building diy boombox

uranhjort · 5th December 2011, 11:38 AM

i've been wanting to make my own boombox for some time now, so i've been searching around on the net looking for stuff.

i have been looking at this class D amp:
Kicker DX125.2 (11DX125.2) 2-Channel Car Amplifier

and this battery:
Yuasa NP12-12 - 12V - 12Ah (F250 6.3mm)

i don't know what speakers to choose though so i hope some of you could help me with that?
the quality of the sound is not the priority with this. i would like for it to be as loud as possible

sreten · 5th December 2011, 12:43 PM

Parts Express DIY Project

Hi,

If you want decent battery life a smaller amplifier is the way to go.

Lepai Tripath TA2020 Class-T Hi-Fi Audio Amp w/Power Supply 310-300
Has tone controls and comes with a supply I assume you could mod to trickle charge the battery.

rgds, sreten.

PressureFM · 5th December 2011, 10:05 PM

You should definitely take a glance at the Boominator thread.

HifiBoyDenmark · 6th December 2011, 09:09 PM

the amp6 basic at 41hz.com from sweden i think.. the way to go

uranhjort · 7th December 2011, 10:07 AM

the amp6 basic kit is something i have to make myself right?
anyways. if i use that and the yuasa np7-12 7Ah battery, how long would the battery life be at full volume? and what speakers would you recommend?
Thanks

sreten · 7th December 2011, 02:51 PM

Hi,

Its hard to say because at "full power" really means music programme that
is clipping, how often and where in the music programme depends on that
programme, and the average level of that programme depends on the
dynamic range or crest factor of that signal. Music signals spend > 80%
of the time at levels < 20% of clipping level, for decent quality music.

The AMP6 is up to 2x25W I understand.

Assuming 20% average at clipping gives about 10W. 80% efficiency
implies around 12.5W draw which we might as well call 1A at 12V.
At 1A a 7AH battery should last 7 hours. A smaller amp will double
that as will turning down the volume a little, for volume what you
want is high efficiency speakers, not a high powered amplifier.

rgds, sreten.

Saturnus · 7th December 2011, 03:15 PM

An SLA battery average 12V. 13.5V when fully recharged and should be cut off at 10.5V.

The amp6 therefore outputs 2x8W into 8 ohms speaker because the efficiency is roughly 89%.

And 2x15W into 4 ohms speakers because the efficiency has dropped to roughly 84%

Measured power consumption at "full music power with no or slight clipping" is roughly 350mA into 4 ohms speakers and 210mA into 8 ohms speakers.

So a 7Ah SLA will last between 20 and 33 from fully charged to fully depleted.

uranhjort · 7th December 2011, 03:40 PM

ohh okay. so something like this would be able to play loud?
Infinity - Car Audio

picowallspeaker · 7th December 2011, 04:42 PM

With a little help from my friends
Bari, il concerto è alimentato interamente dalle biciclette | Roberto Rotunno | Il Fatto Quotidiano

uranhjort · 7th December 2011, 04:44 PM

sorry for double-post, but can't se any way to edit an earlier post.

just saw that those infinity kappa speakers are 2ohm. could that be a problem if i used the amp6-basic kit?

5th December 2011, 11:38 AM	#1
uranhjort diyAudio Member Join Date: Dec 2011 Location: copenhagen	building diy boombox i've been wanting to make my own boombox for some time now, so i've been searching around on the net looking for stuff. i have been looking at this class D amp: Kicker DX125.2 (11DX125.2) 2-Channel Car Amplifier and this battery: Yuasa NP12-12 - 12V - 12Ah (F250 6.3mm) i don't know what speakers to choose though so i hope some of you could help me with that? the quality of the sound is not the priority with this. i would like for it to be as loud as possible

5th December 2011, 12:43 PM	#2
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Parts Express DIY Project Hi, If you want decent battery life a smaller amplifier is the way to go. Lepai Tripath TA2020 Class-T Hi-Fi Audio Amp w/Power Supply 310-300 Has tone controls and comes with a supply I assume you could mod to trickle charge the battery. rgds, sreten. __________________ There is nothing so practical as a really good theory - Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

7th December 2011, 02:51 PM	#6
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Its hard to say because at "full power" really means music programme that is clipping, how often and where in the music programme depends on that programme, and the average level of that programme depends on the dynamic range or crest factor of that signal. Music signals spend > 80% of the time at levels < 20% of clipping level, for decent quality music. The AMP6 is up to 2x25W I understand. Assuming 20% average at clipping gives about 10W. 80% efficiency implies around 12.5W draw which we might as well call 1A at 12V. At 1A a 7AH battery should last 7 hours. A smaller amp will double that as will turning down the volume a little, for volume what you want is high efficiency speakers, not a high powered amplifier. rgds, sreten. __________________ There is nothing so practical as a really good theory - Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

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5th December 2011, 10:05 PM	#3
PressureFM diyAudio Member Join Date: Apr 2011 Location: Denmark	You should definitely take a glance at the Boominator thread.

6th December 2011, 09:09 PM	#4
HifiBoyDenmark diyAudio Member Join Date: Nov 2011	the amp6 basic at 41hz.com from sweden i think.. the way to go

7th December 2011, 10:07 AM	#5
uranhjort diyAudio Member Join Date: Dec 2011 Location: copenhagen	the amp6 basic kit is something i have to make myself right? anyways. if i use that and the yuasa np7-12 7Ah battery, how long would the battery life be at full volume? and what speakers would you recommend? Thanks

7th December 2011, 03:15 PM	#7
Saturnus diyAudio Member Join Date: Jun 2005 Location: Copenhagen, Denmark	An SLA battery average 12V. 13.5V when fully recharged and should be cut off at 10.5V. The amp6 therefore outputs 2x8W into 8 ohms speaker because the efficiency is roughly 89%. And 2x15W into 4 ohms speakers because the efficiency has dropped to roughly 84% Measured power consumption at "full music power with no or slight clipping" is roughly 350mA into 4 ohms speakers and 210mA into 8 ohms speakers. So a 7Ah SLA will last between 20 and 33 from fully charged to fully depleted.

7th December 2011, 03:40 PM	#8
uranhjort diyAudio Member Join Date: Dec 2011 Location: copenhagen	ohh okay. so something like this would be able to play loud? Infinity - Car Audio

7th December 2011, 04:42 PM	#9
picowallspeaker diyAudio Member Join Date: Apr 2007	With a little help from my friends Bari, il concerto è alimentato interamente dalle biciclette \| Roberto Rotunno \| Il Fatto Quotidiano

7th December 2011, 04:44 PM	#10
uranhjort diyAudio Member Join Date: Dec 2011 Location: copenhagen	sorry for double-post, but can't se any way to edit an earlier post. just saw that those infinity kappa speakers are 2ohm. could that be a problem if i used the amp6-basic kit?

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