WIN ISD
Hoooee am I having fun with it. The 200 plus liter box allows a Qtc of .6 Does this equate to "fast" ? My limited knowledge says Qtc is the "fast factor"
Ported systems don't seem to have this number. What is the equivalent transient responce of a vented cabinet? Or does that vary too?
Hoooee am I having fun with it. The 200 plus liter box allows a Qtc of .6 Does this equate to "fast" ? My limited knowledge says Qtc is the "fast factor"
Ported systems don't seem to have this number. What is the equivalent transient responce of a vented cabinet? Or does that vary too?
Mark,
Change the plot window from displaying SPL to displaying "Group Delay"
Most sealed cabinets are rarely more than 5ms behind the primary response.
Once you start going to ports you'll see huge delays build up here. That's more your "fast factor" than Qtc will be.
BTW, if you change the design window to "Box" then you can alter parameters on the fly and watch what it does to the response in real time. This is a big advantage over the older ISD.
I'm assuming that you haven't disucssed twin 44's with your wife then...
Drew
Change the plot window from displaying SPL to displaying "Group Delay"
Most sealed cabinets are rarely more than 5ms behind the primary response.
Once you start going to ports you'll see huge delays build up here. That's more your "fast factor" than Qtc will be.
BTW, if you change the design window to "Box" then you can alter parameters on the fly and watch what it does to the response in real time. This is a big advantage over the older ISD.
I'm assuming that you haven't disucssed twin 44's with your wife then...
Drew
I'm still alive!
Well, industrial drums are an especially bad shape, but that is a scary image.Thanks for the explanation. on the fast stuff.
Pascal and I are very close to deciding on the PR300 MO I think.
It is 97db efficient, but a lot smaller than the 15" version
Here's the good news: My parents gave me their old "Stereo Cabinet" they had custom made in the mid '60's which we have in our living room. (lounge room?) This is a beautiful piece of furniture, about 8.5' long with doors on each end facing forward, that you open to expose the speakers. While I wouldn't consider putting speakers in such a hole normally, I think I could just put the woofer boxes in them, and have the Fostex's and tweeters in a baffle on stands that I can place in front when they are used. As long as they are in front of the woofers, I think it will work out. OK, they won't have perfect phase response, but the woofers are almost subs, since they start to roll off at 200hz.
The spaces will accomodate a 1" thick walled box with about 140 liters internal. Do I have to add the volume of the cone and vent to the win ISD numbers? So if the Win ISD says I need 135 liters do I really need 135+cone volume + vent volume?
It looks like vented we would get 40hz. at -3dB
sealed we would get 48hz at -3dB. I like the option of putting a plug in the port and seeing the difference between the two.
Too bad my parents sold the Fisher tube receiver they used in the cabinet!!
Well, industrial drums are an especially bad shape, but that is a scary image.Thanks for the explanation. on the fast stuff.
Pascal and I are very close to deciding on the PR300 MO I think.
It is 97db efficient, but a lot smaller than the 15" version
Here's the good news: My parents gave me their old "Stereo Cabinet" they had custom made in the mid '60's which we have in our living room. (lounge room?) This is a beautiful piece of furniture, about 8.5' long with doors on each end facing forward, that you open to expose the speakers. While I wouldn't consider putting speakers in such a hole normally, I think I could just put the woofer boxes in them, and have the Fostex's and tweeters in a baffle on stands that I can place in front when they are used. As long as they are in front of the woofers, I think it will work out. OK, they won't have perfect phase response, but the woofers are almost subs, since they start to roll off at 200hz.
The spaces will accomodate a 1" thick walled box with about 140 liters internal. Do I have to add the volume of the cone and vent to the win ISD numbers? So if the Win ISD says I need 135 liters do I really need 135+cone volume + vent volume?
It looks like vented we would get 40hz. at -3dB
sealed we would get 48hz at -3dB. I like the option of putting a plug in the port and seeing the difference between the two.
Too bad my parents sold the Fisher tube receiver they used in the cabinet!!
The bad news is just as you imagined.
you need to minus the volume of any reflex ports/vents you build in, driver cones, driver magnets and bracing.
if you use stuffing like dacron, long hair wool etc you can fool the box into thinking that it's about 20% larger than it really is (don't ask me how but that's the rule of thumb)
Be very wary of stuffing reflex/ported cabinets with anything though, it seems to kill the dynamics and slow things down even further. Much more a sealed box kind of trick.
drew
you need to minus the volume of any reflex ports/vents you build in, driver cones, driver magnets and bracing.
if you use stuffing like dacron, long hair wool etc you can fool the box into thinking that it's about 20% larger than it really is (don't ask me how but that's the rule of thumb)
Be very wary of stuffing reflex/ported cabinets with anything though, it seems to kill the dynamics and slow things down even further. Much more a sealed box kind of trick.
drew
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