Northern Utah WebSDR
Fixing audio problems when using the Chrome
and Safari browsers
If you are using the Safari Browser, you may have noticed a recent
problem in which you get no audio - even after pressing the "Audio
Because I don't use Safari, it didn't affect me - and I couldn't test
it, either. Fortunately, Stan sent me the following note:
I enjoy your SDR
but a couple of weeks ago I had no audio on my Mac Safari ...
apparently after an update. After a couple of weeks trying to figure
out why, I found on Safari v12 the following settings that
restored the audio:
-> Preferences -> Websites -> AutoPlay =
Allow All Auto-Play
Don't know if
you've had this question, but it worked for me.
Thanks for the heads up!
Important note: There are new problems with the Chrome browser
as of early September, 2018!
It would appear that a very
recent update to the Chrome web browser (e.g. 69.0.3497.81) has
another problem: Very loud white noise when the WebSDR starts up, often accompanied with a blank waterfall.
A quick "fix" for this problem may be to toggle the mute button just below the S-meter (e.g. mute, then un-mute). It has been reported that this usually works - at least for a while.
Other than toggling the mute button below the S-meter, there's no known work-around - yet -
so it's recommended that you use a different
browser if this is a recurring problem for you: Firefox works well and is recommended!
If you hear NO
audio in Chrome:
If there is a button on the
WebSDR interface that says "Chrome Audio Start", press it!
you land on
this or another WebSDR - and you are using the "Chrome" browser, but
hear no audio - you may have to enable it.
did they do this?
The reason for this is to require
that the users click on something to
enable multi-media (audio,
to avoid annoying sites from blasting you with unwanted audio - and,
possibly, protect against something
nefarious. It is incumbent on those running web sites with
built-in audio to
add code to detect that the user is running Chrome and provide the
button to be pressed, but if this code is not
present, the user may have to jump through the hoops (below) to figure
out how to re-enable audio.
Because WebSDR use web-based audio, it, too, may be affected by this.
There are reports that after the initial release of Chrome
version 66 that required one to "click" or otherwise enable audio, this
requirement may have been rolled back a bit - but it will probably come
back again in the future.
Chrome on a mobile device
As you may have noticed, when you are using a mobile device such as a
phone or a tablet, you are given the option to use the "mobile" version
of the WebSDR interface. When you do this, a "lightweight"
version of the web page appears with fewer options - but streamlined to
work better on these types of devices.
Support for Chrome was recently added - which also requires one to
press the "Audio Start" button - and although it seems to work, it may
One issue with the Chrome+Mobile option is that when the screen goes
dark, the audio may also stop: We are looking at ways to work
If you choose to use Chrome with the "normal" Web page, there are
reports that the audio will stutter and drop out due to the
browser/processor providing enough time to properly service the audio
routines. If this happens, there are two options:
- Disable the waterfall by clicking the "blind" button above and to the
left of the waterfall. You
may need to click on the "one band" and then back to the "blind" button
for it to take effect.
- Use a different browser. It would seem that
the Firefox browser works
reliably on (pretty
much) all mobile devices - and it seems to work properly
if you run either the Mobile or "Full" versions of the WebSDR -
although the battery consumption of the mobile version may be slightly
lower, particularly if you turn off the waterfall using the "stop
Before you do anything else, check:
Did you mute
the audio yourself? Before you go any farther,
you may have muted the audio in one (or more) of
Do you get audio on other
programs/web sites using Chrome? If
so, not all of the suggestions below may apply.
- Make sure that the "Mute" check-box near the
volume control on
the WebSDR user interface is not checked.
- You accidentally hit the "mute" button on your
multimedia keyboard - if you have one.
- You have somehow muted your audio on your
computer's audio/mixing control panel.
- You turned down/off your speakers.
- Did you mute the site in Chrome itself?
shows where to find this control - and how to
ruled out operator error, read on.
next thing to try: Click the "Button"
Increasingly, some web browsers are requiring the user to "activate"
the multimedia (audio/video) if a site has it - and Chrome is no
exception. To do this, the code on the web site itself needs
be modified to provide this button - but not all web sites have this.
