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Author Topic: what in the world are they thinking ?  (Read 23864 times)

Tom Young

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what in the world are they thinking ?
« on: May 27, 2011, 09:51:16 am »

I am hunting down some speakers for an unusual installation project and checked the K-Array website. I have heard their column speakers a few times and think they're contenders for/in that market.

But the leading headline on their website really disturbs me. See:

http://www.k-array.net/

and the top NEWS story: "A Beautiful Front-fill".

In this news item a sound guy has chosen a fairly long column speaker as a *front fill* speaker in larger theaters.

specs: http://www.k-array.net/downloads/karray/datasheet/KR200S_data_B.pdf

So just to be clear: there is a need to cover across the front seats and the sound dude choose a speaker, which when laid on its side, has 7-degrees horizontal coverage directly on axis to the center of the column. How does this cover more than (say) 3-5 seats with HF and upper MF energy ?

OK, OK. Egregious errors by marketing folks are nothing new in the pro audio market/press and elsewhere. We all know that.

But think about what this does to the basic understanding of electroaocustics for the novice who reads this stuff.

And (equally troubling).... how did the sound dude not notice the lack of HF coverage across the front seats ?

This is not the first time I have seen a column speaker deployed in such a flawed manner. But I find it startling, disturbing and disconcerting to see this on the front page of a pro audio speaker manufacturer's website.

end of rant
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Tom Young
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Frederik RosenkjŠr

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Re: what in the world are they thinking ?
« Reply #1 on: May 27, 2011, 10:14:51 am »

I don't understand the problem?

As far as I know they consist of a lot of small drivers all reproducing the entire frequency spectrum. Wouldn't that mean that the horizontal coverage (horizontal when lying down) is not 7 degrees measured from the center but out from each end of the stick? (and when laying them end-to-end the "middle field" where it acts as a cylindrical radiator (array length and driver distance permitting) is just extended).
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Tom Young

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Re: what in the world are they thinking ?
« Reply #2 on: May 27, 2011, 10:21:20 am »

I don't understand the problem?

As far as I know they consist of a lot of small drivers all reproducing the entire frequency spectrum. Wouldn't that mean that the horizontal coverage (horizontal when lying down) is not 7 degrees measured from the center but out from each end of the stick? (and when laying them end-to-end the "middle field" where it acts as a cylindrical radiator (array length and driver distance permitting) is just extended).

No.

Look at the polars for this speaker or any other columnar speaker (Bose MA12, for one). Take the vertical polars and rotate them 90-degrees. This is what the column spoeaker does in the horizontal axis when laid on its side (well..... without some side-effects of the stage lip and/or floor).

Take this a step further and sign up for MAP On-line at Meyer Sound. Build a column array with MM-4 drivers. Map the coverage. Rotate the array. Check coverage at the various fractional-octave points.

Another interesting experiment is to mount a column speaker on its side (horizontally) on a stand and rotate it (or walk across the coverage area) and listen to what occurs ..... especially at HF's.

Cylindrical wavefronts are part, or almost, a theoretical myth (as is the "point source") and may only be achieved through mirroring with the floor (and ceiling ? ... I forget).

If it *was* possible to use column speakers for front fill, under-balcony fill, etc. I can assure you that many of us would do so.
« Last Edit: May 27, 2011, 12:40:44 pm by Tom Young »
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Tom Young
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Mac Kerr

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Re: what in the world are they thinking ?
« Reply #3 on: May 27, 2011, 10:30:54 am »

I don't understand the problem?

As far as I know they consist of a lot of small drivers all reproducing the entire frequency spectrum. Wouldn't that mean that the horizontal coverage (horizontal when lying down) is not 7 degrees measured from the center but out from each end of the stick? (and when laying them end-to-end the "middle field" where it acts as a cylindrical radiator (array length and driver distance permitting) is just extended).

This might work if the entire audience width was covered with speakers placed end to end, creating a single line the width of the audience. For single speakers, or even that long line, the HF is focussed toward the center of the speaker. I was amazed by this phenomena while listening to an LDS L-800 column speaker that was used as a proscenium mounted vocal system in a theater. In the front row the end seat was looking right into the bottom driver of the column. When you sat down in that seat you could distinctly hear all the high end go away as you sat down, despite the fact that you were staring right into a working ribbon driver. the high end really came back on when you stood up enough to be staring at the 3rd ribbon up in the column.

