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Anyone build Wayne Parham's Pi-4 speakers? Impressions? - Page 6

post #151 of 170
9/6/10 at 2:21pm
Easy button max fits those dimensions
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post #152 of 170
9/6/10 at 2:50pm
Thread Starter 
I've looked at NeoDans thread and I know there are variations, which version are you thinking of for the space and what orientation?
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post #153 of 170
9/6/10 at 3:57pm
I believe dan run his horizontal and pointed at the side wall instead of the listener. You could build two and crumble that nice theater you just built

Actually looking at that space again you could do the vertically standing easy buttons and fit them between your speakers
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post #154 of 170
9/6/10 at 6:11pm
the behind the screen picture concerns me a little bit. it seems that you have several boundaries ~4 feet from the speakers. 1/4 wavelength to a boundary creates a cancellation. it seems that you may be knocking out a lot of the bass performance in the 60-80 region (4 feet to a boundary puts a cancellation at 70hz), which is in the wheelhouse for 4 pi's.
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post #155 of 170
9/6/10 at 7:01pm
Thread Starter 
If you have any test gear I think it would make a nice road trip for you to come up for a visit and help me see how my room measures.
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post #156 of 170
9/7/10 at 6:01am
Quote:
Originally Posted by LTD02 View Post

the behind the screen picture concerns me a little bit. it seems that you have several boundaries ~4 feet from the speakers. 1/4 wavelength to a boundary creates a cancellation. it seems that you may be knocking out a lot of the bass performance in the 60-80 region (4 feet to a boundary puts a cancellation at 70hz), which is in the wheelhouse for 4 pi's.

He should have very thick treatments (maybe with membranes) behind the speakers to handle that issue. That along with the XO between the mains and the sub will handle it just fine.

Its a null anyways and outside of wanting perfect measurements there isnt much about a null that hurts the bass.
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post #157 of 170
9/7/10 at 6:12am
Thread Starter 
I have two inches of linacoustic on the front wall, The side columns are faced with 1 inch under the fabric, The side walls have 1 inch.
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post #158 of 170
9/7/10 at 6:29pm
Quote:
Originally Posted by BIGmouthinDC View Post

Thanks Nick, just a random observation. A couple months ago when we compared my old speakers to your initially assembled pair of 4PIs we noticed a substantial difference in the treble range. I was pleasantly surprised to discover that I am not experiencing nearly the same magnitude of difference in my final speakers. I don't know what to attribute that to, your amp, different room acoustics, or the difference in the crossovers which we discussed.

You need to come over for a listen.

Hmm, interesting. I wonder what it could be. I have to get mine up and running again with the proper capacitor and then may bring one of them over for a direct comparison. It is going to be a month or so before I get them together. Maybe by then you will have built your new subs.
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post #159 of 170
9/11/10 at 6:10am
Did you try out varying degrees of toe-in? I'm curious if you ended up with the speakers firing directly forward or if some toe-in ended up with better imaging for music/movies.

Your screen size and room width are almost identical to mine, and I'm finalizing my cabinet design for an e-wave build, which should have comparable directivity to your 4pi build.

Best,
C.
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post #160 of 170
9/11/10 at 8:12am
This is a link that LTD02 put up about a page back in this thread that has some good info for you.

http://www.audioroundtable.com/PiSpe...ges/23369.html

I did this with my Ewaves and noticed a big change in 2 channel but not as much for multi channel.


Quote:
Originally Posted by Cerdic View Post

Did you try out varying degrees of toe-in? I'm curious if you ended up with the speakers firing directly forward or if some toe-in ended up with better imaging for music/movies.

Your screen size and room width are almost identical to mine, and I'm finalizing my cabinet design for an e-wave build, which should have comparable directivity to your 4pi build.

Best,
C.
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post #161 of 170
9/11/10 at 9:40am
Thread Starter 
Quote:
Originally Posted by Cerdic View Post

Did you try out varying degrees of toe-in?

Toe-in is problematic in my space unless I take a saw to the wall. The room is shorter behind the left speaker.

Another reason is that the AT of the screen deceases with the angle of the sound.
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post #162 of 170
9/11/10 at 11:36am
How high up are your ears in relation to the center of the horns or 15's?

What is that empty cavity under the center channel? Can you cover it up so it's not a cavity anymore?
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post #163 of 170
9/11/10 at 11:56am
Quote:
Originally Posted by BIGmouthinDC View Post

Toe-in is problematic in my space unless I take a saw to the wall. The room is shorter behind the left speaker.

Another reason is that the AT of the screen deceases with the angle of the sound.

