[CIAudio]

Here are measurements of a very popular speaker from a Stereophile review. You can see that the frequency response is all over the place except directly on-axis, and this is with 1/10th octave smoothing!

[dB Cooper]

Name names!

[dB Cooper]

As development continues, we have reduced distortion in the low frequencies by eliminating the passive radiator and using a custom aperiodic tuning.

The aperiodic tuning removes non-linearities caused by the air-spring in the enclosure, while maintaining damping to the lowest frequencies. This approach yields performance similar to a transmission line but with greatly reduced cabinet size, and the smooth 2nd order roll-off makes it very friendly to a wide variety of room sizes.

The dimensions of the finished speaker are 15”h x 9”w x 10”d and weight is 30 lbs each

Due to this improved cabinet design, the speaker will now be called the a3

I am a fan of aperiodic tuning and have been ever since my Dynaco A-25's way back when. Don't know why it hasn't been more widely used. You forgot to mention that it also produces a very linear impedance curve that gets the best out of amps. Hope to hear this design sometime. Did I mention that it also supports detailed and tight bass?

[Clio09]

Duke LeJuene of AudioKinesis designs speakers for best off axis response. I used to own his Jazz Modules which used the TAD 1102 driver and a 1" neodynium tweeter mounted in a round wave guide. Best box speakers I have ever owned. Definitely interested in hearing these speakers.

[CIAudio]

lenses for the aperiodic vents were machined today 

[jtwrace]

Dan Wiggins
https://www.youtube.com/watch?v=Q-lCnzd0ggs

[abd1]

Sorry if I missed this somewhere, but any sensitivity ratings?

[CIAudio]

Efficiency will be around 85~86db/2.83v.
Hard to get much more with a small, wide bandwidth loudspeaker.

We choose “system efficiency” over “speaker efficiency”.
For example, a pair of 96db efficient speakers being driven by a 3.5 watt SET amp will have a maximum output 99db and draw about 250 watts.
A pair of 85db efficient speakers powered by our C•100S will have a max output of 105db, with wider bandwidth, better dynamics, and draw only 240 watts.

[CIAudio]

Having extremely well-behaved drivers allows for much simpler crossover design 

[CIAudio]

Below are some quick measurements from a pre-production prototype a3.




Frequency response:
Purple= On axis (0 degrees)
Green= 15 degrees off axis
Orange= 30 degrees off axis
Red= 45 degrees off axis

Light Blue=Phase
Black=THD

It's rare to have flat/consistent response to beyond 20k from 0-45 degrees off axis.
Notice how all 4 FR measurements are near identical, this provides amazing imaging with a much larger sweet spot.

[Paulie]

That's a pretty impressive graph!  Man I wish I could hear these things.  Will you be sending any out for reviews?

[CIAudio]

That's a pretty impressive graph!  Man I wish I could hear these things.  Will you be sending any out for reviews?

I'm sure we will get some reviews, but just trying to get the first 30 pair into production for now.
We will have 15 pair of Light Maple finish baffle with CI gray cabinet, and 15 pair of Dark Mahogany baffle with black cabinet.

I've also got prototypes of matching speaker stands being made. They are constructed of 17 layer baltic birch with heavy machined aluminum top plate, base is a sandwich of baltic birch and 1/8" aluminum.
Stands will be available in Maple and Mahogany finishes. Adjustable aluminum ball spikes are included.

December is still the target, but it always seems to take me a little longer 

[Russell Dawkins]

Here are measurements of a very popular speaker from a Stereophile review. You can see that the frequency response is all over the place except directly on-axis, and this is with 1/10th octave smoothing!

Of course you can't see what the response is on axis because the on-axis response is always normalized in Stereophile's measurements. All we see is pretty nasty off-axis curves.
Earlier in the thread you speak as if the matching off axis response of your design allows for speaker placement with less or no toe-in. I would have thought the advantage of good off-axis performance (and what is shown is extraordinarily good) would be that this enabled aiming the speakers inward, thus reducing wall bounce generated by speakers firing forward but close to the side walls, as I so often see in photos of listening rooms. If the 15, 30 and 45º curves are not level matched it looks like there is no potential to exploit the BBC technique of crossing the axes in front of the listener to widen the sweet spot, since this depends on falling levels off axis, not to speak of requiring high quality curves like yours, off axis.

Big fan of aperiodic boxes, not so much of 1st order crossovers.

[CIAudio]

The waveguide controls directivity, limiting dispersion to 145 degrees. This makes the 1st reflection further away than with conventional designs. You can still toe-in if placement is near a wall but is not required to have good imaging.

[poseidonsvoice]

Below are some quick measurements from a pre-production prototype a3.




Frequency response:
Purple= On axis (0 degrees)
Green= 15 degrees off axis
Orange= 30 degrees off axis
Red= 45 degrees off axis

Light Blue=Phase
Black=THD

It's rare to have flat/consistent response to beyond 20k from 0-45 degrees off axis.
Notice how all 4 FR measurements are near identical, this provides amazing imaging with a much larger sweet spot.

I realize you are trying to fit an FR measurement, along with a phase measurement and THD measurement all on one vertical axis. The vertical axis is now poor in resolution as such and is a 100dB scale. It appears on your horizontal scale that the smoothing is ~?1 octave? Is that right, I am squinting a bit!?

Is there a way you can just post the FR measurements with as little as smoothing as possible to visualize the differences between the 3-4 curves? Do you have polar plot or contour plot measurements?

Thanks,
Anand.

[CIAudio]

These are just quick measurements of a prototype under development to give you an idea of their off axis performance.

As you mentioned, the scale is to show many measurements on a single graph.

We will have a variety of performance measurements once we finalize and test actual production units.

[CIAudio]

The final design has now been completed.
After testing various driver alignments and configurations, the passive radiator wins out over aperiodic.
I’m still a fan of aperiodic designs, but the tuned radiator works best in our design.

All parts are now in production... custom capacitors being made by Clarity Cap, Jantzen inductors coming from Poland, and cabinets being fabricated here in California.
If things stay on track, we’ll be shipping in late December!

[Nordkapp]

I'm in the market for a high performance bookshelf. Do you have an approximate price yet?

[Russell Dawkins]

Below are some quick measurements from a pre-production prototype a3.




Frequency response:
Purple= On axis (0 degrees)
Green= 15 degrees off axis
Orange= 30 degrees off axis
Red= 45 degrees off axis

Light Blue=Phase
Black=THD

It's rare to have flat/consistent response to beyond 20k from 0-45 degrees off axis.
Notice how all 4 FR measurements are near identical, this provides amazing imaging with a much larger sweet spot.

I've never seen a chart even remotely close to this for off-axis HF behaviour—and you appear to be using a conical waveguide for the tweeter which isn't all that unusual. I admit to being puzzled. What are other designers missing?

[richidoo]

Phase response is awesome! First order xo and time-aligned drivers. This is how you get truly natural tone, something few people have ever heard, the opposite of today's "hifi" speakers. Depending on the price, these should be very well received.
Congrats Dusty!