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Just Loaded in 4 Pis [message #60888] Wed, 16 September 2009 09:51 Go to next message
skywave-rider is currently offline  skywave-rider
Messages: 104
Registered: May 2009
Viscount
Just loaded in 4Pis last night. This is a recording control room at a Uni. Only had a chance to listen for a few minutes. But impression is that these will work extremely well. Good looking speakers, too. Thanks, Wayne.

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Re: Just Loaded in 4 Pis [message #60891 is a reply to message #60888] Wed, 16 September 2009 15:49 Go to previous messageGo to next message
cookietruck is currently offline  cookietruck
Messages: 14
Registered: September 2009
Chancellor
those look great.
Re: Just Loaded in 4 Pis [message #60899 is a reply to message #60888] Wed, 16 September 2009 21:30 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18272
Registered: January 2001
Illuminati (33rd Degree)

I'm glad to see you have those speakers installed and running. Glad to hear your initial impressions are favorable. I'd love to read a more detailed review, if you wouldn't mind, when you've had a chance to live with them a while. I know how I feel about mine, but I also like hearing from others.

Nice looking studio, by the way. Thanks for posting the photo!

Re: Just Loaded in 4 Pis [message #60903 is a reply to message #60888] Thu, 17 September 2009 06:42 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
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Skywave Rider- that veneer looks sensational! That's one set up I'd like to hear as the centre speaker HF is Econo-Wave-correct? Selenium driver or DE-250? Would be fascinating to hear 4 Pi and the E/W-2226 side by side. Well done and congratulations on your project.
Re: Just Loaded in 4 Pis [message #60905 is a reply to message #60888] Thu, 17 September 2009 12:52 Go to previous messageGo to next message
skywave-rider is currently offline  skywave-rider
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Registered: May 2009
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Psychoacoustic,

Now wait a minute...what you see pictured are 4Pis ordered from and built by Pi Speakers, employing the JBL 2226H and DE250; and high quality crossover part options. I wish I could take credit for the build. Yes the wood looks great, it is birch.

You may be referring to the previous monitors I had installed in that location...that was temporary until the 4Pis were acquired. Those were developed from my original Econowaves and I am now stripping out the drivers for my home EWAVE setup.

The 4Pi speakers work extremely well as real recording studio control room main monitors. I have heard and used them all. The 4Pis are frankly an incredible bargain for their capability, capacity and compact size.

They are running off of a Bryston 4B and with a Genelec 7070A sub.

The center channel is waiting for an amp.

The room is designed by WSDG.

When I have had time to live with them, and hopefully do a project with them, I'll comment more.



EDIT: I just reread your comment...sorry, the center is 4Pi, but a custom version which I will let Wayne expand upon.
Re: Just Loaded in 4 Pis [message #60908 is a reply to message #60888] Thu, 17 September 2009 18:33 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
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Ah, yes. I can see the Eminence horn's six mounting holes now on the higher resolution monitor at work. The JBL/Pyle has eight, if I remember. The horn just looked a bit smaller, but I see that is due to it being set back a little.
Now even more intrigued- what does the centre channel do and why the different design... Look forward to reading your impressions, SkyWave.
Ant
Re: Just Loaded in 4 Pis [message #60910 is a reply to message #60908] Thu, 17 September 2009 19:09 Go to previous messageGo to next message
skywave-rider is currently offline  skywave-rider
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Registered: May 2009
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Ant,
The center is a sealed box version, no port, so the horn can be centered in the baffle, since it is a center speaker. The trade-off is that the low frequency rolloff begins sooner and will require some EQ to compensate. The response from the rolloff up should be identical to the standard L & R 4Pis.

Re: Just Loaded in 4 Pis [message #60913 is a reply to message #60888] Thu, 17 September 2009 19:50 Go to previous messageGo to next message
Wayne-o is currently offline  Wayne-o
Messages: 225
Registered: May 2009
Master
Nice finish on the cabinets !!!
Re: Just Loaded in 4 Pis [message #60915 is a reply to message #60910] Thu, 17 September 2009 20:37 Go to previous messageGo to next message
Matts is currently offline  Matts
Messages: 359
Registered: May 2009
Grand Master
Excellent looking setup! I'd like to hear it, too- the speakers look great mounted up in the walls. I'm also interested in hearing more about the center channel... I've got the same model 4's and couldn't be happier with them!
Re: Just Loaded in 4 Pis [message #60916 is a reply to message #60913] Thu, 17 September 2009 20:55 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18272
Registered: January 2001
Illuminati (33rd Degree)

The reason we made the middle speaker sealed for the university studio was that, as a center channel, purely for aesthetics, it simply looked better to have the tweeter centered. I think sometimes psychoacoustics are as important to listening impressions as anything else.

We rarely make custom speakers (no need, I feel we have something for every application) but in this case, a slight modification was done for aesthetics. I don't normally do mods because it really requires a design/test cycle to make sure there are no unintended consequences but in this case, I felt there was little potential for side effects. The specific design considerations are described below.

The slight offset of the tweeter in the four π loudspeaker cabinet is not enough to matter, less than 1/4λ and completely inaudible. You can't tell if the speaker is left or right, so it's purely an aesthetic thing what side you put them on. You could use either one as a center and be just fine. But it did seem to me that the middle speaker would look better with the horn centered.

The thing is, you can't physically fit the port on the baffle if the horn is centered. I suppose you could probably put it on the back or use a handful of smaller ports in the corners or something but like I said above, that would require a whole new design/test cycle to find out what the effect of relocating the port would be. In a cabinet this size, standing waves are starting to fall into the Helmholtz frequency region and port position becomes important.

Removing the port entirely is a different matter because the back wave is absorbed. It's a simpler system that limits the chances of unintended consequences. The woofer's electro-mechanical parameters allow it to be put in a sealed cabinet this size without becoming underdamped, so it was a viable solution. I think it is even a slight benefit because it staggers bass tuning between speakers, which helps distribute bass sound (modal) sources better. They're using a sub in this studio, so that brings the count of bass sound sources to four, which should provide a nice smooth sound field in the modal region.

Here's some information that may be interesting for the perfectionists and audio snobs out there. Smile I've mentioned this before, but maybe to glazed eyes. Or maybe I didn't mention it here, might have been in the Ewave thread on AK or the Horn/Waveguide thread on DIYaudio. Either way, I'll mention it again.

One thing I've noticed with the four π speaker (which is the only loudspeaker I've studied in great detail that has an offset tweeeter) is that the nulls are diagonal rather than directly above and below the speaker. Naturally, you might say, those of you who have studied and understand crossovers and the acoustics of multiple sound sources might expect this. But what you probably wouldn't have known (I certainly didn't until I moved the microphone around in about a thousand different XYZ positions) is that the nulls are thrown to the side, the maxima is not directly on the line drawn between driver centers. I wouldn't have expected this.

The nulls that form direcly above and below the speaker are mild. When you rotate the speaker so the tweeter is directly above the woofer, the nulls forming directly above and below that axis are still mild. The maxima forms about ten degrees past that. So with the speakers positioned on each side and toed-in as they usually are, the null maxima can be pointed further outside the target listening area. The upper null is roughly in line with the edge of the upper corner outside. The lower null is down towards the logo.

Now then, the nulls are so far outside the pattern it really doesn't matter. You can't hear a difference, no matter what side the speaker is placed. So you really can place them as you think they look best. But even still, I know where the nulls are from measurement, so I try and direct them where they are the least objectionable. The lower null is down on the floor and directed towards the opposite speaker. The upper null is over everyone's head and directed at the ceiling outside the pattern, both vertically and horizontally.

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