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Re: 4pi build with stands finally realized [message #94426 is a reply to message #94425] Tue, 14 September 2021 06:03 Go to previous messageGo to next message
Roger S. is currently offline  Roger S.
Messages: 15
Registered: September 2021
Location: Norway
Chancellor
Final results.
/forum/index.php?t=getfile&id=2840&private=0
Woofers installed. I have one question regarding the woofers. These are 2226H which I bought used, and I believe they are original and imported from USA. But the cone and dustcap has a brown colour, and all the others I see on pictures are grey/charcoal. So are they reconed with non o.e.m. cones, or is it an early production? I hope some of you guys can chime in on this.
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Happy with the speakon solution on the bottom. Makes the rear a ot cleaner.
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Had to make some grilles too. Wanted a more factory finish, and I thought my wife would find them less intrusive too. This is our main living room so I wanted them to look as nice as possible. The grille is made as small as possible. The frame is not going inside the woofer gasket and allows for 8mm excursion before it touches the fabric. They are now hanging on the woofer gasket, but I have ordered small neodym magnets. These will be glued to the gille frame and sticks to the bolt heads for the woofer.
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Re: 4pi build with stands finally realized [message #94427 is a reply to message #94426] Tue, 14 September 2021 07:04 Go to previous messageGo to next message
Roger S. is currently offline  Roger S.
Messages: 15
Registered: September 2021
Location: Norway
Chancellor
Will try to do a soundcheck today, but work is calling, and I will be away 14 days. You see the rest of my system in the background. The 4pi's will be matched to the 21" subwoofers in the corner. They are Precision Devices PD2150 tuned to 18Hz, driven by a bridged Crown K2. I have used this setup for years now, and its a really fun combo. They are not flanking subs as they are positioned now, but I am going to try that when I come home. I have another K2 used for midbass duty on my former fully active setup, and a Crown Ct-4150. The plan is to run the woofer with the K2, and tweeter with 2 channels from the Ct-4150 as this has 10db better S/N ratio and it sounds really smooth. Proper gain matching between the amps will of course be done.
I have a minidsp Studio as preamp with Dirac. This is connected to minidsp 10x10HD, which will be used as dac for a while. Listening impressions and measurements will be posted when I find the time. The build started three weeks ago, and a lot of hours are spent. I am really looking forward to hear them, but from what I see from the measurements, rewievs and thorough documentation from Wayne, I am pretty confident they sound nice. Small adjustments in tonal balance can easily be done with dsp. Properly integrated drivers and good power response like in the 4pi is what I look for in a speaker. Poor engineering can not be fixed by dsp/room correction as some tend to believe. Tonal balance is easy.
Many thanks to Wayne and other builders for design and inspiration, and I hope this build will inspire others too.
I will be back with more when I have done some testing Smile
Re: 4pi build with stands finally realized [message #94428 is a reply to message #94427] Tue, 14 September 2021 09:18 Go to previous messageGo to next message
Rusty is currently offline  Rusty
Messages: 666
Registered: May 2018
Location: Kansas City Missouri
Illuminati (1st Degree)
Whew!! Stunning craftsmanship. Your work reminds me of Troels Gravesen, the Danish speaker builder. When you get all that dialed in, you'll have a system that would cost many multiples of what you put into your excellent DIY work. And sound even better.
Re: 4pi build with stands finally realized [message #94429 is a reply to message #94428] Tue, 14 September 2021 10:55 Go to previous messageGo to next message
Roger S. is currently offline  Roger S.
Messages: 15
Registered: September 2021
Location: Norway
Chancellor
Thanks for the kind words. It is really satisfying to make a plan and see it come alive. The result is just what I hoped it would be so far. D.i.y is way more rewarding than just buying and swapping out stuff.
This is my plan for "flanking" subs. I can squeeze the electronics in the middle. Looks way better, and allows me to cross the subs a bit higher too.
/forum/index.php?t=getfile&id=2848&private=0
Re: 4pi build with stands finally realized [message #94430 is a reply to message #94429] Tue, 14 September 2021 11:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18167
Registered: January 2001
Illuminati (33rd Degree)

Those speakers look great, and I'll bet your setup sounds great too.

