Welcome to the IHoP

[dem beats 1,223]

Single driver?

Power?

HP, LP, SS filters available?

For starters. 16cuft, tuned to 12.25Hz is about what you cited above. Port air velocity peaks at 10.5Hz at 24m/s which many would say could go higher as it isn't in the acoustic range by 20Hz you are down to 6m/s

Cone excursion also will kill your driver at full power below 10.5Hz, but a simple HP/SS will solve that and could allow you to run significantly more power or a larger box. Secondary peak is 26mm at 18Hz which leaves some room.

118dB out rolling to 113 at 12Hz (no room gain included) but decently smooth response. Some parametric could easily flatten this out and you have excursion room so some sort of processor would benefit the response but could be added later.

PLEASE double check my T/S, this is just what I had put in a long time ago and I never looked to see if it is for your driver, but think so IIRC.

Response curve.

Any possibility of making the port more square? If you could, I would.

5 days off meant busy morning.

OK now I have a moment to think.

Single driver? 1 driver per box. 2 boxes.

Power? 1000. They will get powa from my QSC PLX2 3102

I have the original mael-x with which is SCV but only one pair of posts. Same specs as current 18". Resistance is 3.8 ohms.

So basically the PLX will put 1000 into 4 ohms and 1550 into 2. Basically 1000 watts per speaker.

HP, LP, SS filters available? I have no filter yet just what ever the yamaha z7 will do for me. I am looking for a recomendation as far as that goes.

[dem beats 1,223]

I will get the exact cut measurements tonight. I won't bother with any pics though. I know you guys hate build pics. Takes up too much bandwidth or something.

[dem beats 1,223]

Something really wild was the fact my 4x8 sheets were not 4x8 sheets. they were 4'1"x8'1".

WTF? It was nice being able to get exactly 24" widths I guess!

[///M5 2,833]

The T/S is CLOSE. Not exactly what I have though.

# Fs: 17.4 Hz

# Le: 4.0mH

# Re: 3.8 Ohms (Voice Coils wired in series)

# Qms: 3.62

# Qes: .42

# Qts: 0.37

# Mms: 525g

# Cms: 0.16 mm/N

# Vas: 313L

# Sd: 1182 cm^2

# BL: 22.9

# X-max: 32mm

# Pmax: 1500W

# SPL: 87.8 db/1W/1M

I'm really ticked off that I didn't put any numbers down digitally. When doing my math in my mind here from memory it would be 69, but I know that's not right. I calculated to the nearest .25 of an inch to get the 12hz.

I can't really make the vent any taller....

Or rather I can, but it would require 4 new cut sheets per box basically.... and then a MUCH longer vent due to a big area increase.

Yours have rounding errors, mine are right

I have numbers and models and whatever you need....

[///M5 2,833]

Sean I am missfiring in my brain all over the place. I read what you said as making the 2.5"(H) more and not changing the 24"(W). In case you didn't mean that, I could make the port more square I supose and keep the area the same, I would just not go from left side to right side as a slot port does. I guess it wouldn't affect the chamber enough to make too much of a difference.

Area the same, proportions change

[///M5 2,833]

Single driver?

Power?

HP, LP, SS filters available?

For starters. 16cuft, tuned to 12.25Hz is about what you cited above. Port air velocity peaks at 10.5Hz at 24m/s which many would say could go higher as it isn't in the acoustic range by 20Hz you are down to 6m/s

Cone excursion also will kill your driver at full power below 10.5Hz, but a simple HP/SS will solve that and could allow you to run significantly more power or a larger box. Secondary peak is 26mm at 18Hz which leaves some room.

118dB out rolling to 113 at 12Hz (no room gain included) but decently smooth response. Some parametric could easily flatten this out and you have excursion room so some sort of processor would benefit the response but could be added later.

PLEASE double check my T/S, this is just what I had put in a long time ago and I never looked to see if it is for your driver, but think so IIRC.

Response curve.

Any possibility of making the port more square? If you could, I would.

5 days off meant busy morning.

OK now I have a moment to think.

Single driver? 1 driver per box. 2 boxes.

Power? 1000. They will get powa from my QSC PLX2 3102

I have the original mael-x with which is SCV but only one pair of posts. Same specs as current 18". Resistance is 3.8 ohms.

So basically the PLX will put 1000 into 4 ohms and 1550 into 2. Basically 1000 watts per speaker.

HP, LP, SS filters available? I have no filter yet just what ever the yamaha z7 will do for me. I am looking for a recomendation as far as that goes.

Let me know your exact dimensions and I will ponder what you might need for processing

[///M5 2,833]

Damn liquid creamer is out at the office.

