KEF Reference 5 loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Analog Source: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge.
Digital Sources: Aurender N10 music server; Ayre Acoustics C-5xeMP universal player; Ayre Acoustics QX-5 Twenty & QB-9DSD, PS Audio PerfectWave DirectStream D/A converters; AudioQuest JitterBug, UpTone Audio ReGen USB cleaner-uppers; Mac mini running Vinyl Studio, Pure Music 3, Audirvana 1.5, Roon 1.3; Ayre Acoustics QA-9 USB A/D converter.
Phono Preamplifier: Channel D Seta L.
Preamplifier: Ayre Acoustics KX-5 Twenty.
Power Amplifiers: MBL Corona C15 monoblocks, NAD M32.
Cables: Digital: AudioQuest Coffee (USB), Canare (AES/EBU). Interconnect (balanced): AudioQuest Wild Blue. Speaker: Kubala-Sosna Elation!. AC: Kubala-Sosna Elation!, manufacturers' own.
Accessories: Target TT-5 equipment racks; Ayre Acoustics Myrtle Blocks; ASC Tube Traps, RPG Abffusor panels; Shunyata Research Dark Field cable elevators; Audio Power Industries 116 Mk.II & PE-1 AC line conditioners (hard drive, computers). AudioQuest Niagara 1000 Low-Z Power/Noise-Dissipation System. AC power comes from two dedicated 20A circuits, each just 6' from breaker box.—John Atkinson

COMPANY INFO
GP Acoustics (UK) Ltd.
US distributor: GP Acoustics (US) Inc.
10 Timber Lane
Marlboro, NJ 07746
(732) 683-2356
ARTICLE CONTENTS

COMMENTS
supamark's picture

The last two photos on page 2 are not of the Reference 5. The last one is the Reference 3, the one above... dunno what it is but it ain't the Referene 5.

Also, the treble rolloff compared to the Blade 2 was interesting and unexpected.

John Atkinson's picture
supamark wrote:
The last two photos on page 2 are not of the Reference 5. The last one is the Reference 3, the one above... dunno what it is but it ain't the Reference 5.

Thanks. Replaced the final image with one more appropriate; the one above it is a closeup of the loudspeaker's outrigger base.

John Atkinson
Editor, Stereophile

supamark's picture

but I think it's a closeup of the Reference 1's stand (see link):

https://www.kefdirect.com/speakers/hi-fi-speakers/the-reference/bookshelf-speaker-stand-reference-1.html

Also, enjoyed the review, I've been curious about the differences between this and the blade 2.

Your story about the HVAC system noise reminded me of the time I recorded a visiting guitarist at The University of Texas in like '91, don't remember his name but he was quite good. I had originally gone with Neumann KM86's in crossed fig. 8 to get plenty of the room (was very nice - the reverb had a fully enveloping syrupy quality to it sitting in the audience, since ruined when they tore out the pipe organ) but forgot to take into account that it was cold/flu/allergy season - the coughing and sneezing was so bad that it was drowning out the guitarist so... at intermission (figuring the 1st half was unlistenable anyway) I ran out, moved the mics back a bit and switched them to cardiod. The artist was probably both annoyed and relieved (never heard back about it) but the 2nd half turned out quite nicely.

SMc's picture

PS UT eventually replaced the organ in the recital hall.

supamark's picture

The organ in Bates Recital Hall (interesting, adjustable acoustics in Bates) or the one in the old Music Building (the one that had the beautiful reverb)?

SMc's picture

An Aeolian-Skinner organ was installed in the old music building's Jessen Auditorium, replacing the one removed. The huge Visser-Rowland tracker in the Music Recital Hall is still going strong!

John Atkinson's picture
John Atkinson wrote:
the one above it is a closeup of the loudspeaker's outrigger base.

And I was wrong. So I have replaced that one with a cutaway picture of the Reference 5's enclosure.

John Atkinson
Editor, Stereophile

supamark's picture

ain't nobody perfect.

Edit: lookin' through, like the new photos/progression.

Ortofan's picture

... wave-guide/phase-plug an Altec-Lansing invention?
http://www.preservationsound.com/wp-content/uploads/2012/09/Altec_Model_15_18_1977.jpg

Axiom05's picture

Just curious, what is the magnitude of your resonance at ~30 Hz without smoothing? Do you have any issues with clipping at that frequency when taking your measurements with FuzzMeasure, if so, how do you deal with it to assure that the rest of the spectrum is not affected (maybe it doesn't matter)?

Cheers!

blang11's picture

I struggle to remember the last speaker review I read in Stereophile that described the sound as a bit too sweet. I recall the majority are either neutral (yay!) or overly bright or the tweeter is simply a few db too high in level. As someone who has recently moved into a room that's a bit bright, I now recognize that a bit of sweetness can be just what the doctor ordered, especially for those who recordings aren't impeccable. Great review and video interview!

foxhall's picture

I've not yet seen them in person but they look stunning in the pictures. The drivers are a work of art alone.

tonykaz's picture

These things are Beautiful.

