Help interpreting speaker data - diyAudio
Go Back   Home > Forums > Design & Build > Software Tools

Software Tools SPICE, PCB CAD, speaker design and measurement software, calculators

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 15th June 2012, 11:24 PM   #1
diyAudio Member
 
Join Date: May 2012
Default Help interpreting speaker data

I'm thinking of building some cheap bookshelf-style speakers for above the test bench and was attracted to some low-price ($30) 5" woofer/midrange devices. But, as a newbie to enclosure design, I'm having difficulty interpreting the data provided on-line. Most of the parameters are clearly stated:

Specifications
• Nominal impedance: 8 ohms
• Power nominal: 50WRMS
• Frequency response: 70Hz - 7kHz
• Sensitivity: 88dB (1W@1m)
• Qms: 1.404
• Qes:0.717
• Qts: 0.474
• Fs: 67.63Hz

The missing ingredient, Vas, is given at the bottom of the Impedance vs Freq graph as "Vas=7.266m M". See:

http://www.jaycar.com.au/products_up...0parameter.pdf

Can someone familiar with similarly-sized drivers suggest what unit of measurement must be intended here? Being a Volume, I'd be expecting Litres, Cubic Metres or something similar. But what's an "m M"?

They also give the dimensions according to some convention I'm not familiar with:

Dimensions:
• A= 145
• B= 136
• C= 120
• D= 56

Would I be right in assuming that:

• A= 145 is outside diameter of basket
• B= 136 is diameter of the circle of mounting holes
• C= 120 is diameter of cone (5" = ~125mm)
• D= 56 is front-to-back (ie depth)?

Terry
  Reply With Quote
Old 16th June 2012, 03:19 AM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Some of the units are strange on the graph. For that size driver Vas is likely 7-some litre. SOmewhere they will have a key to ABCD, your interpretation is likely correct except that C is likely the cut-piy diameter.

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 16th June 2012, 06:54 AM   #3
diyAudio Member
 
Join Date: May 2012
Great, thanks Dave. I'll plug that in and see if it makes sense.

You had me puzzled with "the cut-piy diameter". Oooh, I thought, another loudspeaker technical expression I'm unfamiliar with. But, checking the keyboard, I note that the letters "o.u.t." are all one to the left of the letters "p.i.y.". (Pesky, finding those dashes, isn't it!)

So, I'm going to proceed on the basis that 120mm is the cut-out diameter. It certainly makes more sense than my guess!

Terry
  Reply With Quote
Old 16th June 2012, 07:04 AM   #4
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by Terry McGee View Post
You had me puzzled with "the cut-piy diameter". Oooh, I thought, another loudspeaker technical expression I'm unfamiliar with. But, checking the keyboard, I note that the letters "o.u.t." are all one to the left of the letters "p.i.y.". (Pesky, finding those dashes, isn't it!)


Very perceptive of you, and exactly what happened... i took grade 11 math insteadof grade 10 typing, and when on the laptop in low light my already poor typing becomes worse.

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 17th June 2012, 07:13 AM   #5
taj is offline taj
diyAudio Member
 
taj's Avatar
 
Join Date: Feb 2005
I never would have figured that out. I'd be torturing my poor already-abused brain on p.i.y. acronyms for the next month.

..Todd
  Reply With Quote
Old 17th June 2012, 07:20 AM   #6
diyAudio Member
 
Join Date: May 2012
Heh heh. The only good thing about getting old is you get very, very sneaky....

Terry
  Reply With Quote
Old 17th June 2012, 07:28 AM   #7
diyAudio Member
 
Join Date: May 2012
Hmmm. Proceeding on the basis of the dimensions given, I get a 12.37 litre box, a port diameter of 25mm (1") and a port length of 1.61cm, suspiciously close to the thickness of the wood I specified, 16mm (5/8"). I guess that's just telling me to drill a 25mm (1") hole in the box? Or should I get suspicious?

Terry
  Reply With Quote
Old 17th June 2012, 08:00 AM   #8
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by Terry McGee View Post
Hmmm. Proceeding on the basis of the dimensions given, I get a 12.37 litre box, a port diameter of 25mm (1") and a port length of 1.61cm, suspiciously close to the thickness of the wood I specified, 16mm (5/8"). I guess that's just telling me to drill a 25mm (1") hole in the box? Or should I get suspicious?
Terry,

That is an OK looking sim.

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 17th June 2012, 08:53 AM   #9
diyAudio Member
 
Join Date: May 2012
Thanks Dave

I'll go chop down a tree in anticipation...

Terry
  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
Difficulty interpreting pulse and frequency response data ByronInPortland Multi-Way 5 11th April 2011 05:35 PM
Meassuring speaker data jurriaan Construction Tips 1 7th October 2010 05:16 PM
KEF speaker data ? promitheus Multi-Way 16 9th January 2009 10:32 PM
Speaker Data Help ?? papanohn Multi-Way 6 24th December 2006 10:33 AM


New To Site? Need Help?

All times are GMT. The time now is 02:43 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