Not quite ready yet since just because this can work [and done it with Altecs], the larger horn will load it more, which in turn often requires reducing the rear chamber's net Vb, so do they offer a loading cap like Altec? I didn't find one in a quickie search.
GM
I do not have a loading cap on my Altec 288K. But i know that on smaller motors 80X it exist.
As far as I know contemporary drivers do not have (an optional) loading cap. These days loading isn't something that many manufacturers worry about, as most compression drivers are used with short horns.
AFAIK, none exists for the large format drivers. 😉 I mean it was designed to load an 18 cell, 300 Hz horn, so talk about under stressed in a typical HIFI/HT app!
Right, originally designed for the 500 Hz/511 AFAIK and later used on all 800 series, duplex as amp power dramatically increased in the '70s.
GM
Right, originally designed for the 500 Hz/511 AFAIK and later used on all 800 series, duplex as amp power dramatically increased in the '70s.
GM
Hence my concern, especially since I've seen no one using them on larger horns, lower XOs, though admittedly dropping a half octave in a HIFI/HT app isn't likely to be an issue, but like folks to be aware none the less.
GM
Struggling to find somewhere selling 1" to 1.4" throat adapter so can use 1" drivers onto the Altec MRII 564 horns!
Why not have one 3D printed to exactly suit the horn and driver angles?
One related question to the experts: how is the function of the diffraction slot influenced by making the horn longer with the adapter?
Lobing exists, you don't want it, then drivers need to be < 1/3 WL of the highest frequency to be reproduced for us not to hear it in our acute hearing BW.
Your eyes, ears are horizontally opposed, so vertically oriented sights, sounds have a narrow focus, hence not a lot of spacial information to work with; horizontally though, 'smearing' due to lobing, comb filtering is an increasing problem above the ~800 Hz head transfer function [HTRF].
Anyway, this is [one of] Dr. Geddes's fields of endeavor, so looking forward to any thoughts/corrections/whatever.
All I really know for sure is that this Altec 9844 studio monitor and its consumer model is one sweet sounding speaker if not too far off axis: altec 9844 - Google Search
Ditto this '50s era Altec 830A Laguna dual 15"/500 Hz corner system: Altec 830A Laguna - Google Search
GM
What about significant driver weight?
Altec's 21216 'universal' adapter dates to the original large format driver and just a short [3.125"] conical extension, so primarily just impacts the BW above ~ 5 kHz.
GM
Thanks for the information, IMHO high directivity horns are low-fi devices but unavoidable when a high directivity is required on a large frequency range.
This is a very good question.
AFAIK the inner workings of diffraction slots are very hard to desribe mathematically. IOW it's difficult to 'predict' the wavefront inside and after the slot at one particular frequency, let alone across the band.
Read Kolbreks thesis on 'mode matching' to find out. He couldn't really get passed the 'pinched throat' case, which is just one feature of some slotted horns. Modern diffraction slots are developed by use of computational techniques (FEA etc.).
I am looking forward to Dr. Geddes' reply, even though I am perfectly aware he 'doesn't like diffraction slots', to put it mildly.
Diffraction slots have their merits and they can work very well, if implemented with care. Earlier in this thread some examples were cited.
Here's another:
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Obviously: "Bjørn Kolbrek couldn't get past the pinched throat case" 😉
I also referred to the wrong thesis: "Extensions to the Mode Matching Method for Horn Loudspeaker Simulation".
The pinched throat is dealt with in his Master's thesis: "Modal sound propagation in curved horns of rectangular cross-section".
I also referred to the wrong thesis: "Extensions to the Mode Matching Method for Horn Loudspeaker Simulation".
The pinched throat is dealt with in his Master's thesis: "Modal sound propagation in curved horns of rectangular cross-section".
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Dr. Keele's study is a good reference for MTM crossover design. Can’t find Part 2...
https://www.xlrtechs.com/dbkeele.co...ear Phase Digital Crossover Flters Part 1.pdf
https://www.xlrtechs.com/dbkeele.co...ear Phase Digital Crossover Flters Part 1.pdf
https://oceanwayaudio.com/display/wp-content/uploads/2019/01/owa_hra_sheet_0119_LR.pdf
I’m assuming a good sounding implementation of ‘2-way’ MTM design with 2 15” woofers and a 1” HF Cd (assuming TAD200x) paired with a 100x40’ horn.
I’m assuming a good sounding implementation of ‘2-way’ MTM design with 2 15” woofers and a 1” HF Cd (assuming TAD200x) paired with a 100x40’ horn.
Seriously, this kind of large WTW is somewhat problematic in a room where the ceiling is untreated and/or low.
Great! 🙂
BTW, I was applying linear phase for WTW for years, but now, 18dB minimal phase. Different sounding approach, and I can't say which is better...
Not sure if posted yet, but this info about the JBL K2 project has same objectives as topic.
Some interesting info I found. 650hz crossover. 2nd order. Check the manuals of the various models
AllegroSound * JBL Project K2 S9500 *
Some interesting info I found. 650hz crossover. 2nd order. Check the manuals of the various models
AllegroSound * JBL Project K2 S9500 *