Radiant Acoustics Clarity 66 Speaker Review

[Lars Risbo]

me too

Edit: but i actually have heard such thing. 2x10” + 4x10”PR +2x5” + 1.3” per side. Triple amped and DSP/Accurate processing

 

[amirm]

@amirm
Are we sure the LF is correct? there is an unusual step at 100Hz?

It is unusual but we see it with direct measurement of the port:

There is a resonant peak around 105 Hz in the port (brown). The woofer response also has fine dips so they probably lined up accidently causing that step response.

 

[Matt_Holland]

me too

Edit: but i actually have heard such thing. 2x10” + 4x10”PR +2x5” + 1.3” per side. Triple amped and DSP/Accurate processing

And?????

 

[Lars Risbo]

yes, it’s the fundamental standing wave of the box and it leaks both out of the port and woofers and sum up as a little shelf. it was just a little higher up in frequency in our measurements on a preproduction unit.

 

[Salt]

me too

Edit: but i actually have heard such thing. 2x10” + 4x10”PR +2x5” + 1.3” per side. Triple amped and DSP/Accurate processing

Wearing the hair open really suits You

 

[amirm]

yes, it’s the fundamental standing wave of the box and it leaks both out of the port and woofers and sum up as a little shelf. it was just a little higher up in frequency in our measurements on a preproduction unit.

Was it you or Bruno who said that with the much higher accuracy of Klippel NFS scanner, we now have to fix problems that were never seen in reviews before?

 

[Lars Risbo]

Thanks, but it belongs to my dear wife

 

[Salt]

yes, it’s the fundamental standing wave of the box and it leaks both out of the port and woofers and sum up as a little shelf. it was just a little higher up in frequency in our measurements on a preproduction unit.

Did You evaluate using a Helmholtz Resonator for coping with this problem?

 

[Duke]

... we avoid having a crossover point in the lower mid range that would add group delay and make the main lobe point down towards the floor (a general 2.5 way issue ).

This. Lobe tilt is sort of like a dirty little secret of 2.5 way designs.

 

[Lars Risbo]

Did You evaluate using a Helmholtz Resonator for coping with this problem?

I have simulated many configurations of using resonators to kill the standing wave. however, all these scheme beautifully kill the standing mode but introduce a new mode deeper down which is even harder to damp out. All the speakers i have seen claiming this trick have visible resonances on the impedance curve which does not lie.

 

[Lars Risbo]

Was it you or Bruno who said that with the much higher accuracy of Klippel NFS scanner, we now have to fix problems that were never seen in reviews before?

could have said it. we can’t design anything better than we can measure. full stop.

 

[thewas]

I have simulated many configurations of using resonators to kill the standing wave. however, all these scheme beautifully kill the standing mode but introduce a new mode deeper down which is even harder to damp out. All the speakers i have seen claiming this trick have visible resonances on the impedance curve which does not lie.

Another approach is to place the woofers so that it's reduced, works though rather well for 3-ways as there you have more freedom in their placement.
https://www.audiosciencereview.com/forum/index.php?threads/kef-q-series-with-mat-whitepaper.57911/ (page 8 of the linked paper)

 

[Lars Risbo]

Could not read it on my phone but KEF has s long tradition for placing the driver in a node and thus avoid energising the mode(s). this was not possible here and the port is placed away from the woofers to attenuate the midrange leakage and port pipe modes. A symmetric woofer placement and the port in the middle would avoid the fundamental mode completely

 

[Salt]

Another approach is to place the woofers so that it's reduced, works though rather well for 3-ways as there you have more freedom in their placement.
https://www.audiosciencereview.com/forum/index.php?threads/kef-q-series-with-mat-whitepaper.57911/ (page 8 of the linked paper)

This (first 1/3 of the line to postion the transducers), in combination with a Helmholtz Resonator.
Might look it up, but with Bernd Timmermann's constructions there was no hint for some distorsions in lower frequencies via these tecnique. Not in FR nor within the impedance plot.

 

[kimmosto]

make the main lobe point down towards the floor (a general 2.5 way issue )

Passive MTM (or active with IIR XO) where 0.5 driver is higher turns the main axis upward at lower mid. I saw that design ca. four decades ago in some Finnish DIY speaker by P. Tuomela, but unlikely used it in my designs because speakers with dual mid have been more complex; more ways, more or large woofers, directive bass etc. to maintain stronger directivity and lower DI slope to LF.
One interesting point is that main axis turning down (or up) at low mid has sounded excellent imo. Adequate power at lower mid sounds more natural (imitating DI of human voice and instruments) than too flat but still quite low total directivity. So I'm not the biggest fan of constant DI concept without balancing ON and LW so that power at low and mid remains high enough compared to highs.
Sorry about OT.

 

[Duke]

we can’t design anything better than we can measure. full stop.

First, THANK YOU for sharing so much valuable information about the design choices you have made. Yes, I've been taking notes!

So please do not feel obligated to share anything in this area: Are there particular measurements that you look to as predictive of spatial quality?

 

[Mort]

This seems similar to the Philharmonic HT Tower, which is a favorite of mine in the bang for the buck category.

 

[Penelinfi]

This seems similar to the Philharmonic HT Tower, which is a favorite of mine in the bang for the buck category.

The clarity 66 likely has deeper bass output whereas the HT tower rolls off a bit earlier for higher sensitivity/loudness. It is presumed people will have subs in HT of course. I forgot exactly how the HT measured now

 

[Endibol]

Circular bike race.

LOL.

Welcome back @restorer-john ! I really missed your slightly cynical but knowledgeable comments

 

[Lars Risbo]

The clarity 66 likely has deeper bass output whereas the HT tower rolls off a bit earlier for higher sensitivity/loudness. It is presumed people will have subs in HT of course. I forgot exactly how the HT measured now

correct, Dennis prioritised sensitivity over bass extension since everyone in HT uses subs. two W woofers used.