KEF owners thread

[Boba MosFET]

I'm pretty sure what's happening is that it's not a "reflection" off the floor, but a cancellation of vibrations between the speakers. In a typical room you can put a seismometer on one speaker out of a pair and then rap your knuckles on the other speaker, and that rap will show up on the seismometer. The Gaia feet prevent that. They also prevent vibrations from anything else in your house from reaching your speakers - washing machines, A/C, fridge, whatever.

However, I think if they really allow the speakers to move 1/4 inch in any direction, thats not a good thing. The reason spikes are used is they couple the speaker to the floor and prevent movement, while minimizing the contact patch (another way to reduce vibration transference between speakers). A quarter inch of movement means some of the cone movement is lost because it's being used up moving the cabinet. Some sort of blur somewhere in the frequency range will result. You're trading some clarity to product the benefit you're getting. If there is a way to prevent that movement while keeping the isolation I think that would be the way to go.

But as Ken states, if you like it, then enjoy. We're not ASR here, AK guys listen to music not meters.

 

[krautmaster]

I'm pretty sure what's happening is that it's not a "reflection" off the floor, but a cancellation of vibrations between the speakers. In a typical room you can put a seismometer on one speaker out of a pair and then rap your knuckles on the other speaker, and that rap will show up on the seismometer. The Gaia feet prevent that. They also prevent vibrations from anything else in your house from reaching your speakers - washing machines, A/C, fridge, whatever.

However, I think if they really allow the speakers to move 1/4 inch in any direction, thats not a good thing. The reason spikes are used is they couple the speaker to the floor and prevent movement, while minimizing the contact patch (another way to reduce vibration transference between speakers). A quarter inch of movement means some of the cone movement is lost because it's being used up moving the cabinet. Some sort of blur somewhere in the frequency range will result. You're trading some clarity to product the benefit you're getting. If there is a way to prevent that movement while keeping the isolation I think that would be the way to go.

But as Ken states, if you like it, then enjoy. We're not ASR here, AK guys listen to music not meters.

Apparently spiking speakers to floor is the PROBLEM that the Gaia feet correct (you'd have to read up on the science IsoAcoustics and other have done to see which vibrations they cancel) Only the top of the speaker moves 1/4", so the bottom is a fraction of that. My son said they work the same way that "earthquake proof" buildings do- floor can be rocking and vibrating all over and the speaker is not affected.

Even the ASR number lovers say they work and I'm very happy with the improvement in the sound quality.

 

[Boba MosFET]

I get what you're saying. I was looking hard at Townshend Podium stands for my Polks a while back, so I did a good long study with how that concept works. I was just hoping that anyone reading your post understands that it's not a direct wave reflection from the speaker that is being cancelled, its a vibration transmitted through the floor from each speaker to the other, and from other sources in the home through each speaker.

 

[krautmaster]

I get what you're saying. I was looking hard at Townshend Podium stands for my Polks a while back, so I did a good long study with how that concept works. I was just hoping that anyone reading your post understands that it's not a direct wave reflection from the speaker that is being cancelled, its a vibration transmitted through the floor from each speaker to the other, and from other sources in the home through each speaker.

Exactly

 

[Markoneswift]

I've made some progress on recommissioning my KEF 104/2. I had to be pretty savage with opening the cabinets in order to extract the woofers, causing some damage to the cabinets themselves and to the access panels. The reason for this is that these particular 104/2s had spent time at sea (yep, at SEA) and even though they were in a shipping container the moisture had got into all the captive bolts (of which there are many) and had rusted them all solid.

After much wailing and gnashing of teeth, I got everything apart and replaced the foam donuts on the woofers. I decided to leave the crossovers in original condition, mainly because all the parts tested OK but also I just can't afford a full refurb of them right now.

I rebuilt some of the damaged cabinet areas with 2 part filler (aka bog, bondo etc) and installed all new captive nuts and bolts. Some of the grazes on the cabinet edges are covered by the huge front covers so that's quite lucky!

 

[HiFi in WYO]

Bag o' capacitors arrived last week from Falcon Acoustics across the pond. Once the snow flies (which could be any day now) I'll start recapping the 105.1s and bring them back to the front of the line. Nice people over there, respond quickly and shipping wasn't that long. Jeesh, there's a lot of caps in that bag.

 

[rickb119]

Bag o' capacitors arrived last week from Falcon Acoustics across the pond. Once the snow flies (which could be any day now) I'll start recapping the 105.1s and bring them back to the front of the line. Nice people over there, respond quickly and shipping wasn't that long. Jeesh, there's a lot of caps in that bag.

Have fun, and be sure to let us know the results/improvements.

The snow does indeed 'fly' in Wyoming. Often, horizontally.

 

[DOBIEGUY]

Quote:

“Once the snow flies (which could be any day now) I'll start recapping the 105.1s and bring them back to the front of the line.”

Why wait? Do it now. This way when the ‘snow flies’ you can kick back, maybe enjoy a nice libation and forget about the long, ugly weather ahead.
Happy listening!
(from a long time KEF owner)

 

[HiFi in WYO]

Too much to do right now and the weather's nice. But we'll see. Still enjoying the restored AR 93Qs - gawd those are nice as well.

