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KEF LS50 Meta Review (Speaker)

alont

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Would love to hear from @amirm and @hardisj about what could cause this difference and possible ramifications as a result (more troublesome SBIR from the LS50 meta seems like one). I was debating between the R3 and LS50 meta for a while now, and just ordered the LS50 metas. Thinking it might have been a mistake now...
 
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alont

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Probably best explained by the port output as shown in the ASR review of the LS50M

View attachment 176481
Yeah the port seems like an obvious possible explanation, however looking at the measurements done by audioexpress (which were done with the port plugged), I still see the same extended rear radiation:
20210630203429_Figure3-KEFLS50Meta-Measurements (1).png
 

muad

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They both have the same width (7.9"), but maybe the curved ls50 results in a higher baffle step?
 

Ataraxia

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Would love to hear from @amirm and @hardisj about what could cause this difference and possible ramifications as a result (more troublesome SBIR from the LS50 meta seems like one). I was debating between the R3 and LS50 meta for a while now, and just ordered the LS50 metas. Thinking it might have been a mistake now...

What would you expect to happen during listening because of this? Is that really a fatal flaw if true of the Metas in your opinion?
 

abdo123

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Something I just noticed in the measurements - seems like compared to the R3, the LS50 Meta project a lot of energy backwards up to around 1100 hz - why is this?

Here's the LS50 Meta's horizontal contour plot, as measured by Amir:
index.php


Here's the R3's normalized horizontal contour plot, taken from Erin's review of the R3:
Kef%20R3%20Horizontal%20Contour%20Plot%20%28normalized%29.png


Maybe the R3 has additional absorption material inside the enclosure? Could that explain the difference?

Wouldn't this mean that the LS50 meta is more prone to to SBIR at higher frequencies?
The R3 has a bigger baffle which makes it forward firing earlier. Everything else can be explained by the speakers being different.
 

Ataraxia

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Nope, I ended up keeping my order of the LS50. I don't think this should pose too much of a problem.
You'll be very happy. I have both R3's and Metas and both are excellent speakers.
 

maty

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LS 50 Meta open baffle like sound

[ Just wanted to share this because this thread popped back in to my mind yesterday.
I had the meta now for some days and really liked them compared to the old LS50 which were kind harsh I felt in the upper ranges.

Regarding the crossover: these are definately different. Also spaced out on two plastic boards. this is the lower board. ]

KEF LS50 Meta crossover LF.png
 

KMO

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KEF white paper talks about the crossover difference - your picture must be of the LF board.

The topology of the crossover of the LS50 Meta is shown in figure 24. The smoother response of the new tweeter has resulted in fewer components in the HF filter and the remaining series capacitor (C1) is of higher quality.

The LF filter is similar to that in the original LS50, but includes an extra low-Q parallel resonance branch (C3-R3-L4) to compensate for the higher sensitivity in the
driver’s upper midrange due to its lower inductance.

The inductor L4 is the only one in the crossover to have a core. It is vital that only the resistor R3 controls the Q of the branch. To that end, the resistance of L4 (which is subject to change as it heats up when passing current) is kept as low as possible. As the core is a possible source of harmonic distortion if it nears saturation, measurements were taken to relate the current passing through L4 with that passing through L2. Figure 25 shows that it will be seen that the current passing through L4 is much lower and the chances of its core saturating are virtually nil, a fact borne out by the THD measurements of figure 23.

To minimise any coupling between inductors, the three in the LF filter are arranged orthogonally and the HF filter is on a separate board, placed well away from the LF filter.

1641387981704.png
 

Ataraxia

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Which one do you like best and why?

I'm not sure yet but I'll mention some things I've learned.

From reading others' experiences and now quite a bit of time listening to both I feel it depends which ones you're psycho-acoustically used to.

If you have Metas and try to switch to R3's you might miss the better point source presentation and ability to disappear.

If you have R3's and switch to Metas you might miss the scale they present above the Metas. R3's present practically like floor standers with a more room filling sound. They can work better for you in a larger room at greater distance.

It also seems to me that first listening distance, then room size, are the differentiators, not the speakers.

I've been considering downsizing and keeping one set but since they each have their own characteristics I still can't decide. If I knew I'd be in a small apartment or room indefinitely I'd keep the Metas. Due to the point source presentation it seems they are easier to place for optimal imaging and disappearance. If I was in a large room I can still use the Metas but I would still want to be less than 7' triangle sweet spot.

I feel since the Metas can be used in any size room, even deskfield, and if placed properly will almost completely disappear leaving excellent imaging and soundstage, I'd lean Metas for versatility. On the other hand, R3's placed well in a medium room 7-9' triangle could go solo no sub, where you might, but don't need, to have a sub with the Metas.

Shower thought: *Metas can be placed between listening position and TV screen without distracting reflection, Black/white gloss R3's cannot. That limits my positioning of the R3's in my tiny living room.

I'm glad I could make your decision for you. :) /S
 
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Descartes

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I'm not sure yet but I'll mention some things I've learned.

From reading others' experiences and now quite a bit of time listening to both I feel it depends which ones you're psycho-acoustically used to.

If you have Metas and try to switch to R3's you might miss the better point source presentation and ability to disappear.

If you have R3's and switch to Metas you might miss the scale they present above the Metas. R3's present practically like floor standers with a more room filling sound. They can work better for you in a larger room at greater distance…..Shower thought: *Metas can be placed between listening position and TV screen without distracting reflection, Black/white gloss R3's cannot. That limits my positioning of the R3's in my tiny living room.

I'm glad I could make your decision for you. :) /S
Thanks, may the new R3 meta will have non glossy finish!
 

Ataraxia

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Thanks, may the new R3 meta will have non glossy finish!
Walnut is still attractive IMO for those inclined to buy before potential new models.

I hope we hear soon what they will be.
 

Ataraxia

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Is the walnut finish glossy or matte?
I've never seen it personally but it sure looks matte/flat wood finish to me. It might slightly reflect but probably not enough to be distracting.

I had my black gloss R3's pulled from the wall but it was immediately distracting with the TV screen and all the motion being reflected off both R3's.

So I had to push them back to where you see in the pictures in this thread above
 
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