Home » Sponsored » Pi Speakers » 4Pi - alternate compression driver mounting?
Re: 4Pi - alternate compression driver mounting? [message #95213 is a reply to message #94478] Sun, 06 February 2022 20:07 Go to previous messageGo to next message
areohbe is currently offline  areohbe
Messages: 20
Registered: May 2021
Chancellor
Went offsite so I could take my time and not worry about disturbing the neighbors. I heard a lot of "Is that aliens?!?" from the kids two houses down.

I ventured out to one of the quietest places in North America, a mall parking lot.

I'm feeling pretty good about this. There's still a little weirdness in the 1-2k range, but it was highly susceptible to the mic position. Maybe just reflection from the boom itself?

/forum/index.php?t=getfile&id=3015&private=0
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Re: 4Pi - alternate compression driver mounting? [message #95216 is a reply to message #95213] Mon, 07 February 2022 10:25 Go to previous messageGo to next message
Wayne Parham is currently online  Wayne Parham
Messages: 18362
Registered: January 2001
Illuminati (33rd Degree)

Oh, that's excellent! https://audioroundtable.com/images/thumbs-up.gif

I like what I see in the 100-400Hz region, which was really what I was most worried about because of the port change. But I'm no longer worried. That configuration works fine. That tells me that the junk we saw was a result of reflections in the back yard, which is completely understandable and expected.

As for the 1kHz to 2kHz region, I'm a little less worried about that 'cause I know what it looks like based on the fore/aft locations of the drivers and the crossover. Your vertical distance between woofer and tweeter looks to be a little greater than a stock build, but not so wide as to narrow the null angles too much. I expect that to all be fine.

But I would double-check the usual stuff that can cause symptoms like that. Check the connection polarity. It's "weird" on both the woofer and tweeter, in that the 2226H needs positive to black and so does the DE-250. So make sure they're connected right.

And of course, make sure the tweeter face is flush with the baffle and the microphone is on-axis, or at least within +/-20°, maybe +/-15° in your setup with the tweeter a little further from the woofer than stock. When the speaker is on its back, the microphone should be hung above the speaker a few feet away and between the woofer and tweeter. That's the center of the forward lobe. You can then move the microphone along the speaker's vertical plane to find the positions of the vertical nulls.
Re: 4Pi - alternate compression driver mounting? [message #95593 is a reply to message #94478] Fri, 06 May 2022 14:55 Go to previous messageGo to next message
areohbe is currently offline  areohbe
Messages: 20
Registered: May 2021
Chancellor
A rather distracting home purchase event put the brakes on this project for a bit. But, we're back!

Ended up encasing the compression driver and tweaking the dimensions a bit.

Still needs a proper finish and a few other details wrapped up, but I am pretty damn happy with how it came out.

I'll share more details about the build in a later post.

/forum/index.php?t=getfile&id=3058&private=0
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Re: 4Pi - alternate compression driver mounting? [message #95594 is a reply to message #95593] Fri, 06 May 2022 15:23 Go to previous messageGo to next message
Wayne Parham is currently online  Wayne Parham
Messages: 18362
Registered: January 2001
Illuminati (33rd Degree)

Your speaker looks great!
Re: 4Pi - alternate compression driver mounting? [message #95595 is a reply to message #94478] Sat, 07 May 2022 08:26 Go to previous messageGo to next message
Barryso is currently offline  Barryso
Messages: 179
Registered: May 2009
Master
Excellent looking speaker. It has an old Altec vibe to it.
Re: 4Pi - alternate compression driver mounting? [message #95600 is a reply to message #95595] Mon, 09 May 2022 05:58 Go to previous messageGo to next message
Rusty is currently offline  Rusty
Messages: 803
Registered: May 2018
Location: Kansas City Missouri
Illuminati (2nd Degree)
Agree with Barry. That is a very nice interpretation. More pictures please!
Re: 4Pi - alternate compression driver mounting? [message #95610 is a reply to message #95600] Wed, 11 May 2022 15:11 Go to previous message
areohbe is currently offline  areohbe
Messages: 20
Registered: May 2021
Chancellor
Rusty wrote on Mon, 09 May 2022 05:58
Agree with Barry. That is a very nice interpretation. More pictures please!
Appreciate the comments, Rusty and Barry. I do love old Altecs. Smile

I'll share more photos as I have time. Up against a time crunch currently. Sad

(These speakers were supposed to go in my living room. But about a month ago, a friend that runs a non-profit, radio station in the Bay Area reached out to see if I could help them with sound for their new studio space. So, I'll have to be patient. But, worth the wait.)
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