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#1
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mixer measurements
i decided to run some measurements on the Behringer mixer i just got then
compare it to some other mixers. here's what i got: Behringer MX 2642A % THD 50 Hz .048 100 Hz .05 1000 Hz .05 10 kHz .058 15 kHz .064 IM distortion (60 & 7kHz) .06 % noise* .0355 mv Soundcraft F1-16 %THD 50 Hz .048 100 Hz .05 1000 Hz .052 10 kHz .06 15 kHz .068 IM .052 % noise* .035 mv Mackie 32-8 %THD 50 Hz .052 100 Hz .058 1000 Hz .05 10 kHz .064 15 kHz .072 IM .06 % noise* .09 mv no mixer: straight from sig gen to analyzer %THD 50 Hz .046 100 Hz .048 1000 Hz .05 10 kHz .056 15 kHz .062 IM .052 % noise* .014 mv *methodology: noise measurements made referenced to -40 dB input and 0 dB output with sig gen muted and one ch open all others down. all other measurement made with 150 ohm source at -40 dB into mic input. mixer output set to 0 dB into active balanced (transformerless) meter. tone controls all at neutral. in "straight through" measurements the sig gen output was increased by 20 dB. conclusion: i was rather surprised at how well the 2642 tested relative to the other units. the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. my equipment seems to be functioning within its specified tolerances. http://www.pi-usa.com/ag51/ag51g.htm#SPECIFICATIONS |
#2
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"Tim Perry" wrote in message ... i decided to run some measurements on the Behringer mixer i just got then compare it to some other mixers. here's what i got: Behringer MX 2642A % THD 50 Hz .048 100 Hz .05 1000 Hz .05 10 kHz .058 15 kHz .064 IM distortion (60 & 7kHz) .06 % noise* .0355 mv Soundcraft F1-16 %THD 50 Hz .048 100 Hz .05 1000 Hz .052 10 kHz .06 15 kHz .068 IM .052 % noise* .035 mv Mackie 32-8 %THD 50 Hz .052 100 Hz .058 1000 Hz .05 10 kHz .064 15 kHz .072 IM .06 % noise* .09 mv no mixer: straight from sig gen to analyzer %THD 50 Hz .046 100 Hz .048 1000 Hz .05 10 kHz .056 15 kHz .062 IM .052 % noise* .014 mv *methodology: noise measurements made referenced to -40 dB input and 0 dB output with sig gen muted and one ch open all others down. all other measurement made with 150 ohm source at -40 dB into mic input. mixer output set to 0 dB into active balanced (transformerless) meter. tone controls all at neutral. in "straight through" measurements the sig gen output was increased by 20 dB. conclusion: i was rather surprised at how well the 2642 tested relative to the other units. the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. ** Most likely just measued the usual way. my equipment seems to be functioning within its specified tolerances. http://www.pi-usa.com/ag51/ag51g.htm#SPECIFICATIONS ** But is not up to modern standards. Decent audio generators have less than 0.001% THD at 1kHz nowadays. ........... Phil |
#3
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Tim Perry wrote:
i decided to run some measurements on the Behringer mixer i just got then compare it to some other mixers. here's what i got: snip near identical figures *methodology: noise measurements made referenced to -40 dB input and 0 dB output with sig gen muted and one ch open all others down. all other measurement made with 150 ohm source at -40 dB into mic input. mixer output set to 0 dB into active balanced (transformerless) meter. tone controls all at neutral. in "straight through" measurements the sig gen output was increased by 20 dB. conclusion: i was rather surprised at how well the 2642 tested relative to the other units. the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. my equipment seems to be functioning within its specified tolerances. http://www.pi-usa.com/ag51/ag51g.htm#SPECIFICATIONS Your measurement gear is rubbish. With residual figures like that - you'll never be able to measure anything meaningful. You're simply measuring the test equipment. Audio Precision kit for example, typically measures 0.0007% THD ( 7 parts per million ) that's -104dB SINAD if you prefer a dB version, with output looped back to input ( certainly at 1 kHz ). Graham |
