Cheap & easy cylindrical column loudspeaker

[gpapag]

Hi all

This is a “custom design” speaker “enclosure” for my 18 y.o. daughter.
It is a means to convince her that it is worthy having a more descent sound in her student apartment than the one she has now (she is happy to use the ASUS PG191 PC monitor speakers+Sub as the sole reproducer of sound for listening to .mp3 music files, web radio, video DVDs and TV through the soundcard).
She lives in a city away from where I’m living, so I had to build the speakers in her own apartment.
Therefore, ease of implementation and maintaining a clean “construction site” was a pivotal factor for to gain her permission to build it. In addition to this, the speaker had to be floorstanding with small footprint, lightweight and “aesthetically acceptable”. My contribution to the specification list was that it had to be built with pocket money and in a way that it would accept a better motor some months latter without major modifications.
Finally, it had to be constructed as a disposable - or at least as a recyclable - item in case that she wouldn’t like it.

Packaging paper (roll carton) is the material to fulfill all the above requirements, plus some.

The carton allows for a multicell guide that minimizes internal reflections along with some mild HF attenuation down the cylinder axis, resulting in very clear midfrequency reproduction even with the currently installed crappy motor.
(a cheap 5 Euro coaxial 3.25 inches car speaker with an fc ~200Hz).

Not much of bass frequencies, but quite a balanced –bandwidth restricted-sound. The target of clear mids is achieved.
Any suggestions for 100-150Euro/pair, 4-6 inches full range motor is welcome.

The speaker lends itself to artistic trimming by drawing or painting directly over it’s outer surface. It can also be easily dressed-up and undressed with color paper or fabric.

[gpapag]

The addition of a reflector provides a degree to directional control over the speaker’s output, increasing the dialogue intelligibility when watching TV from the far side of the -now naked and acoustically live- room.
For listening to classic music I prefer not to use this reflector, but for modern pop music it’s use is acceptable.
Reducing reflector’s size and/or adding some hard and more reflective surface (kitchen aluminum foil laid over part of reflector’s surface) is something that I can try these days.

[gpapag]

The speakers are driven by an LM3886 chip amplifier that I built 6 years ago

(I am still trying to persuade my daughter to accept having two more boxes on her desk. The shape and colour of the PSU/Amp combo may influence her decision).

Regards
George

[mctavish]

Now this is the true DIY SPIRIT! Cant let good people go through life with crappy computer speakers now can we? Cheers to you sir, looks like a very interesting design. Seems like this would be great for a medium Q full-range driver with a nice off-axis response? Some of those Vifa or Tang-band drivers maybe....

[gpapag]

mctavish
Thank you for your kind words.
Yes, crapy PC speakers make me nervous. But young people are used to them.
Anyway. This construction is easy to implement.
It will take ~2 months till I go home where I could build it again and take some measurements.
I would be glad if you or anyone else build such a construction using a motor you are familiar with it's sound and report back.


Regards
george

[kristleifur]

Wow, very cool

[kristleifur]

Approximately how would the dimensions be with this 3" driver? (If it's suitable at all!)

BB 3.01 - Omnes Audio 3 inch full range driver - Europe Audio

[norman bates]

nice !!!!!!!!!!

I've noticed how many Japanese designs are up-firing, small to large full range drivers.

Norman

[gpapag]

Dear kristleifur
For fc=95Hz of this motor you link to, the tube hight should be 0.9m (1/4 wavelength)*. You can use the drawing I used and subtract 10cm from the hight of each roll.
I would not reduce the diameter of the tube.
It takes about 30m of roll carton to build two "enclosures". Here it costs 0.4Euro/meter=12 Euro total.
But you can start by building just one enclosure (6 euros), listen to it and then decide if it worts spending another 6 euros.
Regards
George

*PS:Provided it works as a MLQW. I am not sure if this is so. An impedance plot should clear this out.

[gpapag]

Norman
I am located far away from Japan, but these speakers

Full Range Speaker Photo Gallery

still sound good to my ears.
(It takes some OB to match (?) them.

Regards
George