Hopefully I'm asking in the correct forum.

I simply want to know if the only way to get deep bass is with a big speaker or if there are other ways. A while back I was looking at an 18inch sub, I want deep, but not loud. My space isn't that big. If the only way to get really deep is with a big speaker, then that is just how it is.

This is the starting point for me to buy a system for my space. I know this becomes a terribly deep rabbit hole.

Equalizer.

More power.

Better speakers that respond in that frequency range.

Powered subwoofers are cheap.  Buy one.  I have on for sale on Craigs list.  Polk Audio front firing.

agree with the other poster.  a polk 10" powered sub in a small space would work wonders.  I have a fairly large family room and it sounds great.

You gotta move the air. Seriously. You need a device that can move lots of air at low frequencies, and tiny little girly speaker cones can’t do it.

Nearly impossible to provide any real answer without a shit ton more detail but yes effectively bigger speakers produce lower frequencies better.

Now - budget, ultimate goal, space, media, power etc. all play a major role in the balance of the system and appropriate response.


2 simple options:

1) If you actually want the sound a quality 10-12" should more than due
2) if you are looking for the feeling of deep base on an explosion etc look into bass shakers.

Well... getting really low-frequency bass involves a well-designed speaker.  Being bigger helps, but I've seen 18" subs that struggle to go really, really low, whereas smaller but better-designed subs WILL.  Quality and design, which unfortunately, don't come cheap.    Buuuuut... while making them bigger makes it easier to go low, it also makes it a lot easier to have poor audio quality, so the big, cheap ones aren't necessarily where you want to be.

Overall... once you're at 10" or 12", the only need to go bigger would be to push more power, since surface area is cheaper than excursion.  But even for more power, a lot of people will use multiple 10" or 12", maybe 15", instead of stepping up to 18s.

I use a pair of these at church nice subs

Move the sub around the room. Location can make a huge difference.

Bass is low frequency long wavelength.  Long wavelengths require large drivers.
To get loud bass you need to move a lot of air, the large surface area of large drivers helps and so does long excursion (the back and forth movement of the driver).
Tuning a cabinet really helps so the roll off point aligns with the frequency bandwidth of the driver and LFE signal.

Bass is also non-directional.  So you can place a large subwoofer behind something and get good response throughout the room.  Placing a sub in a corner gives multiple reflecting surfaces and can really enhance bass.

Several years ago I built a sono sub.  I used a 10" Titanic 2 driver and a dedicated 500W amp.  Used a 24" sonotube as the cabinet, the driver is down firing and it has a port tuned to 19Hz at F2.  The whole thing sits 36" high.
Put on the siege at Helm's Deep and it'll rattle the whole house.

That kind of sounds ideal. A good driver and a proper enclosure. I might even have a piece of 24-in sonotube.

You can only do that if you aren’t married. Otherwise it goes where you’re told.

Sometimes some forethought might help. First bring in a really huge sub, it doesn't even have to be real. Then when she goes nuclear say something like "Well, I don't know. Maybe if I took the little sub and moved it around the room it would stop sounding like crap, if you are really sure you don't like the sub that's as big as a refrigerator."

If you want deep but small subs. You'll need really powerful amps, woofers with a lot of excursion (xmax), and something to do precise DSP control. A pair of DIY subs, powered by a powerful pro sound amp with DSP is probably what I'd do.

Yeah, you can make low-freq sounds with ANY size driver, BUT... because power is associated with the square of the frequency, in order to make low-freq LOUD, you have to move a LOT of air.  You can do that with larger drivers or more excursion, both have realistic limits where it gets progressively harder to maintain sound quality.  10"-15" really seems to be the sweet spot where you can keep a good balance of intensity, quality, and price.

You have run into Hoffman's Iron Law of bass.  Pick 2 and the 3rd is chosen for you.

1. low-bass reproduction
2. small (enclosure) size
3. high (output) sensitivity

With enough power and a high excursion driver, you can use DSP (digital signal processing) to create a shelf filter to compensate for the low end in a small box.  That requires a lot of power and subs like that have their own issues like high inductance.  There are a few that have implemented inductance lowering features but you starting to get into $1,000 drivers.

