Need a subwoofer for FR10 bookshelves.

[50AE]

I've been offered for very cheap small bookshelves fullrange speakers with Visation FR10 8 ohm drivers. Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

Of course, they struggle on the lows, so I'd like to build a subwoofer for them. My questions are:
-What should be cut off frequency?
-What should be the order of both of the crossovers?
-What should be the nominal power and sensitivity compared to the drivers - subwoofer to satellite ratio?
-Because of availability, I'd like to use a visaton speaker. Can you recommend me one?

The crossover of the sub could be made active with a variable cut off frequency, in case I get a bad frequency response.

[bjorno]

Originally Posted by 50AE

I've been offered for very cheap small bookshelves fullrange speakers with Visation FR10 8 ohm drivers. Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

Of course, they struggle on the lows, so I'd like to build a subwoofer for them. My questions are:
-What should be cut off frequency?
-What should be the order of both of the crossovers?
-What should be the nominal power and sensitivity compared to the drivers - subwoofer to satellite ratio?
-Because of availability, I'd like to use a visaton speaker. Can you recommend me one?

The crossover of the sub could be made active with a variable cut off frequency, in case I get a bad frequency response.

Hi,

Why not build a low footprint sub using the 8” Visaton AL 200 driver using a ported design.

IMO, best SQ if converting the most promising box(70L BR) recommended by the manufacturer to a T-TQWP.

My suggestions are: XO somewhere between 120-145 Hz using a 24 dB LP filter for the sub and for the FR 10 use a 12dB HP filter.

When placing the sub somewhere at 1 - 0.5Pi space angle: One Visaton AL 200 driver in a T-QWP will match the two FR 10:s sensitivity well.

b

[tb46]

Hi bjorno,

Interesting design. You may want to check, but I think in your drawing you swapped the S1 and S4 designations.

Regards,

[bjorno]

Originally Posted by tb46

..I think in your drawing you swapped the S1 and S4 designations..

Thanks tb46, for being observant!

Agree, You're right, In the picture S1 and S4 should be swapped

b

PS: The driver offset distance is not correctly predicted in HR as the crude picture is depicting but this discrepancy is IME of minor importance...obvious noticed if simulated in MJK:s program using appropriate amount of damping material.