Are all reflex subwoofers just the product of the Thiele Small parameters? As if to say anybody (qualified) can design a reflex subwoofer using Thiele Small parameters to make it work the way they want it to?
Reflex Subwoofers ?
- Thread starter Brandon G Romanowski
- Start date
Tim Weaver
Senior
Re: Reflex Subwoofers ?
Yes.
Although just like everything else, there are good designs and bad. The best designs take into account how the woofer reacts with the box volume and tuning while the voice coil is hot and power compression has set in. The behavior of the woofer changes with temperature.
Also, a good design has an extremely stiff, non-resonant box while still trying to be lightweight, truck pack sized, and roady-friendly. Trying to fit all these criteria in a box and still have room for the ports is a tough job sometimes.
Yes.
Although just like everything else, there are good designs and bad. The best designs take into account how the woofer reacts with the box volume and tuning while the voice coil is hot and power compression has set in. The behavior of the woofer changes with temperature.
Also, a good design has an extremely stiff, non-resonant box while still trying to be lightweight, truck pack sized, and roady-friendly. Trying to fit all these criteria in a box and still have room for the ports is a tough job sometimes.
Re: Reflex Subwoofers ?
Brandon,
I've written two articles for FOH, one in October issue, and one in November issue, that discuss some of the aspects vented box design, and what limits their performance. Since FOH is free, I suggest checking out both. In the course of drafting the October article, I prepared winISD files for a pretty good fraction of the existing pro sound woofers. Freely available for download at http://www.passbandllc.com/winisd.zip and ready for playing around in winISD Pro.
Strictly speaking, what we see on datasheets is a mishmash of the small signal electro-mechanical parameters, and the derived T-S parameters. The T-S parameters are calculated from the electro-mechanical parameters. In a broad sense, the e-m parameters are about driver behavior, and the derived T-S are about the box driver behavior combination.
If you are looking to do something specific, PM me offline, and we can chat.
Brandon,
I've written two articles for FOH, one in October issue, and one in November issue, that discuss some of the aspects vented box design, and what limits their performance. Since FOH is free, I suggest checking out both. In the course of drafting the October article, I prepared winISD files for a pretty good fraction of the existing pro sound woofers. Freely available for download at http://www.passbandllc.com/winisd.zip and ready for playing around in winISD Pro.
Strictly speaking, what we see on datasheets is a mishmash of the small signal electro-mechanical parameters, and the derived T-S parameters. The T-S parameters are calculated from the electro-mechanical parameters. In a broad sense, the e-m parameters are about driver behavior, and the derived T-S are about the box driver behavior combination.
If you are looking to do something specific, PM me offline, and we can chat.
Re: Reflex Subwoofers ?
Here's a WINisd question I always had:
Obviously when you design a cabinet, you figure out the internal volume and deduct handles, bracing, HF components, etc.
When you run WINisd it asks you for the driver model, and the internal volume of the box and spits out a port length at whatever diameter you specify.
Is the WINisd program automatically deducting the additional volume displaced by the driver and ports when it gives you the calculated tuning values?
Here's a WINisd question I always had:
Obviously when you design a cabinet, you figure out the internal volume and deduct handles, bracing, HF components, etc.
When you run WINisd it asks you for the driver model, and the internal volume of the box and spits out a port length at whatever diameter you specify.
Is the WINisd program automatically deducting the additional volume displaced by the driver and ports when it gives you the calculated tuning values?
As far as I know, WINisd doesn't take the driver or port volume into account.
Sent from my DROID2 GLOBAL
Sent from my DROID2 GLOBAL
Re: Reflex Subwoofers ?
No;
Enclosure volume is the free volume in the enclosure. It does not account for handles, ports, drivers, bracing, etc. If WinISD says your box needs to be 250L, and the port volume is, say, 50L, and the driver volume is 10L, then the resultant box will be at least 250+50+10=310L internal volume, plus bracing.
No;
Enclosure volume is the free volume in the enclosure. It does not account for handles, ports, drivers, bracing, etc. If WinISD says your box needs to be 250L, and the port volume is, say, 50L, and the driver volume is 10L, then the resultant box will be at least 250+50+10=310L internal volume, plus bracing.