#4
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"Pooh Bear" wrote in message
Tim Perry wrote: i decided to run some measurements on the Behringer mixer i just got then compare it to some other mixers. here's what i got: snip near identical figures Agreed, the test results are very similar, thus raising the possibility that these are not actually tests of the UUTs, but instead tests of the residuals of the test equipment. *methodology: noise measurements made referenced to -40 dB input and 0 dB output with sig gen muted and one ch open all others down. all other measurement made with 150 ohm source at -40 dB into mic input. mixer output set to 0 dB into active balanced (transformerless) meter. tone controls all at neutral. in "straight through" measurements the sig gen output was increased by 20 dB. http://www.pi-usa.com/ag51/ag51g.htm#SPECIFICATIONS The INTRINSIC DISTORTION * Harmonic Low Distortion Fast Response 20 Hz to 10 kHz less than 0.05% less than 1% 10 kHz to 20 kHz less than 0.08% less than 1% Intermodulation less than 0.03% Incidental FM(3.15 kHz) less than 0.01% This would be pretty hot stuff in 1965, but by modern standards it's pretty grim. I'll give you modern farily mninmal standards in a nutshell: All spurious responses and noise 100 dB or down (0.001%) or better. Frequency response (I don't see it on the web page) within 0.1 dB or better with phase response to match per minimum phase. And here's SOTA: All spurious responses and noise 120 dB or down (0.0001%) or better. Frequency response within 0.02 dB or better with phase response to match per minimum phase. I think that test equipment that met minimum standards would tell a different story. You can emlulate really pretty good modern test equipment with a good computer audio interface and software such as the Audio Rightmark analyzer. conclusion: i was rather surprised at how well the 2642 tested relative to the other units. In fact, you seem to have published tests of essentially the residuals of your test gear, twice. the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. my equipment seems to be functioning within its specified tolerances. http://www.pi-usa.com/ag51/ag51g.htm#SPECIFICATIONS Your measurement gear is rubbish. Agreed. Looks nice, though. It's really a historic artifact from the 1960s. I built stuff that was better from modified Heathkits in the 1970s. With residual figures like that - you'll never be able to measure anything meaningful. You're simply measuring the test equipment. Agreed. First step in any measuement paradigm is know your geat. As you suggest, that means looping it and seeing what the numbers are. Audio Precision kit for example, typically measures 0.0007% THD ( 7 parts per million ) that's -104dB SINAD if you prefer a dB version, with output looped back to input ( certainly at 1 kHz ). I think that's the old stuff or maybe APs somewhat conservative specs. I'm told that the new stuff is of the same order of a LynxTWO, whose test results I published at http://www.pcavtech.com/soundcards/LynxTWO/index.htm .. It shows up to 115 SNAD with a 20-20K measurement bandwidth, and 107 dB at comparable bandwidths to an AP S2. |
#5
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Tim Perry wrote:
the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. Specifications are never measurments. Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. When chosing those values, manufacturers are walking a line between how good they want their gear to appear on paper and how many manufacturing rejects and/or customer returns they are willing to tolerate. snip -- ================================================== ====================== Michael Kesti | "And like, one and one don't make | two, one and one make one." | - The Who, Bargain |
#6
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thanks for you comments gentelman.
