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1-1/8" Dome On Axis Frequency Response and Impedance Sweep

The low pass filter is a four element filter. L2 and C2 form an electrical 2nd order filter (a filter using 2 components to 
yield an approximate 12dB per octave roll-off) and yields a 2nd order acoustic response. The impedance compensation 
circuit consists of C3 and R1 which effectively flattens the woofer’s inductive rise, yielding a smooth impedance curve.

C3 is actually two capacitors, one a 47uf non-polarized electrolytic, with a .10uF Dayton Audio film/foil capacitor 
wired in parallel. The reason? NP electrolytics are very cost effective, but exhibit high ESR (Equivalent Series Resis-
tance) and also have some inductive components. Using a small value high quality capacitor placed in parallel with 
the electrolytic will also parallel the undesirable resistance and inductance, thus reducing them greatly. This method 
is called bypassing.

The high pass filter is comprised of C1 and L1, and is also a electrical 2nd order yet it yields approximately a 3rd 
order acoustic response. R2 and R3 attenuates the tweeter’s output 6 dB to match the woofer’s level.

The Crossover Network and Description

Here is the BR-1 crossover schematic.

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Summary of Contents for BR-1

Page 1: ...2 WAYREFERENCE MONITOR SYSTEM Model BR 1 ConstructionWorkbook...

Page 2: ...er design Although cost was a factor the design must offer excellent performance In short a Budget Reference system Hence the name Dayton Audio BR 1 Many of you have a strong interest in building inex...

Page 3: ...on Audio 1 1 8 silk dome tweeter is hands down one of the finest tweeters available in it s price range The response exhibits some peakiness and the driver seems to have a wandering Fs but the sound i...

Page 4: ...and the Le was found to be 1 87 millihenries Using an accurate ohm meter the Re was 6 5 ohms Using the above formula R 1 25 x 6 5 R 8 125 ohms so C 00187 66 C 0000283 farads or 28 3 uF Although these...

Page 5: ...ayton Audio film foil capacitor wired in parallel The reason NP electrolytics are very cost effective but exhibit high ESR Equivalent Series Resis tance and also have some inductive components Using a...

Page 6: ...to achieve a flat overall response The BR 1 measures on axis within 2 0dB from 100 Hz 12 KHz Flat frequency response is desirable so that all frequencies are reproduced with the same loudness over the...

Page 7: ...be relatively benign however It s worth discussing the parallel notch filter because it is a handy circuit that is used to control frequency response peaks A parallel notch filter consists of a capac...

Page 8: ...relationship exists when the tweeter is connected with normal polarity Reverse Tweeter Polarity Page 8 So the values for our proposed parallel notch filter is a 9 4uF capacitor 26mH inductor and a 14...

Page 9: ...8 wide 14 1 4 high with a depth of 11 giving it a small footprint suitable for stand mounting It is recommended to place the tweeter at or slightly below ear height of a seated listener The center to...

Page 10: ...is critical to the proper operation of this speaker system In a worst case situation an improperly wired network can damage your receiver or amplifier Please double and triple check all values and wi...

Page 11: ...the insulation on all wires back about 3 8 1 2 6 Using a crimp tool crimp the 205 terminals on the wire leads To ensure a tight connection gently squeeze the push on terminals with a small pair of pli...

Page 12: ...point it is a good idea to label each wire to ensure proper hook up Masking tape and a marker will work fine 3 Cabinet Assembly Instructions A Installing the Crossovers To mount the crossovers we rec...

Page 13: ...stall Acoustic Damping Foam We ve included two 2 sheets of acoustic foam one sheet for each speaker Acoustic damping foam absorbs internal standing waves inside the cabinet and prevents reflections to...

Page 14: ...2 9 5 1 2 2 Install the foam on the back of the cabinet first and trim around the port tube Make sure it does not obstruct the airflow to the port tube as this will alter the tuning of the box 3 Next...

Page 15: ...allow the faceplate to mount flush with the baffle 1 Attach each wire to the appropriate driver terminals while observing proper polarity positive to positive negative to negative The tweeter has a r...

Page 16: ...ce the speakers so they are at least 3 4 ft from side walls if possible Dayton Audio Last Revised 2 10 2015 daytonaudio com tel 937 743 8248 info daytonaudio com 705 Pleasant Valley Dr Springboro OH 4...

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