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Post by lovedoctor on May 20, 2010 10:01:37 GMT -7
Has anyone had any experience directly comparing these two companies' IB specific drivers? I've already poured through this forum comparing costs/displacement of 4 AE 15s vs. 2 FI 18s, with the dollars per liter being at least roughly comparable.
My question is primarily concerned with the rather subjective judgment of sound clarity (e.g. less harmonic distortion, flatter response with less need for EQ). The AE drivers appear to have a slight edge with a lower Fs and Qtc of 0.7. But in real world application, do those T/S parameters make an audible difference?
Of course, actual experience with both drivers and one set of ears is preferable, but I'll take hearsay, rumors, and outright lies as well.
Thanks!
Oh, my tentative plan for my ~2000ft3 media room is a manifold of either 4 AE 15s or 2 Fi 18s, powered by a Dayton 500W plate amp, with an eD EQ.2 (total of 3 parametric EQ channels and an SSF), RatShack SPL meter with REW software.
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Post by pmcneil on May 20, 2010 12:13:54 GMT -7
There isn't much discussion around here about distortion, though obviously this is a bad thing. Perhaps because it is not a measured variable available to the community. Why not? Ask the manufacturer's (suppliers), since this is a measurable parameter, no?
AE and DIY emphasize that they utilize low distortion designs. Do they?
I took DIY's word for it, and am happy with their DPL-15s...but cannot offer a comparison with the competition.
We desperately need an IB reviewer on this site (where else, but here, after all). He/she would agree to objectively (and subjectively) review (and, with time and experience, compare) drivers from all relevant manufacturers willing to supply them for review purposes. But who would volunteer for this job (must be a person of great stature on the site) and would the manufacturers participate?
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Post by ThomasW on May 20, 2010 12:44:46 GMT -7
People interested in test results should buy one of each driver they're curious about, next send them off to Klippel for testing. IIRC they do it for ~$250 per driver.... |
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Post by chrisbee on May 20, 2010 12:46:50 GMT -7
There are so many variables with IBs that simple distortion comparisons are not as easy as with box subs. Life will be considerably simplified by the reviewer already having an existing IB. Only one new set of drivers will be necessary to make a subjective (or objective) comparison. My own experience is that more drivers will lower distortion quite noticeably. Perhaps displacement matching is also necessary to make fair comparisons? 4 AEIB15s = 2 Fi IB318s? Perhaps cone area is far more important than displacement when the drivers are hardly ever moving even at high levels? A solid structure makes a lot of difference too. Otherwise structural resonances produce their own harmonics. Quite possibly with their own delay superimposed on the IB's own output. A concrete cellar will have a completely different sonic and distortion signature to an attic with all "lightweight" surfaces. An array will behave very differently to a manifold. Manifolds can be undersized and of different physical arrangements. There is no "standard" IB. Total Vas rears its ugly head in many IB applications. (but not all) Enclosure damping, size and geometry matters. As does AV/HT room size, shape, openness to the rest of the house and damping. Power available? Amp quality? EQ? Bass boost to match the responses? Room modes? Source? REW can measure distortion. I have listed some figures of my own system in my blog. I found that VLF distortion went skywards at higher SPLs as a result of my flimsy attic structure and undersized enclosure. I could not run at very high levels at VLFs without opening the access doors to silence them. (yet another variable) To sum up: Are you feeling lucky?  |
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Post by pmcneil on May 20, 2010 15:26:22 GMT -7
No, Chrisbee, I'm not, feeling lucky, at the moment!  And as for paying for testing...the question us consumers have is why don't the sellers/manufacturers of the product cover this expense? Well, because we, the buying public, don't demand it. We look only for 'swept volume' numbers. Maybe distortion does not matter, at low frequencies, for us humans. How could discrimination at low frequencies have been helpful, in finding prey or avoiding predators? Mids and highs, yes, very helpful...buy hard to localize lows...hmmmm... |
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Post by chrisbee on May 20, 2010 23:57:59 GMT -7
Maybe distortion does not matter, at low frequencies, for us humans. How could discrimination at low frequencies have been helpful, in finding prey or avoiding predators? Mids and highs, yes, very helpful...buy hard to localize lows...hmmmm... I beg to disagree. Low frequency sounds are rarely pure LF fundamental. Most sounds have a harmonic content which help us to identify the source. We can separate a high waterfall from a charging rhino. (or T Rex) We can differentiate the war drums from the next village from our panicking horses in the corral. The harmonics help us to confirm direction. In modern times we have traffic, aircraft overhead and car subwoofers, car doors slamming and railways. Low frequencies are associated with fear, an adrenaline rush and flight from stampeding animals. If we can easily identify the source our arousal may be reduced but it can still lead to a strong mood change. It may be pleasure at a rock concert or anger at the neighbour's Harley. Or his parent's late night party. Low distortion is vital to quickly identifying a bass source. Something we take for granted in real life. It lowers out fear levels so still has real survival value. We don't get run over by the Harley while fleeing blindly from T Rex. The reproduction of low frequency sounds with low distortion is