BP1Fanatic gave the short answer
You are missing that voltage, not watts are "fed" to the driver.
The EIA RS-426 "Power Rating" used by Eminence (and most driver manufacturers) is actually a pink noise band limited signal with an RMS voltage applied to the driver in free air based on the nominal impedance, 6 ohms for the LAB12, so "400 watts" is 49 volts RMS.
"Music Program" is twice that "Power", "800 watts", or 49 X 1.41/6.
That said, the free-air impedance of the driver is well above it's nominal impedance for much of the test signal's limited range, so it is not drawing the rated "power".
The impedance at any frequency determines the power in watts the driver draws from that voltage.
The impedance in the PAL12 box is near the DC resistance of the driver (4.29 ohms for the Lab 12, 3.11 for the LAB12, 5.4 for the BMS12S305, etc.) at Fb, the excursion minima, the frequency the driver draws the most power, and also is subjected to the most pressure.
At the excursion peaks above Fb where the excursion is highest, the impedance of the driver rises to many times it's DCR, drawing far less power, similar to the EIA RS-426 free air test.
At any rate, the BMS12S305 voice coil can survive more voltage/power than the LAB12.
Whether the BMS12S305 lighter carbon fiber cone can hold up to as much pressure without deformation (permanent or temporary) as the LAB12's heavier paper pulp cone is a different question.
If the cones were designed in the same way, I'd bet the BMS would be as stiff as a heavier paper pulp cone.
The LAB12 has a large inverted dust cap located roughly midway between the voice coil former and the surround, so has less unsupported span length than a typical cone, so may be stiffer.
Looking forward to hearing how your BMS12S305 performs in the PAL12.
Art
Thanks Art, certainly i will do , thing is the1st prototype will be very relative as i will not have a LAB12 loaded PAL12 cab to compare , at least by ear
but anyway, i guess a Geman made driver at the price of the china skars is no brainer.
wait till i want to make some more!! regular BMS price is 330, and i guess i will be stick with them cause i dont want to have PAL12 cabinets with drivers tuti fruti 😎
Btw, LAB12 BL=15 12S305 BL=20 so if the LAB survive the compression ratio of the PAL12, in theory the BMS can do it with ease right ?
the higher the BL , the more compression ratio a driver can withstand?
but anyway, i guess a Geman made driver at the price of the china skars is no brainer.
wait till i want to make some more!! regular BMS price is 330
, and i guess i will be stick with them cause i dont want to have PAL12 cabinets with drivers tuti fruti 😎Btw, LAB12 BL=15 12S305 BL=20 so if the LAB survive the compression ratio of the PAL12, in theory the BMS can do it with ease right ?
the higher the BL , the more compression ratio a driver can withstand?
Bigger the motor, higher the force the driver is able to push/pull the cone, but the cone needs to resist the force. It's very hard from user to know if motor strength and cone stiffness are well balanced, in general they aren't, so collecting experience is the way to go if you can't buy many parts to test.
In addition, when you reinforce the cone the driver sensibility is reduced so you need to think about another trade off. It worth to consider also distortion and driver life before replacement. Think too much and you go crazy
Ready this experience from laxandredeyed
He exaggerate the compression ratio for one of his design, so when he was playing a guitar note that stimulates the box resonances he ended up with unwanted noises, cone deformation, because it couldn't handle the involved forces. There are more to read and learn there.
https://www.diyaudio.com/community/...ild-loose-panel-or-some-other-problem.406237/
He exaggerate the compression ratio for one of his design, so when he was playing a guitar note that stimulates the box resonances he ended up with unwanted noises, cone deformation, because it couldn't handle the involved forces. There are more to read and learn there.
