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Posts by diy speaker guy

I'm not familiar with Dark Matters but I am familiar with that article. It's almost purely fiction and gets more and more fantastically absurd towards the end. It's clear the author of the article doesn't understand the subject matter at all. Take this quote for example - since when is 150 hz considered infrasonic?Here's a more rational look at the facts - http://www.diyaudio.com/forums/subwoofers/236529-subwoofer-too-far-history-lesson.html#post3504399 - read the whole...
I think he's referring to LF roll off in most consumer electronics which is a big problem for a project like this (as per Ricci's post above).
For reference, in post 1 of the diyaudio thread he mentioned a budget preference of $2000 with an absolute limit of $5000 for EVERYTHING. And later on he mentioned that he is strictly opposed to having concrete walls. Also, this is to be built inside a barn, so I'm picturing typical barnboard construction with 1/4 inch gaps between the exterior wall boards and a drywall on 2x4 frame shell inside.I spent quite a bit of time trying to convince him that rigid boundaries...
It's already been asked. (As has every other question you can imagine.)When I suggested he take this project to avsforum I thought he might do that BEFORE we spent a lot of time at diyaudio answering all of his questions, not several months after. Diyaudio has been more geared towards pro style stuff lately so I thought it would be easier for the avs crew to answer the questions about ultra low (single digit) bass, suitable drivers, amps and other system gear, room gain,...
ALL of your questions have been answered already 3 or 4 times at least. Read the post above by Ricci (which has already been addressed several times) and the info below, which I posted in the diyaudio thread back in the beginning of May (which has also been addressed several times), and you will see all the answers you continue to seek. (I added some bold to the last paragraph since you really need to do some research and simulations on your own or you aren't going to...
I did try it. I told you, it agrees (within reason) with WinISD. There's no reason it wouldn't, one is a lot simpler than the other but they are doing the same job.600 watts, 1.8 hz Fb, 1 inch radius, 186 percent mach, or 639 m/s. WinISD says just under 450 for the same conditions. I'm actually surprised they agree so closely since the formula you linked to is so simple and takes only a couple of details into account.Nothing unexpected here. It's a high number, but...
That's just a simple velocity calculator and as such it isn't as accurate as even WinISD's predicted velocity (MJK's would be more accurate than both). Regardless, the results are a bit higher than WinISD predicts but it's pretty close for such a simple formula.WinISD predicts almost 450 m/s from the 2 inch pipe at 1.8 hz but of course nowhere near that up higher, at the beginning of the usable bandwidth where it's 10 m/s.In other words, all the calculators agree (within...
I had a chance to look over the link in a bit more detail. I still didn't get through it all yet but I did notice that the chart you posted is by far the worst looking of the 3. Not trying to imply anything, I assume you posted that since it was the first one of the group, or because it best showed the brick wall effect, but to be fair there's this much more benign chart for comparison. So after doing the math, it seems like the worse chart (as posted by LTD which is...
Again, yes, yes, yes, there will be compression. But I think we are past analogies by now, and using real numbers and graphs. (If you want to continue the analogy though, try sticking a straw in your wife's ear and yelling into it and see what she thinks about your theory.)Those numbers and graphs show 1 db down at 30 hz at 34000 Reynolds, but trend is downward with frequency. I'm not sure how bad it gets with decreasing frequency, it may level off at a certain point...
Ironically, 34000 appears to be right on the ledge before the whole situation takes a dive over the cliff. If my Reynolds number was a bit higher, I'd agree the situation would be hopeless.
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