Help matching a amp to a speaker (building a large portable sound system)

Hi all

I am working on a little side project and need some help finding a suitable amp for a speaker I have.

The speaker is a Gemini gx400 manual here: http://www.manualslib.com/manual/60344/Gemini-Gx-300.html?page=10#manual

in short
300W RMS
1000W Peak
8 ohms

As it is built on one speaker it only needs a mono amp and as it is portable it needs to be power efficient, so a class D preferably.

My research has led me to two items:
A 300W amp: http://www.sure-electronics.net/down..._Ver1.0_EN.pdf
A 600W amp: http://www.sure-electronics.net/down..._Ver1.0_EN.pdf

I read that you lose power as the amp is made supporting 4 ohms and the speaker is 8 ohms it could lose up to 50% of its power, so that's why I am thinking about getting the 600W version. Also it's less likely to start clipping and it's ebay page says it can do 200W @ 8ohm < 0.40% THD+N.

So does any one understand what I just said? and do you have any other suggestions for a amp that can be battery powered?

Bike trailer soundsystem?

indeed it is

A forum I was a member of has a chap does this using car batteries and car speakers for critical mass and the like.

http://www.bikeology.net/

I've messaged him

Cheers.

That's one hell of a system he's got there.

Wattage ratings are pretty much meaningless.
What you want to be looking at is sensitivity. 109 dB/w/m is very high. At 1m 1watt will give you 109dB. That is pretty dammed loud.
I would just buy a cheap 20-30w class-t amp. They are very efficient and will easily run off batteries.

All depends how loud you actually need it to be...

There is a useful calculator towards the bottom of the page here http://www.sengpielaudio.com/calculator-efficiency.htm

Plugging in some numbers.

Assuming the sensitivity is correct at 109 and assuming you are using 10w of power from the amp and that you are 20m away the SPL would be around 93dB!

This is free field, if there is a wall behind the speaker it will be more, and more again if it is in a corner.

If he doesn't answer, shout as I saw him today and will see him on thursday.

He tried logging on here so to quote

any class D full range amp should do it. Sounds to me like a basic user so not after kit amps etc so I suggest using something like Vibe Litebox, Alpine PDP etc.

Someone could have said the links didn't work

300W amp: http://www.sure-electronics.net/download/AA-AB31191_Ver1.0_EN.pdf

600W amp: http://www.sure-electronics.net/download/AA-AB31241_Ver1.0_EN.pdf

do you think these are suitable ? I am leaning towards the 600W version.