Radiant Acoustics Clarity 66 Speaker Review

[eliash]

Okay, understood.

Staying analog IMO is nostalgia without any added value, however, with additional complications which could be relatively easy corrected with proper DSP. I am using a Waxwing phono preamp and full digital signal flow - works and sound great!

Interesting solution, thanks!

 

[eliash]

Eliash, I have a pair of small active Dynaudio's BM5A II, rear ported, that were repaired and brought back to life a couple a weeks ago after sitting dormant for about 8 years! Although they are a "monitor" type speaker they are fairly rich sounding in the low end, although this can be adjusted with switches on the back, They have their limitations (in a bigger room), but i was very surprised just how enjoyable they are to listen to and how they transparent they are, much better than i remember them being.

What intrigues me about the 66 is the relative size of them for the output they produce, I've been thinking about getting larger speakers for my the living room, but having lived with large-ish JBLs and NHT speakers, a larger speakers tend to dominate the room, if i can get a "pint in a half pint pot" regarding size, naturalness, accurate timbre and fairly life like dynamics of larger speaker it's something id like to investigate.

I can tell you one thing about cabinet size and weight:
Vibration causes roughness and this is associated to lightweight, poor cabinet construction, its internal bracing and stands, all play a big role.
Everybody considers 100ps of jitter from a DAC as awful, but 0.1mm of mechanical cabinet vibration causes about 300ns of jitter (easily calculated by speed of sound).
There is an old japanese paper analysing human ears' sensivity to jitter. 300ns are the lower limit of cognition, if I remember correct.
Especially tower speakers like the Radiant or my Dynaudios with high mounted bass/voice drivers (high mass) cause a significant lever for cabinet movement. Did you ever wonder why Wilson's speaker sound so good?

 

[Purité Audio]

I have never wondered why Wilson speakers sound ‘good’!
Keith

 

[Everett T]

.Did you ever wonder why Wilson's speaker sound so good?

Are you talking about Wilson Audio speakers and if so, which ones? Their flagship speaker(s) are, IMHO, audio engineering disasters.

 

[eliash]

WATT/Puppies from ~25y ago. A friend and neighbor had them, sounded great, much less roughness compared to my Dynos...the rest is your judgement...

 

[DonH56]

Why not just apply some digital PEQ to tame your room modes? Much easier than modifying a ported loudspeaker.

Note EQ will work to reduce a peak, but often does not help (and may make things worse) trying to fix a null. A null caused by signal cancellation is not amenable to EQ; you will simply increase the wasted power. If the null is due to cancellation from reflections, i.e. A - B, then trying to increase the level by EQ simply increases power such as C * (A - B) and the result is no change in the relative amplitude of the node. If 1 - 1 = 0 from a null, then 10 - 10 = 0 as well.

 

[Space is the place]

Eliash, I'm guessing you mean by jitter cabinet colouration? Reading a few reviews i have read that some of the Dynaudio cabinets can have resonances.
Surely this isn't the case with the 66's? They are double the weight of most speakers from other manufacturers that size and if Mr Risbo can design a driver so low it distortion the cabinet perhaps is an easier proposition?

I think the lowest cabinet colouration i've heard on the speakers I've had, was perhaps on the Event Opals (a bit like a two way Genelec, but on steroids!).
I've not heard and Wilson speakers so can't really comment on them, Keith, have you had a pair?
My reservation about trying the 66's is can two 6 inch drivers bring the same energy and dynamics a larger speaker can?

 

[markstein]

Everybody considers 100ps of jitter from a DAC as awful, but 0.1mm of mechanical cabinet vibration causes about 300ns of jitter (easily calculated by speed of sound).
There is an old japanese paper analysing human ears' sensivity to jitter. 300ns are the lower limit of cognition, if I remember correct.

Any sources, any evidence?

And: How do you convert a mechanical displacement of 0,1mm into 300ns of jitter?

 

[markstein]

Note EQ will work to reduce a peak, but often does not help (and may make things worse) trying to fix a null. A null caused by signal cancellation is not amenable to EQ; you will simply increase the wasted power. If the null is due to cancellation from reflections, i.e. A - B, then trying to increase the level by EQ simply increases power such as C * (A - B) and the result is no change in the relative amplitude of the node. If 1 - 1 = 0 from a null, then 10 - 10 = 0 as well.

Correct, a null caused by reflections (look at excess group delay) should not be equalized. Changing the speaker reflex port does not get rid of a null either ;-)

 

[eliash]

Any sources, any evidence?

...and random jitter is probably harder to detect than rather periodic as caused by music playback...

And: How do you convert a mechanical displacement of 0,1mm into 300ns of jitter?

