HOLMImpulse: Measurements in practice

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#282
panomaniac said:
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?
Click to expand...

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
 
#283
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
 

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#284
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.



speakerdoctor said:
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?
Click to expand...
 

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#294
"Search this thread" feature is handy.

As I said, a Dayton or Behringer measurement mic (see Parts Express) and a USB soundcard with phantom power. Easy! Look at M-Audio for the soundcard. Used on eBay everyday, too. Get you a boom type mic stand and some XLR cable and you're good to go.

It's easy, really.
 
#295
panomaniac said:
"Search this thread" feature is handy.

As I said, a Dayton or Behringer measurement mic (see Parts Express) and a USB soundcard with phantom power. Easy! Look at M-Audio for the soundcard. Used on eBay everyday, too. Get you a boom type mic stand and some XLR cable and you're good to go.

It's easy, really.
Click to expand...

Well that's debateable , Don't you think !

If your new and there are problems you need the troubleshooting skills or you will be wasting your money !!

And beleive me they can be tough to pin down !!
 
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