Want to build a portable ipod boombox.

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#44
I looked at a couple of those boosters the other day but the ratings on them are more about instantaneous current 300-500A as they are used for starting but I intend to do some googling and see if I can find an AH rating. I would bet that the larger ones are pretty decent. The one I look at claimed something like 8 hours for a radio if I recall correctly so it might just work.

mike
 
#47
SI claims 12hours from AA battery power. Best case scenario at very low volume of course. But an AA battery is not even close to 9ah. An AA battery probably only has 1.5ah? NiMH batteries are only up to 2.5ah. And, it cost less then $40 and is inherantly portable. Great portable power solution. It doesn't add bulk or wieght when using AC power either.
 
#48
Instead of starting a new thread, I thought I'd resurrect this one...

I've got almost everything I need now

Loads of Li-ion 18650 cells prised from old laptop battery packs.
Made into 24v packs for my amp9 kit. Works great when up to my home speakers.

I've also got loads of 1/2" ply.

All I need now is crossover components and drivers and I can make a start.

If I was to use drivers with a rubber surround and a poly or alu cone, would the driver be water resistant?

It rains a lot in the uk, and I'd like to be able to use it outside.

Also, I'm only going to be needing a signal 100Hz and up... so can anyone suggest a good driver? I'm tempted to go for 4 x of those MCM 4" Alu full range drivers, but I'm sure there are better things out there, probably with a neo magnet (higher sensitivity).

The electronics side of it I'm more than happy enough to build, it's only the whole speaker side of it I struggle with... Can winISD model the isobaric 4x driver configuration?
 
#49
MikeHunt79 said:


Loads of Li-ion 18650 cells prised from old laptop battery packs.
Made into 24v packs for my amp9 kit. Works great when up to my home speakers.
Click to expand...


This is more than interesting. Do you have a digital camera? I am asking this because what you are doing is really worthy of a completely new thread, in which you show us, in pictures, how you obtain all these batteries, disassemble them and put them back together again, to make a 24V power pack. And also the entire project, from start to finish.

If for no other reason making it as clear as possible would stimulate others to do the same thing, when it would not occur to them, or would seem to be daunting. That is why I am recording my experience with the hexagon enclosures here in this section. Pictures are worth more than a thousand words.

If I was to use drivers with a rubber surround and a poly or alu cone, would the driver be water resistant?

It rains a lot in the uk, and I'd like to be able to use it outside.
Click to expand...

Rubber surrounds and a protected cone would go a long way toward making it water resistant. But remember this, there is a Huge difference between "water proof" and "water resistant. The former would not be worth the effort in this first attempt IMO.

Let's assume that you are going for the best water resistant device possible. You have more than just the speakers to worry about. If you seal the dust cap, and the joints around the speakers, you can eliminate any leakage of water into the box, from the speaker end.

The next thing would be to make it more than difficult for water to drip, or even fog up the insides of the box. This means that the solid part of the box would have to be completely sealed, by caulking and finishing it with a nice finish that will repel all water. That is doable.

What is more difficult is when you attempt to seal the removable panels to get into the box. This includes things such as changing the batteries, controling the amp by knobs and switches, etc. This is the weakest link in the goal of the project.

Constructing a panel for servicing the batteries can also be bullet proof, by completely sealing the panel inside and out, and using a one piece rubber seal inside to keep out any moisture. If it's not one piece, the place where the two ends meet will be open to allow moisture in.

And that leaves the controls part of the box. Definately placing the controls on the top of the box is a recipe for disaster. You will have to make it as hard as possible for water to get to it, knowing that it is a losing proposition, if you are not willing to make some compromises. So, you will most likely have to set up the control panel on the side of the box, with an overhang to channel any dripping water away from the controls. You can also route a small recess around the control panel, with the recess coming to a point above it. That way, gravity will cause dripping water to enter the recess and be channeled out and down, away from the panel cover. Then all you will need is some kind of cover, probably a clear plastic, which also has a one piece rubber surround and a quick latch for sealing it from the elements.

