Best way to amplify Sub Bass

[PocketPerson]

Wondering if anyone has a solution to amplifying a hefty amount of sub bass from a sub-synth pedal. In this case the Pigtronix Mothership 2, but for any sub range pedal.
The MS2 has a gnarly sub out jack that isolates the sub octave synth voice, I usually run that in a parallel channel on my pedalboard to my amp but I'm wondering if there is a better way?
I'm hoping someone can school me on what works best for such a signal? I have mulled around the idea buying a 2 x 15 cab to run my bass rig and keep the pedal in parallel with my clean or split it from my pedalboard to a separate powered sub, or bass amp(or keyboard amp?). In that case what size, and with 10", 12" or 15"+ speakers?

 

[rodl2005]

If that's your desire, a separate powered sub would be my go, I'd imagine

 

[crazyBassClown]

I'm hoping someone can school me on what works best for such a signal?

Depends on what you actually want. If you want to properly amplify the whole signal cleanly you need a full PA with Subs and tops, and if you want it loudly then you'll need a fairly decent sized PA and Sub, probably an 18 sub minimum if you want realistic gig volumes of room shaking bass
This same advice applies to bass and keys as well. Most bass amps don't amplify the lowest frequencies a bass guitar can produce at any significant volume either.

A bass cab is unlikely to produce either the highs or lows from a sub synth faithfully and neither will a keyboard amp. Running the signal through just a PA sub will only produce very low rumble and won't sound good at all.

 

[Wasnex]

What is the frequency range and how loud do you want it.

Keep in mind the Fletcher Munson curve. For equal perceive loudness, low frequencies must have higher SPL.

The phon is a level of perceived loudness. At about 1K perceived loudness in phons = the SPL level in dB.

So at 1K 100dB = 100 phon. But at 40hz you need 110dB for a perceived loudness of 100 phon.

Many subs don't play all that low. If I were to buy new subs, I would probably get JBL VRX918S. There are not entry level and current street price $1679 (each).

Specs say +/- 3dB 34-220hz. But take a look at the frequency response plot, and notice it rolls of sharply below 50hz. Seems a bit misleading.

If you want a sub that plays low and loud, you will need to spend a lot of money and it's going to be big. If you really want to be an overachiever, build some DTS10 | Danley Sound Labs These are -3dB at 15hz and capable of 127dB continuous. You will probably want at least 4 (min). They only weigh 285lbs .

The reality is you probably don't need the LF extension as our ears trick us into thinking it's there when it's not. That's not to say it wouldn't be cool though.

 

[Lostgallifreyan]

The timbre of the subsynth is critical if you want all its output directed to one cab. Unless that is determined, nothing else can be decided.

Is it a sub-audio boom, or a low, slow harmonically rich rasp that is wanted? That decision alone will dramatically change everything, so it really matters exactly what sort of sound you're wanting from that LF output.

I can think of only one even remotely generic answer that might work for both: a 70 Hz active crossover to get the line level signal's HF from the sub mixed to your main cab's output, and a big horn subwoofer for the deep end.