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front or rear ported cabs.....opinions


ebenezer
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No difference. I believe at the range of the port the bass frequencies are omni directional, so the ports can actually be pointing in any direction.

The only difference for me was on tight stages where there was no room behind the cab for the port to "breath".

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the port only makes a sound around the tuning frequency. For most bass speakers that will be roughly 50Hz. The wavelengths down that low are roughly 6metres so moving the port 30cm round the back of the cab will make almost no difference to what you hear. Obviously if you were to jam the speaker hard against a wall and block the rear port then that would affect the output from the port but if it is more than the diameter of the port away from the wall you won't have a problem. You can use a rear ported cab with no worries

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[quote name='Lozz196' timestamp='1504387163' post='3364593']
On stage I don`t really notice the difference, but in a small rehearsal room I find rear-ported cabs seem a bit boomy
[/quote]That has nothing to do with the port location. For the most part the reason cabs are rear ported is because there isn't room for them on the front. There isn't room because the cab is small. Small cabs tend to accentuate the midbass, which is the source of boom. Boom may be more noticeable in smaller rooms.
[quote]What about side ported or bottom ported?[/quote]Radiation from ports is omni-directional. For that matter cone radiation in the lows and midbass is omni-directional as well. If you're able to stand behind behind your rig you'll notice that the highs are gone, and the midrange is muted, but the rest is unaffected.

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[quote name='fftc' timestamp='1504425008' post='3364683']
What about side ported or bottom ported?
[/quote]with side ported common sense works. it's no different from a rear ported cab. A bottom ported cab is going to hve some extra resistance imposed upon the port but the designer should have allowed for that in the design.I personally can't think o a commercial bass speaker with a bottom port.

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The theory is correct and fine but i've had front and rear ported cabs in the past and i could swear the front ported ones gave me more kick and less boom. Had and tried several from diferent brands in different gigs/rehearsalls (raised and away from walls, etc.) and i don't see myself owning a rear ported cab anywhere in the future. IMO and IME obviously.

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I'll give you an example to explain my POV, imagine a kick drum, stand behind it (next to the drummer) and listen to the sound. Now move to the other side, in front of the kick port, and listen to it. Isn't it different? There is some sound and tone comming out of the port, not just air, not just the tuning freqs. In practise it will add up to the rest of the cab's tone and make a (small but present) difference. ;)

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[quote name='Ghost_Bass' timestamp='1504626354' post='3366161']
I'll give you an example to explain my POV, imagine a kick drum, stand behind it (next to the drummer) and listen to the sound. Now move to the other side, in front of the kick port, and listen to it. Isn't it different? There is some sound and tone comming out of the port, not just air, not just the tuning freqs. In practise it will add up to the rest of the cab's tone and make a (small but present) difference. ;)
[/quote]

It sounds different when you stand on the other side because:

1. You're standing in a different part of the room so the reverb and standing waves are different.
2. A skin being hit by a beater sounds different to a skin resonating in sympathy.
3. A skin with a hole in it sounds different to a skin without a hole in it.

If a kick drum only made low frequency sound then your analogy would correlate somewhat but as lots of frequencies come off a kick drum and only the lowest are omnidirectional then it doesn't at all.

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[quote name='Ghost_Bass' timestamp='1504626354' post='3366161']
imagine a kick drum, stand behind it (next to the drummer) and listen to the sound. Now move to the other side, in front of the kick port, and listen to it. Isn't it different?
[/quote]It is, but not in the lows. This is a polar pattern of a typical large speaker:



The output pattern is 360 degrees to 80Hz. Port output is centered at the speaker tuning frequency, which generally runs between 40 and 50Hz. You will hear a difference with any source based on where you are, but it won't be in the lows.

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[quote name='alexclaber' timestamp='1504638301' post='3366307']
(..)
If a kick drum only made low frequency sound then your analogy would correlate somewhat but as lots of frequencies come off a kick drum and only the lowest are omnidirectional then it doesn't at all.
[/quote][quote name='Bill Fitzmaurice' timestamp='1504639660' post='3366318']
(...) You will hear a difference with any source based on where you are, but it won't be in the lows.
[/quote]

My point (even though i might have used a poor example) was that it isn't only lows that come out of the cab's port. When i stand in front of my cab i can hear (and feel) the "punch", there's something more added to the sound. With rear ported cabs i heard all the freqs but they lacked that [i]something extra[/i] that it's hard to explain without experiencing it.

EDIT:

A question for both of you. Mids and Highs are unidirectional in a bass cab right? But there's allways some bleed to the back of the cone. Isn't it possible that those freqs might reflect inside the cab and leave through the port along with the bass and that may translate in to [i]something more[/i]?
Don't give me text book answers please, i'm not a sound engineer, but i'm a very practical person and this makes scense to me.

Cheers

Edited by Ghost_Bass
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[quote name='Ghost_Bass' timestamp='1504690139' post='3366542']
Isn't it possible that those freqs might reflect inside the cab and leave through the port along with the bass and that may translate in to [i]something more[/i][/quote]It is possible, with a cab that's defective. One of the reasons why well designed and built cabs have internal damping is to prevent that. A few years back G-K brought out a line of cabs that were not damped, and poorly braced. They made the claim that they sounded better without damping. That claim was revealed as piffle when owners of them added bracing and damping and found they sounded much better after so doing. Not surprisingly Generation II of that line of G-K cabs were better braced and internally damped.

