Bullock's Equations No Good?

richie00boy · 24th August 2006, 05:12 PM

Bob Bullock's book 'Bullock on Boxes' written a good 10+ years ago, has some equations for predicting excursion and thermal power handling as well as the usual frequency response and max SPL, all against frequency. These do not give results anything close to WinISD Pro, especially the excursion and power ones.

Are Bullock's equations based on outdated and incorrect theory?

Ron E · 24th August 2006, 08:29 PM

I would trust Bullock before WinISD pro.

My own sims (self written) do not match WinISD, nor do they match Bassbox. Just as a check, I confirmed my own sim with sims run by D'Appolito using LEAP's "quickbox" sims in several speaker builder articles.

Some people use RMS rather than Peak excursion - so the results may differ by a factor of 1.414. Bullock uses RMS in his sim programs.....

richie00boy · 24th August 2006, 11:03 PM

Thanks for the input. Even taking the RMS vs peak Xmax into account, I think it's still off what WinISD predicts, but I need to do some proper checking on that.

Why would you trust Bullock over WinISD?

Ron E · 25th August 2006, 12:06 AM

Because the lazy amateurs who wrote WinISD have no credibility.
Bullock has lots.

Never rule out a mathematical error on your part....

richie00boy · 25th August 2006, 07:56 AM

Thanks again. I checked, double- and triple-checked my calculations. I think they are OK.

24th August 2006, 05:12 PM	#1
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Bullock's Equations No Good? Bob Bullock's book 'Bullock on Boxes' written a good 10+ years ago, has some equations for predicting excursion and thermal power handling as well as the usual frequency response and max SPL, all against frequency. These do not give results anything close to WinISD Pro, especially the excursion and power ones. Are Bullock's equations based on outdated and incorrect theory? __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

24th August 2006, 08:29 PM	#2
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	I would trust Bullock before WinISD pro. My own sims (self written) do not match WinISD, nor do they match Bassbox. Just as a check, I confirmed my own sim with sims run by D'Appolito using LEAP's "quickbox" sims in several speaker builder articles. Some people use RMS rather than Peak excursion - so the results may differ by a factor of 1.414. Bullock uses RMS in his sim programs..... __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

24th August 2006, 11:03 PM	#3
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Thanks for the input. Even taking the RMS vs peak Xmax into account, I think it's still off what WinISD predicts, but I need to do some proper checking on that. Why would you trust Bullock over WinISD? __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

25th August 2006, 12:06 AM	#4
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	Because the lazy amateurs who wrote WinISD have no credibility. Bullock has lots. Never rule out a mathematical error on your part.... __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

25th August 2006, 07:56 AM	#5
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Thanks again. I checked, double- and triple-checked my calculations. I think they are OK. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more


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