Kef LS50

[ErinH]

Just finished up testing on the Kef LS50 driver. I hope to run the R-series concentric through the Klippel sometime this weekend. Maybe. I also realized that my calculation for the Kef Q100 I tested last year for surface area was wrong, and I thought I had already corrected it. So, I wound up taking down my data and will re-test large signal parameters for that later as well.

Results on my site here:

http://medleysmusings.com/kef-ls50-drive-unit/

[ErinH]

Kef LS50

The distortion sweeps look good, with about 50dB separation (~0.30% THD) in the nominal passband for both the woofer and the tweeter. That's superb.

The woofer's THD hits about 3% at 100hz. The tweeter's 3% THD is at about 1.5khz.

woofer @ 96dB/1m equivalent:




tweeter @ 96dB/1m equivalent:




Overall FR looks good as well, factoring in these drivers are not flush mounted and this does change the response.

[augerpro]

Re: Kef LS50

What was the Fs on the Q100 tweeter?

[ErinH]

Re: Kef LS50

I don't know if I ever tested that, TBH. I'm going to re-test the Q100 and test the R-series concentric soon, so I'll have all that data up on my site soon.

[Pallas]

Re: Kef LS50

Looks improved over the Q100 driver.

You know what might be a nice solution for you, assuming you have three of the LS50 drivers? A riff on the old Allison speakers: put an 8" or larger woofer (maybe the SB's would work well, since you have them; they'd be great as test mules) on the floor, the LS50 concentric maybe centered 25-28" off the ground and angled back a bit. Two in the corners and one in the middle. Active cross between concentrics and woofers. Set the mid-woofer crossover so that floor bounce is in the stop band of the mid.

That uses boundaries in your favor to give you more output from the floor mounted woofer as well as eliminate floor bounce, and is possible because the LS50 driver will play cleanly an octave lower than the dedicated mid Uni-Q will.

[ErinH]

Re: Kef LS50

It's not out of the realm.

I'm actually considering AE TD10 woofers (either the s or h version). Thinking that flanking this concentric with two of those per cabinet would be pretty sick.

[johnnyrichards]

Re: Kef LS50

That looks like a very nice combo for use as the T/M in a large 3-way.

[Pallas]

Re: Kef LS50

It's not out of the realm.

I'm actually considering AE TD10 woofers (either the s or h version). Thinking that flanking this concentric with two of those per cabinet would be pretty sick.

If you're thinking about doing it R900 style I still think the R-Series driver would be a better choice than this one, especially given that you have both. This one offers the flexibility of "solving" floor bounce with just a woofer and the concentric, and it's clearly better for use in an SAM1-style speaker where the woofer lowpass is limited by the crossover options available on standard subwoofer plate amps. But in any more standard configuration I don't see any advantages for this one over that one.

[Jeff B.]

Re: Kef LS50

It's not out of the realm.

I'm actually considering AE TD10 woofers (either the s or h version). Thinking that flanking this concentric with two of those per cabinet would be pretty sick.

Where can someone purchase the Kef driver at, Erin?

[winslow]

Re: Kef LS50

You can't without a serial number for a replacement or buy the loaded cabinet.

[ErinH]

Re: Kef LS50

Winslow is right. You have to have a serial number for replacement part purchase.

I wish that weren't the case.

[clydethecat]

Re: Kef LS50

While you've got the LS50 torn apart, any chance of tracing a schematic of the crossover?

[6thplanet]

Re: Kef LS50

If you can't buy it and a set new is in the $1K realm, whats the point?

[Pallas]

Re: Kef LS50

While you've got the LS50 torn apart, any chance of tracing a schematic of the crossover?

See first post in this German thread, under "Originale Schaltungstopologie." I think I've seen a schmatic with values somewhere, but can't remember where.

If you can't buy it and a set new is in the $1K realm, whats the point?

Aren't you interested in knowing what goes into elite commercial speakers?

Also, some people will pay $500 or more for a drive unit (Accuton cone, Raal ribbon, TAD compresison driver, etc.), so a $1000 price tag for a pair of really good concentric drivers to use in whatever project isn't necessarily a barrier. That color, however...

[craigk]

Re: Kef LS50

Aren't you interested in knowing what goes into elite commercial speakers?

while I get what you are saying, a $ 1500.00 dollar speaker is not in the "elite" class of anything. it is simply a nice sounding speaker.