BTY can you reproduce square waves in a non rectangular room, such as one that has curved walls?
Dunno. I'm still peeved that I can't use the chimney as a giant transmission line. At least it avoids the room getting pressurised.
You can contort the truth as much as you want ....
Where did I contort the truth and please don't weasel out. I've zero tolerance for lying.
I've brought an example because you critizised another member (mainly based on intentions only imagined by you), and the psaudio copper publication is from 2017 while your post dated from June 2019; we both know that the probability that two different people write such a similar paragraph (as critic on Oohashi et al.'s 2000 publication) with the exact same chronological order, using exact the same phrases, is next to zero.
The range for possible explanations for such similarities starts at the quite innocent point (forgot to mention the source, although "selling" the critic as ones own) - remember I asked you if you're the author from the psaudio content, no answer - and ends at plagiarizing from either side.
It is as simple as that.
Reports about controlled listening with results contradicting the "usual" wisdom about possible audibilty are routinely ignored
Amusingly stereophile ignore their own test results and then write long articles on why blinded testing doesn't work. Not sure if that makes them experienced or just fearful for their marketing $$$?
Amusingly stereophile ignore their own test results and then write long articles on why blinded testing doesn't work. Not sure if that makes them experienced or just fearful for their marketing $$$?
IIRC they did both, sometimes just contradicting, sometimes with good reason (who could claim infallibility?); but it was my impression that you was talking about this forum (this thread in particular), therefore my response.
Where did I contort the truth and please don't weasel out. I've zero tolerance for lying.
So do I, your smearing attempt is yet another one, so it is dutifully ignored. Source was quoted, everything else is your desperation in finding straws to hang on. You failed, again.
it was my impression that you was talking about this forum (this thread in particular), therefore my response.
I'll be honest discussions on DBLT results are one thing that is never ignored. It creates a lot of discussion. I may have misread Richard but I interpreted it as experienced people post something and no discussion at all.
Same thing with most of the static microphones. Worth on big membranes. Reason why Sennheiser introduced his HF amplitude modulation.Its a real issue with ESL speakers. Humidity/leakage/HF roll-off.
Last edited:
I see a lot of flack levelled at Stereophile, but they have a consistent recipe: give it to a reviewer, then measure it and present the data as it is from both sides.
That some reviewers rave about stuff that is clearly deeply flawed on measurement - and I've seen JA make comments to the effect 'quite why XXX found the sound so beguiling eludes me . . ' etc. only serves to strengthen their position as a serious publication. Warts and all.
One of the best examples of this was the review of a Zanden product costing thousands that measured like absolute trash and yet the reviewer found it 'wonderful'. The manufacturer, based in Japan, ended up dancing around to explain why.
That some reviewers rave about stuff that is clearly deeply flawed on measurement - and I've seen JA make comments to the effect 'quite why XXX found the sound so beguiling eludes me . . ' etc. only serves to strengthen their position as a serious publication. Warts and all.
One of the best examples of this was the review of a Zanden product costing thousands that measured like absolute trash and yet the reviewer found it 'wonderful'. The manufacturer, based in Japan, ended up dancing around to explain why.
So do I, your smearing attempt is yet another one, so it is dutifully ignored. Source was quoted, everything else is your desperation in finding straws to hang on. You failed, again.
Sorry, but that is incorrect; I've quoted the extemely similar paragraph from your post June, 24th :
John Curl's Blowtorch preamplifier part III
and you've not quoted any source, instead your next directly following post was a response to SoundandMotion (who asked for your "promised" link to SY's critic):
Not SY, but myself, see above. Happy now?
John Curl's Blowtorch preamplifier part III
Basically yes. Without filler, any transient perfect XO with at least one slope (acoustically, electrical is irrelevant) steeper than 6dB always has peaking (which means destructive summing) and overlap, one can trade one for the other, though. At least with conventional techniques, the woofer and tweeter diaphragms aligned in the same plane, and no allpasses used. A most general statement is that any transient perfect XO of this kind always has non-zero phase offset, which means they can only be used, if at all, for symmetric W-T-W designs or coaxials.
Once driver offsets and group-delay compensation allpasses are factored in, things change. It then is possible to have something like 4th order slopes with tracking phases throughout the XO region, no peaking, and summed response with zero phase. See here, for example.
At this point circuitry and design process get truly complicated. Today it makes zero sense to strive for linear phase speakers (and compromise other aspects of speaker design) with analog means when it's so trivial to apply an overall phase-correction to the playback source. Assume you have a Linkwitz-Riley-XO at 2kHz, just calculate its phase response (no need to use measured data as that introduces unneccessary errors, rather use curve-fitting), invert it in time, and stuff it into a convolver plugin, done.
So how would a simple two-way like EPI/Burhoe or dynaco a25 style xo (full range on woofer/ just a cap on tweet) fit into this?
tweet would be roughly 60-90 degrees out of phase? and if a second order implemented on the same setup it would be about 180 out from woofer, so swapping polarity on the tweet should/would set it all straight?
