Аудио-википедия

https://www.diyaudio.com/forums/multi-way/233045-ae-speakers-dipole-15-lo15-advice.html
https://soundex.ru/forum/index.php?/topic/31768-open-baffle-%D0%B0%D0%BA%D1%83%D1%81%D1%82%D0%B8%D0%BA%D0%B0/

Acoustic Elegance

LO15

IB15

Eminence

Alpha 15A

Pure Audio Project

OB-A15neo

https://www.audiocircle.com/index.php?topic=122661.0

My listening room is quite small, approx. 13.8 x 10.8 x 7.9 ft. Now I have a simple plain baffles with TB W8-1808 + Fane sovereign 18-500 (18«). I have also tried Eminence alpha 15A instead of Fane, but it's not any better. I like the sound in general, but the bass quality is not as good as I could wish for. It's maybe too slow and does not have shades like the best ones.

My amplifier is Vincent sv-236 mk:
http://www.6moons.com/audioreviews/vincent2/1.html

and cd-player is Arcam cd33:
http://www.stereophile.com/cdplayers/704arcam/

Let me tell you shortly about my DIY history:

About 5 years ago I had Dynaudio Focus 140 loudspeakers. I liked them. (Overall balance was well suited for hard rock music. I still listen to lots of rock but also jazz and many other genres). But there was a problem with room modes.
Lowest mode, about 41 Hz, had a high peak and it was disturbing too much. I sold Dynaudios.

After that I heard about MJK and I decided to build TB W8-1808 + EA 15A baffles. It was a big improvement. Bass problems had gone away, midrange area was shining. They also worked pretty well with rock music, so I was happy quite a long time.

Later I needed something to do. I build Pencil 12 cabinets with Markaudio Alpair 12 elements, just to experiment something else. Thet were working very well with highest quality recordings, but if I put something ugly heavy metal it was terrible to listen. But I liked the bass quality very much. It was a little bit thin but otherwise very good. Also Pencils had to go.

After that I built MJK's H-frames with my current Fane 18» elements. It was not successful. I don't know what's the problem with H-frame construction, but it's not working at all in my room. Maybe my room is too small and/or maybe listening distance is also too small. Soundstage was way too obscure. Not good.

So nowadays I'm using plain baffles, approx. 70 x 90 cm, with TB + Fane. They are tilted backwards 5-6 degrees. This is the best solution so far.

Based on the bass quality of Alpairs and what I have heard/read about single FR drivers, I would like to experiment with a single driver. Maybe a bigger plain baffle or a winged version. Unfortunately I don't have much time for experiments, too many things to be done, so all ideas are welcome.

Вот хорошая статья - измерения в щите, U фрейме и H фрейме.

Прекрасно видно смещение резонанса, наклон АЧХ 6дб/октава, гребенку и снижение отдачи.

http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf

Обычные рекомендации: « The maximum length of the U and H frame geometry should be sized so that the first quarter wavelength resonance occurs above the low pass crossover frequency»

То есть, если мы планирует резать на частоте 300Гц, длина трубы не должна превышать 0,28м (с каждой стороны), если 150Гц - уже 60см можно сделать.