Good. I currently use the SEOS-12 crossed to a Deltalite 2515II. I've been experimenting with dome tweeters instead of CDs with the SEOS-12. Looks good so far.
There's a perfectly valid reason to sell a loudspeaker with a rise in the on-axis response:
When combined with a waveguide, you get a power response which doesn't have that rise.
This is Waveguides 101; I'm certain Kef was aware of this effect, and it's 'designed in.'
Also, there are lots of good reasons to listen to a speaker off-axis, just read the Geddes white paper on how to set up his speakers, it explains it.
Full disclosure:
I own both Kef and Geddes speakers. I listen to both off-axis.
Don't have access to pics right now. The crossover is about 1.3 kHz. Acoustical target LR4. But the electrical slopes are asymmetrical to get the correct rolloff and phase overlap. The Deltalite is really a great driver, but 1.3 kHz is stretching it. A 12" driver is a better match for the SEOS-12. But I'm getting a SEOS-18 from the next group buy, and that should allow a lower crossover with the 2515.
I see you have a lot of cone area, which is always good. Should be a smooth, dynamic system.
I see you have a lot of cone area, which is always good. Should be a smooth, dynamic system.
Crossover points are 50, 100, 200, 450 and 1.4k. The idea behind the driver count is to have total flexibility when it comes to flattening the in room frequency response without putting too much strain on any one woofer. Distortion is obviously very low also. I managed to get a hold of some rare 4" hds exclusive mids.
http://pas-bg.com/Peerless/Peerless Data Sheet - ID 830881.htm
The 5.25" midbass' in the top units will be replaced with these for obvious reasons. The distortion above 400hz with these 4" units is also pretty amazing.
http://vmaudio.cz/clanky_pokracovani/mereni_vysledky/4HDSE/GCS0004.png
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I'm also going to use them between 600 and 2khz. Their efficiency sucks, but I'm all active so it doesn't really matter.
ra7, as I said, I've heard them, albeit briefly and in a specific context. In practice the lack of absolute fr flatness is not 'an obvious flaw' and I didn't find them particularly bright compared to other high quality speakers. I've worked in audio retail, I've been building speakers for over thirty years and heard a lot of high quality speakers. I have played and, mostly, sung in local rock and folk bands for many years. This doesn't mean my opinion is worth more than other people's, but I do have quite a bit of perspective and quite a bit of experience with speakers and speaker designs. I've heard all kind of systems with different fr, directivity, bass extension, etc., etc. and I think it's a good speaker. If you don't, that's fine, but bearing in mind it's price and size it sounds very good. If what you want is a good sounding small speaker, which will inevitably be limited in terms of loudness and bass extension compared to larger designs, it's one of the best I've heard recently. 'Flatter' is a useful and important design goal, but it depends on how flat is considered necessary and possible in the context of the rest of the design. How flat is flat enough? 1dB flatter? 2dB? My quick audition suggested that it is flat enough- but I'd certainly want to listen longer on a greater range of music at home with my own system if I was looking to buy a pair or offer a cast-iron recommendation to someone else. The Q100 driver does not appear to be the same as the one in the LS 50, but you may well be able to design a better speaker- or one that is more to your taste- with the Q100 drivers. 'Don't praise it like it's the next best thing since sliced bread'. I'm not. I'm praising what seems to me to be a good speaker system- but even if I was, that would be my opinion based on my (limited) experience. You are welcome to disagree, but don't tell me what I'm hearing or what to think about it! 😉
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If I'm not mistaken, the OP and RA7 haven't *heard* the Kef.
Their opinion is based on a set of measurements that have been published.
You and I have seen the measurements *and* we've heard the speaker.
Yep. I suppose I'm just a bit surprised that what is actually a pretty good fr is causing such consternation. Yes it's small, yes it's a commercial, budget constrained product, yes it isn't perfect. These things are obvious surely? Which competing, conventionally distributed product is definitively better designed and better sounding? I'm not saying there isn't one, but I haven't heard it. Oh well. Just trying to inject a bit of perspective and context, but I'm the last person to deny anyone their opinion, even if it is just based on a graph.
