Problem with Sample Rate Conversion on KEF LS50w

inbox4 · June 20, 2019, 10:47am

I tried upsampling within the DSP settings and it didn’t go well. (I am using the latest version of Roon)

If I turn on sample rate conversion and choose either Max PCM Rate or Max PCM Rate (Power of 2), I get no music and low level crackling. If I go to the custom settings and set 44.1 to be converted to 88.2, this works but no higher conversion will. This was tried with a 44.1 ALAC file. Roon is recognising the speakers in device settings as having 24/192 capabilities.

My Core is a 2012 Mac mini i7 2.3 server connected to the router via ethernet. The LS50w are connected to the network via wifi but I get a fast, strong wifi signal to the speaker location.

I want to continue to use wifi rather than using additional ethernet cables to the speakers.

Are you able to give me any pointers as to why anything over 88.2 is causing this problem?

Thanks and regards.

Ratbert · June 20, 2019, 12:17pm

As per Kefs website

What is the sampling rate of the LS50W?
Depending on the source, the LS50W uses a sample rate of 192kHz (for USB Type-B audio) or 96kHz for the optical TOSLINK input.

I believe WiFi has the same or similar restrictions I cannot currently find the relevant document.

inbox4 · June 20, 2019, 12:26pm

Thanks for your thoughts.

I’m not using any physical inputs, just WiFi.

My streaming speeds are either 60mbps or 210mbps depending on whether the speakers are connecting to the 2.4 or 5ghz networks.

I use Google WiFi so have no control over which band is used.

Surely either of those speeds should be fast enough for 2 channel 24/192 audio?

Ratbert · June 20, 2019, 12:32pm

That assumes the WiFi input supports 192? maybe it does I am not sure, as a quick test connect a temporary lan cable from your router to the LS50w’s and see what resolution Roon sends, I have just tried it on mine and 192 streams as 192 via a lan cable.

noris · June 20, 2019, 5:18pm

Hi @inbox4,

I would give the Ethernet cable a try because even as a temporary test, it would give us a great data point. We also have some additional suggestions in our KEF Troubleshooting Documentation.

Christopher_Boehm · June 20, 2019, 6:32pm

Same issue for me. Upsampling beyond 88 is a no go.

inbox4 · June 20, 2019, 7:34pm

Have you been able to try a directly connected Ethernet cable? If so, did it solve the issue?

Riviera_Bluesman · June 21, 2019, 1:29pm

I am currently listening to an internet radio station by streaming over WiFi from my Nucleus server to my KEF LS50W’s. I just changed the upsampling to 192 kHz and it’s working just fine.

Doesn’t solve the problem, but I can confirm that upsampling via Roon to 192 kHz over WiFi to the LS50W’s does in fact work.

I had been listening by upsampling to 88.2 kHz before reading this thread, and can honestly say that I don’t hear any audible difference bumping it up to 192 kHz. YMMV of course…

inbox4 · June 21, 2019, 2:16pm

Thanks for the feedback. Do you know what sort of wifi speed you’re getting at your speaker location?

inbox4 · June 21, 2019, 2:39pm

Could it be that 2012 processor isn’t up to the task?

It is an 2.3GHz i7 though.

Riviera_Bluesman · June 21, 2019, 3:32pm

Yes, my download speed is 70-72 mbps. I have an eero mesh network in my home.

Dan_Brown · June 23, 2019, 12:35pm

I stream wirelessly to my Kefs at 192/24, no problems. However… my speakers are only a metre or so from my router and, I chose a WiFi channel on my router that is free of congestion from neighbours.

To do this, I used “iStumbler” on a Mac to see what channels all my neighbours were on. Then I manually logged into my router and chose a different channel.

You can use “NetStumbler” on a PC to do a scan.

You say you use “Google WiFi” so you can’t choose whether you’re on 5GHz or 2.4, I guess you can’t choose channel either then?

What Router do you have? How come you can’t log into it?

inbox4 · June 23, 2019, 12:53pm

Interesting. Thanks for your feedback.

I use a Virgin router that was supplied free with my cable broadband. Google wifi selects band and channel automatically. I don’t think I can manually change either.

I could try Ethernet as a test but it’s a pain and I’d have to use it via power line from an inconvenient position.

Dan_Brown · June 23, 2019, 4:02pm

I’ve got a Virgin SuperHub Router.

You can access it from a web browser on a connected computer. It can usually be found at 192.168.0.1

I’ll have a look when I get home and do you some screenshots if you’re struggling.

Dan_Brown · June 23, 2019, 4:04pm

I’m not sure what you mean by this. Where does “Google WiFi” reside?

Do you have a PC or a Mac that you use at home?

inbox4 · June 23, 2019, 4:20pm

I meant, I cannot chose the channel or whether to use the 5 or 2.4ghz networks. Google wifi manages all this independently.

I have 3 google wifi base stations dotted around the house but a long way from the hifi.

I do have a pc.

Dan_Brown · June 23, 2019, 4:46pm

Ah ok… so your Virgin Hub is just being used as a modem and Ethernet router, not providing Wi-Fi

In that case you need to find a way of logging in to the Google Wi-Fi base stations maybe…?

Might be worth doing a netstumble and see what WiFi channels are being used locally. Then, if you can find a way to manually control the Googles it may help.

Have you thought of maybe getting another google base station and putting it nearer to the Kefs?

Dan_Brown · June 23, 2019, 5:22pm

Hmm… I’ve had a quick Google of the Google Wifi system… seems you can’t log into it.

Looks like you might have to go down the power line route.

Couple of things you could try…

Hard wiring the google puck closest to the virgin router if you haven’t already done so.

Setting up the Virgin Router to only use 2.4 GHz. 2.4 GHz travels through walls better than 5G. You may then be able to log into the Kefs and force them to log into the virgin WiFi signal rather than the Google WiFi signal.

You can log into the Kefs by typing in their assigned IP address.

Just thoughts really… these ideas may or may not work!!

inbox4 · June 23, 2019, 6:37pm

Thanks for your effort and suggestions. I think Ethernet over power line is the best start. I’m happy with 44.1 but it would be reassuring to see 192 work and see if it sounds any different.

Dan_Brown · June 24, 2019, 12:30am

You’re welcome.

I use up-sampling all the time. I’ve convinced myself it sounds smoother and more ‘Analogue’ like.

I stumbled across a post that suggested up-sampling MQA on a non-MQA DAC improved things so I tried it and I felt it improved CD quality masters as well. It’s subtle, but it’s there!

I use Smooth/Minimum phase up-sampling to 192/24 and I think the Kefs sound, as I say… smoother and more analogue like, with less of a clinical ‘edge’ if you see what I mean?

Anyway… worth a try.

I also have a few hundred gigs worth of actual ‘HD’ recordings, some DSD which get sampled to 192/24. They sound fine.