KEF Q Series with MAT Whitepaper

[Joe Smith]

Not having a measurement mic (and not really wanting to go down that Rabbit Hole, for me), I tested a few variables and found that this degree of adjustment works well for me with these older Q speakers. Quite a noticeable impact with the jazz I've been playing this morning!

 

[K man]

@pthakkar24, how come there is no FR for the Q8 Meta? I would be very happy to see it and see how it compares to the R8 Meta.

There seems to be a slight dent in the impedance around 1.1kHz, indicating a potential resonance there.

Do you have a FR of the Q8 Meta that you could share?

 

[pierre]

KEF sent me the data for all the speakers in the Q Meta Generation. They are uploaded to spinorama.org where you will find all the gory details.

Thanks @pthakkar24

As always, the concordance between Erin with a Klippel NFS measurement and KEF with a quasi anechoic measurement is excellent.

 

[K man]

KEF sent me the data for all the speakers in the Q Meta Generation. They are uploaded to spinorama.org where you will find all the gory details.

I checked it out, but I can't seem to find any data or listing for the Q8 Meta model.

 

[pierre]

I checked it out, but I can't seem to find any data or listing for the Q8 Meta model.

You are correct. I didnt get this one.

 

[pthakkar24]

KEF sent me the data for all the speakers in the Q Meta Generation. They are uploaded to spinorama.org where you will find all the gory details.

Thanks @pthakkar24

As always, the concordance between Erin with a Klippel NFS measurement and KEF with a quasi anechoic measurement is excellent.
View attachment 416411View attachment 416412

Thanks @pierre, appreciate your help!

@K man You’re right, the Q8 Meta’s frequency response isn’t included in the Spinorama data or Whitepaper. This is because this speaker is specifically designed to meet Dolby specifications, within which restricted directivity is a key requirement for this product category. Due to this, the ATMOS product specifications don’t align with the performance metrics typically inferred from Spinorama curves.

It’s also worth noting that the reference axis for this product, 0 degrees on tweeter axis, is not the same as 0 degrees directly in front of the speaker, and a large degree of attenuation is expected between the two by design.

That said, I’d be happy to share the on-axis frequency response data once I’m back from Christmas break so you can verify whether the performance is to your liking.

Thanks!

 

[amarsicola]

Hi @pthakkar24 any chance that a Qmeta tower is sent to Erin or Amir for review?

 

[MarcT]

Hi @pthakkar24 any chance that a Qmeta tower is sent to Erin or Amir for review?

Yes, I'm now going between Q11 Meta and Martin Logan Motion Foundation F2, which are on sale. I'd like to see measurements on both of them.

 

[K man]

@K man You’re right, the Q8 Meta’s frequency response isn’t included in the Spinorama data or Whitepaper. This is because this speaker is specifically designed to meet Dolby specifications, within which restricted directivity is a key requirement for this product category. Due to this, the ATMOS product specifications don’t align with the performance metrics typically inferred from Spinorama curves.

It’s also worth noting that the reference axis for this product, 0 degrees on tweeter axis, is not the same as 0 degrees directly in front of the speaker, and a large degree of attenuation is expected between the two by design.

That said, I’d be happy to share the on-axis frequency response data once I’m back from Christmas break so you can verify whether the performance is to your liking.

Thanks. I really appriciate that.

I figured the reason was probably because those are a special category of speakers and that the angle of the drivers means some special considerations regarding the measurements. Still, I would argue that the on tweeter axis measurements are equally important as to other speakers. At least if you intend to use them as height speakers, which I do.

Is there any possibility for you to also share some distortion meansurements? The R8 Meta were measuring excellent, and considering that the drivers are very similar* I'm not concerned about driver distortion, but that dent near 1.1Hz in impedence indicate a potential resonance that could be of concern.

* It seems that the drivers are exactly the same as in the R8 Meta, besides that the MAT has been simplified into a single layer instead of dual layers. Is that correct?

 

[amarsicola]

Spoiler: Erin is going to test the Q11 metas

 

[pthakkar24]

Thanks. I really appriciate that.

I figured the reason was probably because those are a special category of speakers and that the angle of the drivers means some special considerations regarding the measurements. Still, I would argue that the on tweeter axis measurements are equally important as to other speakers. At least if you intend to use them as height speakers, which I do.

Is there any possibility for you to also share some distortion meansurements? The R8 Meta were measuring excellent, and considering that the drivers are very similar* I'm not concerned about driver distortion, but that dent near 1.1Hz in impedence indicate a potential resonance that could be of concern.

* It seems that the drivers are exactly the same as in the R8 Meta, besides that the MAT has been simplified into a single layer instead of dual layers. Is that correct?

No problem, there you go!

The second graph is normalised THD level (or THD Ratio in dB) compared to fundamental. I've also included horizontal lines for 1 and 2% THD ratio thresholds for easy reference (same as the product specs on the website). Note the input level is higher than 2.82V so the passband level here is higher than the rated sensitivity of 86dB.

Q8 Meta driver is based on the Q1 Meta Uni-Q (we design new Uni-Qs for every product range) and has a single layer MAT as opposed to the two layer MAT in the R8 Meta.

For completeness, the R series Uni-Q used in the R8 Meta is a considerably higher performance driver due to a more sophisticated motor design with a split top plate, as well as an underhung voice coil design - more details in the R Series with MAT whitepaper if you are interested. https://images.salsify.com/image/upload/s--_1LKGFsv--/new97sn5l4dtqcjadqeo.pdf

Cheers!

 

[thewas]

Now that is an exemplary transparency, it shines out when a company has nothing to hide.

 

[K man]

No problem, there you go!

The second graph is normalised THD level (or THD Ratio in dB) compared to fundamental. I've also included horizontal lines for 1 and 2% THD ratio thresholds for easy reference (same as the product specs on the website). Note the input level is higher than 2.82V so the passband level here is higher than the rated sensitivity of 86dB.

Q8 Meta driver is based on the Q1 Meta Uni-Q (we design new Uni-Qs for every product range) and has a single layer MAT as opposed to the two layer MAT in the R8 Meta.

For completeness, the R series Uni-Q used in the R8 Meta is a considerably higher performance driver due to a more sophisticated motor design with a split top plate, as well as an underhung voice coil design - more details in the R Series with MAT whitepaper if you are interested. https://images.salsify.com/image/upload/s--_1LKGFsv--/new97sn5l4dtqcjadqeo.pdf

Cheers!

View attachment 417540View attachment 417541

Lovely!

It looks better than I had expected. Sure, the distortion is not as low as for the R8 Meta, but still low and more smooth than I thought it would be, and the frequency response actually looks better than for the R8 Meta.

You said the driver is based on the one in the Q1 Meta. Does that mean the directivity is also similar, or the Q8 has a different tuning due to the Atmos requirements? (Perhaps we could have the on tweeter axis spinorama uploaded to spinorama.org?)

By the way, just to make you aware, there are wrong images shown for the Q8 Meta with grilles on your website.