my gear works fine for my normal aplications (level setting and troubleshooting, often in high RF envirnments). i was able to get a much better reading using a DAW and soundcard as a source (.01% THD on the Behringer), however this is through the line input. i think iwill have to build a input pad if i want to continue. i was mostly curious as to noise mesurments. is the procedure i described sufficienty accurate to compare the results with published specs? with 15 uv of self noise is this equipment sufficient to measure noise in modern gear? http://www.pi-usa.com/aa51a/aa51ag.htm#SPECIFICATIONS |
#7
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For the noise measurement what did you terminate the input with, a short or
a metal film resistor? Rgds: Eric "Tim Perry" wrote in message ... thanks for you comments gentelman. my gear works fine for my normal aplications (level setting and troubleshooting, often in high RF envirnments). i was able to get a much better reading using a DAW and soundcard as a source (.01% THD on the Behringer), however this is through the line input. i think iwill have to build a input pad if i want to continue. i was mostly curious as to noise mesurments. is the procedure i described sufficienty accurate to compare the results with published specs? with 15 uv of self noise is this equipment sufficient to measure noise in modern gear? http://www.pi-usa.com/aa51a/aa51ag.htm#SPECIFICATIONS |
#8
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"Eric K. Weber" wrote in message ... For the noise measurement what did you terminate the input with, a short or a metal film resistor? Rgds: Eric sig gen switched from operate to test, which mutes the osc .... 150 ohm output. |
#9
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"Tim Perry" wrote in message
my gear works fine for my normal aplications (level setting and troubleshooting, often in high RF envirnments). That's fine. i was able to get a much better reading using a DAW and soundcard as a source (.01% THD on the Behringer), however this is through the line input. i think iwill have to build a input pad if i want to continue. Agreed. If one uses an audio interface as test equipment, one quickly finds out that the input sensitivity of the interface is not ideal or even usuable in every reasonable and common application. My approach is to use a 5 K ohm "AB" type 2 watt potentiometer to set input sensitivity as desired. in combination with a good RMS DVM for measuring actual operational levels. I was mostly curious as to noise mesurements. Noise measurements only make sense when the measurement bandwidth is defined. This includes flat (really 20-20 KHz @ -3 dB), A and C weighting. Noise measurements only make sense when they can be related a standard signal level, such as 0 dB Vu. You can find a detailed set of guidelines for making technical measurements of audio gear at http://www.aes.org/standards/b_pub/aes-6id-2000.pdf is the procedure i described sufficienty accurate to compare the results with published specs? No. (Teset equipment spec web page) http://www.pi-usa.com/aa51a/aa51ag.htm#SPECIFICATIONS with 15 uv of self noise is this equipment sufficient to measure noise in modern gear? That's about 95 dB below 0 dBu, which is too close to the performance of modern audio equipment for accurate measurements. As a general rule measuring equipment should perform at least 10 dB better than the standards that you seek to confirm or deny compliance with. |
#10
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Arny Krueger wrote:
"Pooh Bear" wrote in message Audio Precision kit for example, typically measures 0.0007% THD ( 7 parts per million ) that's -104dB SINAD if you prefer a dB version, with output looped back to input ( certainly at 1 kHz ). I think that's the old stuff or maybe APs somewhat conservative specs. I'm told that the new stuff is of the same order of a LynxTWO, whose test results I published at http://www.pcavtech.com/soundcards/LynxTWO/index.htm . It shows up to 115 SNAD with a 20-20K measurement bandwidth, and 107 dB at comparable bandwidths to an AP S2. Yup, it's typical figures for System One or Portable One. It's seems remarkable now just how long they've been around. Graham |
#11
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"Michael R. Kesti" Tim Perry wrote: the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. Specifications are never measurments. ** Rubbish. Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. ** Shame about all those "min", "typical" and "max" figures in data sheets then. When chosing those values, manufacturers are walking a line between how good they want their gear to appear on paper and how many manufacturing rejects and/or customer returns they are willing to tolerate. ** Most equipment specs represent typical figures found by measurement on samples - unless otherwise specified. ............ Phil |
#12
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Phil Allison wrote:
"Michael R. Kesti" Specifications are never measurments. ** Rubbish. How CAN one argue with logic such as that? Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. ** Shame about all those "min", "typical" and "max" figures in data sheets then. I downloaded the specifications of the three mixers referenced in this thread's base note, and not one of them provided "min", "typical", and "max" parameter values. There were plenty of occasions of "greater than" and "less than" for values of distortion, noise, and such parameters, and untoleranced values of impedance, max levels, and the like. Perhaps you would be so kind as to supply a link to a spec of a pro audio product that includes min, typical, and max parameter values. When chosing those values, manufacturers are walking a line between how good they want their gear to appear on paper and how many manufacturing rejects and/or customer returns they are willing to tolerate. ** Most equipment specs represent typical figures found by measurement on samples - unless otherwise specified. If this is true, then about half of the delivered units are going to perform worse than those figures. Would you find it acceptible to discover that you had purchased a unit that measured worse than its published specs? -- ================================================== ====================== Michael Kesti | "And like, one and one don't make | two, one and one make one." | - The Who, Bargain |
