Portable Hifi driver suggestions

[TEH725]

I am not sure if anyone can help me but I thought I would ask. My current portable hifi is primarily made up of three enclosures housed in a simple plywood box. I can use it as a self-contained boombox or I can pull the drivers out to get better imaging. I use this on my deck, when I go camping, etc. The source is an iPod with a t-amp that puts out about 8 good watts into 8 ohms. The three drivers are two modified Minimus 7 (Zilch mod if you are familiar) and a Cambridge Audio passive sub. Power source is an SLA battery.

It actually does not sound too bad and it will play all weekend. But, it has 3 design flaws – it’s pretty heavy, it’s not loud enough (for some situations) and it’s a little bulky (about 12H X 9D X 24W).

For my next venture, I found a 2050 based t-amp on ebay that has a separate chip for the sub channel. With 20v power, it says it will output 30 watts into a 4 ohm load to the main drivers and 40 watts to the sub. It also has a separate bass, treble and sub controls as well as a master volume control. I have played it using an 18v drill battery into 89db 8 ohm full range speakers and the CA passive sub and it does not sound too bad given that I can tweak everything using the controls. Still not loud enough so I thought I would try 4 ohm drivers.

To make a too long story short, I am looking for small full range drivers and a small sub driver to build into a multi cabinet unit that can be used as a boombox or small system with detachable speaker/sub/amp unit. My budget is around $50 per driver.

Here are a couple of drivers I have considered for the main speakers:

4 ohm:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=292-518

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-828

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-913

Some 8 ohm:

http://www.madisoundspeakerstore.com/approx-4-fullrange/fostex-fe126en-4-full-range/

http://www.madisoundspeakerstore.com/approx-5-fullrange/aurasound-ns525-255-8a-5.25-paper-cone-8-ohm/

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-916&utm_source=google&utm_medium=cpc&utm_campaign=pla

Sub:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-919

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-831

http://www.ebay.com/itm/290734609719?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Any suggestions are appreciated.

 

[xrk971]

Have you looked at the Boominator thread in the class D forum? For outdoor use you should look into bipole designs like Boominator. High efficiency 92 to 95 dB drivers are helpful so PA style drivers may work. The Visaton driver fr13 is a super high Qts driver suitable only for open baffle.

 

[TEH725]

I have, but that thread is a bit intimidating given it's length. I don't want to mess with Xover design, so I am sticking with full range for now. I will check out the PA drivers as a option though.

I found a Visation full range in another thread that is 97 db efficient for $20 from MCM. Might be worth a look.

 

[TEH725]

BTW, xrk971, love your work on the spiral. It encouraged me to experiment with foam board!

 

[chris661]

I'd strongly advise against such low-efficiency bass drivers: they have lots of excursion, and thus lots of potential for output. However I can say from experience that the Tang Band mini-subs need a rocket up them to come to life. I clipped a 120w/ch amp into mine and they asked for more.

As you won't have that sort of power available, I really wouldn't bother. They're great for computer use, where you have a wall socket nearby, and will happily go into a small cube under the desk, and consume all the power you want to throw at them. Low bass plus small size = low efficiency.

What you're after is high efficiency (reduces battery requirements massively) and small size (or you won't be able to carry it), so low bass performance must suffer.

Get an 8" PA midbass, use that for subwoofer duties until around 200Hz, then cross (actively!!) to a couple of high efficiency 3" mid-tweeters, eg the Fostex FE83s.

The trick is to forget anything below around 80Hz, and make the 90-150Hz range kick you in the chest. Your brain will fill in the rest.

Chris

 

[TEH725]

Thanks, I wondered about those bass drivers in the 80-85 db efficiency range.

I wonder what is in the Cambridge Audio sub I am using now? I think I get into the 50s with that. I may just reuse it. It is not the reals source of the weight. Its mostly the SLA battery and the Minimus 7's combined.

Last weekend I hooked the amp up to a single 18v battery, the CA sub and some 5" Tang Band 89db efficient full range drivers. It sounded pretty good. Still not quite loud enough. I only had to turn the sub volume control to about 12 oclock in this setup.

I will keep fiddling, but I may have to settle for a little lighter, a little smaller and a little louder.

 

[chris661]

Where abouts in the UK are you?

I'd be happy to demo my current boombox to give you a feel for what can be done for ~£100.
I'm currently using a pair of 8" midbass drivers, plus some KEF 3" coaxials, and a pair of 15w/ch amplifiers, plus 12v @10Ah of batteries.
Its not light (I'll be installing wheels some time soon so I can wheel it like a suitcase), but can get rather loud if needed.


Chris