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Dirty Digital [sic.]
Don Pearce wrote: Eeyore wrote: You have the map co-ords now - why not go and measure yourself ? Might do just that. Oh - avoid entering the newly extended 'congestion zone'. It's just on the edge. You can park nearby and stay out of it. Graham |
Dirty Digital [sic.]
Eeyore wrote:
Don Pearce wrote: Eeyore wrote: Don Pearce wrote: Eeyore wrote: tony sayer wrote: Eeyore scribeth thus Please explain how MRI scanners came into this thread. Well if its magnetic fields your after they don't usually come much higher?.. I said they were *electro-magnetic* fields. Then there was no need to go to the huge expense of a steel box. Any old conductive mesh draped around the place would have done as well. The contractors said 2mm mild steel. It's THEIR job to make it work (and it did) so why would I complain ? I've forgotten; what was your role in the project? Measurement consultant. Using tools RELEVANT to audio recording not some bleeding IEC document that doesn't start 'til 150 kHz ! Graham Ah, right. So what did you actually measure, and with what? d |
Dirty Digital [sic.]
Eeyore wrote:
Don Pearce wrote: Eeyore wrote: Don Pearce wrote: Eeyore wrote: Don Pearce wrote: Eeyore wrote: tony sayer wrote: Eeyore scribeth thus tony sayer wrote: Eeyore scribeth thus tony sayer wrote: Or did you mean that your friends make rooms that are screened against magnetically induced fields?.. Is 2mm mild steel over say 10 m3 going to do that ? So you really think that there are magnetic fields around external to a top rate studio that are going to produce that field level?. A NMRI scanner isn't that well screened;).. It's Don who claims they're magnetic. Yet they don't fall off with distance appreciably. Theres more to the screening of an NMRI scanner .. its to do with keeping signals -out- rather then in. Even the 1-2 odd Tesla field isn't likely to cause a problem in the studio next door to the manky guitar pickup coil company;).. Please explain how MRI scanners came into this thread. They are sources of very powerful magnetic fields, and the steel enclosure under discussion can only have been designed to exclude magnetic fields. MRI was a guess at a possible source powerful enough to require such exclusion. Do they 'hum' day in, day out at frequencies between the low hundreds Hz and mid kHz ? No. Just hammering away at a few Hz when they are running. As I thought. So not THAT then. You have the map co-ords now - why not go and measure yourself ? Might do just that. Please do. It'll freak you. All you need is a few tens of turns of wire on a bog roll (or a guitar pickup in a box) into a modestly high gain amp ( ~ 60dB) . We used a PigNose for general use and a Radford ANM03 ? for more specific detailed measurement stuff. Graham Right - you just answered my question from another post. I even have a Pignose. d |
Dirty Digital [sic.]
Eeyore wrote:
Don Pearce wrote: Eeyore wrote: You have the map co-ords now - why not go and measure yourself ? Might do just that. Oh - avoid entering the newly extended 'congestion zone'. It's just on the edge. You can park nearby and stay out of it. Graham I can carry what I need on my bike. d |
Dirty Digital [sic.]
Don Pearce wrote: Eeyore wrote: Don Pearce wrote: Eeyore wrote: Don Pearce wrote: Eeyore wrote: tony sayer wrote: Eeyore scribeth thus Please explain how MRI scanners came into this thread. Well if its magnetic fields your after they don't usually come much higher?.. I said they were *electro-magnetic* fields. Then there was no need to go to the huge expense of a steel box. Any old conductive mesh draped around the place would have done as well. The contractors said 2mm mild steel. It's THEIR job to make it work (and it did) so why would I complain ? I've forgotten; what was your role in the project? Measurement consultant. Using tools RELEVANT to audio recording not some bleeding IEC document that doesn't start 'til 150 kHz ! Ah, right. So what did you actually measure ? Induced noise per EN55103-2. 50Hz -10 kHz. Annex A. and with what? A ****ing bog roll. (withe some wire round it.) Graham |
Dirty Digital [sic.]
In article , Eeyore rabbitsfriendsandrel
scribeth thus tony sayer wrote: Eeyore scribeth thus Please explain how MRI scanners came into this thread. Well if its magnetic fields your after they don't usually come much higher?.. I said they were *electro-magnetic* fields. Graham Make yer mind up;).. -- Tony Sayer |
Dirty Digital [sic.]
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Dirty Digital [sic.]
In article , Don Pearce
scribeth thus Eeyore wrote: tony sayer wrote: Eeyore scribeth thus tony sayer wrote: Eeyore scribeth thus tony sayer wrote: Or did you mean that your friends make rooms that are screened against magnetically induced fields?.. Is 2mm mild steel over say 10 m3 going to do that ? So you really think that there are magnetic fields around external to a top rate studio that are going to produce that field level?. A NMRI scanner isn't that well screened;).. It's Don who claims they're magnetic. Yet they don't fall off with distance appreciably. Theres more to the screening of an NMRI scanner .. its to do with keeping signals -out- rather then in. Even the 1-2 odd Tesla field isn't likely to cause a problem in the studio next door to the manky guitar pickup coil company;).. Please explain how MRI scanners came into this thread. Graham They are sources of very powerful magnetic fields, and the steel enclosure under discussion can only have been designed to exclude magnetic fields. MRI was a guess at a possible source powerful enough to require such exclusion. d And also to keep RF out. Very interesting devices having been in one;!.. -- Tony Sayer |
Dirty Digital [sic.]
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Dirty Digital [sic.]
You wouldn't believe this guy. His name's Glen or Glenn btw. He had some amps that 'hummed' a bit and claimed they didn't hum outside the (insert famous name guitarist's) own studio. Now this studio has already had a fair bit of screening, plus balanced mains so I was somewhat sceptical of anything other than original poor design or ageing. I picked up one of the amps in question and rotated it by its handle to see if I could detect any magnetic pickup affected by movement. NO. I was later to be held 'irresponsible' for picking up the amp by the handle because it was 'so old' it might have broken. Later, I spent a lot of time trying my very best to explain to the tech, exactly how 'hum' gets picked up into guitars and guitar amps. Result. He blanked me. He was so technically incompetent that he ran to the studio manager to 'complain' about me. Apparently science isn't his thing. You would not believe the ****wits that exist in this industry. I would .. there're all over the place;!.. I believe the reason for his reactions was at least partly fear of his boss. Since I'm so ****ing ****ed off about it, I'll name him. It's Mark Knopfler and the studios in question are British Grove Studios, possibly the most state of the art studios I've ever seen but populated by servile ****s, 'yes men' and ****wits. Worse still, I suggested one of these amps be taken to an independent repair guy (no connection with me at all ) who is well recognised as an expert in that field. Knopfler's 'tech' turned up and said ot the guy 'it doesn't work right'. NO hint of what was wrong with it or any expectation of what he wanted. So 'my' guy examined it. Found that poor quality modifications had been made to it, repaired them, tested it thoroughly, found it to be 'on spec' and returned it only when I asked to be met with 'it's no better'. And in the process this other guy has now got a 'black mark' from these ****s too. Yep moron's the lot of 'em seen exactly that happen;(... Trust me, never trust a \'guitar tech\'. Graham I\'ll take your word for it seems guitar bozo\'s like things all fecked up... -- Tony Sayer |
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