If you give it some thought, you should be able to come up with an attractive box, and one that you can carry with you everywhere, and not be particularly worried about damage. And if some water does get in the box, a nice hair dryer blowing into the innards can get it out fairly quickly, provided you do that at the earliest available opportunity. I had that happen to my new cell phone. I got caught in a torrent last summer and was talking to someone while trying to get out of the rain. It still got moisture inside the phone, but by loosening the case and turning on a hair dryer to it for several hours, I managed to get rid of the moisture.

Also, I'm only going to be needing a signal 100Hz and up... so can anyone suggest a good driver? I'm tempted to go for 4 x of those MCM 4" Alu full range drivers, but I'm sure there are better things out there, probably with a neo magnet (higher sensitivity).
Click to expand...

I'm not up to speed on which ones would work best, but I would recommend that you seek the driver with the best sensitivity, since you are driving them with a less robust amplifier and using batteries. That still should not be all that daunting.

Do you have any woodworking experience?

The electronics side of it I'm more than happy enough to build, it's only the whole speaker side of it I struggle with... Can winISD model the isobaric 4x driver configuration?
Click to expand...

I'll let others help you out here.

Hey, this is a great idea! If you sit down and think this out, you should be able to come up with a doable design that is functional AND attractive. If you need the services of a woodworker, I will bet you that there are many in UK who can offer their services.

I think you could make this into a super thread, if you are able to record your progress with pictures and wish to take the time to do so.

Just think of all the positive attention you will get? 😀 😉


Note: Here is my first set of questions for you.

1. How do you go about getting all those computer batteries?

2.Are the easy to pick up at any computer store? Are they thrown away and tossed out, where anyone can get them for nothing, or little to nothing?

3. Also, when the batteries go bad, is it usually just a few cell packs that are bad, and the rest good? If you can check the bad pack and salvage several good cells from several batteries, you can easily come up with great remade batteries. 🙂 I would think that some parts of the battery would go bad well before others.

4. Are the batteries fairly easy to break down and canibalize?

I think that is a good start. This is a Great Post!! Keep up the good work.
 
#50
John L said:
This is more than interesting. Do you have a digital camera? I am asking this because what you are doing is really worthy of a completely new thread, in which you show us, in pictures, how you obtain all these batteries, disassemble them and put them back together again, to make a 24V power pack. And also the entire project, from start to finish.

If for no other reason making it as clear as possible would stimulate others to do the same thing, when it would not occur to them, or would seem to be daunting. That is why I am recording my experience with the hexagon enclosures here in this section. Pictures are worth more than a thousand words.
Click to expand...
Well, I've been meaning to get something done for a while now, but now I have some spare time after christmas to build! :smash:

I do have a digi-cam, and I'll grab some shots today if I can... I've got to head out now, but I should be able to post some later. Basically, 18650's in most laptop battery packs are wired in pairs, giving 3.7v @ 4800mah. I simply wired a load of these in series to get 22.2v, which is perfect for powering the 41hz.com amp9 kit. 🙂
John L said:
Rubber surrounds and a protected cone would go a long way toward making it water resistant. But remember this, there is a Huge difference between "water proof" and "water resistant. The former would not be worth the effort in this first attempt IMO.

Let's assume that you are going for the best water resistant device possible. You have more than just the speakers to worry about. If you seal the dust cap, and the joints around the speakers, you can eliminate any leakage of water into the box, from the speaker end.

The next thing would be to make it more than difficult for water to drip, or even fog up the insides of the box. This means that the solid part of the box would have to be completely sealed, by caulking and finishing it with a nice finish that will repel all water. That is doable.

What is more difficult is when you attempt to seal the removable panels to get into the box. This includes things such as changing the batteries, controling the amp by knobs and switches, etc. This is the weakest link in the goal of the project.

Constructing a panel for servicing the batteries can also be bullet proof, by completely sealing the panel inside and out, and using a one piece rubber seal inside to keep out any moisture. If it's not one piece, the place where the two ends meet will be open to allow moisture in.

