HT SQ ported tuning frequency

[GM]

Greets!

OK, so in theory room gain begins at ~565/13 = ~43.46 Hz, so between this and my experience, a vented 18 Hz Fb is ill advised. Apparently you want a low tuned vented sub no matter what, so if you build a typical cube or rectangular cab, then based on published specs and ~3.83 ft^3 it will need a minimum 46"^2 vent area 65" long to ensure a low vent mach/2 kW and will have to be stuffed to a fare-thee-well since it's so underdamped.

To increase damping/reduce vent length a bit, a ML-TL is much preferred IMO, though more effort to make, so I recommend a ~84.15" pathlength/~78.645"^2 cross sectional area (CSA) folded pipe terminating into a 46"^2 vent 55" long with the driver down ~26.55" from the closed end. Loosely stuff the pipe as required. FWIW, 0.2 lbs/ft^3 sims fine when an 80 Hz XO is factored in.

GM

[kyaloz]

Originally posted by GM
Greets!

Apparently you want a low tuned vented sub no matter what

GM this is not so I did state in an earlier post that I would go sealed if you believe it will yeild better results.

Obviously you are quite knowledgeable and I respect your knowledge.

What I'm saying here is; I want more bottom end bass as the dual 10's don't go low & loud.

The only amp I have is the Gem Sound PA-5505 and the only subs I have areDD9112 & DD9512f


I cannot buy anything else at all, she will shoot me....repeatedly.
So I have to work with these components. If it is going to sound like crap please tell me so but if there is an enclosure I can build that will sound good please let me know.

I am capable of building complex enclosures. I have a workshop and the tools *no CNC router though*

So please fire away with any enclosure type you believe will produce good results, if it is possible with these subs.

[simon5]

GM I took room gain into account with my crazy recommendation. It would be at least 6 dB down at 20 Hz, so back to flat when room gain is taken into account.

[GM]

Greets!

OK, I was in a hurry this morning and didn't 'see' that the 100L/18 Hz design listed in your post was actually Simon's suggestion. My bad. Still, I thought I made it plain that IMO tuning this far below Fs isn't a good plan and that sealed best suited your stated performance requirements.

Unless you have a very 'leaky' room for whatever reason, I still think a digitally EQ'd low Q sealed cab is the way to go, but the well damped ML-TL I suggested looks good in a sim too and if you take a pic of its folded, stepped labyrinth construction, will make for an audio conversation piece. If it has too much gain and/or not enough SQ in-room, then you can either digitally EQ it down or 'stick a sock in it' so to speak to further damp/attenuate it, or just block the vent for a ~IB response.

For sure I do not recommend a typical sub box design though as you will be hard pressed to stuff it enough to damp it down for good SQ due to it being tuned so far below Fs in such an acoustically large Vb (for the driver's compliance).

Trust me, in-room even the sealed alignment will drown out the 10's down low and the ML-TL sims ~87 dB/16 Hz half space sensitive, so with 2 kW on tap your wife may have even better reasons for using you for target practice.

All this assumes of course that the published specs are reasonably accurate and I'm not familiar with this brand, so as always YMMV.

GM

[kyaloz]

Well looks look I'm building a ML-TL enclosure since I can't buy an EQ and the construction sounds interesting!

I am completely unfamiliar with this type of enclosure. Where can I find plans to build one?

[richie00boy]

Don't write off the vented box yet. Whilst it's generally true that tuning or even driving a drive unit below Fs is not a good thing due to moving into the suspension compliance region, with todays high quality drivers with linear suspensions this is not so much of a problem. Indeed, if somebody will recommend EQ below Fs to get low down output, then by the same token you can also vent below Fs.

[kyaloz]

Dammit! j/k

I'm gonna go with the MT-TL enclosure as the construction sounds like a challenge.

Can anyone give me a pointer as to where I find what is involved in the construction of this encl?

[kyaloz]

Originally posted by GM
Greets!

To increase damping/reduce vent length a bit, a ML-TL is much preferred IMO, though more effort to make, so I recommend a ~84.15" pathlength/~78.645"^2 cross sectional area (CSA) folded pipe terminating into a 46"^2 vent 55" long with the driver down ~26.55" from the closed end. Loosely stuff the pipe as required. FWIW, 0.2 lbs/ft^3 sims fine when an 80 Hz XO is factored in.

and

the well damped ML-TL I suggested looks good in a sim too and if you take a pic of its folded, stepped labyrinth construction, will make for an audio conversation piece.

GM

Can someone please show me a pic or drawing of what this looks like. I can understand most of the specs i just don't know the shape of the vent and where the driver goes?

[Notax]

Originally posted by kyaloz
Breaking your house with HT Classic, I love it!!

My room is 4x3m(13'x10') and enclosed, dedicated HT room.

The encl. does not have to be ported if you believe sealed will yeild better results.

The port does not have to be internal. I would make a feature out of it externally.

Also this sub is all I have available to me for a while. If I spend any more on the HT the missus will shoot me.

100L @ 18hz so far, anyone want to second that or beg to differ?

Its small room for deep bass.
For BR I calculate 46 L and Fb=29 Hz. Port diametar 85 mm, 360 mm long. You can go with closed box of 30-31 L (full dampened Fc is around 43 Hz).
Anyway, its best to go with active. You dont have to think about efficient to match with the rest, and you can try different cut off frequncies.

Do not try to built something you dont understand.

Dont let us to persuade you for any design. Make closed box.

[simon5]

http://www.quarter-wave.com/

http://www.t-linespeakers.org/