Home » Sponsored » Pi Speakers » Pi Theater 4 driver replacement (B&C DE-250 in lieu of stock Eminence)
Pi Theater 4 driver replacement [message #97456] Sun, 25 February 2024 00:37 Go to next message
Groucho is currently offline  Groucho
Messages: 4
Registered: February 2024
Esquire
Hi Wayne,
As you suggested years ago, I would replace PSD2002 drivers with B&C DE-250 compression units. I found a pair of used DE-250-16 (16 Ohm model): can I adapt it with some mods on L-Pads? Thanks in advance!
Re: Pi Theater 4 driver replacement [message #97457 is a reply to message #97456] Sun, 25 February 2024 09:41 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18787
Registered: January 2001
Illuminati (33rd Degree)

You can, sure, but I'm not sure what values to tell you to use. The values for R1/R2 set the attenuation and also set the damping on the tweeter circuit, which has a large effect on the localized region near the crossover frequency. Too much damping and there's not enough output but too little damping and there's a peak at crossover. So you may or may not need to add a resistor in position Rs.

It's easier with 8Ω drivers 'cause the damping is the same as what the tweeter circuit was designed for. I even made a chart of R1/R2 values that maintained the right damping and provided attenuation at various levels in 2dB increments. But this chart can't be depended upon with other driver impedances.
Re: Pi Theater 4 driver replacement [message #97460 is a reply to message #97457] Mon, 26 February 2024 03:46 Go to previous messageGo to next message
Groucho is currently offline  Groucho
Messages: 4
Registered: February 2024
Esquire
Thanks,
Worth a try or better change the dome/coil with the 8 ohm type?
Re: Pi Theater 4 driver replacement [message #97461 is a reply to message #97460] Mon, 26 February 2024 08:42 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18787
Registered: January 2001
Illuminati (33rd Degree)

I would change the dome/coil assembly to an 8Ω part. To match the sensitivity, replace the 16Ω R1 series resistor value with 25Ω. Do this with series/parallel values of 20Ω and 30Ω, because those are regularly available resistor values.
Re: Pi Theater 4 driver replacement [message #97464 is a reply to message #97461] Tue, 27 February 2024 03:33 Go to previous message
Groucho is currently offline  Groucho
Messages: 4
Registered: February 2024
Esquire
Thank you. Will do
Previous Topic: Time to build 2 pi towers?
Next Topic: Michael Parham
Goto Forum:
  


Current Time: Sun Nov 24 05:24:14 CST 2024

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Miller Audio
Miller Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest