Humble Statement

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Wow, what a project! I really love the look of the Martin Coltrane and this is almost a spot on replica as far as looks go. I also think this may be the first project Tony has published that uses a parallel crossover. I'd love to build one of these, but I feel like the woodworking would be over my head and the cost of the drivers alone would push my budget to uncomfortable levels. Who knows though! I'd love to hear others comments on this. Any experience with the Accuton T6-90 midrange Tony uses?

An externally hosted image should be here but it was not working when we last tested it.


Humble Statement
 
Tony continues to outdo himself.

I haven't seen a lot of DIY projects with the Accuton drivers - I think people are balking at the cost; only one driver tested by Zaph so far:

"Accuton C23-6 ($225) - Very expensive ceramic dome tweeter. Slightly ragged response and related energy storage issue at 4kHz. Mild top octave droop. Excellent 2nd order HD. Exceptional tall order HD above 3Khz, but high 3rd order HD below. If you can fix the response curve in the crossover, this is generally a good tweeter. There are better in this group however, and for less money."
 
Zaph writes: high 3rd order below..

but still the C23 measures as good as or better than all the other drivers. C23 seems like the best performer of the bunch so in some way one could say the price is justified in contrast to the other drivers that are more costly but has worse performance.


/Peter
 
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m0tion said:

I'm really just interested in hearing people's opinions on this speaker in general.


My personal opinion is that they are not very nice looking. I have the utmost respect for Tony's work, but these do not appeal to me at all.
Well built, certainly.

He references the Andromeda, with the idea that these will be a worthy heir as a no compromise design. I've never been a big fan of the Wilson Audio "Cylon Centurion" style speaker but I think, given the driver choices, the Andromeda has this one beat. His own measurements (for the Andromeda) show a fuller bottom end.
 
Hello,

regarding the looks of the "C 173N-T6-90": the front is not quite to my taste either, but the back certainly has some seriously "sexy" high-tech-appeal ... :cool: : nice photo of side and backside

I am considering to buy this driver for its (relatively) high efficiency and the very stiff yet well-dampened cone.

Somewhat irritating though are the measurements on the "Statement" website and the curve presented with the distortion-diagrams in this PDF.
There seems to be some resonance-phenomenon around 1 kHz that can not be "detected" in the normal frequency-plot (due to excessive smoothing I'd suppose..).

Of course, if my assumptions are correct so far, this must not necessarily mean a significant degradation in sound-quality. But at the price in question - and in the context of those ceramic domes - even such a "minor" imperfection seems difficult to accept to me ...


Regards,

Bernd
 
I'm really just interested in hearing people's opinions on this speaker in general.
I often exchange mails with Tony and listened to a few of its designs and I feel convenient to say that he favours the homogeneity of the different fr ranges (what he names "oneness") and also the most natural midrange presentation; The underhung VC and others specs ( notably its large SD) of the T6-90 helps in this matter but didn't mate perfectly the Utopia Be which is mostly a top octave than a low octave tweeter.
IMHO, an interesting thing to notice is the use of these accuton ceramic drivers which give at the same time a very uncolored but very balanced sound if correctly used in the speaker design. This caracter is also present in the Soup (all accuton drivers) when I compare it to my Modulus speakers (paper bass and mid). I would be currious to hear if the Statement is as homogeneous than his previous designs using 2.5-way series/parallel filters.;)
 
There seems to be some resonance-phenomenon around 1 kHz that can not be "detected" in the normal frequency-plot (due to excessive smoothing I'd suppose..).
Of course, if my assumptions are correct so far, this must not necessarily mean a significant degradation in sound-quality.
Firstly: Be sure Tony perfectly knows his matter and could suppress this emphasis with a noch or whatever other technic if it gaves a sound degradation.
Secondly: +/- 2db around 1Khz and more of a dip than a peak and no related distortion at these fr on the graph...;)
 
Unrfortunately you can not surpress non linear distortion with a notch filter or any other linear compensation.

