1200Hz Smith horns for 1" driver

[yggdrasil]

Mathias, there is also half a vane on each side, right next to the side panels.

What material did you use?

Nice work as always.

[MatthiasA]

oh its only a package tape

the Horn on this picture isnt finished!

now its finished
i fixed the sides and removed the tape!

[yggdrasil]

Finally got everything set up. Did a test a couple of days ago, to familiarize with the equipment.

The equipment:
- Laptop computer
- Behringer measurement microphone
- WinAirr

I am a little disappointed with the measurement. The equipment does not seem to be able to give exact measurements. I am installing a new computer, and I will try the test later with the new computer to see if it will be more accurate.

I will attach 3 graphs. All are done on the same equipment, with the same procedure.

1) Run 100 tests without signal, captured and subtract.
2) Run 100 tests average, white noise, 20 miliseconds, sample rate 48KHz

Pic 1 is Smith horn with LE85 equipped with D16R2425
Pic 2 for comparison is 2441 on a flat front biradial 238x
Pic 3 also for comparison is 2402

It seems they are good to 8Khz, maybe usable to ~13Khz.

[Ian Mackenzie]

Try theses settings.

Pulse excitation mode, frequency, average 100, sample rae 44khertz, sample length 2048.

Do not rely on the sound card mic preamp, use an external preamp and use a low diffraction mic. The diffraction will otherwisw give incorrect result.

I use the same Panasonic capsule as the Mitey mic on a 2 ft think alminium tube.

All the same the response is limited, my 800 Smith horns were also limited above 10K. I wonder if the throat may need some modifications. Any abrupt changes there will effect the final result.

Ian

[yggdrasil]

Hi Ian.

I have several points on my list to look into.

1) The vanes are not 100%
2) The finish is just plain particle board
3) as you say the throat.

Anyway now there is a measurement to work from.

I don't have a mic preamp now, but I don't have a line input on my laptop either. Will try again shortly with the new laptop, which is a HP. The old one is a brandless.

[Ian Mackenzie]

Okay,


Please keep us informed...and how does it sound?

Ian

[Mr. Widget]

All the same the response is limited, my 800 Smith horns were also limited above 10K.

Here is a plot of the stock 2387 (800Hz) Smith horn with 2441 and TAD 4001 drivers... they aren't dropping off up top like yours seems to be.

Widget

[Ian Mackenzie]

Oh come on, do you call 10 db down above 10 k or so extended?

You of all people should know better....Tad = miss information..=

My old graphs are some where on ice, however its obvious the diffraction loading gives up above 10 k due to the 2 inch gap.

Are you sure they are not the eq'd westlake horns??

Ian

[Mr. Widget]

I have no idea what you are trying to say.

I posted that plot simply to show how the "full sized" 2397 compares to Johnny's recent post.

As for the TAD vs. JBL thing... here is JBL's own published take on a comparison.

Widget

[yggdrasil]

Please keep us informed...and how does it sound?

To me they sound beautiful.

I threw out the H91's at once (Hong Kong).

I can't seem to get enough. I had been turning the L-Pads with just my ears to help me for some time. Measuring showed them at least 6dB up compared to the all the others...

Eventually I will get around to making a pair in birch or some other kind of wood I have lying, just waiting for a project.

[Mr. Widget]

To me they sound beautiful.

I threw out the H91's at once (Hong Kong).

That's great! I know the feeling.
Are they being augmented by the 2405s or are they fine on HF extension?

Widget

[Ian Mackenzie]

What I am driving at is will a diffraction/Smith horn go flat above 10K by design?

The Westakes Ken has have a one inch driver on what appears a mini Smith Horn ...the details I am not very clear on, but it would seem to go up above 10 khertz altough i have not seen the response graphs.

Anyone have data on this?

Ian

[yggdrasil]

That's great! I know the feeling.
Are they being augmented by the 2405s or are they fine on HF extension?

Widget

The 077's come in at 7K. The HF extension in my setup is not an issue.

Will make a new pair where I address the finish, vanes and throat issues. Then we will see if it is possible to use them over a wider range.

Would like to be able to set the crossover frequency to 10K to see if the integration will be different.

[yggdrasil]

What I am driving at is will a diffraction/Smith horn go flat above 10K by design?

The Westakes Ken has have a one inch driver on what appears a mini Smith Horn ...the details I am not very clear on, but it would seem to go up above 10 khertz altough i have not seen the response graphs.

Anyone have data on this?

Ian

The small Westlake's do not have the vanes.

It would be very easy to make a pair.

Will need measurements (height, width) and preferrably some pictures of the throat / transition.

I have been playing with the thought of making a tiny Smith horn and copy JBL's compression chamber from the 2403/2404. Then mount the whole thing on a ring radiator with a 2405 dia.

Would be very nice-

[Ian Mackenzie]

Perhaps we an ask Ken to take a close macro shot of his smaller Westlake horn.

Ian