Program for designing box by desired Q?

prickears · 27th March 2011, 07:23 AM

Does anyone know of a box program that can recommend a box size and port size by entering desired Q?

many thanks.

Mick.

kelticwizard · 27th March 2011, 04:26 PM

By desired Q I assume you mean the Qts of the driver.

Just about all of them will do that, as I recall, but you also have to enter such things as the free air resonance, (Fs), and the volume of acoustic something or other, (Vas).

infinia · 27th March 2011, 04:48 PM

Q implies a second order system. meaning closed box ie no reflex ports and such.
Qts and Fs of a driver placed in a sealed or closed box will be raised by the apparent air volume.

WinSD beta works and is easy >google speaker box modeling software

AndrewT · 27th March 2011, 04:59 PM

winisdpro from linear team.

infinia · 27th March 2011, 05:02 PM

beta is the version to play with basic box parameters, WinISD pro is very difficult for newbies.

AuroraB · 27th March 2011, 06:40 PM

Quote:

Originally Posted by infinia

Q implies a second order system.

Q is the general term for the whole system, which mostly describes the system behaviour around the lower f3 - of the total system..........which can be anythinng from fisrt order and upwards....
BRs are usually 4. order....

kelticwizard · 27th March 2011, 08:56 PM

Q might imply a closed box system to an experienced builder familiar with Thiele and Small. However, I think there is a chance that prickears is just getting started with this, has a woofer with a listing for "Q", (Qts), and would like a box volume and port size for it. Most programs will tell him that, if you list Fs and Vas as well.

Perhaps the best thing would be for prickears to list the specifications for his woofer and somebody here can tell him box volume, port size and length. I would offer to do so, but until my new netbook comes in from Amazon I am using an old iMac eggshell with antiquated OS and software, and I doubt I'll be able to download any box programs on it.

prickears · 27th March 2011, 10:15 PM

Thanx guys,

Actually, I generally use Unibox, it seems most basic programs give you a max flat alignment for a ported box, (butterworth QB3?) I think all BR's are 4th order, but the shape of the slope can be fiddled, and that is what I am interested in.

I am dealing with a room that doesn't mind boosting the bass quite a bit, and in fact 'max flat', in this case is just too boomy, so I figured I might try for an earlier but slower shape to tighten up the bass and drag a bit of boomy-ness out of it. So yeah, really just an attempt to get the room and system to merge together a little better, but I don't want to thin out the bass too much, if that makes sense.

Mick.

infinia · 28th March 2011, 12:26 AM

Hi Prickears
I too use Unibox but I find WinISD beta easier to experiment with the basics to optimize things quicker ie fiddle, then take the parameters found back to Unibox to finalize and cross check the design.

infinia · 28th March 2011, 12:41 AM

Hi AuroraB
yes you can measure Q for any resonance f/BW, but there are no equations other than a 2nd order system to design with.

27th March 2011, 07:23 AM	#1
prickears diyAudio Member Join Date: Jun 2009 Location: Hamilton, victoria	Program for designing box by desired Q? Does anyone know of a box program that can recommend a box size and port size by entering desired Q? many thanks. Mick. __________________ Making stuff 'idiot proof', Just breeds more effective idiots.

27th March 2011, 04:26 PM	#2
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	By desired Q I assume you mean the Qts of the driver. Just about all of them will do that, as I recall, but you also have to enter such things as the free air resonance, (Fs), and the volume of acoustic something or other, (Vas). __________________ "A friend will help you move. A really good friend will help you move a body." -Anonymous

27th March 2011, 04:48 PM	#3
infinia diyAudio Member Join Date: May 2005 Location: Californication	Q implies a second order system. meaning closed box ie no reflex ports and such. Qts and Fs of a driver placed in a sealed or closed box will be raised by the apparent air volume. WinSD beta works and is easy >google speaker box modeling software __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

27th March 2011, 04:59 PM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	winisdpro from linear team. __________________ regards Andrew T.

27th March 2011, 05:02 PM	#5
infinia diyAudio Member Join Date: May 2005 Location: Californication	beta is the version to play with basic box parameters, WinISD pro is very difficult for newbies. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust


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27th March 2011, 08:56 PM	#7
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	Q might imply a closed box system to an experienced builder familiar with Thiele and Small. However, I think there is a chance that prickears is just getting started with this, has a woofer with a listing for "Q", (Qts), and would like a box volume and port size for it. Most programs will tell him that, if you list Fs and Vas as well. Perhaps the best thing would be for prickears to list the specifications for his woofer and somebody here can tell him box volume, port size and length. I would offer to do so, but until my new netbook comes in from Amazon I am using an old iMac eggshell with antiquated OS and software, and I doubt I'll be able to download any box programs on it. __________________ "A friend will help you move. A really good friend will help you move a body." -Anonymous

27th March 2011, 10:15 PM	#8
prickears diyAudio Member Join Date: Jun 2009 Location: Hamilton, victoria	Thanx guys, Actually, I generally use Unibox, it seems most basic programs give you a max flat alignment for a ported box, (butterworth QB3?) I think all BR's are 4th order, but the shape of the slope can be fiddled, and that is what I am interested in. I am dealing with a room that doesn't mind boosting the bass quite a bit, and in fact 'max flat', in this case is just too boomy, so I figured I might try for an earlier but slower shape to tighten up the bass and drag a bit of boomy-ness out of it. So yeah, really just an attempt to get the room and system to merge together a little better, but I don't want to thin out the bass too much, if that makes sense. Mick. __________________ Making stuff 'idiot proof', Just breeds more effective idiots.

28th March 2011, 12:26 AM	#9
infinia diyAudio Member Join Date: May 2005 Location: Californication	Hi Prickears I too use Unibox but I find WinISD beta easier to experiment with the basics to optimize things quicker ie fiddle, then take the parameters found back to Unibox to finalize and cross check the design. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

28th March 2011, 12:41 AM	#10
infinia diyAudio Member Join Date: May 2005 Location: Californication	Hi AuroraB yes you can measure Q for any resonance f/BW, but there are no equations other than a 2nd order system to design with. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

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