Home » Sponsored » Pi Speakers » four Pi and subs
four Pi and subs [message #93769] Sat, 15 May 2021 10:13 Go to next message
Jetpump is currently offline  Jetpump
Messages: 6
Registered: July 2020
Esquire
I'm still lurking about with the 4pi idea. Why does the sub need to sound good up to 200hz? How well will SVS SB-3000 subs do?

Thanks,
Billy
Re: four Pi and subs [message #93770 is a reply to message #93769] Sat, 15 May 2021 10:16 Go to previous messageGo to next message
Jetpump is currently offline  Jetpump
Messages: 6
Registered: July 2020
Esquire

Wayne Parham wrote on Tue, 19 May 2020 15:59
The woofer and tweeter are direct replacements, and they can be exchanged through the front of the baffle. The cabinet stays the same.

There are some crossover changes required, but they are inexpensive and pretty easy to do. Some resistor values are different for the DE250 because it has slightly higher voltage sensitivity than the PSD2002. You can see the components used for each option in the "Notes" section of the crossover document.

Here are some of my thoughts about the upgrades available:

For different compression drivers, is it only resistor swaps? I guess I'm wondering if the horn dictates the frequency response vs. the driver for crossover design.

Thanks,
Billy
Re: four Pi and subs [message #93776 is a reply to message #93770] Sun, 16 May 2021 09:16 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18148
Registered: January 2001
Illuminati (33rd Degree)

Compression driver changes sometimes need different R1/R2 values to match voltage sensitivity. The amplitude and polar response is set by the waveguide, which is has much more influence than the driver.

The only things set by the driver are mass-rolloff - which sets the upper frequency limit - and breakup modes which must be well damped or they end up being deal-breakers. So basically, compression drivers act similarly provided they have adequate high-frequency response and don't have excessive breakup in the top octave.

As for subs, the reason we need clean output above 100Hz is for a specific application called flanking subs. That configuration blends the subs with the mains up to around 150Hz or so. It is done to smooth higher frequency room modes and SBIR from nearest boundaries. It is a type of multisub configuration, part of a complete multisub setup.

You might do some searches and read on the concepts of flanking subs and multisubs to learn more about their benefits.
Previous Topic: Horn loaded Corona Build
Next Topic: Amp Camp Amp
Goto Forum:
  


Current Time: Sun Oct 17 14:17:19 CDT 2021

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Smith & Larson Audio
Smith & Larson Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest