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Concrete Bass Horn Design Question
Concrete Bass Horn Design Question
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Old 10th January 2017, 09:07 PM   #1161
1audiohack is offline 1audiohack  United States
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If it were me and I wanted something weather proof, I would consider a Community R6, a fiberglass six ea 12" driver front loaded bass horn with a three foot wide four foot tall mouth as a start and go out from there.

Food for thought.

Barry.
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Old 10th January 2017, 11:00 PM   #1162
j.michael droke is offline j.michael droke  United States
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Quote:
Originally Posted by 1audiohack View Post
If it were me and I wanted something weather proof, I would consider a Community R6, a fiberglass six ea 12" driver front loaded bass horn with a three foot wide four foot tall mouth as a start and go out from there. Food for thought.
Barry.
Hi there B: Community R6-Max looks like an interesting implementation, however, it falls short on low bass requirement stated by OP in post #1 (20hz vers R6-minimum of 44hz)., as found on Community's web site specification sheet. ...regards, Michael
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Old 11th January 2017, 01:28 AM   #1163
1audiohack is offline 1audiohack  United States
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Hello Michael;

Certainly right if the R6 was used by itself. I was thinking to use it as a horn throat (starting point) connected to the 20Hz concrete horn the OP imagines.

Barry.
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Old 11th January 2017, 01:19 PM   #1164
whgeiger is offline whgeiger  United States
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Default Voicing the Horns

Quote:
Originally Posted by 1audiohack View Post
Hello Michael;

Certainly right if the R6 was used by itself. I was thinking to use it as a horn throat (starting point) connected to the 20Hz concrete horn the OP imagines.

Barry.
Requires adjustment of:

1) Back chamber Volume

2) Throat Area

3) Front Chamber Volume

Especially if driver selection remains a fourth degree of freedom.

Materials to be used for this purpose includes pressure treated plywood I suppose. Just do not like abandoning concrete to enclose this high pressure area.

Instead I would design for a set of drivers that can deliver the desired operating parameters so that the nominal adjustments needed can be easily implemented.

For this application, where cost is apparently no object, the Power Soft M-Force 01 driver [1] looks most attractive.

WHG

[1] PSMF01/03
Attached Files
File Type: pdf PSMF01.pdf (391.6 KB, 14 views)
File Type: pdf PSMF02.pdf (215.6 KB, 10 views)
File Type: pdf PSMF03.pdf (888.3 KB, 12 views)
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Old 15th January 2017, 01:35 PM   #1165
weltersys is offline weltersys  United States
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Quote:
Originally Posted by whgeiger View Post
Materials to be used for this purpose includes pressure treated plywood I suppose. Just do not like abandoning concrete to enclose this high pressure area.

Instead I would design for a set of drivers that can deliver the desired operating parameters so that the nominal adjustments needed can be easily implemented.

For this application, where cost is apparently no object, the Power Soft M-Force 01 driver [1] looks most attractive.

WHG
Bill,

As previously stated, LP SmartSide is a wood product that is basically completely impervious to the environment- I have used it, unpainted, as an outdoor sidewalk directly on the termite infested ground with virtually no degradation over a period of 16 years.

The M-Force 01 with the 40" cone appears most impressive at a 3.67% efficiency as a direct radiator.
I have been reading about the M-Force moving motor concept for a few years, but have not heard any of their units yet, have you?

Art
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File Type: png M-Force 01 40".png (50.9 KB, 91 views)
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Old 15th January 2017, 07:03 PM   #1166
whgeiger is offline whgeiger  United States
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Hi Art,
Comments follow:
Bill

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Originally Posted by weltersys View Post
Bill,

As previously stated, LP SmartSide is a wood product that is basically completely impervious to the environment- I have used it, unpainted, as an outdoor sidewalk directly on the termite infested ground with virtually no degradation over a period of 16 years.
This paneling cannot be used alone to cover a shear wall. Other problems are discussed here: Many problems with installations of LP SmartSide siding - StarTribune.com. At the frequencies of interest, concrete is a far superior construction material. If the OP builds just one horn, its scale is going to dominate performance. If needed, replaceable driver manifold
segments can be designed to accommodate various multi-driver alternatives.

Quote:
The M-Force 01 with the 40" cone appears most impressive at a 3.67% efficiency as a direct radiator.
I have been reading about the M-Force moving motor concept for a few years, but have not heard any of their units yet, have you?
Art
Not yet. During my discussions with Power-Soft's US representative, the 30" cone was recommended for use in a large bass horn. The polypropylene cone is ideal for this particular outdoor application as it is impervious to all the hazards. The TSPs look suitable for driving a horn load as well.

For this project, how the frequencies above say 80 Hz. are reproduced is where the acoustic challenges are to be found. Below, the challenges are primarily those of concrete placement.
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Old 15th January 2017, 11:59 PM   #1167
hollowboy is offline hollowboy  Australia
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The linked (midhorn) build uses petals of 3mm ply for the shape, and then wraps it in synthetics (mostly fibreglass).

