Dayton Audio BR-1 crossover network upgrade

Dayton Audio BR-1 crossover network upgrade



Project Category:
 Bookshelf Speakers

Project Level:

Project Time:

1-8 Hours

Project Cost:

Under $100


Project Description:

The Dayton Audio BR-1 is a 6.5″ 2-Way Bookshelf Monitor Speaker. This is an upgrade to its crossover networks. This modification employs the DC-biasing of crossover capacitors to improve sound. It applies a DC offset to each of the capacitors in the network to reduce circuit distortion. A 9-volt battery supplies the voltage.

Design Goals:
The objective of this project is to improve the sound of the BR-1 speakers by improving the linearity of the crossover networks through biasing of the crossover capacitors. The total parts cost is to be less than $40 for the speaker pair.

Driver Selection:

The drivers are those included in the original BR-1 design
Two Dayton Audio DC160-8 6-1/2″ classic woofers
Two Dayton Audio DC28F-8 1-1/8″ silk dome tweeters

Enclosure Design:

The speaker cabinets are the original Dayton Audio 6.5″ 2-Way BR-1CAB.

Crossover Design:

The DC voltage shifts the signal away from zero, so the waveform does not cross the zero point. This linearizes the waveform of the passive components thus reducing the distortion and improving the sound. The audible effects are increased spatiality, detail, and purity.
Because the battery simply supplies a bias through a high value resistor there is no appreciable current consumption. Battery life is the same as with natural discharge or years. The expiration date of the battery coincides with the need to replace it. Each capacitor in the network is in fact made up of two capacitors of equal value connected in series. Although the battery voltage applied to the center connection of the two capacitors biases them both, no DC voltage appears at the output. The result is sound with increase in detail, smoothness, and resolution. A dead battery has no other effect on the network circuitry, and consequently no other symptoms.
It is easy to make biased networks. Here is how to modify the BR-1 crossover network. The original C1 cap was 6.2uf. To set one up biased for the same value, wire two 12uF caps in series. Then place a 2.2 meg resistor between the caps and tie the + side of a 9Volt battery to the other side of the resistor. The negative on the battery goes to ground. The original C2 cap was 3.0uf. Wire two 6.2uF caps in series. Then place a 2.2 meg resistor between the caps and tie the same 9Volt battery (+ side) to the other side of the resistor.

Tips & Tricks:

All capacitor types improve. You could also upgrade to the Solen brand, also available from Parts Express.
The $40 cost to implement is because it requires higher capacitance capacitors and double the parts.

I am pleased with the results of biasing. Some may describe the effect as subtle. However, the BR-1 is considered by many to be one of the finest sounding speakers and deserving of this improvement. I think you will not be disappointed and find that the design goals were accomplished.

About the Designer:
 I am a high-end audio fanatic. I have been building speakers since I was 10. DC-biasing of crossover capacitors is something that has existed for many years. This trick to help improve the sound of passive components goes back to the early 90’s and before when this technique for speaker systems was used.

Project Parts List:

027-427Dayton Audio DMPC-6.2uF 250V Polypropylene Capacitor2
Capacitors 6.2uF salvaged from original network2
027-430Dayton Audio DMPC-12uF 250V Polypropylene Capacitor4
142-231PKCELL 9V Ultra Alkaline Battery2
090-8059V Battery Clip Connector2
Resistor 2.2 meg ohm 0.25-Watt4


Add yours
  1. 3

    I could not recommend a preassembled passive crossover for the Cerwin-Vega SL-12, but P.E. does carry quality passive crossover components.
    Critical crossover design considerations:
    • Driver impedance.
    • Power rating.
    • Crossover points for driver complement.
    • Audio grade capacitors for mid-range and tweeter signal paths.
    • Wire gauge of inductors used for low DC resistance.
    To upgrade the current system, I recommend inspecting it for audio grade capacitors in the mid-range and tweeter signal paths. If Cerwin-Vega used electrolytic s, replace them. Otherwise, I would leave it alone or improve linearity by employing this modification of DC-biasing.

  2. 4
    terry duty

    Thankyou very much for this Ihave been looking for something to take the br-1 tithe next level cheaply. I’m a buget audiophile. I really do appreciate your help and expertise

+ Leave a Comment