I believe an OB reaching really low can be constructed, that's not the point.
But does it sound "better" in that lowest octave? Are the needed dimensions and air displacement capabilities worth the effort in a normal listening room?
Pano, you said the best bass you heard was from a bass reflex....
But does it sound "better" in that lowest octave? Are the needed dimensions and air displacement capabilities worth the effort in a normal listening room?
Pano, you said the best bass you heard was from a bass reflex....
I guess so, but in that case you might as well mount the woofers in the room wall and let the backs radiate into the other room; you'd get excellent bass in both rooms!
Well, that alone says a lot.
I guess that's pretty much the same as the last octave for the fullrangers is 6khz-12khz ? 😉
Soon in a theater near you:
Minimalism. Or how to live with less than 4 octaves. 😛
If you did that, you would completely separate the front and back waves.
Thus, there would be zero cancellation, and the native response of the driver would dictate.
In the world of the OB fanatic, they believe allowing the front and back wave to cancel each other out, to some degree or another, actually results in superior bass, verses a system designed with a proper enclosure. This has puzzled me for quite some time. Or should I say I am quite baffled ? 🙂
No, no, no! No IB cheating!
I have both 4x8' wood sheet and 18FH500, if that is accepted by OB afficionados here, just let me know where to make the hole, and i'll compare it with my JL's in sealed box.
Already tried the 18FH500 in a sealed box and that was not convincing:
http://www.diyaudio.com/forums/subw...b-woofers-comparison-faital-v-s-jl-audio.html
But maybe it will in OB ?
Then if it's a question of QUALITY, the only proper way to compare sealed box V.S. OB would be to blind test them.
I doubt anything below 40hz would be easy to spot at low/moderate volume, and at higher volume when distortion/mechanical noise could appear i sure wouldn't bet on the OB...
Other possible test would be to use the same driver. I don't have a pair of 18FH500 but i have a pair of 12W6v3, would it be a good OB contender ?
EDIT: even better with Qts 0.67 ? 12W0v3, got a pair as well.
I doubt anything below 40hz would be easy to spot at low/moderate volume, and at higher volume when distortion/mechanical noise could appear i sure wouldn't bet on the OB...
Other possible test would be to use the same driver. I don't have a pair of 18FH500 but i have a pair of 12W6v3, would it be a good OB contender ?
EDIT: even better with Qts 0.67 ? 12W0v3, got a pair as well.
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18FH500
Jon, that driver~~~ Faital Pro 18FH500, does like like to see a sealed enclosure. What it does like, is a 9 cubic footer, tuned to 35Hz. No whimpy port size either; make it big !!
Yeah, play the Jim Keltner drum solo from Sheffield through an OB system, and then play it on something with real bass. Get back to us on that, okay ?
Jon, that driver~~~ Faital Pro 18FH500, does like like to see a sealed enclosure. What it does like, is a 9 cubic footer, tuned to 35Hz. No whimpy port size either; make it big !!
Yeah, play the Jim Keltner drum solo from Sheffield through an OB system, and then play it on something with real bass. Get back to us on that, okay ?
I wish, but i won't Scott. 9 cu.ft. is impossible for my project and i cannot even consider it. Anyway, already heard 21's in 200 liters sealed box and i heard the same flaws (compared to my W7's)... I already moved on and forgot 3-way to go 4-way and will use the 18FH500 (or 15PR400) for 80-500hz... In OB/nude... Hence this thread 🙂
FYI: i consider the 18FH500 very surprising in ''nude'' (tested it fixed on the top of said sealed box), but was testing it mostly 80-500hz, not for the first 2 octaves.
...ok ?
So the real quest here is to annihilate the 20-30hz region, is that it ?
Let's put that damn first octave on diet! 😉
The bass is better because it's thinnier! That's the secret.
How big is 80Hz ?
Just how big is 80Hz ?
1140
_____
80 ........... = 14.25 feet.
So, let that wrap around your baffle for a while !!
peace out... I'm gone to do some listening 🙂
(to some real bass)
Just how big is 80Hz ?
