DevilDriver

Here is some general info I have gathered in conversation with some speaker engineers. First step is to decide a target. What are you making and how much is it going to cost? What is the margin of profitability? As an engineer, there is an inherent knowledge of working parts. FEA is often used at this point to simulate the end product, as virtually everything can be modelled pretty accurately in FEA if you are experienced with it. At this point, you can achieve simulated small signal thiele/small parameters as well as the BL, Cms, and Le curves of the driver and get a general idea of any thermal power compression that you will experience. This will give you a great idea as to the large signal measurements. Some engineers I have spoken with are extremely concerned with the comparative values of the small and large signal parameters, and as such, all forms of power compression are big concerns. Others are willing to grant that power compression is a tough constant to avoid and will merely accept a certain tolerance. Once the simulated designs are achieved, you can move on to prototyping. From here, there are a number of tests that can be performed, depending on how serious you are: THD and IMD measurements (although use of the GedLee metric becomes more supported all the time), subjective listening tests, and if you've got the wallet, you either send your driver off to Klippel, or you test it on the Klippel machine that you have in-house. This is great for providing a real-world expectation of the level of power compression you can expect. If this meets your requirements, it's on to production. A few production units will be tested as well beyond the normal quality control program. The level at which the power compression is analyzed will vary dependent on the R&D costs you're willing to put in. If your intention is to make a W7, then compression is both simulated and measured (JL is fortunate to be able to afford their own Klippel machine). If you're intending to make the 1000th TC2 variant, you probably won't be too concerned about it based on previous experiences and the relatively low-level concerns that a low-budget driver presents. Of course, I have never personally designed a driver and have only played with FEA minimally as a 1st year engineering student, but this is what I have learned from a select few in the industry. I seem to recall Scott specifically mentioning that he utilizes FEA (and in fact, you will see many speakers marketed as "FEA optimized"), but take my opinion for what it's worth.

Love the jump links. Maybe add some discussion about LMS to the FAQ?

Dude! Sweet...

If looking at the Efficiency Bandwidth Product, the appropriate formula to use is Fs/Qes. Fs already considers the mechanical parameters that using Qts would provide (being that Qes and Qms are the two parameters used to calculate Qts). Additionally, you'll find that Qts always falls extremely close to Qes, there's no real reason to utilize Qts in that formula. As for how enclosure decisions fall into EBP, I would have to argue that perhaps it's time for a new rule. A lot of low Q, mid Fs drivers are proving to be much more versatile than they were ever given credit for. The best thing you can do ultimately is to try your hand at a few different enclosures with any given sub and try to find one that you prefer sonically. If you're anal about sq, you'll likely end back at a sealed enclosure, IB, or OB at some point anyways

I think you will find it a little challenging to have a truly horn loaded enclosure, but a BVR (big vent reflex) should be pretty achievable for you. It maintains similarities in form to a horn but the function is slightly different; vent efficiency is quite impressive. Large format drivers can prove pretty challenging in your average home to achieve true horn loading at low frequencies. Have a look through www.quarter-wave.com and see what you can pick up. MJK's work is not necessarily revolutionary, but highly impressive in that he has taken information interspersed through various knowledge bases and put it all to practical use in a highly accurate enclosure simulation CAD sheet. Also check out www.diyaudio.com for some pretty impressive horn designs; keep in mind that they are primarily limited to midrange or higher use, due to the challenges I mentioned above. To answer your original question, no, I have not, nor do I know of anyone who has. It might be a fun venture though Cheers.

I quickly learned the value of earning interest on your winnings and spending the least amount possible; this leaves you with more money for levels 37, 38, and 39, where you really need it.

Torrent it. It's available on pretty much every private or public tracker. There is of course the free and stellar alternative: http://en.wikipedia.org/wiki/GIMP

It's extremely tough to find the XLS series, but a good alternative is the 830844 from the HDS Exclusive line. For a sub, I agree that the RL-i or CMP 8's would be a great option.

If by talk you mean sex, nice work. Dropped a sausage in her well.

Is it the parsed array keys error? What browser are you using on which IPB style? This is an error that Sean and I worked on with Aaron and found that after viewing someone's profile, IPB added a cookie called "ipb-profile-view" or something like that. This seemed to conflict with the store coding, but once that cookie was cleared, it worked fine. However, I think we were all under the impression that it was fixed. Try clearing your cookies and go at it again.

I love boobs. This one is the most explicit video I have seen on YouTube:

Normally I just scrape off the CA with a putty knife or something similar and it has worked for me on several different speakers. Do you know why the previous coil rubbed? When I hear that, my first concern is that the gap may be misaligned and reconing would you get you no further.

A little under the influence tonight and listening to Floyd, so I felt it was time for a new sig....

Despite what an infamous character may have exaggerated, I'm a big fan of split coil if the OEM is experienced with the technology. Good luck in the future Scott and team! Neil

Greetings Troy. Take some time and post up some of your work!

I hate to draw conclusions where there may be none available, but is it safe to say that your OEM side is the primary contact for split coil designs at this point? Knowing what you did with RE and the use of the split coil on the Poly, can we expect more frequent use of split coil topology in the future? Cheers, Neil

I'm a big fan of the 880. The flexibility and appearance at that price point are hard to beat. I encountered some noise issues in a few vehicles which were quickly corrected by changing ground points.

Welcome to the forum and good luck with the new vehicle. SUV's open a world of opportunities in the SPL world, so I'm sure you'll have fun with that.

I agree so much. Going back through the equations was painful to make sure I was looking at the right part; I greatly prefer doing things in paper. If I get a chance, I'll do up some gifs of the math to make it a tad easier to follow. Oh, and it wouldn't be the first time I calculated things wrong. I did this late at night, so I wouldn't be surprised

Personally, I don't use a carpenter's square. I use a large protractor and a straight edge for every enclosure I do. When I lived on the farm a few years ago, It was not uncommon to find 89* or 91* carpenter's squares, which I really did not appreciate. Use of the protractor is also handy when mapping out a horn. Plus I'm a big dork.

Would be more logical than what they currently have including the new 2. Lord knows that none of the existing sets have enough midbass. Just my opinion, of course

Fuckin eh, man...

Mindless Self Indulgence - Straight to Video

That cone and surround look incredible.

7" mid with ~10mm of excursion and extension over 3khz would be nice.