Topics

Direct Audio into the Mac

Craig T. Bailey
 

Well, I'm pleased to say I've got the Morserino piped into my Mac.

In addition, I built a mixing circuit to blend a wired mic input with the line out audio from the Morserino.

This mixer goes into a USB dongle audio card.

Why? you might ask?

When participating in CW Ops Academy, or any other video conferencing system, where you are working with other Morse trainees, its common place to just let the PC's built in mic pick up the code oscilator's side tone over the air.

I'm finding skype was terrible at clipping the keyer, and Zoom wasn't much better. By having it piped direct, the folks on the other end get clean code. Also, by piping it direct, I'm using my headset plugged into the PC (Mac in this case) as the monitor of the side tone.

I suppose this is also precisely what the Mumble app needs as well.

Just one more reason why Morserino is a GREAT educational tool!

Chuck Broadwell, W5UXH
 

On Sun, Aug 4, 2019 at 12:15 PM, Craig T. Bailey wrote:
I suppose this is also precisely what the Mumble app needs as well.
Correct.  Mumble is full duplex so many newcomers to it have problems with the open mic and a speaker.  Turning off the speaker and using headphones makes it usable, but it is far nicer to have a sound card input.  I do not participate in CW training sessions, but still occasionally need to use a mic with newcomers.  On the Mac, a very nice tool is available (unfortunately it costs the same as the M32).  It is LOOPBACK2 from Rogue Amoeba.  It allows you to create virtual audio devices for mixing and pipelining audio between various apps.  I have one virtual device that combines my external sidetone input with the webcam mic when I need to add "voice".  It is also very handy for playing recordings back to someone over Mumble.  I just select the my virtual device that mixes the Audacity output with my input sidetone to select as the input device to Mumble.

Ben Cook
 

That’s pretty cool. I’m starting a CWA session here in a couple weeks and this would be very useful. I do have a Mac program called Audio Hijack from Rogue Ameba which *might* let me pipe the audio in from the built in mic port and a headset into the Zoom conference. I’ll have to give that a try tonight. Else any other details how you accomplished this with your usb mixer?

-- 
  Ben Cook
  ben@...



On Mon, Aug 5, 2019, at 05:49, Chuck Broadwell, W5UXH wrote:
On Sun, Aug 4, 2019 at 12:15 PM, Craig T. Bailey wrote:

I suppose this is also precisely what the Mumble app needs as well.
Correct.  Mumble is full duplex so many newcomers to it have problems with the open mic and a speaker.  Turning off the speaker and using headphones makes it usable, but it is far nicer to have a sound card input.  I do not participate in CW training sessions, but still occasionally need to use a mic with newcomers.  On the Mac, a very nice tool is available (unfortunately it costs the same as the M32).  It is LOOPBACK2 from Rogue Amoeba.  It allows you to create virtual audio devices for mixing and pipelining audio between various apps.  I have one virtual device that combines my external sidetone input with the webcam mic when I need to add "voice".  It is also very handy for playing recordings back to someone over Mumble.  I just select the my virtual device that mixes the Audacity output with my input sidetone to select as the input device to Mumble.

Chuck Broadwell, W5UXH
 

On 8/12/19 11:02 AM, Ben Cook wrote:
I do have a Mac program called Audio Hijack from Rogue Ameba which *might* let me pipe the audio
Ben, I don't think Hijack lets you pipe audio, I think it only lets you capture and record it. The Rogue Amoeba Loopback 2 program works very well for creating virtual audio devices and then piping them. The free trial is a "30 times running" limit, not a 30 day limit, so you could still make use of it without having to purchase the software. At least the last I checked that was the trial policy. Good luck.

Chuck
W5UXH

Craig T. Bailey
 

Hi Ben,

CW Ops Academy is precisely why i've been working on getting CW piped directly into my computer.

I've done several classes where students will "send" from their oscillator, and Zoom, or Skype, would simply pick up the code through the internal microphone on the computer.
Let me tell you - its an awful experience!
Half the time the zoom client will clip the audio when a dit is sent first, the other half the time some other person has their microphone open, so you hear yoru own code echoed back over zoom because people don't know how to mute their computer mics.

So, I'm trying to come up with a simple way to pipe this all in.

Chuck's point is a good one - an internal sound mixer app with virtual devices will work. Although I fear the technical level of most "students" in these morse code classes will prevent that from happening.

On the Mac, i've had some good success with an external USB sound card (dongle) but, I needed a custom built audio summing circuit, and a wired mic to pipe the morserino and my mic together. Then in the mac... the OS has a built in app called "midi" that will let you build "aggregate" devices. The midi app doesn't sum/mix the audio channels, though.

The ultimate tool would look like this:


box that will let you plug in:
1. a 4-conductor TRRS line from the morserino (for audio into morserino and audio out of morserino)
2. a 4-conductor TRRS wired headset (for mic into the zoom app, audio out of the zoom app, AND a monitor of the morserino output)
3. a 4-conductor TRRS output back to the PC/Mac to carry audio into and out of zoom.

