tomw
New Member
Posts: 39
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Post by tomw on May 22, 2010 11:26:03 GMT -7
Thanks Chris,
After going to your blog I remember reading it a few years ago. It sounds like a well written sales brochure for organ music. Excellent! Lots of good stuff on there.
I'll order up one and have a listen.
Tomw
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Post by ThomasW on May 22, 2010 11:53:36 GMT -7
lovedoctor, did we get off topic?! He hasn't logged onto the forum since starting this thread. |
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Post by pmcneil on May 22, 2010 12:23:42 GMT -7
Oh my, it's all hot air!
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Post by pmcneil on May 22, 2010 12:31:06 GMT -7
Actually, no it is not 'hot air', it's actually very accurate, what I'm getting now... ;D
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Post by lovedoctor on May 25, 2010 16:44:50 GMT -7
No, no. Still here. The wife just had a baby, so you know, not much else going on...
Thank you for the replies, although they may have been to other questions. Glad I could stimulate some good conversation?
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Post by moonfly on Oct 18, 2010 14:16:35 GMT -7
did the OP make a decision in the end?
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Post by maxserg on Oct 18, 2010 19:31:12 GMT -7
Anyway Peoples fear IB because they don't understand(i'm not talking about measurements techniques) the laws of how is built a house. But if you take the time to understand how is built a house and "all of it's secrets" it is so easy to modify your environment to reach the correct setup, man this is a party, you should not worry (if you know what you're doing) to make a sub that is the best and cheapest way to get the "real" bass, and this with minimal effort AND MONEY you could invest.
Here the laws of physics tell you the truth
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Post by lovedoctor on Oct 19, 2010 14:56:24 GMT -7
did the OP make a decision in the end? Nope. Other projects took center stage, although this may be revisited again next summer. Somewhere in the Drivers section of the CoIB forum there is a model of 4 AEs vs 2 Fis. WinISD says the AEs produce a slightly flatter curve especially near 20Hz, but the Fis have the edge in total output in the audible range. Of course, this is a program's best guess assuming an infinitely large room which rarely translates well to reality. |
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Post by chrisbee on Oct 19, 2010 22:42:22 GMT -7
did the OP make a decision in the end? Nope. Other projects took center stage, although this may be revisited again next summer. Somewhere in the Drivers section of the CoIB forum there is a model of 4 AEs vs 2 Fis. WinISD says the AEs produce a slightly flatter curve especially near 20Hz, but the Fis have the edge in total output in the audible range. Of course, this is a program's best guess assuming an infinitely large room which rarely translates well to reality. I can confirm that the AEIB15s FR is amazingly flat in my anything but infinitely large room: Typical FR: Listening position: No BFD: 1/3 octave smoothing.  |
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Post by newbieaudio on Dec 2, 2010 19:39:26 GMT -7
Chrisbee said: "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. " While the cult members seem to agree that you don't need (8) 15"s to provide adequate deep bass output for music, your comment does suggest using (8) 15s to improve the quality of music. By doubling your 15s to (8), you're cutting your travel by 1/2. When I've looked at Bl and suspension curves (Klippel), non-linear distortion increases with displacement, and continues to degrade with larger displacements. It appears that going to 8 drivers may be worthwhile for the distortion reduction alone. Since I'm not a head-banger, or concerned about HT extreme audio performance, I'm now leaning toward going to 8 15s for the improvement in music quality - as Chrisbee said: "...made things sound much more real. Leading edge, sustain and decay were far more clearly exposed." Any thoughts? Thanks, Dave |
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Post by chrisbee on Dec 2, 2010 23:52:24 GMT -7
While the cult members seem to agree that you don't need (8) 15"s to provide adequate deep bass output for music, your comment does suggest using (8) 15s to improve the quality of music. By doubling your 15s to (8), you're cutting your travel by 1/2. When I've looked at Bl and suspension curves (Klippel), non-linear distortion increases with displacement, and continues to degrade with larger displacements. It appears that going to 8 drivers may be worthwhile for the distortion reduction alone. Any thoughts? Hi Dave Are audio newbies supposed to know anything about Bl, suspension curves, Klippel, non-linear distortion and displacement?  You appear to claim a degrading effect on distortion from increased displacement. Then say you will be leaning towards 8 drivers in the next paragraph. This may have increased my normal level of confusion by an extra notch or two.  |
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Post by FOH on Dec 3, 2010 7:07:59 GMT -7
"Who's on first?" That dates me I think most here know this, however, for my own benefit, let me take a stab. Ok, there's system displacement, which is a static quantity representing theoretical capability. There is excursion, which represents actual, in use cone travel. Non-linear distortions are increased with cone travel. System capability is increased with displacement. "When the guy playing first base gets paid, who gets the check?" ...."Exactly!" |
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Post by newbieaudio on Dec 3, 2010 13:39:59 GMT -7
It's clear to me that I was NOT clear in my post.
I'm saying that based on Chrisbee's comments about noticing an improvement in sound quality when changing from (4) to (8) AE15s, I'm agreeing with him that this improvement must be due to reduced travel (throw) for any given volume level. Since distortion components increase as the cone travels away from the rest position, increasing the cone area as he did, results in less cone travel for the same output, and therefore lower distortion levels.
