Clarity on Seas Thor Kit

[Scottmoose]

The Fat Thor with a downward firing port should rock the foundations. In MathCad, the response appears to droop a little -that's delibarate because the current version of the software doesn't account for the massive boost from the floor and vertical room-mode. One tweak however -go for a 4" x 4" port rather than the 3" x 4" one I originally suggested -I've been re-working it a little, trying to get the speaker to roll off (ha!) in lock-step with room-gain. Smooths things a little. If anyone finds they want a little more lower end (possible I suppose ;-) try using a higher resistance wire -Van Den Hul carbon if you want 'audiophile' stuff, 18AWG magnet wire or the ilk should do just fine.

I've re-checked Short Thor too, just to be sure, as my original calculations were a little rough around the edges: this is the response of the cabinet as drawn by Dave (great stuff!). Doesn't go quite as low as Fat Thor, which will embarass some subs I can think of, but low enough, and it's somewhat smoother / more refined. More 'hifi' I suppose. Your choice!

Best
Scott

[jackinnj]

I may be able to have the cabinets CNC routed and laminated -- would certainly be too heavy to ship to South Africa or Europe but U.S., Mexico and Canada might work.

[DJNUBZ]

If you can get the enclosures CNC cut and shipped for a reasonable price I would be intrested.

[troystg]

Originally posted by jackinnj
I may be able to have the cabinets CNC routed and laminated -- would certainly be too heavy to ship to South Africa or Europe but U.S., Mexico and Canada might work.

Well Madisound charges ~$600 and if I were to make another pair for Repute I'd charge him $1,000,000!.

To get a set CNC milled and laminated for a reasonable price would be well worth it!

"If anyone finds they want a little more lower end (possible I suppose ;-) try using a higher resistance wire -Van Den Hul carbon if you want 'audiophile' stuff, 18AWG magnet wire or the ilk should do just fine. "

So exactly what will adding a little resistance to the lowpass do? Smooth the response, extend the lowend cut off, steepen the rolloff?

[Byrd]

LOL - Mmm yeah South Africa. I paid about $200 dollars shipping for my drivers.

With that kind of money it wont take long to cover the cost of my own CNC machine.

Besides I already have an HNC system

[Scottmoose]

Forget I mentioned the 4" x 4" port for the Fat Thor -mere blithering (I made a typo when entering the parameters and didn't notice -humble apologies. The original 3" wide x 4" long port still stands as probable optimum for this configuration)

Higher resistance wire = ye olde trick pulled by us full-range driver types. Raises the Qes a little, just enough to pull the bottom end into line -if you have a shallow rising response, or a gradual roll-off, it usually flattens it out. For example, I use 24 AWG magnet wire with a pair of Fostex FF165K drivers in one of my completed projects -a very large TQWT. Those cabinets will have a pair of FE166ES-Rs in them next weekend -with those, I'll probably shift even further to using 30AWG. Frankly, the difference will be marginal with the Fat Thor, as they don't start rolling off until below 40Hz anyway, so don't pay too much attention to it. Just a throw-away remark, so to speak. Something to experiment with in future if you feel so inclined, and a -8db point of 20Hz isn't quite good enough any more ;-)

By the way, you can chop the port of Short Thor down a little to 4". Makes the roll-off a little more uneven, but the general response is even flatter over 100Hz (you'll need to add 6db overall for the paralleled drivers to this graph -it doesn't take that into account like the one above)

[Scottmoose]

Final tweaks before I bow out. If you find the response of Fat Thor too droopy (though the floor-mounted port should utterly eliminate that -I deliberately kept the anechoic droop because of this) then increase the area of Sm to 1.75Sd, decrease the length of the vent to 2" and increase its diameter to 5". Props it up a bit more, but retains a bit of a decrease to take the port position into account.

Short Thor is my favourite though. I wanted to tweak it fractionally: all it needed was another vent mod. 4" wide, 4" long. Best response from these drivers. F3 33Hz, one of the flattest responses I've ever seen from anything. It hardly needs any stuffing at all -at a pinch, you could do without completely. 0.5Lbs ft^3 is more than enough

Regards to all & good luck with your various Thors
Scott

[Byrd]

Originally posted by Scottmoose
Final tweaks before I bow out.

Yah right we believe you. Just as soon as my material has been cut you'll come up with some new brainwave LOL

Thx for all the sims Scott. It looked pretty complicated to use MK's sheets. Is there a dumb users guide to using them? A sort of practical tutorial? If not - maybe there is a gap that needs filling, nudge - nudge wink wink.

[johngalt47]

I agree with Byrd. I tried using those spreadsheets but could never make them come out the way I wanted.

[Repute]

With Thanksgiving, and getting over a nasty cold I have not done any stuffing adjustments.

The original design called for the following:

"400 g (14 oz) of the damping material should be placed in the front channel; 250 g (9 oz) in the rear."

If I recall correctly, Scottmoose indicated the Fat Thor would use the same? Please correct me if I am mistaken.

Thanks!
Rep