NextWaveSS

Large floorstanding 3-way loudspeaker TMWW 1"+6"+8"+8"

Drivers: Wavecor WF223BD02, Seas W18NX001, Scan Speak R3004/6620+ WG148R
Dimensions: H 1160 x W 280 x D 400 mm
Sensitivity: ~90dB/2.83V/1m
Impedance: 4Ohm nominal, 2.9Ohm minimum at ~30Hz
Crossover: all LR2, 300Hz, 2200Hz 

I was asked by friend of mine to come with the project of the larger 3way, based on R300/6620 and W18NX which he had already at home. It did not take me much thinking to figure out project would have waveguide and two 8inch woofers for higher sensitivity. 

I decided on WG148R, which are not the best match for ringradiator, one can do better with custom WG, but I wanted to avoid any complications with cnc or 3D printing and surface finish. WG148 proved to work very well here, it created mild boost of frequency response around 2-3kHz, and still maintained smooth overall response upto 20kHz. Also diffractions were mitigated by WG, in addition to R30 roundovers of the baffle. This is good material for easy crossover work.

I knew W18NX from one of the earlier 2-way project. Very nice and smooth midrange, but little bit weaker on bass, so using this midwoofer as midrange seems to be the best implementation of this driver.  

WF223BD02 looked very good in datasheet, Basta modelling showed 2 in parallel would work well in 75l volume BR cabinet. They are also good visual match for Nextel mid. 400Hz dip is little bit dissappointing, so far I haven't found the root cause of that, it seems either inherent to the driver, though there are no signs of impedance problems in measured free-air impedance, or measurement artefact. Besides that, it measures very nice, with smooth and extended FR, free of any breakups that would need extra attention in the crossover.   

I had very high hopes for WF223, and was not disappointed. F-3 is 37Hz, F-6 31Hz, this loudspeaker can go deep with ease and lightness, and bass is well integrated with the rest.

W18 Nextel as midrange is.....neutral. I was thinking a long time how to characterize its sound, and I cannot come to a specific word or characteristics. It just sound neutral, normal, does not attract attention, is very well sonically in accordance with the rest, it just seems to have all that should be there in the balance. It does not have the warmth of Revelators, detail, transparency and sparkle of Illuminators, and thinking of it, the midrange seems sonically close to Satori MW16 and MW19, though Satoris are cleaner.

Drivers measurement

Drivers responses measured from 1m distance, gatting 4,2ms for tweeter and midrange, 10ms for woofers (shorter window was tried to observe impact on 400Hz dip). Woofers were connected in parallel and mic placed right in between of them.

R3004+WG  horizontal FRs 0-90deg

This is actually better than I expected, and this response is very easy to work with. One has to be really carefull to seal all potential air leaks on those Illuminator tweeters to get clean and healthy impedance profile.

W18NX  horizontal FRs 0-90deg

I knew W18Nextel from earlier construction and measurements, and I was very pleased again to see those measurements.

WF223  horizontal FRs 0-90deg 

The dip at 400Hz was explored, it is not caused by port nor any resonance in the cabinets. Impedance measurement does not suggest any problem in that area either. Also 400Hz sinewave from generator did not reveal any audible resonance, drivers were driven to quite upleasant SPL.

More on WF223BD: Measured impedances of 4 samples are below, free air, no burn in. Measured Fs are 35.5, 36.3, 36.4, 36.7 Hz. This is already good match to 33Hz Fs in datasheet and nice consistency within the group.

Zoomed impedance profile does not suggest any problems in 400Hz area.

Crossover design

Depth of WG148 is 20mm, I hoped it would be enough to allow for LR2 between tweeter and midrange. This proved to be true, though 30mm WG depth would be optimal.

This is the final version. I was surprised, as it was quite fast and easy to arrive to this version and sound, which is not always the case. Also note excellent phase tracking all the way from the woofers to the tweeter. 

Crossover is what I expected, and all drivers were very easy to work with.

Horizontal directivity, normalized. The influence and benefit of the waveguide is clear.

Spinorama curves, all are very smooth, promising easy integration in the listening room.

Photos

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