(05-23-2020, 12:19 PM)SteveW Wrote: I play with a 4-piece band and we are using JamKazam to rehearse during lockdown. We all live within 10 miles of each other and are all using wired ethernet connections. The other 3 band members experience very little latency between them, but I seem to have a much greater Internet latency and one that varies wildly from about 20ms to over 100ms. I use the same ISP as 2 of the other band members. 

I am using a Behringer UM2 interface and a MacBook running Catalina. My interface latency is 10ms, using a frame size of 2ms. This is not great but within usable limits.

I have tried leaving JamKazam and doing an internet speed test, using one of the publicly-available test sites. Having done this a few times, the results are always around 20Mb/s downstream, 1.8Mb/s upstream and a ping latency of around 15ms (to a server in London, at least 70 miles away). This looks as though my internet connection is OK.

Lowering my outgoing bitrate to 128kbit/s improves things a little, but not sufficiently.

Can anyone please suggest what I might do to diagnose or fix this problem--or is it simply that there is a poor internet service in my neighbourhood?

Any suggestions much appreciated.
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First observation is that your local audio interface latency is way too high. By tweaking the frame size to 1 msec (Audio Booster in JK client), buffer size and recording frequency (ASIO driver) you should be able to achieve less than 4 msec. Don't settle for any more, period.

Forget doing PING tests. they use a dedicated IP protocol (ICMP) and aren't representative of your Internet latency. Speed tests are also usually a waste of time unless you have very little of it.

It's all about total latency...

You can check latency to known sites on the Internet using the LATENCY option at TESTMY.NET.  Use that to try and find a time of day where the Internet traffic congestion is the lowest. Then schedule your group at that time if you can.

I've got a group in the same boat as you folks. We all live within the same community and still have varying amounts of latency. It's a killer. Another thing that can help is the use of a drum machine or having your real drummer play to a click track and ignore the latency effects he hears from the rest of the band. Everyone else can just play to that beat. Works ok even with siginficant latency.

Report back with your results...

Stuart.

(05-25-2020, 10:23 AM)SteveW Wrote: Thanks for the reply, Stuart.

I have tried changing the frame size to 1ms but the audio just breaks up. 2ms is the lowest I can get with the Behringer interface. I am not using ASIO drivers as it is an Apple MacBook, so just using the default Apple drivers, which are not as highly tuned as the ASIO drivers would be (though I'm not sure the UM2 interface has got any specific ASIO drivers, anyway). I am currently using a sample rate of 44.1kHz, which was chosen because that's what other band members are using--I think there should be a speed advantage in all using the same sample rate. Maybe we could improve the latency a little by all using a higher rate. But I imagine that is going to shave off a few milliseconds, rather than cure the big problem of latency fluctuating from 20 to over 100ms.

Very good point about the ping tests. I had forgotten about ICMP.

I have tried Test.Net, as you suggest. This tells me my download speed is 16.5Mbit/s and upload 1.1Mbit/s. These are well below the quoted speeds of my ISP, so I think I am being short-changed by them at the moment. Will give them a call today.

We could give a click track a try. We have tried it in the past for other reasons and didn't get on very well with it, but I guess its a matter of practice and just getting used to it. Also we are using the lockdown to learn some new material, including building band arrangements of songs written by one of the band members, who is a prolific writer. Previously we found that the best results with a click track were when we knew the material very well and could really concentrate on the tightness of our performance. I think it would be least effective where we are trying out new ideas, improvising parts, trying different tempos, etc.

I am not sure my understanding of JamKazam is correct, but I am assuming that, if I set my outgoing bitrate to 256kbit/s, this is the rate for each audio channel, and that I have a separate audio channel for guitar and chat mic to each of the other participants in the session. (Is this correct?) If so, I would need an internet upstream bandwidth of 2 x 3 x 256 = 1536kbit/s. Add to this the overheads of TCP/IP and I am well over the capacity of my upstream connection. So, if this calculation is right, what I have seen as latency may just be the saturation of my internet connection. That would be consistent with what I have experienced: lowering my bitrate made an improvement and, in fact, the band's most successful practice was a day when, for reasons that remain a mystery, I could not get the instrument channel to work on JamKazam and ended up using the chat mic to pick up the guitar sound from from a combo amp, rather than having a dedicated guitar channel. So, on that occasion, I was only setting up a single mono channel to each of the band members.

Will report back after next session with the band.

Steve

I think the outgoing but rate encompasses the sum total of all your audio inputs. But your 1.1mb uplink speed is marginal but workable I think. I forgot that you can't use ASIO on the Mac since it uses Core Audio. But if you can adjust the recording frequency you should play with that to get the lowest latency you can. You and your session partners don't have to use the same. Playing with a drum machine or click track is mandatory in our experience in this environment. It's also good musical practice even though most of us would never do it when we were all in a room playing together.

Stuart.