OK, I just ran my test again, but this time turned the monitor up all the
way, and i did indeed hear monitor audio in the speakers. I stand
corrected, and sorry for muddying the waters.

No, I wasn't confusing Phones and Line Out.

At any rate, at a 'normal' (for me) monitor level, it's not objectionable
(or even really noticable) in my external speaker. The only way I could
induce audio feedback was to hold the mic right in front of the external
speaker with MON set at or near maximum.

I can't honestly think of any reason one would want TX monitor audio in a
loudspeaker, but I guess that's the way it works, so somebody must think
it's a good idea.  I can't say I've ever noticed it until doing this test.
Whether it results in audio feedback depends on your monitor level, your
mic, your speakers, and the placement of mic and speakers relative to each
other.



On Sat, Apr 8, 2017 at 3:24 PM, Joe Subich, W4TV <li...@subich.com> wrote:

>
> On 4/8/2017 2:19 PM, Dave Fugleberg wrote:
>
>> 2) If you use the REAR panel phones jack, the monitor audio comes
>> through the phones as expected. If SPKR+PHONES is set to yes, the RX
>> audio comes through the speakers, but the transmit Monitor audio does
>> not.
>>
>
> That is *NOT* my experience.  With 5.57, the front and rear panel
> headphone jacks behave identically here.  You may be confusing the
> Phones and Line Out jacks.
>
> 73,
>
>    ... Joe, W4TV
>
>
>
> On 4/8/2017 2:19 PM, Dave Fugleberg wrote:
>
>> I think some of the misunderstandings on this thread are because the front
>> and rear panel Phones jacks behave differently. Here's the deal:
>> 1) the original poster is using the front panel PHONES jack, and has
>> SPKR+Phones set to NO. This makes the radio behave like most rigs we're
>> used to - i.e., plugging in the phones mutes the speaker. In this case, if
>> Monitor is on, it comes through phones OR speaker, whichever you're using
>> at the time.  There is no provision to enable/disable Monitor based on
>> whether the front panel phones are plugged in, which is what he wants.
>>
>> 2) If you use the REAR panel phones jack, the monitor audio comes through
>> the phones as expected. If SPKR+PHONES is set to yes, the RX audio comes
>> through the speakers, but the transmit Monitor audio does not.
>>
>>
>> At least, that's the behavior with my K3, MCU version 5.57.  I just tested
>> the two scenarios above.  For the record, my normal configuration is to
>> use
>> the rear panel phones and mic jacks, with SPKR+PHONES on.  I do have PF1
>> set to toggle that off, but rarely do, since I'm usually alone in the
>> shack.  I have yet to hear any kind of audio feedback when transmitting.
>> I
>> have no idea if the behavior is any different using the front MIC jack, as
>> I never do.
>>
>> I'd be interested to hear if anyone has a different experience.
>>
>> Incidentally, while testing option 1 above, I unplugged the phones from
>> the
>> front and cranked the MONITOR until it was unpleasantly loud from the
>> speakers, but got no feedback howl, but that may just be a function of
>> placement.
>>
>> On Sat, Apr 8, 2017 at 1:02 PM, Richard Lamont <rich...@lamont.me.uk>
>> wrote:
>>
>> On 08/04/17 18:11, Joe Subich, W4TV wrote:
>>>
>>>>
>>>> On 4/8/2017 2:24 AM, Richard Lamont wrote:
>>>>>
>>>>>> The firmware, however, does not appear to support what seems a simple
>>>>>> and common-sense requirement.
>>>>>>
>>>>>
>>>> It is *not* the firmware - it is the *hardware* that does not support
>>>> what you call a "simple and common-sense requirement" and what others
>>>> call stupidity.  Perhaps you should study the schematic - at least of
>>>> the K3 which is published.   Notice on the sheets K3 DSP: CODECS and K3
>>>> DSP:DAC AUDIO the headphone/speaker amplifiers are fed *IN PARALLEL*.
>>>> LHPOUT/RHPOUT of U7 (the DC) goes through the audio lowpass filter to
>>>> U1 (speaker amplifier) and U2 (headphone amplifier) *IN PARALLEL*.
>>>> *THERE IS NO POSSIBLE WAY* to send monitor audio *to only* the
>>>> *headphone amplifier* (or for that matter *only* to the speaker).
>>>>
>>>
>>> I studied the K3 schematics a few days ago. I've just studied them
>>> again. Thanks for the reminder.
>>>
>>> On receive, the rig is capable of muting the speakers when the
>>> headphones are plugged in. This is quite normal. This happens despite
>>> the two audio amplifiers having parallel inputs.
>>>
>>> There are switch contacts on the front panel headphone jack that enable
>>> the rig to 'know', firmware permitting, whether there's a jack plug in
>>> the socket. There is also a line labelled MUTE1 connected to the pin 2
>>> of the speaker amplifier U1.
>>>
>>> So the hardware exists to enable the firmware (a) to know whether
>>> headphones are plugged in, and (b) to mute the speaker amplifier. This
>>> hardware is, AFAICS, used on receive. All I'm asking for as an option to
>>> do the same thing on transmit, if a particular set of circumstances is
>>> true:
>>>
>>> Is the rig on a voice mode?
>>> Is the audio input set to mic (not line in)?
>>> Is the rig transmitting?
>>> Is there nothing plugged into the front panel headphone socket?
>>>
>>> If these four conditions are all true, then mute the speaker amplifier.
>>>
>>>
>>> 73,
>>> Richard G4DYA
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