And that leaves the controls part of the box. Definately placing the controls on the top of the box is a recipe for disaster. You will have to make it as hard as possible for water to get to it, knowing that it is a losing proposition, if you are not willing to make some compromises. So, you will most likely have to set up the control panel on the side of the box, with an overhang to channel any dripping water away from the controls. You can also route a small recess around the control panel, with the recess coming to a point above it. That way, gravity will cause dripping water to enter the recess and be channeled out and down, away from the panel cover. Then all you will need is some kind of cover, probably a clear plastic, which also has a one piece rubber surround and a quick latch for sealing it from the elements.

If you give it some thought, you should be able to come up with an attractive box, and one that you can carry with you everywhere, and not be particularly worried about damage. And if some water does get in the box, a nice hair dryer blowing into the innards can get it out fairly quickly, provided you do that at the earliest available opportunity. I had that happen to my new cell phone. I got caught in a torrent last summer and was talking to someone while trying to get out of the rain. It still got moisture inside the phone, but by loosening the case and turning on a hair dryer to it for several hours, I managed to get rid of the moisture.
Click to expand...
Yep it certainly sounds like quite a challenge. I'd be happy to be able to use it in the rain without worry... I won't need to make it work underwater or anything like that. :hot:

I was thinking about maybe building a box out of 4mm plexiglass instead of wood, but I think wood when varnished should be just as water proof.

I find access panels can be sealed quite well if you use weatherstrip, as if it's airtight I guess it should be watertight also.. As for controls and things, I'll cross that bridge when I come to it. I'm tempted just to have a 3.5mm recessed socket, and use the ipod/mp3 player for volume control.
John L said:
I'm not up to speed on which ones would work best, but I would recommend that you seek the driver with the best sensitivity, since you are driving them with a less robust amplifier and using batteries. That still should not be all that daunting.

Do you have any woodworking experience?

I'll let others help you out here.
Click to expand...
So for I've only built the "AutoTuba" which is a folded sub horn. It's rather large compared to portable boombox, but I'm pretty confident working with ply. I hate MDF tho, it's the work of the devil. 😉
John L said:
Hey, this is a great idea! If you sit down and think this out, you should be able to come up with a doable design that is functional AND attractive. If you need the services of a woodworker, I will bet you that there are many in UK who can offer their services.

I think you could make this into a super thread, if you are able to record your progress with pictures and wish to take the time to do so.

Just think of all the positive attention you will get? 😀 😉
Click to expand...
Check out the "boominator" thread if you haven't already - I'm certainly not the first to attempt this sorta thing. 😀
John L said:
Note: Here is my first set of questions for you.

1. How do you go about getting all those computer batteries?
Click to expand...
ebay - I simply went for untested battery packs, but all the cells I got hold thier charge. I guess it could have been lucky.
John L said:
2.Are the easy to pick up at any computer store? Are they thrown away and tossed out, where anyone can get them for nothing, or little to nothing?
Click to expand...
You may be able to pick them up for nothing - people often throw them out then thier laptop battery only lasts for 1 minute or so. this could be down to 1 dead cell out of 8, so once the cell are removed, you still have 7 good cells.
John L said:
3. Also, when the batteries go bad, is it usually just a few cell packs that are bad, and the rest good? If you can check the bad pack and salvage several good cells from several batteries, you can easily come up with great remade batteries. 🙂 I would think that some parts of the battery would go bad well before others.
Click to expand...
Yep, you got it. I often cycle the batteries to check thier capacity, as all Li-ion batteries start loosing capacity from new, weather they are used or not. I then make a pack from the ones with the best capacity.
John L said:
4. Are the batteries fairly easy to break down and canibalize?
Click to expand...
You've got to be careful not to cut into the cells when breaking the pack apart, they could short out and even explode! :hot: I try not to use anything metal to open the packs... They often are held together with clips or glue. Be careful tho, don't try it if you don't know what you doing.
John L said:
I think that is a good start. This is a Great Post!! Keep up the good work.
Click to expand...

Gotta go now, I'm already late for work. :devilr:

For more info on 18650's, loads of people over at candlepowerforums are using 18650's to power torches (flashlights) - They have a whole section dedicated to batteries, so there is loads of good info over there. It's where I learned about the whole laptop battery thing.