As for the 2226H drivers - you said they were used and asked if they looked like they had original cones - it's really impossible to say. They are dark grey when new, with black surrounds and black adhesive around the dust cap. But depending on how much sunlight exposure they've had, I've seen 'em get nearly white and sometimes sort of brown. They usually just get lighter and lighter grey.

The thing is, I've also seen non-OEM cones that looked nearly original. Some are decent and some are terrible. You just can't know without measuring them. The good news is that even if the cone isn't original, you can always have them re-done with OEM parts and expect them to be 100% good as new.

I'm crossing my fingers for you that measurements prove them to be OEM cones. The place to watch is 500-1000Hz. An OEM cone will measure the same as what you see posted on the website.
Re: 4pi build with stands finally realized [message #94448 is a reply to message #94430] Sat, 18 September 2021 13:08 Go to previous messageGo to next message
alexg is currently offline  alexg
Messages: 10
Registered: June 2019
Chancellor
Speakers look awesome. I hope you are enjoying them.

How did you handle corners on your recessed horns?

Thanks,
Alex
Re: 4pi build with stands finally realized [message #94456 is a reply to message #94409] Sun, 19 September 2021 09:05 Go to previous messageGo to next message
Barryso is currently offline  Barryso
Messages: 153
Registered: May 2009
Master
Those are superb. Just a fantastic build.

Enjoy them!
Re: 4pi build with stands finally realized [message #94534 is a reply to message #94448] Fri, 01 October 2021 04:01 Go to previous messageGo to next message
Roger S. is currently offline  Roger S.
Messages: 15
Registered: September 2021
Location: Norway
Chancellor
Finally back from work today. I recessed the horns by making a template like this:
/forum/index.php?t=getfile&id=2861&private=0
There was a follower/guidebushing accessory for my handheld router. I made the straight lines in the template first using the router, and stopped before the arc started. Next I drew an arc for the corners by hand. I made it slightly too tight, and opened it up by using a dremel and sanding paper. I guess there are several ways to do this depending on what tools you have available, and it it time consuming for sure. The horns may be sightly different in size, and it may be easier to sand off the corners on the horn itself for the final adjustment:)
Re: 4pi build with stands finally realized [message #94535 is a reply to message #94409] Fri, 01 October 2021 04:21 Go to previous messageGo to next message
Roger S. is currently offline  Roger S.
Messages: 15
Registered: September 2021
Location: Norway
Chancellor
I was not sure if the woofers were original or reconed, so I took some raw measurements of the JBL 2226H. I did not find raw measurements on this site, but found several on the net. I think they look quite similar, but would like Wayne or others to have a look for peace of mind. I bought them used, and the seller was kind enough to provide impedance measurements on request (free air) before I bought them. REW measurements are done at 1m on axis.
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Re: 4pi build with stands finally realized [message #94536 is a reply to message #94535] Fri, 01 October 2021 08:38 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18167
Registered: January 2001
Illuminati (33rd Degree)

It's hard to say from your response chart, because it looks like a mix of on-axis and off-axis, e.g. power response. Were you measuring indoors, perhaps?

If so, measure outdoors or setup your equipment for a pseudo-anechoic measurement. Place the microphone directly on-axis around two or three feet away from the cone. Do this on a baffle or in a cabinet so reflections from the rear of the cone don't interfere with the sound emanating from the front of the cone.

To be honest, I'm worried about that notch at 1.3kHz because I see a lot of substandard cones get weird in that area. The aftermarket cones don't do well above 1kHz. But before we get worried about that, let's make sure you have good measurements because a lot of other things can cause that dip too. Could be self-interference from reflections or from the back-wave or both.

If you measure outdoors, or if you use gating to create a pseudo anechoic chart, what you should expect to see on-axis is rising response between 800Hz and 1.6kHz, and rolloff above that. On-axis, there's with a sharp dip around 2.6kHz. When you go far off-axis, at 45°, response starts to fall above 500Hz. It's down 3dB around 800-1000Hz and 6dB around 1.2kHz. Above that, it falls off rapidly, punctuated by a sharp dip around 1.3kHz.

The JBL spec sheet shows what you can expect to see from the raw driver:
And the four π loudspeaker measurements show what you can expect to see from the system:
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