I can't even drink the drip they have here. It has something in it that rips my stomach in half.

We have a few coffee machines here. I have been using the Keurig as of late, with the little Caribou coffee.

Keurig, boo.

Caribou, viva la MN.

[topgun 262]

I had Caribou every day I went to MTS.

[dem beats 1,223]

Sean I am missfiring in my brain all over the place. I read what you said as making the 2.5"(H) more and not changing the 24"(W). In case you didn't mean that, I could make the port more square I supose and keep the area the same, I would just not go from left side to right side as a slot port does. I guess it wouldn't affect the chamber enough to make too much of a difference.

Area the same, proportions change

This would be to make it more rigid and then no need for bracing along the wide port?

If I did this the most simple way it would only add quite a bit of time in the mfg of the window bracing, and I could then keep the external peices the same. I already started some glue work, but the port wasn't part of that.....

What would a few small braces do inside that wide slot port? Tune it a bit higher or do you think it might cause enough turbulance to be audable? I made one calculation I don't like on this box as of now. I cut the bottom pannel short of the 1.5 inch baffle (2 layer of .75 mdf). I planned to just round it over, but now I'm thinking it might be ugly. I could patch the extra 1.5 inches on.

Seeing something like this mocked up with clamps vs on paper is completely different.

[dem beats 1,223]

I think being sick for 2 days, 2 bottles of wine putting me to bed last night, and so much sun and sawdust did something to my brain.

That and this is my first ever from scratch, design and all by me speaker. I can follow cut sheets but this is different. It's a heck of a lot more personal....

It's also easily 4 times bigger than anything I have ever built enclosure wise, and well over 2 times lower tune.

[///M5 2,833]

Ratio's that high (L to W) of a port can cause turbulence which can be audible. Generically speaking a 4:3 is best, but going beyond 7:1 or 9:1 isn't recommended. I hate rules of thumb though so don't quote either, but realize that is what they are and why.

[Penguin4x4 1,761]

mmmm, (mostly) homemade nachos....too much of lazy ass to make my own corn chips ATM...

[///M5 2,833]

<-- needs lunch

[dem beats 1,223]

I skipped lunch while looking at options for me subs.....

Protein shake time!

[dem beats 1,223]

I'm at a 9.6:1 ratio with the 2.5x24.

[///M5 2,833]

I'm at a 9.6:1 ratio with the 2.5x24.

Pretty much. Didn't realize you were attacking this yet. Obviously a day late here. Sorry.

[dem beats 1,223]

in all practical sense I am taking it without the lube?

[dem beats 1,223]

I'm at a 9.6:1 ratio with the 2.5x24.

Pretty much. Didn't realize you were attacking this yet. Obviously a day late here. Sorry.

No need to be sorry. I should have asked this one here a bit earlier....

[///M5 2,833]

in all practical sense I am taking it without the lube?

No, your port is so big it may not matter.

[///M5 2,833]

Again, by 20Hz you are only at 6m/s. Many anal people will tell you to stay below 12 there

[///M5 2,833]

I'm at a 9.6:1 ratio with the 2.5x24.

Pretty much. Didn't realize you were attacking this yet. Obviously a day late here. Sorry.

No need to be sorry. I should have asked this one here a bit earlier....

Or at HAF

[///M5 2,833]

HAFTOP

[dem beats 1,223]

I was kind of going off what sandt said over at HAF. Not to throw him defenseless under the bus, as it made logical connections in my mind with what I have done before smaller scale.

dem beats, on 14 May 2010 - 10:33 AM, said:

So in truth if I have "enough" port area in a slot port I don't have to worry about a minmum hight of the slot port?

Correct. Just be sure to round sharp edges (it doesn't need to be massively rounded, just knock the edge off of it) to reduce turbulence. An inch or 2 is perfectly fine. When I built a ported cabinet for my Brahma I used a 1 1/2" wide slot port with no issue.

And the box I was thinking originally

Easy Button End Table MAX 26.5" x 24" x 37.5" hwd - AVS Forum

His port looks effed though with all those LOOOOOOooooong braces in there. His area would be a bit less than minimum from what I was calculating, but he would be flat on the 9:1 ratio of H x W

[///M5 2,833]

Really it shouldn't be bad, it isn't terribly off.

[dem beats 1,223]

Other than just laying another sheet of MDF on the external wall of the L port could I create a grid of bracing? That would then make it so I don't have to add turbulance to the port?

I suppose just adding another sheet of MDF would be the easiest, but would it be the best?

Sticking on some 2x2's is always an option.