By the same token there have been rear ported cabs that placed the ports where midrange cone radiation could make its way directly out the port. That as well is a design defect.
[quote]
Don't give me text book answers please, i'm not a sound engineer, but i'm a very practical person and this makes scense to me
[/quote]Where the behavior of sound is concerned text book answers are a necessity, because what intuitively makes sense is usually wrong. Besides, you're a bass player. You're supposed to be the brains of the band. There is a different position for blokes who lack any clue as to how the gear they use to make a living with music works: guitar players. :gas:

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Bill and Alex make a living out if this and know what they're talking about, so we should defer to their knowledge. For what it's worth, I've played through front and rear ported cabs that I liked and front and rear ported cabs I didn't like. So quality must be due to the design/construction, rather than the type of cab. Imho, of course.

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[quote name='dannybuoy' timestamp='1504489056' post='3365211']
The Barefaced Retro 210 is designed to be used in either orientation, but if stacked vertically results in a bottom ported cab. I've always wondered if this would be problematic having read comments against placing rear ported cabs close to walls?
[/quote]

Any advice on this one Alex? Particularly if positioning a Retro 210 vertically on a carpeted floor?

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[quote name='Dan Dare' timestamp='1504709328' post='3366799']
Bill and Alex make a living out if this and know what they're talking about, so we should defer to their knowledge.
(...)
[/quote]

I take all of their info with much appreciation and have a huge respect for their knowledge, in fact i'm happly using a cab made (and not defective) by one of them. I just listen with my ears and not my eyes. I like to choose what i try and find is best for me, not what others tell me to choose.

I tried cabs from almost every high-end maker out there in all sorts of configurations (some owned by me, some in bass-bashes i usualy have with a small group of friends). I stand by my words, having the port aimed to the front gives something more to the sound, no mather how well designed/damped/braced anybody could build a cab.

It's just my opinion, fundamented by my experience. You're all free to disagree of course, you can show me proof that you're right but that won't make me wrong, i'll keep using what works best for my sound.

Cheers

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[quote name='Ghost_Bass' timestamp='1504710670' post='3366821']
I stand by my words, having the port aimed to the front gives something more to the sound
[/quote]Watch this, particularly from the 1:00 marker to the 5:10 marker, although almost every member here would benefit from watching all of it:

[media]http://www.youtube.com/watch?v=BYTlN6wjcvQ[/media]

Edited by Bill Fitzmaurice
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[quote name='Ghost_Bass' timestamp='1504710670' post='3366821']. . . . having the port aimed to the front gives something more to the sound. . . . [/quote]

With the port in front you get to feel the air coming out of the port.

I haven't heard the sound change between front and rear ports but the feel is different if you are standing close enough.

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[quote name='chris_b' timestamp='1504717454' post='3366877']
With the port in front you get to feel the air coming out of the port.

I haven't heard the sound change between front and rear ports but the feel is different if you are standing close enough.
[/quote]

Yes you're correct but i think there's even more to it than just that. With the port to the front it sounds more focused and punchy. The notes "breathe" more. The back ported cabs just throw me a wall of wooly bass that in some stages may become boomy. BTW, i use my cabs lifted to ear level and never in corners or backed against walls unless there's no other option available.

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[quote name='Ghost_Bass' timestamp='1504719277' post='3366893']
Yes you're correct but i think there's even more to it than just that. With the port to the front it sounds more focused and punchy. The notes "breathe" more. The back ported cabs just throw me a wall of wooly bass that in some stages may become boomy. BTW, i use my cabs lifted to ear level and never in corners or backed against walls unless there's no other option available.
[/quote]

The trouble is you are comparing chalk and cheese.

You aren't comparing speaker cabs with the same drivers in, they aren't the same shape, size and the ports are all different sizes and shapes. In addition unless you did your testing all in the same room with the speakers carefully placed at the same spot using the same bass and amp with the settings all identical it isn't really a fair test. Oh, and you'd have to put the speakers behind a screen and the assistant switching the speakers round wouldn't have to know which was which either, a double blind test.

What I'm hearing is that you prefer some forward ported cabs to some rear ported cabs. You are probably right but that isn't necessarily about the port. Most of us prefer the look of a traditionally ported cab (me included) they just look right. The reasons for putting the port on the back are usually to do with the restricted size of modern cabs. As someone has said you can't put a big port on a small baffle. Small cabs are only really practical with speakers with more powerful magnets to get the damping and they have characteristically different frequency responses. Maybe you just like big old cabs or underdamped responses. Nothing wrong with that it's what made the bass sounds we've all loved for years.

I guess the only reason for saying this is to help the next person looking to buy a cab. The advice is that you should try them out, see how they sound, don't worry about where the port is. Buy the one that sounds right.

Always be sceptical of experts unless they offer evidence, which people have, but science does give you a way of deciding right from wrong and a lot of people here like the technical details. In this case the science is unequivocal, the placing of ports isn't going to make a difference unless someone has screwed up. There are better things to worry about, like the size of the ports.......

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[quote name='Kevin Dean' timestamp='1504723659' post='3366923']
If I've had my rig in front of a drummer Ive had complaints when using rear ported cabs that the lows were too loud muddy sounding .
[/quote]Look at the polar chart I posted. Of course it's muddy when the cab is in front of him, all he can hear is what's below at best 300Hz. To his side is better, but if he's going to hear the entire bandwidth you must either be in his monitor or you need two cabs, stacked vertically, with the lower cab aimed at him, the upper cab aimed at you.
The science of audio always works, whether you believe in it or not. The problem when you don't learn the science is that when issues arise you won't know what causes them, so you can't know how to fix them.

Edited by Bill Fitzmaurice
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