AudioCircle
Industry Circles => GR Research => Topic started by: harley52 on 10 Apr 2014, 10:27 pm
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I came across this article about a year ago, just before I purchased my speakers. It's the reason I ultimately decided on them......a sweetspot that can be adjusted for size :thumb:. Thought someone may find it helpful for truly understanding the proper way of setting up waveguide speakers and how versatile they are in set up.
www.libinst.com/PublicArticle/Setup%20of%20wg%20Speakers.pdf
I don't know why the link won't work from here but, it works fine when I try it elsewhere. Sorry gang.
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http://libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf (http://libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf)
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I came across this article about a year ago, just before I purchased my speakers. It's the reason I ultimately decided on them......a sweetspot that can be adjusted for size :thumb:. Thought someone may find it helpful for truly understanding the proper way of setting up waveguide speakers and how versatile they are in set up.
www.libinst.com/PublicArticle/Setup%20of%20wg%20Speakers.pdf
I don't know why the link won't work from here but, it works fine when I try it elsewhere. Sorry gang.
Why don't you post this topic in the Enclosures circle instead of here?
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While it may not seem the best fit on the surface, it could prove serendipitous. I had never heard this, in fact had no understanding of waveguides and their function/use, and I think at least one of the new designs Danny is working on has a waveguide so this thread may prove timely.
Mike
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AKLegal,
Thanks, that works better.
Rajacat,
Not trying to be hardheaded but, what does the set up of WG speakers have to do with enclosures. Educate me please. :green:
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I think that "enclosures" means box speakers in general. I thought that that your topic would be more suited for that circle. I don't believe that GR offers any waveguide speakers at this time.
BTW WG speakers are usually set up cross firing at 45 degrees to an area just in front of the listening position. This heavy toe-in creates a large sweet spot enhanced by the controlled directivity.
ed. I just read the updated link. :duh:
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I think that "enclosures" means box speakers in general. I thought that that your topic would be more suited for that circle. I don't believe that GR offers any waveguide speakers at this time.
BTW WG speakers are usually set up cross firing at 45 degrees to an area just in front of the listening position. This heavy toe-in creates a large sweet spot enhanced by the controlled directivity.
ed. I just read the updated link. :duh:
Harley, great point re Waveguides. Responder above must have missed class when the "V" series were discussed. Ummmmm, coax drivers are "waveguides". My Super Vs are toed 9" on a 8' listening field. As OBs, they are out 8 1/2' from front wall ! Danny would applaud this. With a 13' axial length the stage, depth, and imaging are incredible. As important, the Dynamics are vastly improved and shared equally across a 7' couch. Most profound are wide field rendering of often constricted classical stage. Here, I'll put the Vs up against most anything and don't even get me going on bass. Thanks for the link Harley, it's a read most should benefit from. Simple but profound! Here's hoping Danny can mix it up with Bob Smith, waveguides' best friend.
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Guys, in reality it really doesn't work like they illustrate.
A wave guide design is said to have a controlled dispersion much like illustrated. However, that is only true within a limited frequency range that is effected by the horn. As frequency decreases the pattern becomes omni directional just like any other speaker.
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Guys, in reality it really doesn't work like they illustrate.
A wave guide design is said to have a controlled dispersion much like illustrated. However, that is only true within a limited frequency range that is effected by the horn. As frequency decreases the pattern becomes omni directional just like any other speaker.
So if you set a waveguide speaker up with extreme toe to get the smoothest response out of the horn do you mess up the response of the other drivers?
Mike
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So if you set a waveguide speaker up with extreme toe to get the smoothest response out of the horn do you mess up the response of the other drivers?
Mike
It doesn't really change anything in the lower ranges at all. And the on axis response is usually just as smooth as the off axis with the horn loaded driver. In fact the extreme toe in only minimizes the side wall reflections in the top octave.
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Another problem that is always overlooked by these guys is that the biggest reflection point in the room is typically not the side walls. It's the ceiling. And you want just as smooth and even response in vertical off axis response as well as the horizontal off axis response.