#13
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"Michael R. Kesti" wrote in message
Tim Perry wrote: the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. Specifications are never measurments. Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. When chosing those values, manufacturers are walking a line between how good they want their gear to appear on paper and how many manufacturing rejects and/or customer returns they are willing to tolerate. FWIW, totally agreed. |
#14
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"Michael R. Kesti" Phil Allison wrote: "Michael R. Kesti" Specifications are never measurments. ** Rubbish. How CAN one argue with logic such as that? ** You posted no proof of an wild claim. I should have said **BULL****** !!! Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. ** Shame about all those "min", "typical" and "max" figures in data sheets then. Perhaps you would be so kind as to supply a link to a spec of a pro audio product that includes min, typical, and max parameter values. ** You said: " Specifications are never measurments." ** Most equipment specs represent typical figures found by measurement on samples - unless otherwise specified. If this is true, then about half of the delivered units are going to perform worse than those figures. ** But only by trivial amounts. Would you find it acceptible to discover that you had purchased a unit that measured worse than its published specs? ** Yep - when the specs are all **way above* what is needed to do the job. But this has nothing to do with what maker's specs tell you. ............ Phil |
#15
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"Arny Krueger" "Michael R. Kesti" Tim Perry wrote: the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. Specifications are never measurments. Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. When chosing those values, manufacturers are walking a line between how good they want their gear to appear on paper and how many manufacturing rejects and/or customer returns they are willing to tolerate. FWIW, totally agreed. ** Not worth a pinch of ****. ............... Phil |
#16
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#17
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In article znr1093262843k@trad, Mike Rivers wrote:
In article writes: ** Shame about all those "min", "typical" and "max" figures in data sheets then. I downloaded the specifications of the three mixers referenced in this thread's base note, and not one of them provided "min", "typical", and "max" parameter values. In typical Phool style, the subject has been changed from "mixers" (the final product) to "components" (the little things inside the product). He's just messing with you. Pay him no mind. He won't go away. Hell, some of the Chinese component manufacturers don't even have "min," and "max" figures, just "typical" ones and some of those have to be taken with a grain of salt too. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#18
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"Mike Rivers" = professional Parrott and snipping maniac. ** Replacing the missing ***CONTEXT ** yet again !!!!!!!!!!!!!! Instead, specifications are chosen values of parameters that, when measured, are promised to be no worse than the values specified. ** Shame about all those "min", "typical" and "max" figures in data sheets then. I downloaded the specifications of the three mixers referenced in this thread's base note, and not one of them provided "min", "typical", and "max" parameter values. In typical Phool style, the subject has been changed from "mixers" (the final product) to "components" (the little things inside the product). ** Mr Kesti made a **totally wrong** claim - so I posted the facts. " ** Most equipment specs represent typical figures found by measurement on samples - unless otherwise specified. " Mr Kesti then showed us that he **cannot read** by quoting specs with " better than " and "greater than" in the wording. The OP's example had no such words - nor do the vast majority of technical specs. It therefore comes under my " ..... unless otherwise specified ". Go choke on that you vile smelling NG Parrott. ............. Phil |
#19
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#20
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On 23 Aug 2004 13:08:34 -0400, (Mike Rivers)
wrote: Go get a real job and you'll see how it's actually done. Uhhhh, Mike, do you seriously think anyone on this newsgroup would hire this, er, _disturbed_, fellow? Willie K. Yee, M.D. http://users.bestweb.net/~wkyee Developer of Problem Knowledge Couplers for Psychiatry http://www.pkc.com Webmaster and Guitarist for the Big Blue Big Band http://www.bigbluebigband.org |
#21
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"Phil Allison" wrote in message ... "Arny Krueger" "Michael R. Kesti" Tim Perry wrote: the online spec sheet claims a THD of .007% @ +4 dB i wonder if its an actual measurement or is derived in some fashion. Specifications are never measurments. after 30 years of bench and field repair i figure i have a glimmering of how to interpret most electronic specs. i have been telling people that it just not that hard to build a good amplifier anymore yet i was still taken by surprise by the excellent specs on a unit that i got for only $170. having lived through an era where 125 W/ch car stereo amps were often sold with 2 amp fuses to the 13.8 volt inputs i sometimes get a bit skeptical when specs seem too good to be true. so if i had it to phrase over again i think i would say: i wonder if there is some way to derive or extrapolate a resonably accurate measurement of THD with such poor and substandard test gear as i have managed to aquire. (i suspect the answer is no way in heck, but one can hope) i guess its back to subjective evaluation for now thanks for your input folks |
