Beyond the Ariel

Re: Re: OSWG BEM simulation

gedlee said:
Thank you very much for this. From your data I am assuming that the mouth of this waveguide would be 10", my smallest. I have data for this device and I will post it as a comparison, but I should also say that this waveguide is the worst of the bunch being just too small. The 12" and 15" devices are much better.

It was actually supposed to be the 15" version, but I may have misunderstood something. I took it that the radiused mouth ended at 15", but if it is the diameter of the waveguide before the radiused mouth that set the quoted size, then this would be a 11" WG.

gedlee said:
But at any rate I'd have to say that you have achieved all of the pertinent features that I find. First the constant directivity, and the -6 dB / oct HF loss is typical. The lowest resonance peak is "tamed" by the HP filter and the next one, which I don't typically see this strong (but I use foam remember) needs a second tank circuit to control. The hole on axis is now quit accurate.

I'll dig up my data and post it.


Good to see that the simulation came so close. As you say, some of the differences between measurements and simulation is likely to be because the driver parameters are off.

Bjørn
 
Re: Re: Re: OSWG BEM simulation

Kolbrek said:


It was actually supposed to be the 15" version, but I may have misunderstood something. I took it that the radiused mouth ended at 15", but if it is the diameter of the waveguide before the radiused mouth that set the quoted size, then this would be a 11" WG.

Bjørn

Bjorn

Yes, my "specs" refer to the waveguide mouth diameter before the radius. The 15" is actually 18" across, etc. So what you did was closest to a 10" whose data I showed.
 
No, strangely enough I can't see the image in your post. I can see the frequency response plots in post #4706, and images in earlier posts too, but not this last one.

Checking... I can see it with Internet Explorer, but not with Firefox. Odd.

Saving the file from IE, it has a *.wmf extension. That may be the reason Firefox doesn't display it.

So now I got it, thanks!

Bjørn
 
New Dipole Drivers on their way

John J of AESpeakers sent an e-mail telling me that the Dipole15 variants are on their way. Here are the measured parameters of the new drivers:

Fs: 33hz
Qms: 31.28
Vas: 325L
Cms: 0.31
Mms: 75g
Rms: 0.49
Xmax: 9mm
Xsus: 10mm
Sd: 855 sq. cm.
Qes: 0.98
Re: 3.1ohm (parallel)
Le: 0.058mH
Bl: 7Tm
Qts: 0.95
1W SPL: 92.75dB

Since the drivers were fresh off the line when measured, after break-in the compliance should increase a bit, which will lower Qts and and Fs in turn. (Not much, but some.) Sonically, they should be similar to the TD15M's, with the TD15M extended pole piece, cone, spider, suspension, and underhung voice coil.

Although I plan to use a quartet of these drivers for the OB bass modules (covering the range between deep bass and the dipole peak of the 12" driver), the smooth response (extending out to 5 kHz) should make them suitable for a simpler OB system that uses one or two of these Dipole15 variants and a HF driver above.
 
Sorry for the long delay in posting. I've been steering the good ship SS Retirement in heavy seas, and it has taken my full attention. Here are some items I've come across that shine a little light on what's been happening:

The End of Wall Street
A real eye-opener - I didn't know, for example, that the securities-ratings firms were engaged in massive fraud, routinely re-rating junk-grade mortgages from BBB up to AAA, re-packaging and re-selling them to unwary institutional investors, and clouding the paper trail back to their real origins. This article, although dense, is a must-read for background on what's happened in deregulated financial markets over the last twenty years.

The chart below is from Calculated Risk, one of my daily-reads. I don't personally think we're headed for a Great Depression, but the economic data isn't pretty. If one or more of the Detroit automakers fails, the descent (in the real economy) will steepen.

The real question is where the market bottom is - right now, in January, or some time later in 2009. One ray of light from the recently concluded G20 conference is the agreement on the need for worldwide economic-stimulus programs, preferably in large-scale infrastructure improvements. With any luck at all, the turnaround could be very rapid - there's 12 trillion dollars sitting on the sidelines (parked in T-bills) waiting for conditions to improve. This money will move very fast once the credit markets clear and real economy shows signs of turning around.