That seems like a good way to get a waterproof horn:

- fairly low material / effort / infrastructure / money requirements, relative to the result.
- could be kept light & mobile, or encased in other materials (such as concrete) for a permanent installation.

I have not worked with fibreglass before. For, say, a 150cm long throat section, or a 150cm long midbass horn, would anyone who knows fibreglass be able to give a guesstimate on how long the fibreglass part would take, and how much goo you'd need?

doityourselfaudio: 140Hz Petal Horns
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Old 16th January 2017, 02:10 PM   #1168
USRFobiwan is offline USRFobiwan
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Concrete Bass Horn Design Question
@Whgeiger The Powersoft Cones and M-drive are already used in different horn applications, bandpass and frontloaded designs from different brands. Function one F132, PK sound Gravity, D.A.S. Audio SF30 are a few of them that used the Powersoft design.
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Old 16th January 2017, 02:44 PM   #1169
weltersys is offline weltersys  United States
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Quote:
Originally Posted by whgeiger View Post
Hi Art,
Comments follow:
Bill
1)This paneling cannot be used alone to cover a shear wall. Other problems are discussed here: Many problems with installations of LP SmartSide siding - StarTribune.com.
2) At the frequencies of interest, concrete is a far superior construction material. If the OP builds just one horn, its scale is going to dominate performance. If needed, replaceable driver manifold
segments can be designed to accommodate various multi-driver alternatives.
3)Not yet. During my discussions with Power-Soft's US representative, the 30" cone was recommended for use in a large bass horn. The polypropylene cone is ideal for this particular outdoor application as it is impervious to all the hazards. The TSPs look suitable for driving a horn load as well.
4)For this project, how the frequencies above say 80 Hz. are reproduced is where the acoustic challenges are to be found. Below, the challenges are primarily those of concrete placement.
Bill,

1) Reuben Saltzman's October 6, 2015 article mentions "LP SmartSide® is the new high-end siding of choice here in Minnesota" and then goes on to list the installation errors, primarily unpainted surfaces.
I don't know how "new" LP SmartPanel was to my former Twin Cities location, but in the 17 years the LP SmartPanel laid in unpainted 18" wide cut strips (24' of sidewalk from one sheet ;^) ) on the ground in Madrid, New Mexico, there was virtually no wear, in fact, I brought some of the 17 year old pieces along to Florida to use for under trailer jacks.
The James Hardie siding, which looks so much like LP SmartPanel that I purchased some, went "wild" on the edges in a mater of a few years even though they were painted. It has little shear strength, while the LP SmartPanel is strong enough to make cable ramps from and have trucks drive over it (damn it...) all day.
2) Agreed, though the cost ratio of the cost of concrete, forms, rebar & labor for the marginal improvement compared to laminated LP SmartPanel is staggering.
3) I have been considering trying the 22" cone in the Keystone "B-Low".
4) Agreed.

Cheers,
Art
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Old 17th January 2017, 01:00 PM   #1170
whgeiger is offline whgeiger  United States
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Originally Posted by weltersys View Post
Bill,

1) Reuben Saltzman's October 6, 2015 article mentions "LP SmartSide® is the new high-end siding of choice here in Minnesota" and then goes on to list the installation errors, primarily unpainted surfaces.
I don't know how "new" LP SmartPanel was to my former Twin Cities location, but in the 17 years the LP SmartPanel laid in unpainted 18" wide cut strips (24' of sidewalk from one sheet ;^) ) on the ground in Madrid, New Mexico, there was virtually no wear, in fact, I brought some of the 17 year old pieces along to Florida to use for under trailer jacks.
The James Hardie siding, which looks so much like LP SmartPanel that I purchased some, went "wild" on the edges in a mater of a few years even though they were painted. It has little shear strength, while the LP SmartPanel is strong enough to make cable ramps from and have trucks drive over it (damn it...) all day.
My experience with engineered wood products is that when moisture invades the wood fibers, they expand and break the resin bonds that hold them together. Your experience with the LP Smart Panel product is encouraging.

Quote:
2) Agreed, though the cost ratio of the cost of concrete, forms, rebar & labor for the marginal improvement compared to laminated LP SmartPanel is staggering.
3)

The much smaller manifold segments can be formed using remnant materials, thus the costs of building the much larger horn bodies prevail.
For segment design, see attachment [1] from an earlier post

Quote:
I have been considering trying the 22" cone in the Keystone "B-Low".
SWAG: Unless you need the higher mass roll-off frequency, recommend the use of 30" diaphragms.

>snip<

Regards,

Bill

Reference [1]
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File Type: pdf TAQOS.pdf (534.2 KB, 4 views)
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