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Audio Discussions
Topic: A buddy did incl research why

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Posted by Romy the Cat on 06-22-2017
The last month during the Munich show some folks from Ascendo Audio 50" showed a new 50” subwoofer.  
 
https://www.youtube.com/watch?v=jIyUmpz9dII
 

I am not wild about what I saw, it was WAY undersized enclosure for the displaced volume and this should sound horribly controlled, compressed and homogenized.  Most likely the will put in there some kind of active feedback with pumping in a huge amount of power, the solution that has zillion own problems. I was told about 78” subwoofer made and I am sure it is not the last size out there.  
 
I did not hear the subwoofers above, not that I have interest. As I have a very low expectations. The biggest woofers I head was right here a Boston the fellow I know has a pair of EV 30” subwoofers working together. The sound he has in bass is horrible. I do not blain in his bad bass the EV woofers. The quality of bass is contingent upon so many reason and it would not be smart to blain just the drivers. Still, the preoccupation with the larger driver size makes me a bit puzzle.  
 
So, if we have a huge woofer vs an equivalent of the same surface of the small woofers then what solution would be preferable? I naturally a bit afraid of the very large woofer. The biggest I had was a pair of 24” Fane, which was not good and here is my experience with large drivers is over. I personally did not see any more of less expensive or good motors made for more than 18” drivers. Still, if would be VERY interesting if somebody make the identical motors for let say 24” driver and the equivalent let say 10” drivers and to compare the result.

Posted by martinshorn on 06-22-2017
hi Romy

A friend of mine tested it and found that he likes the faster dryer response. His colleague used many big PAs, while he had about 20 times 8 inchers. He first assumed must be the mass, but in lows its not sooo relevant. 

The computer simulations even promised similar results in terms of efficiency, distortion, energy consumption etc etc comparing 10x8" to one 21" with slightly more xmax. 

In his last try he found some hints. 

He took several different sizes in the smalles possible enclosure they could fit, ran 50hz sinus with 5mm xmax and installed an xcursion laser sensor on it. Interesting that the big drivers (eg 15") had significant variations of measured xcursion in different positions of the membrane. Biggest difference between coil/dustcap pos and near surround. Conclusion was that despite the low frequency (multiple octaves below the braking point) starts bending. And so not following the coil/input precisely. 

In free air due to less compression the effect is harder to measure, but that's the standard unfortunately. He found the smaller the better. He prefers 8" with paper, but found 10" with very rigid membranes being the max size possible that was not bending yet. 

Cheers Josh 

Posted by Scott L on 01-20-2018
 Romy the Cat wrote:
The last month during the Munich show some folks from Ascendo Audio 50" showed a new 50” subwoofer.  
 
https://www.youtube.com/watch?v=jIyUmpz9dII
 

I am not wild about what I saw, it was WAY undersized enclosure for the displaced volume and this should sound horribly controlled, compressed and homogenized.  Most likely the will put in there some kind of active feedback with pumping in a huge amount of power, the solution that has zillion own problems. I was told about 78” subwoofer made and I am sure it is not the last size out there.  
 
I did not hear the subwoofers above, not that I have interest. As I have a very low expectations. The biggest woofers I head was right here a Boston the fellow I know has a pair of EV 30” subwoofers working together. The sound he has in bass is horrible. I do not blain in his bad bass the EV woofers. The quality of bass is contingent upon so many reason and it would not be smart to blain just the drivers. Still, the preoccupation with the larger driver size makes me a bit puzzle.  
 
So, if we have a huge woofer vs an equivalent of the same surface of the small woofers then what solution would be preferable? I naturally a bit afraid of the very large woofer. The biggest I had was a pair of 24” Fane, which was not good and here is my experience with large drivers is over. I personally did not see any more of less expensive or good motors made for more than 18” drivers. Still, if would be VERY interesting if somebody make the identical motors for let say 24” driver and the equivalent let say 10” drivers and to compare the result.


Generally speaking, the advantage of a larger membrane woofer driver will be it's inherent lower free air resonance, but only up to a point. A 15 inch frame, for all intents and purposes is large enough. There exists a complex relationship between cone strength, mass and flux density which all play part in the mix. Those stupid things called car audio subwoofers should be avoided at all costs. Depending upon what the designer (and/or/end user) is wishing to accomplish, multiples 10 inch drivers could also be effective. Multiple 15's, even. Even after all these years, Hoffman's Iron Law still prevails. Silliness in speaker design attempts, however, have grown exponentially.

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