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Re: Pete's Home Theater Build [message #76959 is a reply to message #68358] Wed, 05 June 2013 22:35 Go to previous messageGo to next message
petew is currently offline  petew
Messages: 63
Registered: June 2011
Location: Albuquerque, NM USA
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Teaser shot here. I'm making good progress on the project.

index.php?t=getfile&id=1187&private=0
Re: Pete's Home Theater Build [message #76960 is a reply to message #76959] Thu, 06 June 2013 01:28 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17913
Registered: January 2001
Illuminati (33rd Degree)

Excellent, Pete. Thanks for posting the pics here.

Just for curiosity's sake, what is your room layout? Where are your speakers going?

I ask because I found an odd but neat trick for my side surrounds. I wanted to place them beside and slightly above and behind the listeners, much like they are in theaters. But my room layout didn't really support that - The best place to put the side surround speakers was behind the listeners.

So I tried aiming them at the side walls, where the angle of reflection directed their sound into the listening area, approximately towards the same place where the forward axes of the L/R front mains cross. Turned out excellent! It's spooky good that way. People are always looking around, thinking stuff is happening outside or off in the other room and then realize it's in the movie soundtrack. Cool

I'm wondering if that might not work well for your too. You can always mount the side surrounds on the side walls facing inward, but maybe try them in this reflected mode and see how you like it too. If you like how it sounds, then the sides and the rears can be put in the same place, but the sides directed at the side walls while the rears are directed straight forward.

If you try that, report back and let me know what you think. Maybe live with it for a few movies each way to see.

Re: Pete's Home Theater Build [message #76966 is a reply to message #76960] Thu, 06 June 2013 13:37 Go to previous messageGo to next message
petew is currently offline  petew
Messages: 63
Registered: June 2011
Location: Albuquerque, NM USA
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Here's a layout of my room. Current side surrounds are old B&W towers, the rears are bookshelf speakers on top of two drawer lateral file cabinets.

index.php?t=getfile&id=1188&private=0


I was planning to wall mount the 2π surrounds in the same locations, but at 6' or so above the floor angled slightly downward.

Re: Pete's Home Theater Build [message #76970 is a reply to message #76966] Thu, 06 June 2013 18:54 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17913
Registered: January 2001
Illuminati (33rd Degree)

I can certainly see why you want six π cornerhorns for mains. That room is perfect for them.

Are you planning to put the side surrounds on the subs? Or maybe hung on the walls above them? Looks like that's where they would work best.

Re: Pete's Home Theater Build [message #76978 is a reply to message #76970] Fri, 07 June 2013 12:42 Go to previous messageGo to next message
petew is currently offline  petew
Messages: 63
Registered: June 2011
Location: Albuquerque, NM USA
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I'll be mounting the surrounds on the walls with the bottom of the cabinet at about 5'. I'm going to play around with placement before I build the wall mount brackets.
Re: Pete's Home Theater Build [message #76979 is a reply to message #76978] Fri, 07 June 2013 13:35 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17913
Registered: January 2001
Illuminati (33rd Degree)

Sounds like a great plan. I think that's what I would do too.

Are you still planning to run constant directivity cornerhorns? Or are you going back to your original plan of using four π mains? The cornerhorns would be perfect for that room, but one advantage of the four π's is you can put 'em just about anywhere. The subs where you've shown will reduce self-interference from nearest boundaries if you blend them with the mains. So that's a good setup too.
Re: Pete's Home Theater Build [message #76980 is a reply to message #76979] Fri, 07 June 2013 14:16 Go to previous messageGo to next message
petew is currently offline  petew
Messages: 63
Registered: June 2011
Location: Albuquerque, NM USA
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I'm definitely going with corner horns. Have not decided between the six and seven yet though. I'm working out the details on the mid-horns and plan to build them soon.

I know you've recommended using a three or four for center channel duty. What would you think about using a mid-horn, HF horn and crossover from a six or seven as the basis of a center channel speaker? I'd build a bass bin to fit the space available behind and below the screen. The seven bin would fit my space but obviously wouldn't have the benefit of living in a corner.

It might make sense to bi-amp the bass bin on one amp and the [mid+HF+passive XO] on another amp with a miniDSP active XO.

It seems that the LF driver in the corner horns covers a much smaller chunk of spectrum than the LF driver in a three or four. I'm concerned (obsessed) that the center blends seamlessly with the left and right corner horns. Since the range covered by the mid-horn is so important I'd think all three front speakers would be better matched up from mid bass to the top end with identical drivers.
Re: Pete's Home Theater Build [message #76981 is a reply to message #76980] Fri, 07 June 2013 15:04 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17913
Registered: January 2001
Illuminati (33rd Degree)

That's an excellent question, one that has been posed here many times. I think that the method you propose will work well, and there are plenty that have done it that way. In fact, if I did not have experience with the sound of a three or four π center combined with six or seven π cornerhorns as mains, I would probably think the midhorn proposal you make for the center channel would be the right way to go. And it isn't like that's the wrong way to go, so you can certainly do it if you want to.

But the thing is the spectral balance is similar with each of these speakers, so they do sound matched. I would probably use a DI-matched two-way even if my left and right mains were constant directivity cornerhorns. Mostly that's because I know the speakers are already vetted out, tested and optimized. No surprises that way.

The biggest difference is in the room/speaker interface, to tell the truth. The constant directivity cornerhorns having no self-interference, the wavefront launch from the corners and the truly constant directivity throughout the band are things you cannot match with any other configuration. So even if you put a midhorn in the center channel, it's still different than the cornerhorns.

Still, don't let me discourage you. You can do exactly what you've described and it sounds very good, matched and clean. Lots of people here have built four π cabinets as bass bins and put midhorns and waveguides on top, just like you've described. The midhorn and tweeter need to be attenuated about 3dB when done this way. Basically, you use the woofer circuit from the constant directivity cornerhorn schematic, but the tweeter circuit uses R1/R2 values shown for the corresponding DI-matched two-way. And the midhorn resistors must be changed from R4=4Ω and R5=8Ω to R4=5Ω and R5=4Ω.

Either way - center channel being a DI-matched two-way speaker or a hybrid with midhorn - the sound is very good. It sounds natural when things pan across the front channels, through the center. The illusion is maintained, largely because the speakers are all voiced the same.

Re: Pete's Home Theater Build [message #76986 is a reply to message #76981] Fri, 07 June 2013 22:09 Go to previous messageGo to next message
rkeman is currently offline  rkeman
Messages: 77
Registered: March 2010
Location: Florida
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The tonal and soundstage matching of the 6Pi and 3Pi is excellent, and I agree that developing a "new" center channel using the midrange and high frequency horns and some bass bin is less likely to yield as good results as using the matching two way and corner horn. I recently had an experienced audiophile friend comment on the seamless match between the three front channels is when he realized that he had chosen the Dolby Pro Logic II Music mode rather than stereo while listening to a vinyl record. What also amazed him was that the phono input was being digitized and processed using both Dolby and Audyssey room correction and it really sounded great!
Re: Pete's Home Theater Build [message #76994 is a reply to message #68358] Mon, 10 June 2013 16:58 Go to previous messageGo to previous message
petew is currently offline  petew
Messages: 63
Registered: June 2011
Location: Albuquerque, NM USA
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How is the tonal match if I used the JBL driver in a 4π and Eminence drivers in the 7π? My budget would be stretched using three JBL drivers, but I'd guess the upgrade is more important in the 4π since the 15" covers more octaves than in the cornerhorns with the midhorn.

Your advice is much appreciated.
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