HOLMImpulse: Measurements in practice

[Pano]

It's easy to try, right? Don't you have a spare 8R and 10uF or similar lying around?

[LineArray]

Originally Posted by panomaniac

Hi Oliver. Nice finds on the software. I've only seen one of those before.
But after looking at so many, I just use ARTA. It does the waterfalls and spectrograms just fine. You've tried it, I suppose?

Glad you fixed your plot! That big rise in the THD had me worried. Is this an NXT type panel? Balsa wood?

Yes i have seen ARTA CSDs, they are fine indeed.


It is a new type of bending wave transducer. Manufacturers of bending
wave transducers would surely be glad to have something which comes
even close.

And they would surely be glad if they knew how to achieve the
properties.

Several materials are posible, but its too early now for details ...
It was just "the current speaker under test".

Kind Regards

[LineArray]

Attached graph shows some speakers in the same room but
different positions. Positions and room are both suboptimal.

RED:
Bookshelf Speaker with ribbon tweeter, measured slightly
below the tweeter axis, should better be above.
Free standing, needs closer rear wall or bookshelf,
too less bass in that position.

BLUE:
Bending Wave Transducer
Side wall too near.

GREEN:
Dipol 08 Line Array
Mike sould be somewhat higher on ear height.
Rear / side wall is too near.
No subwoofer, 1 satellite only.

But nevertheless:

The Bending Wave Transducer has lowest bass extension,
smoothest phase rotation, lowest distorsion and the smoothness
of FR is at least on the same level with the "conventional colleagues".

The top end roll off can be fixed easily like mentioned before.
Not to mention is has the smoothest dispersion in the highs.


Kind Regards

[speakerdoctor]

Attached is the test I promised in another thread showing the 400 hz phase inversion.

Also, is the impulse response acceptable? I'm not sure what's good and not good on this measurement parameter.

Originally Posted by speakerdoctor

Recently conducted some HI tests starting to use the software and discovered a phase inversion within my 2-way woofer's passband at around 400 hz.
I'm running the test in a 13 sq. ft room with the speaker oriented diagonally corner-to-corner to minimize reflection/mode effects. The speaker has a 2nd order LP and a 3rd order HP with conventional topology.

I wonder if the 400 hz phase inversion is being caused by acoustic effects such as a room mode or diffraction. The other phase inversion is at the expected crossover point of about 2200 hz.

Any ideas as to the cause?

[jtwrace]

Is there a manual for use? Is this software easy to use compared to REW? REW seems to be a pain with calibration of the soundcard....

Any info is greatly appreciated.

[Pano]

There is a PDF users guide on the website - I think.

[jtwrace]

Originally Posted by panomaniac

There is a PDF users guide on the website - I think.

Yes, but there seem to be directions of how to setup and use.

[jtwrace]

I need to be clearer. Sorry.

No directions with setup of mic and soundcard. Useable mics and soundcards. Can I use a R.S. meter?

[Pano]

Doesn't this - http://www.holmacoustics.com/downloa...eUserGuide.pdf tell you what you need to know?

[Pano]

Oh, OK. You "can" use a Radio Shack meter, but it's not a great idea. Better to get one of the Dayton or Behringer calibrated mics. A USB soundcard with phantom power will set you up to go.