Radiant Acoustics Clarity 66 Speaker Review

[Sokel]

To me that reads like those speakers would be comparable if you added a subwoofer to the KH150.

Getting good linearity and low distorsion in the midrange and in the treble is not that expensive, that the KH150 and the Clarity 66 compete there isn't surprising. What costs money is bass. You need stronger motors, larger enclosures, bigger drivers...

Agreed, IF subwoofers were prioritizing low distortion instead of the usual output vs extension vs size.
A lot of them are not even competing with smaller speakers in terms of distortion down low at comparable levels.

The 10 subwoofer thread shows lots about it.

 

[kharan]

Agreed, IF subwoofers were prioritizing low distortion instead of the usual output vs extension vs size.
A lot of them are not even competing with smaller speakers in terms of distortion down low at comparable levels.

The 10 subwoofer thread shows lots about it.

Add two KH 805 II and we're in the same price bracket as the Radiant.

 

[dfuller]

That process doesn't generate any distortion results. You have to measure distortion using a different module. Then, you can use yet another module to make it anechoic.

For curiosity's sake, do you have that module? I recall you trying anechoic once and not bothering. It would be at least somewhat interesting to me to see what would happen taking the same data with and without that module...

 

[Salt]

If I remember correctly, as by @SigbergAudio mentioned , an anechoic chamber is not very helpful in bass frequency.

 

[dfuller]

If I remember correctly, as by @SigbergAudio mentioned , an anechoic chamber is not very helpful in bass frequency.

To be clear this is a Klippel software module, not hardware AFAIK.

 

[SigbergAudio]

If I remember correctly, as by @SigbergAudio mentioned , an anechoic chamber is not very helpful in bass frequency.

It depends on the size. I use the Seas chamber, it's accurate down to around 70hz, and below that the deviation is known, so in reality it's useful all the way down. The most accurate way to do bass measurement is probably ground plane measurement outdoors. But even then you don't really know exactly what happens in a room at any given placement.

 

[amirm]

For curiosity's sake, do you have that module? I recall you trying anechoic once and not bothering. It would be at least somewhat interesting to me to see what would happen taking the same data with and without that module...

I do. I found the process error prone. I forget the details but that made me concerned about positing results that may not be accurate.

Are you asking to use it for the Clarity 66? If so, sure, i can try. But I am not ready to run it for future reviews.

 

[amirm]

It depends on the size. I use the Seas chamber, it's accurate down to around 70hz, and below that the deviation is known, so in reality it's useful all the way down.

They have calibrations but those tend to be specific to exact speaker/mic location. Should the speaker change, have ports separate from drivers and such, their calibration suffers. In other words, if there is modal response, by definition then it is speaker and mic location sensitive.

 

[dfuller]

I do. I found the process error prone.

That makes sense, if it was tossing out screwy results.

Are you asking to use it for the Clarity 66? If so, sure, i can try. But I am not ready to run it for future reviews.

Nah, no need.

 

[b73i57dc3f]

similar distortion performance above 100Hz for both THD and MTD

Looking at the ASR THD measurements (same measurement conditions), relative THD of the Clarity 66 is about 5-10 dB (eyeballing) lower throughout that range. The MTD comparison also shows differences of ~5 dB over wide ranges. Typically, it takes a significant change in output level to bring about the same effect. Given that, I really wouldn't call that similar. In my book, they're similar only in the range of 40-50 Hz, where the KH 150 has help from its port, while the Clarity 66 doesn't (due to its port tuning frequency being lower).
Theory tells us that doubling the number of woofers can either achieve half an octave deeper extension, or +6 dB higher output. I think what we're seeing here is close enough to the former below ~50 Hz, and the Clarity 66's significantly lower THD above ~50 Hz suggests something akin to the latter (which would also further reinforce that the Neumann and Purifi woofers perform fairly similar). Maximum SPL would then depend on whether the Clarity 66 is asked to play deep or not. With a subwoofer, the Clarity 66 should be able to play significantly louder than the KH 150 (also with a subwoofer). Otherwise, it would depend on program material, with the Clarity 66 being able to play either deeper or louder, but not both at the same time.

