| Hi collo,
Wow, thanks for your detailed reply. You've communicated a treasure trove of specifics I've not seen elsewhere, and thanks too for thinking of my room, frame size and searching out some possibilities, especially with the higher N-prime QRDs. I was stumped earlier, feeling that the best dimensional fit was using only 8 periods of N11 --- a bad thing with the repetition.
Looking everything over, Let me throw this idea out, see what you think -- working with approx. 93.5cm (3') frame size:
Assuming these dimensions (all just as before):
well width = 4cm
well depth (max) = 13.5cm
fins = 2.5mm
frame = 91cm H x 91cm i.d., 93.5cm (o.d.)
(o.d. = if left+right wood-framing members, 12.5mm each, are added).
4 frames = 375cm (12'4") length coverage.
Ok, so a well-segment is defined as: 4cm + 2.5mm fin = 4.25cm.
Then, 22 well-segments = 93.5cm -- a perfect fit. This is why 2 periods of 11N works nicely.
As the 4 frames will mate up against each other, the two adjoining frame pieces = 2.5cm potentially of 'zero well dimension'. Let's say I now add a solid wood spacer of 1.75cm between the frames, making a total zero-well dimension of 4.25cm = one well-segment. Bear with me, I will try fitting an N23:
The N23 will have 11 wells in one frame, 11 wells in the next, and the zero well across the adjoining frame members (plus small spacer) at its midpoint.
Using four frames, put 1.75cm spacers wherever an N23 spans two frames (or in other options, put the zero well hard left or right, and add spacer; see further below):
Frames:
1 [spacer] 2 3 [spacer] 4
This creates the extra zero well, so just adjust your N23 zero well by shifting the N23 pattern over by 11 places.
Now this can be built:
[----1---]|[---2--][----3----]|[--4---]
A. N11+N2\3 + N11|+ N11 + N2\3 + N11|
Arrange the N23 to span frames 1+2, with the zero well right on the frame(+spacer) itself. So the first 11 wells of N23 are in frame 1 and the last 11 wells of N23 are in the first half of frame 2. Fill the last half of frame 2 with an N11. Follow the pattern again for the last two frames. Note that the repeating symmetry is broken up, though I'm not sure about the symmetrical N11 at the center. (See other options below.)
I mention the N23 because on my calculator it seems to have a surprisingly low LF for its period: "Approximate frequency range: 997 - 4318 Hz" (effective to 500Hz or so).
What do you think?
Using the same logic, and putting N23 zero wells across two frames (with a spacer) It's also possible to build:
3x N23 + 2x N11 (3 spacers):
B. | N23 | N11+\N23\|/N23/+N11 | N23 |
2x N23 + 4x N11 (2 spacers):
C. | N11+N11 | N23 | N23 | N11+N11 |
2x N23 + 4x N11 (2 spacers):
D. | N23 | N11+\N23\|/N23/+N11 | N11+N11 |
2x N23 + 4x N11 (2 spacers):
E. | N23 | N11+N11 | N23 | N11+N11 |
('\ /' indicates half of the N23)
In C. N23 zero-wells are shifted left/right; in E. shifted right/right.)
If this idea is acceptable, then 22 well-segments of 4.25cm each in the 93.5 (3') length frame looks pretty good. Though I'm not sure which of the patterns (A~E) is best ... though B. or A. seems most appealing.
If this isn't crazy... I think it's also possible to add 'zero-well' material to each end of the full array, if necessary, which will make a kind of, er, meta-frame decor.
stike |