Usually, people listen at 75-80dB at most in their home at say 3-4 meters away. At 4 meters, that would mean the loudspeaker mean output is around 87-92dB/1m. There should be sufficient headroom for well over 100dB in the peaks at those output levels.
I would not be comfortable at over 90dB at my listening position for prolonged exposure.
I would not be comfortable at over 90dB at my listening position for prolonged exposure.
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Joined 2003
I'm assuming continuous means average, since no one listens to sine waves. 105dB average is a bit aggressive design goal IMO. For movies, dynamic range can be very high, so I would maybe focus more on peak SPL needs for that.
A good goal for home audio would be 85dB average at 3m, and consider about 12dB crest factor for music, so peaks of 97dB, or a max SPL goal of around 106.5dB@1m.
A good goal for home audio would be 85dB average at 3m, and consider about 12dB crest factor for music, so peaks of 97dB, or a max SPL goal of around 106.5dB@1m.
That’s full range. But even cutting out the bass at 100hz it can’t do much more according to some modelling I tried. The pure mid should do a bit better as the efficiency will be higher.
Continuous. Full Atmos design guide and specs here:
https://professional.dolby.com/siteassets/cinema-products---documents/dolby-atmos-specifications.pdf
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Joined 2003
"Each screen loudspeaker system and associated amplifiers must have a maximum output capability of 105 dB continuous sound pressure level (SPL) at the reference listening position (RLP)"
There's other words in there, reading on it says 105dB for the woofer, 101dB for midrange. I read that as max power requirements rather than strict SPL requirements, since words like "average" and "crest factor" aren't used which commonly describe audio signal. The words "maximum output" is key, in other words, the speaker should be capable of 105dB at the listening position, 0dB crest factor accounted for. For commercial design, continuous power handling for thermal design would be more geared towards making sure the speaker survive even if the teenager running the theatre operation does something stupid. Later on it suggests 3dB headroom on the amp, suggesting again that the SPL target is "maximum", allowing only for slight extra un-clipped signal.
In any case, design to whatever goal you want, if you want to hit theatre Dolby design spec then by all means go for it. 101dB @ 3m = 110.5dB@1m. Reaching that goal "continuously" demands a larger pro driver, you'll notice the Atmos document shows compression midrange and tweeters, only the woofers are normal cone drivers.
Have fun, and get some earplugs when you test that 105dB continuous capability
All depends on the size of the theatre. If a mid can output 117dB @ 1m, it’s enough for seating up to 4m away. Those specs in that PDF are for commercial theatres. But my clients want an even better experience than a commercial theatre. Which is why I’m using far better drivers and electronics than commercial theatres use. But I don’t want to sacrifice any dynamics or SPL capabilities.
The 4" SB A cac driver can play loud?
back to the BlieSMa mid...
I am trying to shoot for 1.2 X c-c spacing for the XO. I came up with the drivers 18mm apart and an XO at 3650hz for the t25 + m74.
I attached a comparison to my other 3way. They look so different and I wonder what I can hear.
I have not simulated anything in vcad yet. Waiting for better data to know where I can place what. (thanks x1,000,000 hificompass!) The baffle shape might be a triangle. Ah, it will be so nice to give zero ***** what is happening behind the baffle. No box. No stuffing. Ahhh.
back to the BlieSMa mid...
I am trying to shoot for 1.2 X c-c spacing for the XO. I came up with the drivers 18mm apart and an XO at 3650hz for the t25 + m74.
I attached a comparison to my other 3way. They look so different and I wonder what I can hear.
I have not simulated anything in vcad yet. Waiting for better data to know where I can place what. (thanks x1,000,000 hificompass!) The baffle shape might be a triangle. Ah, it will be so nice to give zero ***** what is happening behind the baffle. No box. No stuffing. Ahhh.
When it comes to cinema sound then it's hard to beat IMAX. They use high quality JBL drivers and sound is very nice.
When it comes to building multi-way it's impossible (as far as i know) to do it right without acoustic lenses of some sort. Without lens you always get unevenness at certain angle of axis.
When it comes to building multi-way it's impossible (as far as i know) to do it right without acoustic lenses of some sort. Without lens you always get unevenness at certain angle of axis.
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Heard back from Stan. He said the M74B can handle 115.4dB crossed over at 600hz with a 4th order. The T25B can only handle 112-113DB with a 4th order crossed over at 5k. Will need to go with the T34 for more SPL. In which it could easily do 118dB under the same conditions.
