Thank you for the clarification!
A bit off topic with that discussion, but maybe someone can lend some advice or experience. I’ve been back and forth with the idea of buying the M74B or M142A for a 3-way, high quality speaker system. No PA SPL levels, just home listening.
The M74B exhibits an off-axis response that may pair well with my tweeters of choice (RAAL 140-15DAM), however, I’m uncertain if this mid’s distortion/fundamental resonance would pose a problem if it were crossed to the woofer at 500Hz. The M142A can be crossed lower and seems to have low distortion. I wonder if this midrange is suited for this use case?
A bit off topic with that discussion, but maybe someone can lend some advice or experience. I’ve been back and forth with the idea of buying the M74B or M142A for a 3-way, high quality speaker system. No PA SPL levels, just home listening.
The M74B exhibits an off-axis response that may pair well with my tweeters of choice (RAAL 140-15DAM), however, I’m uncertain if this mid’s distortion/fundamental resonance would pose a problem if it were crossed to the woofer at 500Hz. The M142A can be crossed lower and seems to have low distortion. I wonder if this midrange is suited for this use case?
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Yes! I had one batch significant different to the others. It's for sure not a high end driver with the concistency you need.
But when you get good ones ... they are really good and more broadband as other 2".
Thats's EXACTLY my thoughts about these ATC and PMC speakers. The midrange is really good. But these tweeters ...
I also don't like the lf of the PMCs in medium/smaller rooms, gets boomy very quickly. But I'm used to closed speakers which are EQed for the room.
@kouiky
M74B is very low THD and capable of very high SPL. 500Hz crossover is fine. The bigger ones can be crossed over lower but don't go louder or have less THD in the midrange. And can't go as high obviously.
So depending on your lf drivers the 3" are still the best solution in my opinion. But when combining with 2 15" for e.g. I would chose the big crazy domes.
There is always Accuton C90, and now also BD90. Just a shame it's an inverted dome... and will cost same as a nice car.
https://accuton.com/products/drivers/diamond/BD90-6-727
https://accuton.com/products/drivers/diamond/BD90-6-727
I don't like the accutons at all. They sound very volume dependant IOW change sound signature as volume varies.
I talked with an engineer who worked for Thiele about this. He said the issue lye within the cone material and surroun termination. These ceramic drivers are not dampened a well as other drivers with stiffer membranes and are subject to some eigenmodes which don't show up in laser interferometry analysis. The ceramic behaves like glass in some ways, which has some elasticity properties as a fluid and also a polymeric solid. The response to vibrational amplitude isn't linear. It depends on the crystallized structure of the way the ceramic is produced. Its not a very predictable material to make a driver diaphragm out of. I personally don't like the "brittle" sound they produce when the output levels go up.
I also found out the hard way most Thiele/Accuton mids are rather fragile. I had a set of the older 4" concave mids sent to me by a customer for evaluation and crossover development. They didn't match very well as a pair and also had a significant amount of VC treble bleed from the side of the VC former which is a sign of an underdampened former. This is a specific test I use to determine whether a driver is well behaved for operation as a wide banded mid above its diameter specific breakup mode. Some other larger cone mids like the Audax PR170MO can be run into their softer, wide banded breakup area without much problem - some people prefer the sound of this, as it developes a wide and euphonic sound stage. Most Accuton mids can't be run this way due to several issues they have ie. narrow banded breakup at multiple frequencies and at varying off axis angles.
These ceramic cone drivers are only suitable for operation well outside of their breakup modes and even then still exhibit signs of IMD related HD artifacts in their main passband. A good paper cone will always sound better in most cases, as do some polymer and composite materials like Rohacell, Graphene and glass fiber.
I talked with an engineer who worked for Thiele about this. He said the issue lye within the cone material and surroun termination. These ceramic drivers are not dampened a well as other drivers with stiffer membranes and are subject to some eigenmodes which don't show up in laser interferometry analysis. The ceramic behaves like glass in some ways, which has some elasticity properties as a fluid and also a polymeric solid. The response to vibrational amplitude isn't linear. It depends on the crystallized structure of the way the ceramic is produced. Its not a very predictable material to make a driver diaphragm out of. I personally don't like the "brittle" sound they produce when the output levels go up.
I also found out the hard way most Thiele/Accuton mids are rather fragile. I had a set of the older 4" concave mids sent to me by a customer for evaluation and crossover development. They didn't match very well as a pair and also had a significant amount of VC treble bleed from the side of the VC former which is a sign of an underdampened former. This is a specific test I use to determine whether a driver is well behaved for operation as a wide banded mid above its diameter specific breakup mode. Some other larger cone mids like the Audax PR170MO can be run into their softer, wide banded breakup area without much problem - some people prefer the sound of this, as it developes a wide and euphonic sound stage. Most Accuton mids can't be run this way due to several issues they have ie. narrow banded breakup at multiple frequencies and at varying off axis angles.
These ceramic cone drivers are only suitable for operation well outside of their breakup modes and even then still exhibit signs of IMD related HD artifacts in their main passband. A good paper cone will always sound better in most cases, as do some polymer and composite materials like Rohacell, Graphene and glass fiber.
Siare HM500 : Has a long coil probably one layer , I found at least one picture online where the former looks like treated paper! But that's no guarantee it has an aluminium coil carrier!
Buy one dome mid , open up and check for yourself!
Life is a long hard road full of surprises ... but don't give up!
we are harder
Buy one dome mid , open up and check for yourself!
Life is a long hard road full of surprises ... but don't give up!
we are harder
The problem you'll have is the secondary resonance from the air cavity behind the VC gap, which can't practically be changed or improved enough to eliminate or even partially to dampen the secondary peak. The chamber wasn't aluminum on the examples I checked. It appears to be dye cast zinc of sorts. The consistency of this driver is less than expected and unfortunately shows an unacceptable lack of precision, even at the price point its being sold.
I've had 6 pieces of Tang Band 75-1558SE on the shelf going completely unappreciated. Today I took some measurements in order to ensure they work well before selling. So here is a double-whammy.
1. I am selling 6 of these lovely 3" midrange domes
2. Here are some measurements for your appraisal. 2.83V @ 20cm in a 45cm x 20cm test baffle.
I'm unsure if some of the 2nd harmonic might be from my Beyer MM1 mic. I switched to a Dayton EMM-6 and the 2nd harmonic increased.
1. I am selling 6 of these lovely 3" midrange domes
2. Here are some measurements for your appraisal. 2.83V @ 20cm in a 45cm x 20cm test baffle.
I'm unsure if some of the 2nd harmonic might be from my Beyer MM1 mic. I switched to a Dayton EMM-6 and the 2nd harmonic increased.