but seriously...
Seems to me, most of these brouhahas evolve when the "experts in their field" take themselves way too seriously and loose sight that this is "hobbyland" for most of us. The p*&^ing matches are amusing, though, usually when opinion masquerades as factual knowledge.
I know I've been chastised innumerable times in a number of forums by some of the "gurus" for questioning their stringent theory vs. empiricism; I just move on to another topic for a few months... no loss to me.
I have gained quite a bit of insight into audio reproduction from reading these forums. I just wish some of the 'ego issues" could be left aside.
John L.
Seems to me, most of these brouhahas evolve when the "experts in their field" take themselves way too seriously and loose sight that this is "hobbyland" for most of us. The p*&^ing matches are amusing, though, usually when opinion masquerades as factual knowledge.
I know I've been chastised innumerable times in a number of forums by some of the "gurus" for questioning their stringent theory vs. empiricism; I just move on to another topic for a few months... no loss to me.
I have gained quite a bit of insight into audio reproduction from reading these forums. I just wish some of the 'ego issues" could be left aside.
John L.
Lynn Olson said:
Hornys are in conflict with the conventional hi-fi world, I've been listening to anti-horn views from "high end" types for well over 30 years. So many of us develop a thick hide, a penchant for conflict and a contempt for hi-fi orthodoxy. Like when we hear some johnny come lately SET fan telling us we "have" to use tubes with horns, I'll jump those jaspers in a hot minute. Not on this forum of course though.
I got in hot water at the Lansing Heritage site for having the gall to suggest that JBL compression drivers sound good with Radian diaphragms, Holy Christ, you wouldn't believe the snit some of those guys went into, as though I'd advocated painting over the Sistine Chapel. But the guys that run the site are fine, no heat from them, just from some of the fellas that hang there.
"The brouhaha over at Lansing Heritage Site was basically more of the same - either you agree with the (JBL) company line, or you get invective and personal insults. Questioning the decisions of the JBL design staff does NOT meet with approval."
The only criticism you received was about the application of Aquaplas. You frankly were shooting from the hip and were both incorrect about the best way to apply it and it's effects.
"Questioning the decisions of the JBL design staff does NOT meet with approval"
The bottom line is you didn't know what you were talking about. You were in over your head with an uniformed opinion with no basis in fact. You had no subjective experience and no data to back up your statements. You should just stick to the facts and not cloud them with a smoke screen of made up insults that didn't happen. Just stick with your retraction after Greg's post and please cut the rhetoric.
Considering you are not an active member and do not participate in the Forums over at Lansing Heritage you have a lot of nerve characterizing them in a negative light because your feathers got ruffled.
I don't see one invective or personal insult in the whole thread over at Lansing Heritage. By you characterizing the Forum in a negative light I see your statement as an insult to every participating member on the forum.
http://www.audioheritage.org/vbulletin/showthread.php?t=21529
Rob
The only criticism you received was about the application of Aquaplas. You frankly were shooting from the hip and were both incorrect about the best way to apply it and it's effects.
"Questioning the decisions of the JBL design staff does NOT meet with approval"
The bottom line is you didn't know what you were talking about. You were in over your head with an uniformed opinion with no basis in fact. You had no subjective experience and no data to back up your statements. You should just stick to the facts and not cloud them with a smoke screen of made up insults that didn't happen. Just stick with your retraction after Greg's post and please cut the rhetoric.
Considering you are not an active member and do not participate in the Forums over at Lansing Heritage you have a lot of nerve characterizing them in a negative light because your feathers got ruffled.
I don't see one invective or personal insult in the whole thread over at Lansing Heritage. By you characterizing the Forum in a negative light I see your statement as an insult to every participating member on the forum.
http://www.audioheritage.org/vbulletin/showthread.php?t=21529
Rob
Sorry I'm late ... just read about Magnetar being banned, don't know why, but I think it is a pity.
And re Romy, I've spent some time over at his site, and there is a lot of good information there. One doesn't have to agree on all of it, of course. But some of it makes you think, and that can only be good.
And re Romy, I've spent some time over at his site, and there is a lot of good information there. One doesn't have to agree on all of it, of course. But some of it makes you think, and that can only be good.
Could we please drop the Magnetar issue in this thread? There is another thread started for people to speak their opinions about his removal.
