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KEF LS50 Meta Review (Speaker)

Anyone seen measurements for LS50M comparing mid-bass output using KEF supplied foam plug vs using a handball (or similar) in port to approximate a true sealed cabinet output.
CJH
no but, enjoy this:
 
Heads up - the LS50 Meta are on sale for $1000 USD right now. Sale started yesterday. Looks like many sellers are honoring it - Amazon, Best Buy, Crutchfield, even my local AV shop had them for sale (without asking for price match). Looks like last year the sale started later in Nov and lasted through till the beginning of Jan, according to camelcamelcamel (which tracks prices on Amazon):

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I believe they were on sale last year for $1200. If you compare Q series & LS50 builds I always suspected there was flexibility in KEF's pricing. Of course, KEF's just announced the Concerto Meta at $1300, it's comparable to an R3 at $2200 with a revoicing so they're similar but different. This is all to keep market share. The Brits in general have been aggressively revamping models (mostly for the better with commensurate price increases) both in electronics & speakers, more power to them. Cheers!
 
Yea, definitely worth considering the Concerto Meta. I think their benefit is they can play louder with less distortion than the LS50 Meta. Unfortunately the Concerto Meta are too tall for my (literal) bookshelf.
 
Yea, definitely worth considering the Concerto Meta. I think their benefit is they can play louder with less distortion than the LS50 Meta. Unfortunately the Concerto Meta are too tall for my (literal) bookshelf.
agreed , for those that want more of a "full sound" and are willing to give up a smidge of transparency to get it , the concerto seems like a viable option ... i would think it might appeal to more folks than the ls50 meta in general....as a matter of fact i haven't heard anyone say yet that the ls50 meta is more transparent ... with a dedicated mid the concerto may be just as transparent with less forward presentation...i would guess the concerto would appeal to those that might also be considering the ascend sierra 1 v2....if i was going to (arguably) upgrade from my Dennis Murphy modded emotiva b1's , both the concerto's and the sierra's would be on the short list( along with Dennis's ceramic mini)....thank goodness for my wallet i'm pretty happy now...as far as the ls50 meta's , i would think "refinement" might be the only upgrade from b1's, so they really aren't on my short list of possible "upgrades"....
 
I just got a WiiM Ultra and now have the capability to high-pass filter my LS50 Metas with the subwoofer integration. Do you guys think 70Hz is a good crossover point, or do you suggest something else?

-Ed
 
I just got a WiiM Ultra and now have the capability to high-pass filter my LS50 Metas with the subwoofer integration. Do you guys think 70Hz is a good crossover point, or do you suggest something else?

-Ed
The manual for the Metas has it at 80Hz and it's where I have it.
 
I just got a WiiM Ultra and now have the capability to high-pass filter my LS50 Metas with the subwoofer integration. Do you guys think 70Hz is a good crossover point, or do you suggest something else?

-Ed
Looking at Appendix 2 - Ports here https://assets.kef.com/pdf_doc/LS50Meta/KEF-LS50Meta-LS50WirelessII-WhitePaper.pdf and the impedance measurement here https://www.stereophile.com/content/kef-ls50-meta-loudspeaker-measurements it seems the port is tuned to ~56hz. The enclosure will be acoustically open below that, i.e. the air mass will not dampen the excursion of the speaker cone. You need to take that into account, especially if you run DSP that might increase the level below 56hz. I would suggest a higher crossover frequency like 110hz if you can get away with it.
 
Looking at Appendix 2 - Ports here https://assets.kef.com/pdf_doc/LS50Meta/KEF-LS50Meta-LS50WirelessII-WhitePaper.pdf and the impedance measurement here https://www.stereophile.com/content/kef-ls50-meta-loudspeaker-measurements it seems the port is tuned to ~56hz. The enclosure will be acoustically open below that, i.e. the air mass will not dampen the excursion of the speaker cone. You need to take that into account, especially if you run DSP that might increase the level below 56hz. I would suggest a higher crossover frequency like 110hz if you can get away with it.
Doesn’t 110hz result in some directional sound being produced by the subwoofer?

-Ed
 
The WiiM Ultra makes adjusting the crossover point from the comfort of your MLP so easy, there's really no reason to stick to crossover frequency advice from other people or KEF's manuals.

Just have a seat, put on some good tunes, play around with the crossover slider in the WiiM Home App, and see what works best.
 
Doesn’t 110hz result in some directional sound being produced by the subwoofer?
The claim you can not hear direction below 80hz is not correct. It depends on crossover frequency, the slope and the location of the subwoofer. I could clearly hear subs crossed at 80hz. Just test it. If the subs are close to the satellites you can use higher xo freq. Given the rather high bass reflex tuning frequency of the LS50, I would try to get away from this frequency, preferably by an octave. You could also try plugging the port and making the LS50 a closed box, however this will increase excursion as well and has to be compensated for. As you see the driver itself already falls off at ~100hz, so you again end up with a crossover frequency around 100hz :p

I used MiniDSP/REW to measure the mains versus the subwoofer using 10Hz increments and in my case, settled on 110Hz after measuring and listening. I have the KEF LS50 Meta.
I love it when theory and experimentation arrive at the same results :cool:
 
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My approach is something like this... the goal is to find the lowest crossover that is practical, keeping in mind the LS50 Meta's main weakness as a speaker is distortion in low frequencies at higher output.

