If I have a 417, with a 414 Open mesh paper dome on it and the back or bottom of the Ceramic frame; magnet also has a the round Vent Hole...If both top and bottom of the pseaker are open, will that adversely effect the sound and low end frequencies?
Can you tell me what the metal insert / Plate is on the late model Ceramic magnet fame 414?
What is it's function, & how does it effect / impact the cone sound?
Why does the 414 have the large Dust / VC cover w/ the mesh screen?
The Ceramic loaded frames have the vent hole in them, which the Alnico's did not.
Jeff
If I have a 417, with a 414 Open mesh paper dome on it and the back or bottom of the Ceramic frame; magnet also has a the round Vent Hole...If both top and bottom of the pseaker are open, will that adversely effect the sound and low end frequencies?
I may be wrong!
Can't comment about the metal plate, but the 414's VC is vented through the DC while the 417's vented out the rear, so if a vented DC is used on a 417, this then creates a semi-aperiodic vent that should affect both its 'tone' and LF performance, so would require a sealed cab of 'x' net Vb that would have to be arrived at empirically for best reflex performance. If used in an open back MI cab, then you'd just have to try it to see if it sounded 'good enough' to you.
Bottom line, it's probably best to plug up the rear vent when using a vented DC.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Thanks!!!
I may be wrong!

Your neighbors called. They like your music.
Truth be told, I don't remember, just responded to what he wrote, so if he's wrong, I'm wrong. Don't recall having any hands on experience with ceramic 414s and the vast majority of my MI experience is with the 421 series, so what he wrote seemed reasonable...........
I'm surprised that any MI driver would be ventless though. I wouldn't think an aluminum DC would be enough.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

Actually I should expand since what I said was only true of Alnico, but AFAIK all 417 are Alnico.
The late 414 was ceramic, and had a metal plate inside to block the rear vent. That way it could use the standard 414 kit. Must be what he is referring to.
http://www.lansingheritage.org/image...-mi/page04.jpg
Don't think the 418 had a rear vent either. Was also Alnico/aluminum dome
Your neighbors called. They like your music.
I used to be known as "AltecFan" but now I'm "Altec19" . . .
414 open dome, on a 417 kit, in a 12'' vented frame.
Thanks OG.
Some later 12"Creamics had vent Holes in the bottom;
maybe not older ones.
I have two sets, that are not white framed, 1987ish.
917 frames that came with 414's.
I have mentioned this many times without any confirmation, that the later, dark Gray framed Ferrite frames were used for the remaining available 12' spaeker made.
http://www.lansingheritage.org/image...hort/page4.jpg
I may be wrong!
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