crucial to a sense of greater realism. We want to separate the bass drum from the bass guitar in our rock music. We want to recognise shells falling in Saving Private Ryan from the sounds of tanks and gunfire. We want to clearly hear the advancing tanks changing gear and struggling up inclines and over fallen debris. We would be very disappointed if everything sounded exactly the same. Doubling the number of drivers in my IB brought an instant sense of realism which was completely unexpected. The battering ram on the gates of the keep in LOTR was suddenly a brutal eye opener! Organ music suddenly became a mixture of unbelievable clarity allied with immense weight. The subtlety of the way the huge pipes speak was effortlessly portrayed in comparison with only four 15" drivers. Most people would think four, low distortion, 15" drivers were easily enough for the task. So did I until I added four more. The sounds hadn't really become any louder. The low frequency extension had actually been reduced by a couple of Hz. The extra drivers had brought much lower distortion. Which made things sound much more real. Leading edge, sustain and decay were far more clearly exposed. If you go to an AV show you will hear countless subwoofers all sounding exactly the same. It doesn't matter if it's a karate kick or a gun being fired on the system screen. A bass guitar or a big drum in a jungle film? Nah. Luckily the screen shows you what is happening. The subwoofer certainly can't! Every LFE sound is identical. Realism is completely absent. The first time I attended a local AV show I immediately recognised the racket. I was listening to the subwoofer packaging being beaten with a stick! Any packaging and any subwoofer would do. Why spend more? The money didn't seem to make any difference. Most subs produce massive distortion as the frequency falls. Mud, to you and me. Muffled to you and me. Soft to you and me. Ya want loud buddy? They can do loud! But no leading edge and no decay. Wompa-wompa-wompa-wompa. Is it a charging rhino? No it's the plane!  |
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tomw
New Member
Posts: 39
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Post by tomw on May 21, 2010 7:51:57 GMT -7
Chris,
Well said, keep it up.
Is there an organ DVD or Cd you would recomend for a newby?
Thanks for all your posts,
Tomw
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Post by chrisbee on May 21, 2010 8:28:15 GMT -7
Hi tomw My favourites are listed here: ibsubwoofer.blogspot.com/2007/11/ib-performanceon-organ-music.htmlAll of these have strong bass and are well recorded according to my ears and equipment. The "Tzar Of Instruments" has an excellent selection of tuneful pieces. Most of the pieces are "accessible" to the non-organ fanatic. Check out YouTube for a great many organ recitals to see what you like. (or not) Sound quality on these videos varies enormously. Just as it does on CD and vinyl. |
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Post by jman on May 21, 2010 11:00:49 GMT -7
Maybe distortion does not matter, at low frequencies, for us humans. How could discrimination at low frequencies have been helpful, in finding prey or avoiding predators? Mids and highs, yes, very helpful...buy hard to localize lows...hmmmm... There are 2 kinds of distortion- harmonic - the signal has frequency "x", say 15hz. With harmonic distortion you get 15hz, and then 30, 45, 60 (2nd, 3rd, 4th order harmonics, and so on). The even-order are the same pitch but a higher octave. So they aren't horrible sounding but they do blur or even mask the real, or fundamental signal. Odd-order are a different pitch so they cause more "damage" to the presentation IMD or intermodulation distortion- this is the really nasty stuff. These are frequencies created between 2 real signals in the source. They have nothing to do with either original signal and sound horrible. Most of the bozos on AVS forum, still can't believe that 10 or 15hz are audible and sound different from 20 or 25hz. But nothing else sounds like 10 or 15hz once you hear them on an IB without the gobs of harmonic distortion in standard box/cylinder subs. |
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Post by pmcneil on May 21, 2010 12:09:13 GMT -7
OK, I've ordered a couple of the Chrisbee suggested organ CDs, but remain unconvinced by the T Rex and Harley argument!
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Post by pmcneil on May 21, 2010 12:24:58 GMT -7
Please see regarding hearing acuity as a function of frequency the following WiKi article and see the figure below....http://en.wikipedia.org/wiki/Equal-loudness_contour Attachments:
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Post by chrisbee on May 21, 2010 12:55:30 GMT -7
Please see regarding hearing acuity as a function of frequency the following WiKi article and see the figure below....http://en.wikipedia.org/wiki/Equal-loudness_contour I rest my case. Masking of the fundamental is all too commonplace. A completely wrong harmonic structure is almost universal to both subwoofers and speakers. The majority have no transparency to the underlying fundamental. The IB does. The IB can clearly expose the shivering, breathy awakening of the great flue pipes, their sustain and equally gentle decay. Almost at the limit of human audibility each pipe sounds different and speaks in a different way. Until you have heard the distinct timbre of the great pipes exposed in all their subtle and gorgeous detail you will not be convinced. |
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Post by pmcneil on May 21, 2010 16:26:52 GMT -7
What the curve shows is that for a constant human response ('phon'), far more energy is required in the bass region than in the midrange. More is also required in the extreme treble. And, there is a far smaller range of responsiveness (ranging from imperceptible to unbearable) in the bass region.
The curve explains why a 'loudness' function has been so popular, and why we bass heads spend so much time and money on increasing bass output!
