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Usable low frequency

Discussion in 'Amps and Cabs [BG]' started by Cristo, Nov 15, 2005.


  1. I've been poking aroung looking at info on various cabs. I came across specs for the Ampeg SVT-410HE. The "usable low frequency" is quoted as 43 Hz.

    What exactly does this mean to anyone? My understanding was that it was the lowest frequency the cab was able to reproduce. Now I'm thinking perhaps I'm wrong about that...

    Wouldn't that be a bit of a problem for a bass cab, since the low E on a 4 string is 41 Hz? What good is a cab that can't handle the lowest note of a standard bass?
     
  2. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The -3 dB frequency is shown as 62 Hz.... the lower "usable" frequency is the lowest at which you can get reasonable output without getting into speaker-stressing conditions, like over-excursion of cones, having to boost volume past the safe power limits, etc.

    Not at all. Some of the most popular cabinets are nearly identical in response to that. The usual sealed 810 starts to roll off at 60 hz or so.

    So much of the energy in the note is in the harmonics that the fundamental is not that important.

    In fact, if you want a recipe for muddy sound and wimpy power output, its really easy. Just boost the fundamentals with the EQ until you start to feel them in your feet......

    You'll use up most of your power on low end, doing nothing much but shaking the stage. There will be little left for projecting actual tone and articulation.........

    Oh, and the sound man will probably hate you for putting all that mud in the mics, too......
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Good question. You'll get different answers from the marketing and engineering departments. Amongst engineers a generally accepted figure is down 10dB. In the marketing department it could mean down 30dB. Finding out for sure is usually as fruitless a quest as waiting for Godot.
     
  4. Doug Parent

    Doug Parent Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    Well said Bill. Listen with your ears I guess still has some workability eh?
     
  5. So, if I interpret correctly -

    lowest usable frequency is the point beyond which frequency response is rolled off too much to be "useful" - which is somewhat arbitrary, but maybe around -10dB.


    Thanks for the response from those in the know about speakers and cabs.
     
  6. As soon as I started using cabinets that put out anything below 50Hz is when I started using filters to keep that signal from ever reaching the amp. Believe me that cab you are looking at goes LOW.
     
  7. WalterBush

    WalterBush

    Feb 27, 2005
    Yuma, Az
    Correct me if I'm wrong, but wasn't the original Ampeg 810 tuned to avoid the fundamentals, and push the harmonics so as to be louder? Mine works great with a 4-banger, but loses some significant push when trying to reproduce a low B.
     
  8. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    That's about right according to how it works, and agrees with my understanding of the design intent.
     
  9. Godot said he would stop by. He owes me money. Are you calling Godot a liar????

    Randy
     
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    That applies not only to cabinetry but also the drivers within. Almost every pro-sound woofer sacrifices low frequency response for the sake of efficiency, and to a great extent the tone of the electric bass evolved based upon what the drivers of any particular time period were capable of.