home sub/ upgrade help

[larksp]

right now im using a directed compx 5108 10inch in slot port box tuned to 30hz + 500rms bk plate amp

i have as well...... good as new jl10w6v1 think it was refurbished got from the US and not used only to test. it is perfect condition

it will be for movies and some music from tv.... i guess i think i need 20hz do have 5.1

sub right now will chuff i think it is and box vibrates alot on the low end film noises but copes with music fine.......


would be worth making better box ported not slot..... or make a box for the JL but want ported.......

or something new maybe monolith.... but it is 12inch rather than 10. so its fitting it im my room but it is a sub i like..... seen most people say wants 90L more what im worried about unsure port size recommended

i can make the box from mdf.... sure there post for the monolith around for making e.g just 18mm or double up to make thicker

[larksp]

no suggestions from any one ?

[GM]

Got specs of drivers, amp? Max acceptable cab size? General room size, desired sub(s) placement(s)?

[larksp]

the others subs are car ones JL old and 10w6v1 one

th box size is not something i have fort to much off it will depends on what i do and how big it needs to be
amp is bk 500rms 4 ohms one "plate"

i like to see the speaker normally so dont need to be down fireing
what i want to know worth going over to good home sub or will car type sub do for now just new box
room is about
4.5m by 3.5 at a guess

the monolith
Technical Details
Thielle Small Parameters
Sensitivity
86dB
Nominal Power Handling
300W
Weight
2.6kg
Range
22Hz to 500Hz
Impedance
4 Ohms
Qts 0.361
Re
3.7 Ohms
Vas 61.6 L
Le@1kHz
1.30mH
Mms 232g
Fs
23.5Hz
Cms 0.198 mm/N
Qms
2.73
Sd 468.7 Cu Cms
Qes
0.416
Bl 17.46 T-M
Xmax 15mm

[GM]

Well, if you can find its specs, the car audio ones typically have good ones for pipe (aka BIB) or tapped horns capable of < 20 Hz output. For sealed, vented, TL, etc., drivers with an Fs at least as low as the desired cab tuning are preferred, so even 23.5 Hz is a little high for these alignments, though a large vented TL can be tuned down to 0.707*Fs, or ~16.6 Hz if we want.

Officially, DD/DTS requires flat from 20 - 20 kHz from at least the L-C-R channels with an added +10 dB gain 20 - 80 Hz LFE system, but in recent years they've been adding a lot of < 20 Hz tones in movies and a few music DVDs, so folks with the space/$$$ have been installing multiple driver IBs that couple to room gain to make high gain LFE 'room modulators' for when these are included in the soundtrack.

Anyway, this driver ideally needs a passive radiator (PR) due to its low Vas requiring a very large, long vent, so to get around this, a reverse tapered TL (ML-TQWT) will work:

L = 101"
SO = 200"^2
SL = 19.635"^2

All dims approximate. Driver at the closed end (SO), vent at the other end (SL) with light stuffing along its length to as required. Obviously, unless you have high ceilings it will either have to lay on the floor or be folded up as required to fit your space. Apparently it's designed primarily for a small sealed cab and EQ'd as required.

[larksp]

o u seem to know a fair amount.... i can get the specs of the other drivers.. there all over the web

jl is ment to be sealed says jl but not normaly what i like.
and the other fs is high so cant really go below 30hz but i have it in a 30hz slot port....sounds great for music just on some films gets a bit low for it......


the posts for the monolith i have not seen any of them try to use a pr not saying you are wrong though

this is what the site did with the driver

http://www.bkelec.com/HiFi/Sub_Woofe...ithDFandFF.htm

thanks for the post

[AndrewT]

Originally posted by GM
....................Anyway, this driver ideally needs a passive radiator (PR) due to its low Vas requiring a very large, long vent, .........................Apparently it's designed primarily for a small sealed cab and EQ'd as required.

Hi Gm,
could you explain this for me/us?
Vas=60L for a 12inch does not seem unusual.

[richie00boy]

You can't look at Vas in isolation and say the box must be small or a PR must be used. Qts directly influences box size. In this case Qts is 0.361 so a suitable box could be in the 60-90 litre range. So IMO a PR is not really needed, especially if the larger box size is used.

[larksp]

so richie

what do you think i should get a home subwoofer e.g monolith rather than use car ones

[AndrewT]

Hi,
you can use the following:-
sealed box
vented box
dipole
infinite baffle
horn/tapped horn
etc.

Each requires a different driver to get the loading arrangement to work well.
So choose some drivers you can afford and then find out what loading best suits each driver and then whether you can accomodate that box/baffle in your home.

Only after you have excluded the unusable options can YOU tell what is possibly best for you.

eg. if you want small then that forces you down the route of high power handling, high Xmax, extra electronics for EQ, and Qts in the range 0.35 to 0.6