optimum wattage in subs

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   I am talking about power compression.

Beyma, EighteenSound in addition to JBL offers power compression figures on their 18 inch woofers.  

Best Regards,  

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Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 27 March 2015 at 11:40pm
	I am talking about power compression. Beyma, EighteenSound in addition to JBL offers power compression figures on their 18 inch woofers. Best Regards,
	Elliot Thompson

70,s hero Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 14 December 2014 Location: bristol Status: Offline Points: 637	Post Options Post Reply Quote 70,s hero Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 10:12am
	I am looking at speaker drivers in isolation, I realize that cabinet design plays an important part but that is only the half of it. Edited by 70,s hero - 28 March 2015 at 10:16am
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70,s hero Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 14 December 2014 Location: bristol Status: Offline Points: 637	Post Options Post Reply Quote 70,s hero Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 10:33am
	Optimum wattage for less distortion,better tighter and smoother bass response. IMO High power drivers say the 18NLW8601 have high distortion compared to lower wattage and lower excursion drivers,they sacrifice quality of sound for high SPL.
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Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 1:36pm
	I have no experience with that driver as the TS Parameters never met up to my requirements. Knowing what driver will work best for your requirements based on the TS Parameters will offer more answers on how well a loudspeaker will perform under the given conditions. Many of times, people buy speakers based on what the majority use or hype without taking into consideration if they are using the exact enclosures, amplification, in addition to, application under the given scenario. Best Regards,
	Elliot Thompson

70,s hero Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 14 December 2014 Location: bristol Status: Offline Points: 637	Post Options Post Reply Quote 70,s hero Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 2:47pm
	Given that it has a 70mm excursion and what they call linear mathematical xmax of 14mm, a lager part of the VC remains outside of the field at any one given time.This will increase distortion
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Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 4:48pm
	I know many buy speakers based on xmax but it is foolhardy on their behalf to focus solely on a parameter that is not calculated to bring forth the Thiele Small Parameters. It appears wattage and xmax is the deciding factor in the eyes of many. However, neither of those figures holds any bearing on how the loudspeaker is going to sound in the enclosure unless the motive is to extract every bit of SPL from the loudspeaker. If that is the objective, you are bound to encounter distortion. One must have headroom not only from an amplifier standpoint but from a loudspeaker perspective as well, if the aim is to have minimum distortion. One must learn what the TS Parameters mean to attain the proper loudspeaker for his or her requirements. One must know what the graphs in a loudspeaker simulator are telling them in order to get an estimate on what to expect from a frequency response perspective. Best Regards,
	Elliot Thompson

70,s hero Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 14 December 2014 Location: bristol Status: Offline Points: 637	Post Options Post Reply Quote 70,s hero Report Post Thanks(0) Quote Reply Posted: 28 March 2015 at 5:47pm
	I think that xmax and excursion are very important measurements. If we look at xmax (the distance the voice coil can travel before it starts to leave the magnetic gap),then we can compare this with the maximum excursion figure.This will give us the measurement in terms of the portion of the coil that will be outside of the magnetic gap at any given time at or near maximum excursion. In the case of high power high excursion drivers this measurement is far in excess of lower power lower excursion drivers. We can see that in any 1hz cycle taking the 70mm excursion of an 18 sound driver that around 24 mm of the voice coil remains outside of the magnetic gap. i.e 24 mm of voice coil is outside of the magnetic gap at given intervals depending upon frequency. Given this the effects will be that those parts not subjected to the field uniformly will experience a lower temperature due to less inductance and therefore a lower r in comparison to the rest of the coil. This will cause a non linearity in the current flow within the coil and significantly contribute to distortion. From this I think that speakers that have the least amount of coil leaving the magnetic gap will attain a more linear response in isolation. We also have to consider that the power compression of the coil will be effected by the xmax figure in conjunction with the comparison of the max excursion as written beforehand.So whilst eithteen sound give power compression figures,they are careful in there claims of linearity where they concede that although the cone excursion is 70mm ... 42 mm of that is decidedly non linear and distorted by way of design.
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Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 29 March 2015 at 10:52am
	All of that has nothing to do with the TS Parameters that dictates how the loudspeaker going to sound in the enclosure. Bear in mind I do not try to extract every bit of SPL out of a single loudspeaker. I will use 4, 8, 16, or 32 woofers to achieve the SPL required for the job. When you use quantity, xmax is not issue regardless of mathematical mm of each driver for the workload is divided amongst all the speakers. This is why all my sub enclosures utilise two woofers in each cabinet. Sound Quality is first priority on my behalf. It appears you and I have different concepts on what we are aiming for. The length of the voice coil does not matter to me if the TS Parameters offered by the driver do not fit my requirements. Best Regards, Edited by Elliot Thompson - 29 March 2015 at 10:56am
	Elliot Thompson

70,s hero Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 14 December 2014 Location: bristol Status: Offline Points: 637	Post Options Post Reply Quote 70,s hero Report Post Thanks(0) Quote Reply Posted: 29 March 2015 at 6:16pm
	Cabinet design, is important, its not something that I have fully understood yet, so optimum wattage would be in terms of sound quality,that which allows the least amount of xmax within the intended enclosure,this would ensure the most linear response.
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Tarkovsky Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 30 June 2011 Location: Limehouse (LDN) Status: Offline Points: 513	Post Options Post Reply Quote Tarkovsky Report Post Thanks(0) Quote Reply Posted: 31 March 2015 at 9:02am
	Proper cabinet design and loading to the air mass will reduce cone/vc excursion. Reflex will quadruple in excursion per octave, whereas a properly loaded horns will only double. One of the man reasons horns outperform reflex IMO. That and that the air mass dampens the driver. I am assuming a well designed horn!