Daydreaming again

Moondog55 · 6th October 2011, 07:04 PM

Replacement Woofer for 15" Realistic Mach One 4 Ohm 290-182

I saw that these are on sale.

I was just wondering to myself why??
For some reason the sound of a high "Q" driver in a large closed box just 'sounds' right.
Perhaps that is because my musical tastes are firmly rooted in 60s and 70s Rock & Roll and I grew up to the thunder of Pink Floyd and Mike Oldfields "Tubular Bells"

The Realistic Mach one were not the best speaker I ever heard when I was a kid but they did have the best bass, so what was I hearing? A big mid-bass peak or did they truly rumble and thunder as I remember??

dirkwright · 6th October 2011, 07:37 PM

Well, Fs is 20Hz.... so maybe there's hope...

David Gatti · 6th October 2011, 07:39 PM

15" woofer in a big box has the effortlessness, the way nature intended it, like a big V8.

mashaffer · 7th October 2011, 12:10 AM

Looks pretty nice in 15 ft^3 sealed and very nice in 30 ft^3 (give or take) ported. A little bit larger than the original enclosure.

Assuming the original enclosure was about 4 ft^3 sealed then it still looks reasonable down to a bit below 40Hz but would be down about 6dB lower at 20Hz than the optimum size.

Moondog55 · 7th October 2011, 12:21 AM

Much larger than the original enclosure size;LOL; which was ( I'm guessing here ) about the 4cubic feet but fully stuffed.
But why did I think they sounded so good??
I haven't seen a waterfall of the replacement drivers so no idea of the XO needed or at what point they should change to the mid but the old ballpark of 300 -- 3000 springs to mind

gainphile · 7th October 2011, 01:03 AM

Fs of 20hz and critically-damped Qts of 0.5 is perfect for dipoles !!

That would give you -6db at 20hz.

AllenB · 7th October 2011, 01:18 AM

This might help with the crossover frequencies.

Realistic Mach One SpeakersAmerican Bosch 670T Radio

Moondog55 · 7th October 2011, 01:22 AM

800 and 8k
Wow is all I can say,

AllenB · 7th October 2011, 01:30 AM

800 is a good place to cross from a dispersion matching point of view. Finding the right 15" to do it would have been the issue. I guess this explains the ribs on the cone, and if I didn't misread something they may have been made by fostex?

Not that I wouldn't question their ideas on dispersion. Their horizontal line arrays in the later models are interesting to say the least from a domestic point of view.

Moondog55 · 7th October 2011, 01:47 AM

Fostex may be right, shame I can't afford any of these

6th October 2011, 07:04 PM	#1
Moondog55 diyAudio Member Join Date: Jun 2007 Location: Norlane; Geelong: Victoria: Australia	Daydreaming again Replacement Woofer for 15" Realistic Mach One 4 Ohm 290-182 I saw that these are on sale. I was just wondering to myself why?? For some reason the sound of a high "Q" driver in a large closed box just 'sounds' right. Perhaps that is because my musical tastes are firmly rooted in 60s and 70s Rock & Roll and I grew up to the thunder of Pink Floyd and Mike Oldfields "Tubular Bells" The Realistic Mach one were not the best speaker I ever heard when I was a kid but they did have the best bass, so what was I hearing? A big mid-bass peak or did they truly rumble and thunder as I remember?? __________________ QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"

7th October 2011, 12:10 AM	#4
mashaffer diyAudio Member Join Date: Jun 2004 Location: Indiana	Looks pretty nice in 15 ft^3 sealed and very nice in 30 ft^3 (give or take) ported. A little bit larger than the original enclosure. Assuming the original enclosure was about 4 ft^3 sealed then it still looks reasonable down to a bit below 40Hz but would be down about 6dB lower at 20Hz than the optimum size. __________________ mike - www.keepingsundayspecial.org

7th October 2011, 12:21 AM	#5
Moondog55 diyAudio Member Join Date: Jun 2007 Location: Norlane; Geelong: Victoria: Australia	Much larger than the original enclosure size;LOL; which was ( I'm guessing here ) about the 4cubic feet but fully stuffed. But why did I think they sounded so good?? I haven't seen a waterfall of the replacement drivers so no idea of the XO needed or at what point they should change to the mid but the old ballpark of 300 -- 3000 springs to mind __________________ QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"

7th October 2011, 01:03 AM	#6
gainphile diyAudio Member Join Date: Dec 2007 Location: Melbourne the sunny city!	Fs of 20hz and critically-damped Qts of 0.5 is perfect for dipoles !! That would give you -6db at 20hz. __________________ http://gainphile.blogspot.com

7th October 2011, 01:22 AM	#8
Moondog55 diyAudio Member Join Date: Jun 2007 Location: Norlane; Geelong: Victoria: Australia	800 and 8k Wow is all I can say, __________________ QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"


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6th October 2011, 07:37 PM	#2
dirkwright diyAudio Member Join Date: May 2011 Location: Virginia	Well, Fs is 20Hz.... so maybe there's hope...

6th October 2011, 07:39 PM	#3
David Gatti diyAudio Member Join Date: Mar 2004 Location: Melbourne, Australia	15" woofer in a big box has the effortlessness, the way nature intended it, like a big V8.

7th October 2011, 01:18 AM	#7
AllenB diyAudio Member Join Date: Oct 2008	This might help with the crossover frequencies. Realistic Mach One SpeakersAmerican Bosch 670T Radio

7th October 2011, 01:30 AM	#9
AllenB diyAudio Member Join Date: Oct 2008	800 is a good place to cross from a dispersion matching point of view. Finding the right 15" to do it would have been the issue. I guess this explains the ribs on the cone, and if I didn't misread something they may have been made by fostex? Not that I wouldn't question their ideas on dispersion. Their horizontal line arrays in the later models are interesting to say the least from a domestic point of view.

7th October 2011, 01:47 AM	#10
Moondog55 diyAudio Member Join Date: Jun 2007 Location: Norlane; Geelong: Victoria: Australia	Fostex may be right, shame I can't afford any of these __________________ QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"

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