Re: Re: Re: nit-pickung
Sorry for the off-topic, but I was not able to contact John via email.
Hi John,
I never got a chance to speak with you after the audition at the Lexington DIY. Everyone was pretty tired out by that time, since it ended up last to go. I really wanted to get your impressions of the speaker. Perhaps you can send me a private email or message in this regard.
Best Regards,
auplater said:
Sorry for the off-topic, but I was not able to contact John via email.
Hi John,
I never got a chance to speak with you after the audition at the Lexington DIY. Everyone was pretty tired out by that time, since it ended up last to go. I really wanted to get your impressions of the speaker. Perhaps you can send me a private email or message in this regard.
Best Regards,
First of all, the purpose of keeping everything stationary is to see how the pattern effects waves emmitted from the driver. And in fact it is shown that there is a phase lead every time a pattern is moved inward towards the center. A very clear trend. I cannot see how random timing error could form a trend like this.john k... said:
If anyone wishes to obtain the data to play around with in SoundEasy, I'd be glad to dig them up and send them as long as the receiver agrees to post his findings openly. Personally I don't see the value in spending time convincing anyone of anything when they are not doing anything on this subject themselves. Today I just found out that SoundEasy can shift the timing by setting the Pulse delay which may require adjustments to the third digit. Anyone is welcome to do it on thier own.
Even though I have not heard any drivers processed by Bud, but this is the first statement that makes sense to me in the last few pages.jlsem said:
SY said:
I think there are many tests which could be made, including THD and IM. But let me be emphatic. We aren't talking about whether electrons flow over a barrier or through it here and if that makes an audible difference. We are talking about how the cone or diaphragm of a driver vibrates. If it vibrates differently then it has the potential to sound different. If the vibration doesn't change the sound doesn't change. But if it sounds different it must vibrate differently. If you don't buy that then you need to get into a different hobby. 🙂
jlsem said:
It's an interesting thing because if we are able to present objective tests which show a difference which could result in an audible difference the subjectivists would be says see, I told you so. But if you give then an objective test which shows, quantitatively, that no audible change can be present over a 60dB (or greater) range they tell will you the measurement isn't accurate or doesn't measure what needs to be measured. Maybe, but I suspect that a careful set of measurement will clearly show what is different. Remember, I'm not saying there aren't changes. I'm just dead set in the opinion that measurements will show that there are changes. And let’s not forget psychoacoustic affects and the herd mentality. There is always the case where a difference is heard because we think we should hear a difference. You admit yourself that you decided to keep your mouth shut. You were influenced by the herd.
But part of the problem here is also that this is presented as some magical process. I think dlr and I and maybe several others don't see it that way. Rather we (I) see it as, "if it works then it's because it helps damp the cone." Nothing magical about that.
It's also interesting that you bring up Lowthers. It's not a conventional driver. AFAIK, most (all) the drivers have whizzer cones or cones with creases and bends in them. These are all areas which generate impedance missmatched for transverse waves and any type of damping would likely help. It's not whether they sound different when treated is why? I have heard some Lothwers. Not sure which model? They sounded very nice on some music and ear piercing on other. I'm sure that damping the cone or whizzer would help this.
Take a look at this image,
An externally hosted image should be here but it was not working when we last tested it.
In particular the lower left corner is the impulse response of an Ohm F, a speaker I believe Bud used in developing Enable. It clearly shows that almost any type of damping would improve the response. To me the Ohm F always sounded veiled and I would say that this is the primary reason why. Just consider a dinner bell. Ring it. Then put your finger lightly on the bell. It stops ringing pretty fast compared to no finger. And it will also sound (measure) different when struck if your finger is on it.
Anyway, I believe that if the audible differences are there they can be measured. I also believe that the treatment isn’t a magic bullet, and that it is probable, assuming it works, will have different degrees of “success” depending on the characteristics of the driver before application. Honestly I think this entire issue is just revisiting the day of when everyone believed that cone material should have high internal damping. These days the fad seems to be very rigid cones with little or no effective internal damping. The pendulum swings.... I don't think I have anything else to contribute here. I'll just watch. I'm interested in seeing measurements.
That the test was poorly constructed and controlled. Which, to be honest, is far more likely than not in audiophile demonstrations including ones that I have done.
soongsc said:
Yes... DXF, vector EPS or pdf, Illustrator, Coral Draw, that kind of thing. it would be nice to find a windows program that does decent graphics (ie presentation quality).
dave
soongsc said:
Fine, but that could be just an indication of the AC moving forward for what ever reason. Part on my poit is that if you looked at adding/removing delay and then seeing how the difference phase responses over laid you would see one of two things; the phase response could collapse to one, or it wouldn't. I would suspect that the basic phase response would have to collapse. Then any local differences vs frequency would point to where you would expect to see amplitude differences as well.
