[rhodesj]

I want to take some measurements of my sealed 1260ws with different amounts of stuffing. Is there any drawback to doing so close-mic'd in the house, as opposed to in the middle of my driveway? It'd be easier not weighing Polyfill in the yard, and with a sealed sub I don't have to worry about measuring the port and driver separately.

 

[tuxedocivic]

I think it would be fine but difficult to repeat at that distance. Perhaps 6" would be nearfield enough to see the differences but not so close that 1/8" matters.

 

[BassThatHz]

Driveway would be better, but close mic is "good-enough".

Stuffing won't really change the response much; a few db this way or that. The waterfall chart would probably show the largest difference.

 

[Jay1]

Nearfield on a 12" woofer should be done at approximately 0.525" (mic centered on woofer). This will produce an accurate frequency response measurement from approximately 10 - 410 hz.

There's a pretty good chance you wont have a "clean" enough driveway and surrounding area for an accurate groundplane measurement. Most people dont. The only reason really to do groundplane is for accurate max spl measurements.

 

[Bill Fitzmaurice]

Where to measure depends on your intent. Nearfield is fine for comparison purposes, in room is best for eqing to the room and finding the best placement, outdoors groundplane is for when you want a true half-space result.

 

[rhodesj]

My basic intention is just to gather some data on fine tuning the stuffing. Take FR sweeps and impedance sweeps with different amounts of polyfill, see how response changes, maybe see if I can figure how Q changes for the sub, maybe even equate that back to the Qa parameter in WinISD.

Seems like inside will be fine, just have to make sure I can keep the mic setup repeatable.

 

[LTD02]

josh has an a-b comparo measured on data-bass on stuffing if you haven't already seen that one, might be worth a read.