ZD5 impedance curve mismatch

zdr · 09:56 PM

I've just setup my measurement jig for LIMP, so I gave it a go on ZD5. What came out is a huge mismatch in bottom end impedance curve. Could stuffing be causing this, since I double checked the crossover and imaging is spot on?

Flaesh · 10:10 PM

Quote:

Originally Posted by zdr

.. Could stuffing be causing this,..

(yellow curve with more mechanical loss)

zdr · 21st September 2010, 09:44 AM

Hm, should I be bothered with this? I managed to align the peaks by adding more stuffing into the box that was missing it, and now they are both the same inside out. Peaks are still much higher on one than on the other.

zdr · 21st September 2010, 08:28 PM

Erm, yes I should. There is audible difference between the two. The higher peak sounds brighter, pulling the image to the side. I just wonder what could be the problem... I am tripplechecking the stuffing and mechanics.

Flaesh · 21st September 2010, 08:39 PM

are drivers themself (w\o enclosure) identical?
are speakers w\o stuffing identical?

sreten · 21st September 2010, 08:46 PM

Hi, test the raw bass/mid drivers in free air, rgds, sreten.

zdr · 10:55 PM

Yep, just did, and switched drivers. Problem stays with the box... Stuffing is approximately the same, I will make it identical tomorrow.

zdr · 26th September 2010, 09:07 AM

Huh, I am really scratching my head on this one. Boxes and stuffing are now identical, and I still have a peak height mismatch. I even scalloped some more around the driver.

The one with higher peak definitely sounds more open and detailed. I am about to redo the crossover so that I can switch them between the boxes, to narrow down to box or crossover.

I don't know if it makes sense to switch XT25s...

Flaesh · 26th September 2010, 09:20 AM

can you definetly eliminate any leakage? gap between panels??

zdr · 26th September 2010, 04:20 PM

Yep, that was it. I made a test with rear panels removed, and curves aligned. It was a gap between removable rear panel and the box, caused by tiny dry paint drops.

21st September 2010, 08:39 PM	#5
Flaesh diyAudio Member Join Date: Dec 2009 Location: Eburg	are drivers themself (w\o enclosure) identical? are speakers w\o stuffing identical? __________________ flesh flash flush

21st September 2010, 10:35 PM	#7
zdr diyAudio Member Join Date: Nov 2005 Location: Brussels	Yep, just did, and switched drivers. Problem stays with the box... Stuffing is approximately the same, I will make it identical tomorrow. Last edited by zdr; 21st September 2010 at 10:55 PM.

26th September 2010, 09:20 AM	#9
Flaesh diyAudio Member Join Date: Dec 2009 Location: Eburg	can you definetly eliminate any leakage? gap between panels?? __________________ flesh flash flush

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21st September 2010, 09:44 AM	#3
zdr diyAudio Member Join Date: Nov 2005 Location: Brussels	Hm, should I be bothered with this? I managed to align the peaks by adding more stuffing into the box that was missing it, and now they are both the same inside out. Peaks are still much higher on one than on the other.

21st September 2010, 08:46 PM	#6
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, test the raw bass/mid drivers in free air, rgds, sreten.

26th September 2010, 09:07 AM	#8
zdr diyAudio Member Join Date: Nov 2005 Location: Brussels	Huh, I am really scratching my head on this one. Boxes and stuffing are now identical, and I still have a peak height mismatch. I even scalloped some more around the driver. The one with higher peak definitely sounds more open and detailed. I am about to redo the crossover so that I can switch them between the boxes, to narrow down to box or crossover. I don't know if it makes sense to switch XT25s...

26th September 2010, 04:20 PM	#10
zdr diyAudio Member Join Date: Nov 2005 Location: Brussels	Yep, that was it. I made a test with rear panels removed, and curves aligned. It was a gap between removable rear panel and the box, caused by tiny dry paint drops.

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