Need help to ID these speakers - Altec?
- Thread starter Wardsweb
- Start date
Don McR
Well-Known Member
The part numbers for the 870B are shown here:
http://www.lansingheritage.org/images/altec/reference/1975-drivers/page06.jpg
The system you refer to seems to have been modified after the fact. They've added the 3000H tweeter that was not part of the original system. The original system consisted of the 420-Y driver only. That driver is actually a three-way system. The strange looking cone contains a compliance midway up the diaphragm that acts as a mechanical cross-over. The center portion of the cone decouples from the main diaphragm at higher frequencies so that only the center six inches reproduces the midrange frequencies. The whole 15" diameter cone moves as one at low frequencies. High frequencies are handled by the small tweeter mounted coaxially on the bar across the face of the driver using an electrical cross-over.
These drivers were known as "bi-flexs", with the best known system being the later 879 Santana. They do not have a very good reputation. They are coloured sounding compared to the 15"/horn systems like the Valencia. They also don't have the same bass impact or extension.
You should also note that no one offers replacement cones for the "bi-flex" - not even Bill Hanuschak. If you blow it, it cannot be repaired. As a silver lining the chasis is the same as the 416-8A and it can be made into that driver with a recone.
http://www.lansingheritage.org/images/altec/reference/1975-drivers/page06.jpg
The system you refer to seems to have been modified after the fact. They've added the 3000H tweeter that was not part of the original system. The original system consisted of the 420-Y driver only. That driver is actually a three-way system. The strange looking cone contains a compliance midway up the diaphragm that acts as a mechanical cross-over. The center portion of the cone decouples from the main diaphragm at higher frequencies so that only the center six inches reproduces the midrange frequencies. The whole 15" diameter cone moves as one at low frequencies. High frequencies are handled by the small tweeter mounted coaxially on the bar across the face of the driver using an electrical cross-over.
These drivers were known as "bi-flexs", with the best known system being the later 879 Santana. They do not have a very good reputation. They are coloured sounding compared to the 15"/horn systems like the Valencia. They also don't have the same bass impact or extension.
You should also note that no one offers replacement cones for the "bi-flex" - not even Bill Hanuschak. If you blow it, it cannot be repaired. As a silver lining the chasis is the same as the 416-8A and it can be made into that driver with a recone.
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