|Pioneer HPM 100
Pioneer´s HPM Speaker Series
The Pioneer HPM 100 is, similar to the bigger HPM 150 one of the more popular classic vintage speakers. The HPM 100 is the standard variation of its series, with less expensive versions available, such as the HPM 60 or 40. The speaker, despite being produced for only three years from 1976 to 79 is still widely available and frequently in surprisingly good shape.
The speaker is a 4-way bass-reflex system. It uses the same “High Polymer Molecular” supertweeter technology, as all speakers of the HPM series. Frequently, new owners of used HPM series´ speakers will test the supertweeter and come to the conclusion that they are not working, as they don´t seem to produce sounds. However, in most cases they work! If you encounter similar issues or are wondering why you cannot hear your supertweeters, check audiokarma.org or click here . In most cases they work just fine, but the high frequency they do cover can hardly be heard by the human ear.
To cover the midrange it uses a 4 inch cone with a bigger sized magnet. The HPM 100´s woofer is 12 inch carbon fiber cone. Using carbon fiber as a cone material was new at the time and considered a breakthrough in speaker technology. The woofer size of the HPM 100 can cause difficulties as it refers to the actual cone size. Therefore it does not fit into common 12 inch enclosures. Instead the diameter of the woofer is closer to 13 inches.
Reviewing the quality of the HPM 100, it has to be said that it is did not come close to the bigger HPM 150. They are overall decent household speakers, but have weaknesses in producing depths and a smooth soundstage. It is commonly claimed that the speakers have a coherency problem, which caused the drivers to not work smoothly with each other, which could however be attributed to “wrong” gear. An interesting discussion and collection of critiques can be viewed here.
The value for a pair of decent HPM 100 does usually not exceed $700. It is possible to find a pair for about $300 to $600 with a bit of luck. In most cases the price will be around $500, if the cabinets and drivers are in good shape.
Pioneer HPM 100 Price: $400-700
(Depending on overall condition)
Pioneer HPM-100 Service Manual Link to Service Manual at audiokarma.org