[gtommers]

If you look at this description of the Sierra-1 crossover:

http://www.ascendacoustics.com/pages/products/speakers/SRM1/srm1tech.html

It says:

"OPPIX stands for Optimized Paradromic Phase Integrated X-Over (crossover). This sophisticated variable slope crossover precisely aligns the acoustic phase response of multiple transducers at the exact point where the response of one transducer crosses over to another, with reference to a specific point in space. This precise alignment allows the transducers to mimic a single point source radiator, allowing for symmetrical dispersion even with an asymmetrical transducer layout while maintaining a linear frequency response and greatly reducing off-axis phase and response anomalies. It also avoids the undesirable frequency response anomalies commonly found with even the best coaxial drivers."

I have no idea what this means but I'm curious what Dennis Murphy thinks of this approach, and how it relates to his crossover designs.

[Big Red Machine]

I'm not sure what it means, but I've got to get me one of those!

[R Swerdlow]

If you run that through an online translator and select translation from Marketing Buzzword Technobabble to English, you'll get something like this:

Long Version:
This crossover was designed by taking into account the frequency response and phase of the individual drivers in order to obtain an overall smooth frequency response and minimize out-of-phase interactions between drivers, on- and off-axis, within an octave or two of the crossover point.

Short Version:
We try to design our crossovers so they perform well.

Dennis might very well say, this should be standard industry practice, but often isn't.

[jsalk]

David is a great speaker designer and fine gentleman.  My comments should not be viewed as a criticism of him in any way - period.

That said, this is one of my pet peeves.  I learned long ago that if you are not able to write something in a cogent, straight-forward fashion that allows people to understand it, you are not communicating.  You are either wasting your time, bullying or purposely trying to create fog.

I have dealt with engineers all my life and many seem to have one trait in common.  They try to impress you with their knowledge by talking over your head.  They are not trying to communicate.  They are trying to establish superiority.  (I was fortunate in that I almost always understood what they were saying - a source of great frustration for them).

I see this technique employed all the time on audio forums.  The poster explains something in such a complicated fashion that no one is able to question his expertise on the subject matter.  His post is not designed to illuminate the situation at hand, but rather to establish himself as superior to all the other poor souls who are obviously clueless (which tends to be most other people reading the thread).  This kind of reminds me of the bully in the school yard.  The only difference is that powerful words are used in place of a powerful right hook.

OK...back to reality...

- Jim

[srb]

My electro-mechanical audio transducers are paradromic in relation to my audio/video component support structure.
 
Steve

[JLM]

The Sierra has been well reviewed.  I too wish simplier (less technical/less flowery) language would be used in audio.

I own the original Ascend Acoustics speaker, the smaller, uglier CBM-1, another 2 - way.  I love them.  Very musical, yet detailed.  And they image like champs.  Very high on apparent content value.  The standard black/rough vinyl finish is best for dorm rooms, audiophiles on very tight budgets, or "straights" who can't imagine spending what might make us puke.  I recommend these speakers often.

[ricardojoa]

Seriously, if you try to read it carefully, you should be able to understand or at least get an idea of what that is. Those are common wording, you shouldnt need a dictionary.

[DMurphy]

Seriously, if you try to read it carefully, you should be able to understand or at least get an idea of what that is. Those are common wording, you shouldnt need a dictionary.

Well, I just spent a half hour trying to explain what was being stated (and why it's nothing new) but I lost it when I tried to copy a quote from my blog.  Maybe I'll try and recreate it tomorrow.  But I think this is just a very opaque way of saying the Sierra crossover compensates for the different acoustic centers of the tweeter and woofer by introducing electrical lag in the tweeter's output relative to the woofer, and does this by changing the acoustic slope of either the woofer or tweeter.  Every crossover designer working with a conventional vertical baffle and an even order Linkwitz-Riley crossover knows that this compensation is necessary.   Jeff Bagby wrote an excellent white paper on these "mixed order crossovers" many years ago.  It should be noted, however, that even though the tweeter and woofer will technically be be in phase after one of the slopes has been properly adjusted, , they won't be at the same point in the music.  For a 4th order crossover, the tweeter and woofer will be exactly one cycle apart.  And this compensation will not eliminate nulls in the speaker's output when you move off axis vertically.  So the power repsonse in the room--the sum of all the direct and indirect sound arriving at the listening point--will not be flat.    Now maybe the Sierra crossover is more innovative than this.  If so, then the creator needs to explain, in English, what has really been done.

[jsalk]

Seriously, if you try to read it carefully, you should be able to understand or at least get an idea of what that is. Those are common wording, you shouldn't need a dictionary.

