Using KEF LS50 Wireless II with a Subwoofer

Happy to hear!

Just for completeness, by part 3, I mean to follow the pop up that says set the sub volume to 3pm. The aim of the setting is for a smooth handover not just in frequency, but to keep the volume balanced as well. But it is a starting point, every room and taste is different in regards to presentation of the low end.

I had a pair of SVS subs working well with my Mk2’s. Ben’s advice is how I had mine set up. The advice should work for any sub.

Set the sub for the frequency you want it to start working at, say 50hz.
Set the Kef’s sub low pass frequency for something higher than that, say 100hz

The subs will turn on much sooner but will still only reproduce the frequencies that you want.

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Thanks, Ben, that makes sense now. I may well turn the sub volume down [to 3pm on the dial] and see if it still works as before.

Now, can I ask you to put forward just one more change to the way in which the KC-62 interacts with the LS50 WII please?

Simply put, can Kef add a button to the excellent control App which says “Wake up the sub-woofer” and literally pings a signal of some sort to it that can do just that?

I don’t know how that would work technically, or even if it would require a firmware change [probably so], but having to blast the volume momentarily up to around 65-70 on Roon just to get the KC-62 working every time I start playing a session is not only inconvenient but also - literally - damaging my hearing as I already have tinnitus in both ears!

I appreciate briefly playing material with a heavy bass content and/or a loud volume will do it, but that is just as inconvenient really.

I’d really be very grateful indeed if you could put that suggestion forward to your colleagues at Kef.
Thank you once again. Keep up the great work!

I have the same problem, I listen to music during evening/night and I have to enjoy music without sub :frowning:
I’ve put the gain to +10db and lowered the sub volume to compensate (also using room correction) which helped but it’s still not enough…
Perhaps updating the app to allow +20db gain on sub is possible? This would seem as easiest solution since the sub fw is not upgradeable as far as I’m aware and user could always dial back the gain on the volume knob/room calibration/EQ.

I’ll forward the suggestions - I can at least promise they will be looked at in regards to feasibility.

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Thanks, Ben
That’s much appreciated.

The sound level from the LS50 WII speakers via ethernet cable is so much higher now. I think I will do some a/b comparisons of the sound quality (cable vs wireless) but from what I hear right now, Roon Ready status has been a major plus for your kit. Well done you :grin:

Hey @Ben_Hagens

Just got home and tried the your settings – all appears to be working fine and sounding great. Thanks! (Same goes for the RoonReady FW, but no surprise there… ;-)).

Given the highpass at 70Hz – am I right in thinking the Bass Extension setting (Less/Standard/Extra) doesn’t really matter anymore?

You would be correct, HPF overrides.

You could consider the bass extension option to be preset HPFs for LS50WII when a sub isn’t being used (the idea is that, in a smaller room, room gain starts at a higher frequency, so the bass rolls off higher to compensate for what you gain from the room)



Quick update: i have a list of issues with the kc62 that i am sharing. Link to follow.

Kef is working in a firmware update to fix the pop in rca out. Info below. Quick q: is there a way that users can update firmware themselves or does this require Kef to step in?



The engineering team will be investigating the KC62 to make sure it is not sending a signal out after going into standby. If for some reason this is happening in the KC62 you could experience the noise you have described. That would also mean it would happen in a new unit.

Before we move forward with getting you a replacement unit let’s wait for confirmation from engineering.

Thank you,
Fred Cobb

The development team has confirmed that the issue is due to the KC62. They are currently working on firmware to fix this issue.

Thank you,
Fred Cobb

Here is the link:

Hi Pascal,

I’ll be able to give more info as I receive it, I’m not sure what any rollout would look like as of yet.

I confess that this auto-standby issue is causing me to hold back on my plan to get a KC62. For the people who have implemented Ben’s suggested fix to essentially shift the crossover from the LS50W to the KC62 how is that working out for you? I tend to listen to my LS50W (currently v1 but might upgrade to v2 later this year) at about 38 to 40 on the Roon volume setting so not at all loud.

Also for Ben a couple of questions…

1 - Is there some level of firmware control over the level of signal coming into the LTE port at which the KC62 comes out of and goes back into standby or is that controlled by analog circuitry to detect the threshold so not adjustable short of actually changing components on the PCB? Essentially I’m asking if this issue might ever be able to be addressed via a firmware update, maybe with an option for the user to select the sensitivity themselves or even disable auto-standby altogether. Maybe disabling it altogether wouldn’t be great because as far as I can tell there is no remote for the KC62 which is a bit of a shame at least for me because I use a universal remote so it would be no big deal for me to add KC-62 power-on/off commands to my power-on/off routines on my remote but if the KC62 has no IR capability then clearly that is impossible.

