SY said:
There's a nice recent paper on how a spark is actually a doublet, it made total sense in the end and rationalized some of these difficulties around DC pressure. I can't find the link right now.
GRollins said:
He'd look pretty silly if he claimed you put words in his mouth before you actually did so. His meaning was quite clear. This is just your usual modus operandi of deliberately misinterpreting what people have said in an attempt to make them look foolish. It’s time to come up with a new M.O.
john curl said:
That would be the same Moncrieff who wrote of my Common-Base
moving coil stage, "Of course it inverts polarity".
All this talk about waveforms reminds me of a head-butting session I had with Fred once upon a time. We were into some kind of yik-yak about how much wattage one of the Aleph amps would deliver before the current limiter widget kicked in. I did a quick scratch calculation and posted the result. In mere moments Fred came back at me screaming that I was wrong, that the number was something else much, much higher. To make a long story short, it turned out that I was posting RMS and he was posting peak numbers. We were both right, just looking at the thing from different points of view. But...given that to the best of my recollection he never posted peak numbers in any other post, I've always thought it likely that he chose peak on purpose, just to have something to argue about. It would be in character for him to do so.
I've already specified that I'm talking room pressure, which given the conditions I've posted will always remain positive. If others want to 'argue peak wattage' by taking it in another direction, that's fine. It'll hover on the verge of being a semantics argument for a couple more pages, with nothing noteworthy being added. I'll stick with RMS, thank you, and you guys can talk peak for a bit longer if it makes you happy. Or go to the on/off pulse, in which case the microphone has a much easier time tracking the signal, thus getting rid of that annoying DC, cone-standing-still for a moment thing. At that point we're still going to be arguing whether less-positive is the same thing as negative. In other words, semantics. Depending on your point of view, either one is right.
Draw a cube on a piece of paper. Then stare at it until it pops out of the page, then goes back into the page. To claim that either view is more right than the other is a waste of time. Some days I fall for it. Today is one of the days when I don't.
Besides, if you want to get argumentative about it, SY, there is such a thing as 'negative pressure.' It's pressure that's less positive than your reference pressure. For anything greater than 0psi, that's a valid statement. Now you can argue with yourself instead of me. Mind you, it's all in your point of view and how you approach the semantics of the thing, but if that's where you want to go, then do so with my blessing. I'll sit back and watch.
I'd still like a recording that was flat down to DC. We spend vast amounts of energy trying to extend the high end and lower distortion in the upper two octaves, but almost completely ignore the bottom octaves. It would be interesting to hear a recording that was truly flat to DC. Has anyone ever measured available, usable low end information on any recording format? I know Boyk did high end measurements and found stuff far beyond what most people expect, but has he or anyone else done low end?
No, I most definitely don't want a listing of boom-boom rap junk. First, it doesn't impress me artistically. Second, it's not all that deep. Third, I doubt that you could find a recording of that sort that would qualify as well recorded in the audiophile sense, though I suppose there's probably a minute subset of the boom-boom market that might buy such a thing, so perhaps I'm wrong on that one.
It's not hard to find 30Hz. I remember the notes for one of the Wilson Recordings organ records mentioning that there was a pedal note that happened to create a standing wave right where the microphone was hung. On top of that, the microphone itself had a peak in that same range, so the result was pretty impressive. Single digit frequencies would have been verboten on LPs for fear of exciting arm/cartridge resonances, but that wouldn't be a problem for any of the digital formats.
Grey
I've already specified that I'm talking room pressure, which given the conditions I've posted will always remain positive. If others want to 'argue peak wattage' by taking it in another direction, that's fine. It'll hover on the verge of being a semantics argument for a couple more pages, with nothing noteworthy being added. I'll stick with RMS, thank you, and you guys can talk peak for a bit longer if it makes you happy. Or go to the on/off pulse, in which case the microphone has a much easier time tracking the signal, thus getting rid of that annoying DC, cone-standing-still for a moment thing. At that point we're still going to be arguing whether less-positive is the same thing as negative. In other words, semantics. Depending on your point of view, either one is right.
Draw a cube on a piece of paper. Then stare at it until it pops out of the page, then goes back into the page. To claim that either view is more right than the other is a waste of time. Some days I fall for it. Today is one of the days when I don't.
Besides, if you want to get argumentative about it, SY, there is such a thing as 'negative pressure.' It's pressure that's less positive than your reference pressure. For anything greater than 0psi, that's a valid statement. Now you can argue with yourself instead of me. Mind you, it's all in your point of view and how you approach the semantics of the thing, but if that's where you want to go, then do so with my blessing. I'll sit back and watch.
I'd still like a recording that was flat down to DC. We spend vast amounts of energy trying to extend the high end and lower distortion in the upper two octaves, but almost completely ignore the bottom octaves. It would be interesting to hear a recording that was truly flat to DC. Has anyone ever measured available, usable low end information on any recording format? I know Boyk did high end measurements and found stuff far beyond what most people expect, but has he or anyone else done low end?
No, I most definitely don't want a listing of boom-boom rap junk. First, it doesn't impress me artistically. Second, it's not all that deep. Third, I doubt that you could find a recording of that sort that would qualify as well recorded in the audiophile sense, though I suppose there's probably a minute subset of the boom-boom market that might buy such a thing, so perhaps I'm wrong on that one.
It's not hard to find 30Hz. I remember the notes for one of the Wilson Recordings organ records mentioning that there was a pedal note that happened to create a standing wave right where the microphone was hung. On top of that, the microphone itself had a peak in that same range, so the result was pretty impressive. Single digit frequencies would have been verboten on LPs for fear of exciting arm/cartridge resonances, but that wouldn't be a problem for any of the digital formats.
