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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Tom Phillips. on February 04, 2014, 09:11:33 PM

Title: Distance Between speakers before Delay necersarry
Post by: Tom Phillips. on February 04, 2014, 09:11:33 PM
Hi,

Im after a few opinions as to how far back "delay" speakers need to be before it is necersarry to actually delay them in processing.

I am designing an installed system for a fitness club spin studio (indoor cycling) in a 10x10 meter room, which will have 3 or 4 rows of 8 bikes.

my plan was to have a second set of speakers halfway down the room to reduce the levels required coming from the foh and increase the vocal inteligebility in the back to rows.

The second set of speakrs will be 4 or 5 meters max from the foh, so at this distance is it necersarry to time delay the rear speakers, or will it not be noticable enought to justify the additional amplification/processing?

Appreciate any input.

Thanks,
Tom.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Jason Lavoie on February 06, 2014, 11:29:42 AM
Hi,

Im after a few opinions as to how far back "delay" speakers need to be before it is necersarry to actually delay them in processing.

I am designing an installed system for a fitness club spin studio (indoor cycling) in a 10x10 meter room, which will have 3 or 4 rows of 8 bikes.

my plan was to have a second set of speakers halfway down the room to reduce the levels required coming from the foh and increase the vocal inteligebility in the back to rows.

The second set of speakrs will be 4 or 5 meters max from the foh, so at this distance is it necersarry to time delay the rear speakers, or will it not be noticable enought to justify the additional amplification/processing?

Appreciate any input.

Thanks,
Tom.

at 4-5m difference you might hear it but nobody else will. Keep in mind that 5m along the wall means that someone in the middle of the room only has maybe a 2-3m difference in distance between the different speakers. that's a greater distance than what most of the class will have between left and right.

Unless you have good isolation between the zones, applying a delay to the fills will just make it worse for the people up front who will be hearing some of the fills.

Jason
Title: Re: Distance Between speakers before Delay necersarry
Post by: g'bye, Dick Rees on February 06, 2014, 11:39:39 AM
at 4-5m difference you might hear it but nobody else will. Keep in mind that 5m along the wall means that someone in the middle of the room only has maybe a 2-3m difference in distance between the different speakers. that's a greater distance than what most of the class will have between left and right.

Unless you have good isolation between the zones, applying a delay to the fills will just make it worse for the people up front who will be hearing some of the fills.

Jason

Yup.  I think the best way to do audio in such areas is a distributed system in the ceiling firing down.  SOS point source cabinets will have varying amounts of suck and success depending on the listening position, more suck than success, though.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Jonathan Kok on February 06, 2014, 01:28:51 PM
Yup.  I think the best way to do audio in such areas is a distributed system in the ceiling firing down.  SOS point source cabinets will have varying amounts of suck and success depending on the listening position, more suck than success, though.
Agreed. Unless there's a physical limitation preventing you from installing ceiling speakers, it'd definitely be the preferred method.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Tom Phillips. on February 06, 2014, 03:39:32 PM
Agreed. Unless there's a physical limitation preventing you from installing ceiling speakers, it'd definitely be the preferred method.

Yes, trying to avoid cutting holes in the ceiling tiles..

Plan was to use either Quest Hpi-110 or Hpi-8i boxes mounted horizontally on a yoke bracket from the ceiling. Both models have an asymmetrical horn (similar pattern to a nexo ps10 I believe)

Thanks for everyone's input, I hadn't even thought about the results that the delay would have on the people in the front being such a close gap...
Title: Re: Distance Between speakers before Delay necersarry
Post by: g'bye, Dick Rees on February 06, 2014, 03:43:05 PM
Yes, trying to avoid cutting holes in the ceiling tiles..

Plan was to use either Quest Hpi-110 or Hpi-8i boxes mounted horizontally on a yoke bracket from the ceiling. Both models have an asymmetrical horn (similar pattern to a nexo ps10 I believe)

Thanks for everyone's input, I hadn't even thought about the results that the delay would have on the people in the front being such a close gap...

