Looking for a cheap ($300-$600) combo amp that can hit low A (27.5 Hz) at high volumes.

Most bass amps wont be able to produce go that low and be really loud at the same time. Best bet ia to find an amp that can be bi amped and has a built in cross over. Get a pa sub for the lows and maybe a 4 10 for the rest

 

Look at an SWR Silverado Special. Needing a Combo is limiting you as they rarely have numerous big speakers.

Can you try before you buy local? A Mesa Venture 212 would crush but they are out of your price range. Please keep us posted.

 

Yeah a PA sub (or four) is going to be the way to go for that.

 

Buy headphones.

 

The combo that you are wanting doesn't exist. Light, cheap, loud, and low....nah.

To go that low, follow the other advice. Biamp with inexpensive class D power amps into a sub. Used can be had pretty affordable. Good luck!

 

If you want deep bass its gonna be a big cabinet. Likewise the second harmonic is what is more audible with string instrument and a speaker system. So the 27.5 your aiming for is realistically achievable at high SPL at 55hz. Which is the lowest realistic F3 of decent 15" musical instrument speakers. A home sub might be great but your talking barely 80 to 85 dB. Literally be thousands of watts to get over a drummer. Musical instrument speakers have sensitivity around 96 to 99 dB. Anyways blah blah you need a 2x15 minimum to get that 55hz harmonic. And have enough power handling to cover a drummer

 

@BogeyBass hit your problem on the head. The problem is the speakers. I have seen some boutique combos that handle 20hz, but there does seem to over the counter speakers that like 30hz.

 

If you’re playing live, you’ll want to avoid 27.5 Hz, or anything lower than about 45 Hz. What you want is to give the very strong impression of hitting that low without actually hitting that low. If you’re actually generating frequencies that low, then you’re fighting against the FOH subs, and particularly the kick drum.

 

Also, read up on Hoffman’s Iron Law.

 

I want a brand new Ferrari for less than $10k. That's not going to happen either. Not even a Maserati. BTW, big loud lows come from the PA, not stage amps, and even PA subs don't do 27.5 Hz, not even $2k subs like this:
JBL VRX918SP | 18" High Power Powered Flying Subwoofer

 

As other people mentioned above you probably don't want to reach that low frequencies. They are barely audible. Take a look at the equal-loudness contour
Equal-loudness contour - Wikipedia

 

Did you google those bands' bassists and research which amps they are using? I read that one of them uses an ancient Peavey head he bought for $150. You don't have to spend a ton of money to get a loud, powerful rock sound (and you certainly don't need 27hz). Best way to get there on a tight budget is a used solid state head and a used 8x10 cab.

 

Yeah and I want a cheap car with 500 horses and Adrianna Lima in the passenger seat. Good luck

 

You'll also fight venue acoustics which will make your lowest freqs inaudible or sound like an indistinguishable rumble. Hey, that's what an HPF used to be called, a rumble filter. Wonder how it got that name?

 

The Case of the Missing Fundamental

From the page:
"The pitch your ear and brain "hear" is in each case not based on the harmonic with the lowest frequency; you "hear" rather the tone as having the pitch of the original fundamental frequency, even when it is not physically present in the signal!"

So in short, you don't need to reproduce the fundamental at 27.5, our ears and brains will supply it if it is missing.

 

Well, then I guess we're done talking about it, as to hit those frequencies (which you actually don't want to do) you're gonna need a lot more than 90 pounds worth of gear.

 

Get real - you don't need this - and to get even close to something that delivers an honest 40 Hz (let alone 27 Hz) that is usable on a real gig, its going to cost some money, need a big amplifier to power it and be a big pain to move.

Others on TB have spent some time and money chasing down sub-contra bass response only to find that it didn't make that much difference.

Pro audio subwoofers will probably get you the closest to low bass, but they'll be a little slower than you might like.

If this was a good idea, more people would do it.

 

I wonder why you want the rumble of a 27.5 Hz signal would give you. I use a High-Pass filter to get rid of that kind of frequency. Aren't you worried that your low end would sound loose and undefined?