Lark DCR2 (Dual Chamber Reflex)
SB Acoustics SB16PFC25-8 with Dayton ND25FW-4
In this next version, I’m pairing the SB16PFC25-8 with a mini Waveguide tweeter by Dayton, the ND25FW-4. I am keeping an open mind with this ND25FW-4 as this is my first time listening it.
As before, the speaker is actively bi-amped. A 24dB/oct Linkwitz Riley electronic crossover is set for 3kHz for all measurements. Microphone is at 36 ins, tweeter axis. Impulse Window = 5msec. No Smoothing applied. Frequencies below 500Hz are in Nearfield.
RAW Frequency Response of SB16PFC25-8
DCR Box = 40 liters. Baffle Width = 9″
Fig 1 – Measurements below 500Hz are in Nearfield.
Crossing the SB Acoustics SB16PFC25-8 with Dayton ND25FW-4
fc = 3kHz • 24dB/oct • Linkwitz Riley
Fig 2 – Blue plot = SB16PFC25-8. Red plot = ND25FW-4.
Summed Response of SB Acoustics SB16PFC25-8 with Dayton ND25FW-4
Fig 3 – Summed Response with ND25FW-4 wired in Normal Phase
DCR2 Top and Bottom Port Frequency Response
Fig 4 – Blue plot = Top port. Green plot = Bottom port.
Lark DCR2 Cumulative Spectral Decay (CSD)
Fig 5 – Rise Time = 0.10 msec. Window = 1.3 msec ( 769Hz ). Time Range = 1.5 msec
Lark DCR2 Toneburst Energy StorageFig 6 – SB16PFC25-8 with ND25FW-4. Crossover 3kHz.
Lark DCR2 SpectrogramFig 7 – SB16PFC25-8 with ND25FW-4. Crossover 3kHz.
Lark DCR2 Step ResponseFig 8 – SB16PFC25-8 with ND25FW-4. Crossover 3kHz.
Harmonic Distortion of Lark DCR2Fig 9 – Red plot = 2nd Harmonic. Violet plot = 3rd Harmonic.
How’s the Sound?
The Dayton ND25FW-4 tweeter is amazing. It beats the Goldwood GT-520 hands down. Though it is not as flat as the GT-520, it extends to 20kHz. Because of that, the highs in the ND25FW-4 sound much richer. To get a similar effect, the GT-520 will need to be supported by a super tweeter.
Apart from the improved treble, the midrange and bass remain the same as in the Lark DCR. Vocals are slightly forward and transparent, exhibiting no veil in the midrange. Upper and lower bass are clear, distinct and dynamic. Listening to the bass of UFO Tofu from Bela Fleck and the Flecktones was a delight. Not many speakers are capable of reproducing bass faithfully from UFO.
The ND25FW-4 cost only $18.45 at Parts Express but performs like a tweeter costing many times more. The most important aspect of the ND25FW-4 is the waveguide. It completely avoided the nasty front panel diffraction that plagues all conventional dome tweeters sporting a flat face plate.
The Lark DCR2 deserves a passive crossover. She is really affordable yet sounds excellent. My kind of speakers.