Radiant Acoustics Clarity 66 Speaker Review

[Lars Risbo]

for comparison the F328Be:

it rolls off the bass from 100Hz and the F10 is as high as around 40Hz. It’s tuned very low which gives this roll off but it helps keeping the excursion low above 30Hz. We only have this 96dB mid band spl HD plot but it looks good. but keep in mind that the SPL at 30Hz is much lower due to the strong roll off. Again, the 66 would probably beat it at a level normalised comparison at eg 30 Hz at a higher SPL.

 

[Cote Dazur]

Distortion in speakers is also very apparent if you are used to listening to low-distortion headphones/IEMs

Excellent point.

After reading the review and the conversation in this thread, I wish I could afford those speakers, for the first time in over 30 years, it sounds like something really interesting at a price point that seems justified by the performance.
Here is to see a baby version at a price I can afford. Ultra low distortion in speaker is the future.

 

[Space is the place]

Thanks Mr Risbo for your reply into what got you into electronics and speaker design, seems like the die was cast from and early age! I'm looking forward to hearing them.
Just one more question if i may, is the front of the speaker, both the upper and lower baffle aluminum? It doesn't mention it in the review above, thank you.

 

[smokeymackinsey]

Thanks Mr Risbo for your reply into what got you into electronics and speaker design, seems like the die was cast from and early age! I'm looking forward to hearing them.
Just one more question if i may, is the front of the speaker, both the upper and lower baffle aluminum? It doesn't mention it in the review above, thank you.

Both parts of the baffle are 15mm CNC'd aluminum parts

 

[Lars Risbo]

Here is my take on the EQ.
Please report your findings, positive or negative!

For the score rational your journey starts here
Explanation for the sub score
The following EQs are “anechoic” EQs to get the speaker right before room integration.
If you able to implement these EQs you must add EQ at LF for room integration, that is usually not optional… see hints there.

The raw data with corrected ER and PIR:

Score no EQ: 5.2
With Sub: 7.1

Spinorama with no EQ:

• Not smooth poor vertical directivity
• a few resonances
• HF ragged
• Ascending LW

View attachment 547589
Directivity:

Better stay at tweeter height
Horizontally, better toe-in the speakers by 10/15deg and have the axis crossing in front of the listening location, might help dosing the upper range. Explanation here.
View attachment 547596View attachment 547603

EQ design:
I have generated two EQs. The APO config files are attached.

• The first one, labelled, LW is targeted at making the LW flat
• The second, labelled Score, starts with the first one and adds the score as an optimization variable (here).
• The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.
• One can model the EQ with Vituixcad by using the DSP "Generic" setting with 96000Hz sampling rate.
• Just Score EQ as it is essentially the same as LW

View attachment 547594
Score no EQ: 5.2
With Sub: 7.1

Score EQ Score: 6.6
with sub: 8.3

Radiant Acoustics 66 APO Score EQ 96000Hz
July282026-121718

Preamp: -3.00 dB

Filter 1: ON HPQ Fc 34.9 Hz Gain 0.00 dB Q 1.31
Filter 2: ON PK Fc 568.5 Hz Gain -2.06 dB Q 6.00
Filter 3: ON PK Fc 918.5 Hz Gain -2.29 dB Q 5.50
Filter 4: ON PK Fc 1000.1 Hz Gain 1.88 dB Q 0.88
Filter 5: ON PK Fc 1548.4 Hz Gain -0.31 dB Q 6.00
Filter 6: ON PK Fc 5612.9 Hz Gain -0.96 dB Q 2.97
Filter 7: ON PK Fc 6759.2 Hz Gain 2.12 dB Q 4.15
Filter 8: ON PK Fc 8207.1 Hz Gain -2.41 dB Q 4.94
Filter 9: ON PK Fc 10760.7 Hz Gain 2.33 dB Q 3.16
Filter 10: ON PK Fc 12152.6 Hz Gain -2.42 dB Q 3.07

Spinorama EQ Score
View attachment 547590

Zoom PIR-LW-ON
View attachment 547593

Regression - Tonal
View attachment 547592

Radar no EQ vs EQ score
Some improvements?
View attachment 547591

hi, do you plan to update with the updated measurments? The bass would not need that bass lift.

cheers

Lars

 

[mrick39]

Hummmm actually the Taipuu Kero L Active Pro towers use 4x Purifi Audio woofers @6800€ paired (instead of 13600€)

Taipuu Kero L Active Pro - Aalto Speakers

Loistava tilaisuus tarttua viimeisiin Taipuu Kero L Active Pro -lattiakaiuttimiin suoraan valmistajan varastosta uskomattomaan hintaan! Saatavilla enää yksi pari satiininvalkoisena.

aaltospeakers.fi

Two woofers and four PR's per speaker

 

[daniboun]

Two woofers and four PR's per speaker

Right )
Drivers: Purifi Audio 6.5" bass-midrange 2pcs, Purifi Audio 6.5" passive radiators 4pcs, and SB Acoustics 29mm Beryllium dome

 

[suttondesign]

Distortion in speakers is also very apparent if you are used to listening to low-distortion headphones/IEMs.

yup, and I do. truthear reds and those planars from hidisz mp145 or whatevs.