You want ALL the listeners to be equi-distant from the sound source(s)...as much as possible.  You can use one or two speakers IF you have the ceiling height, but for that size room you'd more or less need a ceiling height in excess of 15' .
Title: Re: Distance Between speakers before Delay necersarry
Post by: Luke Geis on February 06, 2014, 04:59:51 PM
I have done a large amount of distributed systems over the years and there are a few rules to follow. JBL has a handbook from the 1950's that lines out distributed systems quite a bit. Basically it says if the speakers are within about 25' or the magical 4-5 meters, there is usually not enough distance for the listener to hear delay. The reason being is that the distance is just close enough that by the time you start to triangulate and use the Pythagorean theorem the delay time is rather small and or the inverse square law works to your advantage. It seems to be true in my experience. When you have the speakers rather close as you walk between them, one fades away as the other fades in and it seems as if you simply walking across one big speaker. There may be a very small or barely noticeable amount of delay if closer to the 25' mark, but it really does work.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Ivan Beaver on February 06, 2014, 07:07:12 PM
Hi,

Im after a few opinions as to how far back "delay" speakers need to be before it is necersarry to actually delay them in processing.

I am designing an installed system for a fitness club spin studio (indoor cycling) in a 10x10 meter room, which will have 3 or 4 rows of 8 bikes.

my plan was to have a second set of speakers halfway down the room to reduce the levels required coming from the foh and increase the vocal inteligebility in the back to rows.

The second set of speakrs will be 4 or 5 meters max from the foh, so at this distance is it necersarry to time delay the rear speakers, or will it not be noticable enought to justify the additional amplification/processing?

Appreciate any input.

Thanks,
Tom.
Maybe I am missing something-but as I "see" it why is there a FOH position?  Is there a stage?  or a focal point?

If not-then there may be better approaches-such as a distributed downfiring system.

How many delays you may or may not need depends on the height of the speakers and the coverage pattern of the particular loudspeakers.

There is more information needed before any "numbers" can be given.

Of course it also depends on what the "level of acceptance is".  I highly doubt people working out on bikes are going to be very concerned with the overall audio quality or imaging or localization.

I would probably more ticked off by the music selection---------
Title: Re: Distance Between speakers before Delay necersarry
Post by: Tom Phillips. on February 06, 2014, 07:54:00 PM
Maybe I am missing something-but as I "see" it why is there a FOH position?  Is there a stage?  or a focal point?

If not-then there may be better approaches-such as a distributed downfiring system.

How many delays you may or may not need depends on the height of the speakers and the coverage pattern of the particular loudspeakers.

There is more information needed before any "numbers" can be given.

Of course it also depends on what the "level of acceptance is".  I highly doubt people working out on bikes are going to be very concerned with the overall audio quality or imaging or localization.

I would probably more ticked off by the music selection---------

No Stage, but an instructer at the front of the room with headset mic.

Imaging is not a concern, but sound quality is.

The system needs to be able to comfortably go quite loud for late night classes.

My only reasoning for more than two speakers was just to keep levels reletively consistent front to back.

System is to include a sub or two, most likely these:
http://www.questaudio.com.au/product_details/product/Quest_HPI_12S_Ultra_Compact_Passive_Sub-Bass

Cheers.

Tom.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Ivan Beaver on February 06, 2014, 08:12:23 PM


Imaging is not a concern, but sound quality is.


Define "sound quality"?

In a situation like this "sound quality" can mean very different things.

Are you looking for a system to provide accurate sound-such as in studio monitor quality?  OR being able to simply hear the instructor clearly?

I find it hard to believe that people on bikes will be critically listening.

And if sound quality is important-then the fewer speakers you use the better the quality will be-no matter what model speaker.
Title: Re: Distance Between speakers before Delay necersarry
Post by: Brad Weber on February 08, 2014, 09:25:53 AM
The system needs to be able to comfortably go quite loud for late night classes.
Why would late night classes need to be louder than any others?  Given many of the other similar past discussions here, might you encounter issues with the resulting sound levels at neighboring businesses or residences?
 
I'd personally look at some of the recessed ceiling mount products from companies like Tannoy, QSC, Atlas Sound and so forth.  I understand you want to avoid cutting ceiling tiles but you wouldn't hang the Quest Hpi boxes you noted from the suspended ceiling grid, they'd have to be mounted to the actual building structure above so you'd be cutting tiles anyways.