And the vent position
In a Met vent is assummed to be out the bottom.
So a Met is defined by start area, end area, length, driver offset, and vent size.
dave
Imnsho it is more polynominal. If the top and bottom are square then it is exponential.
Quadratic does increase at a rate slower than linear where in the metronome it increases at a rate faster than lineair. A Voigt increases at a linear rate.
If you look at the graph posted by Planet10 a couple of posts back, you'll notice that the rate at which the cross section increases at the beginning is actually slower than linear, but then ends up expanding at a higher rate than linear.
For all intents and purposes and without going into the intricate mathematical details (the last Math course I attended dates back to 15 years now
) this can be approximated to be a quadratic polynomial.
For all intents and purposes and without going into the intricate mathematical details (the last Math course I attended dates back to 15 years now
I did derive the expansion formula and it is a quadratic.
dave
FE208 Sigma
I need to take my main speakers out of action for a while and need to whip up some instant replacements - I have the it's either metronome or open baffle.
Dave, do you have these numbers for the old Fostex FE208Σ (just sigma - pre "E")
I need to take my main speakers out of action for a while and need to whip up some instant replacements - I have the it's either metronome or open baffle.
No, but i'm sure there must be someone around with Martin's sheets that can sim one.
dave
Wow, still talking about this. It's like I never left.
Anyway, my kids are all off to college in a few weeks and I'll have an empty house. In order to keep my sanity, and to keep myself from killing my wife, I figure I need a project and this might be it. I bought a pair of Fostex 126E from a member here 3 years ago, just about when I stopped doing all things audio except enjoying what I have. I tried them in my cardboard Mets that I made for a pair of Radio Shack drivers (not the ones that everyone uses, but still sounded pretty good), but I didn't like the sound with the Fostex at all. And there they sit, in a corner in the cardboard enclosure, unused for 3 years now. I figure I'll try again with a real box.
I plan on doing this with leftover "engineered" wood flooring, basically plywood with a good layer of hardwood for the exposed part. It may be thinner than the recommended baltic birch, but I have it on hand. I'm hoping I have all materials on hand, even leftover speaker parts. For the top and bottom cap I was thinking MDF so I'd have something solid to hold it together. Will this ruin the sound? I'd put a piece of flooring on the top to finish it. The edges are a problem since they will be exposed and I doubt I'll find any kind of matching tape or veneer.
Oh, everyone was always astounded with the sound of the cardboard mets with the RS drivers. An eerily pure sound when the flimsy box wasn't buzzing. Great for girl and guitar music, but leave the bass and drums home.
Anyway, my kids are all off to college in a few weeks and I'll have an empty house. In order to keep my sanity, and to keep myself from killing my wife
, I figure I need a project and this might be it. I bought a pair of Fostex 126E from a member here 3 years ago, just about when I stopped doing all things audio except enjoying what I have. I tried them in my cardboard Mets that I made for a pair of Radio Shack drivers (not the ones that everyone uses, but still sounded pretty good), but I didn't like the sound with the Fostex at all. And there they sit, in a corner in the cardboard enclosure, unused for 3 years now. I figure I'll try again with a real box.I plan on doing this with leftover "engineered" wood flooring, basically plywood with a good layer of hardwood for the exposed part. It may be thinner than the recommended baltic birch, but I have it on hand. I'm hoping I have all materials on hand, even leftover speaker parts. For the top and bottom cap I was thinking MDF so I'd have something solid to hold it together. Will this ruin the sound? I'd put a piece of flooring on the top to finish it. The edges are a problem since they will be exposed and I doubt I'll find any kind of matching tape or veneer.
Oh, everyone was always astounded with the sound of the cardboard mets with the RS drivers. An eerily pure sound when the flimsy box wasn't buzzing. Great for girl and guitar music, but leave the bass and drums home.