LIVE SOUND Specific Tapped Horn thread...

[tb46]

Hi Don,

I certainly don't mind somebody keeping me honest. That's at least one of the good things about these threads.

Regards,

[MikeHunt79]

I dont suppose you post your input parameters please? I wouldn't mind seeing how the Ciare 15.00SW sims (even tho I know it will probably perform differently to the sim), cheers.

[tb46]

Hi MikeHunt79,

Sreamerusa has documented his design in:

http://www.screamersusa.com/furybox.html

and the transfer page has his Hornresp Input screen.

In Post #530 I added my 2 cents with a drawing, and in Post #534 screamerusa pointed out the angles of the internal reflectors. This led to the updated drawing in Post #535 which also contains the Hornresp input values in tabluar form.

I'll attach my Hornresp Input screens for Post #579's SPL curves. As to the Ciare 15.00SW: it looks like a very fine speaker. It would be nice to hear the input of some of our PA-Pros on that subject.

Regards,

[fb]

Originally posted by tb46
Hi fb,

Here is another take on building a tapped horn for the AV12H to your specs in Post #519. This one models well CON and EXP. Seeing the difference in response between screamerusa's measured results and the Hornresp model, I'd use OSB for a trial run. :-)

Regards,

tb46, thanks! I only just noticed your reply by chance I think I may have to do trial runs. At least the driver's sorta versatile. Do you have an example fold for the L23=L34 design?

Originally posted by fb

Is y = e^x the form of the equation to calculate the area at a given distance along the path?

My maths brain is broken.... is there a more specific way to work this out? I only have three data points, S2,S3 and S4.

[GM]

Well, the math is beyond me and why I use a proprietary Excel SS someone designed for me, but you can use an on-line Java applet such as this one.

Input S1 in the 'throat' box, input the flare frequency from F12, etc. except ignore any marked '0'. If you choose to use more than one flare frequency, then you'll have to plot each one individually. M = 1 since HR only does pure exponential flares in TH mode whereas the more appropriate flare factor would be a much lower hyperbolic/exponential one, hence a lot slower expansion (longer) for a given throat/mouth area. cab width would normally be the SQRT of the mouth area to make it square, but then the throat area would have a high aspect ratio which may be either a plus, minus or neutral condition in a TH, but I've no experience yet, so Caveat Emptor. For sure, the high aspect ratio mouth that a square throat yields will affect its HF performance, controlling its output like any other slot mouth, so unless someone proves otherwise, having some extra acoustic resistance back at the throat due to a high aspect ratio seems like a plus to me.

GM

[tb46]

Hi fb,

I don't have a fold for that particular model.

As to the area at a given distance: how about using the export function when viewing the schematic diagram? That should get you close enough.

Regards,

[GM]

Hmm, didn't think about the EXPORT function, but when I went to test it using the expo sim I did for fb, I couldn't get it to work.

GM

[Patrick Bateman]

Originally posted by GM
Hmm, didn't think about the EXPORT function, but when I went to test it using the expo sim I did for fb, I couldn't get it to work.

GM

Works for me. Did you add the first line? (Horn resp doesn't include it.)

Akabak is tricky, but the export function from Hornresp makes it a heck of a lot easier.



System 'S1'

|DATA EXPORTED FROM HORNRESP - RESONANCES NOT MASKED

|COMMENT: AE AV12H-4 16.97-184.62 expo TH

|================================================= ================================================== =====

|REQUIRED AKABAK SETTINGS:

|File > Preferences > Physical system constants:

|Sound velocity c = 344m/s
|Medium density rho = 1.205kg/m3

|Sum > Acoustic power:

|Frequency range = 10Hz to 20kHz
|Points = 533
|Input voltage = 2.00V rms
|Integration = 2Pi-sr
|Integration steps = 1 degree ... 1 degree
|Integration method = Cross

|================================================= ================================================== =====

Def_Const |Hornresp Input Parameter Values
{
|Length, area and volume values converted to metres, square metres and cubic metres:

Rg = 0.10e-0; |Amplifier output resistance (ohms)

S1 = 70.39e-4; |Horn segment 1 throat area (sq cm)
S2 = 70.39e-4; |Horn segment 1 mouth area and horn segment 2 throat area (sq cm)
S3 = 1414.21e-4; |Horn segment 2 mouth area and horn segment 3 throat area (sq cm)
S4 = 1634.17e-4; |Horn segment 3 mouth area (sq cm)

L12 = 0.10e-2; |Horn segment 1 axial length (cm)
L23 = 483.98e-2; |Horn segment 2 axial length (cm)
L34 = 23.32e-2; |Horn segment 3 axial length (cm)

|Parameter Conversions:

Sd = 471.00e-4; |Diaphragm area (sq cm)
}
|================================================= ================================================== =====

|Network node numbers for this tapped horn system:

|0-Voltage-1-Resistance-2
| |
| -Driver--
| | |
| 8-Segment-9-Segment-10-Segment-11-Radiator

|================================================= ================================================== =====

Def_Driver 'Driver'

Sd=471.00cm2
Bl=17.77Tm
Cms=2.18E-04m/N
Rms=6.76Ns/m
fs=24.0001Hz |Mmd = 195.83g not recognised by AkAbak, fs calculated and used instead
Le=0.28mH
Re=2.70ohm
ExpoLe=1

System 'System'

Resistor 'Amplifier Rg'
Node=1=2
R={Rg}

Driver Def='Driver''Driver'
Node=2=0=9=10

Duct 'Horn segment 1'
Node=8=9
SD={S1}
Len={L12}
Visc=0

Waveguide 'Horn segment 2'
Node=9=10
STh={S2}
SMo={S3}
Len={L23}

Waveguide 'Horn segment 3'
Node=10=11
STh={S3}
SMo={S4}
Len={L34}

Radiator 'Horn mouth'
Node=11
SD={S4}

[GM]

I was using the schematic diagram to get a .csa file of the horn's contour, but the pop-up windows displays the wrong info, so won't allow me to save it.

GM

[tb46]

Hi GM,

I just tried it again and the export function seems to work.

Let's see, in the Schematic window: File, Export, then from the right: I'm entering Uni under Width Flare, increments that match with inches (0.079/2.54/2.54/0.635), leave the Width alone, and set all the Height inputs to one value (e.g.: 35). Hit OK. Click csv button. Type in a name (up to 8 characters only), and hit save. The file is stored in the C:\Hornresp\Export folder. Open file with Quattro Pro (or your favorite spreadsheet), and everything looks fine.

Well, I have to run, may not be back until June.

Regards,