new KEF KC62 dual 6.5" subwoofer

[KMO]

Hey guys what’s the right frequency to crossover kc62 with LS50 meta?

With the H190, you're not actually crossing over the signal, right? The speakers will be full-range, so you're just filling in bass below the speakers' natural extension.

If running with ports open, then you'd want the LPF set low to maybe something like 45Hz, as that's where the LS50s' bass dives. But be aware that as discussed over in this forum, the LPF knob can be a bit weird right down the bottom. It might be hard to actually get 45Hz, rather than 40Hz or 50Hz.

You could bung the ports so they start dropping off higher, around 100Hz, but the drop-off is slow - possibly too slow to integrate well with the sub's 24dB LPF. Port bunging works well in conjunction with a receiver's asymmetric 24db LPF/12dB HPF crossover, to create an overall symmetric 24dB crossover, but probably not without that 12dB HPF. Could try it though.

Here are my in-room response measurements, showing the LS50 Meta's bass extension with and without bungs.

See also the LS50 Meta thread, which has some discussion of subwoofer integration.

 

[nothingman]

Gonna be hard to get good integration without being able to run a HPF along with the LPF, and without any sort of EQ or time alignment. The KEF recommended lpf for the W2 is 45hz and that’s with a 70hz hpf. You’re have to shoot pretty low on the lpf to prevent a big response hump.

 

[RiseFall]

what’s the right frequency to crossover kc62 with LS50 meta?

I use:

Set LPF with LR 4th order at 55Hz
Set HPF with BW 2nd order at 90Hz
LFE on KC62

But still experimenting.

 

[Jeschiotz]

can I ask some basic questions here?
Got Minidsp SHD connected to a tape in/out on my Luxman amp which is driving a set of Sonusfaber Guarneri Evo`s
My idea is that I find a good spot for the subwoofer using REW without using Dirac or any delays settings in the Minidsp. What confuses me is the different settings on the KEF.Shall I use 2 of the mini shd outputs set in mono and the two inputs of the KEF? with mode set to LFE. Just for measurement?
Is the modeswitch active in both LFE and manual? whatabout gain and cutoff frequency? Will it play louder if I use both inputs on the KEF?

 

[HarmonicTHD]

can I ask some basic questions here?
Got Minidsp SHD connected to a tape in/out on my Luxman amp which is driving a set of Sonusfaber Guarneri Evo`s
My idea is that I find a good spot for the subwoofer using REW without using Dirac or any delays settings in the Minidsp. What confuses me is the different settings on the KEF.Shall I use 2 of the mini shd outputs set in mono and the two inputs of the KEF? with mode set to LFE. Just for measurement?
Is the modeswitch active in both LFE and manual? whatabout gain and cutoff frequency? Will it play louder if I use both inputs on the KEF?

To my best knowledge. You can setup the MiniDSP either way (LFE or 2channels). However for simplicity I would set it up for LFE (1channel) as there is no disadvantage and the advantage is that you only need one cable instead of two. (No it does not play louder with 2 channels).

As for cutoff frequency usually 80Hz is a very good start, but it depends how low your main speakers can go. If they can’t go low you might need to set it to ca 100Hz.

For measuring, you setup the system the same exact way as if you would play music through it.

Regarding the gain. Set it up so, before engaging the EQ, your SPL level of the sub matches the SPL level of your mains. Eg 80dB is usually an ok SPL level for measurements. Some go higher to match the quite load THX standard of ca 85dB. You can do that either with broadband pink noise.

 

[Jeschiotz]

To my best knowledge. You can setup the MiniDSP either way (LFE or 2channels). However for simplicity I would set it up for LFE (1channel) as there is no disadvantage and the advantage is that you only need one cable instead of two. (No it does not play louder with 2 channels).

As for cutoff frequency usually 80Hz is a very good start, but it depends how low your main speakers can go. If they can’t go low you might need to set it to ca 100Hz.

For measuring, you setup the system the same exact way as if you would play music through it.

Regarding the gain. Set it up so, before engaging the EQ, your SPL level of the sub matches the SPL level of your mains. Eg 80dB is usually an ok SPL level for measurements. Some go higher to match the quite load THX standard of ca 85dB. You can do that either with broadband pink noise.

...So,when using LFE input of the KEF, all the onboard adjustments(phase,eq,mode,crossover and volume) in KEF is disconnected?

 

[HarmonicTHD]

...So,when using LFE input of the KEF, all the onboard adjustments(phase,eq,mode,crossover and volume) in KEF is disconnected?

Yes. Except volume/ gain (see my post above). All other functions are controlled by your MiniDSP.

 

[KMO]

...So,when using LFE input of the KEF, all the onboard adjustments(phase,eq,mode,crossover and volume) in KEF is disconnected?

The MODE switch set to LFE disables the CROSSOVER (LPF) knob only. (And maybe the HPF?)