Simple,
consider yourself in front of a speaker baffle which moves backward and forward caused by vibration. In other words the listening distance changes.
Now consider how long it takes until the sound reaches your ear. This is determined by the speed of sound (340m/s).
Consider e.g. 0.1mm distance change, so the time needed to bridge that changed distance is 0.1mm / 340m/s = 294ns
Depending on the speaker construction, voice and HF drivers are modulated accordingly by the heavy bass membrane and voice coil momentum.

One reason, why I would not use a soft speaker stand nor flexing speaker racks...

 

[markstein]

View attachment 551580
...and random jitter is probably harder to detect than rather periodic as caused by music playback...

Simple,
consider yourself in front of a speaker baffle which moves backward and forward caused by vibration. In other words the listening distance changes.
Now consider how long it takes until the sound reaches your ear. This is determined by the speed of sound (340m/s).
Consider e.g. 0.1mm distance change, so the time needed to bridge that changed distance is 0.1mm / 340m/s = 294ns
Depending on the speaker construction, voice and HF drivers are modulated accordingly by the heavy bass membrane and voice coil momentum.

One reason, why I would not use a soft speaker stand nor flexing speaker racks...

This "jitter" should be measureable and show as an increase in HD and IMD, no?

 

[eliash]

Theory says so, ask the manufacturers for numbers.
At least I can hear an improvement by using rigid stands, like spikes on large steel plates or direct (via glued-on soft copper coins) on floating cast plaster floor (can't go down to the concrete floor layer due to heating pipes).
Anyway, soft stand on floating parquet is horrible for my ears...

 

[YouDontHaveEnoughBass]

Is this with sighted or blind comparisons?
“In blind [listening] tests the problem went-away.” - Floyd E. Toole, C.M.

 

[eliash]

...often listen with closed eyes...

 

[Purité Audio]

Obviously the only way to truly compare is to use two sets of identical loudspeakers one directly coupled one isolated, unsighted/level matched almost impossible in real life.
You can measure with a four plane accelerometer the amount of structural vibration transmitted to the floor, a laboratory isolation equipment manufacturer did exactly that here some years ago and the structural transmission was negligible.
Keith

 

[Mart68]

Consider e.g. 0.1mm distance change, so the time needed to bridge that changed distance is 0.1mm / 340m/s = 294ns

But your head is not moving at all? In fact it will move more than that just from breathing even if you try your hardest to remain totally still.

0.1mm is high anyway, if there is any movement it would be a fraction of that unless speaker cab is made of cardboard or something.

 

[eliash]

But your head is not moving at all? In fact it will move more than that just from breathing even if you try your hardest to remain totally still.

0.1mm is high anyway, if there is any movement it would be a fraction of that unless speaker cab is made of cardboard or something.

Of course my head is moving, fortunately, but fortunately not at speed of my speakers membranes. So we talk about different things here...the speaker excitation is of course the question. I tried to quantify that, but not reliably possible with my instrumentation. Anyway fingernail probing showed significant baffle moverment at the top edge of the enclosure. This is obviously due to cabinet movement, not so much cabinet deformation in this area.

Also we are not talking about the effects of acoustical energy fed to the floor and its effects, but cabinet movement.

 

[Mart68]

Of course my head is moving, fortunately, but fortunately not at speed of my speakers membranes. So we talk about different things here...the speaker excitation is of course the question. I tried to quantify that, but not reliably possible with my instrumentation. Anyway fingernail probing showed significant baffle moverment at the top edge of the enclosure. This is obviously due to cabinet movement, not so much cabinet deformation in this area.

Also we are not talking about the effects of acoustical energy fed to the floor and its effects, but cabinet movement.

Try putting a glass of water atop the speaker see how much vibration is conducted to the water, or balance a coin on top and see if it falls. Depends on the speaker but usually nothing will happen. Not saying there will be zero movement of the speaker cab due to driver motion, but it should be infinitesimal and the effect not even remotely audible.

 

[Coltr@ne]

Sum the MMS values of the drivers and mount them in a structure with 1000x the mass; the issue is negligible.

 

[markstein]

Theory says so, ask the manufacturers for numbers.
At least I can hear an improvement by using rigid stands, like spikes on large steel plates or direct (via glued-on soft copper coins) on floating cast plaster floor (can't go down to the concrete floor layer due to heating pipes).
Anyway, soft stand on floating parquet is horrible for my ears...

I think you are mixing things up.

The effects you describe (vibration of loudspeaker enclosure) will be visible as resonances in the spinorama (the enclosure is excited at specific resonance frequencies and emits sounds). Theory says resonances are distracting and shall be minimized, correct.

Edit: A vibrating enclosure might also produce Doppler distortion./Edit
Such effects may or may not be also visible in HD and IMD graphs (somebody more knowledgeable please comment).

I would not use the term "jitter" to describe this phenomenon, and I think your calculation is nonsense. Please excuse