New Dedicated Home Theatre - First Ever DIY Subwoofer Project Guidance and Input Request (Modest/Basic Goals)

[stevecheck]

Hi All,

I have built a sealed 14.75' x 13' x 8.5' home theatre with multiple locations available for anything up to around 10 to 15 cubic feet, maybe even larger if necessary and it fits my budget. Very much prefer to keep things sealed and simple. I am looking for a clean 100dB at 20Hz that either extends down to 15Hz or has reasonable rolloff to 15Hz still above 90Hz, considering measurements at 1m distance. Whatever level the other frequencies above that are able to hit, I'm not really worried about. This is for 99.623% movies. I have no reference sound I have ever experienced besides going to the theatre and I'm not a super bass head. I just want to provide an above average listening experience to match the viewing experience I am creating in the theatre which is slightly above average, but not the best of the best. We like to get pretty good gear from a few years back when it is outdated and now inexpensive to pick up used as people upgrade to the latest and greatest. I built a 125" 2.4:1 AT spandex screen with frames of black spandex to cover the rest of the front wall. Walls and ceiling will be painted black, and will have black plush carpet. I have a Panasonic PT-AE8000U. Speakers are RTi A7's behind the black spandex frames on the sides of the screen, a Csi A6 mounted vertically behind the screen, RTi A3 surrounds, and 4 RTi A1's for ATMOS, all running through a Denon X4400H. Hope that gives you an idea of the experience we are going for. I will be doing acoustic treatments once I learn a bit more in that area.

Budget is difficult to pinpoint, but maybe around $500CAD. I'm looking at sources within Canada to avoid large shipping and duty expenses. I actually put a budget template together for a potential setup, but wanted to get some advice here first. I've researched the required tools and I am covered there. I'm not a rookie when it comes to woodworking but it's definitely not something I do regularly. This is something I would like to get into more, so I'm looking at this project as a potential starting point for that.

Item	Make	Model	Cost
Driver	Resilient Sounds	RS15	$167.90
Amp	Dayton Audio	DTA-100LF	$179.83
Wire	Solen	FT4/12-2	$2.94
MDF	HD	1/2" MDF 4' x 8'	$50.00
Glue	LePage	Pro Carpenter's Glue	$13.43
Screws	Paulin	1/4-20 x 30 mm	$5.20
Inserts	Paulin	1/4-20 x 20 mm	$6.40
Stuffing	Solen	Polyester Batting	$9.06
Feet	Not Required
		SUBTOTAL	$434.76
		TAX	$21.74
		SHIPPING	FREE
		TOTAL	$456.49

Definitely not locked into anything on here, and cant even remember if that driver modeled well in Winisd or not. I'm also looking at things like old Infinity 1260w's, JL 15w0's, a DS18 ZR15.4D, and anything else I can get my hands on for under $200CAD. For the enclosure, I do have a potential source of a large amount of 3/4" MDF on marketplace for $50 also just fyi. Also, the Behringer NX3000D is $650CAD and up, so its a no go. I'm pretty locked into something small with basic filter controls and likely no PEQ controls for an amplifier. I'm also considering taking apart a current old subwoofer I have and stealing that 175W amp. There's lots of professional gear I see with EQ capabilities but I don't know what kind of gear is actually usable for PEQ besides seeing the usual recommendations around the miniDSP 2x4 HD ($370CAD). My hope is starting with sealed and low-ish power keeps things safe, potentially a low cost amp with basic highpass filter capability to be extra sure, and then just pray to the invisible gods of room gain to guide the low end of my response curve . I've also seen some amps on marketplace with bass boost with an additional knob to set the Hz of the boost as well, so it seems to me there is stuff out there that is not an iNuke with built in DSP, but could work for my budget and basic needs, I just don't know what is useable or not, or what I might not be considering.

I'm not looking to spend a crazy amount, which I know is not the name of the game here, but I was wondering if my goals were reserved enough, that maybe some folks on here know of something I could put together that was modest in price but just gets me over that hump for what I'm looking for. I've been looking at drivers and amplifiers on marketplace and have seen a few low cost drivers that I can kind of hit my targets with, but I am very early in researching and learning this topic so I don't know if I'm missing something, or not considering something. I'm hoping to use this as a learning project as well. If this becomes something I want to invest more into down the line, this would be good experience to get started along that path.

 

Any help around drivers, amps, other suggested peripherals and any other basic guidance would be a huge help and I very much appreciate any help from you all.

 

Thanks so much,

Steve.

[maxmercy]

Lots of variables there.  If I were you, I would sim many options, including the room.  Use WinISD or a similar enclosure program and RoomEQ Wizard's Room Sim.

100dB capability at 20Hz (at the main listening position) means you will be playing movies at around -20dB on your receiver (if calibrated to cinema reference).  For many people, that is enough to satisfy them.  Clean 100dB at 20Hz is not easy on a budget.  With a low budget and limited power (100W), sealed enclosures will limit SPL and extend a bit further down low (using power), vented enclosures will limit extension by essentially 'boosting' SPL above tuning.  If you have woodworking experience, making a tapped horn/folded horn sub will get you a lot more SPL for a limited power/budget scenario.  There are plans out there for these enclosures.  Also multiple subwoofers can help tame room modes.  Nearly every small room low frequency setup benefits from EQ capability, but you have it with the Audyssey built into your receiver.  No need for lots of DSP if your receiver already has it.

I would also recommend buying a used/refurbished sealed/ported sub with an included plate amp which may let you know what will be 'enough' for you and you can then plan accordingly for upgrades.  One or two 10-15" subs should be enough to get you started, and if you are lucky, get a little room gain.  Look at ebay.

JSS