The PHASE (polarity), EQ and VOLUME controls continue to work in LFE mode.

The "LFE"-marked input (also L) works either way, independently of MODE. The sub simply auto-senses whether you have one or two leads connected. You're just supposed to use the L one if using only one wire.

The sub applies a 6dB gain increase when it senses you only have one wire connected, to achieve the same doubling of volume you would get by connecting both wires. (That's the "Smart Connect" feature.) This doesn't happen immediately, so can upset your second REW sweep measurement of a session. (The first one usually not working at all due to the auto wake-up delay). Third sweep should be fine.

Don't really see the point of that myself - just having a gain control with sufficient range would do the job, right? Not as if someone's going to be switching between one and two-wire connections on one calibrated setup, and wanting to maintain level.

Connecting both wires could avoid that start-up gain adjustment, and at least on much older KEF subs it made them better at staying awake. But one wire should normally be fine.

 

[Jeschiotz]

Yes. Except volume/ gain (see my post above). All other functions are controlled by your MiniDSP.

And what does the term smartConnect refer to?

 

[HarmonicTHD]

And what does the term smartConnect refer to?

Sorry. I don’t know that. I have (two) KEF KF92 so I am not familiar with the KC62 details. But the principles apply as well as described above. KMO and or the manual might know better.

 

[KMO]

As I said above, Smart Connect is that it auto-adjusts the gain depending on whether it senses one- or two-channel input.

The KF92 information sheet says:

"SmartConnect cleverly determines whether a mono or stereo input is being used and optimises the gain to ensure optimum performance"

I also said above that it seems a bit pointless, but on reflection, it probably is adjusting the internal gain structure to optimise the signal paths. It's quite possible that if they just had a single gain setup, if it could be set loud enough to reach max volume with one input, then that setting might be enough to overload/clip the DSP on two inputs, and they want to avoid that possibility. Or conversely, if it safely reached max level with max volume with 2 inputs, you might not be loud enough with 1 input - you'd maybe clip the ADC trying to get louder, or just not be able to reach the necessary voltage on your pre-outs.

When you have two signals, they would normally sum them. But when they detect a single input, they shut off the right one and then ramp up the gain on the left by a factor of two, taking up the headroom that would be used for summing, and it can achieve the same level, with the same input voltage on 1 signal.

 

[HarmonicTHD]

As I said above, Smart Connect is that it auto-adjusts the gain depending on whether it senses one- or two-channel input.

The KF92 information sheet says:

"SmartConnect cleverly determines whether a mono or stereo input is being used and optimises the gain to ensure optimum performance"

I also said above that it seems a bit pointless, but on reflection, it probably is adjusting the internal gain structure to optimise the signal paths. It's quite possible that if they just had a single gain setup, if it could be set loud enough to reach max volume with one input, then that setting might be enough to overload/clip the DSP on two inputs, and they want to avoid that possibility. Or conversely, if it safely reached max level with max volume with 2 inputs, you might not be loud enough with 1 input - you'd maybe clip the ADC trying to get louder, or just not be able to reach the necessary voltage on your pre-outs.

When you have two signals, they would normally sum them. But when they detect a single input, they shut off the right one and then ramp up the gain on the left by a factor of two, taking up the headroom that would be used for summing, and it can achieve the same level, with the same input voltage on 1 signal.

Thx. I didn’t even remember that my KF92s have smartConnect They both connect via LFE.

 

[Jeschiotz]

Ok,found i nice spot for the sub. Got it leveled and low pass set ok. But now the standby/signal led is out. It flashes when i turn it on and off with mains and when it goes active but then just fades to black. Woofer is still playing. Is that normal? Thought is should stay on all the time when on?

 

[kokoon]

Ok,found i nice spot for the sub. Got it leveled and low pass set ok. But now the standby/signal led is out. It flashes when i turn it on and off with mains and when it goes active but then just fades to black. Woofer is still playing. Is that normal? Thought is should stay on all the time when on?

That is normal. Light on when in standby, brief white when activating, then off when playing.

 

[KMO]

Thx. I didn’t even remember that my KF92s have smartConnect They both connect via LFE.

I just get reminded of it periodically when I'm faffing with REW. First trace graph might look a bit low, then I realise it's the SmartConnect still engaging. You can sometimes see it kick in during the trace - the low frequencies are 6dB lower than expected, but sloping up to the correct level at higher frequencies.

It must raise the gain over half a second or so, similar timescale to the sweep, so you get a bogus sloped frequency response measurement. Raising gain gradually would avoid a "pop".

 

[Vacceo]

Sorry. I don’t know that. I have (two) KEF KF92 so I am not familiar with the KC62 details. But the principles apply as well as described above. KMO and or the manual might know better.

I just want to take this chance to quote you since you recommended me the KC and KF subwoofers.

A couple weeks ago, I got the KC62 with a pair of LS50WII. The set works as a tv soundbar, radio player and CD player on a 10 square meter room.

