Amplifiers for 8-30hz 3000W+, how do I know they can deliver?

[BigStreetCinema]

First post!

Love this forum and all of I want to know is already written so don't have to do any new post.
But now I have a question.

Having 7 BMS 18N862 in sealed boxes with 2x Lab Gruppen FP10000Q, original made in Sweden.

But looking for infra project 8-30hz.
In EU we don't have many option on drivers.

But my question is about the amps and how they can handle 8hz and how to find out how much power they could deliver.

If you look at Lab Gruppen IPX 4800 have response:
(I have 10 Lab Gruppen amps today)
10 Hz to 20 kHz, +0.5/-1 dB
5 Hz to 40 kHz, -3 dB
2x2400W 4ohm is little to little but an example.

How do I know the amplifier deliver 2400W in 10Hz for example.

Looking more at amps like
Lab Gruppen PLM20K44
Dream would be Powersoft X4L

Some DSP have a HP filter so need to know if it possible to disable.

Any thoughts or amps I should be looking at.

At least 3000W 4ohmand 4 channels

 

[staticV3]

Any ideas, @peniku8?

IIRC you've measured a number of PA Amps yourself, and probably researched many more.

(Welcome to ASR, @BigStreetCinema!)

 

[BigStreetCinema]

Any ideas, @peniku8?

IIRC you've measured a number of PA Amps yourself, and probably researched many more.

(Welcome to ASR, @BigStreetCinema!)

Thanks

Great to be here

 

[peniku8]

I'm a big fan of Powersoft amps, having 4 myself, but they come with some drawbacks regarding infrasonic applications. They're made and optimized for live sound, which means 30Hz+ and higher crest factors than what you'll (likely) be working with. They burst insane numbers, but their internal long term current limiters will typically limit them to about a tenth of the rated power specs when it comes to lowZ long term averages, so you'd have to oversize them, unless you're already at the limit of what the drivers will be able to handle (I'd say 1 X4L for something like 8 21IPALs would generally be a good ratio). I'm assuming you're talking (home) theatre here and not live sound reinforcement. Because if it's the latter, then good luck. I haven't measured the X series, but all their other amps behave similarly, except the M-Drive.
I repaired and upgraded my "Sanway" FP-13000 last week and took some measurements, which I can post here in a bit. Those clone amps output good power and are reliable enough for a home theater installation, but I personally wouldn't feel great about deploying them for a live show.
About headroom regarding very low frequencies, my theory and my experience with measured data shows a somewhat predictable relationship between the frequency response measurement and output power. If the frequency response is flat down to frequency X, you can expect the amp to deliver the same amount of power into frequency X than at 1KHz. If the frequency response is -3dB at say 5Hz, it's possible that the amp can only output about half its rated power into 5Hz, but not a given. If its simply an AC coupled input, I'd expect to be able to make up for the droop simply by increasing the input gain, but if the gain reduction happens somewhere in the output stage and the amp isn't able to output the same voltage levels even unloaded, it seems like most of the time it won't be able to deliver its full power, even when not voltage limited.
Some amps do have ULF protection circuits which you can't turn off, so you'll have to look into the manual to see if that's the case.
In any way, for amps like that I'd recommend sticking with Class D and PFC. If you want internal DSP I think nothing beats Powersoft. If an external dsp is okay and you don't need the most elaborate driver protection circuits because you're not expecting to run the drivers at their limits, then a cheap alternative can be the new GaN based CN amps. Altho their data-sheets conflict themselves and I wouldn't expect them to reach their claimed power specs (from what I've seen, the given maximum voltage output is Vpk which means all power figures listed are double the actual figures).
When it comes to drivers for very low frequencies it depends on what kind of box sizes you can accomodate. If you need to be space efficient, I think there is no way around M-Force. If the boxes can be huge, there are a bunch of car audio drivers that could be interesting (with Stereo Integrity not being generally available in the EU). If you need well behaved drivers for a medium sized box, the 21IPALs look great, along with a few other options from Eminence, Faital and B&C themselves (new RS series).