These measurements were all taken using my large, flat baffle. The drivers were all flush-mounted and located equi-distant from each side of the narrow dimension. The distance in all cases is measured to the baffle surface. The start time marker was set to the same value for all, set so that it was placed near the earliest noticeable signal input from the microphone (not the impulse peak nor just prior to it), since this has an effect on the high frequency result in the FFT (too close to the impulse peak and there is some false upper end rolloff/non-linearity).

The system used to measure includes:

• Software - Liberty Audiosuite (LAUD)
• Fiji Sound Card
• Calibrated Panasonic microphone (from Kim Girardin) in a custom wand
• Camera tripod used as a microphone stand
• 4' by 7' (or 2m by 2m) MDF Baffle 3/4" thick with a 12" by 24" baffle insert (braced)

Software settings:

• 4,096 point MLS
• 16,384 point FFT
• Half Blackman-Harris Window

The primary SPL measurements were taken at 0.5m on the driver axis. Note that these results include a fair amount of excess-phase which I cannot remove with any accuracy since the absolute acoustic center is as yet an unknown value for any driver.

Note that there is no smoothing applied to these curves. All files for download were taken on my "quasi-IEC" baffle, 4ft x 7ft, or the newer one with extension that make it 2m x 2m.

Keep in mind that the driver position on a regular baffle will have an impact on the response, since for tweeters there will be baffle step and significant diffraction effects.

	Vifa XT19 SPL XT19 Z Thanks to Mark Krawiec
	Hiquphon OW1 SPL OW1 Z
	Scan-Speak D2010/8513 SPL D2010/8513 Z
	Hiquphon/Scan-Speak Hybrid Hiquphon Motor Assemby and Case Scan-Speak D2010/8513 Diaphragm Assembly
	Vifa XT25 SPL XT25 Z
	Scan-Speak D2905/9300 SPL D2905/9300 Z
	Scan-Speak D2905/9500 SPL D2905/9500 Z
	Seas T25-002 SPL T25-002 Z
	Dayton Reference Series Tweeter RS28A-4 SPL RS28A-4 Z
	Seas 27TDFC SPL * 27TDFC Z Thanks to Mark Krawiec
	Seas 27TDC SPL * 27TDFC Z Thanks to Mark Krawiec
	Vifa PL27TG-35 SPL * PL27TG-35 Z Unmodified Thanks to Doug Packard
	Dayton/Morel Hybrid I SPL Dayton Gen 2 Motor (w/Cap) MDT-30s Dome Assembly Lamb's Wool Mod
	Dayton/Morel Hybrid II SPL Dayton Gen 1 Motor (no Cap) MDT-30s Dome Assembly Lamb's Wool Mod
	Dayton "Silkie" D275-070 SPL D275-070 Z Gen I Lamb's Wool Mod
	Dayton "Silkie" DC28F SPL Gen IV Lamb's Wool Mod Thanks to Shawn A
	Morel MDT-30 SPL NOTE: Not the "S" version Lamb's Wool Mod
	Morel MDT-20 SPL MDT-20 Z Lamb's Wool Mod
	Vifa DX25 SPL *
	Vifa DX25 Lamb's Wool Mod
	Vifa DX19 SPL * DX19 Z Thanks to John Krutke