Grey
fizzard said:
His post #4643 came before my post #4662, which is the one he was complaining about. Perhaps you need a new PC if yours is showing those posts in reversed order.
Grey
I remember that Wilson recording. It has so much bass that the Linn people next door complained that the sound was coming up through the air conditioning ducts! It was scary, but IF you ever did a music recording at Grace Cathedral, you would understand how it was done.
The 30ips full track master recorder that I designed for Dave Wilson worked down to 10Hz. CD or SACD should go much lower, but the mikes will not work to DC exactly, unless you seal their back chamber. B&K shows how low you can go.
The 30ips full track master recorder that I designed for Dave Wilson worked down to 10Hz. CD or SACD should go much lower, but the mikes will not work to DC exactly, unless you seal their back chamber. B&K shows how low you can go.
john curl said:
Wow! I'm so famous that even Heyser recognized me as a leader in the field! (He must have had one heck of a crystal ball....)
john curl said:
I still have the record. It's not the kind of thing I'd use to set crossover levels with, but it's seriously fun to listen to. Better still if you can get someone who's never heard it and doesn't know what's coming. Facial expressions are delightful when people get their lungs massaged for the first time.
Between that and Dafos you can rearrange someone's hairdo if your subs are up to the task.
Okay, so I can guesstimate that the Wilson masters go to ca. 10Hz depending on associated equipment. That's a good start. The obvious follow-on question is how much of that made it to the available recordings.
Sheffield? Crystal Clear? How did the direct-to-disk guys fare?
Where do Telarc, et. al. clock in? Assuming CD/SACD, they would no longer be limited by arm resonances on turntables and they would be one of the companies I'd expect to push things lower if they could.
Grey
scott wurcer said:
I tried to read some of her works but had to give it up, I was getting an ulcer and she was making me throw up on my shoes.
scott wurcer said:
Please keep looking Scott, these are the sort of things that I actually DO read. If it's anomalous, contentious, new and/or cutting edge -I'm there. I wana know.
GRollins: For the reproduction of the given DC works, you'd have to use pressurized/release-'positive' vibrational devices. Ie, single sided positive, like the human voice and the ear designed to hear it, or the voice designed to engage the ear. Hard to say on that one. But I'm sure that such is obvious after a few seconds of reflection.
Damn, here I was worried about straying too far from the Blowtorch while all you guy's were finishing a keg in the back room 😉 😉 😉
Bob Cordell said:
I did manage to come up with a 'solve' for this issue about a decade ago, and have been using it in passive crossovers ever since. However, I'm saving it's release as a thing that can be grabbed and used by others until We actually release a commercial product with it in the crossover. I've never connected a driver out of phase in a given system or topology, and I've never suffered any integration issues for it. Partially due to this particular little trick. I'm a bit sensitive to absolute phase, or like to imagine I am. Whatever. Since I'm not a champ at electronic design considerations, I'm not totally sure it can be used in standard electronics crossover design, but It seems obvious to some extent..that it can. Maybe. Passive topology is non-patentable, so I've kept it to myself for the time being. Believe me, I'd rather share it, and that has been my desire since I stumbled into it.
Bob Cordell said:
Seems to me that absolute phase is not an issue in speaker design, since by definition of absolute phase, any error is easily corrected by reversing the connection. I'd expect that you're familiar with the many historical papers on crossover design in the AES where first a flat all pass response was sought after, then ones with linear phase characteristics in order to preserve waveshape. No simple passive solution was found that offered good out of band attenuation as I recall. I posted a long list of AES papers on the subject to the Bass discussion list many years ago, don't have it handy at the moment.
Witold Waldman, the author of CALSOD, has an excellent bibliography in the manual (237 references). Scrolling down to the start and searching on phase should bring up several references:
http://www.users.on.net/~audiosoft/usermanual.html
Or are you suggesting that if absolute phase is audible, as is generally accepted, then there would be no correct connection for a speaker with a reversed driver such as the midrange? You'd be suggesting then that non-linear phase is audible? I've read the papers and from memory test subjects could only reliably detect a non-linear phase response, typical of an all-pass speaker crossover, through headphones with mostly non-musical test signals such as banging blocks. As I recall it could be detected but not in a reflective room with most musical source material.
I've said for years I'll take a linear phase design if I can get it without a large increase in complexity, without poor off axis response, and without a significant increase in distortion due to shallow crossover slopes.
I believe that absolute phase is generally accepted to be audible in the low bass, so it would seem that this is the driver that should be wired in phase with the input terminals. The common LR4 crossover has the drivers in phase, but as I'd expect you know is an all-pass design.
Pete B.
Oh yes..why I ended up in this thread in the first palce......
I went searching on the forum for 'best MC transformer', and this thread came up.
Any specific candidates, guys? The ones that go in the innards, not the finished item. Low impedance carts are the preferred type.
"No simple passive solution was found that offered good out of band attenuation as I recall."
Mwwwwuuhahahhahahahahahahahaaaaaaaa... (Evil laugh). That's what I'm talkin' about.
I went searching on the forum for 'best MC transformer', and this thread came up.
Any specific candidates, guys? The ones that go in the innards, not the finished item. Low impedance carts are the preferred type.
"No simple passive solution was found that offered good out of band attenuation as I recall."
Mwwwwuuhahahhahahahahahahahaaaaaaaa... (Evil laugh). That's what I'm talkin' about.
In that case, your statement that the pressure doesn't go negative, by your definition, is wrong. It does, on the return of the cone to neutral.
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