 

[rothwellaudio]

OK, I'll bite...what difference do the Isoacoustics Gaia II feet make for you?

They got rid of a secondary reflection coming off the hardwood floor, making the bass/mid bass tighter.

I for the life of me cannot fathom how isolation pads under speakers could "rid of a secondary reflection coming off a hardwood floor."

Apparently the reflection was going back up into the speakers.

I was first introduced to the concept of isolating speakers by compliant mounting over thirty years ago by an article in a studio and home recording magazine. The concept was that the speed of sound in wood/concrete/metal is much higher than it is in air, so sound from the speakers arrives at the listener via transmission through the structure of the building before it arrives directly through the air. Cutting out the structure-borne vibrations by isolating the speakers with some kind of compliant mounting fixed the problem, or so it was claimed, so I though I'd give it a try. Yep, it worked for me - cleaner bass.
My isolation was a cheap DIY affair using springs, something similar to what Townshend Audio sell now.

SEISMIC ISOLATION PODIUMS – Townshendaudio

townshendaudio.com

Mine was very cheap - very, very. very cheap compared to the Townshend products.
Btw, speaker isolation is commonplace in the studio world, usually achieved at a fairly modest cost by using foam under the speakers.

 

[mark_m]

We have a pair of Coda 90's in the family.They were for our living room but I loaned them to one of my kids and he soon let me know he was keeping them

 

[Ken Mitchell]

I thought it would be cool to share a 12 second video I took, one of my Blade 2 Meta speakers doing a somewhat well-known parlor trick.

KEF themselves often do this demonstration at audio shows and dealer events, though I had never actually seen it done myself, nor any video of it. Well here you go, I got it! I had to keep it under 20 seconds or YouTube would take it down because I don't have permission to use a tune from The Rolling Stones album "Black And Blue."

It's a US currency 5¢ piece, our nickel being a thicker smooth-edged coin. Definitely shows just how inert the cabinets are and how effective the 4 opposed woofers cancel their own vibrations.


KEF Blade 2 Meta parlor trick

 

[Lou G]

Hey Ken,
I have done that many times with all of my KEF speakers. I remember once I had a nickel sitting on my KEF Calindas for several hours listening to numerous tracks, some with deep bass, at various sound levels and it never fell or moved.

 

[Ken Mitchell]

Hey Ken,
I have done that many times with all of my KEF speakers. I remember once I had a nickel sitting on my KEF Calindas for several hours listening to numerous tracks, some with deep bass, at various sound levels and it never fell or moved.

It's a bit more challenging with a Blade cabinet because there's no flat surfaces!!

 

[Lou G]

It's a bit more challenging with a Blade cabinet because there's no flat surfaces!!

Yes, I realize that after I looked at how the Blades are angled on the top surface. I assumed there was a flat section on top. I am surprised you could even get the nickel to sit without falling.

 

[arts]

Hello all,

Anybody have a schematic for the KEF Reference Model Four crossover?

Thanks!

 

[krautmaster]

I tried the "balance a nickel on the top of the speaker" thing... all my speakers with Iso Acoustics Gaia feet passed the test with flying colors, even with the volume cranked up to 90 db (KEF R7 Meta, Monitor Audio Silver 500's, Infinity RS4b) but the pair of Monitor Audio Silver 100 bookshelf speakers that I have on 26" tall metal stands didn't make it past the first heavy bass note before the nickel took a dive...

I'm almost positive the ancient RS4b's would have failed easily without the Gaia feet (big open boxes with no bracing, but stuffed full of insulation and fiber fill) I think the MA Silver 500's would have done fine, and am positive the KEFs would have had no issues either)

 

[Boba MosFET]

I tackled a refurb on a pair of Reference Model Three recently. Blown NT25 tweeters required rebuild (no replacements available), and I installed a Falcon kit. Now I have to rebuild several of the B200 woofers, SP1343. I doubt I'll be able to cleanly separate the rubber surrounds so they'll have to be replaced. No one offers replacement rubber surrounds for these so I'll have to go with foam. I understand KEF, like every other speaker manufacturer, can't be expected to stock replacements for long-discontinued drivers, but given the massive sea changes in on-demand manufacturing these past few years it would be nice if they offered some sort of path for their fans to get vintage speakers working again.

 

[decreed_it]

hey all, new to the forum, and new to me KEF 104aBs - couple 'before' pics. They sound fantastic driven by also-new-to-me Luxman L-580 and have had some previous work, but they're at the HiFi shop for 'anything they need' regardless. I'll post afters when I get them back. Getting new screens made as well.

 

[seannc]

hey all, new to the forum, and new to me KEF 104aBs - couple 'before' pics. They sound fantastic driven by also-new-to-me Luxman L-580 and have had some previous work, but they're at the HiFi shop for 'anything they need' regardless. I'll post afters when I get them back. Getting new screens made as well.

View attachment 3762369View attachment 3762370

Congratulations! I was given a pair of 104s and found aB Kit crossovers on eBay years ago. I purchased the replacement capacitors from Falcon Acoustics. The upgrades were definitely worthwhile and they're a great pair of speakers. I've since purchased a pair of Joseph Audio speakers, but I tell you these old KEFs stand up well. You'll have years of enjoyment!