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Old 17th January 2007, 03:25 PM   #1
M3G4 is offline M3G4  United Kingdom
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Join Date: Jul 2006
Default mini boom box

Hey guys,

I was thinking of building an iPod hifi that would fit into my backpack using two 4" car coaxial drivers and a sonic T amp which is more than capable of driving them at their native 4ohm. Are there any pointers and anything I should take into consideration when making such a device? I say boombox, but I don't really want too much boom, just something cheaper and a bit better than the solutions offered today.

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Old 17th January 2007, 04:39 PM   #2
Buckapound is offline Buckapound  United States
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Join Date: Feb 2006
Location: Chicago, IL
Hoo boy, are you gonna learn a lot!

I've been working on my boombox for over a year. Starting to sound pretty good. Mostly cosmetic stuff to go.

You ask a huge question. Study up on the threads related to SI Mods and others. Here's my topline:

1. Do the mods, especially the C10 and stiffener cap upgrade, and new better input caps, if you want some bass.

2. Make it a great speaker cabinet. Rigid, correctly sized, ports well-tuned. In a small box, you may do better with a small inexpensive full-range driver such as the 3" HiVi. Study plans for cabinets built around these and similar (full-range forum) as a starting point.

3. Deal with the power supply issue. Elsewhere on this forum recently has been some good descriptions of using surplus lithium computer batteries to power these amps. Lead-acid are reliable, but HEAVY.

4. Consider a line level circuit (baffle step compensator) to get a more balanced sound out of the small speakers. I just built a simple but effective one by Paul Joppa on www.t-linespeakers.org. If you breadboard it you can adjust the parts values to your particular speakers.

Here's what mine looked like a few months ago before I cleaned up some of the metal work.

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Old 17th January 2007, 10:13 PM   #3
toolkit is offline toolkit  United Kingdom
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Join Date: Nov 2006
Location: Chesterfield, UK
Originally posted by Buckapound
[B]Here's what mine looked like a few months ago before I cleaned up some of the metal work.
That looks awesome....any more details online anywhere?

But dammit...now that's on my list of to-do things

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Old 18th January 2007, 12:51 PM   #4
Buckapound is offline Buckapound  United States
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Join Date: Feb 2006
Location: Chicago, IL
Nothing yet. I'll post to Panomaniac's TriPath gallery when I get new pictures. Here's the gist of it:

- 2 SI boards, fully modified, new caps, inductors, etc. (one for outboard speakers)
- CSS FR125s 4" drivers. Man, do these sound great! (TangBand Bamboos shown in pic, but since replaced)
- Three ports: front and each side (not done on poster pic)
- 7 AH SLA battery, computerized charger/maintainer
- 13.2v LED monitor supply
- Line level baffle step filter for more bass/reduced mids (adjustable bass boost)
- Box made of 1cm thick fiberglas/carbon fiber/nomex aerospace honeycomb panels
- Decorative outer shell of carbon fiber
- Hand-fabricated stainless hardware (bottom, corners, handle, etc.)
- Custom-turned knobs, flared port, adjustable feet w/butyl inserts)
- Built in 5v USB power supp. (to charge iPod)
- Blue LED inside front port
- Weight, approx 30 lbs/18kg!

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