2 - If the KC62 is fed via the wireless connection kit is that handled any differently? I assume (maybe wrongly) that the audio is transmitted between sender and receiver digitally but is it then converted to analogue in the receiver so that the KC62 still sees an analog signal as it does with the LTE input or does that socket on the back of the KC62 see the digital signal? If the latter then might a firmware update be possible on the wireless sub connection even if it’s not possible on the LTE input?

In one word: great – it’s a whole different ballgame. The sub now auto wakes even with light use and stays awake whenever music is playing. I have only had it fall to sleep with low volume, talk-only TV and very low-volume classical chamber music – as it should. I play at about the same volumes as you mention.


I have collected most know issues + remediation (if any) + Kef’s response here >> Link << I have enabled comments so anyone can provide these.

In addition you need to be aware of the 2 following things Kef is/has been working on:

  1. inverted polarity at sub out - this was the case in the initial production run and has apparently been fixed in later production runs
  2. pop/signal send on RCA-out around 10 mins after this sub goes to standby. Kef is working on a firmware fix.

That being said: i really would like Kef to confirm that they are working on a fix as mentioned work arounds are a bit odd for a sub at this price level. Can anyone @Kef please confirm?

Note that i have already ordered a KC62 + KW1 module but holding off delivery as i rather not send it back to get the firmware updated/fixed/whatever have you…

At Julian: no-one has been able to confirm whether this issue gets solved using a KW1. I know 1 user who has this combination - i’ll check with him to see if got any results.

@Kef employees / @Ben_Hagens - we would really like to have a platform supported by Kef to report and discuss these issues (and fixes/workarounds) as it is now dispersed across several social media platforms - i believe this will help both Kef as well as their customers

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Good morning/afternoon Ben,

Rollout would depend on whether the KC62 is user-updateable - that would greatly simply things. Unfortunately i do not see a USB port or similar. Would you be able to shed some light on this matter?

Re the KC62 i do have serious concerns - it’s a wonderful product (i have one on order and more might follow) but there are also some issues (wake-up issues, pop, inverted polarity) that owners might find unaccepable at this price point and some of them are returning their KC62.

I guess marketing or engineering might need to step in here and issue a formal statement on how to address/solve these problems (or provide a draft timeline).

Just to be clear: Kef makes wonderful products - please keep doing so - and i don’t mind spending a small fortune on them - And although we all understand that every product has it’s issues communications from Kef must really improve here.

Hi Pascal,

I can confirm that the reported issues are being worked on as a matter of urgency, and I will update here when I can. Don’t take this as me being short, after all I can only provide information that I have.

Hi Ben,

No problem and i fully understand. I’ll wait until further update from your side.



Hi Ben thanks for all your support on here. I just got a single KC62 to pair with my new LS50 IIs. The settings as you suggested seem to work very well and sound is awesome. I do have one question. Pascal noted in his issues list and I just read form another user that the phase needs to be inverted when switched to MANUAL instead of LFE.

Can you please confirm if this is accurate, does the phase need to be inverted when running in MANUAL?


Hi Julian,

I checked with the other owner - he did not yet tried the KC62 with the KW1 - so no update yet (unfortunately).



Hi @Ben_Hagens — I appreciate you being active on this thread.

I am the owner of the LS50 Metas, one KC62, and a miniDSP device.

Your instructions for LS50WII owners to switch from LFE to Manual from post #17 are clear to me. I have two follow-up questions though:

First, is it a problem to tackle this problem slightly differently? Ideally I would like to 1) set the sub to Manual mode, 2) set the sub chassis LPF dial all the way up to 140hz, and 3) on my miniDSP to set the LPF to a conventional Linkwitz-Riley 24db/octave slope at 80hz? I would be using both RCA outputs of my miniDSP into both RCA inputs on the KC62.

It is my hope that this would address the issue of lack of LFE mode sensitivity to wake-up, and give me control over the LPF exactly the way I want it on the miniDSP rather than on the sub chassis like in your method. Your official method already has cascading filters, with the 140hz LPF on the output of the LS50WII being fed into the 70hz LPF of the KC62. My suggested solution would have the 80hz LPF from the miniDSP first, followed by the 140hz LPF on the KC62.

Second, can you please disclose the type and slope of the default LPF and HPF crossovers that KEF is using for the LS50WII and KC62? I think it’s only fair to your Meta+KC62 customers to allow us to set our speakers to your exact specifications, especially for the Metas since there is no way for us to replicate your HPF crossover unless we know the type (LR or BW) and slope. I don’t see any reason why that should be proprietary info.

I hope I’ve been clear here. Thank you!