Thank you very much for that. Now I get it.
I'm probably going to end up with OSB board inner/Ply outer for double thickness since these are so big. I'll probably limit the front baffle to 24" (making the inner width 21") so I can get a front and back panel from a single sheet of ply. While I want everything to be "perfect" I think getting most of the way there should be good enough.
GM (or anyone), do you have a magic decoder ring or link or site that explains the terms in the notepad file you posted for the JBL2220H BIB? I've stared at it and stared at it and while I'm familiar with many speaker parameter terms (Qts, Vas, Fs, etc.) these have me baffled.
I was also looking at the site for the "New Qts with series resistor". This speaker is going to have a crossover to the horn compression driver tweeter. Do the parts in the low pass filter on the woofer count as part of this series resistance?
I'd like to not just build something but actually understand it.
I was also looking at the site for the "New Qts with series resistor". This speaker is going to have a crossover to the horn compression driver tweeter. Do the parts in the low pass filter on the woofer count as part of this series resistance?
I'd like to not just build something but actually understand it.
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The ones specific to HR are in its HELP File.
Thiele Small parameters equations - How each one affects the others
If really serious about learning, then download Small's and Thiele's AES articles: Read Research - Articles
Qts' = Qts + any added series resistance: mh-audio.nl - Home
ALL resistance in series with the voice coil [VC] ideally needs to be accounted for when coupling to a high output impedance.
GM
Hi Freddi, thanks for posting those. If they're modeling the huge BIB's that I'm going to build I would have thought they'd have lower bass response.
Is Pi space as follows?
1 Pi = out in the room away from room boundaries
2 Pi = against the wall
4 Pi = in a corner
Or is it the other way 'round?
Never mind, found it in the Horn Response tutorial.
.5 or 1/8 space is corner loading
1 or 1/4 space is floor and wall
2 or 1/2 space is in a room away from the walls
4 or full space is... well, hanging in space.
I guess mine is going to be .75 or 1/6 space - floor, wall and ceiling kinda close to a corner.
.5 or 1/8 space is corner loading
1 or 1/4 space is floor and wall
2 or 1/2 space is in a room away from the walls
4 or full space is... well, hanging in space.
I guess mine is going to be .75 or 1/6 space - floor, wall and ceiling kinda close to a corner.
I'd be surprised if it didn't.
The higher the output impedance [Rs], the greater the perceived overall bass output since it more closely tracks the speaker's impedance with the trade-off being an increasingly more uneven response with increasing [Rs] and why the pioneers spec'd impedance matching amps with variable damping [DF] tone controls with as much as 2x more [Rs] than the amp's base, which in turn had the trade-off of being some pretty 'sloppy'/'flabby'/'loose' bass unless tuned somewhat below the recording's peak bass output, leaving the 'bass' to basically mean the mid-bass on most recordings up to circa the early '70s.
In short, a higher output impedance..........
GM
I guess mine is going to be .75 or 1/6 space - floor, wall and ceiling kinda close to a corner.
Need to keep in mind that HR's boundary loading sims are optimistic unless literally in a large enough open field and/or underground concrete bunker, etc., so for bass, 2pi is more realistic for a single corner loading to ~match up with my stick built, drywall sheathed, 'floating' floor construction. :(
GM
that's a 1950's University Sound Classic front loaded horn by Abraham Cohen and Saul White. It takes a lot of wood too and should be bigger and badder if not a long path back loaded pipehorn I'd have to read on how to sim a BIB in hornresp. (GM -how does that go?) It was quick in AJhorn. 2220H had some cone cry to may ears if driven up too high but that was on a straight midbass horn. Maybe its curvilinear cone contributed (?)
In a corner with 2220H, 1 watt sensitivity for the old University Classic would be described as ~"113dB" with a LF corner (-3dB) of around 50Hz - - that ain't too shabby. About 30 years ago I
ran 2220H in my klipshcorns - made mids a big snappier but gave up lots of LF output due to 2200's small xmax
compared to the cheap but high xmax K33. If I had understood at the time, I would have reduced the K-horn's back chamber to both flatten
response and reduce cone excursion below cutoff.
