Acoustic Horn Design - The Practical Way

[Frabor]

Still printing in a ender 5? The print is taking a week.it has failed twice so far due to multiple issues. 90 per cndt now, will be ready hopefully tomorrow

 

[Dave Zan]

...ARTA with a Scarlett 2i2 sound card and a MicW 215L measurement microphone....

Have you found the MicW 215 satisfactory?
I plan to measure some prototype horns and the MicW215 looks like a nice choice.
The prototypes will be foam, probably XPS, I noticed a few people have tried this, any advice or tips on easiest fabrication, before I start?

Best wishes
David.

 

[bidland]

Have you found the MicW 215 satisfactory?
I plan to measure some prototype horns and the MicW215 looks like a nice choice.

Best wishes
David.

Yes, I like it.
I use the L-version with lower sensitivity. We have sold well over 100 of these for an SPL-logging application, and it was best to get the low sensitivity version to be able to record peak SPL in the +130dB range without overloading the input of the Scarlett 2i2. There has been very little problems with these in the field.

The mic comes in a box with a mic holder and a foam wind screen. They include a calibration chart and a correction file on a USB stick.
The mic holder is not well designed. It tends to come apart in pieces when you take it off the mic stand...
Not a big deal as long as there are alternatives.

--
Bjørn

 

[Dave Zan]

I use the L-version with lower sensitivity. We have sold well over 100 of these

I was unaware there existed a low sensitivity version, what is the sensitivity?
What price do you sell them for?

include a calibration chart and a correction file on a USB stick.
The mic holder...tends to come apart in pieces when you take it off the mic stand...

The one I am offered doesn't seem to have a correction file.
No problem, I can create one from the calibration chart, but I suspect it is because the mic is old stock that has sat on the shelf for years.
Should be stable by now
The mic holder is also no problem, I won't use it anyway, just an extension tube out the back to minimise reflections.

Thanks for the information and best wishes
David

 

[bidland]

I was unaware there existed a low sensitivity version, what is the sensitivity?
What price do you sell them for?



The one I am offered doesn't seem to have a correction file.
No problem, I can create one from the calibration chart, but I suspect it is because the mic is old stock that has sat on the shelf for years.
Should be stable by now
The mic holder is also no problem, I won't use it anyway, just an extension tube out the back to minimise reflections.

Thanks for the information and best wishes
David

Retail price here is 500 USD.
Low sensitivity version is 11mV/Pa. Standard version is 40mV/Pa.

Send a mail to Vincent at MicW with the serial number.
Maybe he has the correction file in his archive.
guowei (at) mic-w.com

--
Bjørn

 

[jzagaja]

Working on speaker for my father. STH260 with Tymphany DFM-2535R00-08 below.

 

[turk 182]

sure hope it sounds good, cuz it's butt ugly!!

 

[jzagaja]

Ugly shape?

 

[kipman725]

I like it and it answers a question I had about whether this style of waveguide protruding from the baffle has good results.

 

[jzagaja]

It seems protruding waveguide creates nulls between 1-2kHz and up. Higher H3 distortion wasn't confirmed in my measurement:

Grand Comparatif de Compressions 1 pouce - JustDIYIt !

 

[AllenB]

Still, it is in the right proportions and the result is good.

 

[U101222]

Ugly shape?

To be absolutely honest, I think it is ugly. Do not take it personally, please.

 

[U101222]

Working on speaker for my father. STH260 with Tymphany DFM-2535R00-08 below.

Wait, no, in person it is actually ok. Not a stunning beauty but quite ok! I retract my judgement on the CAD.

 

[jzagaja]

Thanks for honest opinion. I've made quick crossover 2nd/1st (tweeter/woofer) and sounds pretty nice.

 

[U101222]

As you see I have revised the opinion after seeing it. The CAD does not give it justice. The measurements look nice!

 

[jzagaja]

Not too much leaky bass reflex cabinet? See woofer impedance below.

 

[FlamingBeatz]

First, let me summarize how to import the shape into Fusion 360 since it is still not properly documented in the User Guide.


Definition file parameters (4.5.0 and above)

Output.Coords = true
Output.Coords.NumProfiles = 8 ; Number of exported curves in "_profiles.csv" file (default = 4)

Notes

Two files are created in the project folder:

<project_name>_slices.csv
<project_name>_profiles.csv

Now there are two Add-Ins for Autodesk Fusion 360 included in the Ath package:

Ath4_CurvesImport - used for spline-only import, can be used either with the "slices" or the "profiles" file
Ath4_SurfaceImport - used for lofted surface creation from the "slices" file.

The number of curves in the "slices" file is controlled by Mesh.DepthSegments parameter.


Installation of the Add-Ins in Fusion 360

1) Tools -> ADD-INS -> Scripts and Add-Ins
2) Click "+" in "My Scripts"
3) Select the folder "CurvesImport", part of Ath package
4) Repeat steps 2-3 for the "SurfaceImport" folder, part of Ath package

Hi Mabat,

Is it correct that this is still not included? Could you maybe let me (us) know how a Fusion 360 import can be done with the current version? I cannot find the import scripts within the ath package.

 

[FlamingBeatz]

Ok, figured it out by going through your other thread.

Included the following in my file and found the scripts in your previous version of ath.

GridExport:f360 = {
ExportProfiles = 0
ExportSlices = 1
Scale = 0.1
}

 

[Antoine8082]

Hi All,

From a message, posted at the wrong place : https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-7011214

The Horn is printed (PET Carbon) !
It look good.

Now, 50h of printing is needed for other parts.
I'll post some photos if you have interest.

 

[Drofdissonance]

Antoine, i'd love to see the predicted polars if you can post them!