Backpack Sound System

[patinsdalinha]

Hello,
I'm the founder of a portuguese inline skating group (with some regular tours in Lisbon) and I wanted to build a sound system backpack.

I have a few photos from other backpacks:
http://www.patinsdalinha.com/forum/viewtopic.php?t=221
I was thinking something like in the last photo.


The problem is that I do not know anything about audio, batteries and electronic... but if you help me giving me some tips I could ask someone that knows something to help me build.

Thanks in advance for your help!

[Cal Weldon]

Now those are some people after my heart. I have fooled around with that sort of thing before but never to that extent. I love those people. As far as what they are using you'll have to ask some others that might have done it. What a great idea, sorry I couldn't help much. Are they using ipods for their source do you know? It looks like some lighweight car audio stuff and some sort of battery arrangement. I wonder if the are using lithium batteries. If you are building the cart version, it should make it easier as you don't have to lug the batteries around. And there's a spot to keep your beer.

[Pano]

That's cool stuff!
This subject has been talked about a bit on the Class-D forum for bicycles and other portable audio.

Class-D amps are a good choice, as they are very efficient and thus will not need as big a battery for a given power/run time.

Automotive sound gear is the natural choice, as it is small and made for battery use. But most car speakers are very inefficient. Getting more efficient speakers will help your system overall. You'll need less power for more sound. Always a good thing!

There are certainly people here who can help you choose the right drivers. The amp might be a little more difficult.

This is fun; let's see what the forum comes up with.

[bigwill]

A couple of high efficiency 8" eminence drivers with tweeters would work quite nicely for the speaker side of things

[patinsdalinha]

As I have told you before I don't understand anything about electronics and audio stuff...

If you could help me giving some links to pictures or sales of the examples you say it will help a lot.

The cart version is an option... but if possible I would go for the backpack.

Thanks in advance!

[Pano]

What is your budget for the electronics part of it?
You know, the speakers, the amp, the battery.

That way we can point you to items that will work within your budget.

Also - what is your final quality goal? Do you just want something loud with BIG BASS, or do you wish a more balanced, quality sound?

[Saturnus]

You might wanna check this thread out.

DIY: SI T Amp Boombox, FR Speaker Selection

Especially the Podzuma design from part express (link on page 3) has definate promise for your purpose.

[Pano]

The Podzooma is cool, but i can tell you - that Sonic Impact amp is NOT going to have enough power. In stock form it is rather bass shy. You can see my site to understand what I'm talking about.

Other than that, the Podzooma concept is cool. But a nice car amp with 50 watts or more would be better suited, IMO.

[Saturnus]

I already have check out your site, and have a running "stealth modded" model running fine at home.

But I assure you that it does pack enough punch provided the speakers are relatively effective. The 10" drivers I use are around 96 db/watt/meter. With 2 of these in parallel the Sonic T provides more than adequately power.

Granted 10" driver are probably too much to "sling on your back" in a hurry but the Podzuma design does give around 94 db/watt/meter IIRC, or around 108 db before clipping, and that should be enough for even party hard people.

EDIT: Oh, and btw, if it's running from an iPod or Zen I would actually recommend using a non-modified version of the Sonic T amp as both iPod and Zen are a little "bass heavy" when used to feed the Sonic T. I suspect that's why they the Sonic T's slightly "bass light" to begin with.

[patinsdalinha]

Originally posted by panomaniac
What is your budget for the electronics part of it?
You know, the speakers, the amp, the battery.

That way we can point you to items that will work within your budget.

Also - what is your final quality goal? Do you just want something loud with BIG BASS, or do you wish a more balanced, quality sound?

I don't know like around... 150€.
The goal is to have sound in our skate tours around the city. It doesn't have to be VERY LOUD... but it would be nice that skaters who aren't close to the sound system could hear it.

Thanks in advance for all your help!