Another point would be that you can also work with the phase data to determine if it is MP or not. Assuming the data is accurate, the only problem I have with the data is that you didn't do enough with it to determine what it means. Maybe it's just my scientific background but I don't see the point of taking measurements without analyzing what the data means.
Oh, I absolutely buy that, but... vibration is a difficult thing to measure directly, there's a need for a 3D matrix of measurements, and correlating any but the grossest changes with sonics is fiendishly difficult. That's probably why I'm more interested in the controlled subjective testing, but my Inner Measurement Geek won't let me do it without having a suite of measurements ahead of time.
SY said:
SY - I think this area of research needs all the ambivalent geeks we can enlist.
Sooner or later, someone who has measured, then listened to this process may have an "eureka" moment, and stumble upon a (new?) objective technique that identifies the cause. "yup, now that we look at it this way , it's clear something is definitely going on - see my pretty XXXXXXX graphs. No wonder we couldn't find it before"
This is exactly the conundrum we're trying to resolve - How can we systematically analyze what may be incomplete data for an answer that we won't recognize until (or even if?) we see it.
chrisb said:
There is no conundrum. There is, however, an assumption and or implication in this and other posts that we cannot accurately measure an acoustic wave without a shred of evidence that this is the case other than conjecture. Laser interferometry shows details of vibrations in drivers, yet that is still only used as a method to determine details in the source of the signal that we know we can measure acoustically.
Dave
How did I know that they weren't keeping their opinions to themselves for the same reason? I never discussed the results with anyone in the room. I consider the statement "You were influenced by the herd" prejudicial on your part.
That goes without saying, not to mention that the system didn't sound all that great to begin with and the recordings (with one exception) were dubious. My point is that I went in with a skepticism that there would be any difference at all, that those expectations were contradicted by what I heard, and that it wasn't until some time later that I realized that it was the modified driver that sounded less distorted. I'm not going to run out and run the ENABL flag up the pole, but until somebody can show some results from real scientific studies, I'm open to all opinions.
John
dlr said:
Dave, I'm not saying that the data set of accurate measurements already in hand don't already contain the information that answers this particular question - "these guys say they hear an improvement , what's the cause?" Excuse me from assuming that some objectivists (present company excluded) won't be satisfied until proving the listeners "wrong"
What I am suggesting is that sometimes it takes years of looking at data to see something new - and in other cases altogether new types of measurement methods or analysis are required.
For example, for how many years was the simple number of amplifier THD foisted upon the mainstream market as a predictor of "sonic accuracy", and that more decimal points guaranteed happier listening experience?
Well, I think that for most of us that gross simplification is a fond (?) memory, and we generally accept that music consists of huge variations of transient, harmonic content - time and space, if you will. At the very least the harmonic spectra of distortion needs to be considered when asking why a 5 watt tube with more than 1% THD at rated output might sound more "musical*" at listening levels than a 200W SS unit with .0005%.
*I'm waiting for a single non-listening test for that
chrisb said:
I don't that any of us are trying to prove that someone is not hearing a change. It's likely that they are if there has been a change in the frequency of some magnitude above JND (Just Noticeable Difference). I am certainly not saying that no one is hearing a difference.
The point is simply that any of the changes made can be measured now. An acoustic wave does not have some underlying, indeterminate or unknown quality requiring some new measurement ability that we lack.
Excuse me for being skeptical that any of us, me included, are going to determine some new measurement paradigm that has eluded experts the world over.
The analogy doesn't hold. The ability existed then to measure local and global negative feedback, the issue there. No new measurement techniques were invented.
That's actually a good example. The FR may be very good in a really good tube amp and to consider just the FR is not considering the high distortion characteristics. Likewise with drivers just looking at FR and/or CSD totally ignores the significant distortion inherent in them and what impact a mod has on them.
As far as harmonic spectra, an impulse is the most harmonic-rich signal that exists. A true infinite impulse has every harmonic possible in the spectrum. A finite impulse such as those used in measurement systems has harmonic content that is sufficient to cover the spectrum measured. The impulse certainly has more harmonic content in a single event than exists in any music signal. That's the reason it's the standard test signal for FR. Distortion measurments have other requirements and use a different scheme, though some distortion characteristics can be extracted using the MLS, but it's still all measurable now.
Dave
Sy,
You might also consider some unreasonably complex and dynamic orchestral music.
A suggestion would be Rhapsody in Blue, because everyone knows it here in the US, but played by the Chicago Symphony with James Levine conducting. A Deutsche Grammophon recording, 431 625-2.
At the other end of the scale, Jessica Williams "Gratitude" a Candid recording CCD79721.
