Vifa M25WO49-08 10″ Woofer
I have this vintage, made in Denmark, 10″ Classic Vifa woofer in storage for almost 20 years. In all these years, I never got the chance to listen to it. Now that I’m all setup for testing 10″ woofers, I thought, why not, let’s see how well this 10″ fares in a 2-way.
Vifa M25WO49-08 Frequency Response
Fig 1 – Manufacturer’s Frequency Response
Measured Vifa M25WO49-08 Frequency Response
Ported Box = 55 liters. Baffle Width = 16insFig 2 – Black Plot = RAW, Blue Plot = 1.5kHz (24dB/oct, Linkwitz Riley)
My frequency sweep (Fig 2) of the M25WO49-08 is remarkably similar to Vifa’s (Fig 1). A dip is recorded at 500Hz, exactly what is shown in Vifa’s response. I would normally avoid this dip and cross the woofer at least one octave lower but for this 2-way project, I’ll ignore it and cross it higher. The Blue plot is with my external crossover set at 1.5kHz (24dB/oct – Linkwitz Riley). The roll-off is beautiful. No sharp peaks anywhere.
Ported Box Alignment
Fig 3 – Ported Box Simulation of Vifa M25WO49-08
I loaded the M25WO49-08 onto a ported box of 55 liters tuned to 35Hz (Fig 3). This is out of convenience because my test box is available. The bass should sound fine with a System Q of 0.64. If I want to go deeper in future, I can always load the M25WO49-08 onto a larger 80 liters enclosure.
Crossing the Vifa M25WO49-08 with Pyle PDS442+Dayton H07E
Fig 4 – Blue plot = DA270-8, Red plot = Pyle PDS442+Dayton H07E
The Red plot (Fig 4) is of the Pyle PDS442+Dayton H07E at 1.5kHz (24dB/oct, Linkwitz Riley). The two drivers cross acoustically at about 1.4kHz which is close to 1.5kHz on my external active crossover.
Summed Response of Vifa M25WO49-08 with Pyle PDS442+Dayton H07E
Fig 5 – Summed Response with Pyle PDS442+H07E wired in Reversed Phase.
Fig 5 is the Summed Response of the Vifa M25WO49-08 with the Pyle PDS442/H07E combo. It is virtually flat from 600Hz to 7.5kHz. The Pyle PDS442 is wired in reversed phase for proper summing.
Summed Response with Crossover Null
Fig 6 – Summed Response with Pyle PDS442+H07E wired in Normal Phase.
Fig 6 is the Summed Response with the PDS442 wired in Normal Phase. A null is visible at about 1.4kHz, which is where the two drivers crossed acoustically (Fig 4). The null is not as deep as I would like but for the time being, it’s good enough.
Harmonic Distortion of the Vifa M25WO49-08 with Pyle PDS442+Dayton H07E
Fig 7 – Distortion Sweep with Mic at 24 ins.
The 2nd (Red) and 3rd (Violet) harmonic distortion of the Vifa M25WO49-08 with the Pyle PDS442/H07E average about -55dB below the fundamental at 1kHz upwards. Disregard the measurements below 1kHz as they are inaccurate.
Toneburst Energy Storage of Vifa M25WO49-08 with Pyle PDS442+Dayton H07E