Tuesday, November 29, 2016

AC130F1 and Fountek horn loaded ribbon bookshelf

This little bookshelf started by looking at excellent fr response of Aurum Cantus 5" midbass AC130F1. Originally I wanted to pair it with small Dayton dome tweeter, but sound was lacking something. Fountek true ribbon in its horn loaded offering has excellent spec and sounds great. These two are meant to work together. I used rather simple crossover, first order series crossover, with just one cap and one inductor, at 7kHz. I selected this crossover frequency to suppress small breakup bump on midbass. Plus ribbons like to be crossed high. I added baffle step later, to compensate for rising response. Just one inductor in parallel with resistor.
Below are some pics from setup with mini dsp crossed at ~150 Hz to subwoofer. You can see how well the little speaker measures, almost ruler flat, this is in room response. First response is just the bookshelf alone, second one is with the sub. Off axis behaviour is exceptional.









Thursday, November 17, 2016

FM radio stations near Washington DC

Frequency                 Name                         Comment

88.1                           ?                                 latino
88.5                          WAMU
89.3                           ?                                 jazz
90.1                           WCSP                        mono, politics...
90.9                           WETA                       classical music, great
91.3                            ?
91.5                            ?                                classical from Baltimore
91.9                            ?                                christian
92.3                            ?                                crap
92.5                            WINC FM               
93.1                            ?                                country
93.3                            ?                                country
93.9                            ?                                crap
94.3                            ?
94.7                            ?                                rock
95.5                            WPGC                      crap
96.3                            WHUR
96.7                            ?
97.1                            WASH
97.5                            ?
97.9                            ?
98.3                            ?
98.7                            WMZQ                     country
99.1                            Bloomberg
99.3                            ?
99.5                            HOT99.5
99.9                            WFRE Frederick      country
100.3                          BIG100.3                  rock
101.1                          DC101                      idiot in the morning
101.5                          ?
102.3                          ?
102.7                          ?
103.5                          WTOP
103.9                          ?
104.1                          ?
104.7                          ?                               country
105.1                          ?                               christian
105.9                          WMAL
106.7                          The FAN106.7
107.3                          ?                               rock
107.7                          ?
107.9                          ?                               latino