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2 ohms woofers is this the future for cabinets

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bass*en*mass View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bass*en*mass Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2017 at 4:29am
Originally posted by MarjanM MarjanM wrote:

I am yet to understand what is this driver advantage over a 18SW115.


way more linear xmax?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2017 at 10:52am
6mm more xmax for 3 times the money??? Eerrmmmm, no thanks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2017 at 7:37pm
Imagine phase plug for this
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ricci Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2017 at 10:04pm
The benefits of this type of driver are higher efficiency and longer xmax. In other words more output potential if used well. Combining both attributes in one driver is not easy. It is much easier to make a very efficient driver or a driver with a ton of stroke, but both in the same unit requires significant engineering to balance the tradeoffs and increased material costs. This seems to be the way much of the industry is heading. Companies want more output from less weight and size. It requires driver design to follow suit.
The main limitations in drivers are the thermal limits and the excursion limits. Higher efficiency allows the system to produce the same output level as a lower efficiency cab with less power being dissipated in the voice coil. Heating of the voice coil causes a loss of output or efficiency which is bad. Increasing the linear excursion allows greater output before output compression sets in, distortion gets objectionable, or before something limits in the suspension or motor geometry. Once the voice coil starts to leave the linear region of operation (exceeding xmax) the BL drops, distortion increases dramatically and the driver starts to compress the signal. This in turn causes even more heating in the voice coil as the air movement in the motor and the excursion of the diaphragm are no longer responding in a linear manner to signal increases. This is also bad.
 
Doubling driver displacement (excursion) results in a 6dB increase in output.
Doubling the amplifier power results in an increase of only 3dB of output.
 
All systems I've worked with measure and sound their worst when operating near their limits. Most will be compressing the output to some degree. 3dB of thermal compression would not be out of the ordinary when a subwoofer is being run hard over a long period of time. If you can do a driver swap to a more efficient driver with 25% more xmax it is possible that you'll gain back 1 or 2dB, lower distortion and retain better dynamic accuracy. A 2dB gain may not sound like much but it is when how much extra amplifier would be required to achieve it is considered. Sure you could build a bigger sub or multiple cabs to get the output but at some point that is no longer an option.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2017 at 10:29pm
What effectiveness are you talking in matter of horns?
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2017 at 2:13pm

In the pro audio world, we look at things differently. Having one 2 ohm nominal woofer is equivalent to having four 8 ohm nominal woofers. From a surface area, excursion, coupling effect in addition to SPL aspect, one could use four 18 inch drivers that will surpass the performance of the single 21 inch driver in question.

 

This speaker may be ideal for a small area where you need to extract every bit of SPL out of a single loudspeaker such as a vehicle or household. However in the Pro Audio world, when you start calculating how much money is going to be invested in acquiring the proper amount drivers to attain the correct coverage in addition to running your amplifiers ragged under a 2 ohm load, it is not worth it.

 

Honestly, if the TS Parameters does not tell you that you will need to rely heavily on equalisation in order to attain significant bass below 150 Hertz, the cost of operating multiples will.

 

Best Regards,



Edited by Elliot Thompson - 23 May 2017 at 3:12pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote djeddie Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2017 at 7:56pm
Originally posted by Elliot Thompson Elliot Thompson wrote:

...you will need to rely heavily on equalisation in order to attain significant bass below 150 Hertz...


Bose made a lot of money from that!

Sorry, couldn't resist!Big smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2017 at 10:59am
Originally posted by djeddie djeddie wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

...you will need to rely heavily on equalisation in order to attain significant bass below 150 Hertz...


Bose made a lot of money from that!

Sorry, couldn't resist!Big smile


Exactly!

Bose's methods were strong equalisation and lots of corner loading to achieve bass.

Home Audio guys can use corners in their homes to enhance the Bass. Pro Audio guys need to make sure the speaker can deliver it's performance with no additional boundaries other than the ground it resides on.

Best Regards,


Edited by Elliot Thompson - 24 May 2017 at 11:03am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ricci Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2017 at 5:48pm
Originally posted by Elliot Thompson Elliot Thompson wrote:

In the pro audio world, we look at things differently. Having one 2 ohm nominal woofer is equivalent to having four 8 ohm nominal woofers. From a surface area, excursion, coupling effect in addition to SPL aspect, one could use four 18 inch drivers that will surpass the performance of the single 21 inch driver in question.

Of course 4 good quality 18" drivers in 4X the enclosure volume and the multiple times the truck space and weight will outperform a single of any 18" no matter how strong.
 
The nominal impedance of the driver is irrelevant unless the user doesn't know what they are doing. Proper system design will get the load to the amplifier/s matched up well. If not that's not the driver or amplifiers fault.

Originally posted by Elliot Thompson Elliot Thompson wrote:

This speaker may be ideal for a small area where you need to extract every bit of SPL out of a single loudspeaker such as a vehicle or household. However in the Pro Audio world, when you start calculating how much money is going to be invested in acquiring the proper amount drivers to attain the correct coverage

 Exactly. However pro audio is also heading in the direction of attempting to extract more output and extension from less size and weight. It's not just home or car audio. This is accomplished through drivers with higher efficiency and more displacement capability + the thermal power handling to use it. Otherwise we'd still be using the drivers from 30 years ago, in huge cabinets, with 400w ratings and 5mm xmax. Moving 8 cabs that can perform on par with 12 of another while being 2/3rds the space and weight sounds good right? Unfortunately the side affect is increased up front cost for the hardware to do that. for some it will be worth it. For others it will not.  

Originally posted by Elliot Thompson Elliot Thompson wrote:

Honestly, if the TS Parameters does not tell you that you will need to rely heavily on equalisation in order to attain significant bass below 150 Hertz, the cost of operating multiples will.

 

Best Regards,

 
Equalization required is entirely dependent on the driver + cabinet system. There is no reason that these would require more than any other driver. It is possible to design cabinets that work with the drivers that would require very little. Also virtually all subwoofers are equalized these days. A simple low pass and high pass are technically equalization. Active (powered) subwoofers are pretty much universally heavily equalized, limited, etc.
 
Anyway that's just my take on why this type of driver is being developed and what the applications for it are. Maximum performance from minimum space. That certainly doesn't make sense for most applications but it does for some.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2017 at 6:22pm
Isn't a big part of the IPAL system that you can somewhat tweak the T/S parameters through the integration of te sensors etc to maintain a certain output?
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Post Options Post Options   Thanks (1) Thanks(1)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2017 at 6:33pm
The ts parameters clearly say "put me in enormous horn" Neither br nor any another enclosure type will fit. As I understand it amp module from Powersoft allows to tweak ts.
0 latency dsp + pressure sensor could change speaker the same way as .wav and vinyl disc.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2017 at 7:05pm
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