Mac
« Last Edit: May 27, 2011, 10:49:31 am by Mac Kerr »
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Matt Errend

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Re: what in the world are they thinking ?
« Reply #4 on: May 27, 2011, 07:32:24 pm »

I don't understand the problem?

As far as I know they consist of a lot of small drivers all reproducing the entire frequency spectrum. Wouldn't that mean that the horizontal coverage (horizontal when lying down) is not 7 degrees measured from the center but out from each end of the stick? (and when laying them end-to-end the "middle field" where it acts as a cylindrical radiator (array length and driver distance permitting) is just extended).

No.

Look at the polars for this speaker or any other columnar speaker (Bose MA12, for one). Take the vertical polars and rotate them 90-degrees. This is what the column spoeaker does in the horizontal axis when laid on its side (well..... without some side-effects of the stage lip and/or floor).

Take this a step further and sign up for MAP On-line at Meyer Sound. Build a column array with MM-4 drivers. Map the coverage. Rotate the array. Check coverage at the various fractional-octave points.

Another interesting experiment is to mount a column speaker on its side (horizontally) on a stand and rotate it (or walk across the coverage area) and listen to what occurs ..... especially at HF's.

Cylindrical wavefronts are part, or almost, a theoretical myth (as is the "point source") and may only be achieved through mirroring with the floor (and ceiling ? ... I forget).

If it *was* possible to use column speakers for front fill, under-balcony fill, etc. I can assure you that many of us would do so.

Have you considered that they might be changing the way the DSP is functioning when it is placed horizontally?
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Tom Young

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Re: what in the world are they thinking ?
« Reply #5 on: May 27, 2011, 09:31:56 pm »

No.

Look at the polars for this speaker or any other columnar speaker (Bose MA12, for one). Take the vertical polars and rotate them 90-degrees. This is what the column spoeaker does in the horizontal axis when laid on its side (well..... without some side-effects of the stage lip and/or floor).

Take this a step further and sign up for MAP On-line at Meyer Sound. Build a column array with MM-4 drivers. Map the coverage. Rotate the array. Check coverage at the various fractional-octave points.

Another interesting experiment is to mount a column speaker on its side (horizontally) on a stand and rotate it (or walk across the coverage area) and listen to what occurs ..... especially at HF's.

Cylindrical wavefronts are part, or almost, a theoretical myth (as is the "point source") and may only be achieved through mirroring with the floor (and ceiling ? ... I forget).

If it *was* possible to use column speakers for front fill, under-balcony fill, etc. I can assure you that many of us would do so.


Have you considered that they might be changing the way the DSP is functioning when it is placed horizontally?

Have you considered looking at the article and then the specs for this system ?

There is DSP. However there is no indication that it is employed to vary the coverage pattern. The coverage pattern is stated as 7V x 100H. And the published polars support this. Period.

Take a look at any of the digitally steerable column speakers out there and see if you can find any reference to placing them on their sides for any application let alone something like this. Actually, you could make good use of this (narrow horizontal, wide vertical)  in a tall atrium with a narrow horizontal field. But that is not what we're talking about here.

To answer your question:  I did research what this system does prior to posting about this.
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Tom Young
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Robert Lunceford

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Re: what in the world are they thinking ?
« Reply #6 on: May 28, 2011, 02:46:22 am »

Down-fill?
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Tim McCulloch

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Re: what in the world are they thinking ?
« Reply #7 on: May 28, 2011, 03:17:57 am »

Wow.  Just wow.  Nothing about this give me warm, fuzzy feelings.
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Ales Dravinec

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Re: what in the world are they thinking ?
« Reply #8 on: May 28, 2011, 03:19:36 am »

Down-fall !

Here, I corrected it for you :)

Once and for all, there is no such thing as cylindrical wave front. (for crying out loud).

w/r
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Keith Broughton

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Re: what in the world are they thinking ?
« Reply #9 on: May 28, 2011, 10:10:37 am »

Here, I corrected it for you :)

LOL! Made my day :)
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ProSoundWeb Community

Re: what in the world are they thinking ?
┬ź Reply #9 on: May 28, 2011, 10:10:37 am ┬╗


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