Ok so this should be an ongoing project that may take all summer but I don't really know.
I want to build a boombox to kill all the 1200Watt Super BASS ULTIMATE! boomboxes out there. I am thinking of using the elf's as speakers or some 2-way joby, and I think the gainclone amp would do well. The main diffucultly will be the tuner and the cd player. Currently I think that it would be hard to run this whole system off batteries and still be able to cary it around, Unless I use cordless drill batteries maybe. So for now it can be AC powered. Mostly it will be integration and chassis design so I would love to hear suggestions from people to start me off, specifically in the CD tuner category. Thanks for the help.
Milo
PS I dont plan to make the cdplayer or the tuner but rather mod them from other things, like a computer cdplayer or something.
I want to build a boombox to kill all the 1200Watt Super BASS ULTIMATE! boomboxes out there. I am thinking of using the elf's as speakers or some 2-way joby, and I think the gainclone amp would do well. The main diffucultly will be the tuner and the cd player. Currently I think that it would be hard to run this whole system off batteries and still be able to cary it around, Unless I use cordless drill batteries maybe. So for now it can be AC powered. Mostly it will be integration and chassis design so I would love to hear suggestions from people to start me off, specifically in the CD tuner category. Thanks for the help.
Milo
PS I dont plan to make the cdplayer or the tuner but rather mod them from other things, like a computer cdplayer or something.
You could look at the old NEC SCSI CD-ROM drives. Most of the external SCSI ones have a display and control buttons, but require a caddy to load the disc. I saw a site where someone had modded a caddy based drive to be a "top loader". Most people who use these in audio are using them as a transport with an outboard DAC. There are audio and TTL digital outs on the back of the drive.
I think the model numbers are the CDR-601/602 for the external 4x/6x speed drives. There's also a top loader, the Multispin 3XP (CDR-400) that may be of use.
Figure on providing the drive with +12V @ 1amp and +5 @ 1amp .. Though I haven't measured what mine draw, that's what the switching power supply on the enclosed external version provides.
They're pretty cheap on Ebay ($10ish + shipping), or if you have a computer recycling/used computer store in your area, you might be able to find one there.
I think the model numbers are the CDR-601/602 for the external 4x/6x speed drives. There's also a top loader, the Multispin 3XP (CDR-400) that may be of use.
Figure on providing the drive with +12V @ 1amp and +5 @ 1amp .. Though I haven't measured what mine draw, that's what the switching power supply on the enclosed external version provides.
They're pretty cheap on Ebay ($10ish + shipping), or if you have a computer recycling/used computer store in your area, you might be able to find one there.
I'd of thought the obvious choice would be a car head unit.
Should run off a 14V source (13.8) perhaps a touch more.
If its a 4 channel unit with bridged outputs should manage
~ 25W per channel into 4 ohms and theorectically 50W per
channel into 2 ohms if the the unit can handle the current.
Speaker design is presumably is about compact efficiency.
I'd suggest a combination of a small sixth or 4th order
bandpass and a sealed high efficiency unit for mid treble,
with possibly a extra tweeter driver for treble fill, like the
one found here :
http://www.speakercity.com/clearance/clearance_drivers.shtml
sreten.
Should run off a 14V source (13.8) perhaps a touch more.
If its a 4 channel unit with bridged outputs should manage
~ 25W per channel into 4 ohms and theorectically 50W per
channel into 2 ohms if the the unit can handle the current.
Speaker design is presumably is about compact efficiency.
I'd suggest a combination of a small sixth or 4th order
bandpass and a sealed high efficiency unit for mid treble,
with possibly a extra tweeter driver for treble fill, like the
one found here :
http://www.speakercity.com/clearance/clearance_drivers.shtml
sreten.
