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I wanted to build a portable boom box for work. I work in an engine test lab so the engines and emissions / supporting equipment is quite loud 80-89db in my console room. So i wanted something that would top out spl in the mid to upper 90's before breakup.
Build / design goals
Have a funny name haha! Really the goals were simple keep it under $150 total. Consume less benchtop / toolbox / desktop space (less that my milwaukee jobsite radio), improve SQ and low end. Lastly, hopefully impress people at work and get them into speakers.
DRIVERS
Tang Band W3-2141 3" paper cone full range $33 each
http://www.parts-express.com/tang-band-w3-2141-3-paper-cone-full-range-driver-8-ohm--264-956
Tang Band W5-1138SMF 5-1/4" Paper Sub $32
http://www.parts-express.com/tang-band-w5-1138smf-5-1-4-paper-cone-subwoofer-speaker--264-917
THE AMP
I upgraded the PSU to a 12v 5amp supply i had instead of the 12v 3amp it comes with. This amp was cheap price wise and appeared to have a ton of adjustability. It has tone controls for bass and treble on the L/R (-10 to +10 (probably not true)), a volume pot for L/R, a frequency cutoff for the sub and a seperate volume control for the sub. I have used the amp or gotten to measure any drivers at this point but im getting close. Perhaps i can get by without a crossover or just cutting the LF signal to it. Ill know soon if i can do that or not.
Lepai LP-168ha-21 (2x40w and 1x68 sub). ($28)
http://www.parts-express.com/lepai-lp-168ha-21-2x40w-mini-amplifier-1x68w-sub-output--310-308
1.5" X 9" port (PVC) for sub port X1 qty
Everything from like 7" to 10" should work in this enclosure.
4" X 6" PVC enclosures for FR drivers X 2 qty
I recessed a 1/2 thick plywood insert in tbe back of the pipe and recessed it into the baffle by about a 1/4 inch. Its approximately 1 liter internal volume.
The enclosure
Approx 12 liter enclosure. (1liter for each driver, so approx 2 liters total + the 1/4" thick pvc sealed) and that leaves 9-10 liters for the sub (minus the external dimensions of the 1 liter cabinets with are 1/4" thick pvc. Its roughly 17wx8.5hx8.5d
Current minor holdup:
I'm currently looking for a more elegant way to install binding posts or something because I need to run 3 pairs of wires through the back of the cabinet. My thoughts are using a piece of plexi glass and just route out enough meat of the cabinet to have that I can attach binding posts (I have a ton of binding posts but they are like a bit less that 1/2 thick or something so they can't get through 3/4" thick mdf. I could disassemble them and use a forstner to rebate them into the cabinet by like 1/2 or something. here are the binding posts I have http://www.parts-express.com/parts-express-dual-binding-post-1-red-1-black--090-475
Lastly I bought this to wire them but I doubt I will use it. It says it's 14 AWG but there is no way it is that 14, I got both 14ga and 16ga but the 16 seems like 20ga or 22ga and the 14ga seems like 18ga at best. For this power level maybe it's not necessary to use legit 16 or 14gauge but I have extra so maybe ill use it instead.
http://www.parts-express.com/jsc-wire-14-awg-red-black-zip-power-speaker-wire-1-ft-usa--100-060
Ill get pics uploaded tonight after work.
Comments
Most of the small digital amps that I have measured put out about half the power the manufacturer rates them at before the start to clip. That should still be plenty with the drivers you picked.
Ron
Im kind of confused now. Ill regroup with some shut eye but if anyone has suggestions let me know
I wont be posting until late tonight/tomorrow i hit my stride at 1-3am now on second shift.
This is the Bass Tone control Knob adjustments for the W3 full range driver ranges
(-10, 0, +10). This function actually does work. I'm not 100% certain why the top end dip's off like that but I will try with a real amp tomorrow night or something.
This is the "TREBLE" Tone control Knob adjustments for the W3 full range driver ranges
(-10, 0, +10). This function actually does work as well
This is the Near Field and Farfield of the W3 Full range driver no EQ for bass / treble
This are the Dats data for the TB_ W5 5-1/4 sub
This is the Sub cut off frequency pot test. I changed it in increments from 200-hz to 50hz. It really didn't change much at all. Also, I can barely add any power to the sub without it making a weird noise.
I used a tiny dayton amp and my apa150 and it works perfect but the amp is almost as big as my boombox lol.
https://www.amazon.com/Nobsound-Channel-Integrated-Amplifier-Bluetooth/dp/B0196HF0MU/ref=sr_1_10?ie=UTF8&qid=1485369509&sr=8-10&keywords=nobsound+2.1
Sample size of 1, so YMMV. Pretty versatile.
I honestly don't remember when I got into this hobby. I got in back when the tritrix first came out but I just had crappy tools like a chop saw, jigsaw, circular saw. I think i got my good table saw about 3 years ago. Travis helped me with the tarkus build. It's been a fun experience and I got to meet all you guys in the process. I tend to be pretty shy but I think the amount of people at these events helped me get used to talking to alot of new people and speaking to alot of people at once.
Hope there is a chicago get together of some kind this year. I don't think ill make it to fortwayne this year.
I could see Marvin, Scott Sehlin, and maybe even Ron E making it. Not too far for Pete S and John H either.
Ron