Let's also not let this stray into banter and further accusations. For crying out loud, there are a lot of people who DON'T understand 95% of this thread's technical information, and I am proudly (meekly) one of them. It's Lynn's thread, and he has been more than willing to host and respond to hundreds of people's opinions, questions, and disagreements.
I built his ME-2, and it is without exception the best speaker I have ever heard. Are there better? Of course. Are there better speakers that are horns? I suppose so. Do I want to see his current attempt come to full fruition? YES YES YES.
If you have negative things to say about him, magnetar, gedlee, or whoever else, keep it to yourself. It would be a loss to all of us to have this project get dropped as a result of bickering and swollen egos.
Make your own thread; this is Lynn's. I am thankful he has spent the effort to share his knowledge with all of us. I am thankful for Magnetar's contribution as well. But lately the contributions of a few have turned into ire, with the rest of us noobs having to suffer.
Let's also not let this stray into banter and further accusations. For crying out loud, there are a lot of people who DON'T understand 95% of this thread's technical information, and I am proudly (meekly) one of them. It's Lynn's thread, and he has been more than willing to host and respond to hundreds of people's opinions, questions, and disagreements.
I built his ME-2, and it is without exception the best speaker I have ever heard. Are there better? Of course. Are there better speakers that are horns? I suppose so. Do I want to see his current attempt come to full fruition? YES YES YES.
If you have negative things to say about him, magnetar, gedlee, or whoever else, keep it to yourself. It would be a loss to all of us to have this project get dropped as a result of bickering and swollen egos.
Make your own thread; this is Lynn's. I am thankful he has spent the effort to share his knowledge with all of us. I am thankful for Magnetar's contribution as well. But lately the contributions of a few have turned into ire, with the rest of us noobs having to suffer.
Well, back to the topic at hand. I kind of thought describing my experience over the last couple of years might ruffle some feathers - oh well, just goes with the territory, I guess. It's probably obvious why I do NOT post on the other high-efficiency forums, and restrict my posts to DIYAudio.
Without DIYAudio, I'd go back to lurk-mode, and confine my communications to personal friends (phone calls and e-mails). It's a lot easier that way, since the only time the public sees anything you're doing is when the project is finished. That's the usual corporate approach - a small design group (in hifi, it's typically no more than one or two people), tight secrecy, and then a big PR rollout campaign, with lots of pseudo-AES "white papers" to give the reviewers some useful material to recycle for their reviews. Been there, done that, know how that game is played. Not interested.
Still miss Magnetar, who used a lot less invective (and personal attacks) than I see elsewhere. I agree it is a medium where miscommunication and misunderstanding happen easily. The point is to maximize the S/N ratio, and keep the focus on ideas, not personalities.
Without DIYAudio, I'd go back to lurk-mode, and confine my communications to personal friends (phone calls and e-mails). It's a lot easier that way, since the only time the public sees anything you're doing is when the project is finished. That's the usual corporate approach - a small design group (in hifi, it's typically no more than one or two people), tight secrecy, and then a big PR rollout campaign, with lots of pseudo-AES "white papers" to give the reviewers some useful material to recycle for their reviews. Been there, done that, know how that game is played. Not interested.
Still miss Magnetar, who used a lot less invective (and personal attacks) than I see elsewhere. I agree it is a medium where miscommunication and misunderstanding happen easily. The point is to maximize the S/N ratio, and keep the focus on ideas, not personalities.
Well, This Is Good News
LP's are making a comeback - link here and here.
What isn't mentioned is that modern recordings are NEVER made on the consumer 44.1/16 Red Book format - since the early Nineties, it's been recorded at 96/24, and for modern high-quality releases, 192/24. So even if the sound on the LP's has passed through a digital stage, it'll be originating from a much higher quality source than the Red Book CD format.
LP's are making a comeback - link here and here.
What isn't mentioned is that modern recordings are NEVER made on the consumer 44.1/16 Red Book format - since the early Nineties, it's been recorded at 96/24, and for modern high-quality releases, 192/24. So even if the sound on the LP's has passed through a digital stage, it'll be originating from a much higher quality source than the Red Book CD format.
Recent Measurements
John Atwood has an open-baffle Altec 414Z (similar to my new GPA's) combined with an Altec 288-L and an Edgarhorn Tractrix "Salad Bowl" horn, and he's been getting acquainted with SoundEasy. Here's the impedance measurement of the 414Z mounted in an open baffle - the ripple is at 2275 Hz, well above the anticipated crossover in the 700~850 Hz region. Still, a sharp notch filter might be a good idea - depends on what the acoustic measurements show.
