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Paraflex Outdoor Measurements
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KaphaSound View Drop Down
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    Posted: 06 July 2022 at 11:34pm
Any thoughts on these recent Paraflex measurements? From a post in the FB group, outdoors at 1W/m without filters. Original:

“Some measurements I took outside...
Paraflex Type-C-Cram-218
Paraflex Type-C-Classic-118
Paraflex Type-R-121
Paraflex Type-R-118
Paraflex TC2E-GF-118 (early version)
Paraflex TC2E-115
Xoc1 TH118

TR-121:  18S 21NTLW5000-4
TR-118:  P-Audio 18-8 OEM custom
TC2E-115:  Oberton 15XB700-8 (now called 15XB1000)
TC2E-118: B&C 18DS115-8
TC-CRAM-218:  Oberton 18XB1500-8 (2x = 4 Ohm)
TC-Classic-118:  Oberton 18XB150008
XOC1-TH118: Oberton 18XB15000-8 / B&C 18SW115-8

You need to subtract 6dB from the CRAM-218 (purple) to compare to all the single 18s. The  Type-R-118 (orange) looks a bit hot since i took this with 1kHz sin-wave calibration. instead of 40Hz sin. Which resulted in hotter voltage on lower ranges. 

I left it in the graph since there is a noticeable difference in output when calibrating spl/voltage on 1kHz OR 40Hz.  I think it is a nice topic to discuss about it. 😆”





Edited by KaphaSound - 07 July 2022 at 12:03pm
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Xoc1 View Drop Down
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Points: 397 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 07 July 2022 at 8:25pm
Interesting Graph.
2 questions....
Would a longer distance than 1m be useful for the measurement if practical?
Could you state the volume of each cabinet as that would be very useful.Thumbs Up
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Points: 1083 		Post Options Post Options   Thanks (0) Thanks(0)   Quote fatfreddiescat Quote  Post ReplyReply Direct Link To This Post Posted: 07 July 2022 at 8:34pm
Thanks for sharing, re cal for signal, what are you using to measure signal level?
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Points: 1843 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 08 July 2022 at 7:39am
Not his measurements....... info taken off Fb
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it's quite amazing that hundreds of paraflex have been built seemingly without anyone taking some half-decent measurements. need to be done at 10m 28.3V (or 4m 11.3V at least). and it would be good to see the distortion plots for this design as a lot of the perceived volume could be coming from harmonics.
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Originally posted by KaphaSound KaphaSound wrote:

there is a noticeable difference in output when calibrating spl/voltage on 1kHz OR 40Hz.  I think it is a nice topic to discuss about it.




If this is the case, the measurement setup and method are incorrect - before we consider the fact the mic is in the acoustic nearfield, and the effect this has on the low-end response.
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KaphaSound View Drop Down
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Points: 102 		Post Options Post Options   Thanks (0) Thanks(0)   Quote KaphaSound Quote  Post ReplyReply Direct Link To This Post Posted: 08 July 2022 at 5:17pm
Just confirming these are in fact not my measurements but rather taken directly from the FB group. OP was “Plippie Plop”.

Does anyone have a good resource or explanation on why nearfield vs far field makes that much of a difference? I’m assuming it has something to do with the sound wave not fully leaving the boundary loading or something to that effect?

Personal thoughts are actually that these were better responses than expected but also fall short of some of the hornresp plots usually posted. I’m sure they are still solid DIY plans but certainly not vastly outcompeting the usual designs in FR vs SPL at least. They also seem quite heavy. Agreed that it’s bizarre these are only just coming out and personally I don’t believe they live up to the hype BUT they are a unique design and can definitely be considered “competitive”


Edited by KaphaSound - 08 July 2022 at 5:23pm
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Points: 462 		Post Options Post Options   Thanks (0) Thanks(0)   Quote djkeet Quote  Post ReplyReply Direct Link To This Post Posted: 09 July 2022 at 3:02pm
Yes the designs are not new ie 1/4 Wave, Compound etc, and from reading real world reviews they may require a fair bit of processing, I have to admit I do like the mid high designs. If I had my way l would have a warehouse full of different designs
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Points: 10919 		Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 09 July 2022 at 6:42pm
Originally posted by KaphaSound KaphaSound wrote:

Just confirming these are in fact not my measurements but rather taken directly from the FB group. OP was “Plippie Plop”.

Does anyone have a good resource or explanation on why nearfield vs far field makes that much of a difference? I’m assuming it has something to do with the sound wave not fully leaving the boundary loading or something to that effect?

Personal thoughts are actually that these were better responses than expected but also fall short of some of the hornresp plots usually posted. I’m sure they are still solid DIY plans but certainly not vastly outcompeting the usual designs in FR vs SPL at least. They also seem quite heavy. Agreed that it’s bizarre these are only just coming out and personally I don’t believe they live up to the hype BUT they are a unique design and can definitely be considered “competitive”





The acoustic centre is not at the grille for a subwoofer. Even if it was, you need to be in the acoustic far-field for the inverse distance law to begin holding true.

If you want to look up papers on the acoustic centre, use the American spelling "center". Or just find Vanderkooy's epic paper - which he didn't technically need to write, since all the info was out there already just with a non-Canadian English spelling 🙃

This might also help highlight why these measurements are pretty much useless for comparison purposes.
https://www.prosoundtraining.com/2010/06/28/far-field-criteria-for-loudspeaker-balloon-data/
https://www.artalabs.hr/AppNotes/AN4-FreeField-Rev03eng.pdf

I have shared these before, but those guys seem happy in their ignorance sadly.

Edited by toastyghost - 09 July 2022 at 6:43pm
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KaphaSound View Drop Down
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Points: 102 		Post Options Post Options   Thanks (0) Thanks(0)   Quote KaphaSound Quote  Post ReplyReply Direct Link To This Post Posted: 11 July 2022 at 4:35am
Thanks for sharing Toasty! Will read through, I’m assuming the measurements at 10m would likely demonstrate a worse response? Do you know if hornresp plots are more likely to match up with the 1m or 10m real world measurements?

Another thought I had which may not ring true is that surely loading different parts of the same driver as is the case in paraflex models should cause more distortion due to (very unscientific term) wobbling in the cone? Sure if the driver was a cinder block it wouldn’t deform much but I can only imagine especially at high SPLs the pressure differences on each side of the cone would cause at-least slight imbalances?


Edited by KaphaSound - 11 July 2022 at 4:39am
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sarsen1 View Drop Down
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Despite the incorrect measurements methods used here, is the graph still useful for comparison purposes between boxes or does it mean that frequency response is inconsistently inconsistent so basically useless?
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Points: 10919 		Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 12 August 2022 at 1:45pm
Originally posted by sarsen1 sarsen1 wrote:

Despite the incorrect measurements methods used here, is the graph still useful for comparison purposes between boxes or does it mean that frequency response is inconsistently inconsistent so basically useless?




The latter.
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