I have Jamulus issues all of a sudden...

[noddyspuncture]

Hi folks,

Hoping someone here might be able to help..? I just started getting Jamulus issues a few weeks ago.
Everything has been great for ages... years even. Then all of a sudden Jamulus became un-useable..!

I started getting garble audio for long durations and it seemed to cycle/oscillate...?
Everything would sound like a Dalek and for long periods of time and my delay would be in the red - whereas before I was getting 20 to 30Ms for long periods of time and clean audio before hearing the odd pop or glitch.

I checked my broadband speed and found my fibre to the house was down at about 80Mbs. My package was 150Mbps - but apparently only 75 was 'guaranteed'. (I used to get 74Mbps with my copper cable telephone line before I had fibre installed.)

So I called my ISP and have now upgraded to 910Mbps (445 guaranteed) and when I do a speed check I am actually seeing as much as 1,200 Mbps at times - but I am still getting the garbled cycling... once about every 10 - 15 seconds but now the garbled audio only lasts about a second, but it is still frustrating and makes it un-usable. During the garbling, my delay jumps up to around 300Ms for a second or so... but with annoying regularity. PreviouslyI used to get the odd glitch and it was totally random... but the repetitiveness of this makes it even more annoying.

So I know it's not a speed issue as the upgrade has made my connection 12 to 15 time faster.
It is definitely me because no matter where I connect - I can 'server hop' - and the issue stays with me.

Would anyone know what I could do to try and get it back to like it was before...?

Thanks.
Tom

[dcorson-ticino-com]

Unfortunately it is certainly your ISP.
Broadband speed is only one parameter that can cause problems.
Others are jitter and packet loss.
Even your 75MBps guaranteed rate should be way enough as long as you are running just a client and not a server.
But if the packets are not sent at a constant rate you will have problems.
Do you have the possibility to try out another provider? Even a connection through a cell phone could give you a hint.
With that you may have a big delay, but if the jitter is low the sound should be fine.
Sorry I don't have better news, but maybe another call to your ISP talking about jitter could help.
Don

[pljones]

Our "80Mbps / 20Mbps" (actual 72 / 18) has degraded over the last couple of weeks to "13Mbps / 18Mbps" -- just after they announced FTTP. They probably think we'll take a 100Mbps package for the same price we were getting 72Mbps (we used to get 90Mbps regularly...).

So yes, blame your ISP.

[noddyspuncture]

Thanks for the replies guys.
The thing is, I went with this new ISP a while back, had fibre installed to the house and got the 150Mbs package. I regularly checked it and I was actually getting 150. And I had no issues back then. All of a sudden the issues started and when I checked my speed I could see it was much lower. So I decided to upgrade, assuming it was speed related and I think I am now in a contract and have to stay with them for a period. I'd need to look into it.

Anyway, I have a question... is the 'jitter' and 'packet loss' something the ISP can tweak to my requirements..? I suppose I could ask to talk to their technical department and explain it all to them.... but I didn't know ISP's did their thing in different ways and one might be better for us than another.
Cheers.

[pljones]

Your ISP is only responsible for the connection from you to them. They've no control over what the rest of the planet is doing. I was going to type "unfortunately" there... but that's probably not the right word!

Oh, and I did just find out, after we finally got onto our ISP... It wasn't them, it was me. I'd obviously been checking the QoS settings on the router and somehow reset a field that really did not want touching (from unlimited to "17"). Changing that magically unblocked the connection. Not directly the QoS settings but the overall throughput. I'd say I'd never intentionally touched the fields -- but both "upload" and "download" caps were set. Can't think why I thought that was a good idea.

[noddyspuncture]

Hello again, well... after lengthy conversations with my ISP and I even had them call me back the next day... they asked me to do the ping test on my computer and it always reports back "zero % packet loss". So my question is - if it's not packet loss the what's my next step...?

[pljones]

Packet loss has nothing to do with throughput. If Jamulus isn't getting audio round tripped from Client to Server and back in time to keep your buffers full, you'll get glitches. If the ISP asked for a ping test to diagnose that, they don't really understand the problem.

[noddyspuncture]

OK - but then I don't understand. If it's not packet loss then what is my problem...? And should the ISP be able to sort it...?

[dcorson-ticino-com]

The problem is not the speed with which the packets are sent, but the regularity with which they are sent.
A speed of 10Mbps should be good for Jamulus assuming that the packets are sent regularly and not in bunches.
Your problem is probably that your ISP is sending, for example, bunches of packets very quickly and then for a while nothing.
It looks like a good transmission rate, but any particular packet can arrive very late.
So the packets are not lost, they are just not arriving in time.
That is what causes jitter.
Imagine the jitter buffer has two packets left, but the sender waits another 10 packet times before sending 15 packets very quickly.
The speed is good, but during 8 packet times you would be missing the next packets.
Neither the broadband speed nor the ping time is a useful measure for this problem.
It is difficult to explain, but unfortunately the only instance that can solve it is your provider.

[noddyspuncture]

OK, thanks for the detailed explanation. I'll tell them - they are calling me again.
So is this something they can tweak and change for me or am I stuck with it and the only answer would be to leave them and try another ISP...?

[pljones]

And it might not be your provider. It could be the next link away. Or the next. Or the next... etc, all the way around the planet and back.

[ann0see]

You could try a VPN and find out if it makes things better. Usually it does not make things better but rather worse.

[mcfnord]

Sorry if you tried this already, but if you have Small Network Buffers on, turn it off. See if that helps.