Finally, 1 18650 cell is 3.7v at 2400mah, and weighs less than a Ni-Mh AA cell (1.2v @ 2500mah). So around 3 times the power and less weight, and also no memory effect and Li-ions don't loose charge when not in use.

Li-ion is the way to go for a DIY boombox tho, as long as it is done safely. If you are unsure about anything, pick up some protected cells from batteryspace.com instead. 🙂
 
#51
MikeHunt79 said:
Gotta go now, I'm already late for work. :devilr:

For more info on 18650's, loads of people over at candlepowerforums are using 18650's to power torches (flashlights) - They have a whole section dedicated to batteries, so there is loads of good info over there. It's where I learned about the whole laptop battery thing.

Finally, 1 18650 cell is 3.7v at 2400mah, and weighs less than a Ni-Mh AA cell (1.2v @ 2500mah). So around 3 times the power and less weight, and also no memory effect and Li-ions don't loose charge when not in use.

Li-ion is the way to go for a DIY boombox tho, as long as it is done safely. If you are unsure about anything, pick up some protected cells from batteryspace.com instead. 🙂 [/B]
Click to expand...

Great information. If you could provide the links to the Boomerator, and also what you type in for getting all this at E-Bay, it could help others better.

Also, I totally agree with you about the Li-ion advantage. I just recently purchased a Black & Decker cordless drill with Li-ion battery, and will never go back to those Ni-Mh batteries again. They don't retain a charge, and are much heavier. I also have the Ryobi 18V "One" system, and Ryobi has thoughtfully adapted their new Li-ion batteries to the system. I fully intend to switch over to the Li-ion replacement batteries($99.00 for two batteries and a special charger) very soon, and use the Ni-Mh batteries with my flashlights.

I'll never buy another tool that does not use Li-ion batteries, unless they come up with something better. No moving backwards for me in the portable tool business. 😉

Again, a really great and informative post. Congratulations!! Keep it up.
 
#53
John L said:


Great information. If you could provide the links to the Boomerator, and also what you type in for getting all this at E-Bay, it could help others better.

Also, I totally agree with you about the Li-ion advantage. I just recently purchased a Black & Decker cordless drill with Li-ion battery, and will never go back to those Ni-Mh batteries again. They don't retain a charge, and are much heavier. I also have the Ryobi 18V "One" system, and Ryobi has thoughtfully adapted their new Li-ion batteries to the system. I fully intend to switch over to the Li-ion replacement batteries($99.00 for two batteries and a special charger) very soon, and use the Ni-Mh batteries with my flashlights.

I'll never buy another tool that does not use Li-ion batteries, unless they come up with something better. No moving backwards for me in the portable tool business. 😉

Again, a really great and informative post. Congratulations!! Keep it up.
Click to expand...
Boominator thread - http://www.diyaudio.com/forums/showthread.php?s=&threadid=104402

Not exactly lightweight as he's using 4 x 10 inch drivers and sealed lead acid batteries. It should have a good amount of bass tho. 🙂

I'm pretty much decided on 3" or 4" drivers, and want 100Hz and up, as I can cross this with a sub when I'm in the house, and I can even power the sub with the amp9 as it a 4 channel unit... 🙂

An active crossover is another thing on the to do list... Also, I'll get some battery pics asap... 🙂
planet10 said:
Some of its attributes might not be best suited for a boom box but the Fostex FF85K is really good sonically.

dave
Click to expand...
Thanks, I'll check it out... Ideally I'd like something that sounds good, and durable, so I'd like to avoid foam surrounds and paper cones really. Also 4 ohms is nice as my amp9 work better with 4 amp loads compared to 8 ohm loads. 🙂

I've been reading about the Monacor SPH 30x, and it has a kevlar cone which I've never seen before... Would this be as water resistant as say, a poly cone?
 
#55
car speakers

have you considered using good quality car speakers?
Click to expand...

John, I was wondering the same. I've been toying with the idea of making a pair of inexpensive outdoor speakers with coaxial drivers. these won't have quite the same design constraints as a boombox, but share the need for durability and weather resistance. The first major roadblock to using car speakers appears to be a real lack of published T/S parameters!

PS Madisound has had a sale running on several Audax coaxials (4-in, 5.25 in). I haven't checked to see if they are still available.