On a 2012+ mac book, the headphone port is actually a TRRS for phones & mic.
I have a dell precision that also has a TRRS port for onboard sound and mic.

Can someone help me with the circuit design? The box should have gain control to reduce or increase the volume of each input and probably a master output?

I have built the summing circuit that I found at Rane.com https://www.rane.com/note109.html
And it works pretty good, although there is potential for some ground looping. (I've used this in my car to pipe together my 2-meter radio and a MP3 player into the car's aux jack)
But I think the added complexity of the TRRS (4-conductor) ports AND the concept of audio input & output qill require a better design.

I'd be interested in working with someone to develop this circuit and a Bill of Materials, because I think the Morse-Learning community has fully adopted video conferencing, but the audio NEEDS to be piped into the system. I can handle soldering, and reading schematics, but I've never designed a circuit from scratch.

Thanks very much



--
_____
Craig Bailey
N1SFT
NH, USA

Thomas Ruhmann
 

Hi folks,

I soldered a cable from the morserino TRRS input/output to the input of a external USB soundcard and get the sinus tone as input. Then I tried to reroute the tone to another soundcard output to hear it.

I´m actually in the first cw academy course and think also about piping in the cw tone directly to Zoom.

My problem is, that the latency of the output tone is to long - so there ist no hand-ear synchronicity possiible.

I´m using Windows 10 with VAC and Audio Repeater for routing. Any ideas to decrease the latency?

Best regards Thomas DG6UAX

Craig T. Bailey
 

Yep.  I’m in the same boat with the latency.

 

I’m designing an external circuit based around the OpAmp which will combine the audio out from Morserino directly into the headphone output to work as a direct monitor.  Of course that morserino line out is also going to be SUMMED with my headset microphone, and that SUM signal is going to be fed into the lineIN on the mac.

 

I’ve given up on the software audio mixing.  The latency is just too much.

 

But, something must be designed soon, and produced cheaply, because so many of us are doing Morse into Zoom/Skype, and the audio coupling is just horrible.

 

Not to mention those PC Mics that do not even trigger until 30 milliseconds after a DIT is played… learning Morse over zoom is actually harder because of all these audio problems.

 

Then we have some guys that must be using dial up connections… the list goes on an on.

 

I really started hating the CW Academy classes because of the audio challenges.  SO much, that I eventually bailed out of Level 2.

 

73,

N1SFT

Craig Bailey

 

From: morserino@groups.io <morserino@groups.io> On Behalf Of Thomas Ruhmann via Groups.Io
Sent: Monday, September 30, 2019 13:40
To: morserino@groups.io
Subject: Re: [morserino] Direct Audio into the Mac

 

Hi folks,

I soldered a cable from the morserino TRRS input/output to the input of a external USB soundcard and get the sinus tone as input. Then I tried to reroute the tone to another soundcard output to hear it.

I´m actually in the first cw academy course and think also about piping in the cw tone directly to Zoom.

My problem is, that the latency of the output tone is to long - so there ist no hand-ear synchronicity possiible.

I´m using Windows 10 with VAC and Audio Repeater for routing. Any ideas to decrease the latency?

Best regards Thomas DG6UAX


--
_____
Craig Bailey
N1SFT
NH, USA

Thomas Ruhmann
 

Hi Craig,

I have a Music Mixer here for My guitars and mics. Will try to mix the Two Signals here.

73 Thomas DG6UAX 

Steve Witt
 

I was doing the Zoom thing for CW classes with the Long Island CW Club
last spring with both my voice and audio CW from my radio coupled into
my laptop microphone. It isn't great and if everyone doesn't mute
themselves there can be a lot of audio interference making copying the
desired code pretty frustrating. At the beginning of the summer, a
bunch of guys in that club had a group buy of Morserinos and I started
using that as a code practice oscillator instead of my radio. I
started a CW Academy Level 1 class this fall and in preparation for
that decided to try to improve my audio setup.

So I got a TRRS 'breakout' cable that separates the input and output
audio from the Morserino into TRS connectors and fed its output audio
into one input channel of an audio mixer. I got a headset with mic and
fed the mic output into another input channel of the audio mixer. I
use a Linux laptop in my shack and added a USB sound adapter to that
and fed the output of the audio mixer into the mic input of the sound
adapter and the output of the sound adapter to the headphone connector
of the headset. Zoom must be configured to use audio from the USB
sound adapter instead of the laptop's built-in sound card. I think
this works pretty well and I hope reduces any interference that my
stray audio adds to the Zoom teleconference.

The one issue that I have is that I don't get Morserino audio when I
send code in my headset. But I can hear my audio from the Morserino
through its speaker with my headset on well enough to send code well
[well, as well as I can send :)]. This probably wasn't the cheapest
solution and relies a little more on hardware than may be necessary,
but it's straightforward and seems to be working much better than
using the laptop's built-in sound interface. Another slight
complication was that I needed to get a microphone adapter that
provided the required DC voltage to the headset mic from the audio
mixer to get the headset mic to work properly. When I got the
Morserino I didn't imagine that its audio interface would be useful
for something like this.

73,
Steve K6ZX