Build your own 2x12" TH (The Kraken 212 TH) - Page 20 - diyAudio
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Old 26th January 2012, 03:25 PM   #191
barco is offline barco  Sweden
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Quote:
Originally Posted by tb46 View Post
Hi barco,

I redrew Petter's exact enclosure in AutoCAD, and remeasured the centerline using soho54's method for the corners. I did not change a thing about the enclosure, but went in the model from 3 horn sections to 4 horn sections.

S1 and S2 remain the same, as does L12. S4 becomes S5, and S3 becomes S4, L34 becomes L45. The former L23 is split into the new L23 and L34, and a new S3 is located in between the new S2 and S4. The location of the new S3 is adjusted to improve the fit between model and drawing.

Even if you're not using Hornresp (yet :-)) you can see at which frequency the response peaks, etc. are supposed to happen.....

Regards,
Could you share the new design? So I understand what the difference is?
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Old 26th January 2012, 03:46 PM   #192
tb46 is offline tb46  United States
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Hi barco,

Post #191: "...share the new design?..."

There is no new design, just an updated Hornesp model as shown in Post #187. For your information I'll attach the drawing from which I gathered the information. Again, the enclosure is not changed.

Regards,
Attached Files
File Type: pdf 3_4_section_dwg_rev.01.pdf (53.6 KB, 149 views)
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Old 26th January 2012, 05:22 PM   #193
barco is offline barco  Sweden
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Quote:
Originally Posted by tb46 View Post
Hi barco,

Post #191: "...share the new design?..."

There is no new design, just an updated Hornesp model as shown in Post #187. For your information I'll attach the drawing from which I gathered the information. Again, the enclosure is not changed.

Regards,
Ahhhhh!! NOW I get it (finally!)

I thought you made some changes to how to build the horn, but it was the hornresp model that you changed to better reflect the measurements I have.

BTW, I have all the material pre-cut in the garage for the next horn so just to get started. Also got the miniDSP today so I guess I will see if I can play around with that and smooth the response of the horn a bit (I am sure I can).
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Old 26th January 2012, 05:28 PM   #194
tb46 is offline tb46  United States
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Hi barco,

Two of those should be enough to "bring down the house". :-)

Regards,
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Old 26th January 2012, 06:27 PM   #195
barco is offline barco  Sweden
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Originally Posted by tb46 View Post
Hi barco,

Two of those should be enough to "bring down the house". :-)

Regards,
Actually, all I am looking for is to make my couch more balanced


Click the image to open in full size.
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Old 26th January 2012, 06:36 PM   #196
barco is offline barco  Sweden
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So I have made some more measurements with open vs "closed" (not really closed, but almost half of the mouth closed).
There is differences, yes. But not that much (at least I dont think so).

First, new measurement "same as before":
Click the image to open in full size.

Second with "closed" mouth. Exactly the same setup with everything else (volume, mic placement etc):
Click the image to open in full size.
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Old 26th January 2012, 06:58 PM   #197
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Cool Looks a little bit better with the mouth partly closed. What's the difference in sound?
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Old 26th January 2012, 07:00 PM   #198
tb46 is offline tb46  United States
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Hi barco,

Your measurements in Post #196 both show a bump in the 30-40Hz region. I get a similar bump in Hornresp when I double the driver impedance (Le). As the driver impedance in the sub 100Hz range is usually not anything like the manufacturer's Le specification (which is normally measured @ 1kHz), a rising Le in this range may be the cause.

At the very low end, below 20Hz it looks like your system may have a low cut filter. Do you have any way of testing for this?

Great couch picture. :-)

Regards,
Attached Images
File Type: jpg JBL_GTO1214_Kraken_212_ACAD_rev.01_4S_SPL_new_Le.jpg (35.8 KB, 306 views)
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Old 26th January 2012, 07:05 PM   #199
barco is offline barco  Sweden
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Quote:
Originally Posted by Petter Persson View Post
Cool Looks a little bit better with the mouth partly closed. What's the difference in sound?
Difference in sound? Does that matter?
I have no clue, have just done the measuring for now.

I am guessing (dont know) but that closing the mouth would affect the "connection" with the room/air but that is just my amateur thoughts...


I connected the minidsp and played for a few minutes (yeah, maybe more) and now I have this graph instead :

Click the image to open in full size.

The minidsp has to be the coolest thing ever....
Added a bandpassfilter (-48db/oct on 10 and 130 Hz) and 5 PEQ points.
Here is the PEQ graph in minidsp:
Click the image to open in full size.

Last edited by barco; 26th January 2012 at 07:13 PM.
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Old 26th January 2012, 07:16 PM   #200
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Quote:
Originally Posted by tb46 View Post
Hi barco,

Your measurements in Post #196 both show a bump in the 30-40Hz region. I get a similar bump in Hornresp when I double the driver impedance (Le). As the driver impedance in the sub 100Hz range is usually not anything like the manufacturer's Le specification (which is normally measured @ 1kHz), a rising Le in this range may be the cause.

At the very low end, below 20Hz it looks like your system may have a low cut filter. Do you have any way of testing for this?

Great couch picture. :-)

Regards,

Oliver, I would rather think the driver motor is not as strong as JBL states
. Try decreasing Bl and keep the horn parameters constant except from the
last segment which is longer in barcos horn then the original Kraken 212.
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