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[Jeff Bankston]

Can someone post comb filtering images of these side by side horn configs to show comb filtering ? Crossover point is 1500 HZ 24DB LR active. Horns are not splayed. All horns are the same model. ^ ← horn symbol. Thank you.

 40404040    4 - 40 deg horns side by side butted against each other.
   ^^^^ 

 60606060    4 - 60 deg horns side by side butted against each other.
   ^^^^

 60404060    4 - 60 40 40 60 deg horns side by side butted against each other.
   ^^^^

 40604060    4 - 40 60 40 60 deg horns side by side butted against each other.
   ^^^^

[Dave Pluke]

Can someone post comb filtering images of these side by side horn configs to show comb filtering ? Crossover point is 1500 HZ 24DB LR active. Horns are not splayed. All horns are the same model. ^ ← horn symbol.

Pretty simple CAD task to draw adjacent triangles to get a rudimentary idea of where comb filtering will occur. But, it would be helpful to know the center-to-center distance between drivers and the model of waveguides/horns in question, as advertised dispersion angles are only at certain frequencies.

Dave

[Caleb Dueck]

Can someone post comb filtering images of these side by side horn configs to show comb filtering ? Crossover point is 1500 HZ 24DB LR active. Horns are not splayed. All horns are the same model. ^ ← horn symbol. Thank you.

 40404040    4 - 40 deg horns side by side butted against each other.
   ^^^^ 

 60606060    4 - 60 deg horns side by side butted against each other.
   ^^^^

 60404060    4 - 60 40 40 60 deg horns side by side butted against each other.
   ^^^^

 40604060    4 - 40 60 40 60 deg horns side by side butted against each other.
   ^^^^

Do you have EASE Focus?  It's free and can do this. 

[Jeff Bankston]

Do you have EASE Focus?  It's free and can do this.

No I dont and I'm still using Windows XP.

[Ivan Beaver]

Can someone post comb filtering images of these side by side horn configs to show comb filtering ? Crossover point is 1500 HZ 24DB LR active. Horns are not splayed. All horns are the same model. ^ ← horn symbol. Thank you.

 40404040    4 - 40 deg horns side by side butted against each other.
   ^^^^ 

 60606060    4 - 60 deg horns side by side butted against each other.
   ^^^^

 60404060    4 - 60 40 40 60 deg horns side by side butted against each other.
   ^^^^

 40604060    4 - 40 60 40 60 deg horns side by side butted against each other.
   ^^^^

It is not that simple.  How large are the horns, vs where the components are in them (the spacing of the components is what is key),

What freq are you looking for? THe interference can vary a lot with freq

 What is the cut angle of the cabinets.  Very often the horn wall angles are not the same as the cabinet walls  You may see a 60* horn with cabinet walls that are 15*.  The cabinet walls should be 1/2 of the rated pattern

You really need to state the specific models you are looking at, as the rated pattern may not be the actual pattern (in most case it is not).  It may be-give or take a bit.

[Jeff Bankston]

Pretty simple CAD task to draw adjacent triangles to get a rudimentary idea of where comb filtering will occur. But, it would be helpful to know the center-to-center distance between drivers and the model of waveguides/horns in question, as advertised dispersion angles are only at certain frequencies.

Dave

24" center to center. DDS CFD 2-60X Pro horns.  Radian 850PB 2" drivers.

http://usspeaker.com/dds%20cfd-2-60x%20pro-1.htm

http://usspeaker.com/radian%20850pb-1.htm

[Jeff Bankston]

It is not that simple.  How large are the horns, vs where the components are in them (the spacing of the components is what is key),

What freq are you looking for? THe interference can vary a lot with freq

 What is the cut angle of the cabinets.  Very often the horn wall angles are not the same as the cabinet walls  You may see a 60* horn with cabinet walls that are 15*.  The cabinet walls should be 1/2 of the rated pattern

You really need to state the specific models you are looking at, as the rated pattern may not be the actual pattern (in most case it is not).  It may be-give or take a bit.

24" center to center. DDS CFD 2-60X Pro horns.  Radian 850PB 2" drivers. Operating frequency 1500-16K. Cabinets are 24" square.

http://usspeaker.com/dds%20cfd-2-60x%20pro-1.htm

http://usspeaker.com/radian%20850pb-1.htm

[Scott Bolt]

23" center to center. DDS CFD 2-60X Pro horns.  Radian 850PB 2" drivers.

http://usspeaker.com/dds%20cfd-2-60x%20pro-1.htm

http://usspeaker.com/radian%20850pb-1.htm

The biggest comb filtering happens because of 2 speakers set one stage left and one stage right.  The angle the horns spread the sound mostly effects WHERE the comb filtering happens.

The REASON comb filtering happens is because of time delays between when the sound from one speaker hits a position to when the sound from the other speaker hits the same position.  If your speakers are right next to each other, it is of less consequence than when they are separated by 40 feet across a stage.

