# Advice for horn design for 2x8" drivers



## dodrive (Mar 3, 2021)

Hello everyone.
I have 2 spare 8 inch woofers that unfortunately didn't fit in my doors and I was toying with the idea of creating a horn loaded sub with them.

These are their T/S parameters:
Overall diameter: 215mm (8.5-inch)
Mounting depth: 92mm
Bolt Circle Diameter: 195mm
Mounting hole: 185mm
Pnom (without crossover) 75W (AES Standard)
Pmax (without crossover): 150W
Pmax (with recommended crossover): 250W
Frequency range: 40Hz – 2,000 Hz
Sensitivity: 87dB (2.83V/1m)
Mms: 31.5g
Cms: 454 um/N
BL: 5.99 T*m
Voice coil diameter: 35.55mm (1.4-inch)
Impedance: 4 Ohm
DC Resistance: 3.4 Ohm
Fs: 40Hz (free air)
Qms: 7.35
Qes: 0.693
Qts: 0.765
Xmax: 8.5mm (one way)
Vas: 26L
Sd: 0.02 m2

Any feedback on the feasibility of this idea from someone more experienced than me would be greatly appreciated because I feel like I'm over my head in this... From what I gather the Qts might be on the high side since they were designed as IB speakers to work their best in the usual door-mounted situations, but I was hoping that maybe they could be put to good use as a sub with some creative loading solution. The setup is SQ oriented, FWIW.


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## oabeieo (Feb 22, 2015)

Decware has the wikked one and the plans online 

i have built 3 of them and they are ohhh lala


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## Patrick Bateman (Sep 11, 2006)

I've built a few horn loaded subs for the car, but largely gave up on the idea. Basically most of the "gain" that you get is above 40Hz.

For instance, if you have a front loaded horn with an F3 of 35Hz, the subwoofer may be as much as 6-12dB more efficient than a sealed box *but only above 40Hz.* That type of set up is great for a nightclub, where you want that "kick" in your chest that you get with a 60Hz bass guitar note.

But in a car? It's trivially easy to generate a lot of output between 40-80Hz, due to cabin gain.

And worst of all, BELOW 40Hz that horn sub will be about as efficient as a plain ol' sealed sub.


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