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Speakers Vertically Stacked

#123
Until the range it peters out and the main PA takes over it will have poor sound from all aspects. However much it muddies up the sub bass from the PA, the sub bass will sound bad everywhere. That's what physics predicts.

The bigger the gig the more you can get away with but it doesn't make it any better.
 
#125
billfitzmaurice said:
Where the speakers are within 1/4 wavelength of each other they operate as a single low frequency source, so their positioning with respect to boundary coupling makes no difference. That has to do with constructive versus destructive coupling of the midrange and high frequency outputs, where the drivers are too far apart to operate as a single source. This site has a number of applets that you can use to see the effects of using multiple sources at different frequencies with various spacings and orientations, with and without boundaries. Caution: it's very addictive, you can spend hours fiddling with it.
3-D Wave Simulation
Click to expand...

Thanks Bill, now I can see the theoretical basis that explains this behaviour. I will try to look at that site, keeping in mind that sort of addictive attitude...
 
#126
From [Invalid or Expired Link Removed]

There are two conditions for line source behavior. The first is that the line has to be at
least four times as tall as the wavelength it is radiating for a vertical pattern that is a
reasonable approximation of a plane wave. A second requirement is that the sources on
the line have to be less than 1/2 wavelength apart. This is the inverse of the first
requirement. Olson calculated in the 1940’s that two adjacent sources radiate a spherical
polar pattern (i.e. sum coherently) when they are less than 1/4 wavelength apart. Between
1/4 and 1/2-wavelength spacing the pattern narrows, but side lobes (interference patterns,
caused by destructive interference) do not appear until the spacing is greater than 1/2
wavelength


The length of 40hz is like.. 28 feet? Makes for a 96 foot speaker?
 
#127
I thought the line source had to be at least 1 wavelength long, not 4, although I'm certainly no authority on the subject. Meyer has a fairly easy to understand paper on this. Although it is a writeup on one of their line arrays, the tech stuff "sounds" solid.

Is this a similair relationship as what makes a truncated horn effective, as opposed to a full wavelength horn or am I way off base there...(likely the off base part).
 
#129
MaddAnthony_59 said:
Yes, Height is good. I like to put the Bigger Speakers on top. In theory it allows for the Bigger Waves to be released! In reality it at least looks cool to have an 18" speaker at Eye Level...
Click to expand...

I believe Billy Sheehan does this too since he moved to Hartke. In fact, I read that he uses the 4x10 for his low end, and 1x15 for high end as he preferred the softer tone and response of the 15.
 
#130
I recently purchased a Bose L1 Model II, but only have one B1 bass bin with it. I see on the Bose site, that guys are using them to play bass through. I do not use it for that, but will try my bass through just out of curiousity. I also have the T1 mixer which has some bass guitar settings on it. I already know that I would like to purchase another B1 because I feel it is lacking in the lowend department, for just music playback. With another B1 it would run the bass cabs at 4 ohms, which is where I have discovered i prefer my bass to run anyways. Anyways, I will have to try it out and see what it is all about.
 
#131
will33 said:
I thought the line source had to be at least 1 wavelength long, not 4,
Click to expand...
It's actually 3 wavelengths, and that's a vast oversimplification. There are other factors as well, as in every line source reverts to point source characteristics at some point, depending on both frequency and distance from the sources. And if you're paying attention you'll realize that all speakers are both line and point sources, depending again on the size of the radiating plane, frequency and distance from the source. Accounting for this fact is why speaker SPL charts should not be measured at 1 meter, because that close in the results are partially point source, partially line source, again depending on all the variables.
A second requirement is that the sources on
the line have to be less than 1/2 wavelength apart.
Click to expand...
Also an over-simplification. All that impacts is the distance from the line at which the waves from the sources fully integrate as a single front. That can be seen in the plots in this example from JBL:
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A full range true line array would be impractically tall for sure.
Click to expand...
True. But the benefits of line sources are greatest at the highest frequencies, and the size of the array required to get those benefits is quite small at the highest frequencies. The higher the better, yes, but that still doesn't negate the fact that even a two foot high source works much better than a one foot high source. That's because the increase in the effectiveness of a line is equal to the square of the increase in its height. Twice as high works four times as well. Four times as high works sixteen times as well.

