Help understanding sub frequency response info

Ern Dog
Ern Dog Posts: 2,237
edited June 2010 in Subwoofer Hookup & Bass Management
So, I was looking up the frequency response for a JL Audio Fathom F110 sub in their website (here) and found this data but I'm not sure how to interpret it:

27 - 111 Hz (1.5dB)
-3 dB at 25 Hz / 120 Hz
-10 dB at 19 Hz / 155 Hz


Any help would be appreciated. thanks
Post edited by Ern Dog on
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  • thsmith
    thsmith Posts: 6,082
    edited June 2010
    Here is the way I see the data.

    27 - 111 Hz (1.5dB)
    Flat within 1.5db from 27hz to 111hz
    -3 dB at 25 Hz / 120 Hz
    Flat within 3db from 25hz to 120hz
    -10 dB at 19 Hz / 155 Hz
    flat within 10db 19hz to 155hz
    Speakers: SDA-1C (most all the goodies)
    Preamp: Joule Electra LA-150 MKII SE
    Amp: Wright WPA 50-50 EAT KT88s
    Analog: Marantz TT-15S1 MBS Glider SL| Wright WPP100C Amperex BB 6er5 and 7316 & WPM-100 SUT
    Digital: Mac mini 2.3GHz dual-core i5 8g RAM 1.5 TB HDD Music Server Amarra (memory play) - USB - W4S DAC 2
    Cables: Mits S3 IC and Spk cables| PS Audio PCs
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  • Ron Temple
    Ron Temple Posts: 3,212
    edited June 2010
    I wouldn't be concerned about the higher number. To expand on what Tracy said...

    The sub is fairly flat at 27hz, probably starts rolling off around 28-29hz. It's down 3db at 25hz (from 27) and it's down 10db at 19hz (again from 27). That's very good extention for a sealed 10" sub and if you get room/boundary gain, you should be flat into the low 20s, perhaps further.

    Combo rig:

    Onkyo NR1007 pre-pro, Carver TFM 45(fronts), Carver TFM 35 (surrounds)
    SDA 1C, CS400i, SDA 2B
    PB13Ultra RO
    BW Silvers
    Oppo BDP-83SE
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  • Ern Dog
    Ern Dog Posts: 2,237
    edited June 2010
    Cool beans. Thanks for the info Tracy and Ron.

    Now I need to start saving some cash units.
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  • ShinAce
    ShinAce Posts: 1,194
    edited June 2010
    thsmith wrote: »
    Here is the way I see the data.

    27 - 111 Hz (1.5dB)
    Flat within 1.5db from 27hz to 111hz

    -3 dB at 25 Hz / 120 Hz
    -3db @ 25hz and 120hz

    -10 dB at 19 Hz / 155 Hz
    -10db @ 19hz and 155hz

    Fixed! Although the way you wrote it isn't exactly wrong. It should very well be +/-10 dB from 19-155 Hz.

    Sub response is useless unless they state anechoic or in-room. Besides, the room plays such a big part.

    Ron: The room will need to be very small to get cabin gain below 20 Hz.
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