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Re: 4 Pi Build Progress [message #81583 is a reply to message #81462]

Mon, 21 September 2015 10:23

rvsixer
Messages: 58
Registered: February 2011

Baron

That setup looks AWESOME, and thanks for the initial listening report.

I didn't know you where also building 3pi's. When they are finished please share your thoughts 3pi vs 4pi. I have all the parts for 3pi's, but the 4pi's keep calling my name (only the price of the 2226's keeps me away) Confused

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Re: 4 Pi Build Progress [message #81584 is a reply to message #81583]

Mon, 21 September 2015 10:59

BobTahoe
Messages: 32
Registered: July 2015
Location: Lake Tahoe , NV

Baron

Woops, I should have said 3pi subs.

Although though the woofers in those old speakers are the Delta-12LF which I believe is the base 3pi woofer. First I have to get/build proper speaker stands.

I bought my 2226h's on ebay. picked up 2 pairs, 1 out of four was a very obvious recone. 2 of them looked original and older but sound fine and the center channel is a 2226hpl which from what I understand is a 2226h oem meaning it originally came in a JBL Cab, which matches the story. In the end I paid about $600 for all 4 and was able to use 3. Eventually I'll use the Spare and get it rebuild. If buying new I'm almost positive Wayne has the best deal. Unless you catch a good sale at parts-express which is how I picked up the B&C DE250s.

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Re: 4 Pi Build Progress [message #81587 is a reply to message #81462]

Tue, 22 September 2015 08:37

rvsixer
Messages: 58
Registered: February 2011

Baron

Okay I see now...I should have noticed those were 3pi subs in the pic.

I found a pair of 2226HPL on CL yesterday, trying to work a deal on them.

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Re: 4 Pi Build Progress [message #81594 is a reply to message #81462]

Wed, 23 September 2015 15:37

BobTahoe
Messages: 32
Registered: July 2015
Location: Lake Tahoe , NV

Baron

Ok I'm pretty sure I'm doing something wrong here either taking the measurements or I wired all the DE250's out of phase maybe?

This is the Left, then Right Speaker. The mic was several feet further from one speaker then another due to USB wire length.

Here are my measurements. This is in room of course.

Attachment: 4pi test 1.png
(Size: 62.20KB, Downloaded 4019 times)

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Re: 4 Pi Build Progress [message #81595 is a reply to message #81594]

Wed, 23 September 2015 15:56

BobTahoe
Messages: 32
Registered: July 2015
Location: Lake Tahoe , NV

Baron

I've tested them both ways and the graph doesn't look much better.

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Re: 4 Pi Build Progress [message #81596 is a reply to message #81595]

Wed, 23 September 2015 17:57

Wayne Parham
Messages: 18783
Registered: January 2001

Illuminati (33rd Degree)

I'm suspicious of the measurement system. If you had a driver mis-wired, you'd see a hole around 1.2kHz. So it's not that.

I see a big hole around 5kHz, and it's pretty much the same in both traces. However, if that were a compression driver problem, I'd expect it to be in one but not the other. So I doubt it's the driver.

It looks like one measurement trace one is shifted in frequency with respect to the other by about 10%. Where one shows a feature at say 5kHz, the other shows the same feature at 5.5kHz. Where one shows something at 42Hz, the other shows the same thing at 47Hz. So the anomalies appear to be the same in both traces, but for some reason, they're shifted in frequency by 10%. That's an odd set of symptoms.

I think the anomalies are probably caused by the measurement system. It's the only thing I can see that would cause this.

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Re: 4 Pi Build Progress [message #81600 is a reply to message #81462]

Sat, 26 September 2015 08:39

skywave-rider
Messages: 104
Registered: May 2009

Viscount

Irrespective of the anomalous frequency shift Wayne mentioned, the only time I have gotten issues like this was when I was running both speakers simultaneously and taking measurements. The only way that works is if the microphone is just about exactly between the monitors. As you've stated, your microphone was significantly off. Do you think it was possible you had both running, or one only partially reduced in volume? In my attempts to center the mic I found that the further off center, the lower the frequency of cancellation. This may not be your problem but check it if you haven't.

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Re: 4 Pi Build Progress [message #81603 is a reply to message #81600]

Tue, 29 September 2015 15:30

BobTahoe
Messages: 32
Registered: July 2015
Location: Lake Tahoe , NV

Baron

Yeah I believe I did have them both on. I'll try to redo the tests soon and see if I can get the sound card on the computer I'm using calibrated too.

I just had one of the 2226h's give out on me (it just started sounding scratchy) and had to swap it out with the one I was trying not to use because it was clearly rebuilt and possible with non JBL parts. So I want to test that woofer anywise while I send the blown one out to get rebuilt.

Thanks for your help. I'll post some more results soon I hope.

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