 

[SigbergAudio]

They have calibrations but those tend to be specific to exact speaker/mic location. Should the speaker change, have ports separate from drivers and such, their calibration suffers. In other words, if there is modal response, by definition then it is speaker and mic location sensitive.

There's a slight modal effect, but that's easy to negate since I know the response of the speaker is even in the bass. But in addition to that it shows a lower SPL level than the Klippel NFS from around 50-60hz and down to 20hz. At 20hz it's 4-5dB lower.

But yes, you'd need to know both the chamber and the speakers.

 

[Lars Risbo]

I did the deep dive bass distortion measurement (someone posted it early in thread) and it shows less distortion than the two NFS data points we have (albeit, Erin’s are close and there is unit to unit variation etc). There is pronounced distortion dip right at the port tuning frequency where the woofers don’t move much and the port output most of the sound. This was done using a 200V polarised mic quite close and position for equal mix of port and woofers. The analysis used a super slow exponential sine sweep which helps suppress noise and separate harmonics from very deep down in frequency. we used a large gym as well.

It’s a very good point to compare speakers at the same SPL at the bass frequency eg 30 or 50Hz. many speakers roll off the bass (you pay dearly for bass extension in terms of box size and sensitivity )

Edit: acknowledging that Erin’s NFS HD measurment is only marginally higher than my measurement (96dB)

 

[Lars Risbo]

copy pasted :

 

[Curvature]

Looking at the ASR THD measurements (same measurement conditions), relative THD of the Clarity 66 is about 5-10 dB (eyeballing) lower throughout that range. The MTD comparison also shows differences of ~5 dB over wide ranges. Typically, it takes a significant change in output level to bring about the same effect. Given that, I really wouldn't call that similar. In my book, they're similar only in the range of 40-50 Hz, where the KH 150 has help from its port, while the Clarity 66 doesn't (due to its port tuning frequency being lower).
Theory tells us that doubling the number of woofers can either achieve half an octave deeper extension, or +6 dB higher output. I think what we're seeing here is close enough to the former below ~50 Hz, and the Clarity 66's significantly lower THD above ~50 Hz suggests something akin to the latter (which would also further reinforce that the Neumann and Purifi woofers perform fairly similar). Maximum SPL would then depend on whether the Clarity 66 is asked to play deep or not. With a subwoofer, the Clarity 66 should be able to play significantly louder than the KH 150 (also with a subwoofer). Otherwise, it would depend on program material, with the Clarity 66 being able to play either deeper or louder, but not both at the same time.

For clarity, here's the difference graph below vs. the KH150:

 

[Jonazkur]

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.

I have the same problem in my diy Audiohorn/Purifi speaker at 130-140hz. Its hard to get rid of.

 

[gnarly]

Agreed, IF subwoofers were prioritizing low distortion instead of the usual output vs extension vs size.

Exactly.
And to prioritize low distortion, the sub designers/marketplace would be forced to accept it simply takes more size.
Which of course runs afoul of room-uh-aesthetics....the Achilles heel of home audio......or more like the Achilles LEGS lol

Imo, Radiant did a nice job for the size imo. That said, i agree with @kharan, alot of speakers with a decent sub would make for an easy, prob less expensive matchup.

Personally, I view harmonic distortion as a simple measure of "how hard is the speaker working"...and true for subs thru tweeters.
So for my DIYs, I merely try to overbuild in terms of SPL capability, which automatically lowers distortion at common listening levels.

Take one of my subs for example, a double 18" in clamshell opposed arrangement. Ported and tuned to 30Hz. (Breaks aesthetics rules)
This distortion plot looks good, but nothing super great....until you notice its at nearly 120dB @2m.....add 6dB to get its
distortion at 125.6 dB.

I don't even bother with 86, & 96 dB distortion measurements anymore,
...knowing at those levels and usually up to say 116dB, distortion will be dirt low from overbuilding..
.....which is boatloads cheaper for me than buying pinnacle-type home audio products.