* DIY Music Box *

[jimmyjimmy19702010]

Hi Guys,

Well I've spent the past 3 weeks working on a little project. I knew I wasn't breaking any new ground here when I decided to build my very own DIY noise maker. You know, one of those wooden monstrosities you see all over youtube.com where someone with some spare parts and a few bits of wood makes a box that produces music. I wanted it to have the basic shape of a large one piece boombox so that ruled out putting speakers into a plastic tool case or a suit case!! Something between an M9994 and M9998 in shape would do nicely.

I know, you're thinking: right? Well, you'll have to read to the end to find out what I ended up with.

My total budget for this project was a very limiting $100 AUD. I had some 7mm plywood laying about plus my sister had an unwanted old homemade plywood table made of structual 17mm ply. So I was all set, I had scrap ply plus an old table - I could smell success already!! Plywood also has the benefit of being much lighter than MDF although MDF is easier to work with.

For amplification I went with a very efficient $29 + shipping 12V D class TriPath amp with separate bass/treble controls on the front panel. Boasting 20 watts RMS per channel into 4 ohms, I assumed it would have enough juice to get things pumping.

For sound I found some local second hand 2012 Pioneer 6.5 inch drivers for $15 the pair. These units originally came with a remote mounted tweeter making them a 1 way driver. I preferred this arrangement as it would allow me to have a classic boombox style separate tweeter. I raided my parts pile and found a pair of tweeters from a parts Sanyo M9998K. To keep costs down, most of the internal wiring would also come from my dead Sanyo.

I had an old JVC PC-5 carry box laying about so I cut a side panel out of it to make a metal coated access door for the front panel of the DIY Box. I also robbed it of its' handle. This handle whilst old school quality, isn't your classic style of handle but it is strong and also free!

Firstly, after cutting some pieces of ply to size, I started the assembly process. The back panel, bottom piece plus the two amp support panels were the first to get glued and clamped:
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Next, the top panel was glued and clamped:
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I missed a few steps with the photos but here is the side panels glued and the front panel with holes drilled but still unattached (with speakers laying loose). As you may have guessed, I went with a sealed speaker box arrangement.
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I bit of prep now prior to priming:
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In primer waiting for the top coat:
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I used Satin black for the top coat - bad mistake. It looked horrible so I switched to flat black for a better looking finish:
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Everything wired up and tested OK:
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Next, paint the front access panel and install the volt meter:
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Almost there, just install the JVC handle and attach the Sanyo M9998K feet!
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Adding some sound deadening to the speaker boxes. The padding reduced the 'boom' but increased the 'bass' if you know what I mean:
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Size comparision between a Sanyo M9998K and the Panasonic RX-DT680: The DIY Box weighs in at 8.60kgs fully loaded which makes it slightly lighter than the Sanyo and Panasonic units:
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Quick sound test video:


If the above You Tube address disappears again, just go to Youtube.com and search for: jimmy diy music box and the video will be the first one on the page.

The sound output is best described as strong with crystal clear highs and solid, tight bass. There is no 'boomy' loose style of bass, more a controlled 'sharp hitting, punchy style of bass due in part to the sealed wooden speaker cabinets and sound deadening. It sounds more like a Mini System than a one piece boombox. The amp provides a very clean signal with no hiss evident at any volume level with no input signal. You can crank it right up to 3/4 volume before any clipping occurs (pretty loud).

Blue tooth is to be installed when funds allow. I'm also looking at attaching a strap.

I know it's not fair to compare old tech with new tech but I will say this thing is real strong with more RMS power than any of my boomboxes. After running the unit on and off for a few days, the volt meter reading has only dropped from 12.6 volts to 12.4 volts so battery life shouldn't be an issue!! I'd guess it would run for around 10-15 hours at max volume before a recharge is required but time will tell.

I'm not calling it a Boombox because it's not: It doesn't have a tuner, doesn't play tapes and isn't a classic but all in all, it was a fun project and I'm happy to add this one to the collection.

I'm taking it away for a long weekend with the family so I'll see how it performs in the real world.

Have a great weekend,

James.....