We have added this button on the Northern
Utah WebSDR - so you need only click on the button that says "Chrome audio start".
You may need to do this every time you
visit the WebSDR, though - and again, this button
may not be present on every WebSDR. Other
WebSDRs may or may not have a similar button.
#1 - the most reliable:
Use a different browser such as FireFox, Seamonkey or PaleMoon to name
but a few.
It is possible that these other browsers will eventually follow suit in
disabling audio by default, but we'll deal with that if/when it happens.
suggestions below may work to enable sound in Chrome with the WebSDR,
but reports indicate that it may not be consistent - or continue to
work after software updates.
Check to see if the browser tab shows a tiny "muted
speaker" icon. If it does, right click
on the muted speaker to open up a dialog box: If you see
"Unmute site", click on it. If it says "Mute site", it is not
Chrome "remembers" if you muted the site last time
visited it which means that even if you reboot or restart Chrome, it will still be muted!
Disable the security
Chrome so that audio works on all web sites that have it, just like it
did before - this option seems to be the most reliable if
the site doesn't have a "start" button of some sort:
- Open up Chrome.
- At the top of the screen where you would type in a URL (but NOT
in a search bar that
you may have installed) type in EXACTLY: " chrome://flags/#autoplay-policy
" (e.g. the stuff inside the
quotes). You can cut and paste this if you like.
- A page will open up and the first item will be "Autoplay
Policy" - See Figure 2, to the right.
- Click on the drop-down on the right side of the screen and
select the option that includes the text "No User Gesture Is Required".
- This change will not take effect until you restart the
browser: Click "Relaunch
on the bottom-right corner of the window.)
- You may get some sort of warning along the lines of
EXPERIMENTAL FEATURES AHEAD! By enabling these features, you could lose
browser data or compromise your security or privacy. Enabled features
apply to all users of this browser."
Accept these changes.
- If you don't wish to accept these changes, try a
different browser (e.g.
FireFox, SeaMonkey, PaleMoon).
- The down-side of doing this is that if you visit a site
with annoying audio/video, it may automatically start.
Enable the sound on the browser for that specific web
While this option may be
present on Windows-based computers, it may not be available on other
It also seems that these settings may not "stick" and quit working
and/or the option disappears entirely after it is used. If
is the case, use work-around #2, above.
- At the top of the screen is an address bar (where you would type the URL).
At the far right of this you will see a small icon of a
speaker with a red "X" next to it: Right-click
on this icon and you will get a box that says something like "Sound was
muted on this
page" and a selection that allow you to "Always enable sound
page": Choose that one.
- You will need
to do this for each
and every different WebSDR server that you visit - and
this includes each of the separate Northern Utah WebSDRs.
- There is also a "Manage"
button on this same pop-up box that
you can press that allows you to select how the various sites' audio
should be treated.
did you fix the "audio start" problem with Chrome on the Northern Utah WebSDR?"
Ideally, we'd like to have the audio in Chrome auto-start without the
user having to press a button - but an initial "read" of the issue
would seem to indicate that if the above steps don't work, you will
have to press a button every time. If this is the case - and
find it a pain to do - I would suggest the use of the FireFox or Pale
Moon web browsers.
Do you run a WebSDR system and wish to know how to modify
the code to allow Chrome to work? Go to the Chrome
WebSDR fix page for details.
A screen shot of what needs to be changed to always enable
"auto play" to get WebSDR audio in Chrome.
Select the "User gesture is required..." option (highlighted) and
then click the "Relaunch Now" button at the bottom of the screen (not shown) to
restart the browser.
Click on the image for a full-sized version.
As noted above, there's no known permanent fix (yet)
for the "white noise" problem that may occur when you first start the
WebSDR in Chrome: It's believed to be some sort of pointer/array
corruption issue in the browser-run code that decompresses the
waterfall and audio streams from the WebSDR.
- For general information about this WebSDR, go to the About
- For answers to possible questions, visit the FAQ
- For more information about the WebSDR project in general -
including information about other WebSDR servers worldwide and
additional technical information - go to http://www.websdr.org
Go to the Northern Utah WebSDR