Anyways, this is a great thread!

Squib
 
#56
John L said:
This may be going against the grain, quality wise here. amongst some members, but have you considered using good quality car speakers? Many of them are made to be weather resistant, and some are of particularly good quality. And most of them are within the single driver format.
Click to expand...
I actually have some infinity 6"x9"s gathering dust right now... They have poly cone, rubber surround, and are 4 ohms... they are almost ideal!

I doubt they'd be as hifi as the monacor driver I was looking at as it has a passive crossover, and they may be be quite as sensitive as they don't have a neo magnet, but they've got a higher power rating and should give more bass. 🙂

If I can find some T/S parameters, I'll start WinISD'ing a box. 🙂

Great idea btw - I should get some battery pics up today, even tho I'm a little hungover: :dead:
 
#57
right Squib, I have closeout car speakers set up for my one pair of my computer speakers. They are closeouts over at Parts Express, and include a 5 1/4" main driver and a dome tweater, along with crossover.

An externally hosted image should be here but it was not working when we last tested it.


Here is what mine look like, done in teak and finished in shellac. Nothing spectacular, but they look nice and sound quite nice too as long as you are not looking for a great deal of low end. A small sub would work well with them.

ReconstitutedTeakspeaker3Resized.jpg
 
#58
MikeHunt79 said:

I actually have some infinity 6"x9"s gathering dust right now... They have poly cone, rubber surround, and are 4 ohms... they are almost ideal!

I doubt they'd be as hifi as the monacor driver I was looking at as it has a passive crossover, and they may be be quite as sensitive as they don't have a neo magnet, but they've got a higher power rating and should give more bass. 🙂
Click to expand...


Remember, you will be operating this box in an open aire environment and worrying about T/S parameters may not be all that important. Car speaks are more geared toward the infinite baffle, which this project would be made for. If you try to come up with something that is geared to work in your room, you may well be defeating your purpose. I wouldn't worry about modeling things for this job.


Great idea btw - I should get some battery pics up today, even tho I'm a little hungover: :dead:
Click to expand...

What is it with you blokes and your drinking proclivities? Your body is trying to tell you something there. Luckily the older you get, the more you will begin to pay attention to what it is begging you not to do. 😉

More info into the Brit's strange mating habits.
 
#59
I managed to get a quick piccy, I've even got the grills. 🙂
An externally hosted image should be here but it was not working when we last tested it.


They're infinity 692i's, and I can't find the T/S parameters anywhere! 😱
John L said:
Remember, you will be operating this box in an open aire environment and worrying about T/S parameters may not be all that important. Car speaks are more geared toward the infinite baffle, which this project would be made for. If you try to come up with something that is geared to work in your room, you may well be defeating your purpose. I wouldn't worry about modeling things for this job.
Click to expand...
Ok, I see your point. It would be nice tho for this to sound good indoors... and vented will definitely give better bass than sealed.

I'm tempted to just made and box, just guess the port and box size and see how it sounds. As you say, outdoors it won't make a huge difference. 🙂
John L said:
What is it with you blokes and your drinking proclivities? Your body is trying to tell you something there. Luckily the older you get, the more you will begin to pay attention to what it is begging you not to do. 😉

More info into the Brit's strange mating habits.
Click to expand...
😱 The worst thing is I actually live in Bristol, so I recognise most of the places in that Daily Mail article. :dead: Thankfully I don't recognise any of the people tho... 😀

I am starting to get to that age where I'm up not up all hours, but that being said, I'm off out again in a minute...

Anyway, back on topic, I managed to get you a pic of some 18650 Li-ion cells and a laptop battery pack that has just been ripped open :devilr: The flash screwed up the exposure a bit tho... 🙁

EDIT: The black thing of the left is a DSD charger - it will charge cells at about 800ma when combines with a Nokia ACP-12x mobile phone charger. 🙂

I plan to use 3 x DSD chargers... I charge cells 1,3,5, then when they are fully charged, I charge cells 2,4,6.

I keep meaning to make a multi-core cable to make this quicker to do, or get some sort of pack charger. 🙂
 

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