Small sub for bedroom

[ALTRE552]

I'm looking to build a sub using this plate amp.

Dayton Audio MCA2550E 2.1 Channel Class D Amplifier

It'll be used to complement Zaph's HiVi B3S speakers. The set-up is for my PC, nearfield music listening 90% of the time, movies/TV the other 10%. So I don't need window rattling bass, clarity is more important to me.

I'm not too sure where to start with sub building. I have the skills & tools necessary to build one, just need a place to start in terms of the design. If someone could point me in the right direction that would be much appreciated!

 

[TheBaronGroog]

How small does it have to be?

What have you built before?

What do you want to build now? Simple and quick? Or more complicated and time/brain consuming?

What's your budget for the driver?

A single 6.5"/8"/10" in sealed/vented/TL/Horn could all work for you in an enlcosure beside/under your PC desk-otherwsie have you space under your bed? I'm looking at using a pair of 8" in a horn under my bed-no real space lost and can build a good sensitive enclosure and get some low end for movies

 

[ALTRE552]

Thanks for the reply matey! I've done a bit more research on things.

How small does it have to be?
Less than 30L would be ideal, but I could probably squeeze up to 45L under my desk.

What have you built before?
I haven't built speakers before. I've done a lot of woodwork (benches, blanket chests, bookcases etc) and also have a physics degree, so I've got knowledge of circuits.. .but it's more theoretical than practical. I can solder though.

What do you want to build now? Simple and quick? Or more complicated and time/brain consuming?
I'm going to say... elegant . Something relatively simple.
For the first build I just want something solid that works well and doesn't give me any future problems/forever tweaking.. I've been down that road a few too many times.

What's your budget for the driver?
Around $50 would be nice. I currently have my eye on a Dayton 8" sub for $50.
Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm
Fs: 30hz
Vas: 33.7L
Qts: 0.55

I'm looking at using a pair of 8" in a horn under my bed-no real space lost and can build a good sensitive enclosure and get some low end for movies
Sounds kinky mate, I'm on to ya...



If I'm on the right track, the Dayton sub should be optimum at 9.4L sealed (flat to 100Hz, -6dB @ 50Hz). I've been messing with WinISD and with a ported 25L, I should be pretty much flat to 40Hz and -6dB at about 32Hz.

Am I doing it right?

 

[revboden]

doing it right... huh... yes

watch excursion for ported designs and vent velocity (keep it below 12 m/s) For the design above you'll need a 10cm diameter port 79cm long (it becomes a complex system when you know about all the parts eh )

Also, put high-pass filters to good use (with the ported design above you'll need one at ~30Hz, second order should do)

for sealed boxes, well... they are hard to mess up, it's a box. panel bracing and some damping are the only things to worry about.

 

[planet10]

The last part of this post is applicable to your situation... you might also want to read some of the earlier posts.

http://www.diyaudio.com/forums/full-range/196204-recommendations-please-3.html#post2708573

dave

 

[djginwis]

I have used that 2.1 plate amp for two small 2.1 systems. The sub was about a foot square ported with a TangBand W8-740C. I just happened to have some of those. There is a design on the PE showcase called the Triska that uses the Dayton DVC and two passive radiators. There is a sub on rjb audio's site called the Cerberus that uses a 6.5 TangBand neo woofer. That speaker has gone up to around 100 dollars. both use the Dayton 70 watt plate amp. I have built both of those designs, and they are fine for a small system. I think both would work with the 2.1 amp. Good luck.

 

[bjorno]

..How small does it have to be?
Less than 30L would be ideal, but I could probably squeeze up to 45L under
..What do you want to build now? Simple and quick? Or more complicated and time/brain consuming?
I'm going to say... elegant . Something relatively simple.
..What's your budget for the driver?
Around $50 would be nice. I currently have my eye on a Dayton 8" sub for $50..Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm..I'm looking at using a pair of 8" in a horn under my bed-no real space lost and can build a good sensitive enclosure and get some low end for movies

Hi ALTRE552,

FYI, If you like folding challenges : Here follows a couple of sub simulations using inexpensive drivers that think should work well with your suggested amp:

b

 

[TheBaronGroog]

No problem.

With Winsd and that space a decent ported anclosure should be no trouble for you, as others have said watch excursion below box tuning. Sealed are much easier to build and more forgiving of mistakes-but not the same degree of "fun" in designing or building them. Build the 25l vented and if you don't like the sound of it you can always block the port and add balast to make the compact sealed

So you've heard of C.R.F then

 

[johnr66]

If you don't need window rattling bass and listen to music 90% of the time. I'd go sealed. Excursion below tuning, port noise and transient response are less of an issue (non issue for the port since there is none). I'm of fan of efficient speaker design, but after putting a decent 12" driver in a 48L box, I will never frown on sealed designs again. It works beautifully with music and only getting 20 watts of power, fills my living room with plenty of bass.

Sometimes simple is best.