Hi,

Im trying to design a box for my sub from some WinISD graphs.. but as this is my first time at this I'm not sure what sort of graph im really trying to acheive... or how close the graphs are to real life output.

Basically... does anyone have a copy of a graph from winISD that would give good real life SQ performance (low sub bass, musical, fast/punchy techno bass).

Something that I can try and aim for.

Cheers
Jason

Well, what I try to look for when modelling a sub in WinISD is a flat graph, that'll play as low as possible, but keeping in mind that you want as low group delay as possible (generally dont want anything above 25ms, unless it's under 20hz or so).

What is a good -3dB freq to acheive?

I listen to rap/hiphop/dance/techno/breaks....so I'd prefer to be able to reproduce some of that killer low end bass. Trouble is... when I try to get down to less than 30Hz... the graph starts getting a bit sh*tty .

I don't mind having the output response FLAT... even if its slightly less than 0dB attentuation - I'll just turn up the gains - sensibly.

But I do want low end response and low group delays :?.

My T/S Specs are
Qts=0.3
Vas=90.6L
Fs=27Hz
Qms=5.0
Qes=0.32

Its a 9122 Eclipse Ti.
..I think this is all thats needed.

I've been comparing against specs for a Boston G512 SVC(4Ohm).. and the boston kicks its ass (in a big box)
Boston T/s:
Qts=0.58
Vas=74.5
Fs=29.65
Qms=9.94
Qes=0.62

The boston certainly does look the better of the 2 subs on paper, but it doesnt require as large a box as you may thing.
It looks like it gives a much flatter in car response with a 40ltr box, then with a bigger 100ltr box.

Ofcourse this is only on computer, not in practice, but i'd have a stab at saying anywhere between 40-80ltrs would be sweet for the boston.

Thanks fury. But i dont wanna hear anymore positive comments about the boston!.. (cause I already bought the Eclipse :?).

Good work on my part... doing the sims after buying the gear :?. but I have my reasons.

PS> I was looking at the eclipse in a ported box... because for a sealed box (12.3L), isnt a -3dB point @ (66hz) too high.
..making the box bigger doesnt seem to do much to improve the graph really either :?

Problem is.. im designing a box to a "graph"... not a box to a "sound" .. I have no idea what a "good sounding box in a car".. looks like on WinISD...

But going on the G5 specs in a 76L sealed box..38Hz @ -3dB.. kills the eclipse .
But its a very gradual roll-off - im led to believe this isnt very desirable.

I really dont have that much space to use for a box anyway... probably under 60L.. but until I find out exactly how much... I'll leave the box sims for another time.

Thanks for ya help fury
Jason

..Not gonna be happy if I shoulda gone Boston instead of eclipse!

30ltrs tuned to 30hz for the eclipse sub gives a -3db around 20hz, which'd be sweet for sq. group delay also stays below 15ms down to 20hz.

Should be fine if you can make it.
Otherwise 30-40ltrs sealed, gives a 3db slump around 60hz, but otherwise is pretty flat in car.


If you don't want your sub, you can gladly offload it to me for cheap

lol @ the sub offload..
I guess if you give me the right help I wont need to offload it.. - "CONFLICT OF INTEREST"

I'll check my ISD's .. my results are WAY diff.. to yours :? .. i must be doin something wrong.

Thanks

I think i got it working.... was using WinISD standard...Now using PRO alpha.. graph looks much better

I'm thinking of either a:
Ported QB3 - Quasi butterworth Box with 55L, tuned to 36Hz
OR
Ported QB3 with 84L, tuned to 31Hz.

Not sure which would sound better in car.

Fury - if you can be bothered can u verify what I sim'ed.. and gimme feedback if you see a better alternative

Cheers
Jase

Here...
The second one is incar response.

Thanks for that mate

Your graphs looking something like that?

Maybe I should model something crap and pretend it's your eclipse sub, then you'll offload it to me cheap

Here are my graphs.

There are 4 diff. boxes shown:

Pink - 55L/36Hz Ported
White - 84L/31Hz Ported
Green - 95L/28Hz Ported
Yellow - 13L sealed

.... Any advice on which graph for a box would sound better in car?
... Anyone used the same driver? (Eclipse SW9122)

Personally i'd go for 35ltrs sealed as said above, but depends what you're after and how much boot space you have left. Either that or 30ltrs tuned to 30hz if you really want to go ported.

Ultimately, best way is to make a box and see how you like the sound of it

Maybe make the 35ltrs sealed, see how you lke it...
If you want more output, then wack in some bodgy port and make it ~30ltrs tuned low... 30hz or lower if you dare.