I like bass and building subs.  I'm running dual 15's in my home theater now.  In storage, I have multiple 12", 15", 18" and even a 21" driver that I need to build boxes for.  I even have parts to build more 12" and 15" drivers (magnets, frames, cones, etc.).

I have a few specific newb questions for you. I fully understand that the answer to each question is probably going to result in me having to go learn what the answers actually mean, I will do that.
1) What is a good target Hz for bass that is actually useful while being very deep? If I'm not mistaken it is entirely possible to build a sub that is so deep it doesn't really go well with music, I think.
2) Once I have that target number, what are the parameters I need to look for in a driver? I'm happy to build a bigger enclosure instead of buying a more expensive driver to get to the same place. I believe I'll be looking at a 12in driver.
3) Do I need to purchase a receiver that has an ohm that matches the ohms of the driver? I'm confused on this one. 4ohm, 6ohm, 8ohm.
Thanks.

Humans can hear base tones down to about 20 Hz so if you want the whole range shoot for that or slightly lower.

The lower the ohms impedance (resistance) of the speaker the easier it draws from the receiver and the more it will draw. If your receiver can’t support low enough ohms speakers then you can run into trouble like heating and fuse blowing.

Think of your receiver as a dam and your speakers as a river. If you connect a big 4 ohm river to a dam that will only support a skinny 8 ohm river, you run out of water.

Go the other way and connect a little 8 ohm river to a dam that can support 4 ohms and you don’t draw very much water. Hopefully someone smarter than me will weigh in

1. If you are building a ported sub, then 20hz or so is pretty low.  I went sealed and have useful bass down to 17hz.  But it's a trade-off.  I use dual 15" drivers and each is getting about 900w.  It also took a better part of a day to measure the frequency response of the room and dial in the EQ.

Yes, you can go lower but that's just a tactile response where you feel the bass more than hear it.

2. Since you want a 12" then find the Hammer sub on YouTube.  There's also numerous sites with details.  It's easier than designing from scratch.

3. No.  The LFE (low frequency effects) channel on a receiver is a pre-amp signal that feeds a dedicated sub amp.  

Your receiver does need to match the impedance of your speakers though.  Most big box retail speakers are 8 ohms so any receiver will work.  I use 4 ohm speakers and my receiver is stable to 6 ohms.  It plays fine until there is a loud sound in the movie and it shuts down.  I got tired of that so I use the pre-amp outputs for left, center and right to feed pro amps.  They supply my speakers with 375 watts each.

You may think that's overkill and you would never listen that loud.  I don't.  That's what the volume control is for.  I have that power on tap but it only comes into play on dynamic scenes in movies.  It keeps the distortion extremely low since I'm not pushing the system hard.

Large driver, long excursion, high power.

It is not required to have big speakers for super low bass:
Rotary Subwoofer

Did not see a price constraint in your post or anything about not making house modifications

Solid advice. I had 4 x 18" sealed in a theater w 3600w between them. It would crush your soul and the amps wouldnt even be warm lol.

I'm tempted to stay with sealed subs but I have want to try ported.  I've recently built a lot of ported boxes for friend's cars and they all worked out great.

I have a 21" Exodus Audio Maelstrom that is screaming for a massive, ported box.  I think I can fit a box of about 15 cubic feet in the room and tune it to 14hz.

Holy crap. That's amazing.

The DIY version someone tried to build at AVS forum was great as well.  Fan blades mounted to a RC helicopter blade rotator things (not sure of the correct terms).

Fucking hell, that is cool!

You can get deep bass best through powered subwoofers in one of two common options:

1. A large driver, 12 inches or more, with plenty of power
2. A small-medium driver, 8-12 inches, with even more power and more excursion.

JL makes a nice powered sub that is very small with huge output, but it’s expensive.

You’re best looking at the Monoprice line, as they have a very affordable 15 inch sub.

Tower speakers that are capable of a sub output tend to be very expensive and need a lot of power.  A lot.

Inexpensive, or small. One or the other, but not both.

ive had good luck with these
lately

https://www.svsound.com/collections/subwoofers

but

I built my personal sub years ago when money was tight

I used a good quality 12" sub, a box I built and powered it with a Behringer mono amp