sub series / parallel Qts parameter - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 30th April 2004, 08:08 PM   #1
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Default sub series / parallel Qts parameter

Given a dual voice driver has fixed Vas and Fs parameters,
I assume there is a simple relationship between Qts for
series and parallel connection but I don't know what is is.

Assuming Qms is high so Qts ~ = Qe whats the relationship ?

sreten.
  Reply With Quote
Old 30th April 2004, 11:22 PM   #2
Svante is offline Svante  Sweden
diyAudio Member
 
Svante's Avatar
 
Join Date: Feb 2004
Location: Stockholm
I think the key is in BL and Re.
B is always constant.
Qes=w0*Mms/((BL)^2/Re)=w0*Mms * Re/(BL)^2

Compared to single coil:
Series connection:
L is doubled, so BL is doubled. Re is doubled.
So Qes is halved

Parallel connection:
L and BL is the same*. Re is halved
So Qes is halved

This should mean that both Qes and Qts are the same for the dual coil driver regardless of series or parallel connection.

This also makes sense in that 4 and 8 ohm versions of drivers usually have the same Qts, even though the number of windings has been changed.

*See the two windings as running close to each other in parallel. This would mean that the voltage at any given point along the wire would be the same in both wires. So we can join them together in one thicker wire without changing the behaviour. Alternatively the length can be seen as doubled and the current as halved. A halved current is equivalent to a halved B, so BL is the same.

This is just taken from the back of my head at 01:20 at night, so I might have got it wrong. I have a faint memory of that I saw this explained on some site describing the Shiva driver, that could be good to look up too.
__________________
Simulate loudspeakers: Basta!
Simulate the baffle step: The Edge
  Reply With Quote
Old 30th April 2004, 11:29 PM   #3
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Imagine how Re and BL change.
Attached Files
File Type: zip dvcpublic.zip (4.4 KB, 15 views)
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 1st May 2004, 05:46 AM   #4
f4ier is offline f4ier  Australia
diyAudio Member
 
f4ier's Avatar
 
Join Date: Sep 2001
Location: Sydney
le'me know what you think of this one
__________________
Crossover/Subwoofer Simulator
  Reply With Quote
Old 1st May 2004, 08:41 AM   #5
Svante is offline Svante  Sweden
diyAudio Member
 
Svante's Avatar
 
Join Date: Feb 2004
Location: Stockholm
f4ier:
Hmm. If Qes is the same in the two configs, at Qms also is, mustn't Qts be the same too? (two first images)
__________________
Simulate loudspeakers: Basta!
Simulate the baffle step: The Edge
  Reply With Quote
Old 1st May 2004, 01:14 PM   #6
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Isaac,

I think in the configuration with one amplifier connected to each coil, with separate signals, you need to use the same parameters as when one coil is shorted (with a resistor equal to the output impedance of the amp). If both channels play the exact same signal, it would be the same as parallel connected case driven by one amplifier, but the impedance to each amp is double...
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 3rd May 2004, 11:50 AM   #7
f4ier is offline f4ier  Australia
diyAudio Member
 
f4ier's Avatar
 
Join Date: Sep 2001
Location: Sydney
Svante, yep, Qts for both configurations is the same, I included the equation for Qts in the first set of parameters just for convenience (so that the reader doesn't have to scan the text to find the Qts equation).

Ron, section 1f is consistent with your point, but I failed to make it just as specific. I'll clarify 1f and its corresponding column in the table as soon as possible, that page needs to be updated anyway. Thanks for point that out.

__________________
Crossover/Subwoofer Simulator
  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
Three 10" 4Ohm subs, wired in series or series-parallel? Nagamitsu Car Audio 38 19th February 2014 11:16 PM
series or parallel? medicman Tubes / Valves 5 22nd January 2009 04:42 PM
Series vs parallel? legendaryfrog Full Range 5 14th December 2006 02:50 PM
series vs parallel SPL? 2litre Multi-Way 16 22nd February 2006 09:58 AM
What would you do? series/parallel MtnBob Multi-Way 13 14th April 2005 10:17 PM


New To Site? Need Help?

All times are GMT. The time now is 09:25 AM.


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