Its really nice to see your posts again GM. I had started to miss them.....thanks.
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Its really nice to see your posts again GM. I had started to miss them.....thanks.
Quote:
Originally Posted by cradeldorf
With the present xover configuration (with the 1.5mH for LF & 10 mfd in the HF rail), it is in reality crossing over at around 1280 to 1340 Hz, not 1000 Hz. :)
Sorry AA.....pls don't mind
Ok, weather's cold and I've got some 1.5" MDF (or HDF?) that I've been playing with.
GM, can you clarify something for me?
Quote:
Originally Posted by gearfreak
...by this, are we attempting to match the area alone, or also the volume represented?Quote:
Originally Posted by GM
Area alone:
Slot:
~28" x 1" = 28"^2
Round: (6" dia. pvc)
3 * 3 * 3.14 = 28.26"^2
So yes, agreed if matching the area.
But maybe we're also/instead talking about volume... as what I am seeing is that I am getting similar results (down to low 30's) with 2 x 3" ports.
Vol:
Slot: (5/8" = .625")
~28" * 1" * .625" = 17.5"^3
Round (2 ports): (3" dia. pvc)
(((1.5 * 1.5 * 3.14) * 1.5")) * 2 ports = ~21.2"^3
Round (3 ports): (3" dia. pvc)
(((1.5 * 1.5 * 3.14) * 1.5")) * 3 ports = ~31.8"^3
The 3 port option was similar, but not quite as good as the 2 port option. I will have to post the impedance sweeps.
To that end, I had a concept earlier of how to read the impedance sweep, (first peak larger = ___________ , second peak larger = ____________ ), but I've now forgotten and can't relocate the source info.
Anyone have a description of what to expect in a BR in this sense? e.g. (first peak larger = need more port length)
My assumed goal is to get the two impedance peaks to arrive at a like level.
As GM informed me, if the target tuning is Fs, then the old saying is true: "first hump bigger = port too large, second hump bigger = port too small". But apparently if you aren't tuning for Fs, then that doesn't hold true and you'll need a consultation with the GM guru. :)Quote:
Originally Posted by gearfreak
Also should the port never exceed the piston Dia? which is 122 sq in.
Thanks! Ahh. So perhaps that's how I ended up thinking I needed a 3", but longer, single port.Quote:
Originally Posted by Alien_Shore
Great to hear that you seem to be in the "home stretch" with your restoration. Please post some pics when you're done and let us know what drivers you end up using/how they sound/etc......
Me? Hah. no restoration. Just continuous tinkering. :-)
No worries. I've been trying to talk Dennis Had into taking these on to play with the crossovers. Dennis can make a pile of junk drivers sound wonderful, and it's all in the crossover. I can only wonder what he could do with high quality drivers.....Quote:
Originally Posted by cradeldorf
I know the feeling, I just can't seem to ever be happy with the sound. :/Quote:
Originally Posted by gearfreak