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Author Topic: Mono sum + HPF  (Read 8603 times)

luis Markson

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Mono sum + HPF
« on: April 19, 2011, 03:24:59 am »

For a retail environments,  I am assuming that in ceiling speakers are summed to mono?

I'm looking at a particular powered system that requires a HPF @ 80Hz. Without delving into expensive DSP what cost effective units existed for mono summing that include a HPF?
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Chris Carpenter

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Re: Mono sum + HPF
« Reply #1 on: April 19, 2011, 03:50:25 am »

For a retail environments,  I am assuming that in ceiling speakers are summed to mono?

I'm looking at a particular powered system that requires a HPF @ 80Hz. Without delving into expensive DSP what cost effective units existed for mono summing that include a HPF?
For a retail environment, your typically looking at a 70v system. Quite a few places run these with integrated mixer/amplifier units that can take a line level signal. They usually do the summing on their own. HPF shouldn't really be necessary at retail volume levels.

What particular powered system, and for what application?
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luis Markson

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Re: Mono sum + HPF
« Reply #2 on: April 19, 2011, 04:33:24 am »

For a retail environment, your typically looking at a 70v system. Quite a few places run these with integrated mixer/amplifier units that can take a line level signal. They usually do the summing on their own. HPF shouldn't really be necessary at retail volume levels.

What particular powered system, and for what application?

I'm looking at this:

http://www.atprofessional.com.au/products/mk100.php

The space is a one room rectangle aprox' 10m x 5m

Subtle, ambient music
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Brad Weber

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Re: Mono sum + HPF
« Reply #3 on: April 19, 2011, 07:51:00 am »

For a retail environments,  I am assuming that in ceiling speakers are summed to mono?
Typically, although some retail applications will try to create stereo zones.

I'm looking at a particular powered system that requires a HPF @ 80Hz. Without delving into expensive DSP what cost effective units existed for mono summing that include a HPF?
So you're looking at the MK100A version and having to deal with an IEC power cord at each speaker location?  The manufacturer doesn't seem to offer information online beyond the basic product page data so I'm not sure where it is identified that the speaker needs an 80Hz high pass filter, but if it does then it seems that a 70V system might make sense as even cheaper transformers could probably handle that at ambient music levels without transformer low frequency saturation or response being a concern.
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luis Markson

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Re: Mono sum + HPF
« Reply #4 on: April 19, 2011, 08:17:41 am »

Typically, although some retail applications will try to create stereo zones.
So you're looking at the MK100A version and having to deal with an IEC power cord at each speaker location?  The manufacturer doesn't seem to offer information online beyond the basic product page data so I'm not sure where it is identified that the speaker needs an 80Hz high pass filter, but if it does then it seems that a 70V system might make sense as even cheaper transformers could probably handle that at ambient music levels without transformer low frequency saturation or response being a concern.

I'm trying to figure out if I can get away with 1 unit. The filter was recommended via a phone conversation.
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Brad Weber

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Re: Mono sum + HPF
« Reply #5 on: April 19, 2011, 10:52:11 am »

I'm trying to figure out if I can get away with 1 unit. The filter was recommended via a phone conversation.
How high will the speaker be mounted?  And do they provide any directivity information beyond the very nebulous 'high frequency dispersion' below 8kHz of 120 +/-10 degrees?  I'm a little curious as to how they get such wide dispersion from a simple single 4" full range driver.  Just for some comparison, an Atlas Sound FA114 in a FA97-4 enclosure is almost hemispherical at 1kHz and has a -6dB coverage of 135 degrees at 2kHz, about 100 degrees at 4kHz and around 50 degrees at 8kHz.  And the -6dB pattern for a Bose DS 40F is similar with about 120 degrees at 1kHz, 150 degrees at 2kHz, 100 degrees at 4kHz and 50 degrees at 8kHz.
 
And don't forget that with wide dispersion speakers the distance a listener is from the speaker can vary significantly within the -6dB coverage pattern.  Say the ceiling is 10' high and the listeners are standing, so a person directly under the speaker would be around 5' from it while someone 60 degrees off axis would be about 10' away from the speaker and thus more like 10-12dB down in level relative to the listener on axis.  Without any overlap from other speakers to compensate that could be a factor.
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luis Markson

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Re: Mono sum + HPF
« Reply #6 on: April 19, 2011, 07:25:17 pm »

How high will the speaker be mounted?  And do they provide any directivity information beyond the very nebulous 'high frequency dispersion' below 8kHz of 120 +/-10 degrees?  I'm a little curious as to how they get such wide dispersion from a simple single 4" full range driver.  Just for some comparison, an Atlas Sound FA114 in a FA97-4 enclosure is almost hemispherical at 1kHz and has a -6dB coverage of 135 degrees at 2kHz, about 100 degrees at 4kHz and around 50 degrees at 8kHz.  And the -6dB pattern for a Bose DS 40F is similar with about 120 degrees at 1kHz, 150 degrees at 2kHz, 100 degrees at 4kHz and 50 degrees at 8kHz.
 
And don't forget that with wide dispersion speakers the distance a listener is from the speaker can vary significantly within the -6dB coverage pattern.  Say the ceiling is 10' high and the listeners are standing, so a person directly under the speaker would be around 5' from it while someone 60 degrees off axis would be about 10' away from the speaker and thus more like 10-12dB down in level relative to the listener on axis.  Without any overlap from other speakers to compensate that could be a factor.

I have more detailed specs on a printed brochure, I'll pull them out tonight...

I'm not sure of the placement yet, I'm looking for reasources to help determine that.

The ceiling height is about 8'
« Last Edit: April 19, 2011, 07:32:58 pm by luis Markson »
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luis Markson

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Re: Mono sum + HPF
« Reply #7 on: April 19, 2011, 08:54:20 pm »

I have more detailed specs on a printed brochure, I'll pull them out tonight...

I'm not sure of the placement yet, I'm looking for reasources to help determine that.

The ceiling height is about 8'

Who are the main players in the constant voltage, in ceiling install market? Currently I am aware of Bose, QSC, Martin and Atlas...
« Last Edit: April 19, 2011, 11:10:38 pm by luis Markson »
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Brad Weber

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Re: Mono sum + HPF
« Reply #8 on: April 19, 2011, 10:07:19 pm »

Who are the main players in the constant voltage, in ceiling install market? Currently I am aware of Base, QSC, Martin and Atlas...
Also Tannoy, TOA, JBL, Soundtube, Lowell and I'm sure I'm missing some others.
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Chris Carpenter

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Re: Mono sum + HPF
« Reply #9 on: April 19, 2011, 10:13:43 pm »

Also Tannoy, TOA, JBL, Soundtube, Lowell and I'm sure I'm missing some others.
Ive been seeing more and more Bogen gear.
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ProSoundWeb Community

Re: Mono sum + HPF
« Reply #9 on: April 19, 2011, 10:13:43 pm »


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