The output I was skeptical about? I'm not skeptical anymore. The 62 is perfectly reasonable for a relatively small space and it provides more than enough TV and film low frequency output. That said, for a not much larger room, two 92's should be plenty considering room gain.

Thanks for the heads up! This set is fantastic and I can't wait to start upgrading my current seven channel setting!

 

[HarmonicTHD]

I just get reminded of it periodically when I'm faffing with REW. First trace graph might look a bit low, then I realise it's the SmartConnect still engaging. You can sometimes see it kick in during the trace - the low frequencies are 6dB lower than expected, but sloping up to the correct level at higher frequencies.

It must raise the gain over half a second or so, similar timescale to the sweep, so you get a bogus sloped frequency response measurement. Raising gain gradually would avoid a "pop".

Mhhh. Thx. Never had that in my REW sweeps. But good to know in case it comes up. I guess the sub was triggered to on by the test tones I had run prior to the actual sweep.

 

[fatnoah]

Tossing in my measurements of my existing R3 + KC62 that arrived on Monday. I took one measurement of the R3 alone and then a few with the R3 + KC62 at SPLs with a baseline at the upper end of what I normally listen at, with a couple moderate increases. All curves are using REW psychoacoustic smoothing. Signal chain is stereo line out from my DAC to the KC62, and line out from KC62 to poweramp. Volume is at 12 o'clock, LPF = 80 Hz, HPF = bypass, EQ = room.

Subjectively, it seems to play very nicely with the R3s and "completes" the sound to my ears. Just for kicks, I fired up the Techmaster P.E.B. Bass Computer 2000 CD and, at my normal listening volume, the KC62 was able to provide SPL at the "feel, not hear" level. It's definitely not going to shake the room like the 10" sub doing home theater duty in the same room, but I'm loving it for music.

Additional details for the curious: Room is and enclosed 19'x13' with tile floor, and totally untreated (the normal space is the extra bedroom occupied by the in-laws for the summer). Speakers and listening position are along the longer wall, not quite on center. Speakers are about 82" from each other (flanking my 80" desk) and 84" from the microphone (UMIK-1) position. Sub is tucked under my desk. I can definitely optimize the room and placement, but it sounds good enough to me that I probably won't bother until I move back to my normal space.

(knocking on wood) FWIW, I've had no standby issues with the sub. It comes out of standby at a far lower volume setting than my NAD C268, which required a significant boost to initially wake itself up, even at the most sensitive wake setting. In order to keep the volume of the KC62 in the 12 to 3 o'clock range, I have max the input trim on the C268, so it no longer wakes up by itself, but (unlike the kc62), it has a physical button, so it's not a big deal.

 

[Chrispy]

View attachment 219570

Tossing in my measurements of my existing R3 + KC62 that arrived on Monday. I took one measurement of the R3 alone and then a few with the R3 + KC62 at SPLs with a baseline at the upper end of what I normally listen at, with a couple moderate increases. All curves are using REW psychoacoustic smoothing. Signal chain is stereo line out from my DAC to the KC62, and line out from KC62 to poweramp. Volume is at 12 o'clock, LPF = 80 Hz, HPF = bypass, EQ = room.

Subjectively, it seems to play very nicely with the R3s and "completes" the sound to my ears. Just for kicks, I fired up the Techmaster P.E.B. Bass Computer 2000 CD and, at my normal listening volume, the KC62 was able to provide SPL at the "feel, not hear" level. It's definitely not going to shake the room like the 10" sub doing home theater duty in the same room, but I'm loving it for music.

Additional details for the curious: Room is and enclosed 19'x13' with tile floor, and totally untreated (the normal space is the extra bedroom occupied by the in-laws for the summer). Speakers and listening position are along the longer wall, not quite on center. Speakers are about 82" from each other (flanking my 80" desk) and 84" from the microphone (UMIK-1) position. Sub is tucked under my desk. I can definitely optimize the room and placement, but it sounds good enough to me that I probably won't bother until I move back to my normal space.

(knocking on wood) FWIW, I've had no standby issues with the sub. It comes out of standby at a far lower volume setting than my NAD C268, which required a significant boost to initially wake itself up, even at the most sensitive wake setting. In order to keep the volume of the KC62 in the 12 to 3 o'clock range, I have max the input trim on the C268, so it no longer wakes up by itself, but (unlike the kc62), it has a physical button, so it's not a big deal.

That's better than I thought but your graphic parameters make it look better than it is to an extent, altho only down 20dB at sub 20hz levels is somewhat impressive for a small limited sub like the kef.

 

[fatnoah]

That's better than I thought but your graphic parameters make it look better than it is to an extent...

Good point. I realized after I posted that the x-axis range makes it hard to see the details.

That said, it's definitely better than I expected, given the space I'm operating it in. It's performing well and I'm happy with the purchase, since size was an important factor.