S18 : 2-way 8" DSP Waveguide Controlled Directivity Loudspeakers

This is probably the best price-performance DSP speakers I have ever built. Unlike the 12" econowave project which had questionable midrange, these speakers equals much more complex and expensive ones and in some aspects like vocals are more effortless. The 40hz bass is honest and very deep. Sure you do not have that spacious sounds Dipoles project but that's not entirely a bad thing.

Waveguide: FaitalPro STH100
Compression driver: B&C DE250
Woofers: FaitalPro 8PR155
XO: 1.5kHz LR4
Low freq: -6dB at 40Hz

Note: FaitalPro 8PR200 has more excursion butI prioritise midrange quality. The 8PR155 is 1khz further in the upper frequencies before breakups.

SETTINGS:

Tweeters/Compression drivers
Attenuation: L-PAD to reduce hiss of this high sensitivity driver

XO : 1.5khz LR4
Notch 1: 3916 hz/ -4db / 1Q
Notch 2: 16273 hz / -4db /5Q
It is very rare to see electrical slope = acoustic slope so I am very happy. The ±1db of STH100 and DE250 is impressive.

Woofers
Attenuation -3dB (yes you can modify the above tweeters' LPAD so this become 0dB but then you might hear hiss more)
XO: 1.5kHZ LR4
Baffle step (optional): 90hz / -5db / 1Q shelving low-pass
I equalise the system for -6dB at 40hz with Q=0.707 (basically a 40hz highpass LR4)
To do this we need 2 Linkwitz Transform (LT) biquads.
(warning these values only applies if your DSP is 96khz like miniDSP)

First biquad:
biquad1,
b0=1.00515510631325,
b1=-1.99721101580319,
b2=0.992083287073699,
a1=1.99722277960871,
a2=-0.997226629581425

Second biquad:
biquad1,
b0=0.998612353349429,
b1=-1.99722470669886,
b2=0.998612353349429,
a1=1.99722278171542,
a2=-0.997226631682297

Measured nearfield we can see the original frequency response in yellow and equalised in green.