The review offers a good amount of technical info as food for thought. I'm about finished reading it and want to think about it a bit.

I did hear them at HE2007, they were playing drum music at a VERY LOUD level! I was sitting front row and could see the woofers moving what looked like .5" if not more. The fellow there would not answer any of my questions, just looked at me with his mouth shut tight, LOL! And I was wearing a business suit, ... odd. I think my first question was are they linear phase, perhaps he didn't want to give out any technical info.

The music was not to my taste. I could see visually that the speakers were not even symmetrically placed. Placement was obviously sloppy as were many other speakers. They obviously had dynamics, but it was difficult to judge much else. I don't trust listening at shows, really have to have them at home and spend time with them to draw any valid conclusions.

Pete B.

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Have you seen/heard these at HE2007, Elk .. others?
http://www.cepro.com/article/cabasse_set_to_debut_la_sphere_speakers/K5

As set up by the manufacturer in Michael Fremer's listening room for our review, there were some problems -- see www.stereophile.com/standloudspeakers/608cab/index5.html -- though the speaker does show enormous promise.

I am still trying to get my head around the fact that the presentation mentioned is the US dealer premier when Cabasse's PR guy told us back in the spring that the speaker was available from more than 5 US dealers and thus qualified for a review. I am thinking it will be a while before we publish any more Cabasse reviews.

John Atkinson
Editor, Stereophile

Hi John,

Interesting review, I'll try to comment when I have some time. I wonder if they've done any modifications so that they can claim that this is at least a revision to the previously available units? Curious as to how many they've sold.

Pete B.

Regarding the initial question of what are some of the issues with digital filters: This covers some issues such as Dither, Quantization Noise, Limit cycles, etc:
http://www.rane.com/note157.html

Pete B.

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Pete, a nice easy to read primer. A good start. Thanks.

Do you have a citation to an article that deals more with phase shift and comparisons to analog circuits?

I'm not sure of exactly what you're looking for. You mentioned a few things previously about phase shift in 6 dB/oct XO's and now digital vs. analog. Is all of this with regard to speaker design or analog vs. digital in general?

The main thing with digital, especially in the early years, is that you have to band limit the signal in order to avoid aliasing. This is called an anti-aliasing filter and in 1X sampled systems it is very close to the audio band. However, we can do a lot better now, by first oversampling the incoming data, 4X allows us to put the filter 4X higher in frequency obviously, then do most of the antialias filtering digitally with linear phase filters, then downsample to 1X. This has no disadvantages and it is a way to get better quality even within the constraints of the 1X format.

Not sure if this answers your question. The very steep analog filter for a 1X system does cause phase shift in the audio band, however I doubt that it is audible. More audible is probably the fact that no matter how steep, there can be times when it is not steep enough. Higher sampling rates and steep digital filters should make this a non-issue and also solve the phase shift problem within the audio band.

Pete B.

They look like alien eye balls from a Si-Fi movie.

A digital DIY design, nice work:
http://www.diyaudio.com/forums/showthread.php?postid=1586573#post1586573

Looks mighty fine also:
http://img.villagephotos.com/p/2005-7/1050288/tism173.jpg
Pete B.