John Atwood has an open-baffle Altec 414Z (similar to my new GPA's) combined with an Altec 288-L and an Edgarhorn Tractrix "Salad Bowl" horn, and he's been getting acquainted with SoundEasy. Here's the impedance measurement of the 414Z mounted in an open baffle - the ripple is at 2275 Hz, well above the anticipated crossover in the 700~850 Hz region. Still, a sharp notch filter might be a good idea - depends on what the acoustic measurements show.
Attachments
Re: Recent Measurements
The 414s can do luscious vocals, you may enjoy them very much.
Here's my Heath AS-21s with double 414s, a little Altec porn for the boys.
Lynn Olson said:
The 414s can do luscious vocals, you may enjoy them very much.
Here's my Heath AS-21s with double 414s, a little Altec porn for the boys.
An externally hosted image should be here but it was not working when we last tested it.
Here's more Altec porn - John's 414Z, 288-L, and Edgarhorn setup. If they sound half as good as they look, we're all set.
The prospect of side-by-side 414's (or 12NDA520's or Lambda's) has been something in the back of my mind all along - true, there might be some issues with horizontal dispersion around the crossover frequency, but the prospect of genuine efficiency above 100 dB/meter is very tempting. There's a certain ease and dynamic reserve that only truly high efficiency systems have.
The prospect of side-by-side 414's (or 12NDA520's or Lambda's) has been something in the back of my mind all along - true, there might be some issues with horizontal dispersion around the crossover frequency, but the prospect of genuine efficiency above 100 dB/meter is very tempting. There's a certain ease and dynamic reserve that only truly high efficiency systems have.
Attachments
Hi Lynn,
I finally did get a chance to do some good measurements on the TD15M. You can see both response and impedance curves here:
http://www.aespeakers.com/phpbb2/viewtopic.php?f=3&t=1677
Response is unsmoothed.
John
I finally did get a chance to do some good measurements on the TD15M. You can see both response and impedance curves here:
http://www.aespeakers.com/phpbb2/viewtopic.php?f=3&t=1677
Response is unsmoothed.
John
John_E_Janowitz said:
Hi John,
I cut-pasted the info on your measurement page below. Are the measurements at 1 inch and 3 inches as you posted or is this a typo for 1 meter and 3 meters? Were you able to make 30/60 degree off axis measurements?
FROM AES WEBSITE
"Here is a close mic response of the TD15M. All data is unsmoothed. The red is close mic at 1" from tip of the phase plug. The yellow is at 3" from the tip. Basically the response is +/- 2.5dB all the way out to 4KHz! With the typical 1/3 octave smoothing most use for their published data, it becomes less than +/-1.5dB over the full range."
Smooth response up to 4Khz? How's that possible? I mean.. the cone is working in non-pistonic region, right? Is it of a special profile?
And what is it with the small bumps in the phase response? At 300Hz and 550Hz?
Thank you.. I think that graph convinced me to take a second look at these drivers. Despite the somehow low sensitivity..
And what is it with the small bumps in the phase response? At 300Hz and 550Hz?
Thank you.. I think that graph convinced me to take a second look at these drivers. Despite the somehow low sensitivity..
LineSource said:
Yes, 1" and 3" is correct. They are close mic measurements, going out far enough in time until just before the first reflection comes back off the floor. I don't have a way to accurately measure response curves at a distance without time gating much sooner. The best I can do in a room with 8ft ceiling is get down to about 500hz before reflections come in. Until I can get some baffles done to go in the garage door and do some 2m ground plane measurements outside, close mic is about all I can do.
SunRa said:
This is a curvilinear profile to the cone. Out of all 3 size drivers, the 15" has the smoothest response up to 4KHz range.
The small bumps in the impedance phase at 300hz and 600hz are due to the corresponding small bumps in the impedance magnitude curve at this point. They are always much more noticeable in the phase vs the actual magnitude. That would probably explain why most don't publish impedance phase plots. These are due to a resonance with the con/surround assembly. I can't remember off hand. They are extremely well controlled though vs the same cone/surround without any treatment.
I'm not sure what you mean by low sensitivity in these. The TD15M is 97.8dB 1w. I wouldn't consider that extremely low by any means.
John