Before Christmas I had been building a test rig. Over the holidays I was sick and without energy to do much and didn't want to leave the house, what better time to run through a bunch of driver tests. I ended up testing everything I had sitting on my shelves, as well as pulled a few drivers that I'm very familiar with as a point of reference.
The Janky Test Rig
I made a platform to easily rotate a speaker at various angles. It's nothing fancy, just a front bearing for a pivot point, and a couple castors on the back to spin around on. It doesn't look like much but works surprisingly well.
The test cabinet is a fairly normal bookshelf size, with removable baffle blanks so I can swap out drivers and test under the same conditions. It's not an IEC baffle by any means, but provides a good point of reference for a somewhat typical use case. The cabinet is sized to accommodate most tweeters, up to 148mm waveguide, and woofers up to 182mm. A solid plant stand elevated the speaker to about the right height for in-room measurements.
Cabinet diffraction response, on-axis for typical 1" tweeter:
Diffraction response in the woofer location, 152mm driver shown.
Equipment
Motu M4
Amp is a LM3886 DIY thing, loopback tested <0.01% THD up to 20kHz.
Mic: Line Audio Omni1
Disclaimer
My setup is NOT SPL calibrated. If SPL is shown in any of the graphs, it is not an accurate figure. Distortion testing was completed at common voltages, distortion measurements are not SPL matched, so take the driver sensitivity into account for comparison. The purpose of this testing was not to replicate any laboratory sort of test results, but to gather enough data to decide the best use case for the drivers I have on the shelf, by observing frequency response and distortion profiles.
The Line Audio Omni1 also is not a "real" measurement mic, however I have found it's response to be within 1dB of my Omnimic, it doesn't have a long stick so there is some early reflection influence in the top end creating some extra wiggles there. Keep that in mind, however there is still plenty of information to determine if the tweeter is problematic or not.
Test Conditions
Frequency response measurements were completed at 1m distance, 15 degree intervals from 0-90 degrees.
Distortion measurements were completed at 315mm distance to reduce room influence, voltage and other conditions as noted.
Driver testing to follow in subsequent posts.
Driver index
Scan-Speak D2604/8330
Vifa D27TG-45
Morel MDT29
Wavecor TW030WA08
Wavecor TW030WA11
Wavecor TW030WA13
Vifa TG9
Melodavid CB25
Peerless 810921
Fountek NeoCD3.0
Dayton PT2C
Peerless 831882
Wavecor WF152BD04
Wavecor WF120BD04
Rival R152PK08
Peerless 2" Dome (model unknown)
AE TD6M
Melodavid BE28
Melodavid D28S
Dayton AMT3-4
Peerless/Vifa DX20FB00
B&W FST LF27715
Melodavid CM25Nd (part 1)
Melodavid CM25Nd (part 2)
SB Satori MW16P-8
Peerless/Vifa/Tymphany NE180W-08
Peerless 830883
The Janky Test Rig
I made a platform to easily rotate a speaker at various angles. It's nothing fancy, just a front bearing for a pivot point, and a couple castors on the back to spin around on. It doesn't look like much but works surprisingly well.
The test cabinet is a fairly normal bookshelf size, with removable baffle blanks so I can swap out drivers and test under the same conditions. It's not an IEC baffle by any means, but provides a good point of reference for a somewhat typical use case. The cabinet is sized to accommodate most tweeters, up to 148mm waveguide, and woofers up to 182mm. A solid plant stand elevated the speaker to about the right height for in-room measurements.
Cabinet diffraction response, on-axis for typical 1" tweeter:
Diffraction response in the woofer location, 152mm driver shown.
Equipment
Motu M4
Amp is a LM3886 DIY thing, loopback tested <0.01% THD up to 20kHz.
Mic: Line Audio Omni1
Disclaimer
My setup is NOT SPL calibrated. If SPL is shown in any of the graphs, it is not an accurate figure. Distortion testing was completed at common voltages, distortion measurements are not SPL matched, so take the driver sensitivity into account for comparison. The purpose of this testing was not to replicate any laboratory sort of test results, but to gather enough data to decide the best use case for the drivers I have on the shelf, by observing frequency response and distortion profiles.
The Line Audio Omni1 also is not a "real" measurement mic, however I have found it's response to be within 1dB of my Omnimic, it doesn't have a long stick so there is some early reflection influence in the top end creating some extra wiggles there. Keep that in mind, however there is still plenty of information to determine if the tweeter is problematic or not.
Test Conditions
Frequency response measurements were completed at 1m distance, 15 degree intervals from 0-90 degrees.
Distortion measurements were completed at 315mm distance to reduce room influence, voltage and other conditions as noted.
Driver testing to follow in subsequent posts.
Driver index
Scan-Speak D2604/8330
Vifa D27TG-45
Morel MDT29
Wavecor TW030WA08
Wavecor TW030WA11
Wavecor TW030WA13
Vifa TG9
Melodavid CB25
Peerless 810921
Fountek NeoCD3.0
Dayton PT2C
Peerless 831882
Wavecor WF152BD04
Wavecor WF120BD04
Rival R152PK08
Peerless 2" Dome (model unknown)
AE TD6M
Melodavid BE28
Melodavid D28S
Dayton AMT3-4
Peerless/Vifa DX20FB00
B&W FST LF27715
Melodavid CM25Nd (part 1)
Melodavid CM25Nd (part 2)
SB Satori MW16P-8
Peerless/Vifa/Tymphany NE180W-08
Peerless 830883
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