My tiny little contribution to the audio-infrastructure goes forward - fortunately, the recent purchase of the quartet of AESpeaker drivers completes the big-investment part of the project. The rest comes down to baffle-boards and measurements.
 

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Well, if there's any upside for audio, it's that the boutique market of fashion-driven audio (buying insanely expensive stuff to impress your neighbors) will finally disappear for good. What we'll be seeing will be the re-emergence of value; people will be looking for long-term satisfaction and real engineering instead of flash and glitz. This is what the audio market did during previous sharp downturns, and it should happen again.

There has been a tremendous amount of corruption between the "gatekeeper" audio-reviewer magazines/websites and the "inner circle" of high-profile manufacturers (not surprisingly, dating back the Eighties), and this market event should clear it out, as it will clear out the corruption in the financial markets.

I expect the "straight shooters" who have avoided the boutique world of the extreme high-end will survive, thanks to customer loyalty and word-of-mouth. What will disappear will be the soap bubble of image, glitz, and bought-and-paid-for magazine reviews touting the latest $60,000 product-of-the-month. I don't think we'll be seeing any more $5,000 cables, $20,000 CD players, or $150,000 loudspeakers.
 
diyAudio Member RIP
Joined 2008
John_E_Janowitz said:
Roger Russell from McIntosh had told Nick that the best midrange material he had ever heard was the Kapok. This is what we experimented with in our 6.5". We found it to be much more well damped than the standard pulps of today.



I remember that day like it was yesterday, sipping lemonade in his living room as he did the first frequency response graph ever taken of a Lambda motor speaker prototype. Its been nearly 10 years but we finally got to put this tidbit of info to good use.
 
John_E_Janowitz said:


We've built a few. Jeff Bagby just received one and will be getting some info back to me soon. He is planning on using it instead of the PHL for the new Salk open baffle midrange speakers.

Here is the news release page on the 6.5" and there is a link to our forum with parameters and curves at the bottom.

http://www.aespeakers.com/news.php?start=0&news_id=16

John


Nice work gentlemen!
http://www.diyaudio.com/forums/showthread.php?postid=1545180#post1545180

http://www.diyaudio.com/forums/showthread.php?postid=1545434#post1545434
 
Re: New Dipole Drivers on their way

Lynn Olson said:


.... Here are the measured parameters of the new drivers:

Fs: 33hz
Qms: 31.28
...
Qes: 0.98
Re: 3.1ohm (parallel)
Le: 0.058mH
Bl: 7Tm
Qts: 0.95
1W SPL: 92.75dB

....

Thanks a lot for sharing. And the Qms of 31.28 is amazing! What a low loss suspension! But why does TD15M come with 5.09? Are they using different formers?

And, it seems the efficiency is not high:( (or, it gets another 3dB by 2.83V but still about 2dB shy.... )

Is this for the high Qes setting? Would it be nice to lengthen the voice coil a little bit (shorten the Xmax, enlarge the BL) to bring the Qts down to 0.7?
 
john k... said:
Please, we don't need a pep talk.

Lynn Olson said:
The chart below is from Calculated Risk, one of my daily-reads.

Thanks for sharing this plot, Lynn – nothing could proof any better that market crashes are intrinsic part of today's "science of economy".

Personally I find if interesting that nobody seems to be demanding US – as the arguable causer of national and individual disaster and suffering of many many people around the globe - for any refund - at least I haven't heard G20 people discussing this idea of closing the feedback loop (action / reaction).

I don't speak of shareholders losses mind you – but those who don't know how to pay their bills being unemployed overnight (and the classes below) or even completely ruined nations like Iceland.

In my understanding "science of economy" boils down to the widely accepted "believe and desire" that many have to suffer for the pride of few (naive hoping *me* becoming one of the few).

Something to think about in times like that – when everybody blows the horn of "we have to restore *faith* into economy" - *and* we have to be aware that there are a multitude of economic models to think about not necessarily only the one ruling the world today.

