i am in the midst of contemplating building a new enclosure but before i do there are a couple things i need to get straight about vented enclosures..
1. somewhere i was reading that the internal pressure of a vented box can be greater than a sealed box at certain frequencies.. ie tuned freq..
is this true...?
2. suppose a high subsonic filtered sub signal was playing into a vented box with a low tuning frequency and high mach/port air speed @ tuned freq. would one have to worry as much about the high mach speed?
3. bracing is key in an enclosure, (true) but how much of a difference (ie. losses) is there between an unbraced and braced vented box playing at a moderately low volumes...?
1. somewhere i was reading that the internal pressure of a vented box can be greater than a sealed box at certain frequencies.. ie tuned freq..
is this true...?
2. suppose a high subsonic filtered sub signal was playing into a vented box with a low tuning frequency and high mach/port air speed @ tuned freq. would one have to worry as much about the high mach speed?
3. bracing is key in an enclosure, (true) but how much of a difference (ie. losses) is there between an unbraced and braced vented box playing at a moderately low volumes...?
1.hmmm i havent heard of this.
at Fb the system is in resonance for sure,whether this means its highpressure or not i dont know.
2.Do you mean a high amplitude low frequency tone below Fb is played?
check winisd/subwoofer simulator to see the vent airspeed graph
it tends to peak near Fb depending on box and speaker.
keep the peak airspeed below 5% of speed of sound.some ppl go even lower to completely avoid this.<distortion and compression>
3.losses and resonances colouration etc,which you dont want.to see a good example of it
www.geocities.com/adrian_mack/homepage.html
i have just got a book out of the library about ports,bracing,and distortions..il go get it sometime and quote somthing from it.
use 25mm if you can for moderate sized subs eg 12inchers and the larger the box the more bracing.for my 175L i used only 18mm MDf which isnt good,and i put one horizontal crossbrace below driver front to back,and another that joined onto that that was vertical.
sand is good too 😛
at Fb the system is in resonance for sure,whether this means its highpressure or not i dont know.
2.Do you mean a high amplitude low frequency tone below Fb is played?
check winisd/subwoofer simulator to see the vent airspeed graph
it tends to peak near Fb depending on box and speaker.
keep the peak airspeed below 5% of speed of sound.some ppl go even lower to completely avoid this.<distortion and compression>
3.losses and resonances colouration etc,which you dont want.to see a good example of it
www.geocities.com/adrian_mack/homepage.html
i have just got a book out of the library about ports,bracing,and distortions..il go get it sometime and quote somthing from it.
use 25mm if you can for moderate sized subs eg 12inchers and the larger the box the more bracing.for my 175L i used only 18mm MDf which isnt good,and i put one horizontal crossbrace below driver front to back,and another that joined onto that that was vertical.
sand is good too 😛
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