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Old 2nd August 2011, 07:33 PM   #2071
Kolbrek is offline Kolbrek  Norway
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Quote:
Originally Posted by mwmkravchenko View Post
Measurement specialties make some pretty inexpensive pressure transducers. They have to be able to measure very low pressures actually. And I am putting together an accelerometer to make insitu X-max measurements.
Why don't you want to use microphones to measure pressure? If you use a pressure sensor, make sure it can measure the actual variation of pressure, and with a good enough BW and SNR, because it looks like many of the pressure sensors are made for measuring static pressure. (If you want to measure the distortion, SNR is quite important. The M52 mic needs > 120dB SPL to measure distortion realiably).

I have used an accelerometer from Measurement Specialities, the ACH-01 to measure diaphragm displacement, it works well. I found it was most stable to integrate (twice) from acceleration to displacement in SW, by first getting the acceleration frequency response, and then multiply twice by j*omega to get displacement.

Good luck.

Bjørn
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Old 3rd August 2011, 01:21 AM   #2072
Mark Kravchenko --- www.kravchenko-audio.com
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I am going to use the G. Danavaras amplifier with the built in integrator. Easier than fooling around other ways. He's a smart guy no use me trying to improve on that design. Only wish I could find a PCB pattern.

Maybe I should get that crazy microphone.

Not cheap to be sure.

I have read some good things about the Linkwitz modification on the Panasonic cartridges. Just not sure if they will survive the high SPL at the throat.

Because you are correct Bjørn a pressure transducer will not read the transients. At least not the ones I will be able to afford.
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Old 3rd August 2011, 04:29 AM   #2073
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Mr. McBean,

Thank you so much for the update and all of the new features.
I love the new mouseover crosshair cursor for sampling the values on the new graphs. Is there any chance this feature could be carried over to the existing graphs? It is much faster than keying in frequencies.

I've not found any issues or compatibility problems with the latest version. Thanks again for such a great piece of software.
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Old 3rd August 2011, 04:31 AM   #2074
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Quote:
Originally Posted by mwmkravchenko View Post
.....
I have read some good things about the Linkwitz modification on the Panasonic cartridges. Just not sure if they will survive the high SPL at the throat.
......
With the Linkwitz-modded mics, distortion becomes an issue above 130 dB. Not sure when the capsule fails, haven't built a sub that loud (yet...).
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Old 3rd August 2011, 11:32 AM   #2075
Mark Kravchenko --- www.kravchenko-audio.com
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Quote:
With the Linkwitz-modded mics, distortion becomes an issue above 130 dB. Not sure when the capsule fails, haven't built a sub that loud (yet...).
Near the throat it will be much in excess of 130 db.

I have been doing some reading on changing the polarizing voltage. And I still have to find the cost on those piezo film type mics. Maybe a poor man can do some fancy measurements after all.

And what do you mean not built a sub that can do 130db!

Man!

NO Problemo

What I have to say is that using the new tools on some of my older designs I am intrigued by the results. The best performers are rather well balanced. In terms of pressure modulation and particle velocity. Things I always knew were important but had to more or less use "seat of the pants type engineering". The kind where you just know what will or will not perform. I guess that is born from doing this stuff for a long time. I had hair when I started working on horns. To much testing blew it all away. That's my story and I'm sticking to it!

Now I have a few tools that will get me much closer to knowing what will perform.

Now to quantify a few of these calculations and things will get a lot more interesting.
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Old 3rd August 2011, 08:23 PM   #2076
NEO Dan is offline NEO Dan  United States
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Loving the new features in v28.6, very cool stuff! Like Mark I've been going back through my database, it's been quite insightful.

Thanks David
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Old 3rd August 2011, 10:29 PM   #2077
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Quote:
Originally Posted by mwmkravchenko View Post
... I had hair when I started working on horns. To much testing blew it all away. That's my story and I'm sticking to it!
Thinking about horns generates heat. The heat kills the hair follicles. It's not all bad though, the heat then radiates away more efficiently and you can think even harder. That's *my* story and I'm sticking to it.
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Old 4th August 2011, 07:30 AM   #2078
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Originally Posted by littlemike View Post
I love the new mouseover crosshair cursor for sampling the values on the new graphs. Is there any chance this feature could be carried over to the existing graphs?
Hi littlemike,

I will see what I can do - the cursor pointer will remain as the default shape, though.

It may take me a day or so...

Kind regards,

David
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Old 5th August 2011, 04:14 AM   #2079
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Originally Posted by David McBean View Post
Hi littlemike,

I will see what I can do - the cursor pointer will remain as the default shape, though.

It may take me a day or so...

Kind regards,

David
Thank you very much!
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Old 5th August 2011, 04:21 AM   #2080
NEO Dan is offline NEO Dan  United States
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Hi David,
Would it be possible for Hornresp to not automatically move the driver from S3 to S4 on a 5 segment TH?
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