Absolutely true.

My point, however, is that for it be be effective communication, this extra effort required to "decode" the message should not be necessary.  While it may be technically accurate, it is obviously (as evidenced by the original post) not very effective at communicating its content. That being the case, you have to wonder why it was written in the first place.

I should point out that I have worked on quite a few projects explaining technical things to non-technical audiences.  So I come by my point of view honestly.  Want to know the ins and outs of an HP vector impedance meter?  Need to effectively communicate technical medical issues to a group of doctors?  I've done those types of things in the past and it is all about effective communications.  If you don't make it effortless to understand, no one will.  You have to "code" the message so your audience does not have to work to "decode" it.  It's that simple.

Usually things like this are written to impress, not to communicate.

- Jim 

[AlexG]

Keep it simple Watson! "Simple is Better" when explaining to the world 

[Mudslide]

It is to my ardent aspiration to circumvent his oratorical proclivities and to make feasible his indulgences in such frolicsome proclamatory recreation.  However, the magnitude of his phraseology is too copious for my diminutive comprehension.

 

Parsimony, dude.

 

[ricardojoa]

Can't blame those who don't pay attention on what they read!

[ctviggen]

If you look at this description of the Sierra-1 crossover:

http://www.ascendacoustics.com/pages/products/speakers/SRM1/srm1tech.html

It says:

"OPPIX stands for Optimized Paradromic Phase Integrated X-Over (crossover). This sophisticated variable slope crossover precisely aligns the acoustic phase response of multiple transducers at the exact point where the response of one transducer crosses over to another, with reference to a specific point in space. This precise alignment allows the transducers to mimic a single point source radiator, allowing for symmetrical dispersion even with an asymmetrical transducer layout while maintaining a linear frequency response and greatly reducing off-axis phase and response anomalies. It also avoids the undesirable frequency response anomalies commonly found with even the best coaxial drivers."

And what happens if you don't listen to the speakers at that single point in space?  Are all the purported benefits maintained?

[billmcc]

I am not sure why the description of the Sierra x-over is worded as it is but I have dealt with Dave F. personally and he is a great person. I know no one is knocking him personally in any way but thought I would give my opinion . I have had my Sierras for close to 1 1/2 years and have enjoyed them throughly.

I had originally ordered my LCR Sierras in Piano Black. When I got them I noticed that the finish on the R&L were not as smooth as the center. I called Ascend and they apologized that the R&L Sierras were B stock sent by mistake. It was not a problem at all and they would ship A stock right away then I could return the B stock ones. Well it turns out that the Piano Black cabinents were back ordered and might not be available for several months. Again no big deal as the B stock ones sounded great and Dave could not have been anymore apologetic.

So a month or so goes by and Dave contacts me telling me that the Sierras would soon be available in Dark Cherry and Expresso. He said he would gladly upgrade the Piano Black B stock and the A stock center for no charge shipping included . I jumped on that offer and patiently waited for the new finishes to arrive. The cabinents came in and Dave contacted me several times asking when I would like the Dark Cherry Sierras shipped. What impressed me most about this is that Dave contacted me twice without having to contact him and say hey where are my speakers. He also took back my A stock Piano Black center with no upgrade charge.

So I guess I am posting this to show what excellent service Ascend offers. As much as I have enjoyed the Sierras I have the upgrade bug and it looks like Salk speakers are in my future . I have been lucky to deal with great speaker companies such as Dynaudio (excellent service), Ascend and now possibly Salk. Build quality and of course SQ are big factors for me when looking for speakers. But service is also very important to me as well. From what I have read the service from Jim is excellent as well and all his speakers are getting rave reviews. I'm hooked .

Bill

[DMurphy]

Thanks.  I don't think anyone is questioning Ascend's service, expertise, or sound quality.  Just the description of whatever crossover topology is being used. 

[jsalk]

I, too, have the highest regard for Dave.  That is why, in my first post, I took pains to indicate that I was in no way criticizing him personally.  He is a quality individual and a credit to this industry.  And he builds darn fine speakers to boot!

- Jim

[billmcc]

Dennis and Jim,

I didn't think anyone in the thread talked negatively about Dave including yourselves. I just thought it would be good to convey how great Ascend's service is (in my situation) and how far Dave will go to make a customer happy .

Bill

[Nuance]

It is to my ardent aspiration to circumvent his oratorical proclivities and to make feasible his indulgences in such frolicsome proclamatory recreation.  However, the magnitude of his phraseology is too copious for my diminutive comprehension.

 

Parsimony, dude.

 

LMAO!