 

[im_alan_partridge]

Well done James, firstly how did you manage to keep this project quiet

You have put a lot of thought and effort into this unit and have come up trumps, it looks great and im sure it sounds great too.
You have got the balance just about right size and weight wise and with the rechargeable power supply installed it truly is portable.
And who needs a tuner, once you have the BT installed you can stream radio stations straight from your phone

 

[Beosystem10]

I have a Handover amp of similar type, I used that attached to the back of my PC-11 when it had its extra pair of speakers fitted to it and it drove those nicely. I've been thinking about creating some form of box in the style of Seasick Steve's instruments for a while now using that amp which, for the benefit of UK members who may fancy the idea too, costs £8.99 from a small shop on High Bridge down there in Newcastle 1, just off Grey Street. There's also a version with a built-in tuner chip too though that costs almost double but hey, these things are ridiculously inexpensive in every sense and it's good to see one fitted into an enclosure that isn't an old photographer's case or something with a Samsonite badge.

Nice job Sir! So impressive that I'm sure you can even be forgiven for hacking a rare PC-5 accessory to make it.

 

[jimmyjimmy19702010]

The You Tube video link keeps disappearing....?

If it disappears again, go to Youtube.com and search for: jimmy diy music box and it will be the first video on the page.

Thanks for the feed back guys!

James.....

 

[goodman]

Congrats for this good custom project!

 

[jimmyjimmy19702010]

I've just completed a sound quality/power comparison of the 'DIY' box and my heavy hitters. At low volume, the M9998K is in the race but as you crank them up, the Sanyo falls into distortion too early to be competitive. The RX-DT680 provides much more power and better bass than the Sanyo but as you turn up the volume, it can't quite match the power of the DIY box. From about 1/2 volume, the big Panny has pretty much given it's all.

'It's all about the bass, about the bass, about the bass no treble'

James....

 

[-GZ-]

Excellent work, jimmy. I've been wanting to do this since before I started collecting boomers.

 

[jimmyjimmy19702010]

Excellent work, jimmy. I've been wanting to do this since before I started collecting boomers.

Thanks man. Like everybody here, I love fixing old boomers by identifying faults, washing away the years of neglect from interior and exterior parts, rebelt jobs, reviving dirty pots and switches - super fun and very satisfying. Just seeing and hearing an old boomer come to life as a direct result of your own efforts sure is a great feeling!

But I've had an itch for sometime to build something from scratch. All the experience I've gained here at Boomboxery.com helped me to know what makes a good Boombox (IMHO). As a DIY project, you don't have access to complex plastic moulds, shiny chrome and trinckets. You just have to stick with the basics - try and get the size and weight ratio right, build it tough and do your best to make it sound good. It's also a great way to make use some of those parts you have laying around! Now don't get me wrong, it's a lot of work - I didn't show much of the work involved with the internal workings to get this thing pumping and the woodwork/sanding etc is very time consuming - but those 3 weeks of work have definately been worth it!!

Sitting back enjoying a beer with my wife Jenny last night listening to 'When the war is over' by Cold Chisel on the DIY box and thinking 'how good is this!'.

If you're thinking of building one, my advice is DO IT! It's the most Boomer related fun I've had in years and has definately rekindled my interest in portable music machines!!

James....

P.S Remember, there is a reason the HI FI guys use wood for speaker cabinets!

 

[jimmyjimmy19702010]

Hi Guys,

Well the DIY Box has been working really well. I got through an entire long weekend with hours and hours of blasting time and only ran the battery down to 50% charge - very happy with that.

The only issue I've run into is my second hand speakers. In short, the left one let go over the weekend. It always sounded different to the right one and the cone seemed to flop around more when the bass hit. So, I pulled out the wallet and ordered some brand new Pioneer speakers.
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I went with upgraded A series Pioneers this time with 14% bigger and deeper cones, bigger magnets, etc. Luckily, they went straight in with the same screw pattern - just had to remove a little sound deadening to allow for the bigger and deeper magnets.

The unit sounds stronger now - both channels now sound equal. The bass is deeper and much more controlled than before - very happy with the upgrade. With the heavier drivers, it has gained a little weight - now 9.40kgs. Although it's still lighter than my 10.00kg M9998K
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My wife actually prefers the look of the old ones but I know which ones sound better - anyway, it's obvious this box was never about the looks!!

Sounds awesome now!!

James....

 

[Beosystem10]

IMHO, that looks even better now than before but I'd be concerned about the battery losing half of its capacity after so little use.
My four year old Dell laptop's battery has been abused left, right and centre since the thing was new and still manages to reach nearly 77% capacity at 100% charge, indeed the slightly more sophisticated battery in my Google CR-48 - which was only ever intended to last the length of the original consumer test - still shows 100% at 100%. Maybe the battery you're using is short on capacity for the current it's being asked to provide and, as a result, has internal faults caused by overheating, maybe it's got a dead cell but either way, even if it's discharged below a sensible 7% and recharged fully on a quick charger it should maintain its full capacity for at least the first few dozen cycles.