1140
_____
80 ........... = 14.25 feet.
So, let that wrap around your baffle for a while !!
peace out... I'm gone to do some listening 🙂
(to some real bass)
Attachments
Yup, let's forget the first octave OB thing for a while... i'd be curious to have your comments on the naked/nude/baffle-less concept (compared to OB) ?
I did some test and was surprised by the quality of the midbass (say 100-300hz) compared to any ported or sealed box, but is the baffle merit only lies in the bass boost... or something else as well ?
In other words: if you have a subwoofer... There is basically no need for any baffle as long as you get enough low-end to reach said subwoofer... Thus, baffle-less would be the way to go in that case ?
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I'm just thinking out loud here, but it's quite funny to see 2 COMPLETE OPPOSITE ways of doing things:
On one side the baffle-less concept, and on another side the horn concept which is essentially the most extreme of baffle possible.
One completely naked and one completely ''clothed''!
And yet, both concepts have their convinced fans claiming their solutions works very well!
I did some test and was surprised by the quality of the midbass (say 100-300hz) compared to any ported or sealed box, but is the baffle merit only lies in the bass boost... or something else as well ?
In other words: if you have a subwoofer... There is basically no need for any baffle as long as you get enough low-end to reach said subwoofer... Thus, baffle-less would be the way to go in that case ?
----------------
I'm just thinking out loud here, but it's quite funny to see 2 COMPLETE OPPOSITE ways of doing things:
On one side the baffle-less concept, and on another side the horn concept which is essentially the most extreme of baffle possible.
One completely naked and one completely ''clothed''!
And yet, both concepts have their convinced fans claiming their solutions works very well!
Yes, the Onken W cabinet. 2x Altec 416 woofers in a large box with sand filled walls. Small ports of unequal size. Best, cleanest, most impressively realistic bass I've ever heard. Did not sound like a speaker at all, which was quite surprising and made it memorable.
And guess what, it didn't have an F3 of 20Hz. 😛
That's my point. Dogged pursuit of some number, just because you read it somewhere, is not the path to good bass. Of course there are several people posting here who believe that it is - all I can do is shake my head wonder if they'll ever learn. All I can do is try to point out that number chasing is a distraction.
My experience is that Fs must be significantly lower with OB, having built a few, than the desired low output range; generally 20-25 Hz.
Forty years ago I built an OB that when looked at from above was an” L”. The short leg rested against the wall at an angle, with the drivers on the wide face facing the listener. Drivers were B139s.
The front and back faces were separated by 3 inches and the space filled with fine dry sand (after positioning!). The bass went low.
Forty years ago I built an OB that when looked at from above was an” L”. The short leg rested against the wall at an angle, with the drivers on the wide face facing the listener. Drivers were B139s.
The front and back faces were separated by 3 inches and the space filled with fine dry sand (after positioning!). The bass went low.
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" To strain out a gnat ........" Isn't the velocity of propagation of sound = 1126 feet/second ?
C.M
Bingo! Directivity control just above room modes minimizes first reflections from room boundaries. Wide open baffles loose dipole pattern too early.
It's 1130, which is the figure i used to use, all the time. Then somebody told me I was wrong. At that time I looked it up, and it was closer to 1140. But now I look it up and it's back to 1130. I learned it at 1130, so there it stays, frm now on.
1130 divided by 80Hz = 14.125 feet. That's how big 80Hz is. Thus, on a simple plane type baffle, say of a 24 inch width, and which is open to the back, the 80Hz note does not get a chance to develop to it's full potential.
It wraps around REAL FAST and cancels out.
Come on let's not be vague in order to squeeze out more performance from OB's than physically possible: it depends on baffle width when canceling starts, and by a bit more than a few dB per octave. I'd say 6 dB per octave below Fs and another 6 dB per octave because of canceling.
The curve drops away by at least 12 dB / octave in theory.
Practically, with proper placement and room gain into the mix you might reduce the loss just a bit.
The curve drops away by at least 12 dB / octave in theory.
Practically, with proper placement and room gain into the mix you might reduce the loss just a bit.