Lab12 - Tapped Horn -

[ashok]

Thanks for your comments Don.


Jogi59, can you please put up the URL for that picture.

I get a blurb saying " No hotlinking allowed !"

It says " use the first link after the completed upload ". I guess you know what to do .

Maybe this is an opportunity to sort out the differences between the two implementations. I'm sure each has its own merits and demerits. However the conclusions will help in choosing the solution for others who have not made the comparisons themselves.

Cheers.

[JLH]

Originally posted by Don Snyder
Now, lets turn up the power ...

1. What happens when the port chokes?
2. Doesn't the vented box run out of xmax first?

Ditto

[jogi59]

Originally posted by Don Snyder
1.What happens when the port chokes?

In a 300 liters box is enough space for big enough ports

Originally posted by Don Snyder
2. Doesn't the vented box run out of xmax first?

No
the tapped horn runs out of Xmax first

Visaton in germany measured a tapped horn and a vented box of the same size in their anechoic room. The surprising result was: the vented box went louder

[tb46]

Post #13

Hi joqi59:

Very interesting data. That has to be one big anechoic chamber to reach down to 20/30Hz.

Looking at the left hand graph (1W/1m?), I doubt that this is a well designed tapped horn. It would be nice to get more data on the build.

Do you have any more information pertaining to the tests, e.g.: which woofer was used, enclosure's layout, drive power?

Regards,

[JLH]

I think a size distinction needs to be made here. If you are willing to live with a 300 L box, then maybe a ported enclosure is fine for some people. However, the main advantage to the tapped horn is its ability to play low, clean, and loud in enclosures smaller than what is needed for a ported box. Regardless the sizes, the tapped horn is more musical because it has a broader tuned bandpass than a ported enclosure. I've never heard a ported enclosure play anything but one note bass. That's what happens when you only have a tuned port to work with.

[jogi59]

Originally posted by tb46
[B]Very interesting data. That has to be one big anechoic chamber to reach down to 20/30Hz

.

Originally posted by tb46
[B]Looking at the left hand graph (1W/1m?), I doubt that this is a well designed tapped horn. It would be nice to get more data on the build.

Don´t forget, that the measurement was done in an anechoic chamber=fullspace=4.0xpi in hornresponse.
To compare it with hornresponse simulations, add 12dB (1.0xpi) or 18dB (0.5xpi)

Originally posted by tb46
Do you have any more information pertaining to the tests, e.g.: which woofer was used, enclosure's layout, drive power?

The original thread is here
http://www.visaton.de/vb/showthread.php?t=18417
Simulation is in post 28
Enclosure in post 40
Used driver
TIW 300

[Chris8sirhC]

Those pictures look very familiar...

I did some corner braces (piece of wood 2''x2''x12'' on each of the inside fold corners. I also filled in that gap with expanding spray foam after it was completed. That space would be perfect though, for putting in a resonator or two, once you had figured out the correct length/tuning/etc.

I am thinking of having mine in a corner firing into the room through an opening in the door, and I would need to put on a small mouth extension to the horn. I am wondering if this would lower the tuning much.

[tb46]

Hi joqi59,

Neat chamber picture. :-)

As to the 1W/1m curve of the TH: I was talking more about the shape of the curve than about its amplitude.

Thanks a lot for the links and the driver info.

Regards,

[Don Snyder]

The TIW300 has an Fs of 25Hz. Optimal frequency for a Tapped Horn is .707*Fs or 17.6 Hz. This driver doesn't appear to be a
good choice for a tapped horn, especially a 30Hz Tapped Horn.

Might I suggest a Beyma 12LX60 in a 30Hz Tapped Horn.

[Don Snyder]

Here is my layout for the Beyma. Use the Beyma, it's much better than the Definimax.

With a little polyester fiberfil (1" thick) and a little EQ, this horn is usable from 30 to 150 Hz.

Can you say "apples and oranges?"