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<blockquote data-quote="T3mpest" data-source="post: 6983199" data-attributes="member: 560148">lots of things.&nbsp; The thing to remember is that the port actually works by creating a mass of air inside the box&nbsp; that the speaker can excite that will resonate at the frequency you want.&nbsp; However, all that pressure has to come out the opening.&nbsp; If the port is small, you have a smaller mass of air moving which ultimately means less SPL.&nbsp; Once the air moves so much through the opening it will begin to get turbulent and no longer act as a proper port.&nbsp; You&#039;ll get what is called port compression.&nbsp; Basically the woofer will still move more, but since the port is already moving as much air as it can through an opening that size, your not getting any more SPL at that frequency like you should.&nbsp; So at higher volume levels when the woofer really begins to excite the port, you&#039;ll get a different frequency response since the port will stop adding output at the level it should.&nbsp; The second issue with this is that the air getting compressed will make a &quot;wooshing&quot; sound as it tries to leave the port.&nbsp; Since the box is right behind you that will be audible, so that&#039;s a no go.&nbsp; General rule is 12-16sq in. of port cubic foot of box room.&nbsp; You are at the bare minimum with no flaring on the port, it&#039;ll chuff for sure since your using a nice sub and high power.Listening to metal what&#039;s going on between 50-300hz is more inportant than 40 and down.&nbsp; If you tune high you will increase the top end a bit, but you also have a lot fo group delay in that region.&nbsp; Yeah, the kick drums will be louder (not necessarily realistic), but they will be out of sync with the rest of the sound and it often sounds sloppy and muddled.&nbsp; Imo for rock you want to tune low to get the group delay out of the region that it&#039;s audible on rock music.&nbsp; I&#039;ve done LOTS of boxes for people who like rock and they are usually tuned at 30hz or lower in some cases.&nbsp; It gives you a decently flat response and the group delay is low in magnitude as well as much lower in frequency.&nbsp; Plus when you play rap, you can tell it&#039;s ported as it crushes low notes in a way sealed boxes won&#039;t lol.&nbsp; Trying to tune at 40 for a rock music box is like trying to boost the 1 band eq that says &quot;treble&quot; on a stock stereo to get cymbals to sound good. Yes, part of the cymbal will be emphasized, but that doesn&#039;t make it realistic nor soudn good.3.15 at 35 is a decent compromise.&nbsp; IMO, I might start thinking about doing an external aero port.&nbsp; It won&#039;t look as pretty, but it&#039;ll sound alot better and it&#039;ll solve your space vs tuning issue.&nbsp; Plus you can keep chopping it down to try different tunings if you dont&#039; like how it sounds.</blockquote>

[QUOTE="T3mpest, post: 6983199, member: 560148"] lots of things. The thing to remember is that the port actually works by creating a mass of air inside the box that the speaker can excite that will resonate at the frequency you want. However, all that pressure has to come out the opening. If the port is small, you have a smaller mass of air moving which ultimately means less SPL. Once the air moves so much through the opening it will begin to get turbulent and no longer act as a proper port. You'll get what is called port compression. Basically the woofer will still move more, but since the port is already moving as much air as it can through an opening that size, your not getting any more SPL at that frequency like you should. So at higher volume levels when the woofer really begins to excite the port, you'll get a different frequency response since the port will stop adding output at the level it should. The second issue with this is that the air getting compressed will make a "wooshing" sound as it tries to leave the port. Since the box is right behind you that will be audible, so that's a no go. General rule is 12-16sq in. of port cubic foot of box room. You are at the bare minimum with no flaring on the port, it'll chuff for sure since your using a nice sub and high power. Listening to metal what's going on between 50-300hz is more inportant than 40 and down. If you tune high you will increase the top end a bit, but you also have a lot fo group delay in that region. Yeah, the kick drums will be louder (not necessarily realistic), but they will be out of sync with the rest of the sound and it often sounds sloppy and muddled. Imo for rock you want to tune low to get the group delay out of the region that it's audible on rock music. I've done LOTS of boxes for people who like rock and they are usually tuned at 30hz or lower in some cases. It gives you a decently flat response and the group delay is low in magnitude as well as much lower in frequency. Plus when you play rap, you can tell it's ported as it crushes low notes in a way sealed boxes won't lol. Trying to tune at 40 for a rock music box is like trying to boost the 1 band eq that says "treble" on a stock stereo to get cymbals to sound good. Yes, part of the cymbal will be emphasized, but that doesn't make it realistic nor soudn good. 3.15 at 35 is a decent compromise. IMO, I might start thinking about doing an external aero port. It won't look as pretty, but it'll sound alot better and it'll solve your space vs tuning issue. Plus you can keep chopping it down to try different tunings if you dont' like how it sounds. [/QUOTE]

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