fdegrove said:
The original poster was asking about whether it's best to use long interconnects or long speaker cables, which started a discussion as to why one would go one way or the other which led to the issue of balanced interfaces. The issue of balanced interfaces was then extended from line levels to the loudspeaker in the sixth post by purplepeople when he said:
If they would make all drivers dual voice coil, then speaker cable could also be balanced. Unless... does someone know a way to do that?
Your concern over the question asked by the threadstarter seems to be coming rather late in the game. Like 40 posts late. If nothing I've said has anything to do with the original question, then neither did the sixth post in this thread as well as all the subsequent responses in the same context.
se
Hi,
Unless we have ourselves a perfectly symmetrical LS ( which most are not) that theory just won't hold water.
Just know that I followed the thread from the start and although it wasn't all that well formulated I took the effort of looking up the product used and concluded neither was balanced.
Hence my advice to use normal interconnects and speaker cables.
40 posts later this poor fellow is now so confused that he still doesn't know which way to turn, no thanks to you?
Wouldn't it be wiser to ask what the Zo of the preamp is, what the Zin of the x-over is and how far apart he really needs to separate them from the speakers instead of all this intelectual masturbation which is pretty fruitless by nature?
Not to mention the mindless reponses I've seen so far?
Com'on Stevie we can do better than that, can't we?
Put down that J and return to earth in a truly balanced fashion...
Unless we have ourselves a perfectly symmetrical LS ( which most are not) that theory just won't hold water.
Just know that I followed the thread from the start and although it wasn't all that well formulated I took the effort of looking up the product used and concluded neither was balanced.
Hence my advice to use normal interconnects and speaker cables.
40 posts later this poor fellow is now so confused that he still doesn't know which way to turn, no thanks to you?
Wouldn't it be wiser to ask what the Zo of the preamp is, what the Zin of the x-over is and how far apart he really needs to separate them from the speakers instead of all this intelectual masturbation which is pretty fruitless by nature?
Not to mention the mindless reponses I've seen so far?
Com'on Stevie we can do better than that, can't we?
Put down that J and return to earth in a truly balanced fashion...
Hi,
Like most engineers you assume perfect product; perfect caps. perfect resistors, perfect OPT with prefect symmetry and so on.
Anyway this is besides the point of discussion here, as Fred Dieckman has pointed out previously a LS doesn't have any CMRR.
A LS, at best, presents a symmetrical transducer. If it were to be fed from a perfectly balanced source no common noise would be passed.
For that LS, assuming more than a single driver without x-over, all x-over components need to be in series with send an return lines and of equal value, i.e. electrically the same.
Any offset from the feeding source will also offset the balance in the transducer throwing out CMMR.
Now, for all intent and purpose, getting upset about speaker cable picking up interference is more than just a little paranoid given the impedances here.
Cheers,
Like most engineers you assume perfect product; perfect caps. perfect resistors, perfect OPT with prefect symmetry and so on.
Anyway this is besides the point of discussion here, as Fred Dieckman has pointed out previously a LS doesn't have any CMRR.
A LS, at best, presents a symmetrical transducer. If it were to be fed from a perfectly balanced source no common noise would be passed.
For that LS, assuming more than a single driver without x-over, all x-over components need to be in series with send an return lines and of equal value, i.e. electrically the same.
Any offset from the feeding source will also offset the balance in the transducer throwing out CMMR.
Now, for all intent and purpose, getting upset about speaker cable picking up interference is more than just a little paranoid given the impedances here.
Cheers,
"Can any one else understand him, in terms of engineering or physics and not just moral support?"
In reply to Fred's comment above, for the record, after my last name follows M.A.Sc., P.Eng., which is backed up with 15+ years of engineering experience, so drop the "moral support" crap! Steve is going outside of the normal traditional box, but his points aren't completely without basis or relevance.
Also for the record, I think my earlier comments were misunderstood. I suspect that I belong to a very small minority who finds that both Fred and Steve have technical viewpoints that are worth considering. Personally, I can't stand the flame wars that result of their combined participation, but I have learned a great deal from both and would find it a serious loss if either stopped participating in these forums.
Fred, my earlier comments to you were honest and genuine and most certainly not an attempt to incite you or drag you into a flame war. I am honestly curious as to your technical viewpoint. I have learned from you in the past and hope to do so again in the future.
The beauty of this forum is that a very diverse set of experiences and viewpoints become available for consideration. Some are more valuable than others, granted, but that is all part of the learning process.
Metalman
In reply to Fred's comment above, for the record, after my last name follows M.A.Sc., P.Eng., which is backed up with 15+ years of engineering experience, so drop the "moral support" crap! Steve is going outside of the normal traditional box, but his points aren't completely without basis or relevance.
