Vintage article - "A No Cost Acoustic Cabinet for Transistor Portables"

[freddi]

(I remember those days clearly of pocket radios)

 

[Galu]

These days, you can do similar with your smartphone!

Amplify Your Smartphone Speakers with Household Items (Infographics)

 

[jjasniew]

Ya, but those arent quite as cool as the - obviously - mini Karlson-izator shown in the transistor portable article!

TLR - I wonder if Karlson is credited in the article?

 

[chris661]

Well, how about a Karlson with a smartphone slot?
With 3D printing, we could probably do something really cool.

Chris

 

[EddieT]

I remember the article. I didn't have a small radio so I didn't try it but at a glance it looked like the radio slot slanted the wrong way.

 

[xrk971]

I should 3D print a mini Karlsonator for a 2.5in full range driver. Or just a K15 scaled to 0.17x for fun. That's about a 5in tall box - still a sizeable 3D print that will take 8hrs.
But it will be very cool - especially in metallic gold filament.

 

[freddi]

here's Partsexpress listing for 2.5" drivers

Midrange/Midbass Drivers & Full-Range Speakers - Parts Express

Lavoce has 2" and 3" but not a 2.5" - here's a 3 with lots of on axis rise

the Lavoce I bought was well made with meaty/sturdy terminals

https://www.parts-express.com/pedocs/specs/293-705--lavoce-fsf030.70-specifications.pdf

 

[EddieT]

Here's another vintage article, see page 81.

https://worldradiohistory.com/Archive-Poptronics/50s/57/Pop-1957-10.pdf

 

[freddi]

yes - probably the smallest "K15" ever featured. One thing to note is the narrow slot at the top of the aperture and its effect on sound.

Its like that with my 41.5" tall K18 - this is a real good cabinet with curved refector. To to it again, I'd like to get it about 36"J x 21"W x16" deep.

At higher input power, a breeze can be felt from the narrow - top slit area. Its not destructive and does not compress as the inner vent area is adequate. If that portion is blocked, then the coupler somehow seems to have less agility and life - dunno why as its run 18 inch speakers. Then again, EV18B goes to 4KHz on axis. Its run two different spec Eminence 18s besides the EV - all good and better than the same drivers as direct radiator.

 

[EddieT]

Freddi, was that your little acrylic (or plexiglass) scaled K12 you posted on the the HESA forum?

 

[freddi]

sure not mine - that plexi K is based on the "Dutch K12" and probably would be fun as K8 or even K6 size when augmented with a woofer/subwoofer.

got any wood to make a K6? - I don't think there are any low priced 6 inch fullrange speakers (?). that's a shame as Visaton's BG20 motor would make a nice "6".