10-03-2015, 02:14 AM
I did some experimenting tonight and here is some more results.
Just to give specs the speaker is mounted via 3 bolts to the baffle board. That board has the cloth glued to the front edges and lays over the speaker opening. The baffle and speaker are then mounted into the cabinet itself via 3 bolts as well.
-With everything mounted as it should be I get the buzz-vibration about half volume and up depending on strength of the station and volume
-With the speaker removed from cabinet and the baffle there is NO BUZZ at all, It sounds GREAT.
-With the speaker mounted on the baffle board (with the new speaker cloth) but removed from the cabinet I get the BUZZ and it is basically the same as with everything mounted in the cabinet.
-This tells me there is NOT an obvious issue with the speaker or the cabinet themselves. It is when the speaker is mounted to that baffle with the new grill cloth that there is an issue.
-I took a piece of white paper and laid it over my speaker loose from the mount and cabinet and I could replicate the sound almost identical to the speaker in the baffle with the cloth.. I did notice if I laid the paper and completely sealed the speaker off it would NOT buzz at all. Only when the paper was covering the speaker with a small amount of air allowed to move in and out did the paper BUZZZZ like crazy. Thus I am thinking this speaker cloth restricting air movement but allowing just enough to cause a resonance in the cloth and maybe even the speaker cone itself. When something hits a resonant frequency everything starts to vibrate and buzz.
My only other alternative right now is to remove the new grill cloth and replace it with something else or better yet build a new baffle and experiment with with various other materials and see what happens.
I think the new material is restrictive enough to cause this issue with my particular speaker and board. It might not happen with another Philco 80. Mine is very loud and powerful....definitely not a wimpy little radio, she really cranks out. I also found I have no need for the "gimmick" or any other tricks this 80 it is plenty powerful and grabs tons of stations out of the air. I really wish I could get this old girl working as should...she sure is pretty and sounds wonderful for such a small thing.
T
Just to give specs the speaker is mounted via 3 bolts to the baffle board. That board has the cloth glued to the front edges and lays over the speaker opening. The baffle and speaker are then mounted into the cabinet itself via 3 bolts as well.
-With everything mounted as it should be I get the buzz-vibration about half volume and up depending on strength of the station and volume
-With the speaker removed from cabinet and the baffle there is NO BUZZ at all, It sounds GREAT.
-With the speaker mounted on the baffle board (with the new speaker cloth) but removed from the cabinet I get the BUZZ and it is basically the same as with everything mounted in the cabinet.
-This tells me there is NOT an obvious issue with the speaker or the cabinet themselves. It is when the speaker is mounted to that baffle with the new grill cloth that there is an issue.
-I took a piece of white paper and laid it over my speaker loose from the mount and cabinet and I could replicate the sound almost identical to the speaker in the baffle with the cloth.. I did notice if I laid the paper and completely sealed the speaker off it would NOT buzz at all. Only when the paper was covering the speaker with a small amount of air allowed to move in and out did the paper BUZZZZ like crazy. Thus I am thinking this speaker cloth restricting air movement but allowing just enough to cause a resonance in the cloth and maybe even the speaker cone itself. When something hits a resonant frequency everything starts to vibrate and buzz.
My only other alternative right now is to remove the new grill cloth and replace it with something else or better yet build a new baffle and experiment with with various other materials and see what happens.
I think the new material is restrictive enough to cause this issue with my particular speaker and board. It might not happen with another Philco 80. Mine is very loud and powerful....definitely not a wimpy little radio, she really cranks out. I also found I have no need for the "gimmick" or any other tricks this 80 it is plenty powerful and grabs tons of stations out of the air. I really wish I could get this old girl working as should...she sure is pretty and sounds wonderful for such a small thing.
T