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Horizontal SEOS15
(http://i288.photobucket.com/albums/ll164/bwaslo/SEOS15Horiz.png)
Verticle SEOS15
(http://i288.photobucket.com/albums/ll164/bwaslo/SEOS15Vert.png)
http://www.diyaudio.com/forums/group-buys/166312-waveguides-horns-60.html
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That one has pretty good vertical off axis too. The low crossover point or low extension of the wave guide really helps. What really hurts is the added center to center distance in most designs. The stretched out graph on that one is so big that it makes it look a bit artificially good in a way. It measures okay though. 4kHz to 5.5kHz drops 5db though. And from between 15kHz and 20kHz there isn't anything even in the on axis. And that's where your spacial cues come from. And what is happening below 1kHz? Where is the output down low? Is this a tweeter in a wave guide only?
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Here is a comparative that will put a little meat on this.
Here are two speakers. One uses an 8" woofer and a tweeter in a large wave guide. The other uses a 6.5" woofer and a Neo tweeter. Compare horizontal and vertical off axis measurements.
Speaker 1: Horizontal
(http://gr-research.com/pics/behhorizontal.jpg)
Vertical
(http://gr-research.com/pics/behvertical.jpg)
Speaker 2: Horizontal
(http://gr-research.com/pics/Neo2Xhor.jpg)
Vertical
(http://gr-research.com/pics/Neo2Xvert.jpg)
Now imagine towing the speakers in 30 degrees (green line on both speakers). Are they really different? Did the wave guide change the dispersion in a significant way? Not really...
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One would expect similar responses, but that's not the point. Harley's intent was to exploit the waveguides directive energy such that multiple listeners enjoy a similar sound field. Though toeing works in this regard with any speaker, doing so mitigates the lopsided drowning affect listeners, to your left and right, suffer while looking down the barrel of a waveguide. Sitting side by side has it's merits !
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That one has pretty good vertical off axis too. The low crossover point or low extension of the wave guide really helps. What really hurts is the added center to center distance in most designs. The stretched out graph on that one is so big that it makes it look a bit artificially good in a way. It measures okay though. 4kHz to 5.5kHz drops 5db though. And from between 15kHz and 20kHz there isn't anything even in the on axis. And that's where your spacial cues come from. And what is happening below 1kHz? Where is the output down low? Is this a tweeter in a wave guide only?
Those measurements are for just the waveguide and compression driver. No crossover, no smoothing, driven via 100uF series cap. The high freq. rolloff could probably be mitigated by using a beryllium compression driver. In reality most who have heard this setup don't notice the rolloff. A supertweeter could help too. The waveguide was never intended for full range use. Most will use a quality 15" pro midwoofer such as the Acoustic Elegance TD15M. You can get full range with this combo in a ported box. If you choose a sealed enclosure, a sub or a swarm of subs is required.
There are also 18" and 24" versions available which will lower the crossover point to the woofer for more of a point source feel.
(http://www.diysoundgroup.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/s/e/seos_15front.jpg)
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Those measurements are for just the waveguide and compression driver. No crossover, no smoothing, driven via 100uF series cap. The high freq. rolloff could probably be mitigated by using a beryllium compression driver. In reality most who have heard this setup don't notice the rolloff. A supertweeter could help too. The waveguide was never intended for full range use. Most will use a quality 15" pro midwoofer such as the Acoustic Elegance TD15M. You can get full range with this combo in a ported box. If you choose a sealed enclosure, a sub or a swarm of subs is required.
There are also 18" and 24" versions available which will lower the crossover point to the woofer for more of a point source feel.
(http://www.diysoundgroup.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/s/e/seos_15front.jpg)
Could you tell us where/who we could find above, implemented. ? Really off topic, sorry.