I am utterly certain you have your own list laid out. The DG recording is one to own, just for it's phenomenal musicianship. The density of clearly recorded instruments, within an unbelievably explosive musical event.
The Williams CD is one of the best recordings of sparse piano playing I have. Clearly shows the entry and decay of single notes, chords and has a broad spectrum of dynamics. Both are worth having just to enjoy. They will stress any playback system and even show off just how good Red Book can be.
Bud
You might also consider some unreasonably complex and dynamic orchestral music.
A suggestion would be Rhapsody in Blue, because everyone knows it here in the US, but played by the Chicago Symphony with James Levine conducting. A Deutsche Grammophon recording, 431 625-2.
At the other end of the scale, Jessica Williams "Gratitude" a Candid recording CCD79721.
I am utterly certain you have your own list laid out. The DG recording is one to own, just for it's phenomenal musicianship. The density of clearly recorded instruments, within an unbelievably explosive musical event.
The Williams CD is one of the best recordings of sparse piano playing I have. Clearly shows the entry and decay of single notes, chords and has a broad spectrum of dynamics. Both are worth having just to enjoy. They will stress any playback system and even show off just how good Red Book can be.
Bud
auplater:
regarding the weight, I think the interest is in the differential. I don't have the scales with resolution to check, this should be an open request to the forum.
The drivers are in hand...parameters will be determined...they'll be mounted in a "first run" baffle on enclosure. Results from that will be used to tweak the baffle lay-out. Final crossover and treatment will follow after that.
Drivers will be a Silver Flute:
http://www.madisound.com/catalog/pr...=1676&osCsid=b27136a76bf185a40a0a38d4d3e6eff0Sliver Flute
and a Vifa (oem) #BC25SC15-04, similar to the D26NC55
regarding the weight, I think the interest is in the differential. I don't have the scales with resolution to check, this should be an open request to the forum.
The drivers are in hand...parameters will be determined...they'll be mounted in a "first run" baffle on enclosure. Results from that will be used to tweak the baffle lay-out. Final crossover and treatment will follow after that.
Drivers will be a Silver Flute:
http://www.madisound.com/catalog/pr...=1676&osCsid=b27136a76bf185a40a0a38d4d3e6eff0Sliver Flute
and a Vifa (oem) #BC25SC15-04, similar to the D26NC55
chrisb said:
Yes, but you have to start at the beginning. And you have to start by looking for something that is well defined. A good on axis measurement will contain all the information about the cone vibration, and any variation with treatment, in it. After all, if all you change is the addition of the treatment then it is the only variable. Any differences in a correctly performed set of measurement will expose that difference if it is significant. Soongc's measurements were a starting point but he didn't attempt to reduce the different phase response to a single result by removing/adding delay. Since there doesn't appear to be any gross difference in the FR in soongc's measurements we are at a loss to explain the phase differences. There is more than enough data in his measurement to start to look for why the result is different.
There are a number of things he could have done using SoundEasy. 1) add/remove phase. 2) verify that the response was/was not minimum phase. 3) Subtract the untreated SPL data form the treated SPL data and look directly at the differences. Performing the last task is straight forward and would immediately show any differences in amplitude response between the treated and untreated drivers but it has to be done correctly. First repeated measurement of the untreated driver need to be made and the difference between measurements looked at to determine the expected error band. Then the procedure and be repeated after treatment is applied. If differences are found that are greater than the established error band there is conclusive evidence of a change in response. I just did some quick tests on a tweeter and as far as the error band was concerned I was able to determine that the difference between repeated measurements was better than -50 dB over the range of interest. That is, if I take two measurement of the same tweeter under the same conditions and subtract one form the other the difference small than -50dB (or 0.3%). So if I were to Enable this tweeter and subtract the untreated response form the treated response anything greater than -50dB in the result would be a difference I could attribute to the treatment. It doesn’t address how the differences come about, but it does identify what the differences are. Shouldn't this satisfy even the guy who was saying that the differences may be in the -30 to -40 dB range? What is left is whether the listener can hear these differences and if so, is what he is hearing a manifestation of the difference in frequency response or something else?
Bud, I knew Jessica Williams back in the days when she was George. He (at the time) was a local Big Deal, played at the clubs I frequented, and was the in-house piano talent at Peabody. Great to know that Williams is still around.
Sorry for the OT.
Sorry for the OT.
Sy
I wasn't aware there was an OT to this thread.
Don't miss the Rhapsody, no matter how jaded your taste in that piece. It is the Groffe orchestration and unlike anything you have encountered. Even Romy the Cat was caught off guard.....
Bud
I wasn't aware there was an OT to this thread.
Don't miss the Rhapsody, no matter how jaded your taste in that piece. It is the Groffe orchestration and unlike anything you have encountered. Even Romy the Cat was caught off guard.....
Bud
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