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description: Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
items: 3 Pi sub questions
items: Re: 3 Pi sub questions

3 Pi sub questions
type: item
description: I have been wanting to build new subs for my home theater. My current subs are in large ported cabinets, and the drivers are not very robust. The 3 Pi sub looks like a nice size, and appears to play deep and loud, with a robust driver. I have a Sony home theater receiver that has a single RCA sub out, and offers built in room correction, by using a microphone to listen to the rooms and make adjustments. Currently, the single RCA sub out goes to a Crown PA amp capable of delivering around 600 watts per channel into 4 ohms with a high dampening factor (over 1000 at 100 Hz if I remember correctly). Is 600 watts enough for 2- 8 ohm Lab12's in parallel? If I added 2- 3 Pi subs flanking the right and left main speakers, and then added 2 more 3 Pi subs in the corners of the room, how would I attach these 4 subs to my equipment? Do the subs have built in cross overs, so they don't need individual active crossovers? Is there a risk of phase cancelation with all those subs placed around the room? Most subs from manufacturers have a phase switch or knob to get the phase right. What is included in the kit? I'm guessing 4- 3 Pi subs in my room (approximately 30' wide x 18' deep) would recreate explosions very nice if implemented correctly. Is anyone here running 4 of these in a home theater? Onebean
creator: OneBean
date: 2020-01-05T05:52:45-00:00

Re: 3 Pi sub questions
type: item
description: The three Pi sub kit is really just a woofer and port material. We also include the connector panel, a "π" logo and a printed copy of the plans. There is no passive crossover included. The crossover, as you've rightly indicated, is specific to the application. Flanking subs use a different crossover than distributed multisubs. And those are different than a traditional single sub application, which I do not recommend, by the way. There are many suitable crossovers and amps you can use. The simplest would be to mount a plate amp to the back of the box. But most plate amps have limited crossover options. You can also use a separate amp with MiniDSP, which would allow you a great deal of flexibility for crossover filters. Flanking subs use a 100Hz second-order Butterworth filter, which is a one-click setting in MiniDSP. Distributed multisubs can usually be run from the LFE channel. More about multisubs and flanking subs at the link below: Multisubs and Flanking Subs
creator: Wayne Parham
date: 2020-01-06T14:59:32-00:00

Re: 3 Pi sub questions
type: item
description: Wayne, thank you for the reply, I'm reading through all the FAQ's. Please send the plans for the 3 Pi subs, and 2 Pi bass reflex speakers.
creator: OneBean
date: 2020-01-07T03:45:43-00:00

Re: 3 Pi sub questions
type: item
description: You've got mail!
creator: Wayne Parham
date: 2020-01-07T15:08:44-00:00

Re: 3 Pi sub questions
type: item
description: Thank you!
creator: OneBean
date: 2020-01-07T17:03:08-00:00

Re: 3 Pi sub questions
type: item
description: Wayne, on the 3 Pi sub enclosure, is there any internal bracing needed?
creator: OneBean
date: 2020-01-08T14:04:32-00:00

Re: 3 Pi sub questions
type: item
description: No bracing needed. Panel resonances are way outside the passband. No need for insulation as damping material either, for a similar reason. The internal standing waves are also far above the passband.
creator: Wayne Parham
date: 2020-01-08T14:55:16-00:00