While the combing is frequency dependent (because different frequencies have different wave lengths) the most obvious filtering happens at lower frequencies.

In addition to the sound being generated at different distances from the listener, most rooms also have reflections within the room that not only arrive at different times, but are reflected out of phase as well.

For inside gigs, I don't think the horn splay is anywhere near the biggest problem to think about.  Outside?  I still think there are bigger issues to consider, but lots of people seem to think it is a big deal, so it is possible I am wrong .

[Jeff Bankston]

I was just asking if someone had the program that would show the differents  colors that show the hot spots of comb filtering

[David Sturzenbecher]

I was just asking if someone had the program that would show the differents  colors that show the hot spots of comb filtering

Anyone can use Meyer’s Maap, Danley Direct, EASE Focus, d&b soundscape, L Acosutics Soundvision, plus probably a have dozen more.  All those programs are available to you at the low low cost of one hour of your time to watch a 15 minute YouTube video and 45 minutes to play around with the horn patterns of your liking.  Plus, acoustical modeling opens up a whole new world of “ah ha’s”.

And if you are using windows XP on your daily driver computer, I pray you never log onto anything that has any sort or banking or credit card info

[Brian Jojade]

No I dont and I'm still using Windows XP.

Sill using XP and want to see a graphical drawing of how NOT to deploy speakers ever?  I'm not sure I understand the end game here..

[Ivan Beaver]

The biggest comb filtering happens because of 2 speakers set one stage left and one stage right.  The angle the horns spread the sound mostly effects WHERE the comb filtering happens.

The REASON comb filtering happens is because of time delays between when the sound from one speaker hits a position to when the sound from the other speaker hits the same position.  If your speakers are right next to each other, it is of less consequence than when they are separated by 40 feet across a stage.

While the combing is frequency dependent (because different frequencies have different wave lengths) the most obvious filtering happens at lower frequencies.

Not exactly. 

It is not the distance between the horns that is the issue, but rather the LISTENERS distance between them.

The greatest cancellation happens when the levels are the same between the devices.  If 1 device is a good distance away, then it's level will be lower, so the effect of the combfilter will be not as deep.

Also the further away, the lower the point at which the first notch occurs, and the closer together the notches will be.

Here is the math.  The first (lowest freq) will be 1/2 of the difference in arrival times (in terms of freq).  So a 1' difference in arrival time would be a notch around 565 Hz (give or take for elevation etc). 

And each subsequent notch will be at the rate or 565Hz.  So the next ones would be @1130hz, 1695Hz, 2260 etc.

While the lower notches can appear as holes in the response, the higher ones appear as a "dulling" of the sound, as if a little boost on the top end will fix it.  But it doesn't.  You can't fix time issues with eq.

Even a small offset of arrival times (as in small parts of an inch or a few mm) can make a noticeable difference.

[Ivan Beaver]

24" center to center. DDS CFD 2-60X Pro horns.  Radian 850PB 2" drivers. Operating frequency 1500-16K. Cabinets are 24" square.

http://usspeaker.com/dds%20cfd-2-60x%20pro-1.htm

http://usspeaker.com/radian%20850pb-1.htm

I just noticed that you said in the original post that the horns were not splayed.

The combfiltering will be different at different distances (horizontal) from the horns.  So "it depends" applies a lot here. 

Different seats will have have different notches based on distance, and different notches based on freq, that is dependent upon the actual pattern control of the horn at particular freq and how much each horn contributes to the overall energy at a particular freq.

So for the particular horns you referenced, (using the basic horn pattern loss formula)   freq=1,000,000/pattern in degrees/horn exit in inches 

You have a pattern loss freq of 877Hz in the 60* part of the pattern and 1500Hz in the 40* part of the horn.  So with your 1500Hz xover, you should be good in general terms of pattern control being what it says, but it also depends on the ACTUAL pattern of the horn.  That can vary a bit.

What you are asking for is a lot of data points for somebody (who has a good bit of time) to calculate, or a bunch of different screen captures to show the different notching at different freq vs different seats.

But suffice it to say, if you have those horns, sitting next to each other, all facing the same direction, you WILL have noticeable combfiltering that will shift as you move around.

[Scott Holtzman]

Sill using XP and want to see a graphical drawing of how NOT to deploy speakers ever?  I'm not sure I understand the end game here..

How are you guys possibly using XP?  The browsers have not been upgraded in so long you must be incredibly limited in the web sites you can access, how are you accessing this one?  It uses a cipher that is not supported in XP.

[Jeff Bankston]

How are you guys possibly using XP?  The browsers have not been upgraded in so long you must be incredibly limited in the web sites you can access, how are you accessing this one?  It uses a cipher that is not supported in XP.

Firefox still works for web surfing. But there are programs that will not download to xp anymore. I didnt like 7 , vista , and 8. I was thinking of getting a 10 pc. Now I hear there is 11. 11 must be really loud.