With desired EQ applied, first set a relatively high crossover, say 150, and begin listening at the highest volume that you think you will listen (with material that has as much low end content as you listen to). Maintaining that volume level, incrementally lower the crossover (eg in 10hz jumps) until you begin to hear distortion or if you notice the cone is unloading. Once that kicks in, the process is done and you can set your crossover 10hz above that. eg if you begin to hear distortion at 90hz, set the crossover to 100. Adjust as needed over time (as some tracks are recorded louder than others, have more low end content, etc).

Another consideration is to use two crossovers points (not simultaneously..). One that is relatively low, like 60hz - this is for lower volume listening. The other is a higher crossover point that you use when you want to listen louder.
 
My LS50 Metas are about 8 feet apart, about 10 feet away from listening position, with my SVS SB-3000 placed precisely midships between them, same distance away.

I've gone ahead and started experimenting with much higher crossover point, 110Hz. Indeed, I am so far not noticing any strange imaging effects, but I am definitely noticing better tonality (likely a manifestation of having less distortion). And one thing is for sure, I can crank these things WAY WAY higher without the B100 monoblocs kicking into safety mode.

-Ed
 
I just got a WiiM Ultra and now have the capability to high-pass filter my LS50 Metas with the subwoofer integration. Do you guys think 70Hz is a good crossover point, or do you suggest something else?

-Ed
I crossover mine at 120hz or higer if you position it well and if the sub is flat to 150 like svs sb 1000 pro. That is because ls50 m is bad i bass range.
 
The claim you can not hear direction below 80hz is not correct. It depends on crossover frequency, the slope and the location of the subwoofer. I could clearly hear subs crossed at 80hz. Just test it. If the subs are close to the satellites you can use higher xo freq. Given the rather high bass reflex tuning frequency of the LS50, I would try to get away from this frequency, preferably by an octave. You could also try plugging the port and making the LS50 a closed box, however this will increase excursion as well and has to be compensated for. As you see the driver itself already falls off at ~100hz, so you again end up with a crossover frequency around 100hz :p


I love it when theory and experimentation arrive at the same results :cool:

It's hard to make blanket statements like this because there are many studies on low frequency localization and when tested blind most people can't detect subs below about 120-140Hz, I summarized some of these studies here: https://www.avsforum.com/threads/subwoofer-localization-studies.3058756/

I have done many tests with the LS50's and higher crossover points and generally stick around 100Hz but your sub level relative to your mains has a huge impact on whether you'll localize your subs or not, if you don't have a huge sub boost it is much harder to localize. What people don't ever talk about is most high passes are 2nd order so even if you're crossing at 120Hz, the actual acoustic crossover is going to be lower. Right now I have my LS50 crossed at 100Hz 2nd order and my sub 90Hz 4th order and my in room measured response shows them crossed right around 80Hz. A 100Hz 2nd order high pass is less attenuation than an 80Hz 4th order high pass so no need to be afraid of slightly higher crossovers, they let the LS50 play louder with less distortion.
 
It is hugely room dependent. One can easily use something like Dirac to observe measured behavior when moving the sub around and trying optimal xover. Doesn't take long either.

Mine is at 70Hz. But not claiming that's optimal for everybody.
 
It is hugely room dependent. One can easily use something like Dirac to observe measured behavior when moving the sub around and trying optimal xover. Doesn't take long either.

Mine is at 70Hz. But not claiming that's optimal for everybody.

In room response is only half the equation though, you can see the distortion rises rapidly below 100Hz so that is a great reason to not cross below 100Hz, if you don't listen very loud this is less important of course
 
In room response is only half the equation though, you can see the distortion rises rapidly below 100Hz so that is a great reason to not cross below 100Hz, if you don't listen very loud this is less important of course
yeah, I'm seeing almost every mini monitor that gets klipple'd has some kind of distortion issue at higher spl, even the very well built types .. The ceramic mini and sierra 1 v2s , both great designs with good pir have mid / sub bass distortion issues at high volume..i think it has to be simple physics...
 
yeah, I'm seeing almost every mini monitor that gets klipple'd has some kind of distortion issue at higher spl, even the very well built types .. The ceramic mini and sierra 1 v2s , both great designs with good pir have mid / sub bass distortion issues at high volume..i think it has to be simple physics...
Radiant Acoustics Clarity 6.2:

Almost identical size to the Sierra-1 V2, but ridiculously low bass distortion.

It'll cost you though..
 
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