[guest42212]

1)
Rather than 2 'wings' back from the front sides of a baffle,
would 1 'wing' (twice the depth) in the middle be as effective ?

2)
Assuming #1 will work, would  'helper woofers' mounted on the
center 'wing' be effective ?

[JohnR]

Hi, when you say "wing" do you mean something that is slanted back from the baffle, or perpendicular to the baffle (like an H-frame)?

I'm also not understanding what you mean by "in the middle"... how can a wing be in the middle?   

But anyway, if you mean (effectively) moving the driver on a flat-ish baffle, it makes a difference. Below is a driver in the center of a baffle in green, towards the edge in red. This is using the Edge simulator.




HTH

[Rudolf]

Rather than 2 'wings' back from the front sides of a baffle,
would 1 'wing' (twice the depth) in the middle be as effective ?

What is "effective" about a wing in a dipole? It is the path length difference between
- the direct path from the front of the driver cone to your ears and
- the path from the back of the cone to your ears.
While the side wings would increase the path length for almost every sound coming around from the back, the center wing will only be effective for half the sound.

Rudolf

[Toaster]

Unless I'm visualising this all wrong, surely it would do absolutely nothing to increase the pathlength? It might stiffen the baffle though...

[guest42212]

Unless I'm visualising this all wrong, surely it would do absolutely nothing to increase the pathlength? It might stiffen the baffle though...

Call me old fashioned. I use the distance from the front to back of the driver to calculate baffle rolloff.
Fb = 360 / bafflewidth(shortest diameter(in feet))

[guest42212]

> I'm also not understanding what you mean by "in the middle"... how can a wing be in the middle? 

side wings ala ' U '      |___|

side wings ala ' H '      |___|
                                   |      |

my plan ala ' T '              |
                                  __|__
 
                                 

[JohnR]

my plan ala ' T '              |
                                  __|__

Like the driver in the lower left of this photo, except the "wing" is longer?

[guest42212]

Right, but no driver interfering with the wing-panel connection ....
Wing runs up full length of panel ..........

[JohnR]

Um, not sure what you mean by interfering, but is the driver half on each side of the wing? If so, then the front-to-back distance will be the same as with no wing.

[guest42212]

Left channel drivers to left of wing...........
Right channel drivers to right of wing.......

[MarvinTheMartian]

Mr, "T"
Your original question follows, and hence this threads confusion.

on: 27 Nov 2012, 05:48 pm »
Is there any reason not to put both channels on one baffle ?

Yes , that would be mono! or a HUGE baffle, the size of your front wall.
Shawn

[guest42212]

Right, I mentioned this before.
Since then I have tried the both channels on a single baffle part.
If the baffle is too big accross a dead spot appears in the center.
I can live with small seperation since I sit fairly close and in my
room everything seems to sort of localize in one corner anyways.
I've  tried this with an open back box, but it seems 'cloudy' at times.
(but the seperation is sufficient) (1/4 wave artefacts I think)
Hence I hope the ' T ' will extend the baffle without the pipe coloration.

[JohnR]

Well, it's worth a try, but I don't think you'll get a huge amount of extra bass, maybe 3dB at 100 Hz. You mentioned helper woofers in your first post, what about putting them on the lower part of the baffle?

[guest42212]

Well, it's worth a try, but I don't think you'll get a huge amount of extra bass, maybe 3dB at 100 Hz. You mentioned helper woofers in your first post, what about putting them on the lower part of the baffle?

Fine and dandy, but if the helper woofers could be on the wing ...
it would decouple visual cues to non single sourceness

[JohnR]

Hi, you'll be in the dipole null if they are oriented that way... there will still be reflected sound...

[Russell Dawkins]

I've always wondered why Gradient did the woofers that way in their Helsinki.

[guest42212]

Yeah.
Is it possible that since bass is omni-directional it has no null ?

[JohnR]

There is a null, but there is also reflected sound.  "Bass is omni-directional" because sound diffracts around objects that are small relative to its wavelength, like a loudspeaker/subwoofer box. However, when you have sound waves of opposite polarity and equal magnitude, they will cancel (and form a null). What you hear in-room at the LP is not just the direct sound though.

The Helsinki Gradient relies on the reflected sound in the bass region. Some measurements here:

http://www.stereophile.com/content/gradient-helsinki-15-loudspeaker-measurements

That reviewer had difficulty getting much bass output in-room. hitsware, it would not take much work for you to try it I got the impression that you may have a small room? Perhaps it would work well for you, you can let us know what you did