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Post by chrisbee on May 21, 2010 22:36:05 GMT -7
The Equal Loudness curves (formerly Fletcher Munsen) do not directly explain the astonishing superiority of the IB over other subwoofers. My room supports a naturally rising response into the infrasonic. This is also true of my other subs to an even greater degree. Only the IB provides realistic, low distortion reproduction of low frequencies.
This is hardly surprising since it has so many driver cones moving minuscule distances well within the most linear part of the stroke. The mutual acoustic coupling of so many drivers reduces the necessary cone excursion to the almost invisible at normal listening levels. Only a finger placed gently on the outer roll suspension suggests vibration.
No doubt the light workload placed on each cone reduces cone breakup. Which must be common to single driver subwoofers relying on massive excursions to achieve any output at low frequencies.
The very large cone area provides a better matching impedance to the air with falling frequency. The air is gently moved by the large cone surface area rather than being stirred violently by a thrashing long-throw cone. The extra excursion available from the IB drivers merely provides the headroom required to reproduce very high SPLs at very low frequencies. I would still trade cone area for extreme displacement once the driver safety level is reached.
There are no boxy colourations with the IB. No port noise or port inertia to spoil the show.
No violent phase effects around the tuning point to drain power from the amplifier. No rising voice coil temperature effects since the IB is such an easy load. There is no rapid roll-off beyond the tuning point.
Even if one were to keep adding box subwoofers until one matched an IB for cone area (or total displacement) they still could not match the IB for sound quality. Colouration would probably be cumulative and no stacked subwoofer assembly can play lower than a single example. Few subwoofers can match the frequency extension of the IB.
I imagine the law of diminishing returns applies equally to bass heads. Each new bass/SPL fix produces a given level of stimulation. Closely followed by a reduction in hormone output resulting in eventual boredom. The majority of bass heads are probably young. This age group is well known for extreme reactions to stimulus and high levels of risk taking. They may need a coarser bass fodder than those who have learned to appreciate simple reality reproduced in very high quality. I am generalising, of course. ;D
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Post by jman on May 22, 2010 0:06:41 GMT -7
The hardest thing about having an IB is not sounding like an informercial when telling people about it.
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Post by chrisbee on May 22, 2010 3:10:23 GMT -7
The hardest thing about having an IB is not sounding like an informercial when telling people about it. You've noticed? ;D The biggest negative is convincing other halves that it often requires holes to be cut in the happy home.  |
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Post by ThomasW on May 22, 2010 7:23:04 GMT -7
The Equal Loudness curves (formerly Fletcher Munsen) do not directly explain the astonishing superiority of the IB over other subwoofers. Available to those with 'large' (high displacement) IB subs is the experience of visceral effects, these are a function of tactile perception. Through our bodies hard and soft tissues we're able to experience frequencies from 3Hz-3kHz. Paul W has posted about the effects of his 18-15" driver IB playing the movie "Blackhawk Down". And startled people were when the helicopter rotor 'sounds' caused the sofa to move across the concrete floor of his listening room. The hardest thing about having an IB is not sounding like an informercial when telling people about it. Yeap that's always been an issue. Unless experienced hands-on it's difficult to comprehend how different an IB sub is from other types of subs... |
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Post by cmryan821 on May 22, 2010 8:21:41 GMT -7
The hardest thing about having an IB is not sounding like an informercial when telling people about it. Dear Lord that is so true. I've had to stop myself a few times. |
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Post by pmcneil on May 22, 2010 10:16:57 GMT -7
Hey, guys, no need to 'stop yourself' in talking about the virtues of an IB. There is nothing else like an IB, that I know of.
What many (can I say most) 'audiophiles' don't understand, but would be astounded to hear, is what a difference an IB makes. Yes, the extension an IB provides is something that most of us have not experienced. When the typical audiophile talks about 'fast' bass, I now think I know what they mean: they are referring to bass without the box (or, should I say, since they have a box, with minimal box), and its coloration.
What, besides extension, does the IB do: it adds a remarkable increase in the clarity and transparency of the sound, and not just in the bass, but in the highs and midrange of the fronts and surrounds as well. Last night, for example, I was listening to the HBO series, 'Treme', which features some great jazz, reproduced beautifully in 5.1. It was a revelation! A three dimensional recreation of every instrument that got closer to the real thing than I ever imagined possible. All I added was an IB. I never got that with three expensive boxes.
And, by the way, the 'Equal Loudness Curve' was not posted in explanation of the IB's superior sound. But, in response to previous submissions...please see them!
And, yes, the problem for most of us who want great sound is that (except in my case where I already had one...the former site of an in wall air conditioner and a door to an attic storage space) a hole must be made in a wall (or the floor, or ceiling), and someone might object to that, on ascetic grounds. But, perhaps even more importantly, in my case and I suspect many others, there is the problem of initiating the act of cutting the hole, etc., which in many cases must be undertaken in complete ignorance of, and experience with, such a procedure. Talk about fear and trepidation raising its ugly head!
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Post by pmcneil on May 22, 2010 11:08:44 GMT -7
lovedoctor, did we get off topic?!
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