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Post by mazeroth on Feb 27, 2008 20:56:47 GMT -7
Just wondering if anyone knew if any of the popular IB drivers available have had distortion measurements taken on them?
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Post by carvernut on Feb 27, 2008 22:40:05 GMT -7
measurements how? in room, drivers themselves raw out of room... clearify please
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Post by mazeroth on Feb 28, 2008 5:54:32 GMT -7
The drivers themselves, preferably tested on a baffle. I know some of them use the XBL2 technology but I was wondering how they stacked up to other low distortion drivers like Dayton's RS390s. This will not need extreme output but every once in a while I will crank it up.
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Post by diycable on Feb 28, 2008 18:22:17 GMT -7
The drivers themselves, preferably tested on a baffle. I know some of them use the XBL2 technology but I was wondering how they stacked up to other low distortion drivers like Dayton's RS390s. This will not need extreme output but every once in a while I will crank it up. Can you point me to the distortion measurements on the RS390s?
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Post by chrisbee on Feb 29, 2008 2:21:18 GMT -7
REW does distortion measurements for 2nd harmonic.
Third harmonic distortion is presently disabled but JohnM promised that it will be enabled in a new release. I have previously posted some 2nd harmonic distortion figures for my original 4 x AEIB15s down to 5Hz without attracting much comment.
Apparently I should not have gone below 10Hz as this is not presently supported by REW but the figures do show an obvious trend. These earlier drivers have a 32Hz Fs with massive +16dB BFD boost at 20Hz to lift the bottom end.
REW 95dB target level. Galaxy 140 SPL calibrated with pink noise at listening position. REW sinewave generator using F follows cursor with wireless mouse. Actual dB(C) reading on Galaxy 140 SPL meter is shown. With falling frequency the distortion figures tended to waver between two extremes. So I watched the trend, averaged the readings and wrote them down.
Hz.....dB(C)...2nd%
50.....97.6.....0.33 40.....98.0.....0.41 30.....97.5.....0.46 25.....97.9.....0.48 20.....98.5.....1.0 15.....96.3.....0.5 10.....96.8.....2.0 9.....91.4.....2.5 8.....84.6.....2.5 7.....81.4.....2.3 6.....79.0.....~4
It is very unpleasant to have continuous tones running at high levels at low frequencies so I never repeated the test for 100dB target level or higher as I had originally intended.
I believe distortion will be read on the fly during the REW sweep in a future release.
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Post by carvernut on Feb 29, 2008 6:21:00 GMT -7
bwuahaha lets see JL Fathom try to match those ;D
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Post by mazeroth on Feb 29, 2008 6:36:51 GMT -7
Can you point me to the distortion measurements on the RS390s? I haven't seen distortion measurements on the RS390s but I have seen them on its little brother, the RS315. Zaph had a page up comparing it against a $700 Skaaning sub he has and it was neck and neck, with the Skaaning winning by a small margin. Monte Kay tested an early sample of the RS315 and the data can be downloaded from this page from the Download Data link: www.mfk-projects.com/rs_12_hi-fi.htm
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Post by mazeroth on Feb 29, 2008 7:18:29 GMT -7
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Post by carvernut on Feb 29, 2008 8:16:56 GMT -7
noob question... how do you read these distortion charts? i can understand the percentile numbers well enough but i'm at a loss on the charts
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Post by ThomasW on Feb 29, 2008 8:55:11 GMT -7
noob question... how do you read these distortion charts? i can understand the percentile numbers well enough but i'm at a loss on the charts Here's a quick guide..... This graph shows the amount of second order harmonic distortion (purple lines) compared to a frequency response plot (green lines) This allows the viewer to see how much distortion there is at a given frequency. This is a 12" woofer so it's expected that the distortion will increase as the frequencies being reproduced go higher.
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Post by carvernut on Feb 29, 2008 9:45:09 GMT -7
so... how does this relate to a percentile number? such as does 3dB's less = 1% ?
like when Chris was talking about his distortion on his IB showing from .2% - 1% how would you explain that in chart terms?