Chrisbee said he was surprised with the improvement in SQ because he originally thought that (4) AE15s would be sufficient to keep distortion to minimal (and hopefully inaudible) levels. My reaction was the same as his.
I understand that he also gained potential peak output too, but my surprise was in his comments about sound quality improvement.
Based on his comments about sound quality, I'm now considering building my twin manifolds using (4) Fi 15's per manifold, rather than only using (2) FI 15s each as I had originally planned. I'd change to (4) per manifold to accomplish improved sound quality for music reproduction - not to increase HT LFE capability.
I hope I've been more clear this time.
Concerning the "newbie" aspect, when I started using web bulletin boards, I quickly realized my level of knowledge was insignificant compared to the sum of what I see on this and other boards. The level of sophistication in analysis, creativity and accomplishment in DIY is very high in some cases. So, I accepted this humble "newbie" status and gave myself a user name I thought was appropriate.
I have been playing with DIY for a few decades, but it was only when I discovered this and other boards that I had the opportunity to become more sophisticated. Thomas and others have done the DIY community a great service by taking on the responsibility to help others learn. Fortunately, I work in a technical field surrounded by high-level physics, EE and ME people with whom I can ask questions, and get science answers rather than conjecture. But, it's this board and others that have got me invigorated to even know what questions to ask.
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Post by FOH on Dec 3, 2010 15:05:31 GMT -7
I can't speak for Chrisbee, but I knew exactly what you meant, and I believe Chrisbee did as well.
I wasn't directing any newbie jokes toward you, I merely posted exactly what came for-most to mind; the classic Abbott and Costello bit.
I appreciate your input. I think you were clear,...certainly more clear than I am in most contributions.
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Post by newbieaudio on Dec 3, 2010 19:02:39 GMT -7
foh, I took no offense from any of the comments. I hadn't thought about the Abbott & Costello bit for a while, and I chuckled when I read it.
The problem with writing is that you don't get any instant visual feedback cues from the listener, so you don't know whether you're being clear, or whether you're having half of the conversation in your mind, and the other half on paper.
I don't have the height to fit 18" drivers where I want to put my manifolds in the crawl space, so that's why 15s. And, I don't want to spend more money for an extra (4) drivers and probably amp if I don't need to.
I figured (4) 15s would keep the excursion minimal and distortion minimal for most music, but when Chrisbee described so clearly the attack and decay of the sounds being more realistic, I figured I should ask.
I don't know whether ThomasW is available to comment on this SQ aspect or not between his mini-IB and his (12) driver IB. I know he's said that (4) current 15s should duplicate his (12) driver IB. So, the (4) driver mini-IB may be more comparable to having a single or a pair of current 15s. That difference may or may not be a fair comparison to the change Chrisbee experienced going from (4) to (8) 15s.
So, I'm still curious about any comments or suggestions from anyone who has experienced or not experienced what Chrisbee did when he doubled his drivers.
Staying on the A & C theme: I'm rounding first and wondering who's on second.
Thanks,
Dave
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Post by ThomasW on Dec 3, 2010 23:07:32 GMT -7
While the cult members seem to agree that you don't need (8) 15"s to provide adequate deep bass output for music, your comment does suggest using (8) 15s to improve the quality of music. By doubling your 15s to (8), you're cutting your travel by 1/2. When I've looked at Bl and suspension curves (Klippel), non-linear distortion increases with displacement, and continues to degrade with larger displacements. It appears that going to 8 drivers may be worthwhile for the distortion reduction alone. Since I'm not a head-banger, or concerned about HT extreme audio performance, I'm now leaning toward going to 8 15s for the improvement in music quality - as Chrisbee said: "...made things sound much more real. Leading edge, sustain and decay were far more clearly exposed." Any thoughts? Thanks, Dave Thoughts? Ok... First, Klippel testing is done in a small sealed chamber (think big pressure cooker) and doesn't represent the kind of work load drivers see in the real world. IOW it's an extreme form of testing. Second, we're dealing with LOW bass not midrange, so the threshold of audibility for distortion products is significantly different. Expanding on #2.....As his standard for testing the output of subs Tom Nousaine uses 10% distortion. He claims distortion products of 10% or lower are not audible in the passband where subs operate. I'm not sure how true this 10% figure is, what I know is that people tolerate much higher levels of distortion at low frequencies than they do at higher frequencies. IMO the bottom line is choose the amount of displacement needed for your room. Having 3, 5, 10 times more displacement than needed is just a waste of money. So start with 4 drivers, if later you need more add them |
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Post by chrisbee on Dec 4, 2010 1:34:31 GMT -7
I still stand by my anecdotal evidence on the improved SQ of doubling the number of drivers. The difference was startling in my system. Unfortunately I can't easily mute half of the drivers to check the difference in SQ of having only four 15".
The frequency response of each set of four is different enough to affect listening results. The paper coned drivers droop earlier in the upper bass. While the plastic coned drivers roll off much earlier at the bottom end.
Cynics might easily argue that the addition of the plastic coned drivers made the SQ difference I heard by adding upper bass. It would be hard to contest this suggestion despite my best attempts to match their responses exactly with the BFD.
However, anybody with eight matching drivers could mute half of them and report on the perceived difference in SQ. Bass levels would, of course, have to be rematched with the main speakers with each change in the number of drivers.
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