Recommend me a speaker??

[jallen97]

I am a roving elementary music teacher and I like to play tracks that sound good. I also need something fairly loud as part of the time I am playing tracks with about band of around 20 flutes, clarinets and trumpets.
I've been using a bookshelf speaker(zip-tied to a cart I pull around)with a little class d amp. It's a speaker I always liked the sound of but its not quite loud enough.
I've built a couple BFM speaker designs and am thinking about building something to fit the bill for my teaching job. As I have to lug it around all day, weight and size is an issue. I've been a bit intrigued by the full range designs I've been seeing on this forum. I'm not very familiar with them though. Also, the FAST designs look interesting but I'm wondering if that would be a bit too much weight.

 

[picowallspeaker]

Hi, probably you need something like a 12" plus a 1" CD in a horn ( compression driver = CD ) in a ABS box. That's what the basic DJ rig requires.
Something like the classic Electrovoice monitor...
(You can search for some Econowave thread in many forums if you want to DIY such thing )
The active version has the amplifier built into the cabinet, and it's heavier !

You'd want to use professional drivers as they are in the mid-to-high efficiency range so for the same wattage they'll produce more SPL.
A single cone ( the one with the whizzer cone in it ) would not deliver full efficiency in the treble range even with heavy equalization.

 

[Jim Shearer]

As a former volunteer sound tech for a children's theater company, I second pico's recommendation. I used Electro Voice SX300 speakers, which I think would be adequate for your application. But they are heavy!

So... maybe have a look at XRK971's mini-Karlsonator thread. Think about building something like a Karlsonator w/ a 12" driver (perhaps Eminence Beta 12 LTA?), but using 1" thick XPS insulation board with a 1/4" plywood cladding to give it some durability. Perhaps a 50 watt chip amp could be enough to power it?

Cheers, Jim

 

[jallen97]

Thanks for those recommendations! I am really trying to go small and light since I have to heave it in and out of my vehicle 3 times a day.
Those Karlsonators are very interesting. I think I'm gonna keep reading up on them. Might make a small one and see how loud it is. And if isn't loud enough I'll find another use for it and go bigger.


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[jallen97]

Thanks for those recommendations! I'm really trying to go as light/small as I can as I have to heave it in and out of my car 3 times a day.
Those Karlsonators are very interesting! Gonna keep reading up on those and maybe try a small one and see how loud it is. If I need to go bigger I'm sure I'll find something to do with the little one. [emoji1]

 

[picowallspeaker]

Hi, I wouldn't recommend any semi-soft material, indeed it should be strong and for our purpose it must be soundproof.
But in real world applications, I know, you can make accomodations...
( BTW what kind of source are you using ? Compressed files on a tablet ? )
Ideally, you should make something like this
http://www.diyaudio.com/forums/everything-else/291073-elan-console-kickstarter.html
or maybe participate on raising funds and get it !!!
A special version with handle or strap...

 

[perceval]

I think X's karlsonators would do a great job, couple that with a little 7492 D amp and yes, you could use a phone or tablet with EQ to adjust a little.

Would make for a cheap but powerful little project.

 

[xrk971]

Thanks for recommendations guys... I totally agree.

The mini Karlsonator with dual Dayton PA130-8 drivers would get 96dB at 2.83v sensitivity and get bass down to 55Hz and probably be the perfect solution. If made of foam core they would be very light. Thinner plywood would of course sound great but a bit heavier.

The biggest advantage that the Karlsonator design has is that it has so much bass gain, it needs no baffle step compensation. When placed on the ground in 2pi space, the bass SPL matches the rated SPL down to the F3 point of about 60Hz. The K-aperture provides a very wide and uniform sound field so it sounds a lot bigger than it is. Of all the speakers I have built, I come back to this GregB design time and time again as one of my favorites for wide sound field, ease of listening, crisp dynamics, and rich full bass.

If 90dB sensitivity is enough, a single PA130-8 also works quite nicely. I find that the single is quite a capable speaker as the driver is a pro-audio grade unit with treated cloth surround and a substantial magnet.

The 0.53x scale size is just about perfect for portability.

http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-133.html#post4275855

Here is 0.53 Karlosnator with a single driver:

http://www.diyaudio.com/forums/full-range/268524-xki-xs-ab-initio-karlson-6th-order-bandpass-55.html

Alternatively, the dual PA130-8 XKi could also work and be more compact.

Here is an XKi with two PA130-8 drivers:
[IMGDEAD]http://i63.tinypic.com/2qdo4tk.jpg[/IMGDEAD]

 

[jallen97]

Can't wait to try one of these out!!!
Looks like there is not too much difference between the .40 and .53 size wise? An inch or 2 on each side?
So the foam really works??
I may stick to plywood for durability or maybe foam just inside.
I'm assuming you glue them together? When I've built BFM boxes I used PL construction adhesive. Do you use something similar?


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[xrk971]

There is a big difference in size between 0.53x and 0.40x as full scale is 30in tall.

Foam core works well - use hot melt glue to make assembly go fast as glue dries in seconds. You can build most of it with hot melt and final piece is the side and that has to be glued with slower drying glue like PVA, Titebond, non VOC liquid nails, PL premium etc, gorilla glue works but is a mess and expensive.

Read Foam Core thread to get construction techniques. In 0.53x K'nator thread there is section on the "score and fold" method whereby a long piece is scored and folded so you have minimal glue joints.

 

[jallen97]

Oh yeah... I guess it's more like 4 inches(I should've done the math)
I'll read up on the foam. Thanks!!!

 

[jallen97]

Anybody know where I might find some dimensions for a .53x Karlsonator with dual PA130-8s? The plans I find don't have enough room to mount the 2 drivers. It seems like I read somewhere about a general guide for figuring out the dimensions for those internal parts but I can't find it now. I just want to make sure I get it right the first time. [emoji1]