Out of interest, I decided to check for sure
.On the attached chart,
The blue trace shows the response when segment 4 is assumed to have a tapering parabolic flare with a throat area of 1341.93 cm^2, a mouth area of 360 cm^2 and a length of 73.66 cm.
The red trace shows the response when segment 4 is assumed to be cylindrical, with a constant cross-sectional area of 1341.93 cm^2 and a length of 73.66 cm, with a step constriction at the mouth reducing the area to 360 cm^2.
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It could certainly be made if the cabinet design was modified to more accurately match the simulation model * (it would require some panels to be non-parallel), but as Booger weldz and BP1Fanatic have pointed out, horn mouth particle velocity could become an issue at the higher SPL levels.
* As it turns out, using a parabolic approximation for the final segment seems to give a reasonably useful prediction of performance anyway
.The difference is 3.5% at 100 Hz, which is not too bad I would have thought, considering the approximation being made with segment 4.
I'm looking at the dB differences. 3dB is the equivalent of doubling amplifier power into the system, and a broad 3dB difference in efficiency across the passband will definitely be noticeable. Considering that the graph vertical scale is in 20 dB steps, I'm seeing differences of more than 3dB in the graph you shared.
In the attached chart the level of the red trace has been reduced by 4.57 dB so that at 100 Hz the SPL's of the two traces are exactly the same (126.15 dB). Not sure about there being a rising response difference at 80 Hz, but there is certainly a difference in bass extension at lower frequencies.
The good news is that using a parabolic approximation for segment 4 would mean that above 37 Hz the measured SPL would be higher than predicted. The not-so-good news is that using a parabolic approximation for segment 4 would mean that the actual bass extension would be less than predicted.
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He published the screenshot from the sketch of model TL3.
To see the driver placement you can go to the website or check the 3D model.
https://freeloudspeakerplan.rf.gd
You can make the H4 with the same CSA of H1 and H2 or different one, the user has the freedom to adjust. The driver is placed ~1/3 of the total horn length.
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Ok, i lowered the input per driver to 500 watts, thats 1kw per cabinet
so my XMAX do not get crazy
now i need 6 of those to hit 140
the bump do not really look too bad and HR emphasize the peaks and dips, that means in real life the low bump will be lower or non existen
and in any case you can do Subtractive EQ, that per the book is much better than additive EQ
i know that is best to CUT than to BOOST ( at least you dont use more power but less )
how the graph looks now 6 cabs , 1Kw each cab, those DDX12's can take 1.5Kw each, now i will only feed them 1/3 of that
substract the duty cycles and in will be much less sustained taking account the crest factor
so, in theory i will have Cold Coils. and you can go past past 20% Xmax , but im not, im within spec.
What i am learning is that when doing simulations you are limited either by XMAX or By Power,
in this case, i am limited by XMAX cause i am hitting it with 500W only , but the driver can take 1.5Kw
and from 206L i growed the cabinet to 420L so i can hit 30Hz Flat
IronLaw just punched me in the face, there is no free lunch. strange thing is that reading theory is one thing, but when you
start doing the sims by yourself there is a satisfaction feeling that puts a smile on your face.
does an ideal cabinet design will let you hit both at the same time, XMAX and POWER so that way you maximize
what the driver can deliver.
does that exist ? or is just a wet dream
what i wish is that like there was a chatGPT like but for cabinet design, you tell the AI, use this XYZ driver and maximize for power and Xmax
or Maximize for lower extension or maximize for SPL and so on, the combinations are endeless.
The AI will have the database of all known cabinets known to man until now and all the drivers currently made
plus (he/she) can extrapolate and come up with some new or hybrid designs that are not being made yet by man.
Ohh my! it is time for 2 XANAX!!
in this case, i am limited by XMAX cause i am hitting it with 500W only , but the driver can take 1.5Kw
and from 206L i growed the cabinet to 420L so i can hit 30Hz Flat
IronLaw just punched me in the face, there is no free lunch. strange thing is that reading theory is one thing, but when you
start doing the sims by yourself there is a satisfaction feeling that puts a smile on your face.
does an ideal cabinet design will let you hit both at the same time, XMAX and POWER so that way you maximize
what the driver can deliver.
does that exist ? or is just a wet dream
what i wish is that like there was a chatGPT like but for cabinet design, you tell the AI, use this XYZ driver and maximize for power and Xmax
or Maximize for lower extension or maximize for SPL and so on, the combinations are endeless.
The AI will have the database of all known cabinets known to man until now and all the drivers currently made
plus (he/she) can extrapolate and come up with some new or hybrid designs that are not being made yet by man.
Ohh my! it is time for 2 XANAX!!
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on my quest of hitting 140 in the most budget way possible.
the CRAM i think is not optimal
6 cabs are 12 drivers, that means 150 bucks times 12, that means 1800 plus tax is 1,950 bucks
add the wood of 6 cabinets, at least 2 8x4 sheets of ply per cab , that is 12 sheets of 3/4 ply at 60 a piece is 780 with tax
so thats 2780 rounding number.... add the duratex and connectors and stuff, so we are looking at around 3000 to 3200
So Guys,
how i can hit 140 @30Hz with the least amount of money
any drivers like quad 8's or anything and any cab design no matter if its harder to build
thing is that i want to hit the most SPL per buck @30Hz