KEF Ci250RRM

[voodooless]

What’s the difference?

A few meters of additional baffle. That is big difference.

 

[sarumbear]

Baffle step response?

Understood but that’s not necessarily the box but how the speaker is mounted. You can put the driver in a box and soffit mount it. After all the wall cavity is a box.

 

[voodooless]

So back to my question... how do you build the wall/ceiling to not ruin the speaker? Resilient channel is not rated to support the load of a normal speaker, especially in the ceiling, and this is not a normal speaker. It weighs twice as much as the rest of their architectural line..

Don't know, ask your installer or contractor... It weights 6 KG, I doubt that will be a big issue for 12mm drywall. Otherwise, double up the baffle to be sure. You can also build a box in the wall and drywall over it. Lot's of options...

 

[voodooless]

Understood but that’s not necessarily the box but how the speaker is mounted. You can put the driver in a box and soffit mount it.

How it is supposed to be mounted, is what the crossover was designed for. It probably has no baffle step compensation. It will sound thin if you mount it in a normal box.

 

[sarumbear]

How it it mounted, is what the crossover was designed for. It probably has no baffle step compensation. It will sound thin if you mount it in a normal box.

What is a “normal box?” What type of box do you think it is designed for?

 

[voodooless]

What is a “normal box?” What type of box do you think it is designed for?

It's not, that is the point!

 

[sarumbear]

How it it mounted, is what the crossover was designed for. It probably has no baffle step compensation. It will sound thin if you mount it in a normal box.

What is a normal box? What type of box do you think it is designed for?

It's not, that is the point!

I lost you. Any speaker that is mounted on a baffle that covers a defined area and is away from a solid wall has a volume. It’s effectively the enclosure. That volume only affects the Qt and fc of the driver. As this is a in-wall or in-ceiling speaker it means it’s designed to work on a 2pi load irrespective of the enclosure.

 

[voodooless]

I lost you. Any speaker that is mounted on a baffle that covers a defined area and is away from the solid wall has a volume. It’s effectively the enclosure. That volume only affects the Qt and fc of the driver. As this is a in-wall or in-ceiling speaker it means it’s designed to work on a 2pi load irrespective of the enclosure.

I think the confusion here is shape vs volume. Obviously, this thing needs a volume of 80 to 150 liters. I'm talking about the shape of the thing. A box shape is different from a large baffle a ceiling would form. It will have a totally different baffle step behavior. Mounting this thing in a conventional box shape will need baffle step compensation as a minimum.

 

[sarumbear]

I think the confusion here is shape vs volume. Obviously, this thing needs a volume of 80 to 150 liters. I'm talking about the shape of the thing. A box shape is different from a large baffle a ceiling would form. It will have a totally different baffle step behavior. Mounting this thing in a conventional box shape will need baffle step compensation as a minimum.

This is an in-wall speaker. It will always have a large baffle compared to, for instance, a bookshelf speaker. The shape of the enclosure has no effect whatsoever. A volume is a volume. It doesn’t matter what the box dimensions are.

 

[voodooless]

This is an in-wall speaker. The shape of the enclosure has no effect whatsoever. A volume is a volume. It doesn’t matter what the box dimensions are.

I repeat it's not about the volume! @Descartes wanted to put this thing in a standalone speaker, aka, a box.. One of those that looks like a box from the outside:

So what volume would I need to make these as stand alone speakers?

 

[sarumbear]

@Descartes wanted to put this thing in a standalone speaker, aka, a box.. One of those that looks like a box from the outside:

I’m sorry I didn’t realise that. Short and not fully formed replies was not helping.

He shouldn’t do that unless he plans to use EQ.

 

[abdo123]

What’s the difference?

Also it’s not flat on-axis. It’s meant to be listened at at least 45 degrees off-axis

 

[sarumbear]

Also it’s not flat on-axis. It’s meant to be listened at at least 45 degrees off-axis

It is indeed odd that there’s no on axis response given.

 

[Slick Minkus]

Also it’s not flat on-axis. It’s meant to be listened at at least 45 degrees off-axis

Isn't this consistent with most of KEF's Uni-Q tunings - regardless of baffle size?

I think the confusion here is shape vs volume. Obviously, this thing needs a volume of 80 to 150 liters. I'm talking about the shape of the thing. A box shape is different from a large baffle a ceiling would form. It will have a totally different baffle step behavior. Mounting this thing in a conventional box shape will need baffle step compensation as a minimum.

Agreed, and it should be a relatively easy task with the high 540Hz bass-driver crossover on a new baffle dictated by the 10" driver housing.
Usually one should expect to do the work when repurposing any driver configuration - compensating for every variable they've introduced (baffle size, baffle shape, distance from the edges, volume, etc.). KEF have however made the prospect pretty damn simple with the amount of engineering that's gone into this design.

So what volume would I need to make these as stand alone speakers? I am seriously considering making them with just one Ci250RRM!
Could they be open baffle?

Most bass drivers have their stiffness designed with a back box in mind, but this configurations' bass driver is designed for an infinite baffle and therefore might actually be relatively well suited to open baffle. With that said, this is a 10" driver with unknown excursion limits so you would definitely have similar if not worse low bass challenges one should expect in an open baffle configuration.
Also, you would have to rear mount an additional UNI-Q driver on the back if you wanted a bi/dipole effect as the 'tweeter and midrange driver are mounted in an airtght housing which is positioned a distance away from the LF driver.'.

 

[dshreter]

Isn't this consistent with most of KEF's Uni-Q tunings - regardless of baffle size?

No, for example R3 is flat on axis.

 

[Slick Minkus]

No, for example R3 is flat on axis.

I stand corrected, it's a massive difference!
One would definitely have to do the work to repurpose this configuration.

 

[dshreter]

I stand corrected, it's a massive difference!
One would definitely have to do the work to repurpose this configuration.

If you aimed them straight on instead of at the listening position, that’s 30 degrees off axis. Straight on placed against the wall would look pretty slick

 

[Lbstyling]

This is true

If you aimed them straight on instead of at the listening position, that’s 30 degrees off axis. Straight on placed against the wall would look pretty slick

Also, most/many users here would be using an AV amplifier or EQ anyway.

I for one would not be concerned with the on axis rise, as I would be mounting them in my front wall as L+R speakers which I listen to at about 20 degrees off axis anyway.

The distortion at higher SPLs it the thing I want to know about. 4 inch mid is considerably smaller surface area vs the 5.25 of most KEF coax drivers.

The LS60 hits 110db, with the same size driver, but at unknown distortion figures, so there is some hope.

We need a test on at least one of these 2 speakers.

 

[Descartes]

Ci250RRM-THX

Featuring innovative technologies including 12th Generation Uni-Q® driver array with Metamaterial Absorption Technology (MAT), patent-pending Cavity Radiation Control and Low Diffraction LF Aperture, Ci250RRM-THX is a truly revolutionary coaxial three-way architectural speaker that delivers...

us.kef.com

2200 USD a piece...likely not a coincidence the same price as Synthesis SCL-5.

The one thing I'm not seeing is any angle or way to aim the Uni-Q towards the listening position. I hope I just missed it, because that's IMO a requirement for height speakers in an immersive system. And otherwise these appear to tick all the boxes and then some.

Whoa that’s very expensive for ATMOS speakers!
Better used as surround

 

[Descartes]

Whoa that’s very expensive for ATMOS speakers!
Better used as surround

They are too thick for surround speakers