As long as they sing nearly as well as they look they'll be big hits ( especially with the Wife's decorator).

B&O stuff is kinda overly strange looking.

Is there a more beautiful loudspeaker ?

Tony in Michigan

ps. betcha the rest of the UK speaker outfits are a bit envious.

allhifi's picture

T.I.M.: If the REF-5's are simply an extension of the REF-1's, it's a superb loudspeaker.

Personally, I believe the Reference 3 may be the best choice -and sounding.

I urge you to download and read KEF's excellent (informative) White Paper that at once is both technically astute and easy-to-read.

Not many expensive loudspeakers (to my knowledge) have and/or reveal some basic design elements; including enclosure/baffle board material composition, bracing choices, driver fastening method (KEF REF uses 6-8 BOLTS per driver -with the critical MF/HF driver no less bolted to a steel plate) and or crossover considerations -and implementations.

This and far more is discussed in this excellent White Paper.

If the equipment preceding the KEF (Reference) is up to snuff, you will be left thrilled by its sheer accuracy, delicacy, nuance, explosive dynamics and sheer realism.

peter jasz

nirodha's picture

Hi John,
I have been using the 207/2 for a loooong time and they still do it for me. How do the 2 loudspeakers compare? Bit worried about the build quality of the ref. 5. The 207/2's are build like a tank.
Cheers and all the best wishes for 2018! :-) Wim

John Atkinson's picture
nirodha wrote:
I have been using the 207/2 for a loooong time and they still do it for me. How do the 2 loudspeakers compare?

I reviewed the R207/2 in February 2008 and my system has undergone many changes since I last listened to it. But I think you still have many years ahead of you with the R207/2s. Keep 'em!

John Atkinson
Editor, Stereophile

nirodha's picture

Thanks John, keep up the good work! Wim

JimboJumbo's picture

They are a great loudspeaker.

However, in Figure 9 where you say the results suggests optimal Xover design . . .

I am not sure about that. Agreed the transition between high frequency driver and mid frequency driver, and also the transition between mid and low frequency drivers, are all reasonably smooth. But, the high frequency driver and mid frequency driver are also completely out of phase and (whilst I can see why it has been implemented that way) I am not sure that is optimal; even though it is probably not audible.

For instance, any discontinuities between the mid frequency and high frequency driver will be exacerbated by having them out of phase; and the avoidance of acoustic scattering effects at the surrounds and other areas of discontinuity within KEF’s coaxial design has been one of the evolution drivers for a long time. Perhaps you are saying the Xover design is optimized for the type of crossover/order that is implemented?

Additionally, your comment on Figure 7 . . .

“However, the Reference 5's greater directivity above 5kHz results in a response that slopes down more in the top two octaves than the Blade Two's response, and actually resembles that of the Magico S5 Mk.II, which I reviewed” . . . .

Was initially a little confusing. However, I think what you mean (please advise) is that the reference 5’s greater dispersion (rather than directivity) comes at the expense of on axis high frequency SPL.

To me, it seems there has been a design compromise, where some on axis high frequency SPL/response has been sacrificed so that off axis high frequency SPL/response performs better.

Appreciate its probably a bit of semantics between engineers, but do I have that correct. Because if I don’t then I need to know how the red trace in Figure 7 represents greater directivity.

DaveinSM's picture

While I was also surprised at the fact that the midrange is in negative polarity to the tweeter and woofer, I would think that any negative effects might be mitigated by the fact that the tweeter is located in the center of the midrange in a concentric fashion.

So this speaker design could still be time coherent (?) but not phase coherent. Even if they drivers were in the same phase, this design still wouldn't be phase coherent because the driver crossovers aren't 1st order.

I have just gotten the Reference 1 and think they sound great with great imaging. But coming from the Thiel CS3.6, which is both time and phase coherent with 1st order crossovers, I don't hear any major differences in imaging.

However, one interesting thing I do seem to be noticing is that the KEFs are a bit more forgiving of not only listening position, but also of phase in recordings. As you may know, lots of original recordings were recorded out of phase, and reversing the phase on your preamp can often make those recordings sound better. I really noticed the difference on certain recordings with the Thiels, not nearly as much so with the KEFs.

Axiom05's picture

There appears to be something odd with Figure 6, the +5 & -5 responses are flat lines while the 0 degree line is not normalized.

DaveinSM's picture

Wait- everything I’ve read about the KEF Reference series ports says that the longer ports extend low end frequency response with a gradual roll off, while the shorter ones offer a flatter bass response but with a higher, steeper LF cutoff. In effect, the shorter ones offer a punchier response but don’t go as low, so are better if the speakers are closer to the front wall.

Is what this article is saying about the port length effects consistent with this?

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