golden ratio. I dont get it - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th December 2012, 03:58 AM   #1
Account disabled at member's request
 
Join Date: Mar 2011
Location: Somewhere in Quebec
Default golden ratio. I dont get it

hi
my dimension for my bass (30 to 300hz) enclosure requirement is that the box is no more then 38cm wide and 82 heigt.

I want to have around 110 liter.

I dont know I to make the golden ratio, can anyone help

thanks
  Reply With Quote
Old 4th December 2012, 04:10 AM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
38 x 61.5 x 99.5 is golden ratio. If 18 mm ply, gross volume would be 191 litres,

If we start with 110 litre add 5 litre for bracing and back of driver then:

115 litre = 115,000 cm^3. Take the cube root = 48.6

48.6 x 1.618 = 78.7
48.6 / 1.618 = 30

So interior dimensions of 30 x 48.6 x 78.7 cm

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 4th December 2012, 11:27 AM   #3
diyAudio Member
 
speaker dave's Avatar
 
Join Date: Nov 2009
Location: The Mountain, Framingham
I don't get it either.

The golden ratio was originally for visually pleasing proportions. Put proper absorption in the cabinet (fiberglass) and don't worry about the dimension ratios.

David
  Reply With Quote
Old 4th December 2012, 11:33 AM   #4
DeonC is offline DeonC  South Africa
diyAudio Member
 
DeonC's Avatar
 
Join Date: May 2002
Location: Kimberley, South-Africa
Quote:
Originally Posted by planet10 View Post
38 x 61.5 x 99.5 is golden ratio. If 18 mm ply, gross volume would be 191 litres,

If we start with 110 litre add 5 litre for bracing and back of driver then:

115 litre = 115,000 cm^3. Take the cube root = 48.6

48.6 x 1.618 = 78.7
48.6 / 1.618 = 30

So interior dimensions of 30 x 48.6 x 78.7 cm

dave
Thanks, Dave. I did not start this thread, but find the info very useful. That method is so simple I wish I had thought about it.

Deon
__________________
I don't suffer from insanity. I enjoy every minute of it.
Have a look at my favorite thread: Interesting YouTube video clips
  Reply With Quote
Old 4th December 2012, 11:35 AM   #5
diyAudio Member
 
Mark.Clappers's Avatar
 
Join Date: Jan 2010
Location: The Netherlands, near the German border
The golden ratio spreads the internal standing waves in the frequency domain (ie they don't overlap, both the base and the harmonics). This is useful for mid-range but not so much for bass as the wavelengths involved are usually much larger then the enclosure size.
__________________
Music is art - Audio is psychoacoustics & engineering
  Reply With Quote
Old 4th December 2012, 11:51 AM   #6
balerit is offline balerit  South Africa
diyAudio Member
 
balerit's Avatar
 
Join Date: Apr 2011
Location: South Africa
Quote:
Originally Posted by speaker dave View Post
I don't get it either.

The golden ratio was originally for visually pleasing proportions. Put proper absorption in the cabinet (fiberglass) and don't worry about the dimension ratios.

David
I agree, it's for looks only, just another myth. I use Square root of 2 to propertion my bass reflex boxes. Also remember when you calculate a boxes volume it is the ideal volume and therefor everything that goes inside the box takes away from this ideal volume and you have to compensate for this by making the box larger, my free software does this for you.

Sample - The Book Worm
  Reply With Quote
Old 4th December 2012, 03:10 PM   #7
puppet is offline puppet  United States
diyAudio Member
 
Join Date: Dec 2011
Location: The Dells, WI
Quote:
Originally Posted by speaker dave View Post
I don't get it either.

The golden ratio was originally for visually pleasing proportions. Put proper absorption in the cabinet (fiberglass) and don't worry about the dimension ratios.

David
I've wondered about this, too. If you're just modeling a flat baffle for diffraction purposes (say for an OB), seems like the "golden ratio" doesn't produce an optimal response in sim. Might be fine to start there though.
  Reply With Quote
Old 4th December 2012, 03:21 PM   #8
diyAudio Member
 
Join Date: Sep 2006
Location: New England
When it comes to room acoustics, use of the GR to position speakers can be helpful.
__________________
"It's all about the music!"
  Reply With Quote
Old 4th December 2012, 03:56 PM   #9
diyAudio Member
 
Join Date: Dec 2005
Location: Plymouth, England
Quote:
Originally Posted by speaker dave View Post
I don't get it either.

The golden ratio was originally for visually pleasing proportions. Put proper absorption in the cabinet (fiberglass) and don't worry about the dimension ratios.

David
Wasn't it for concert halls? Unlike Victorian structures, such as the Albert Hall.
  Reply With Quote
Old 4th December 2012, 06:23 PM   #10
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
I always thought it was observed in ancient egyptian design, adopted by the greeks, and used visually to proportion windows, paintings etc. Ive never tested if it really works in acoustics. My favourite adaptation of GL is to halve the longest length, calculating for twice the volume. Its a nice way to get a more cube-like shape. Of course standing waves would be more bunched up, but i never heard a problem. GL is better than guesswork, or breaking the 'rules' i.e. W equally a third H for example.
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
The Golden Ratio of 1.618 PrecisionAudio Multi-Way 43 11th October 2012 04:15 PM
The Golden Ratio Stage Stee Solid State 7 22nd February 2009 09:46 PM
Golden Ratio Height edjosh23 Full Range 13 3rd February 2009 10:52 PM
Golden Box Ratio - Important or not? Ornlu Subwoofers 5 27th May 2005 07:52 AM
Golden ratio - Example? icebear Multi-Way 5 17th April 2004 09:40 PM


New To Site? Need Help?

All times are GMT. The time now is 12:46 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2