https://www.diyaudio.com/community/...ild-loose-panel-or-some-other-problem.406237/
Hey Guys,
i modeled this PRV driver in to the PAL12, look how it behave good @300 watts (10mm xmax)
LAB12 is shown in black,
is it desirable to have a flat freq response ? cause it models just flat with no EQ
although you loose around 3.5db on the LAB12 lobes
i am asking cause once i get one of the drivers, the next ones will be the same so to have matched cabinets
i am holding the BMS cause i can get just one at 50%, normal price is 330 for the BMS,
the PRV is 199 and the LAB12 is 260
so for me the PRV is the budget winner
what you guys think
i modeled this PRV driver in to the PAL12, look how it behave good @300 watts (10mm xmax)
LAB12 is shown in black,
is it desirable to have a flat freq response ? cause it models just flat with no EQ
although you loose around 3.5db on the LAB12 lobes
i am asking cause once i get one of the drivers, the next ones will be the same so to have matched cabinets
i am holding the BMS cause i can get just one at 50%, normal price is 330 for the BMS,
the PRV is 199 and the LAB12 is 260
so for me the PRV is the budget winner
what you guys think
Since horn response is exaggerating the peaks (lossless/perfect maths) then is it safe to assume a flat/damped simmed response is actually a bit overdamped and you might want a slightly bigger box volume or similar size/tuning adjustment to ’match’ up with the drivers Vas and Qts,Fs, moving mass…. that creates the freq response shapes(especially at resonances)?
What’s the lab12 measured freq response look like (pic from the thread attached to this at the beginning I think) as compared to the simmed ? Then what assumptions can be made about other simulated results from that?
What’s the lab12 measured freq response look like (pic from the thread attached to this at the beginning I think) as compared to the simmed ? Then what assumptions can be made about other simulated results from that?
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post#40 have the HR screen
https://www.diyaudio.com/community/...d-pa-tapped-horn-35hz-extension.232219/page-2
mine is the same... except for some thiele small LAB12 discrepancies , i copied mine from the eminence page
but they are a little different from the original post
more below I simmed the PRV 12W1600, it have 4" Voice Coil and 22.5 BL
Hey bogger
so does the PRV looks ok for the PAL12 ?
PRV 12W1600
https://www.diyaudio.com/community/...d-pa-tapped-horn-35hz-extension.232219/page-2
mine is the same... except for some thiele small LAB12 discrepancies , i copied mine from the eminence page
but they are a little different from the original post
more below I simmed the PRV 12W1600, it have 4" Voice Coil and 22.5 BL
Hey bogger
so does the PRV looks ok for the PAL12 ?
PRV 12W1600
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ok this is the right thiele small paramaters for the 12W1600
despite the fact of the high FS of 51.22
it models like this on the PAL12 HR screen
but.... on a 125L BR box it can take 100 more watts for a total of 400 to reach xmax
but still is around 3-4dB less SPL that the PAL12 cabinet (using the same 12W1600 driver)
interesting.
that means we can get 3-4 dB more from this driver on the TH cabinet than on a vented box
is that the same for all type of drivers ? ( i am discovering the wheel !! ) 😁
despite the fact of the high FS of 51.22
it models like this on the PAL12 HR screen
but.... on a 125L BR box it can take 100 more watts for a total of 400 to reach xmax
but still is around 3-4dB less SPL that the PAL12 cabinet (using the same 12W1600 driver)
interesting.
that means we can get 3-4 dB more from this driver on the TH cabinet than on a vented box
is that the same for all type of drivers ? ( i am discovering the wheel !! ) 😁
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So I think you are saying the 12W1600 in the BR box requires more voltage to reach Xmax in the 125L box?
If so, it may lose more SPL in the BR due to thermal compression.
If the BR ports are not large enough, it may also have more loss due to "port compression".
What I considered a "large" port in 2011 I'd consider "marginal", or "undersized" now.
https://www.diyaudio.com/community/threads/tapped-horn-vs-bass-reflex-case-study.184992/
The PAL 12 TH is ~280 liter gross volume, you are comparing it to a 125L (net?) BR.
Depending on the bass reflex port volume, real world averaged difference in actual output of 4-6dB when driven to Xmax seems reasonable.
That said, I would not depend on comparison accuracy when simulating different manufacturer's drivers without verification of each driver's actual Xmax.
It's called EFFICIENCY!
The TH has more dB per voltage than the BR enclosure even though they both only need 7 pieces of wood to create an enclosure in their simplest forms.
How big is the TH?
Try a negative flare tapped horn. See if you can get to the same 125L as the BR and see if the T-TQWT can match or out perform the BR. If it matches, then you got built in speaker protection (no grill).
Hey but doesn't suppose that long ports make looses ?
also, parallel walls make resonances ?
that's why TH have angled walls ?