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Plans Request [message #66040]

Mon, 07 February 2011 20:23

rvsixer
Messages: 58
Registered: February 2011

Baron

I've been looking for an affordable HT 5.1 project using 8"-10" 2-ways that's also "all-day" easy to listen to for stereo music. Seems like your designs fit the bill perfectly (thanks for your efforts).

This will be for a smaller (~11'x13') room, based on what I have studying here for the last three days I think I want to go with:

2Pi Tower (Left/Right)

2Pi (Center to fit under TV)

1Pi (Surrounds)

3Pi Subwoofers (dual setup)

Can you answer to the following:

1) Just to confirm, its okay to use the standard 2Pi Tower box, only with the speakers/port located on the 13" face? I'm a speaker neophyte, but I've been playing with some baffle diffraction simulators and it seems to add about +/- 1dB response variation over the standard 16" baffle width.

2) It's okay to change the dimensions of the sub somewhat as long as internal volume remains the same? Due to the small room I need to go with the smallest possible footprint (maybe 14"x16", adjusting the box taller as needed)

3) As suggested here I would run the mains as LARGE to smooth response. Same with the center and surrounds, or run those crossed over to the sub at 40/60/80Hz (my AVR allows individual sub crossover settings for every channel)?

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Re: Plans Request [message #66041 is a reply to message #66040]

Mon, 07 February 2011 21:25

Wayne Parham
Messages: 18783
Registered: January 2001

Illuminati (33rd Degree)

I've sent the plans so check your mail.

Answers to your questions:

rvsixer wrote on Mon, 07 February 2011 20:23

1) Just to confirm, its okay to use the standard 2Pi Tower box, only with the speakers/port located on the 13" face? I'm a speaker neophyte, but I've been playing with some baffle diffraction simulators and it seems to add about +/- 1dB response variation over the standard 16" baffle width.

There's no problem with this modification provided the woofer, tweeter and port stay in the same positions on the front and rear baffles.

Quote:

2) It's okay to change the dimensions of the sub somewhat as long as internal volume remains the same? Due to the small room I need to go with the smallest possible footprint (maybe 14"x16", adjusting the box taller as needed)

This is a safe mod too. Subs are pretty safe to modify because there is no risk of standing waves lining up inside. They're too small with respect to wavelength.

Quote:

3) As suggested here I would run the mains as LARGE to smooth response. Same with the center and surrounds, or run those crossed over to the sub at 40/60/80Hz (my AVR allows individual sub crossover settings for every channel)?

That's right, run the system as "large" so the mains are run without high-pass for modal smoothing.

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Re: Plans Request [message #66048 is a reply to message #66041]

Tue, 08 February 2011 09:59

rvsixer
Messages: 58
Registered: February 2011

Baron

Thanks Wayne for the plans!

So I have been diving deeper into the archives, and came across a post suggesting that 3Pi sub(s) might be overkill for use with 2Pi towers, and multisub smoothing was most applicable to DI/CD applications. So more confused now

.

My aim is being able to get smooth bass response down to around 20Hz for HT use (two across seating), and smooth bass response for stereo music (with or without the subs, as the 2Pi towers reach down far enough on their own).

Maybe I should be looking at non-towers all around, high passed to the subs? Non-towers all around, with none high passed to the subs? Towers all around (except for center which is height constrained)? Tower mains with smaller subs?

I realize there is probably not a definitive answer as each application is different, just looking for what you or others here have experienced as generally working best in smaller rooms.

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Re: Plans Request [message #66050 is a reply to message #66048]

Tue, 08 February 2011 12:35

Wayne Parham
Messages: 18783
Registered: January 2001

Illuminati (33rd Degree)

There's no harm in using modal smoothing, no matter what kind of loudspeaker you use. But the best approach, obviously, is to start with mains that provide constant directivity at high frequency. Then when you use the multisub approach to provide a uniform sound field at low frequency, you'll have spectral balance throughout the room, through the entire audio band.

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Re: Plans Request [message #66053 is a reply to message #66050]

Tue, 08 February 2011 16:26

rvsixer
Messages: 58
Registered: February 2011

Baron

Understood. CD is currently not in the budget, but definitely a possible upgrade path in the future.

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Re: Plans Request [message #66054 is a reply to message #66040]

Tue, 08 February 2011 18:58

justphil
Messages: 114
Registered: December 2010

Viscount

That will be my exact set up aside from I will have different subs. I am just on the fence about weather or not to build the towers or the studio 2pi. I personally think the studios have a sexier look when I picture them on stands but my better half likes the towers.

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Re: Plans Request [message #66063 is a reply to message #66054]

Tue, 08 February 2011 21:31

rvsixer
Messages: 58
Registered: February 2011

Baron

justphil,

What subs are you going with? 3Pi's are doable, but would prefer something with less footprint that still goes down to about 20Hz in room.

EDIT: I just searched and found you are using a TT?

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Re: Plans Request [message #66064 is a reply to message #66040]

Wed, 09 February 2011 06:52

justphil
Messages: 114
Registered: December 2010

Viscount

Yes a BFM design table tuba. It is only good to 30hz I am pretty sure.
http://billfitzmaurice.net/
I am also on the fence if I want to build 4 of these so I can smoothe out any room modes I may have.
http://www.avsforum.com/avs-vb/showthread.php?t=1238398
I hope its ok to link other project sites in here. It isn't that I don't think the Pi subs are a good choice but just isn't what I am looking for build wise. I like something more different.

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Re: Plans Request [message #66078 is a reply to message #66064]

Fri, 11 February 2011 00:30

rvsixer
Messages: 58
Registered: February 2011

Baron

I've just ordered 2Pi Tower kits as mains Smile

.

The plan is to get those built and live with them for a while. If they are satisfying (subjective) and have good numbers (measured response etc) in my 2-person HT at the intended listening spots, I will go ahead and build out the HT as outlined above.

If not, I will move these to surround duty after building CD mains (most likely 4Pi's).

Thanks again everyone for your inputs.

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