Eminence Alpha 6 - Good Choice for Boombox?

[DunkH]

Hi,
Well the subject describes it really,

I'm thinking of building a boombox. Using an Amp 6 kit from 41hz, this puts out around 25w per channel from 12volts into a 4ohm load.

I want a good combination of efficiency, bass response and price as well as a 4ohm voice coil (although I suppose 8ohm driver would be ok if the efficiency is very high) .

So far the best choice appears to be the Eminence Alpha 6 drivers(4ohm), these are 6" and with a 10l ported box I think I can get a -3db point of around 90hz. They have a high efficiency of around 93db.
http://www.eminence.com/pdf/alpha-6c.pdf

Does this seem like a good choice or are there other speakers I should look at?

I'm in the UK by the way so I would need to be able to order these from somewhere failry local, perhaps France or Germany as well.

Thanks!

[chris661]

From the alpha range, I wouldn't go lower (size) than the 15.

I used the 10 and that didn't go low at all. Your idea of going to 90Hz won't help you much either - bass drum in rock is around 40Hz, dance/club music has it's thuds around 60-100Hz.

Is this for a car project or at home? What's the budget? What's the box size (max)?

Tip - download winISD beta, put the speaker's parameters into it, mess around with box sizes.

And no worries about ordering - I only know of UK dealers (I'm 15 so getting shipping won't be easy).

Chris

Quick driver recommendation - http://cpc.farnell.com/_/55-1455/dua...r-8/dp/LS00415

I can get you the parameters aswell if needbe.

[DunkH]

Hi,
When I mean a boombox I mean a portable system, battery powered. The sort of thing everyone had in the 80s. Also known as a ghettoblaster!

I have seen a guy who has made one on wheels with a 15" driver but thats way to big for what i want!

I'm really looking for something to take camping or to the park, or for the garden.

I'm a big fan on dub and reggae and completeley understand that a lot of music has 40hz tones in but I dont think that will be practical for something portable, or at least not at loud volumes.

Thanks for the link, I didn't think about farnell / cpc. I will have a look at their site now.

Cheers

ps I did use winisd to get the 90hz figure

[kipman725]

http://www.rapidonline.com/productin...77868#techspec

Rapid have the Alpha-8 which claims to go down to 65Hz

Also aslong as you get the first harmonic (double the frequancy of the fundimental) of a note the brain thinks that it heard the fundemental so you shouldn't miss that much. In previous boom box threads I think what was percived to be a very good unit only went down to 100Hz.

[DunkH]

Hi,
That makes sense about the harmonics, anything natural sound or anything electronic that isn't a sine wave will have some harmonics so should ound ok.

I have found a beyma driver BEYMA-8-AG N that looks quite good:

http://www.hifisound.de/oxid/oxid.ph...b2f63.70370152

Its 4ohm, full range and 96db efficient which is spot on.

Pro audio parts do the 8ohm version for £16 ! I think I need to see if they can get the 4ohm version for me...

http://www.proaudioparts.co.uk/beyma.asp

[DunkH]

Well I modelled the Beyma speaker in WinISD and the plot is awful! I guess you cant have efficiency and a good plot combined together for a small box.

I have modelled the aplha 6 again and it gives a -3db point of 80hz in a 15 lite box which would give a dimension of the ghetto blaster of 18x42x20cm HWD.

I also found some cheap skytronic speakers that look like they would work well and are only £6 each, but they are 8ohm and 90db, but sheap enough to use 2 each side.

I will keep thinking about it..

[Inductor]

Join this one to the lot, Visaton BG 20 8 OHM
http://www.visaton.de/en/chassis_zub...nd/bg20_8.html

[chris661]

http://www.parts-express.com/project...roject=Podzuma

Might be what you're after.

Chris

Just a quick thought - car bass speakers (usually made for smaller boxes...)??

[DunkH]

Hi,
Would these speakers be a reasonable choice if I used 2 a side for 4ohms?

The 6.5" ones, they are only £6 (around 7euro) each!

http://www.skytronic.co.uk/product/index.php?s=902.373

They model well in a closed box of around 5-10l for one driver or 10-20l for two. They are 90db efficient but with 2 I guess this goes up to 93db.

Also if I added a switch to enable the rear pair to be disabled would I still be able to use a simple crossover on each speaker to roll off the treble? I guess it wouldn't matter if one or two speakers are attached but I'm not sure. Also if one pair is disabled and the box is closed would there be some strange effects of having one driver "driving" the other through air pressure, like a passive radiator?

The alternative is to splash out around £30 (35euro) for Eminence Alpha 6 and just have 1 speaker a side, they are available in 4ohm(I think) and are efficient even if one is used. They have a -3db of 80hz in a 15l tuned box. The cost is very high though.

[infinia]

I second Inductors choice with possibly a small helper horn tweeter. The alpha is unremarkable really w/o any bass for reggae. http://www.bmm-electronics.com/Produ...roduct_ID=1919