Also for the record, I think my earlier comments were misunderstood. I suspect that I belong to a very small minority who finds that both Fred and Steve have technical viewpoints that are worth considering. Personally, I can't stand the flame wars that result of their combined participation, but I have learned a great deal from both and would find it a serious loss if either stopped participating in these forums.
Fred, my earlier comments to you were honest and genuine and most certainly not an attempt to incite you or drag you into a flame war. I am honestly curious as to your technical viewpoint. I have learned from you in the past and hope to do so again in the future.
The beauty of this forum is that a very diverse set of experiences and viewpoints become available for consideration. Some are more valuable than others, granted, but that is all part of the learning process.
Metalman
Actually, Frank, I'm not and never have been an engineer. So I don't assume anything other than a two terminal device and Kirchoff's Law. So... how can any of those things you name cause the current in each of the legs of the speaker feed to be anything other than antisymmetric?
And agreed, it's normally not relevant. But not always, as I found out many years ago when we lived near a 50kW radio station.
And agreed, it's normally not relevant. But not always, as I found out many years ago when we lived near a 50kW radio station.
Hi,
No problem...but lets discern symmetrical drive and balanced drive.
The device being driven, while symmetrical in construction depends on the signal it receives.
All in all this is a passive device.
I'm talking a regular speaker here, not a dual voice coil one where, in theory we could create a virtual midpoint.
To make it easier, let's assume a PP OTP driven output where the ground on the OTP is left floating. That would present a nice symmetrical drive to our single unit FR LS.
Would this setup make the LS cable impervious to EMI or RFI pickup?
No! It wouldn't...But if we shield the speakerwire and ground it properly at one end it would be better.
You really need almost perfect symmetry to take advantage from CMMR in audio. Lose it somewhere along the line and you'll have lost it forever.
In order to call a device truly balanced it should only present the two opposing signal polarities at the output, a LS can only transmit this signal, it can't help in any way CMMR in any other way than being as electrically symmetrical in build as it can possibly be.
Cheers,
No problem...but lets discern symmetrical drive and balanced drive.
The device being driven, while symmetrical in construction depends on the signal it receives.
All in all this is a passive device.
I'm talking a regular speaker here, not a dual voice coil one where, in theory we could create a virtual midpoint.
To make it easier, let's assume a PP OTP driven output where the ground on the OTP is left floating. That would present a nice symmetrical drive to our single unit FR LS.
Would this setup make the LS cable impervious to EMI or RFI pickup?
No! It wouldn't...But if we shield the speakerwire and ground it properly at one end it would be better.
You really need almost perfect symmetry to take advantage from CMMR in audio. Lose it somewhere along the line and you'll have lost it forever.
In order to call a device truly balanced it should only present the two opposing signal polarities at the output, a LS can only transmit this signal, it can't help in any way CMMR in any other way than being as electrically symmetrical in build as it can possibly be.
Cheers,
Hi,
As far as I'm concerned you are allowed to explain this reply for exactly 55 forum pages, 276 million words and hopefully a few jokes in the process....
Now, say what?
'Fraid you lost me on page one already ...and no I won't 'splain the difference between symmetry (albeit apparent), balanced drive etc...
For someone who lectures others on terminology on absolute polarity and phase I expect to get straight facts, not aragnatic like fantasies on what could be's.
Guess you do have us on the mary go 'round once again, right?
Cheers,
As far as I'm concerned you are allowed to explain this reply for exactly 55 forum pages, 276 million words and hopefully a few jokes in the process....
Now, say what?
'Fraid you lost me on page one already ...and no I won't 'splain the difference between symmetry (albeit apparent), balanced drive etc...
For someone who lectures others on terminology on absolute polarity and phase I expect to get straight facts, not aragnatic like fantasies on what could be's.
Guess you do have us on the mary go 'round once again, right?
Cheers,
fdegrove said:
Why would there not be a virtual midpoint in a single voice coil loudspeaker? If the voicecoil is perfectly symmetrical (as well as the mechanical elements involved), then the midpoint of the voice coil would be the midpoint.
Common-mode rejection isn't about being impervious to EMI or RFI pickup. It's about rejecting that which IS picked up, and how equally it's picked up on each line, which will depend on the cable geometry and shielding if any.
Shielding is another issue.
Another way of saying this is that CMRR depends in part on the symmetry of the output and input impedances.
That's pretty much how every other differential input device achieves common-mode rejection.
se
He's all yours
"Can any one else understand him, in terms of engineering or physics and not just moral support?"