If *freedom for the world* is proclaimed – it's always meant also for freedom of economy (even outright ripping others ) kind of wild west behaviour left over from old times where peacemaker mentality was the basic rule and this kind of *freedom* was high in the list

Just my two cents – though I know that mods don't like postings alike here

Michael
 
Lynn Olson said:
Well, if there's any upside for audio, it's that the boutique market of fashion-driven audio (buying insanely expensive stuff to impress your neighbors) will finally disappear for good. What we'll be seeing will be the re-emergence of value; people will be looking for long-term satisfaction and real engineering instead of flash and glitz. This is what the audio market did during previous sharp downturns, and it should happen again.

There has been a tremendous amount of corruption between the "gatekeeper" audio-reviewer magazines/websites and the "inner circle" of high-profile manufacturers (not surprisingly, dating back the Eighties), and this market event should clear it out, as it will clear out the corruption in the financial markets.

I expect the "straight shooters" who have avoided the boutique world of the extreme high-end will survive, thanks to customer loyalty and word-of-mouth. What will disappear will be the soap bubble of image, glitz, and bought-and-paid-for magazine reviews touting the latest $60,000 product-of-the-month. I don't think we'll be seeing any more $5,000 cables, $20,000 CD players, or $150,000 loudspeakers.


Hi Lynn

Sorry to bounce in at this point, but I've just become the owner of an incomplete Ariel project which I hope to complete.
I can't help but agree with you re the insane prices for kit the majority of which don't warrant the price tag or the +ve reviews.

Hence the look of horror on my friends faces when I mentioned building the Ariel and junking my current set of speakers, the advantage for me being that I've auditioned a completely built pair of Ariels.

I dare say completing the build is going to be an experience for me, but what have I got to loose.
 
Lynn Olson said:
Sorry for the long delay in posting. I've been steering the good ship SS Retirement in heavy seas, and it has taken my full attention. Here are some items I've come across that shine a little light on what's been happening:

The End of Wall Street
A real eye-opener - I didn't know, for example, that the securities-ratings firms were engaged in massive fraud, routinely re-rating junk-grade mortgages from BBB up to AAA, re-packaging and re-selling them to unwary institutional investors, and clouding the paper trail back to their real origins. This article, although dense, is a must-read for background on what's happened in deregulated financial markets over the last twenty years.

The chart below is from Calculated Risk, one of my daily-reads. I don't personally think we're headed for a Great Depression, but the economic data isn't pretty. If one or more of the Detroit automakers fails, the descent (in the real economy) will steepen.

The real question is where the market bottom is - right now, in January, or some time later in 2009. One ray of light from the recently concluded G20 conference is the agreement on the need for worldwide economic-stimulus programs, preferably in large-scale infrastructure improvements. With any luck at all, the turnaround could be very rapid - there's 12 trillion dollars sitting on the sidelines (parked in T-bills) waiting for conditions to improve. This money will move very fast once the credit markets clear and real economy shows signs of turning around.

My tiny little contribution to the audio-infrastructure goes forward - fortunately, the recent purchase of the quartet of AESpeaker drivers completes the big-investment part of the project. The rest comes down to baffle-boards and measurements.


Appreciate your views on this Lynn, and sharing your pain.
 
Lynn

I could ramble on for days about this, but let me just give you my "insiders" perspective on the Auto Crisis.

I work in Automotive for more than 20 years. It had its ups and its downs, but in the last years that I was there, about ten years ago, it was all down. At one point every single manager that I had any respect for had quit to go elsewhere and the company was rewarding anyone who promised success. It didn't matter if this actually happened or not, all that as required was "a positive attitude" (delusional), a team player (willing to lie to others telling them what they wanted to hear) and an "entrepenuer spirit" (a real A-hole). When I left Ford (Visteon actually) there was no one arround me (managers that is) thats seemed in the least bit competent and there was a lot of friction between what I saw as the future and what they were "selling". I had to go.

Much as I know how painfull it would be, I really think that bankruptcy is the best option for the car companies. Thats the only way that they are going to fix the ills that plauge them. A bailout would only prolong the problem, it won't solve a thing.

I remember Lidia (my wife, PhD, Department Chair at a local university) being irrate when she learned that a factory worker at the auto companies, with overtime, would make more than she or anyone else on her staff. If THAT'S not a problem what is? And health care - while all else is collapsing here in MI, the hospitals are all building new facilities and booming. And how are they doing that - Auto health insurance that subsidizes the outrageous and growing health care costs.

We are in for a sad time of social reordering.