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Difference between Front and Rear Ported!

#21
Bill F: (or anyone) Here's a semi-related question. Where would be the optimum port placement, say on a small 1x15, whose front baffle is just big enough (18"x18") to accommodate the driver?

(4" round port tube)
A; Rear....Directly behind the magnet.

B; Rear....Towards a corner, but behind the cone.

C; Side....Either in the center of a side wall, or more towards the top or bottom of a side wall.

What's best, and why?
 
#23
lbwdog said:
Bill F: (or anyone) Here's a semi-related question. Where would be the optimum port placement, say on a small 1x15, whose front baffle is just big enough (18"x18") to accommodate the driver?

(4" round port tube)
A; Rear....Directly behind the magnet.

B; Rear....Towards a corner, but behind the cone.

C; Side....Either in the center of a side wall, or more towards the top or bottom of a side wall.

What's best, and why?
Click to expand...

billfitzmaurice said:
Omni-directional port output is why a port can be placed anywhere except directly behind the cone, as that will allow midrange to go through the port and that can cause problems with reflected midrange off a rear wall.
Click to expand...


Really really not A.
 
#25
I have a 3 speaker system for the television, 2 satellites and a sub. You can stand in front of the satellite speaker and swear the bass was coming out of it b/c your brain will assign the low frequencies to the speaker that has the harmonics. That doesn't have much to do with this discussion except that your brain plays tricks on you when you're trying to locate very low frequency sources.
 
#26
I like front porting since you can feel the air being pushed by my
WORLD-DOMINATING BASS POWER. :D

I mostly play in smaller rooms and it is pretty cool feeling the air blast out of my Carvin combo. Many times I am smashed up against a wall also.

Front porting wins for me.
 
#27
lbwdog said:
Bill F: (or anyone) Here's a semi-related question. Where would be the optimum port placement, say on a small 1x15, whose front baffle is just big enough (18"x18") to accommodate the driver?

(4" round port tube)
A; Rear....Directly behind the magnet.
Click to expand...
Worst possible place, and probably won't fit anyway unless the cab is very deep.
B; Rear....Towards a corner, but behind the cone.
Click to expand...
Second worst possible place.

C; Side....Either in the center of a side wall, or more towards the top or bottom of a side wall.
Click to expand...
OK, but the best option is four small triangular ports at each corner of the baffle. Then they also add stiffening to the baffle and sides.
 
#28
BassistForHire said:
..... your brain plays tricks on you when you're trying to locate very low frequency sources.
Click to expand...

Very true. Sometimes you can even locate low frequencies when they're not even present! For example, ever notice how you can identify a deep voice over the phone even though the speaker in the earpiece is reproducing nothing below 500Hz? Your brain is programmed to fill in the blanks.
 
#30
I have spent decades behind the Neve and SSL... and dabbled in Mastering for some time..:D
have just a few credits.. I know what i can hear...
I sometimes laugh at some folks here when they say what they say is fact.. when they have no practical hands on or ears on experience in an actual scenario that they claim they know all about .. simply because they read an article about it somewhere... sometime... on a forum written by someone else :rollno:


BassIan said:
Nobody is questioning whether you can locate the cab or not. So can I. However, you and I are not locating it because of what you hear at any frequency affected by porting. We are hearing other artifacts that *are* directional.

An understanding of the technical side of equipment makes it easier to enjoy music. Less time fumbling over why something doesn't work, more time playing. My job is engineering (nit-picking details), and it just happens to make the music side easier too.
Click to expand...
 
#31
I have had some issues with rear ported cabs .. mostly on larger big stages... not my thing...
I really like the idea of the Fearful 15.6 front ported thing folks are doing on here...
And i really dislike horn loaded cabs.. they always sound like a megaphone to me.... i like for lack of a better word,direct radiating speakers all paper if possible...


Blues Cat said:
I've had a terrible time dealing with rear ported cabs. Too much variation in sound from room to room.
Click to expand...
 
#34
svtb15 said:
I have spent decades behind the Neve and SSL... and dabbled in Mastering for some time..:D
have just a few credits.. I know what i can hear...
I sometimes laugh at some folks here when they say what they say is fact.. when they have no practical hands on or ears on experience in an actual scenario that they claim they know all about .. simply because they read an article about it somewhere... sometime... on a forum written by someone else :rollno:
Click to expand...
well i have plenty of experience, kirk, and when i do large gigs with subs that are hidden, i'll always go out in foh if there's another band on the bill, and i always have to ask where they are because i have absolutely no idea where they're located by listening. granted, when you get up close on one you can tell just because it's making you have to go to the bathroom ;) but 5-10 feet out and i have no clue. try it next time.

it's pretty well agreed upon by cab makers that port location is immaterial. at least the high end ones.
 
#36
svtb15 said:
I have spent decades behind the Neve and SSL... and dabbled in Mastering for some time..:D
have just a few credits.. I know what i can hear...
I sometimes laugh at some folks here when they say what they say is fact.. when they have no practical hands on or ears on experience in an actual scenario that they claim they know all about .. simply because they read an article about it somewhere... sometime... on a forum written by someone else :rollno:
Click to expand...

You sure do know a lot about my experience and background. Years behind a console may give you experience, but that still doesn't make you right. Who are you implying I am parroting, and what is my background, if you know so much?

This is more than enough for me to step out. Next time, an open mind and some tact might allow both of us to learn something.
 
#37
Mr. Foxen said:
Isn't lots of small ports bad because the airflow is more restricted and turbulent? Or are they made a little bigger area wise to compensate?
Click to expand...
Turbulence happens when the ports are very long and very narrow. Multiple small ports don't suffer any more turbulence than one larger one.
I have spent decades behind the Neve and SSL... and dabbled in Mastering for some time..
have just a few credits.. I know what i can hear...
Click to expand...
Your mixing skills and experience have no bearing on the discussion. As for what you 'know' that you hear as a recording engineer, an acoustical engineer knows why you hear it. As a parallel, it's one thing to be a driver and have the skills to drive a car. It's something else entirely to have the skills to design and build said car. Even a million miles of driving experience doesn't make you Enzo Ferrari.
 

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