If you deliberately tune a box too high you will end up with less LF extension but increased SPL for a narrow frequency range. That's one of the tricks some of the boomboxes use. I have two prototype boxes with Dynaudio 17W75LQ drivers. The tubes used for the ports can easily be removed. If this is done then there is a remarkable increase in bass-SPL at the cost of precision. Just play around with a box-simulation tool a little and you will see what I mean.
You should of course only do this if you want to have "boom". You should also use a highpass filter in this case.
If you want to go for quality you better leave it of course.
Regards
Charles
You should of course only do this if you want to have "boom". You should also use a highpass filter in this case.
If you want to go for quality you better leave it of course.
Regards
Charles
This is a good project!
My Sony head does not require much current at all....there is a 10A fuse in the panel for it and it has NEVER blown, no matter how hard I push it (but it sounds crappy anyway at high volume when it starts to clip), I have 6-ohm speakers in the doors, so power RMS could not be more than 20W or so per channel. You will definatly need to use lower-impedance speakers to get any power out of them because of their small rail voltages.
-Matt
My Sony head does not require much current at all....there is a 10A fuse in the panel for it and it has NEVER blown, no matter how hard I push it (but it sounds crappy anyway at high volume when it starts to clip), I have 6-ohm speakers in the doors, so power RMS could not be more than 20W or so per channel. You will definatly need to use lower-impedance speakers to get any power out of them because of their small rail voltages.
-Matt
A3rd.Zero said:I was thinking about a car head unit. Do you know what is typical current draw from a car head unit?
Phase_accurate: What?, Please explain.
Thank you
Milo
Hi Milo,
I'd expect static current to be quite low < 1 amp.
With typical efficiencies of class aB output stages and output
25W per channel clipping (x4) you can expect around 5 amps
average current drain, peak current ~ 10 amps.
sreten.
I would assume that using lower impeadence speakers would cause more current draw than the 6 ohm speakers you're currently using.
My personal opinion is that if you're looking to make a "hi-fi" boombox, I would probably stay away from the integrated amps in a car stereo headunit. However, it would probably be a great idea for the cd/radio portion of the boom box. Heck, you could even look for one of the double-din units that has a tape deck so you could really get that boombox effect
Maybe a decent headunit off of ebay + gainclones would equal something pretty dang tasty. Another option on the speakers is you could always have a foam bung or something to stuff the port to give you the "boom", with the option of removing it when you actually want it to sound decent
My personal opinion is that if you're looking to make a "hi-fi" boombox, I would probably stay away from the integrated amps in a car stereo headunit. However, it would probably be a great idea for the cd/radio portion of the boom box. Heck, you could even look for one of the double-din units that has a tape deck so you could really get that boombox effect
Maybe a decent headunit off of ebay + gainclones would equal something pretty dang tasty. Another option on the speakers is you could always have a foam bung or something to stuff the port to give you the "boom", with the option of removing it when you actually want it to sound decent
I like the idea of using the preouts and then using a gainclone or some such. It would be nice to use a head unit, which has the option of upgrading. I could even use one from the car and just plug it in when Im ready to go!
Ok now about the speakers, Im thinking something simple like the GR AV-1. I also like the idea of using a bg neo8 just for fun, but I dont know if I need a tweeter (not sure about its top end). Then the speaker boxes will in essence just be a woofer box, that might help get the low end.
Thanks for your help guys.
With ~2amps draw I guess i'm not going to try this with batteries, just AC on this one.
Milo
Ok now about the speakers, Im thinking something simple like the GR AV-1. I also like the idea of using a bg neo8 just for fun, but I dont know if I need a tweeter (not sure about its top end). Then the speaker boxes will in essence just be a woofer box, that might help get the low end.
Thanks for your help guys.
With ~2amps draw I guess i'm not going to try this with batteries, just AC on this one.
Milo
This year Panasonic makes an in-dash head unit using the new Texas Instruments digital amplifier technology. Described in detail here http://www.analogzone.com/avp_0105.htm. It is really efficient and provides 60 watts per channel of actual good clean RMS power. MXE CQ-C9800U.
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