[Scott Holtzman]

Firefox still works for web surfing. But there are programs that will not download to xp anymore. I didnt like 7 , vista , and 8. I was thinking of getting a 10 pc. Now I hear there is 11. 11 must be really loud.

11 didn't really deserve a new version number.  It is a nice visual upgrade but if you are not using Microsoft's SSO universe (microsoft.net) or advanced features like hypervisors and sandboxing there is not much to see.  You also have to buy pro if you want a local login.  I am not quite sure how that works on airplanes yet I was not interested enough to load the developers release.


Windows 10 without a doubt is Microsoft's finest effort.  It brought a lot of new technology and security forward.  It's easy and visually reasonable.  I personally don't understand the the angst of end users and OS's, they blend into the background.  When I upgraded my wife's computer from 7 to 10 it took her a week until she said I though it changed quite a bit. 


90% of what we do is in browsers today anyway,  I love the profiles that let me take my browser experience from computer to phone to work computer to tablet to laptop seamlessly. 

[Russell Ault]

{...} I am not quite sure how that works on airplanes {...}

As a Microsoft-hosted-SSO naysayer I've never tried it, but I would ASSume offline login works similarly to "old-fashioned" Active Directory (i.e. credential caching).

-Russ

[Scott Bolt]

Not exactly. 

It is not the distance between the horns that is the issue, but rather the LISTENERS distance between them.

The greatest cancellation happens when the levels are the same between the devices.  If 1 device is a good distance away, then it's level will be lower, so the effect of the combfilter will be not as deep.

Also the further away, the lower the point at which the first notch occurs, and the closer together the notches will be.

Here is the math.  The first (lowest freq) will be 1/2 of the difference in arrival times (in terms of freq).  So a 1' difference in arrival time would be a notch around 565 Hz (give or take for elevation etc). 

And each subsequent notch will be at the rate or 565Hz.  So the next ones would be @1130hz, 1695Hz, 2260 etc.

While the lower notches can appear as holes in the response, the higher ones appear as a "dulling" of the sound, as if a little boost on the top end will fix it.  But it doesn't.  You can't fix time issues with eq.

Even a small offset of arrival times (as in small parts of an inch or a few mm) can make a noticeable difference.

Ivan is (of course) correct.  The actual distance that matters is the distance from each speaker to the listeners ears.  He is also quite correct that you can't "fix" time issues with eq (although many have tried).

Still, it has been my experience that pretty much any indoor venue (with some few exceptions) reflections  and room dynamics are going to be a much bigger problem than comb filtering.  The utility of putting tops over subs stage left and right has always won out in my book.  Sure, there are more sonically pure ways to deploy a simple PA system; however, they are mostly not worth the lost utility and ease of setup indoors due to limited possible layouts of speakers.

Outdoors .... different story altogether.

[Craig Hauber]

How are you guys possibly using XP?  The browsers have not been upgraded in so long you must be incredibly limited in the web sites you can access, how are you accessing this one?  It uses a cipher that is not supported in XP.

I know quite a few folks who's PC is still XP
-it just sits in the corner collecting dust while they use an android/apple tablets and their phones!

But seriously, XP is dead for anything requiring online use.
I have a dedicated older laptop I use for older serial-port managed devices with all their control software loaded on it.  It never sees the 'net but I wish modern windows was as simple and responsive as that machine feels!

[Paul Johnson]

NONE of my computers here will upgrade to Windows 11 - my i7 4000 series chips that I'm very happy with, performance wise are not acceptable - so Windows 10 should apparently be fine till 2025. I still have XP on a Panasonic tough book for a specific purpose and Firefox seems fine?

[Doug Fowler]

I know quite a few folks who's PC is still XP
-it just sits in the corner collecting dust while they use an android/apple tablets and their phones!

But seriously, XP is dead for anything requiring online use.
I have a dedicated older laptop I use for older serial-port managed devices with all their control software loaded on it.  It never sees the 'net but I wish modern windows was as simple and responsive as that machine feels!

And how many Server/SQL 2000 are out there humming away running whatever company app they were installed for?

If its not broke don't fix it.   

There may be a time of reckoning coming for the legacy VA ERM
system but it still works pretty well.  It's not "pretty" but it produces the desired results.

https://en.m.wikipedia.org/wiki/MUMPS

Built-in ISAM access.

[Russell Ault]

{...} If its not broke don't fix it. {...}

But that's just it: for most users* Windows XP (actually, anything older than Windows 8.1) is broken. Windows XP has many well-known, un-patched security vulnerabilities, and as of a few months ago Windows 7 now falls into the same category.

(*If you're a big enough company/government and you pay Microsoft enough money they probably will patch your old Windows versions, at least to some extent, but this doesn't apply to retail/OEM customers.)

-Russ

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