 

[kimmosto]

Two woofers and four PR's per speaker

Right )
Drivers: Purifi Audio 6.5" bass-midrange 2pcs, Purifi Audio 6.5" passive radiators 4pcs, and SB Acoustics 29mm Beryllium dome

Some design simulations of Active Pro version (full active 2.5-way with linear-phase XOs).

Semi-active version with single 4-channel amp, IIR filters and passive 0.5 XO is also designed, but not manufactured:

Purifi drivers are not very suitable for passive 2.5-way due to low baffle loss producing "too linear" frequency response. I guess this is one of the reasons why Clarity 66 is 2-way though generally 2.5-way (proposed by @thewas ) can provide smoother directivity ~ more natural sound balance.

As already mentioned, 6800 €/pair is low profit sale price for the last two pairs. One pair left. Model is discontinued though it's possible to continue because components are still available.

 

[Jonazkur]

Alot of ppl complaining about the price here,which i dont understand. 8000€ isnt much for these imo with the component/build quality you get in commercial product. There is always the possibility to build diy speakers if you want cheaper. You can get this kind or better performance for about 2000€ with diy route.

 

[daniboun]

Alot of ppl complaining about the price here,which i dont understand. 8000€ isnt much for these imo with the component/build quality you get in commercial product. There is always the possibility to build diy speakers if you want cheaper. You can get this kind or better performance for about 2000€ with diy route.

It’s all relative... a quick look at spinorama.org with the right filter will show you plenty of contenders under $2,000 that perform better.

 

[Jonazkur]

Ehi

It’s all relative... a quick look at spinorama.org with the right filter will show you plenty of contenders under $2,000 that perform better.

Which ones and where do they perform better?

 

[Waxx]

it focusses on one factor, distortion, and does it very good in minimising it, but it's frequency response and dispertion are far from perfect. It's a good try, but to be worth that kind of money i would need that that is also as good. Otherwise i rather get a Neumann KH420 that cost as much in Europe, but is a lot better in general and include amps.

 

[Jonazkur]

it focusses on one factor, distortion, and does it very good in minimising it, but it's frequency response and dispertion are far from perfect. It's a good try, but to be worth that kind of money i would need that that is also as good. Otherwise i rather get a Neumann KH420 that cost as much in Europe, but is a lot better in general and include amps.

Neumann looks good yes. Active speakers seem to have better value. But not everyone wants an active speaker. On passive market radiant acoustics isnt that expensive.

 

[Maiky76]

hi, do you plan to update with the updated measurments? The bass would not need that bass lift.

cheers

Lars

Here you are.

Original:

Radiant Acoustics Clarity 66 Speaker Review

That would be my ideal speaker. External electronics with one amp to control one drive, all orchestrated and controlled by an DSP. JBL's M2 system is a good blueprint. As a non-DIYer, it would be cool to see a similar, commercially available system based on MiniDSP, Purifi amps, Purifi...

www.audiosciencereview.com

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

@Lars Risbo
Is there a perforated partition in the LF cavity e.g.:

No EQ spinorama:

New EQ:

Radiant Acoustics Clarity 66 Correct LF APO Score EQ 96000Hz
August012026-155932

Preamp: -2.60 dB

Filter 1: ON HPQ Fc 33.7 Hz Gain 0.00 dB Q 1.20
Filter 2: ON PK Fc 84.3 Hz Gain 1.31 dB Q 1.62
Filter 3: ON PK Fc 563.9 Hz Gain -2.21 dB Q 6.00
Filter 4: ON PK Fc 937.2 Hz Gain -1.62 dB Q 4.30
Filter 5: ON PK Fc 1111.8 Hz Gain 1.99 dB Q 0.87
Filter 6: ON PK Fc 1252.3 Hz Gain -1.01 dB Q 6.00
Filter 7: ON PK Fc 5626.9 Hz Gain -0.96 dB Q 2.93
Filter 8: ON PK Fc 6763.5 Hz Gain 2.12 dB Q 4.15
Filter 9: ON PK Fc 8197.1 Hz Gain -2.46 dB Q 4.94
Filter 10: ON PK Fc 10764.7 Hz Gain 2.24 dB Q 2.74
Filter 11: ON PK Fc 12167.1 Hz Gain -2.47 dB Q 3.35

Wrong LF:
Score no EQ: 5.2
With Sub: 7.1

Wrong LF:
Score EQ Score: 6.6
with sub: 8.3

New LF
Score no EQ: 6.0
With Sub: 7.0

New LF
Score Score EQ: 7.1
With Sub: 8.3

 

[Lars Risbo]

Here you are.