In testing I preferred the straight cap over a second order, was just wondering how this equates to the topic at hand where the woofer is left to roll off naturally to a low order high pass on tweet?
(Granted, not many woofers are capable of this but just considering the ones that are)
Thx,
Bob
Last edited:
John, I would not condemn a product as snake oil without clear intent of deception. Perhaps not well understood would be more appropriate for products like OCC silver interconnect wire.
You might if someone made up a story that a claim or a product is snake oil when it really isn't. People do that all the time here, and I think you often do believe them.
In reality, most claims 'called out' as snake oil are merely things that are not well understood. Same as with silver plated copper wire in PTFE, except even less well understood.
Same as with silver plated copper wire in PTFE, except even less well understood.
OK what is not understood here (amongst the EEs, not the rollers).
Details.... silver is used to prevent oxidation of copper when very high temp is used/needed to extrude PTFE onto the wire. Silver doesnt oxidize at that temp so it is plated on the copper when PTFE is the wire's insulator.
Any signal benefit would occur by reducing losses caused by the skin affect.
[dont assume I know or even think it matters in audio. I dont know. But better dielectrics never hurt]
THx-RNMarsh
Any signal benefit would occur by reducing losses caused by the skin affect.
[dont assume I know or even think it matters in audio. I dont know. But better dielectrics never hurt]
THx-RNMarsh
Last edited:
...Lots of anecdotes does not make data.
Actually it does its called 'big data.'
There is so much to investigate using real science, why invent flooby dust? I seriously hoped JN would discuss balanced interconnect and ground loops but he decided to argue zip cord which no one actually uses. Go figure. But no real loss to cloth eared me.
Given a "greenified monster cable and discussion of interstrand conductivity"....
I:
-Detailed how there can be interstrand currents despite the end to end transport current drop being in the low millivolt level, that being faraday's law and dI/dt..
-Pointed out the nature of the currents, that of toroidal axisymmetric.
-Discussed the maximum level of effect possible for skin effect, given that the internal inductance of a pair of cylindrical wires is 30 nH per foot (15 per), so in the limit, that is the maximum energy that can come into play.
-Described how litz prevents skinning induced inductive drop
-How loss of interstrand conductivity approximates litz with the exclusion of fully random conductor placement variations used in litz design.
-How if that interstrand conductivity becomes non linear, the maximum effect that non linearity can have for skin effect is bounded by the total internal inductance.
-How proximity effect works, including links.
-How proximity effect does indeed happen within the audio band for parallel wires of reasonable gauge and insulation thickness.
-That proximity effect will reduce cable inductance a factor of 3 more than skin effect, up to roughly 100 nH per foot.
-That the interstrand conductivity problems will indeed alter proximity effect as well
-Level of effect calculations.
-Test accuracy and repeatability requirements for inductive measure of the effect corrosion can have on inductance vs frequency measurements.
-A test setup to ascertain possible noise and distortion effects for a wire pair with corrosion interstrand, again with level of effect calculations..
And....
The takeaway is...."he talked about zip cord, which nobody uses anymore"
Sigh...
jn
Last edited:
Actually it does its called 'big data.'
Oh dear Mark, you have hit a new low hear. I am sure you have seen the stats on how poor big data is for usable insights.
I tried to illustrate why LLNL only hires the most experienced EEs.
I can give many real world examples of things going awry by in-experienced but otherwise bright EEs.
I had to watch a wonderful young bright EE get let go from LLNL for costly mistake which a more experienced EE would not have made...... he asked me if it was going to end his career... I said probably. [he didnt work for me] A reminder to management Not to hire inexperienced EEs for high risk, high cost projects.
-Richard
Actually, I would blame management entirely. Why in the world would anybody have an inexperienced person in a position to do that much harm?
Here, we are starting to build up hires as the project ramps, and despite the "silver tsunami" here, we still have to bring the younguns up to speed somehow..
jn
Actually it does its called 'big data.'
I’m assuming your comment is tongue in cheek . . . But you never know, perhaps wiki are completely off beam here:-
Big data - Wikipedia
OK what is not understood here (amongst the EEs, not the rollers).
One example is that Bybee devices can and do affect sound, at least in some cases. From what I am told by people I trust, usually they make a good system sound slightly worse, but they can make a not so good system sound slightly better.
My guess would be that they produce very low level distortion when sufficient current is run though them, just a guess though.
The above has nothing to do with the pricing or with the advertising claims. Nobody I know of thinks the advertising claims are truthful. Nobody thinks the things are priced in proportion to whatever effect they have on sound quality, good or bad.
The claim of snake oil seems to come from the advertising. Okay, fine to severely criticize that. But not fine to deny that they can affect sound quality if used in certain ways. That would be to simply to deny reality which is not what scientists are supposed to do. They are supposed to set aside their likes and dislikes and find out the truth whatever it may be.
- Status
- Not open for further replies.
- Home
- Member Areas
- The Lounge
- John Curl's Blowtorch preamplifier part IV