Welcome to the gallery;

This page has the first 5 CAD versions of my 28 Hz bass horn (there are some pre-CAD versions, I may post them someday). They are all based on the same mathematical throat model but do have differences in back chamber volumes and throat length. Version 2 had a serious flaw but I went ahead and included it as part of the sequence. Version 4 has some overlays of the throat model that show the layout/folding process I use. The color scheme is odd but I did not take as much time in the conversion process to make them nice and presentable (or printer-friendly).

An accessory mouth extension/reflector for use with pairs away from (or in) room corners is desirable for this design, with 800 watts power capacity per cabinet, many smaller venues don't require multiple pairs, but need to extend the horn's throat and increase it's mouth area, thus it's lowest cutoff frequency for useable, smooth frequency response (undersized horns suffer from rippled frequency response). v.6 has 160.8" throat and 3.802 x mouth area. Alternate  has 3.389 x area with diagonal cut so non-constant length. QuadPod is full 32Hz horn.
I think corner loading can be accomplished best by locating the horn 42" from the corner, facing the corner with the horn mouth's edge against the wall and the cabinet making a 30 degree angle to the wall (mouth makes the complementary angle of 60 degrees). You've been a BAD horn, stay in that corner!

Instead of the K.I.S.S.! and R.A.M.midbass, check out the newest midbass as of April 22nd, 2001!
EV DL12X data; K.I.S.S.! midbass EV DL12X response; K.I.S.S.! midbass
version 1 My first midbass horn design (designed to sit on the Classic)
K.I.S.S.! midbass; 90 x 40, single driver, matches EV HP9040 horn
v.6 mouth expander/corner adaptor
version 2
Alternate expander (economy model)
version 3
Interesting midbass; smooth response but quite complex
THE QUAD POD
version 4
Floor wedge from 1980
Predicted response of QUADPOD in free air, full array will be smoother. Sensitivity will be 9 dB higher than shown, I  had to scale the data to fit.
version 5
Panel cutting drawings
A recent midbass, Excel chart: view 1, view 2
WARNING: use of fewer than correct # of boxes WILL RESULT in troughs @105 Hz and below up to 4 dB deep at ~1/2 octave intervals! (proper # of boxes is location dependant)
Errata: corner horn size advantage factor is 8 to 1, not 4 to 1. Therefore only 2 corner loaded cabinets make a full horn, not 4.
Disclaimer: material presented AS IS with no performance/liability warranty.
My design is comparable to a hypex expansion with M=0.325 (M=0 is hyperbolic, M=1 is exponential). I made up an equation using the hyperbolic cosine function when I should have squared it, because my original objective was hyperbolic. However, when I recalculated the increased throat length convinced me the original flare was an acceptable compromise to my goal of extending low end response below exponential's capability. It is probably a good thing because of the higher distortion in hyperbolic horns, the explanation I've read is that this is due to local variation in the speed of sound as pressure waves travel along the horn, modulating frequencies. You may notice I quit calling it a hyperbolic horn in the later versions. The final design throat length of both versions 5 & 6 is 9' but the conventionally drawn centerline measures only 104". v.3 has >125" throat, but has more reflections/folds and may be more difficult to construct. For the curves in v.6 I plan on molding them with urethane foam behind curved veneer as a form.
Longthrow midbass data
Longthrow midbass response
mid horn v.1 - 200Hz flare, 300Hz cutoff 36 x 20 degree dispersion pattern
mid horn v.2 - 213Hz flare, 300Hz cutoff
all walls are elliptical and corners too
mid horn v.3 - 213Hz flare, 300Hz cutoff
circular sides and corners, elliptical top and bottom flares, tighter vertical pattern
tweeter horn, 36 x 20 degree dispersion
I now have a tiny digital camera-Agfa CL18, so here's photos;
Pic of 8" 3-way (what a blimp, but flat to 28 Hz!)
Picture of 6.5" 2-way (passive radiator)
25 ft^3 photo 3 6.5" on wall bracket for surround
25 ft^3 photo 1 25 ft^3 photo 2
My Rack 1 My Rack 2 George Gracie George & Gracie (page 3) More stuff
I revised my original midbass; DL12X in original plus trapezoidal version. Reduced mouth & added front chamber to flatten response. Still oversized but cannot shrink more and keep 12" speaker capacity.
Trapezoidal revision of my first midbass
Original; DL12X response
Original; DL12X data
Revised; DL12X response
Revised; DL12X data
McBean's program helped me refine the following 18" design. I started with too large a mouth area which caused response to sag above 100 Hz. Shrinking the mouths (since I couldn't lengthen the throat w/o a truly mammoth box) combined with the large front chamber (40% of back chamber's size) extended both the high AND lowend rolloff points as well as smoothing the response in and out of the passband. I wonder if a 21" woofer will fit?
18" bass horn 33"x46"x46" (The Lease Breaker). 1 in corner (= 8 in free air) hits 34 Hz @ -3dB, 2 not in corners (= 4 in free air) make 37 Hz. Maximum output/cabinet is 134 dB (250 watts/1 meter) with JBL 2240G woofer. The large front chamber controls rolloff;  +/- 0.4 dB, 38 - 185 Hz, +/-0.1 dB 40 - 100 Hz
License includes a detailed cutting diagram. Be aware that most interior doorways are less than 33".
JBL 2240G response - 1 in a corner
JBL 2240G in new horn: data
JBL 2240G response of 2 on floor JBL 2240G response - 1 on floor
Here is my midbass flat from 100 to 500 Hz (not a freebie). It is 4' deep because of the 100 Hz cutoff frequency. I designed it for the EV DL12X  but I include response plots for the EVM10M and JBL K120, which are not quite as flat (1.2 dB window). The shallow height means it acts as a diffractor for vertical dispersion (I am dealing with wavelengths from 11' (100 Hz) to 27" (500 Hz)). For stacks of 4 cabinets the dispersion should be 90 x 35 degrees. There will be 50 degrees of lateral pattern overlap for tangent placement. Short wall = good carry handhold height. So far I am undecided as to the best location for the speaker access plate.
Robinson Audio Midbass: R.A.M.
EVM10M/DL12X response overlay
R.A.M. data for DL12X
Response with DL12X K120/DL12X response overlay
Free air response for a single cabinet, still highly acceptable!
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