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And John Atkinson, who has probably tested and listened to more speakers than anyone in the history of audio, gave them a "class A" rating. The average speaker in "class A" costs about $20,000. To have one for $1,500 is pretty cool if you ask me. There are some on this forum who believe that they are the ultimate judge of sound quality with very little to back it up. In my opinion, that title, without a doubt, belongs to John Atkinson.
I doubt John would say that of himself! I think he is quite a rational guy and certainly one of the most experienced and technically literate speaker reviewers. I see a lot of negative comment on Stereophile generally and John Atkinson in particular, but I think his reviews of speakers and his measurements for other Stereophile reviewers are very useful. OT I know, but I notice you are not using the BG planars in your speakers any more Remlab. Problems or just preference?
I was going through the Stereophile standmount tests and after two pages, only one test (on a PSB) did NOT have a treble lift.
The small speaker norm is a midbass lift of about 5dB and a similar high treble lift to balance - boom and tizz
The small speaker norm is a midbass lift of about 5dB and a similar high treble lift to balance - boom and tizz
Interesting. Is that the nearfield response or in-room? The LS 50 would be flatter than average in that case. I expect designers have found buyers like that balance- or at least it sells better! I would still maintain that building for the market is just the realities of informed commercial product design rather than ignorance and cynicism, but hey, if people have an issue with how commercial speakers are 'voiced' fair enough. As experienced DIYers we generally have the knowledge, tools- and good taste? 😉 - to design flat fr in to our speakers and to design specifically for our listening spaces. It does come at the cost of being obsessive maniacs of course, which I'm as guilty of as anyone on here- in fact I'm off to the workshop now! The reviewers and designers I've met over the years are just the same really, it's just that they do it for a living which offers a lot of opportunities but comes with it's own constraints.
John would never verbally admit to that, because of his modesty, but he's quite aware of his accomplishments. If anyone out there has achieved half, or even a quarter of what he's achieved, I would love to know who they are. Names?
The BG's were purchased for dipole use. My room, as you can see, is not very dipole friendly. When my oldest son moves out, his room will work perfectly for a pure dipole system, using the BG neo 10's and 3's with two "Pass" style slot loaded 15's per side. I still love them.
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There is a review of the Atohm GT 1 in the April 2013 HiFi World. It is almost ruler flat form 70 Hz to 17 kHz. The review notes "no subsonic bass" and "strong treble" (minimum treble setting). To me this looks like the effect of the unusual lack of mid bass boost
Yep, great drivers Remlab. I've just replaced a pair of Audax HM100Z0s in my friends 4-way active system with Neo 8s. Much better, good though the Audax drivers are.
Certainly possible David, although there's always the danger of mistaking correlation for causation!
Certainly possible David, although there's always the danger of mistaking correlation for causation!
In the same April 2013 HiFi World, the Cabasse Pacific is well received. It's another off axis frequency response hiding the 5db treble lift (which is in the text).
I am really thinking some of these reviewers have hearing loss
I am really thinking some of these reviewers have hearing loss
High respect for Sean Olive aside, this has always been my caveat with the methollogy he and others use; it compares devices against each other for preference instead of against a source for similarity.
I did some research and tried to understand how this approach could sound right. You are saying that a rise in the on-axis FR is ok as long as the power response doesn't have that rise. Now, I cannot find a measurement of Abbeys or other Gedlee speakers that have that characteristic. (I didn't find that measurement on his website, and had to look into forums and such. The tool on his website doesn't appear to work.)
It also doesn't explain why the KEF folks didn't design their Reference line this way. They basically have the same configuration as the LS50.
I have waveguided speakers too, SEOS-12. And I have never found an on-axis rise to sound anything other than bright, no matter what the power response.
It might be time to start asking some questions, and not follow the 'experts' blindly.
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