I suspect there are some resonant behaviour in the spider that casues a slight increase in output and distortion. Still 0.3% THD at 100-105dB is respectable.

Second: +/-2dB in such a small range is more than necessary and not acceptable in a top grade speaker IMHO.

He mentions something about the shape of the internals of the midrange enclosure and that most of the rear energy is killed. Well the irregularities are of such small dimension that they hardly have an effect at all for the midrange. Mineral/glas wool would be a better material do treat this energy.

Of course I don't know the origin of these midrange ripples but it come from the inside or the outside of the box for sure. Hmm, the baffles looks like they are very thick.. wonder if the inside is chamfered..? Otherwise problems may show up from mounting the driver in a "tunnel" which can casue distortiond and possibly also deviation from a flat frequency response.


Very nice work though and I'm sure it performs very well.



/Peter
 
I really don't see where you guess a problem.
You say 0.3% THD at 100/105db is respectable...I would say it's uncommon with non horned drivers!
And where is the problem with +/-2db on a small fr range right before uppermid?
Personally, if I had a doubt with this design it would be in the field of the off-axis energy in the uppermid because cutting a 145cm2 SD near 2Khz isn't quite ideal. With such a SD, nondirectional piston range begins close to 800Hz.

About the inner shape of the mid enclosure, sure such small bumps and valleys have less than an effect but the global shape has no // walls and this helps reducing standing waves.

Just my 2 cents.;)
 
Well the problem might be that the driver has increased distortion around 1k and that indicates something is going on. Yes the driver is a good one but hey, let's strive for perfection okay? ;)

There are some drivers that perform equally good or better in part of the range, even non horn loaded drivers.

Wether the increase in distortion is a problem or not is hard to say of course without an in depth investigation of the driver. However if the distortion is of a type that is not increasing gradually but instead suddenly shows up, then the audibility might be worse..and such distortion is also often plauged with higher order harmonics.


The problem with +/-2dB ripple in a small range.. well it indicates once again that something is going on that shouldn't be there. It's just to much of a deviation from the raw respons of the driver indicating (likely) stored energy and/or difraction not dealth with sufficiently.

The enclosure will more or less behave as there is a back wall. Standing waves does not dissapear just because the shape is altered from a cube. ;) A standard internal shape where the reflection is damped with something more effective than sheep wool would likely produce better results.


/Peter
 
Well the problem might be that the driver has increased distortion around 1k and that indicates something is going on.
I don't see any increased THD around 1Khz on the rare plots on the net, only one huge breakup K2 near 5.7Khz where the two ears transform it into two reduced bumps, even no K3.
Yes the driver is a good one but hey, let's strive for perfection okay?
I don't know of any perfect driver except perhaps in heaven if God is an audiophile addict, do you?
There are some drivers that perform equally good or better in part of the range, even non horn loaded drivers.
Yes some floppy drivers that smooth the upper mid; up to 800-900hz I'm not sure at all they are on par with this one.
+/-2dB ripple in a small range.. well it indicates once again that something is going on that shouldn't be there. It's just to much of a deviation from the raw respons of the driver
The raw driver (IEC baffle?) DOES show this ripple; whatever it's due to, I won't take much more care on this because of the very small level of THD and a low level of energy storage that can be seen on the waterfall plot.
The enclosure will more or less behave as there is a back wall.
A rounded one...this helps...no rear wall at all doesn't much more help because of the huge impedance difference between inner air area plan and exterior.
Standing waves does not dissapear just because the shape is altered from a cube.
They are smoothed on a larger fr range.
A standard internal shape where the reflection is damped with something more effective than sheep wool would likely produce better results.
My point of view on this matter is: killing/avoiding standing waves before applying less dampening material which will then act more linearly without killing too much dynamics. But I agree that this applies more on bass drivers than mid drivers.;)
 
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