"In reply to Fred's comment above, for the record, after my last name follows M.A.Sc., P.Eng., which is backed up with 15+ years of engineering experience, so drop the "moral support" crap! Steve is going outside of the normal traditional box, but his points aren't completely without basis or relevance."
I think I meant a something a little more specific than having P. Eng. in your title. I applaud your accomplishment. But, you might be a Civil Engineer for all I know, which is hardly an asset in this debate. I don't know what field your job experience is in. Why are these relevant credentials if we have no idea what you do?
No one that I can see, has offered any physics, engineering, measurements, or anything else of any substance pointing
to any reason for a loudspeaker having any even slightly significant common mode impedance with respect to ground.
Mr. Eddy has wiggled around with statements like:
"In an ideal world, yes. But as I said previously, the common-mode signal needs to remain common-mode and not get converted to differential mode."
"Dunno. Never measured it. But I suspect it'd be quite high."
And concise mathematical analysis like: 1-1=0
People come here with real questions and get pretentious posturing from guys who must realize, even to themselves, that they have no idea what they are talking about. This stuff confuses the guy who actually wants to have USEFUL advice. It annoys the people who know enough to see it is total nonsense, and creates needless personality battles over issues that should have nothing to do with personalities. There seems to only be one person here who gets some perverse pleasure out of this self serving pontification. It appears that post like his are not meant to inform others or even for him to learn anything. Babble on, anybody that can swallow any of these nonsensical post deserves the consequences of the misinformation. Just don't accuse me of picking on him out of spite. If you can deal with his pointless posturing, I guess I can too.
"Can any one else understand him, in terms of engineering or physics and not just moral support?"
"In reply to Fred's comment above, for the record, after my last name follows M.A.Sc., P.Eng., which is backed up with 15+ years of engineering experience, so drop the "moral support" crap! Steve is going outside of the normal traditional box, but his points aren't completely without basis or relevance."
I think I meant a something a little more specific than having P. Eng. in your title. I applaud your accomplishment. But, you might be a Civil Engineer for all I know, which is hardly an asset in this debate. I don't know what field your job experience is in. Why are these relevant credentials if we have no idea what you do?
No one that I can see, has offered any physics, engineering, measurements, or anything else of any substance pointing
to any reason for a loudspeaker having any even slightly significant common mode impedance with respect to ground.
Mr. Eddy has wiggled around with statements like:
"In an ideal world, yes. But as I said previously, the common-mode signal needs to remain common-mode and not get converted to differential mode."
"Dunno. Never measured it. But I suspect it'd be quite high."
And concise mathematical analysis like: 1-1=0
People come here with real questions and get pretentious posturing from guys who must realize, even to themselves, that they have no idea what they are talking about. This stuff confuses the guy who actually wants to have USEFUL advice. It annoys the people who know enough to see it is total nonsense, and creates needless personality battles over issues that should have nothing to do with personalities. There seems to only be one person here who gets some perverse pleasure out of this self serving pontification. It appears that post like his are not meant to inform others or even for him to learn anything. Babble on, anybody that can swallow any of these nonsensical post deserves the consequences of the misinformation. Just don't accuse me of picking on him out of spite. If you can deal with his pointless posturing, I guess I can too.
Sorry everyone, I didn't mean to ask if anyone knew how to make speaker cables balanced. I'll try not to ask such provocative questions anymore.
ensen.
PS: Amt, why not try both and see which one you like better. As you can see, arguments can be made for either option and few others you probably wish you didn't now know about. In the end, only you can decide which you like better, regardless of what I, Si, Eddi or Franki might vie for.
ensen.PS: Amt, why not try both and see which one you like better. As you can see, arguments can be made for either option and few others you probably wish you didn't now know about. In the end, only you can decide which you like better, regardless of what I, Si, Eddi or Franki might vie for.
fdegrove said:Really?
Do you actually realise what kind of impedances we're talking about?
Believe me that's entering serious compulsive paranoia.
A straightjacket anyone?
Um, excuse me, Frank, my memory isn't what it used to be, but wasn't it you who was worried about the deliterious sonic effects of a little bit of oxide on the outside of a wire? That it was so deliterious that it was preferable to coat the wire with a hugely thicker layer of polyurethane?
What size straightjacket do you wear?
By the way, if the impedances are so low as to render any induced noise so insignificant that even pondering it is entering serious compulsive paranoia, then those same low impedances would also render any effects due to speaker cable dielectrics just as insignificant, yes?
So the next time someone ponders using speaker cables with a dielectric any better than PVC, can we count on you to be there to fit them for a straightjacket?
se
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