The PHILCO Phorum

Full Version: 1937-38 Acoustic Clarifiers
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Are the clarifiers used in the 1937-116 & 690 the same as the ones in the 1938-116 & 690?? can they be swapped ?
Thanks,

Gene
Yes. Same size, same appearance, made the same as far as I can tell.
Thank You, Ron!!

Gene
I know that if I were running Philco I would have used the same design of clarifier from 1936-38, there wouldn't be any point in changing them without a valid reason.
Regards
Arran
I fail to see the reason of making tens of new models every year and discontinuing the previous ones....they did it all the time.
They did that to some degree but mostly they just facelifted existing models and made some technical mods. The Philco 60 and 89 were examples of this, the changes were mostly on the cosmetic side such as cabinets.
Regards
Arran
On the subject of Acoustic Clarifiers... how the H**l do they work? I've actually spent some time examining the patent, but to me they seem to be passive radiators in a a non sealed (that's an understatement!) box, which seems absurd.
They are passive resonators, that help dampen out cabinet sympathetic vibrations.

Ron can correct me if I'm wrong, but many of those high-end cabinet did have backs.

Chuck
OK Chuck

The 1936 and 1937 Philco models with clarifiers (116X, 116PX, 680X, 37-116X, 37-690X) did not have backs. Philco used ventilated backs on the 1938 models (38-690, 38-116 plus several lower end consoles without the High Fidelity circuitry and with no clarifiers). Even in the 1938 models, the woofer chamber was not sealed.
You do not necessarily have to have back for it to work. Often times the radio was against the wall, so the wall and the narrow space between the radio served as the lossy load, so clarifiers could use that. But even without back the very presense of an anti-resonator tuned to the resonant frequency of the cabinet/speaker system helps somewhat.
Interesting. Has anyone actually done an A/B test to see if they're actually doing anything?
When I have my 38-116 Playing, It sounds better if it is put up against a wall. The bass is much more present. Do not know if the clarifiers do anything. I think it was a gimick Philco came up with to compete with RCA as RCA used the sound tubes in their sets.. Just my thinking.........what do you guys say?
My feeling is that they do work. The Philco patent filed for the clarifiers shows a bass response curve of the cabinet with and without the clarifiers. Without them there is a pronounced peak at the cabinet resonant frequency, while with them the peak is reduced by about 10 dB.

The clarifiers are actually tuned damping diaphragms, which absorb and dissipate energy at their self resonant frequencies.

Here is a link to the actual patent:

https://patentimages.storage.googleapis....059929.pdf
Ah, yes. The "bass reflex effect" with a console up against the wall.

Forgot about that. D'oh!

I'm properly chastised....

Chuck Icon_smile