I was going to say; at those frequencies at 1m in a room you’re really measuring the interaction between the room, the box & the drivers but the awesome community here has already explained this in a much more eloquent and technically specific manner🙂
I believe this is a very common mistake, i.e. not fully appreciating the limitations of gated measurements in rooms. I have very much been there myself.
Taking those puppies out on the driveway or to the nearest baseball field for a groundplane measurement and hoisting them up to a couple of meters on a basketball court for measuring is not for the faint of heart.
Then it’s hauling them back to camp to process the numbers and changes to the huuge cab and/or filters and off again to measure. OK, you can always buy a Klippel NFS for megabucks but then you’ll find out that speakers like these won’t fit..
At the huge(ish) anechoic chamber, we are lucky to have access to, these bass cabs would probably not even fit through the doors of the lab, 🤣. If you get the behemoths through the doors you still have to balance everything on the turntable…
All this makes me wonder how much ‘proper’ measuring that’s involved in designing these mega horn systems..
I believe this is a very common mistake, i.e. not fully appreciating the limitations of gated measurements in rooms. I have very much been there myself.
Taking those puppies out on the driveway or to the nearest baseball field for a groundplane measurement and hoisting them up to a couple of meters on a basketball court for measuring is not for the faint of heart.
Then it’s hauling them back to camp to process the numbers and changes to the huuge cab and/or filters and off again to measure. OK, you can always buy a Klippel NFS for megabucks but then you’ll find out that speakers like these won’t fit..
At the huge(ish) anechoic chamber, we are lucky to have access to, these bass cabs would probably not even fit through the doors of the lab, 🤣. If you get the behemoths through the doors you still have to balance everything on the turntable…
All this makes me wonder how much ‘proper’ measuring that’s involved in designing these mega horn systems..
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As has been stated by others, that is not the real response of the Tad 1601/A/B or 03 at least.
1m measurement inside with 7 ms gating possible reflections, depending on distances.
Comb filtering from the horizontal config, also 4-500 hz is too high you will get plenty of combing etc unless 2.5 way config. The everests are a decent example to study.
And the obvious floor bounce cancellation often comes in this range.
Ill do the near field measurement
Many thanks. I'll look into it.
Can't know if this will help as your boxes are different, but Pierre has used those TAD woofers for years.
See his system here; posts # 15266, 15276.
https://www.diyaudio.com/community/threads/beyond-the-ariel.100392/page-764
And see post #47, where he said that the TAD woofer's sweet spot is between 725 and 775Hz.
https://www.diyaudio.com/community/...horns-measurements.395046/page-3#post-7253984
Note that if you really need to cross around 500Hz you might want to consider the GPA Altec 416-8B
Troy Crowe measured mine here and said the ideal is 500Hz.
https://josephcrowe.com/blogs/news/altec-416-8b-in-100l-sealed
However, depending on sealed or ported box size, it may be best to add subwoofers, which is what I'll be doing with those Altec 416s in 3 cu ft sealed boxes. For below ~ 86 db @ 70Hz, I will use two or more of these subs. https://www.rythmikaudio.com/F12.html
Hope this helps. 🙂