Original:

Radiant Acoustics Clarity 66 Speaker Review

That would be my ideal speaker. External electronics with one amp to control one drive, all orchestrated and controlled by an DSP. JBL's M2 system is a good blueprint. As a non-DIYer, it would be cool to see a similar, commercially available system based on MiniDSP, Purifi amps, Purifi...

www.audiosciencereview.com

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

@Lars Risbo
Is there a perforated partition in the LF cavity e.g.:
View attachment 548561


No EQ spinorama:
View attachment 548543
New EQ:
View attachment 548548

Radiant Acoustics Clarity 66 Correct LF APO Score EQ 96000Hz
August012026-155932

Preamp: -2.60 dB

Filter 1: ON HPQ Fc 33.7 Hz Gain 0.00 dB Q 1.20
Filter 2: ON PK Fc 84.3 Hz Gain 1.31 dB Q 1.62
Filter 3: ON PK Fc 563.9 Hz Gain -2.21 dB Q 6.00
Filter 4: ON PK Fc 937.2 Hz Gain -1.62 dB Q 4.30
Filter 5: ON PK Fc 1111.8 Hz Gain 1.99 dB Q 0.87
Filter 6: ON PK Fc 1252.3 Hz Gain -1.01 dB Q 6.00
Filter 7: ON PK Fc 5626.9 Hz Gain -0.96 dB Q 2.93
Filter 8: ON PK Fc 6763.5 Hz Gain 2.12 dB Q 4.15
Filter 9: ON PK Fc 8197.1 Hz Gain -2.46 dB Q 4.94
Filter 10: ON PK Fc 10764.7 Hz Gain 2.24 dB Q 2.74
Filter 11: ON PK Fc 12167.1 Hz Gain -2.47 dB Q 3.35

Wrong LF:
Score no EQ: 5.2
With Sub: 7.1

Wrong LF:
Score EQ Score: 6.6
with sub: 8.3

New LF
Score no EQ: 6.0
With Sub: 7.0

New LF
Score Score EQ: 7.1
With Sub: 8.3


View attachment 548545
View attachment 548544

thanks!

No we don’t use perforated plates although i find the idea intriguing. the box is lined with 70mm iCell.

100Hz step: yes a bit strange. My own measurements show a little shelving step at 130Hz at the standing wave in the box. A bit strange if this moved down to 100Hz.

 

[see_no_evil]

it focusses on one factor, distortion

that's not what I read in a review:

Rest of the measurements are good to very good. Slight imperfections are seen here and there which seem to bother the eye more than the ears. For me anyway.

Let's not downplay what is a very competent speaker design with some outstanding qualities, not to mention visual design that will be at home in a modern apartment, unlike suggested above Neumanns.

 

[Waxx]

that's not what I read in a review:


Let's not downplay what is a very competent speaker design with some outstanding qualities, not to mention visual design that will be at home in a modern apartment, unlike suggested above Neumanns.

That it's technical quiet good is not an discussion, we are a bit nitpicking here. But for that money we can do that i think.

Style is not my cup of tea (but that is subjective, so not relevant here). And i do actually know a few who live in an apartment with Neumann KH420's as speaker, one even has some KH750 subs with it... But if it fits your expectations, the better. It certainly does not fit mine, altough i can appreciate the effort they took to get here. It's just not finished for me, make that low distortion in a speaker that has a neutral FR and even dispertion and i'm in, even for 8K. But this is not that speaker.

 

[Lars Risbo]

I see some complains about the dispersion. The choice of going 2 way and not the conventional 2.5 way was very deliberate. This gives two distinct advantages: 1) the two woofers do load sharing right up to the xover to the tweeter which lowers the midrange distortion considerably, and 2) 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 ). Running the woofers in parallel gives of course a narrowing vertical pattern which seems to be the complaint here. However, we surmise that this may help mitigate the effect of the the floor and ceiling reflection since two woofers in parallel is a step towards a line array (they have a sin x/x type vertical patterns and are very narrow vertically.

i hope i explained the choice we made and I still think it was the right call and it is of course fair to disagree (especially after hearing it).

The vertical dispersion i mostly notice is from the AMT that narrows fast due to its long vertical dimension.

Anyway, the combined PIR is fairly nice.

I am not sure i understand the critique of the FR. Would be nice to have it even smoother but the passive filter would quickly blow up in complexity (see the EQ suggestion - each biquad would add two reactive components in the equivalent passive filter).

Finally, it should also be emphasised that this is a floor stander that has an F10 of 24Hz (the F328Be was at 40Hz) which is very rare in this size. It can play deep, loud and precise bass without a sub.

 

[Cote Dazur]

i hope i explained the choice we made and I still think it was the right call and it is of course fair to disagree (especially after hearing it).

We are seeing typical nitpicking, nothing out of the ordinary.
I have not heard this speaker, neither did 99% of people posting here.
I wish I did.
In the larger scheme of thing, the price will not be a barrier to the many that are demanding on speaker quality and can allow to spend what is required to get such a gem of a speaker.
Having you here explaining in details what was done and why is priceless, for everything else there is Mastercard.