Would the KEF LS50 Speakers Be a Let Down?

mep · Jun 9, 2013

After having owned the Def Tech BP7000SC speakers for a number of years, I wonder if I am crazy to even contemplate buying the KEF LS50 speakers. The Def Tech speakers are full range speakers with a built in 14" sub driven by an 1800 watt amp. The Def Tech speakers are rated for 1000 watts of input power. Using them with my Krell KSA-250, I have never found a point on the volume control where either the speakers or amp cry "Uncle." Your ears will give out first.

I am intrigued by the little KEF LS50 speakers. There has been a ton of engineering that went into them. The coaxial driver is very high-tech and so is the cabinet. Lots of work went into designing the front baffle, and the interior of the cabinet with its bracing and constrained layer dampening. All of the reviews have been glowing including the show reports from Newport 2013. I have a pair of the Def Tech subs which have the same 14" woofer and 1800 watt amps that are in the BP7000SC speakers so bass shouldn't be an issue (other than two 14" drivers and two 1800 watt amps would now be out of the picture). My concern would be getting satisfactory SPLs out of these speakers in my 15' x 23' x 9' room (not to mention the L-shape portion which adds another 4' in width at the listening end of the room). I would hate to blow the damn things up.

I do think that based on their shape they should image like crazy, be very coherent sounding with very little cabinet distortion. I think that large floor standing speakers that are heavy have to store and release much more energy which would smear the sound compared to a pair of LS50 speakers. If that little JOB amp that is currently the rave sounds as good as the initial reports, it may be just the ticket for the LS50s. I'm afraid that my KSA-250 might be too much amp for them in terms of available power.

So, I am looking for opinions on whether this would be a stupid move or possibly a good move. Something about them intrigues me. I do feel that they may go up in value over time if they are truly limited in their production.

JackD201 · Jun 9, 2013

I haven't heard them so I'm just going by their published numbers. Looks like you'd need to be crossing your subs over pretty high, above 80Hz maybe closer to 100Hz. How linear are your subs in your room from there on down? As for the KSAs, I wouldn't sweat it. You'd have to be irresponsible to blow the speakers out.

mep · Jun 9, 2013

Jack-I think my subs would be fine although I have never crossed them over that high before because I had no need to do that. My main concerns are I would be going from having 18 drivers down to 4 drivers (not including the 6 in the pair of subs). I can't imagine they would pressurize the room in the same way. As far as being irresponsible, I have never blown a driver before, but there is always the first time.

I'm just afraid that I might push them too hard in an attempt to fill the room.

Steve Williams · Jun 9, 2013

Mark

Keep your speakers and see if you can buy the LS50 for the $1200 show special. I heard them and IMO they were the show stopper. I could not believe the sound.

I'd keep both systems

mep · Jun 9, 2013

Steve-Any leads on who would sell them for the show special??

FrantzM · Jun 9, 2013

JackD201 said:
I haven't heard them so I'm just going by their published numbers. Looks like you'd need to be crossing your subs over pretty high, above 80Hz maybe closer to 100Hz. How linear are your subs in your room from there on down? As for the KSAs, I wouldn't sweat it. You'd have to be irresponsible to blow the speakers out.

I am with Jack here. I am actually considering these speakers as an interim. Small enough for my present Living Room and from all reports excellent sounding... I will use subs of course. While they could well be better sounding than your present speakers .. They may not provide the full range sound you have grown accustomed to ... I haven't heard them so I am on a thin ice here ... in my experience mini monitor plus subs have a sound of their own .. Always different and for me less satisfying than that of true full ranges (which in my world view should also be used with subs)

joeinid · Jun 9, 2013

mep said:
Steve-Any leads on who would sell them for the show special??

I'd buy a pair too.

JackD201 · Jun 9, 2013

You know the cliche my friend, only way to know for sure is to try. I definitely wouldn't mind buying a pair myself if it really is heir to the LS3/5a which I love. I've been looking at these though.

http://www.youtube.com/watch?v=WYJjs_x-oVU

joeinid · Jun 9, 2013

Those FOSTEX?GX102MA seem awesome. Are they available in the USA?

RBFC · Jun 9, 2013

Mark,

Perhaps the better question is how they would handle the lower midrange in regards to power compression. Above the crossover frequency, many smaller speakers seem to become anemic in this range when played loud. Of course, I didn't hear them, so this is "outloud wondering"!

Lee

flez007 · Jun 9, 2013

Mark, I moved from a pair of SF Guarneri to WLMs and then the Avalon Ascents, I really enjoyed my time with the Guarneris and still miss some things that were great thru them...now...one thing I do not miss is the saturation I got when played loud in my room/system. The SPL delivered by the Avalons is adictive, not to mention the extra frequency response gap delivered as a whole from a single cabinet.