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Here are some links.
http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here
http://www.diyaudio.com/forums/group-buys/166312-waveguides-horns-60.html
http://www.diysoundgroup.com/forum/
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One would expect similar responses, but that's not the point. Harley's intent was to exploit the waveguides directive energy such that multiple listeners enjoy a similar sound field. Though toeing works in this regard with any speaker, doing so mitigates the lopsided drowning affect listeners, to your left and right, suffer while looking down the barrel of a waveguide. Sitting side by side has it's merits !
Yep, I get it. Works well, but only in the upper ranges where the wave guide is handling the output. In ranges below 800Hz or so they behave much like any other speaker.
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Those measurements are for just the waveguide and compression driver. No crossover, no smoothing, driven via 100uF series cap. The high freq. rolloff could probably be mitigated by using a beryllium compression driver. In reality most who have heard this setup don't notice the rolloff. A supertweeter could help too. The waveguide was never intended for full range use. Most will use a quality 15" pro midwoofer such as the Acoustic Elegance TD15M. You can get full range with this combo in a ported box. If you choose a sealed enclosure, a sub or a swarm of subs is required.
There are also 18" and 24" versions available which will lower the crossover point to the woofer for more of a point source feel.
That's what I thought.
Actually the network can pull down the lower range making a flat response out of it with no drop off in the highs at all.
Super tweeters are actually quite tricky. They can easily cancel on axis response and cause bigger holes in the response then without them. They work well facing to the rear or facing up though.
15" woofer? Eeeek!
And while the vertical off axis that you posted looks real good, that is typically not the problem I see. It's when it is crossed over to a woofer that time delay issues come up in the vertical off axis between the two drivers that cause holes in the response.
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These particular 15" or 18" waveguides wave guides work well with a 15" woofer. Time delay? The depth of the woofer and the waveguide are similar and if it's an issue it can be mitigated with dsp or adjust the cabinet a bit.
Well... I will soon see if it works 'cause I'm just finishing up my bass bins for the TD15Ms'. The SEOS18/compression drivers waveguides will be mounted on top in removable boxes that will allow a little adjustment for depth spacing. The SEOS18 holds pattern control to ~ 650hz. The 1" comp. driver I'll use goes down to 650hz so it'll be about there where I'll crossover. Since I'm crossing this low maybe time delay issues won't be so important.
If you go elsewhere there are many testimonials to the sound quality of similar SEOS based speakers. Geddes speakers employ a round WG which have a greater center to center distance than SEOS and he also had to deal with time delay issues too.
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These particular 15" or 18" waveguides wave guides work well with a 15" woofer. Time delay? The depth of the woofer and the waveguide are similar and if it's an issue it can be mitigated with dsp or adjust the cabinet a bit.
It actually doesn't work that way. With a big wave guide and a big woofer the center to center spacing can be 16" or more apart. Now you can use common DSP crossovers (which sound horrible) to adjust for time delay on axis and get them in phase. However, as you move a microphone up vertically you'll see that the change in distance between the two drivers will cause them to be out of phase and cause a cancellation that can be a 15db hole. So while the horizontal off axis looks great, the vertical can be a mess.
Well... I will soon see if it works 'cause I'm just finishing up my bass bins for the TD15Ms'. The SEOS18/compression drivers waveguides will be mounted on top in removable boxes that will allow a little adjustment for depth spacing. The 1" comp. driver I'll use goes down to 650hz so it'll be about there where I'll crossover.
That will be your saving grace (the low crossover point).
Since I'm crossing this low maybe time delay issues won't be so important.
650Hz is about 20.5" long wavelengths. If you can keep the acoustic centers less than that then it won't be too bad.
If you go elsewhere there are many testimonials to the sound quality of similar SEOS based speakers. Geddes speakers employ a round WG which have a greater center to center distance than SEOS and he also had to deal with time delay issues too.
I have heard that those have a significant hole in the vertical off axis, but have not measured a pair myself.
I think you have a good understanding of the principles. Hopefully it will work out well for you.
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Another problem that is always overlooked by these guys
Are you referring to these guys linked in the above article?
Credit where credit is due:
I first heard of time-intensity trading with speakers in an AES paper about
development of the DBX Soundfield One loudspeaker (google for more info).