JimmyM said:
It might to some, might not to others. There's really no way to predict it.
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Yes, there is.
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#133
billfitzmaurice
The wider the source the narrower the angle of dispersion. The ideal speaker would be about an inch wide and thirty feet high. That's not all that practical, though it has been done. The closer you can get to that ideal configuration the better. As soon as you put two drivers side by side you're headed in the wrong direction
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ok, I’ve searched everywhere and I can’t find any info about this speaker. How deep was it, was it a bass woofer, how many drivers, what drivers, etc - does anyone have a link?

will33
Don't know but it's likely a very tall array made up of dozens of 1" drivers. Impractical, yes, but not an overly complicated construct. And yes, you could get bass from 1" drivers, just very quiet bass, so you use lots of them.
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Yea maybe, I’d like to read more about the actual loudspeaker spoken of - have you seen any links? Thanks

Passinwind
Not to that one, but here's something roughly along those lines in the meantime. Be sure to follow the theory links, one of which gets you here.
Click to expand...
EDIT: added link Invalid Link Removed

Thank you Charlie. Hmm, interesting - so that’s the best bass speaker cabinet, wow who would have guessed.

Sparks55
$2,000 for the DIY kit, and the best they could do with specs is: "The system can be played extremely loud and remains very clean and effortless at all levels."

(Wish I could say this about my bass playing!)

Mark
Click to expand...

lol, and that's for only a 5 footer - BFM said the best is about 30ft.

And this one is wider than the 1”x30ft that BFM referred to (note: 3-1/2” drivers) and it has tweeters - but yeah, I would think they might sell more of these $2,000 DIY cabs if they listed the specs. I wonder if cab modeling software (WinISD reversed, etc) could be used to figure the approx specs but the drivers most likely need to be known - also, I wonder if the 1"x30footer that BFM spoke of had tweeters. My guess is the 1”x30ft cabs had tweeters and was built in a lab or maybe someone's home (some cool sound nerd‘s house). Anyway, if multi-drivers placed close together vertically actually couple together in a way that they act as a signal driver this cab is interesting - although it seems more like a stereo or PA type speaker than a bass guitar speaker.
 
#134
To me the biggest change in speakers has occurred because watts got so cheap. Today you can design loudspeakers with much more inefficiency because you can practically assume that the amp has unlimited watts.

KO

agedhorse said:
I agree with you 100% on the marketing aspect (hey, I'm an engineer... I'm supposed to roll my eyes at the marketing folks right?).

I do think there have been some tremendous improvements in speaker design, some things that I can think of that have pushed performance (including size and weight) forward are:

Neo magnet materials
Dual voice coil, push-pull motors
Inside-outside wound voice coils
Kapton bobbin material
Nomex/glass/epoxy bobbin material
fiber reinforced cone material
tall aspect ratio VC wire
titanium diaphragms
new phase plug geometries
Advanced horn flairs (CD, quadratic throat, waveguide)
lighter weight composite cabinet materials
advanced cabinet finishes
greatly improved hardware options
Click to expand...
 
#135
can you hear me said:
Quick question guys. What effect does diagonal placement, like the nv412, or gs412, have on dispersion and beaming? I assume they operate close to, but not exactly the same as a vertical stack?
Click to expand...
Dispersion is best when the radiating plane is as narrow as possible. Diagonal is narrower than side by side, not as narrow as vertical.
 
#136
billfitzmaurice said:
True. But the benefits of line sources are greatest at the highest frequencies, and the size of the array required to get those benefits is quite small at the highest frequencies. The higher the better, yes, but that still doesn't negate the fact that even a two foot high source works much better than a one foot high source. That's because the increase in the effectiveness of a line is equal to the square of the increase in its height. Twice as high works four times as well. Four times as high works sixteen times as well.
Click to expand...

+1
 
#138
billfitzmaurice said:
Yes, there is.
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Why you...I oughta.... :D

Obviously, if there's one thing this thread has proved, it's that not everyone cares about going by the book if they're happy with what they're getting. I was answering his question on a "Will you be happy with it" basis. The science is sound and reasonable...but we don't always pick our gear with the big head.
 
#139
JimmyM said:
Why you...I oughta.... :D

Obviously, if there's one thing this thread has proved, it's that not everyone cares about going by the book if they're happy with what they're getting. I was answering his question on a "Will you be happy with it" basis. The science is sound and reasonable...but we don't always pick our gear with the big head.
Click to expand...
Another view is that if you don't even know the book exists you can hardly expand your horizons by reading it. And that doing things 'because that's how we've always done it' is hardly a road map to improvement.
 

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