DaveyF · Jun 9, 2013

flez007 said:
Mark, I moved from a pair of SF Guarneri to WLMs and then the Avalon Ascents, I really enjoyed my time with the Guarneris and still miss some things that were great thru them...now...one thing I do not miss is the saturation I got when played loud in my room/system. The SPL delivered by the Avalons is adictive, not to mention the extra frequency response gap delivered as a whole from a single cabinet.

Fernando, you heard my GH's in my small room. I think in a room of this size, SPL's are not that much of a factor for a smaller speaker in a smaller room. Perhaps it's the old advice...small room/small speaker, Big room/Big speaker.

Although, I do believe that a small speaker will always benefit from a sub regardless of room size. But as you state, a single large cabinet can make everything more 'complete' sounding. One just has to be more careful matching a sub to a stand mount sat. BTW, are we really listening that loud? I know that I do NOT listen at SPL's that would likely damage my hearing, which I suspect that a lot of a'philes make the mistake of doing.
If you really have to turn it way up, I suspect something is wrong with the system. IMHO.

mep · Jun 9, 2013

Guys-I appreciate the inputs and there are lots of good thoughts here. I just don't want a big let down. Fernando brought up a good point about compression which is certainly not an issue now and it's one of the things I really like about my speakers. You simply can't push them too hard-or at least I can't. Frantz brought up a good point as well with regards to floor standing speaker sound compared to stand mount speakers. The LS50s should sound very clean and open unless/until you hear the point where they start into thermal compression. I'm just afraid that I will push them too hard, but I guess you don't know until you hear them. According to JA, they measure great and they sound great and that is why he gave them a Class "A" low frequency limited rating. To be rated in Class "A" for a pair of speakers costing $1500 is pretty special. There is just something about these speakers that has me excited by thinking they really could be something very special. KEF must have had their room *right* at Newport because I don't remember so many positive comments coming from any other show.

Steve Williams · Jun 9, 2013

Mark

Usually a show special is honored for 30 days after the show. I'd call Kef direct. I'd also contact Amir here who is a Kef dealer.

It was a Kef room. No dealer involved.

JackD201 · Jun 9, 2013

joeinid said:
Those FOSTEX?GX102MA seem awesome. Are they available in the USA?

I have no idea. Probably not. I'm this close to pulling the trigger on a pair from a Japanese online shop. Cost is around $1,500 also. I'm particularly enamored with the MG130HR full range drivers used. These were limited, hand made runs for the DIY community and their prices are beginning to soar now that production has ended. Up to $700 bucks per driver now on e-bay, madisound has only 1 pair left (they only had an allocation of 8pcs I was told). These speakers have four of them as well as the magnesium tweeters. It's a downright steal.

Shaffer · Jun 9, 2013

mep said:
My concern would be getting satisfactory SPLs out of these speakers in my 15' x 23' x 9' room (not to mention the L-shape portion which adds another 4' in width at the listening end of the room). I would hate to blow the damn things up.

I was in a situation similar to yours, kinda, not too long ago. Big speakers, little amp and a need for a sound that kicked ass. It did just that between 11PM -5AM, but only then. It was the only time the noise level was low enough to allow for a sensation of impact.

mep · Jun 10, 2013

Shaffer said:
I was in a situation similar to yours, kinda, not too long ago. Big speakers, little amp and a need for a sound that kicked ass. It did just that between 11PM -5AM, but only then. It was the only time the noise level was low enough to allow for a sensation of impact.

I don't have a little amp and I don't have a problem with noise levels in my room. It is a dedicated space that is acoustically isolated from the main part of my house.

Shaffer · Jun 10, 2013

mep said:
I don't have a little amp and I don't have a problem with noise levels in my room. It is a dedicated space that is acoustically isolated from the main part of my house.

I understand that you have a very powerful amplifier, but the speakers you're considering cannot transform that juice into real impact; hence, the lay comparison. Good luck with whatever you choose.

mep · Jun 10, 2013

Shaffer said:
I understand that you have a very powerful amplifier, but the speakers you're considering cannot transform that juice into real impact; hence, the lay comparison. Good luck with whatever you choose.

Felix-I got you now. You had big speakers and a little amp, and I will have a big amp and little speakers. And that is exactly what I'm worried about with regards to how well the LS50s would fill my room with sound.

Randall Smith · Jun 10, 2013

http://www.soundstagehifi.com/index.php/equipment-reviews/557-kef-ls50-loudspeakers

Doug loved them. I have considered them as well.

Would the KEF LS50 Speakers Be a Let Down?

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