Pity as all the controlled directivity designs I've used have universally sounded better toed in heavily with the horn/WG axis crossing in front of the listener.
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post #164 of 170
9/11/10 at 12:18pm
Thread Starter 
Quote:
Originally Posted by CZ Eddie View Post

How high up are your ears in relation to the center of the horns or 15's?

What is that empty cavity under the center channel? Can you cover it up so it's not a cavity anymore?

Depends on where you are sitting. I have 3 rows of seating and the mid point of woofer/horn is a few inches above the listeners ear in the middle row. I plan to bring them down a tad in my final set-up.

That empty cavity is just a 3 sided MDF box that I am using to elevate the middle channel temporarily until I build in my subs and maybe do a THX baffle wall. I have it totally stuffed with leftover bits and pieces of acoustical treatments.
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post #165 of 170
9/11/10 at 12:19pm
Thread Starter 
Quote:
Originally Posted by A9X-308 View Post

Pity as all the controlled directivity designs I've used have universally sounded better toed in heavily with the horn/WG axis crossing in front of the listener.

Understood. Is your experience two channel or 7 channel listening?
Behind a woven screen?
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post #166 of 170
9/11/10 at 12:24pm
Quote:
Originally Posted by BIGmouthinDC View Post

Toe-in is problematic in my space unless I take a saw to the wall. The room is shorter behind the left speaker.

Another reason is that the AT of the screen deceases with the angle of the sound.

Chris Seymour in the Seymour AV thread also thought that to be the case, due to experiences with earlier AT materials, but changed his mind after doing some measurements (I believe this was pre-Center Stage material; YMMV for SMX I guess):

http://www.avsforum.com/avs-vb/showt...2#post12824882

Quote:


Well, the data is in and it shows me not only how some of my experiences derive from, but also where I'm wrong. My basis for recommending that folks try to minimize their speaker angles with respect to the screen (e.g. fire them straight through - don't tow them in) came from previous experience with acoustically transparent large and small-format screens and their tendency to affect the sound at different speaker angles. My analogy with the light opacity at different angles seemed to support that the material acts like it has a different openness at different angles and hence its permeability and sonic transparency would be affected. Fire straight through and get the full openness of the fabric, increase the angle and you're thereafter trading off acoustical transparency. After running through the tests with the Center Stage screen fabric, the measurements didn't support this. If you're wearing a tie, your summary is that the Center Stage screen doesn't perform worse at increased speaker angles, and that comb filtering is not significantly affected by speaker angle.

Doesn't help you saw holes in the wall though.
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post #167 of 170
9/11/10 at 12:31pm
Quote:
Originally Posted by BIGmouthinDC View Post

I have two inches of linacoustic on the front wall, The side columns are faced with 1 inch under the fabric, The side walls have 1 inch.

thin absorption won't do much for low frequencies though - 1" is .08 efficient at 125 Hz, .25 for 2" - so I suppose wouldn't alleviate any boundary issues. (Insert customary Holoday Inn Express disclaimer)
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post #168 of 170
9/11/10 at 1:28pm
Quote:
Originally Posted by BIGmouthinDC View Post

Understood. Is your experience two channel or 7 channel listening?

Both.
Quote:
Originally Posted by BIGmouthinDC View Post

Behind a woven screen?

No.
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post #169 of 170
9/12/10 at 4:40pm
"Pity as all the controlled directivity designs I've used have universally sounded better toed in heavily with the horn/WG axis crossing in front of the listener."

alpha niner makes a good point. bigmouth, did you catch this one?
http://www.audioroundtable.com/PiSpe...ges/23369.html

"Its a null anyways and outside of wanting perfect measurements there isnt much about a null that hurts the bass."

the ceiling and the floor can suck out quite a bit and placement appears equidistant there. this is what i was talking about:
http://www.peavey.com/support/techno...ncellation.cfm

one big reason people like the 4pi type design is the performance through the mid-bass. hate to see a big suckout put a dent in the fun.
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post #170 of 170
9/12/10 at 7:58pm
Quote:
Originally Posted by BIGmouthinDC View Post

Depends on where you are sitting. I have 3 rows of seating and the mid point of woofer/horn is a few inches above the listeners ear in the middle row. I plan to bring them down a tad in my final set-up.

That empty cavity is just a 3 sided MDF box that I am using to elevate the middle channel temporarily until I build in my subs and maybe do a THX baffle wall. I have it totally stuffed with leftover bits and pieces of acoustical treatments.

I like a THX baffle wall. My center channel speaker is set up that way.
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AVS › AVS Forum › Audio › DIY Speakers and Subs › Anyone build Wayne Parham's Pi-4 speakers? Impressions?