Mini ~$150 Ultimate Boom Box Lepai 2020 ++ ??

[ph123]

Hi Everybody,

Thanks for the awesome forum and all the knowledge I have found here. So now I am making my own boom Box that I want to take outside to the fields where we play Ultimate Frisbee / Goaltimate. (Ok, that last part is irrelevant.) The relevant part is my friend Adam brought out this awesome DIY BBOX with a Lepai 2020 (http://www.amazon.com/Lepai-Tripath-TA2020-Class-T-Amplifier/dp/B0049P6OTI/ ) that sounded great, and I wanted something just a little better.

Anyway, he convinced me to get the amp, and I am searching for very efficient (marine?) speakers. He got these: http://www.amazon.com/Audio-MR50B-5-25-Inch-Marine-Speaker/dp/B000FKP7MQ/ref=sr_1_9?ie=UTF8&qid=1320870992&sr=8-9

I am considering these: http://www.amazon.com/Infinity-Refer...rhf_dp_p_img_1

or these:

http://www.amazon.com/Polk-Audio-6-5.../ref=de_a_smtd

Can anyone recommend better speakers?

And is there any chance there is a cheap Equalizer that can be added without destroying my SLA 12 v 7 mah batteries life? (6 hours preferred...)

I am also considering using a pair of existing Boston Acoustics A-40 as the speakers with a little box & (sideways) H clamp to hold the components and speakers together.

Sorry for the incredibly NOOB post, but I'm hoping to get up to speed soon.

Thanks for all replies. Much appreciated.

[rustyyy]

Did you get a resolution on this? I'm building the same thing with the same amp and am in the same place as you - when you posted this.

[Teti]

Coincidence? Are you related or something?

[pegodk]

I built a similar thing last summer. Used a cheap amp 2*15W (from sureelectronics) a lead battery, about 5-6 ah. I made it a stereo build, but added a contact to shut off the back side if extra battery time is needed.

I used the woofer SP-60/4 from monacor. This is an amazing driver! It has an impressive low response from even small volumes. Also it goes quite high in frequency, so u can just get a cheap tweeter and do a simple 1st or 2nd order crossover around 4-6k Hz. The sensitivity is also quite good btw (90 dB from a 4"!). For tweeters I used D28 from dynaudio, but that was just because i had those laying around. If u don't want to mess around with crossovers u can try piezo horn tweeters.

cheers

[Cal Weldon]

I like the red tool box idea.

[xrk971]

Cal,
Are those mondo woofers or passive rads? It would be cool to take a rea steel craftsman toolbox and do this.

[xrk971]

Originally Posted by ph123

Hi Everybody,

Thanks for the awesome forum and all the knowledge I have found here. So now I am making my own boom Box that I want to take outside to the fields where we play Ultimate Frisbee / Goaltimate. (Ok, that last part is irrelevant.) The relevant part is my friend Adam brought out this awesome DIY BBOX with a Lepai 2020 (http://www.amazon.com/Lepai-Tripath-TA2020-Class-T-Amplifier/dp/B0049P6OTI/ ) that sounded great, and I wanted something just a little better.

Anyway, he convinced me to get the amp, and I am searching for very efficient (marine?) speakers. He got these: http://www.amazon.com/Audio-MR50B-5-25-Inch-Marine-Speaker/dp/B000FKP7MQ/ref=sr_1_9?ie=UTF8&qid=1320870992&sr=8-9

I am considering these: Amazon.com: Infinity Reference 6032cf 6.5-Inch 180-Watt High-Performance Two-Way Speakers (Pair): Car Electronics

or these:

Amazon.com: Polk Audio DB651 6.5-Inch Coaxial Speakers: Car Electronics

Can anyone recommend better speakers?

And is there any chance there is a cheap Equalizer that can be added without destroying my SLA 12 v 7 mah batteries life? (6 hours preferred...)

I am also considering using a pair of existing Boston Acoustics A-40 as the speakers with a little box & (sideways) H clamp to hold the components and speakers together.

Sorry for the incredibly NOOB post, but I'm hoping to get up to speed soon.

Thanks for all replies. Much appreciated.

I have thought about this too. Have not built but think about it. If using in a ball field, you will need more oomph than Lepai (great amps, but too small for this app).
Use a Sure amp board with Tripath chip, one with 4 x 100 watts (you won't drive anywhere neat this). Use car audio coaxial speakers like Pioneer 6.5 inchers, 4 of them. Make 4 sided box and drive them in bipole that is opposite mounted speakers same channel and in phase, one driver per face. Use 4 x 12 v sla batts in series to get 48 volts to drive Sure amp to get sufficient watts. This should let you drive a solid 80 watts of power per driver.


Pioneer coax 6.5 $30/pair ot $60 for 2:
http://www.amazon.com/Pioneer-TS-G16...er+coaxial+6.5

Sure Tk2050 amp $52:
4x100W @ 4 Ohm TK2050 Class-T Digital Audio Amplifier Board 320-302

7.2 AHr SLA batt x 4 @ $16 ea = $64
http://www.amazon.com/B-B-Battery-Se.../dp/B0001XE11K

So I broke the bank at $176, but system will kill your friend's Lepai box.

I am assuming you can scrounge up a plywood box , or use an old cooler with wheels. Wiring, etc. You need to put dividers internally to isolate drivers for best effect, but common chamber can work, use winisd to size port for 4 driver bass reflex.

Have fun!

[xrk971]

Sorry, I just checked specs on amp and 32 volts max so you only need 2 batteries at 24 volts, thar will save $32 so you are below $150 now

[JMFahey]

Nice. *Very* cool construction
I always make 12V 7AH Gel Battery amps , usually with TDA2005 or bridged TDA2003.
The trick lies in using efficient speakers; I use 10" 4 ohms guitar ones (think Jensen C10R or MOD1035) plus piezos, for maximum bang for the buck.
That said, now I'm making a smaller one with just a little 1.3AH battery and one of those generic 6" foam edge light curvilinear cone "Background music" types, simply to save weight and space.
I'll use it to amplify my MP3 player, I'm sick of listening with headphones and want to make it truly portable.
Will post some pictures when finished.
And again congratulations on your good work

[xrk971]

JMFahey,
Are you talking about Cal's red toolbox? He has a cool mp3 player with down firing sub called the Pentagon.