Regarding crossover point between the M74B and tweeter, he says it’s really room dependant. Depending on the reflections, room treatment used, placement etc. And it’s best to tune each speaker with DSP to the environment it’s in. Which is what I do anyways.
Regarding crossover point between the M74B and tweeter, he says it’s really room dependant. Depending on the reflections, room treatment used, placement etc. And it’s best to tune each speaker with DSP to the environment it’s in. Which is what I do anyways.
Hoping for near the pain threshold levels from drivers that are designed around the "near field" in a home and room which is often less than 20 square meters is maybe not the best.
While the BlieSMa drivers have a relative high sensitivity, they aren't close to the max SPL many professional drivers are capable of, and MTM/D'Appolito configuration comes to mind
as a way forward to increase the loudspeaker sensitivity and max SPL output. So you have options and the M74B is not the only driver you can consider.
While the BlieSMa drivers have a relative high sensitivity, they aren't close to the max SPL many professional drivers are capable of, and MTM/D'Appolito configuration comes to mind
as a way forward to increase the loudspeaker sensitivity and max SPL output. So you have options and the M74B is not the only driver you can consider.
Why not consider borrowing from HHH and the Calpamos loudspeaker ? The FaitalPro compression driver has a rated sens of 108dB and a horn should bring that to about 112dB.
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Calpamos.pdf
FaitalPRO | HF Drivers | HF201 (8Ω)
Calpamos - "Detour Ahead" - Eliane Elias - YouTube
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Calpamos.pdf
FaitalPRO | HF Drivers | HF201 (8Ω)
Calpamos - "Detour Ahead" - Eliane Elias - YouTube
To quote an earlier entry: 380Euro for the Silk/Paper/Aluminium and 650Euro for the Beryllium (each). - That is a tough pill to swallow. I know of other drivers like the S.S Illuminator/Revelator as well as SBA CAC/Satori which can outperform the M74.
The T34/25B drivers are a no brainer for sure but unless one is 100% comfortable with the "limitations" of the M74 series and really REALLY know how to design loudspeakers, going for a multi speaker solutions and equally many M74B drivers which will
cost many thousands, looking at other options is not a bad idea
There is nothing wrong with the M74, any of them, as far as we know. The only thing to keep in mind, besides Accuton, these are among the most expensive midrange drivers out there. Value propitiation is poor compared to the competition, it just is.
But I am sure they sound lovely. This is the price one has to pay for the "best", and I dare not think about the rest of the loudspeaker, it too has to be on the same level so to speak.
The T34/25B drivers are a no brainer for sure but unless one is 100% comfortable with the "limitations" of the M74 series and really REALLY know how to design loudspeakers, going for a multi speaker solutions and equally many M74B drivers which will
cost many thousands, looking at other options is not a bad idea
There is nothing wrong with the M74, any of them, as far as we know. The only thing to keep in mind, besides Accuton, these are among the most expensive midrange drivers out there. Value propitiation is poor compared to the competition, it just is.
But I am sure they sound lovely. This is the price one has to pay for the "best", and I dare not think about the rest of the loudspeaker, it too has to be on the same level so to speak.
The Radian Beryllium compression drivers even cost more.
Radian 760NEOBePB High Frequency Beryllium Diaphragm Compression Drivers - Radian 760NEOBePB - Radian 760NEOBePB uses a lightweight neodymium magnet with a beryllium diaphragm. The Radian 760NEOBePB 2" high frequency compression driver that handles 1
If you want to go high end you need to open the wallet.
Radian 760NEOBePB High Frequency Beryllium Diaphragm Compression Drivers - Radian 760NEOBePB - Radian 760NEOBePB uses a lightweight neodymium magnet with a beryllium diaphragm. The Radian 760NEOBePB 2" high frequency compression driver that handles 1
If you want to go high end you need to open the wallet.
Correct to a certain degree
. The performance of drivers with the exception of Accuton which is more bragging stuff than anything else, is reflected in execution (not merely different) and measurements. The closer to the ideal the driver need to be, the costlier.But there are exceptions like the T25B-6 which for the €250/piece can be considered to be among the best dome tweeter in the world without one needing to sell a kidney or a leg. Expensive but doable.
Out of curiosity, which woofers do you intend to pair the T25/M74 with ?
You would need to hear them before saying a cone driver is on par or better. High end dome mids aren’t comparable to cones. There’s more than just a frequency response curve to how something sounds.
My main woofers will be the new 8” Purifi’s when released. And for subs the BMS 12’s and 15’s.
My main woofers will be the new 8” Purifi’s when released. And for subs the BMS 12’s and 15’s.