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Cabinet tuning frequency

Discussion in 'Amps and Cabs [BG]' started by chicoLow, Oct 11, 2018.

  1. chicoLow


    Aug 3, 2018
    I'm working on plans for a pair of 112 cabinets using Dayton PA310-8 12" drivers. They suggest a cabinet tuning frequency (F3) of 73 Hz. Reading other discussions on TB, I'm guessing that's too high for a bass rig. But I'm too ignorant about the nuances of this design parameter.

    I don't want to build cabinets that will kill drivers. I do want to get close to optimizing for a bass guitar.

    Advice will be appreciated. Thanks.
  2. Those might be the ones in the Kosmic unloaded guitar cab cum miracle bass cab conversion.
  3. chicoLow


    Aug 3, 2018
    After more study of the existing threads, I'm thinking I should tune the cab to the driver, i.e F3=Fs. Fs for this driver is 39 Hz. To reasonably tune the cab to 39 will require a slightly larger than minimum volume, but not by much. For a 4 string, this should also help prevent driver death.

    Am I headed in the right direction?
  4. This thread has a lot of good info:

    Basic Cabinet Tuning Tutorial?
  5. The PA310-8 works well in smallish cabs (1 1/4 to 2 1/4 cf). They produce a relatively tight, articulate tone with smooth mids (but not much in the way of upper mids presence). They don't excell at prroducing abundant lows or at rich, fat bass. A little bass boost can help, but can quickly eat up power. Tune in the 60-65 Hz range for the smaller cabs (1 1/4 to 1 1/2 cf) and 50-60 Hz for larger cabs (1 3/4 - 2 1/4 cf). Tuning lower will get some additional low bass, but at the expense of mid and upper bass thinness - the tone will be articulate but not rich or fat. It will also lower the excursion limited power handling. All of the recommended tunings will result in relatively low excursion limited power handling in the deep bass - a concern for 5 and 6 string players. Using the recommended tunings, watch the cone excursion at 'live' volume levels. If it exceeds about 3/8 inches peak to peak, consider getting a high pass filter (some heads have one built in).
    Last edited: Oct 12, 2018
    DukeLeJeune likes this.
  6. chicoLow


    Aug 3, 2018
    Hmmm. I keep coming up with weird (probably dumb) ideas.

    Based on the above from AstroSonic, and on the fact that I'm building two cabinets with identical drivers, I wonder about tuning them slightly differently. Say one at 55 Hz and one at 65 Hz. Or even more extreme - one at 39 Hz (Fs of the driver) and one at 73 Hz (the recommended F3).

    Would they work together at all? Or would it just be crap? Kill the drivers?

  7. BogeyBass


    Sep 14, 2010
    No need to tune at different frequencies.
    Phase response and impedances will be different.

    I'm gonna guess this driver prefers smaller volumes? Cause the usual barf high tunes suggestions clue in the response of this driver. Telling me it likes a small box. And to get anywhere near a Butterworth response it needs high tune.

    Simple bb3/bb4 Alignments will tune to the Fs of the driver. And it's a nice low 39hz. If people want more pretty pictures on the modeler then just reduce the volume to get more system Q. Not high tuning.

    I can't model the driver but sounds like it do fine in 1.4 to 1.6 cubic feet and just tune to 40hz.

    The manufacturers 80hz tuning sounds like a pa application. 70 , 65, 55hz these are all high tuned and pointless since the Fs of this driver is nice n low for a 12"

    Unassisted alignments look pretty on the screen. But high tuning for static response is unnecessary. The 3dB of extra bass you want comes from the bass knob on the amplifier.

    Speakers unload below Fb so higher you tune the quicker that happens. The system is for bass. In general we are talking 30 to 40hz fundamental. Tune low not high. The reflex reduces cone movement.
  8. chicoLow


    Aug 3, 2018
    OK. 1.5 cubic feet, 40 Hz, 2 slot ports of 1.5" x 6" yields a port length of 14.74". Sound reasonable?
  9. The good thing about using port tubes is that it is easy to change the tuning and choose what you like. IMO, 39 Hz would decrease the excursion limited power handling in the midbass - where you really need it. The 73 Hz tuning will result in a depressed mid and low bass, but would work well if the cab were on the small side (say 3/4 cf). If you simply must have a small cab this is a solution, but it leaves much of the bass capability of that driver undeveloped (it's a waste of a good driver). If you must go with a small cab, consider using a different driver - the Eminence Basslite S2010 works very well in 3/4 to 1 1/4 cf. The Dayton PA255-8 works impressively down to about 1 cf.
    Last edited: Oct 12, 2018
    DukeLeJeune likes this.
  10. chicoLow


    Aug 3, 2018
    I have no problem with 1.5 cf. In fact, doing the Butterworth calculation results in 1.57 cf. so that's what I'll build. Just trying to resolve the optimum cabinet frequency. And of course, there is no 'right' answer. My main goals are to have useful cabinets for a 4 string bass and cabinets that don't kill drivers. One for lower volume and another one to add when I need more.

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