Imaging ---
I spent about 2 years off and on trying to find out why my center image was not in the center but slightly to one side. I checked all levels, even drivers and acoustic matching. Nothing made the image center. I had even measured the distance from the rear wall to each speaker cabinet to be sure they were the same.
After I moved to another house and did the same setup and the same results - off-center imagee..... I decided to measure from the front of the cabinet to a location distant to my sitting point.
To my surprise, the distance was not the same. But the distance from the back of the wall to speaker was the same!
When I made the distance from speaker cabinet's front to my listening spot the same, then it imaged in the center.
I learned that walls are not necessarily 90 degrees with side walls and there can often be a splay in the wall. The tolerance is fairly loose in the wood frame construction of homes.
The splay was only about <1/2 inch over the speaker seperation distance but it always moved the center image a significant amount. This wall splay occured in two difference houses. So, if you have non-centered image, try measuring from the front of the speaker cabinet to your chosen listening spot. When you get the distances exactly the same, it sounds wonderful.
[PS I measured the distance between the cabinets and found the center and then 90 off that center to the listening position location (feet) and put a tack in the floor/carpet. Moving the cabinets a little to get the distance to the thumb tack equal was my mechanical method]
THx-RNMarsh
I spent about 2 years off and on trying to find out why my center image was not in the center but slightly to one side. I checked all levels, even drivers and acoustic matching. Nothing made the image center. I had even measured the distance from the rear wall to each speaker cabinet to be sure they were the same.
After I moved to another house and did the same setup and the same results - off-center imagee..... I decided to measure from the front of the cabinet to a location distant to my sitting point.
To my surprise, the distance was not the same. But the distance from the back of the wall to speaker was the same!
When I made the distance from speaker cabinet's front to my listening spot the same, then it imaged in the center.
I learned that walls are not necessarily 90 degrees with side walls and there can often be a splay in the wall. The tolerance is fairly loose in the wood frame construction of homes.
The splay was only about <1/2 inch over the speaker seperation distance but it always moved the center image a significant amount. This wall splay occured in two difference houses. So, if you have non-centered image, try measuring from the front of the speaker cabinet to your chosen listening spot. When you get the distances exactly the same, it sounds wonderful.
[PS I measured the distance between the cabinets and found the center and then 90 off that center to the listening position location (feet) and put a tack in the floor/carpet. Moving the cabinets a little to get the distance to the thumb tack equal was my mechanical method]
THx-RNMarsh
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Measure one. You will be surprised how wide band they are. But then how wide do you want it or need it to be for audio?
But of course toroid is fine also.
THx-RNMarsh
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[DBVT = Double Bling Visual Test]
Is this the pure 24K gold frame vs. the Diamond encrusted gold frame? I can tell you now that the blue white diamonds will have a sharper image and a more neutral color BUT the pure gold will have a wonderful warmth to the image.
Joe Kane or the ISF can help you with the difference in the image quality between the different displays. I find them all great until the image moves, then they all degrade rapidly to something closer to old NTSC.
Is this the pure 24K gold frame vs. the Diamond encrusted gold frame? I can tell you now that the blue white diamonds will have a sharper image and a more neutral color BUT the pure gold will have a wonderful warmth to the image.
Joe Kane or the ISF can help you with the difference in the image quality between the different displays. I find them all great until the image moves, then they all degrade rapidly to something closer to old NTSC.
Well as Bonsai found sources of crud go up to over 20MHz. Now at that point you need different techniques to deal with it fully as it will use any house wiring it finds as an antenna so a different detection method would not be the end of the world.
But interesting to be able to measure.
Trivial, you don't know which is which, period. Narrow definition of peeking.
Yeah, been there, done all of that, I agree.
I had a curly one decades ago.
Tuner, tape, CD all centre imaged correctly but phono would not.
I swapped V15 connections but no change.
Balance control did not fix shifted centre.....Turns out I soldered cables with reversed directions.
This cable was the cheapest thinnest shielded cable from a hobbyist store.
Running both cables in the same direction cured the image sideways shift issue....finding that one nearly drove me nuts, I was glad when I found it.
Dan.
Ok and with Peeking ...... if you knew which had 480 and which had 720 and 1080 and 4K and 8K..... and you looked at each of them and said you could see a difference and further that you could tell which one was more accurate picture.... greater detail and more accurate colors, etc, would that viewer be wrong because he peeked?
THx-RNMarsh
I think in the case of HF - i.e. MHz - it just couples across the transformer. Screens help a bit, but at these freqs not all that much. General Wiring capacitive coupling poses a significant problem. Clamp on Ferrites for CM interference can help, but the DM is more difficult in my experience.
I read somewhere that a torroid has a BW of c. 60 kHz.
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.... and if you want to do the ground breaker in a very nice way, you can make one like this....using pcb material with a gap bridged by sm caps. On the other side a nice 75 Ohm strip line. 2nd generation with shorter path works even better. How do I know? I measure with an HP8753D network analyzer. One of several different ones I have on my shelf.
THx-RNMarsh
THx-RNMarsh
I have a 12V toroid, might see what I can do to test that.
At some point you have to do a full emc job to keep the grot out, but I think we are many dB off needing that.
For a grin, here is a 'textbook' filter, designed to hopefully not trip the earth leakage detector. Comments?
Attachments
Richard
you should use a MONO record, or switch your amp in MONO mode, to position your speakers...
after you find the correct position of your speakers you can switch back to STEREO.
The textbook said 200uA. would def need a box. And wouldn't be that much cheaper than the shaffner unless like me you have plenty of small die cast boxes lying around.
I still feel this is belt and braces for anything with decent PSRR, but the inaudible benefits of knowing you have done your best for your electrons are probably worth the small outlay
I still feel this is belt and braces for anything with decent PSRR, but the inaudible benefits of knowing you have done your best for your electrons are probably worth the small outlay
I was just musing about the fact that some people swear by a dedicated spur for audio. Given at least in UK we have ring mains, so the whole system is inside a loop antenna made from mains wiring you have the worst case for grot to get airborne. Things generated within the AV system you can manage, but outside the room you can't.
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