Need Help

[jayrjoe]

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[tb46]

Hi jayrjoe,

Take a look here: http://www.diyaudio.com/forums/subwoofers/143714-lab12-tapped-horn.html

Regards,

 

[jayrjoe]

Hi jayrjoe,

Take a look here: http://www.diyaudio.com/forums/subwoofers/143714-lab12-tapped-horn.html

Regards,

Hello Oliver,
Wow, thats quite a very big and heavy enclosure.

I am now finalizing to make my snail horn, the weight is tolerable and can possibly be used outside too, the only thing that's a bit complicated is the cutting of angles since we have no cnc cutting machine in my place.

 

[jayrjoe]

An externally hosted image should be here but it was not working when we last tested it.

Hello Oliver,

I did some changes of my SMTH118 with 40 inches height.
Will there be a significant improvement of the response curve compared to my initial drawing?

By the way back to horn resp, how did you compute area for S1, S2, and so on.
For example your S1 = 959 but my computation is only 851.

 

[tb46]

Hi jayrjoe,

Post #24: "...how did you compute area for S1..."

Duct height times internal width equals area.

Your drawing in Post #1 specifies 6.8" for the duct height @ S1/S2; redrawing the box S1 ended up w/ 6.7", probably some kind of rounding error somewhere, that's why I usually add a few positions past the decimal point to the dimensions. The internal width from your drawing: 22.2". It's easy to put the dimensions into a spreadsheet, see attached.

Regards,

 

[GM]

Correct, though you will find more deviation from the sim as frequency increases at the upper end of the planned passband.

Depends; use enough partitions, each with the right WL, area like Olson's circa 1940 BLH studio monitor realization of this patent did, which loaded up to ~500 Hz IIRC. Wish RCAfan was still alive or at least all his designs, measurements posted as he had some for it and was one of the flattest BLH in room responses I've seen: https://www.google.com/patents/US2224919

Wonder if anybody here saved a copy.......Freddy?

GM

 

[jayrjoe]

Hi jayrjoe,

Post #24: "...how did you compute area for S1..."

Duct height times internal width equals area.

Your drawing in Post #1 specifies 6.8" for the duct height @ S1/S2; redrawing the box S1 ended up w/ 6.7", probably some kind of rounding error somewhere, that's why I usually add a few positions past the decimal point to the dimensions. The internal width from your drawing: 22.2". It's easy to put the dimensions into a spreadsheet, see attached.

Regards,

Many thanks Oliver for the clarification and detailed excel table.
I modified the drawing and use 0.75inch instead of 18mm. Converting 18mm to inches is only 0.71 inch. So there are some differences.

Best Regards