My experience is that wireless connections (one of my ISPs has a wireless device from my house to some nearby radio tower) can perform worse when Small Network Buffers is on.

Perhaps your ISP has added high-speed wireless hops that change UDP packet ordering in a new way.

Not sure why, but it was a configuration I had to change after many years.

[noddyspuncture]

Yes, I have tried every possible combination of every available setting.
Nothing improves it... and some variations make it worse.

[ann0see]

A shoot in the dark: do you use fiber? Is it a passive optical network (PON)?

[noddyspuncture]

I have fibre to the house.. not sure what PON is...?
How do I find out and are you saying PON isn't Jamulus friendly..?

[ann0see]

I have no proof that a PON based structure leads to issues with Jamulus. PON means that you share the link to some extent with others. I could imagine if there's time slicing anywhere, this could explain the issue.

https://resources.l-p.com/knowledge-center/aon-vs-pon-optical-networks

My personal purely technical (naive) view point is that PON - especially with time slicing - is not clean unless sharing is e.g frequently based and never interrupted. (No need for you to think too much about this unless you understand this level of detail)

[ann0see]

What you could actually do would to check (research via a search engine) which technology your ISP uses. If it's AON, (XGS) PON,...

[noddyspuncture]

Hi again folks,

So I am still struggling with this connection problem.
We had a rehearsal tonight and it was horrendous... basically un-useable..! And it was so good just some weeks ago.

Anyway, I have notice a symptom and thought I'd share it in case it points to anything...?

I have noticed that although I am hearing myself coming back regularly distorting and crunching with a high ping and delay and lots of jitter... I am hearing the other guys perfectly clearly at the same time. They didn't have any issues over the two hours we were on.

So it looks like it's only 'one way'... my 'return' or what is coming back is fine. Looks like it's just what I am sending that gets corrupted...!?

Does this narrow it down any...?

[pljones]

Can you just clarify:

• You hear yourself distorted
• If you MUTE your mixer channel, you can't hear yourself and everyone else sounds good
• Everyone hears you and you sound good to them

Is that right?

• If you bypass the Server -- i.e. connect to an empty server and use the Mute Myself button (but keep your mixer channel unmuted) -- that sounds distorted still?
• How about if you don't run your sound through Jamulus at all?

[noddyspuncture]

Yes, everyone else sounds excellent.
No, when I hear the garbled distortion and crunching everyone else also hears it the same.

My sound at the source, ie: my mixer, sounds fine... it is just what periodically but regularly comes back from Jamulus that sounds distorted.

I have my ISP calling me again tomorrow.

[pljones]

OK, still haven't narrowed it down like I was trying to.

You've a hardware mixer. Ignore that completely. Leave it sending the audio into your computer.

You've something Jamulus is getting audio input from and sending audio output to -- in Settings.

Can you confirm that if you take the following steps, you hear NO distortion:

• Connect to an empty Server (doesn't matter what server, probably one of the genre Directories with only one slot is best - your audio isn't going to the Server anyway)
• Turn on "Mute Myself" on the left side and leave your fader in the Jamulus mixer unmuted

And you've confirmed that if you turn off "Mute Myself" (and change nothing else) you start hearing yourself distorted.

[mcfnord]

I don't think anyone has mentioned: maybe some software on your computer is pushing a lot of bits. Is there a different computer you could try? Have you looked at a Task Manager for network throughout?

[noddyspuncture]

I have Jamulus on four separate Mac computers and they are all doing the exact same thing...!

[mcfnord]

The detail that jumps out to me: your outgoing audio corrupts while incoming stays clean, it hits all four Macs, and it cycles on a regular 10–15s beat. That combination is useful — it rules out any single machine or audio interface, and it points at the shared upload path (Mac → router → ONT → ISP) rather than bandwidth, which you've already thoroughly disproven.

A few things I'd try, roughly in order of effort:

1. Hardwire one Mac via Ethernet and test. A regular ~10–15s stall is the classic signature of macOS WiFi background scanning — the radio briefly scans for other access points on a timer and stalls outbound packets. If any of your Macs are on WiFi, this alone can produce exactly what you're describing. Ethernet takes it out of the equation.

2. Run a bufferbloat test (the Waveform one is easy). Your speed upgrade came with new hardware, and a new ONT/router can buffer the upload direction worse than the old one — which fits the one-way symptom. If upload latency-under-load spikes, turn on SQM / fq_codel / "smart queue" on the router and cap upstream to ~90%.

3. Confirm it's the network with a parallel ping. While Jamulus is glitching, run ping -i 0.2 <server address> in a terminal and watch whether the latency spikes line up with the audio dropouts. If they do, it's the network, and you've localized it.

4. The killer isolation test: run Jamulus over a phone hotspot for a few minutes. If it's clean on cellular, your ISP/router is confirmed as the cause; if it still glitches, we look back at the Macs.

If you'd like harder data than the client shows, I run some Jamulus servers with packet-level instrumentation — if you tell me your rough location I can point you at a nearby one and measure your upstream's jitter and loss directly from the server side. That'll say definitively whether it's jitter, packet loss, or bursty sending, which is hard to see from the client end.

[noddyspuncture]

Thank you for the detailed analogy and suggestions.
It is all a bit technical for me but I shall run it by a much more technically savvy friend and see what we find.
I am located in North West UK - near to Manchester.
By the way, I always hard wire when using Jamulus and never use WiFI.