Yeah ground plane, misspelled it. Since the devices are rather large, you should do the ground plane measurement rather far away as well to get as "on-axis" as possible.
Us hobbyists easily get some error no matter what, but that's fine. You can try to estimate how much of an error there is and then decide if it's a problem or not. For example, measure with few different ways, inside, outside, various distances, various equipment. Point is to get your trust on your data, which you currently lack. Doing more measurements hopefully reduces error and gives you confidence to rely on what you've got.
Us hobbyists easily get some error no matter what, but that's fine. You can try to estimate how much of an error there is and then decide if it's a problem or not. For example, measure with few different ways, inside, outside, various distances, various equipment. Point is to get your trust on your data, which you currently lack. Doing more measurements hopefully reduces error and gives you confidence to rely on what you've got.
In that case the measurement distance is fine I think. I would try and measure multiple times, moving the mic some to scope if sound changes there about at listening position and how much. Perhaps average the measurements for EQ or something. Main idea is to get familiar with what the sound is like that close, and how much it varies.
@gedlee @weltersys @GM
Is it weird to have the think about room gain in your tweeter XO 😉
(inside at 46")
(Outside on the deck 6 ft from house pointed at sky, 1meter, too lazy to go to middle of yard...)
Thd measurements are more accurate outside it seems. According to the above I have more than enough headroom to cross at 200hz, wouldn't you say?
Is it weird to have the think about room gain in your tweeter XO 😉
(inside at 46")
(Outside on the deck 6 ft from house pointed at sky, 1meter, too lazy to go to middle of yard...)
Thd measurements are more accurate outside it seems. According to the above I have more than enough headroom to cross at 200hz, wouldn't you say?
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If you are now happy with 18% third harmonic distortion at 233 Hz and below at 109 dB from 1 meter away, sure, you have enough headroom 🙄 .
I can sing louder than that, but who cares...
Yes, since I give almost no credence to the concept of "room gain." Almost all of the explanations that I have read about this concept are wrong.
Lotsa suger there ;-) - way to much distortion for my liking and requirement. About at least 10x too much.
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"Is it possible to cover the whole spectrum, high SPL, low distortion with a 2-way?"
Yes, it is, but not using the approach Camplo decided to use 😳 .
Thank you for being forthright but lets take a measurement at a more realistic spl. Was that an honest 115db?
I call that a show of force. Thd is complicated with horn loaded drivers. I recall times where THD would lower as I moved the microphone closer... That suggest a disconnect between the measured thd and parasitic effect to the rest of the passband, which is it what I would be concerned about, as I do not recall any issues with impressions of SQ.
Your liking is a system producing less than 2% thd at 117db/1m?????? What system do you have!? Please share your measurements at 117db/1m
I dont have a 117dB system. But if I was to design one, those would be my requirement. BMS 18" bass to begin with... and it would a 3 way system. But I would set up requirement first and then see how many "ways" it takes - not the other way around. This must surely have been discussed in the thread I suppose.
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I hate to be sarcastic, but this whole discussion seems to have become "disconnected" from reality. Its full of dimensions on numbers that make no sense (95rms/1m.), completely undefined and unclear "effects" and a little of "well it sounds good to me." Not very scientific.
Btw about measurements. If considering non distributed subs (because family peace sometimes winns on science) but only a two ways like you also did, what is the minimum f3 and f10 low limits frequency you are confortable with for music purpose (no HT), please ? (Understand in the rooms you live in)
I remember some from Patrice Batman inputs his Suma (15" woofer) could be too much bass in small spaces or small living rooms, if am close enough to what he said.
Maybe an off topic question related to high spl needs for PA purpose of the op. I appologize for that, I am more an average spl level music listener.
I know the answer can only be an approximation without acurate measurements of room gain, but most never measure it.
I remember some from Patrice Batman inputs his Suma (15" woofer) could be too much bass in small spaces or small living rooms, if am close enough to what he said.
Maybe an off topic question related to high spl needs for PA purpose of the op. I appologize for that, I am more an average spl level music listener.
I know the answer can only be an approximation without acurate measurements of room gain, but most never measure it.
You'd be surprised how satisfying a rolloff at 70Hz can be, if everything else is carefully balanced.
I surmise if treble roll off is shorter as well ? That is interresting because it could mean according the age of your ears you need different designs !
Sorry Camplo for the off topic. Just a last. Allen, is a F3 55 hz , F6 40 hz, F10 35 hz are good enough or it must be corelate to the treble section roll off and or the room (I try to read you between the words) ?
Sorry Camplo for the off topic. Just a last. Allen, is a F3 55 hz , F6 40 hz, F10 35 hz are good enough or it must be corelate to the treble section roll off and or the room (I try to read you between the words) ?