Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

Choppy audio SmartSDR Mac

I'm a new Flex 6400 owner and really enjoying this radio. I've had great success with everything I've tried with it except for one thing.

When using SmartSDR for Mac I am getting choppy audio. I assumed that it might be my 8 year old Macbook Air, so I purchased a new Macbook Pro M1 but still have the issue. It actually seems worse with the newer Macbook (ugh).

I thought it might be the wireless, but my iOS devices and my Windows 10 and 11 laptops work just fine on WIreless.

I've tried setting the frame rates down to 2, BW to minimum, Low Bandwidth connection checked to no avail.

My wifi is an EERO Mesh system with all AP's hardwired to a managed gigabit switch.

I must be missing something..

Any suggestions?

Best regards,

David Wertz

Best Answer

  • W3RTZ
    W3RTZ Member ✭✭
    Answer ✓
    I finally found the issue!

    Location services on the Mac will cause a hiccup on Wifi. Most times it will be very infrequent, but if you are running any applications that query location services often (like every 10 seconds) it will be very obvious. I was running WiFiExplorer to help track down my "WiFi Issues" and it queries location services every 10 seconds.

    I disabled location services and the issue is completely gone.

    I was able to reproduce the issue by going to the apple menu->preferences->Security & Privacy->Location Services then toggling "Enable Location Services" On and Off.

    The instant I enable Location Services, SmartSDR audio stutters with a very consistent pattern. You can also see the effect it has on WiFi by running a ping and watching the latency go up for 2-3 pings.


  • AA5SH
    AA5SH Member ✭✭

    Hey David which audio is choppy is it the receive audio or transmit? If so what is the source for whichever is messing up? Just default speaker/mic or bluetooth headset?

    Does the display (waterfall/spectrum) act as you would expect when the audio is messing up?

    Just to eliminate the wireless (which doesn't sound like it is) could you try to hardwire your macbook for a quick test? You should be able to pick up a usb-c -> gig ethernet pretty cheap if you don't have one. I have had good luck with the monoprice brand from Amazon.

    I have not experienced issues with my MacBook Pro, iMac or my daughters M1 Mini or Intel Air. So hopefully you can get it sorted out.

    Michael, AA5SH

  • AA5SH
    AA5SH Member ✭✭

    The only reason I ask about the source is I purchased a pair Corsair wireless headphones and they quite often have a static sound but it also does it on other things like youtube or whatever. From what I read it was a bug in its driver I am waiting to get resolved.


  • W3RTZ
    W3RTZ Member ✭✭
    Hi Michael,

    It is the receive audio through the default speaker.

    The waterfall stutters at the same time as the audio stutter/chopiness. I have already hardwired my older Macbook Air and it works perfectly which led me to believe it might be the older wifi in that laptop. I used that as justification to buy a new MacBook Pro yesterday 😁 but having the same issue. 😒

    I ordered a USB-C hub with ethernet today to test on the new MB Pro. I should have that in a day or two to test.

    As another test I disconnected all of the networking in the house, setup a new router and AP as a test. Got the exact same thing with a Meraki MX firewall and AP. Seems to be only Wifi on my Macbooks.

    Thanks for the input!

    David, W3RTZ
  • KD0RC
    KD0RC Member, Super Elmer Moderator
    edited August 2021

    Hi David, another experiment to try is to plug your Mac directly into the radio, thus eliminating all of your networking gear (especially the WiFi). If you still have the issue, then I would recommend submitting a help desk ticket.

    If the direct connection solves the issue, then work through each piece of networking gear to determine the culprit. The most likely is WiFi. While WiFi often works great on streaming services like NetFlix, it is not well suited for the real-time data flow of an SDR.

    EDIT: Also, are you using the audio from the computer or directly from the speaker jack on the back of the radio? If the computer, try plugging in headphones or powered speakers into the back of the radio to see if that makes a difference.

  • W3RTZ
    W3RTZ Member ✭✭
    Hi Len,

    I'm using the audio directly from the laptop, not the speaker jack on the flex.

    I'm 100% sure it is only related to wireless connectivity. The puzzler is that it is ONLY with my MacBooks, not my Windows laptops or any of my iOS devices.

    I did determine that there is a pattern to it. It starts "stuttering" every 10 seconds for about 2 seconds.

    I am uploading a video that demonstrates the stuttering.


    David, W3RTZ
  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Excellent! Thanks for posting the solution, it really helps when others experience the same issue.

  • Ignacy
    Ignacy Member ✭✭

    Great discovery by David. I was puzzled why the choppy audio was only present on the Mac while being silky smooth in Windows.

    The next problem is finding why SmartCAT is often stuck. This is in contest setting with SmartSDR for MAC and N1MM/SmartCAT under Parallels/Windows. The CAT problem is related to the setup of serial ports and is not cured by FlexVSP repair or reinstallation.

    Ignacy NO9E

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    I turned off Location Services on my Macbook Pro and it seems to help, but I have had 1 or 2 audio hangups.

    BTW, when you do this, you turn off the ability to 'track your device' should you misplace it.


  • W3RTZ
    W3RTZ Member ✭✭
    Hi Mike,

    I've had zero latency issues on both my old Macbook Air and my new Pro since disabling the location services completely. Given that my Macs are my preferred machine I am really happy about this.

    I am doing some additional testing with the location services by re-enabling them as a whole and then disabling/re-enabling specific items under location services. So far, Siri & Dictation, Location-Based Suggestions, Significant Locations are the only ones that I can reproduce the problem with consistently.

    I thought that I had narrowed it down to a specific location service entry, but then it popped up again. However, having it stutter a couple times an hour is far better than every 10 seconds.

    I'll continue to report my findings via this thread for anyone that is interested.

    David, W3RTZ
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    Thanks David

    That is good work and an example of identifying the solution even when it seems like it isn't related to the symptom.

    Marcus has a note about this in the manual for SmartSDR for iOS but he never thought it would be an issue with SmartSDR for MAC.

    I just had a QSO on 40M using SmartSDR for MAC and my cool USB Foot switch using my Podcasting Mic. It worked really well.