 

[jimmyjimmy19702010]

Sorry John,

Just my incorrect terminology, I meant to say the battery ran down to 12.20 volts which equates to around 50% remaining charge on an SLA battery. After a recharge, the battery is back to 100% charge. I recharged my I Phone with the unit several times during the 3 day/night period too so the battery doesn't seem to getting knocked about too much!

John,

James.....

 

[Beosystem10]

Ah! I see. Well in that case it would appear that there is effectively no reason not to be insanely envious of your creation.

Do you plan to use the tweeters that came with the new speakers? I'm guessing that anything that can provide decent highs in the essentially less than ideal environment of a car interior would be crisp and detailed in a conventional(ish) enclosure.

 

[jimmyjimmy19702010]

I think I'll keep them for another project. It looks like the holes I cut for the Sanyo tweeters are too big for the smaller Pioneer tweeters. The Sanyo tweeters sound nice and clear in this application and seem to balance well with both sets of drivers.

James....

 

[JT Techno]

Cool - fantastic job James - you are giving me much food for thought - I'm expecting delivery of a new shed/workshop soon, so once I get it all kitted out, this is likely to be one of my projects too, once I've sorted out all my beater boomboxes that are waiting in line first

Out of interest, what type and spec of battery did you use?

 

[jimmyjimmy19702010]

Cool - fantastic job James - you are giving me much food for thought - I'm expecting delivery of a new shed/workshop soon, so once I get it all kitted out, this is likely to be one of my projects too, once I've sorted out all my beater boomboxes that are waiting in line first
Out of interest, what type and spec of battery did you use?

Hi,

I used a 12V 9.0Ah SLA (Sealed Lead Acid) battery:
Pros: High capacity, zero maintenance, no memory effect, cheap ($45)
Con: Weight

After testing, it appears I could have got away with a smaller 7.0Ah battery but it's nice to have the extra capacity, particularly if you want to recharge devices such as I phones etc from the internal battery (I've found this facility very handy).

If you keep the weight of the rest of the box down, an SLA battery is a good choice.
Tip: try to avoid the temptation of using a huge, power hungry amp. To have a practical runtime, you'll need a car battery to run it!

By the way, DIY portable audio can be addictive! I'm already planning my next one!

James....

 

[JT Techno]

Cheers James - good advice - and as if boombox collecting was not addiction enough - looks like multiple addictions is the way forward

 

[Beosystem10]

Cheers James - good advice - and as if boombox collecting was not addiction enough - looks like multiple addictions is the way forward

Sheds man, one's never enough! I got one some years ago and now it's so full of f*****g radios that the grass cutter has to sleep rough, the workbench has a dozen really interesting travelling folk living and operating a successful business on it and I know that my welding gear is under that lot somewhere.. Somewhere indeed!

My opinion of sheds, huts and but 'n' bens now? Crack, or even - God forbid - PRINGLES are less difficult to quit than secondary dwellings full of classic shiny things from lands far away!

Sorry James, 'bout the cutting in like that but he needed to be shocked into consciousness by someone who's been there, done that, worn the (creosote spattered) t-shirt and stapled my dangly parts to several lumps of timber.....

 

[metalhandbag]

Excellent work well done

 

[JT Techno]

Thanks Beo ... I concur ... and watch out for those dangly bits ... that's gotta smart a bit

 

[jimmyjimmy19702010]

Hi Guys,

Quick update on the DIY box for those who are interested

I've been using it for hours and hours of trouble free use and decided I wanted a 'tuner' for some fresh tunes.

Enter the $36 + shipping Bush 'Pocket' FM, DAB+ digital receiver that now provides an extra input for the DIY Box. The sound quality of this compact and lightweight digital radio is fantastic! 49 stations (many commercial free), crystal clear and great reception. I also use the Bush radio to provide a digital program source for the work van (the van radio has RCA inputs!!). As per the old Walkmans, this radio uses the RCA cables as an antenna when in headphone mode. It has a built in telescopic antenna if you want to use the inbuilt speaker (which sounds very tinny). The bass this thing pumps out when hooked up to the DIY box is amazing and really gives the Pioneer drivers a work out.

It has a removable Lithium Ion battery that recharges via a USB cable from the charging port on the DIY Box.

I also bought a $7 USB powered Blue Tooth receiver that I run from the charging port - works very well with a huge range and great sound quality!

Have a great weekend guys,

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