations and knows a lot of tricks that never get published anywhere, not even on his website (which is not updated very often). He's a very active operator.

    Also when dealing with almost any kind of mike remember "close talking" with the mike gain set as low as it can be for full modulation always sounds better than any other combination. It will minimize background noise and provide more rich, full tonal quality with most mikes. There are some exceptions (some ribbon mikes, shotgun mikes, etc. designed for very low sound pressure), but every mike I have (a lot of them) sound better when used less than 1" from the lips, with the gain set as low as it can be while still providing modulation.

    To adjust my settings I use a separate receiver with headphones. The RX I've been using for that for a long time is an old Collins 75A-4; it has 3.5 and 2.1 kHz filters and I try to make my audio sound good with either one. Of course the 3.5 passes a lot more spectrum and sounds "fuller" on anybody's signal, but with proper adjustment I can get my TXs to sound good even using the 2.1 kHz RX filter. Takes some balancing, although I don't use any outboard EQs or anything -- just what's in the rig.
     
  4. N4BBQ

    N4BBQ Ham Member QRZ Page

    I have tinkered around some with different mics and found that the electret mics do work very good. The setup I have now is a Logitech Headset and the mic is biased with a 15k ohm resistor to +8V from the radio, and the audio bypass cap is a 0.022uF. People that know me tell me this sounds like I do in person and I think that is what you're looking for. Good luck in your search.
     
  5. NY3V

    NY3V Ham Member QRZ Page

    I've been meaning to find and try some free downloaded audio editing programs to play with.

    Has anyone found one that is easy to use and works well?

    [​IMG]
     
    Last edited: Mar 10, 2011
  6. K1DNR

    K1DNR Ham Member QRZ Page

    Try Audacity. It is free and very easy to use. Works well. Has some decent built-in effects. Can interface with add-on effects as well. Windows or Linux. Not sure about Mac (but there are lots of other Mac options).
     

    Attached Files:

    Last edited: Mar 10, 2011
  7. K1DNR

    K1DNR Ham Member QRZ Page

    Steve - I have exchanged a few emails with Bob but I haven't gone this deeply into it with him. He's got an audio sample of the HC-4 cartridge on his site that sounds almost exactly like mine. So it was a poor choice on my part. I may exchange it for the one with the wider range. I really don't want to get into any outboard EQ, etc... The plots on Heil's site, and the ones Owen linked are pretty much what I hear. Rapid roll off of the low end, and a huge 2K-3K peak. With the gain and processor adjusted properly, it sounds like the classic "Space Shuttle". Very constricted, and nasally.

    BBQ - yes, I got a Logitech headset working as well. But I have a huge problem with RF getting into that one. There are many possible reasons why, and I just haven't gotten around to experimenting with different shielding, etc. The modular mic connector on the Yaesu makes it a bit tricky to get the shielding right as well. My next effort was to sheild the case containing the caps and resistors, and get some shielded Cat5 for the short lead to the rig. It comes with a foil shield and a ground wire that can be grounded to the case directly. Just haven't had a chance to try it yet.

    BG - I have used really cheap mics on things. I've heard guys on the air using very cheap mics, computer headsets, etc... They also sounded pretty good. A couple things on the stock hand mic: It is a hand mic, which gets tiring after awhile - such as a contest. Then there is the hand noise of keying the mic, holding the mic, etc... You are absolutely right, however it depends on the audio bandwidth on both sides, etc...
     
  8. VK1OD

    VK1OD Ham Member QRZ Page

    Read again, most magnetic capsules are far more sensitive to stray magnetic fields that an electret. Magnetic capsules are more likely to suffer from induction of hum from transformer leakage, and the effect is often diagnosed as 'RF in the audio', but since the 50/60Hz induction is way down in the receiver's response, it is not heard (unless you tune off and hear the beat note from it), but it intermodulates with the voice (no linear PA is perfect) and gives it a certain roughness.

    If you are using a magnetic mic, it is worth moving it close to the power supply (where it almost certainly will pick hum up), rotate it to verify that it is magnetic pickup, then move it back to the operating position to determine if the hum reduction is adequate in the normal operating position and orientation.

    As an example, the pickup in a TS2000 stock hand mic was objectionable at up to 1m from the power transformer in an AL811H on the desk top.

    Shielded cables are not the problem in this case.

    In any event, shielding works differently at audio frequencies, mainly because skin effect is not well developed, current that flows on one side of a simple conductive shield reaches the other side of the shield.

    Owen
     
  9. NY3V

    NY3V Ham Member QRZ Page

    Thanks Charley.

    Have you tried using it to enhance your transmit audio?
     
  10. K1DNR

    K1DNR Ham Member QRZ Page

    Owen - thanks for the additional explanation. I was with you on the magnetic fields, I meant I'm pretty sure the cables are properly shielded and that isn't a cause. My quarters are a bit cramped - so it would make absolutely perfect sense. I'm well inside a 1m radius.
     
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