What is Vas (liters) on a sub?

Flyin11 · 16th February 2008, 10:26 PM

I understand the definiton of Vas (liters) on Crutchfield's site:

Volume Acoustic Suspension - the volume of air having the same stiffness as the speaker's suspension (measured in liters).

Now, my big question is...What is better on a sub...More or less of a Vas rating? Just wondering cause there is a huge difference that I'm seeing in my sub's Vas rating compared to others.

sdoom · 16th February 2008, 11:45 PM

You cannot say "better" or "worse". The different values are the result of the speaker design, e.g. some speakers have stiffer spiders than others or the stroke may be larger on one speaker than it is at another.

Usually "soft" spidered speakers have more stroke than stronger spidered speakers. Nowadays , with lots of power generated by huge amplifiers, speaker designers can create very hard spidered speakers with still a lot of moving mass, which usually totals in a decrease in overall efficiency , but an increase at very low frequencies. Kicker´s early subwoofers used to be built like that.

jol50 · 17th February 2008, 03:55 PM

I would recommend you get winISD and plug some drivers into it, including ones you have/have used. This will show you what the different drivers and boxes do. The softer a suspension the easier the motor can move the cone...and lighter cone may have softer with less mass to move/control. More efficient but also depends on what you will do with it. That will work in a sealed box because the box helps support the cone, but running it IB the cone may get out of control easily. In general that is a good reason to match your drivers with the power you will use on them, just like you need to match the enclosure type. Some drivers can go either way, some can't very well as far as enclosure. An efficient driver can put out respectable sound with limited power but can't handle more....a typical one. Some drivers are better than others. So if yours is different then it may do better with a specific box type than another.

Flyin11 · 18th February 2008, 01:52 AM

I would if I could find the dern program

If you have to pay for it, I'm not worried about it. I tried looking for the program on Yahoo but only got some page that had WinISD in the command line but that only explained a few things about the program..No where to download it...

MJL21193 · 18th February 2008, 02:04 AM

If you have Excel, you can use Unibox.

Many like it better.

16th February 2008, 10:26 PM	#1
Flyin11 diyAudio Member Join Date: Sep 2007	What is Vas (liters) on a sub? I understand the definiton of Vas (liters) on Crutchfield's site: Volume Acoustic Suspension - the volume of air having the same stiffness as the speaker's suspension (measured in liters). Now, my big question is...What is better on a sub...More or less of a Vas rating? Just wondering cause there is a huge difference that I'm seeing in my sub's Vas rating compared to others.

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16th February 2008, 11:45 PM	#2
sdoom diyAudio Member Join Date: Mar 2004 Location: Heidelberg	You cannot say "better" or "worse". The different values are the result of the speaker design, e.g. some speakers have stiffer spiders than others or the stroke may be larger on one speaker than it is at another. Usually "soft" spidered speakers have more stroke than stronger spidered speakers. Nowadays , with lots of power generated by huge amplifiers, speaker designers can create very hard spidered speakers with still a lot of moving mass, which usually totals in a decrease in overall efficiency , but an increase at very low frequencies. Kicker´s early subwoofers used to be built like that.

17th February 2008, 03:55 PM	#3
jol50 diyAudio Member Join Date: Nov 2007	I would recommend you get winISD and plug some drivers into it, including ones you have/have used. This will show you what the different drivers and boxes do. The softer a suspension the easier the motor can move the cone...and lighter cone may have softer with less mass to move/control. More efficient but also depends on what you will do with it. That will work in a sealed box because the box helps support the cone, but running it IB the cone may get out of control easily. In general that is a good reason to match your drivers with the power you will use on them, just like you need to match the enclosure type. Some drivers can go either way, some can't very well as far as enclosure. An efficient driver can put out respectable sound with limited power but can't handle more....a typical one. Some drivers are better than others. So if yours is different then it may do better with a specific box type than another.

18th February 2008, 01:52 AM	#4
Flyin11 diyAudio Member Join Date: Sep 2007	I would if I could find the dern program If you have to pay for it, I'm not worried about it. I tried looking for the program on Yahoo but only got some page that had WinISD in the command line but that only explained a few things about the program..No where to download it...

18th February 2008, 02:04 AM	#5
MJL21193 Account disabled at member's request Join Date: Mar 2007	If you have Excel, you can use Unibox. Many like it better.

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