#22
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Tim Perry wrote:
having lived through an era where 125 W/ch car stereo amps were often sold with 2 amp fuses to the 13.8 volt inputs i sometimes get a bit skeptical when specs seem too good to be true. Through it? I don't think that era is over yet. Except perhaps in that they are now sold as 500 W/ch amps.... so if i had it to phrase over again i think i would say: i wonder if there is some way to derive or extrapolate a resonably accurate measurement of THD with such poor and substandard test gear as i have managed to aquire. (i suspect the answer is no way in heck, but one can hope) It is easy to measure THD at high levels. And at low levels, measuring THD isn't very useful. And if you want to buy an HP 334B distortion test set, I have one in need of some repair work that I am considering putting up on Ebay. i guess its back to subjective evaluation for now That's what it all comes down to in the long run to some extent. THD is handy for comparing similar systems, though. The distortion meter is great for finding maximum output levels on tapes, for instance. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#23
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"Mike Rivers" Phil Allison ** Mr Kesti made a **totally wrong** claim - so I posted the facts. I don't remember his claim, ** Go read the thread you lazy, stinking prick !!!!! " ** Most equipment specs represent typical figures found by measurement on samples - unless otherwise specified. " Mr Kesti then showed us that he **cannot read** by quoting specs with " better than " and "greater than" in the wording. ( snip piles of mindless Parrot brained ****e ) Now you may consider a couple of early units "samples" but that's not what I call samples. ** Who gives a rats arse what Mike Rivers calls anything ???? The turd has never worked in the electronics industry and has no clue. Go get a real job and you'll see how it's actually done. ** The Rivers parrot should take his own advice - only no-one would employ the useless idiot. ............. Phil |
#24
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"Willie K.Yee, M.D Uhhhh, Mike, do you seriously think anyone on this newsgroup would hire this, er, _disturbed_, fellow? ** Arse licker. ........... Phil |
#25
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"Scott Dorsey" wrote in message ... Tim Perry wrote: having lived through an era where 125 W/ch car stereo amps were often sold with 2 amp fuses to the 13.8 volt inputs i sometimes get a bit skeptical when specs seem too good to be true. Through it? I don't think that era is over yet. Except perhaps in that they are now sold as 500 W/ch amps.... so if i had it to phrase over again i think i would say: i wonder if there is some way to derive or extrapolate a resonably accurate measurement of THD with such poor and substandard test gear as i have managed to aquire. (i suspect the answer is no way in heck, but one can hope) It is easy to measure THD at high levels. And at low levels, measuring THD isn't very useful. And if you want to buy an HP 334B distortion test set, I have one in need of some repair work that I am considering putting up on Ebay. i used to have a tube type HP. cant remember the model. used it as a noch filter one time to null a buzz out of a phone line. had a HP333 at another place. i sure like the autonull in my Potomac. it has a handy freq counter built in too! |
#26
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"Tim Perry" wrote in message
... so if i had it to phrase over again i think i would say: i wonder if there is some way to derive or extrapolate a resonably accurate measurement of THD with such poor and substandard test gear as i have managed to aquire. (i suspect the answer is no way in heck, but one can hope) The good news is that it's possible to derive quite a good measurement of THD using a relatively affordable computer soundcard such as an M-Audio Delta or a CardDeluxe (look on e-bay; they show up all the time). The bad news is that, once you've done the THD measurement, you still don't know squat about how good the amplifier might or might not sound, because THD correlates damned poorly with the latter unless you use it to find grossly defective amplifiers. But the further good news is that you can use the soundcard to make some tests that are actually relevant, looking at the actual harmonic spectrum of the distortion produced by a single frequency, or doing intermodulation distortion measurements of various sorts. Peace, Paul |
#27
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In article wkyeeATbestwebDOTnet writes: Go get a real job and you'll see how it's actually done. Uhhhh, Mike, do you seriously think anyone on this newsgroup would hire this, er, _disturbed_, fellow? It was a rhetorical comment. Phil may be very competent in the real world (assuming he's old enough to drink, vote, and get shot at) and just be an asshole where people can't get to his real throat. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
#28
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"Mike Rivers" ** Mike is a total incompetent in the real world (assuming he's real enough to drink, vote, and get shot at) and is simply an asswipe in usenet where people can't get to his throat. ........... Phil |
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