Small Sub

[titanif]

Hello,
I have built a small set of full range speakers and I now need a subwoofer for them. It's based on the HiVi B3S and they need a little help from 150hz and lower. Intended use is for light music and TV. Not a full blown, rumbling home theater, just something to replace my crappy TV speakers and listen to some background music. It will be used in a large living room, and NOT nearfield.

What are good small subs designs I could build myself? I've se a few youtube designers like Toid and Hexibase... Are they any good? I am open to any suggestions. If they are small enough, I could build 2 of them. I'm even open to a transmission line design. Anything that has a good reputation?

[JonMarsh]

Need more info to help-

• What's your budget?
• Are you considering one or two? Two helps out with dealing with room acoustics and variations. If you want to go 150Hz and lower, I'd recommend two subs, one placed close to each of your mains- 150Hz is a higher crossover point compared with the usual 80Hz or 100Hz.
• Do you already have a way to power them, or plan on plate amps? Budget?
• 150Hz or higher would make sense with the B3S, it's normal roll off is at 100Hz, and you should crossover above that, IMO.
• I'm not familiar with the YouTube designers you mention- how about some links if you'd like us to check them out?

If I had to make a screaming fast suggestion for what you describe, and considering the possibility you may not have much woodworking gear, I'd consider this cabinet kit from Parts Express, and the matching 8" HO driver (designed for small enclosures), and a plate amp for each speaker.

https://www.parts-express.com/Knock-Down-MDF-0.75-ft-Subwoofer-Cabinet-for-D-300-7075?quantity=1

https://www.parts-express.com/Dayton-Audio-RSS210HO-4-8-Reference-Series-HO-Subwoofer-4-Ohm-295-458?quantity=1

The RSS210 series has a stiff linear cone, works well higher up (even into the midrange) and relatively low inductance, and stable impedance free of rising distortion with rising frequency above 100Hz, unlike a lot of other subwoofer drivers. The HO variant is designed to work in smaller enclosures. The HF variant is more sensitive, but needs bigger enclosures- it's one of my favorites for LF applications, due to its fairly Wideband linearity.

[wolf_teeth]

How big is 'small'? Agreed we need a budget estimate.

Hexibase usually prints for car audio based projects, so they may not apply to your situation.
Toid would possibly have a solution, but how good is it?

I agree with Jon's recommendation being quite valid. I'll even go one further and say the Dayton MX10-22 in the same sealed and stuffed box kit size with the Dayton SD300-6 and boost engaged is quite the potent overachiever.

My Biumph design by comparison is a 9.5" cube with a driver and PR and 50W max power handling. Place it in a corner, and be amazed.

I also used the Dayton UM8-22 in a 0.5ft^3 sealed without boost and 200W on tap. Placed adjacent to walls, this can also perform quite well. Just watch the gain as it can protest heavily when it gets into the clipping or suspension limits.

In subwoofers, there are many options.

[tktran]

My method is to start with the cabinet first. Decide on how big you (or your partner) can tolerate. Use mock-up cardboard boxes if you want to see how it will look.

Then work backwards and calculate now much internal box volume you can use to design your cabinet (assume 5/8 or 3/4" thick MDF stock)

Do you have some way of measuring how loud you generally listen? This will help determine subwoofer requirements.

If you can't, I find a good rule of thumb is at least TWO sizes up from your mains.

eg B3S - 3" driver. 2 x 3" >4".
So a 5" ported subwoofer would be a absolute minimum to be worth building.

For bass, it's not about budget, it's about Vd (Sd times x-max)

2. Then getting the subwoofer to play nice with the satellite is an important step.

[1Michael]

And...what are the dimensions of the space it will go in?