Don Keele, Earl Geddes, Tom Danley, Wayne Parham, Duke Lejeune, and Zilch
have discussed these concepts, as applied to horn/waveguide based
loudspeakers, in various articles and forum posts..
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Are you referring to these guys linked in the above article?
Here is my whole sentence.
"Another problem that is always overlooked by these guys is that the biggest reflection point in the room is typically not the side walls. It's the ceiling. And you want just as smooth and even response in vertical off axis response as well as the horizontal off axis response."
Not referring to anyone specifically but with most large wave guide designs the horizontal is emphasized while the vertical off axis is overlooked.
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Another problem that is always overlooked by these guys is that the biggest reflection point in the room is typically not the side walls. It's the ceiling. And you want just as smooth and even response in vertical off axis response as well as the horizontal off axis response.
Wouldn't it be more optimum to have a tighter control of the vertical response since the the ceiling is typically closer to the speakers than the walls? It seems logical that an elliptical or rectangular WG would be better than a round WG for most rooms.
Granted you'd like a smooth and even response regardless. It follows that a typical dome tweeter generally has equal dispersion 360 degrees, therefore not the optimum for most listening rooms. In my situation, the ceiling is about 7'-10".
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Wouldn't it be more optimum to have a tighter control of the vertical response since the the ceiling is typically closer to the speakers than the walls? It seems logical that an elliptical or rectangular WG would be better than a round WG for most rooms.
Granted you'd like a smooth and even response regardless. It follows that a typical dome tweeter generally has equal dispersion 360 degrees, therefore not the optimum for most listening rooms. In my situation, the ceiling is about 7'-10".
The type of wave guide used usually isn't the issue. What I see often is a wide driver spacing and that of coarse means the crossover really needs to be lower to compensate for that, but it is not always the case. So when you move to a vertical position that represents a little bit of what you will get from a ceiling reflection then you see cancellation in that plane.
Here is an example of a speaker I measured that is time and phase coherent.
(http://gr-research.com/pics/TC-50%20vertical.jpg)
Unfortunately that coherency doesn't exist in the vertical plane. The drivers are out of phase.
So the ceiling reflection will show that.
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Here is my whole sentence.
"Another problem that is always overlooked by these guys is that the biggest reflection point in the room is typically not the side walls. It's the ceiling. And you want just as smooth and even response in vertical off axis response as well as the horizontal off axis response."
Not referring to anyone specifically but with most large wave guide designs the horizontal is emphasized while the vertical off axis is overlooked.
The most logical counter to the vertical response being as important as the horizontal response is the fact that we have ears on the sides of our heads and not the top and bottom. Is the vertical irrelevant? Of course not. Our brain is better at overlooking different arrival anomalies than others.
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These particular 15" or 18" waveguides wave guides work well with a 15" woofer. Time delay? The depth of the woofer and the waveguide are similar and if it's an issue it can be mitigated with dsp or adjust the cabinet a bit.
Well... I will soon see if it works 'cause I'm just finishing up my bass bins for the TD15Ms'. The SEOS18/compression drivers waveguides will be mounted on top in removable boxes that will allow a little adjustment for depth spacing. The SEOS18 holds pattern control to ~ 650hz. The 1" comp. driver I'll use goes down to 650hz so it'll be about there where I'll crossover. Since I'm crossing this low maybe time delay issues won't be so important.
If you go elsewhere there are many testimonials to the sound quality of similar SEOS based speakers. Geddes speakers employ a round WG which have a greater center to center distance than SEOS and he also had to deal with time delay issues too.
Do you have a build thread going on somewhere? Sounds really similar to my Pi4 build and Mikes modified 2226 design.
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Do you have a build thread going on somewhere? Sounds really similar to my Pi4 build and Mikes modified 2226 design.
No build thread yet. I'm not sure which forum to use for the build thread. I am documenting much of the build with photos.
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Are you referring to these guys linked in the above article?
Nice intentionally manipulated context! :duh:
-Jim