Horn Honk $$ WANTED $$

Status
Not open for further replies.
If compare this to the jzagaja's JMLC horn, this is much cleaner.
The driver/horn integration seems to have a key role here!?

From these measurements and mine, it certainly seems so! The TAD on the good horn is so much cleaner than any other.

I'm going to try 4 different drivers on the 811 horn and will post the results. All Altec drivers, but different magnets, diaphragms, etc. Should be interesting to see what the noodles reveal!
 
ALtec 811 sweeps

As promised, here are 3 new sweeps of the Altec 811B horn.
Sweeps have an active 250Hz HP (Butterworth)
I ran thru 3 pairs of drivers (6 total) and picked the best looking sweep for each pair.

Included are:
Output of amp across voltage divider for reference
806A aluminum fram
802-8? Aluminum fram
802-8D Symbiotic fram

All on the same horn, same amp, same drive level. Voltage divider of 8R series, 8R shunt. HOLMImpulse calibrated with amp output across voltage divider.

This may help show the difference drivers can make on the same horn. And these are all Altec alnico drivers made for this horn.
 

Attachments

Sandbag Removal:

Let's see how some obvious changes are reflected in the wavelet. Here's the original rendering with the full 5ms windowed bandwidth:

attachment.php


Now, remove the second developmental speaker that was sitting next to it:

attachment.php


Finally, put foam insulation on the protruding edges of the cabinet, making them more prominent, actually, but rounded:

attachment.php


attachment.php


The FRs under these three conditions:

attachment.php
 

Attachments

  • OLA XT1086-200.jpg
    OLA XT1086-200.jpg
    63.8 KB · Views: 326
  • OLA XT1086-200 Alone.jpg
    OLA XT1086-200 Alone.jpg
    63.3 KB · Views: 314
  • OLA XT1086-200 Foam.jpg
    OLA XT1086-200 Foam.jpg
    63.5 KB · Views: 314
  • XT1086 Experiment.jpg
    XT1086 Experiment.jpg
    70.7 KB · Views: 520
  • DL2510 DE250 XT1086 Pic.jpg
    DL2510 DE250 XT1086 Pic.jpg
    50 KB · Views: 308
Hello soongsc,

I think you got a shooting star there 😀

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



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



- Elias
Well, we should know pretty soon. The real thing is sitting there waiting to be measured.:yummy:

Would you mind doing some more on simulation impulse data of some configurations I posted in the Geddess web? It's easy for me to re-run the simulations.
 
Last edited:
Can you show the data in a 40db range instead of 25?

and use normalization please too...


Not a lot of work involved -- I'm just clickin' buttons here. 😉

Great button clickin' you are doing here
😀


The wavelets are not normalized; I can do that, but all it does is bump up the falloff at 20 kHz.

There's stuff happening up at 40 - 50 kHz, but that's gotta be aliasing, because the data was acquired at 48 kHz, no?

If so we would be in serious trouble, I guess – but most certainly its just simple cone break up from the compression driver we see here...

🙂

State your hypothesis as to where it is appearing in the wavelet and we'll test that out.

[There's a bigger sandbag, tho.... 😉 ]

Ha ha - the “sandbag” of diffraction alignment
🙂


Michael
 
Last edited:
Ups, run out of time for editing...

The wavelets are not normalized; I can do that, but all it does is bump up the falloff at 20 kHz.

There's stuff happening up at 40 - 50 kHz, but that's gotta be aliasing, because the data was acquired at 48 kHz, no?

If so we would be in serious trouble, I guess – but most certainly its just simple cone break up from the compression driver we see here plus reflections at very short structures from the phase plug

🙂

Remember that in the department of cone breakup not all parts or the diaphragm are excited at the same time – meaning there is time delay involved very similar to reflections.
This is gonna being an interesting field of further research with wavelet analysis besides the quarter wave honk, I'd say...

So – don't cut out this department – we can learn from displaying the “defects” of our speakers happening

Michael
 
Last edited:
By Popular Request:

For starters, you math heads can figure out what's happening up there above 20 kHz; CLIO max sampling rate is 48 kHz for this version:

attachment.php


Here's the three, normalized, to -40 dB:

attachment.php


attachment.php


attachment.php


For fun, open them in separate tabs and click among them.... 😉
 

Attachments

  • OLA XT1086-200N.jpg
    OLA XT1086-200N.jpg
    69.4 KB · Views: 321
  • OLA XT1086-200N Alone.jpg
    OLA XT1086-200N Alone.jpg
    69.1 KB · Views: 320
  • OLA XT1086-200N Foam.jpg
    OLA XT1086-200N Foam.jpg
    69.2 KB · Views: 318
  • OLA XT1086-200 - 100k.jpg
    OLA XT1086-200 - 100k.jpg
    75.7 KB · Views: 312
Last edited:
Hello Zilchlab,

I did some image analysis treatments of your spectrograms.

You'll find in attached files a first image representing the difference between you spectrogram for the first setup (in vicinity of a second enclosure) and the second (alone enclosure).

Then in a second image you'll see the difference between the spectrogram of the foam filled horn and withot (the spectrogram for the"alone" case).

As we can see the presence of a second enclosure or whatever piece of furniture is visible on the spectrogram over 5kHz and for delay above 1,2ms .

We can see also that the foam filling is important over 4kHz and for short delay (less than 2 ms).

An important thing to notice is the removal of some short delays reflections (bright green spots - may be HOMs) for delay less than 0.6ms and frequency over 3kHz (roughly).

Best regards from Paris, France

Jean-Michel Le Cléac'h



Here's the three, normalized, to -40 dB:

IMG]http://www.diyaudio.com/forums/attachment.php?attachmentid=167183&stc=1&d=1271401509[/IMG]
 

Attachments

  • alone-N.gif
    alone-N.gif
    83.5 KB · Views: 163
  • foam-alone.gif
    foam-alone.gif
    73.3 KB · Views: 158
Status
Not open for further replies.