Dual 8" tapped horn = TH-SPUD

[geitmans]

I used more or less the same dimensions as the original

I managed an impedance measurement today. Tuning seems quite low, so maybe a bit too much filling. To do a freq respons measurement will take more time as I am not able to lift the heavy thing outside on my own.

[myn]

Thanks for the impedance graphs. As much as I am sure everyone would love to see outside measurement graphs. An inside one would be okay to pacify us for a little while!

Nice work

[tb46]

Hi geitmans,

That's a great workup you put together here. Very well done!

Did you end up using plywood, and would you please post a closeup of the driver/access port area? Any more FEA analysis plots you could share? Looking forward to your response measurements.

Regards,

[geitmans]

I used birch plywood because it seemed its quite a bit more stiff than OSB. The FEA plot remains the same only the first resonance mode went up to about 200Hz. I haven't done yet tests to see how close this is to reality.

Here is a detail of the access ports. I used threaded inserts and M4 screws to connect everything.

[tb46]

Hi geitmans,

Thanks for the close-up, nice work.

Regards,

[geitmans]

Here is a first measurement in my living room with the mic close to the mouth (mouth upwards in the middel of the room)



Tuning is indeed a bit low. I suspect the big dip at 60 Hz is a room effect. The stuffing does quite a good job filtering away the highfrequency content.

[just a guy]

Mouth up in the middle of the room is probably the worst spot in the room to measure from. Maybe try moving it around a bit and see if you can get rid of the big dip. Moving it outside and measuring should do the trick. That dip shouldn't be more than about 6db deep in my estimation.

[tb46]

Hi geitmans,

The stuffing seems to be doing it's job. The big dip is most probably a room effect, and it doesn't help that it coincides with a big dip in the hornresp SPL response curve. Turning the port to the floor, and changing the position will change the position of the room effect.

Regards,

[mwmkravchenko]

You realise you almost squeezed out three octaves between 15hz and 120 hz!

That's pretty good geitmans.

Mark

[myn]

WOW really impressed with both your 3D drawing and you're preliminary response graph.

How does it sound? Hows the sensitivity and SPL?

Regarding placement, have you tried corner loading them similar to this:




Very excited to see these positive results

Great contribution.