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Post by chrisbee on Feb 29, 2008 11:57:50 GMT -7
bwuahaha lets see JL Fathom try to match those ;D You cynic you! ;D Whoops! You've seen Ilkka's JL Fathom review too? How many AEIB15s and EP2500s can you buy for the price of a single Fathom? JL V IB? No contest
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Post by carvernut on Feb 29, 2008 12:32:13 GMT -7
How many AEIB15s and EP2500s can you buy for the price of a single Fathom? JL V IB? No contest JL Fathom, 13.5" sub 2600 burst watt amp total cost 3400.00 400.00 = manifold wood, screws, glue and wire... 750.00 = 3 EP-2500 amps = roughly 5,000 voltamps 2,000.00 = 20 AEIB15's total cost 3,150.00 would anyone like to experience 10hz at 130dBs? ;D so... for 3400.00 would you like one 13.5" sub, or 20 15" subs which sound better and FAR outperform the single 13.5"? now wait... if you think 3400.00 only gets you a small speaker and not much performance... here is what you really get!!! the most distortion bang-for-you-buck!!! ((((http://www.soundandvisionmag.com/spe...subwoofer.html)))) i notice this review was pulled from the S&VM website... probably because JL complained that they were receiving a "bad rap" from Tom because... like with Bose they were put to the test and found lacking.There's a new review on Sound and Vision Magazine by Tom Nousaine. It isn't very long but contains some measurements. One sentence caught my eye... Although the F112 has relatively high low-frequency output (104 dB or greater at every frequency from 32 Hz up to the top of its range), it was not able to reproduce 25 Hz with less than 10% distortion. It can make plenty of sound at this frequency (104 dB), but with 40% distortion where the upper harmonics are approaching the amplitude of the fundamental. Notice that the measurements were done in 1/8 space @ 2 m (corner of a room). Though when comparing TN's and Yates' data on Genelec HTS6, they seem pretty close, meaning TN's numbers are pretty close to what one gets in 1/2 space (GP) @ 2 m. Also notice that TN uses 6.5 cycle long "bursts", not longer sine waves or sweeps. greater than 104dB's from 32hz up... OMG for less than half the price my IB puts out over 120dB from 14hz up and well over 130dB's from 20hz up... and for 3400.00 you would think one of JL's CEO's could come down, take 5 mins and run some test sweeps and check to see if each unit is working properly... I'm sorry even if this unit in this review was defective that speaks VERY poorly of JL's quality controll and care about testing each and every sub before it leaves the facility which is what the need and SHOULD do i mean when you don't even check the demo unit to be reviewed... that just shows they don't care about the review, let alone the units that their consumers buy but for 3400.00 i would want a freq wave chart,freq response chart, distortion chart and amplifier power output chart in a manila binder with at least two peoples signatures saying that that information was correct and had been performed upon that unit at that date and what equipment was used to check and measure it with
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Post by chrisbee on Feb 29, 2008 12:59:04 GMT -7
There must be more to life than sub-10Hz ultra low distortion and ultra high output performance.
The trouble is everything else providing this much fun is probably illegal. (or very expensive) ;D
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Post by carvernut on Feb 29, 2008 13:01:34 GMT -7
There must be more to life than sub-10Hz ultra low distortion and ultra high output performance. The trouble is everything else providing this much fun is probably illegal. (or very expensive) ;D hmmm... adding more speakers and trying to destroy your house with a 5hz 140dB sine wave!!!! ;D now thats fun! heck theres a money maker... go into the demolition buisness and just install monster IB's into old homes to be torn down... turn on the Bridge scene from LOTR or Black Hawk Down: Ireane and watch the house implode
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Post by chrisbee on Feb 29, 2008 13:59:22 GMT -7
carvernut
I think we ought to tell people that just because you can reach these outrageous SPLs doesn't mean that one has to listen at such levels when enjoying films and music at home.
The ability to play very loud and clean deep down into the infrasonics means that at typical domestic SPLs and frequencies the distortion levels are even lower. Far lower than any commercial subwoofer can manage at far higher and easier frequencies.
Low distortion with almost unlimited headroom means that things sound very real indeed. No other subwoofer can provide instantly recognisable high fidelity down to any frequency you are ever likely to find on your CDs or DVDs.
Just a few seconds listening to an IB is enough to spoil your enjoyment of any other subwoofer forever. Unless you are able to build an IB then you had better not listen to one.
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Post by carvernut on Feb 29, 2008 14:27:50 GMT -7
carvernut I think we ought to tell people that just because you can reach these outrageous SPLs doesn't mean that one has to listen at such levels when enjoying films and music at home. *innocent* i have done nothing wrong, NOTHING! so what if i can't hear and my walls have screws sticking out of them?! Doesn't every home have cracks and broken supports from nothing more than natural causes? I tell you this... i have but accelerated the goal that nature herself shall someday bring upon us all... the utter destruction of our homes!!!! IT'S ALIVE I TELL YOU!!! ALIVE!!! Just a few seconds listening to an IB is enough to spoil your enjoyment of any other subwoofer forever. Unless you are able to build an IB then you had better not listen to one. actually it took my ears about a week to change over to IB sound... at first i thought i just blew 1500.00 and had nothing to show for it ;D but yes, it's very realistic and... If i am elected President i promise an Infinite Baffle system for all homes in America!!! For all homes should have two things, a beautifull girl and an outrageous IB sub!!! although... i think i have the two reversed... the IB comes FIRST!!!!
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Post by carvernut on Feb 29, 2008 14:32:04 GMT -7
sorry for above post, i've had coffee and expresso for lunch
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Post by mazeroth on Feb 29, 2008 18:52:59 GMT -7
sorry for above post, i've had coffee and expresso for lunch No need to apologize. I'd vote for you!
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Post by carvernut on Mar 1, 2008 12:03:01 GMT -7
well hopefully i'll have some charts for everyone sometime within a week on my IB, i'm going to go home after work today and order the Mic and preamp to make measurements with... i think i can take distortion measurements with REW software on my computer... won't be perfectly accurate due to not being perfect setup
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