Classic's back chamber volume is around 80 liters - for this sim I reduced that to 35 liters
The old Karlson would be a reasonable housing for a 2220.
I'd have to read on how to sim a BIB in hornresp. (GM -how does that go?) It was quick in AJhorn. 2220H had some cone cry to may ears if driven up too high but that was on a straight midbass horn. Maybe its curvilinear cone contributed (?)In a corner with 2220H, 1 watt sensitivity for the old University Classic would be described as ~"113dB" with a LF corner (-3dB) of around 50Hz - - that ain't too shabby. About 30 years ago I
ran 2220H in my klipshcorns - made mids a big snappier but gave up lots of LF output due to 2200's small xmax
compared to the cheap but high xmax K33. If I had understood at the time, I would have reduced the K-horn's back chamber to both flatten
response and reduce cone excursion below cutoff.
Classic's back chamber volume is around 80 liters - for this sim I reduced that to 35 liters
The old Karlson would be a reasonable housing for a 2220.
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Mine's a 2220A, the earlier alnico version. The low pass crosses over at 900Hz I believe because of the rising response. I think the horn is crossed at 3K. It's a version of the high efficiency Econowave speaker tweaked for these specific drivers by Zilch (RIP)
I'm not likely to crank it too loud with two watts on tap (or more with my Heathkits).
had some of those - never used them - traded them for little K cabinets (never received) so gave them away and paid $$$ shipping 2000 miles plus wood template for straight 40Hz horn
maybe GM will cook up a BIB for yours and that 45 amp. I don't have a spreadsheet program nor familiar with them. Does the BIB calculator work from T-S ?
I would relegate 2220 to relatively small midbass cabinets then add potent tapped horn/pipe subwoofer(s) to handle the low octaves -but I can co-exist with
cheap SS amps
maybe GM will cook up a BIB for yours and that 45 amp. I don't have a spreadsheet program nor familiar with them. Does the BIB calculator work from T-S ?
I would relegate 2220 to relatively small midbass cabinets then add potent tapped horn/pipe subwoofer(s) to handle the low octaves -but I can co-exist with
cheap SS amps
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had some of those - never used them - traded them for little K cabinets (never received) so gave them away and paid $$$ shipping 2000 miles plus wood template for straight 40Hz horn
maybe GM will cook up a BIB for yours and that 45 amp. I don't have a spreadsheet program nor familiar with them. Does the BIB calculator work from T-S ?
I would relegate 2220 to relatively small midbass cabinets then add potent tapped horn/pipe subwoofer(s) to handle the low octaves -but I can co-exist with
cheap SS amps
I currently have a pair of Sachiko's with FE206ES-R drivers in them and have used them for several years. They're about 98-99 db 1W/1M efficient and I love them but they don't do low bass. I figured I'd give a mongo huge BIB a try since my wife has said she'd love it if I built a pair of speakers with deeper and better bass. I have the BIB calculator but GM has said that with high output impedance amplifiers it may be a good idea to oversize the cabinet a bit. I've kinda decided on how big they will be just based on budgetary constraints. I may change my mind but for now I'm debating whether to build a test cabinet out of OSB or to jump in whole hog and just build them properly.
I posted the 2220H HR file earlier in the thread, which for box design is the same for the 2220A*, so DL/install it: https://www.diyaudio.com/forums/att...043-bigger-bigger-badder-bib-jbl2220h_bib-txt
* per these specs: http://www.jblproservice.com/pdf/thiele small parameters/theile parameters.pdf
Yes, it just uses Fs, Vas, Qts' = Qts + any added series resistance [Rs]: mh-audio.nl - Home
Rev. BIB Excel SS: https://www.diyaudio.com/forums/att...5-begins-fostex-fe166en-bib-bib_166_gm_v2-zip
Godzilla BIB site w/ V1 & 2 Excel SS: BIB Calculator | Speaker Projects by Zilla
Godzilla BIB site w/ BIB layout, pictures: BIB Pictures | Speaker Projects by Zilla
Don't recall at this late date what is different between the V1, V2 SS nor why he even lists it.
GM
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