Did ISD Online, Driver and sonotube parameters, now what? (1 Viewer)

[Manuel Delaflor]

I have made calculations for a driver I can get for about 85 bucks. Yes, I would love to get a Shiva instead but for me the cost would be around 200 bucks.
I have a 12" sonotube and the driver I can get mounts on a 11" diameter, so I hope it can be done. Here are the parameters:
_______________
12" unit:
voice coil diameter : 2½
speaker displacement : 1.98 liters
FS: 22 Hz
Qts : 0.355
Qms : 12.880
qes : 0.365
Vas : 176.22 liters
Xmax 17 mm
Revc 3.6 ohms
________________
I don't know how to compare that to those on Shiva (meaning I don't know if it is a bad driver or a comparable one). The volume of my sonotube is 697 liters and the ISD Online Im using is at:
http://www.linearteam.dk/newdriver.html
I filled the driver parameters, selected a vented enclosure and filled the box volume in liters and the tuning frequency was 16Hz
The resultant graph seems good from 20Hz to 50Hz is about -3dB and it have a big bump around the 16Hz of tunning frecuency. The port should be 3" and 27cm long.
Is there something important I have missed? Are my calculations correct and I can expect a good subwoofer??
Thanks to all that have helped me to get here (specially to Jack, which always encouraged me, not that I liked specially, to do all that Im doing now).

 

[Dustin B]

Well first off, the enclosure size you picked is way too big for that sub (697L is more than big enough for a pair of Tempests). I don't think you need to go any larger than 200L for it. And you may want to try bringing the Fb up to 18-20hz.

Next is that Xmax peak to peak or just one way. Also what is the Sd of it?

 

[Chris Carswell]

YOWZERS!!!! 697 Liters!!! Holly shi#!!! Thats like 25 ft^3. You could put 3 18"s in there.
You do want to get your F3 up a bit, I think as well. Try to answer Dustins questions if you can. It will help out when loaded in the program. I will play with the #'s for ya when I get home.

 

[Manuel Delaflor]

That only shows that I did something completly wrong!, because it is not that large by far. It its a 12" sonotube with a height of 39.37" :b Im not even sure that the driver will fit, but I hope that because it is mounted on an 11" diameter.

I can't get any other parameter for the driver, it is a Cerwin Vega HED12.

 

[Chris Carswell]

You must have b/c I get 2.6 ft^3
Use this:
V = Pi*r^2*h
V = 3.14*6^2*39.37
V = 4450 in^3
V = 2.575 ft^3
V = 73 liters

 

[Manuel Delaflor]

WOW How Wrong I was! :b :b
Anyway, now the sub looks awful :frowning:
The only way I have managed to get BASS out of my desired size of sonotube is using the Adire Brahma, either the 10" or the 12". THAT DRIVER IS AWESOME, yes, Im extremely newbie, but I think I already can recognize a GEM. If I use the parameters of the Shiva or the Titanic, for example, my results are also very poor. I know now that those drivers are good for way larger volumes.
To my knowledge, there are no drivers that I can get in here with parameters comparable to the Brahma series So I will remain stuck for a while...

 

[Dustin B]

Not to mention the Brahma is $340-$430 USD depending on size before any tax or shipping.

Can't you go to 18" or 20" sonotube?

 

[Brian Bunge]

Looking at Unibox, this driver in a 150L enclosure tuned to 20Hz doesn't look too bad. The F3 is around 22Hz and you barely pass Xmax (assume 17mm is one way) with 250W. A 200L enclosure gets you an F3 around 19Hz, but pushes excursion a couple of mm past Xmax.

Brian

 

[Manuel Delaflor]

Dustin,
I don't have a place to put a big sonotube, perhaps an 18", if I play with some furniture, but no more. Let's just remember the "wife factor"
Brian,
Thanks! The ISD Online doesn't give that kind of calculation. Anyway, in the graph I can get I see that the f3 is at around 31Hz. I guess that, after all, I can get a good sub out of that driver!
I got more specs, perhaps this can help (the +-0.67 means 17mm one way?):
_______________________
HED-12.0
Fs 22Hz
Qts 0.355
Qms 12.880
Qes 0.365
Vas 6.22 ft3
Xmax (+-0.67") 17.0mm
Revc 3.6(ea.coil)
Frequency Response 20-500 Hz
Power Handling 100 watts ( max 400 watts )
Sensivity 90 dB
Impedance 4

 

[Brian Bunge]

I got more specs, perhaps this can help (the +-0.67 means 17mm one way?):

Yep, that's 17mm!

Brian

 

[Manuel Delaflor]

Brian,

I am confused. If I use the specs of the 8" and 10" drivers from CW I got better results than with their 12" and 15"???

How can it be??? What am I doing wrong?

_______________________________

HED-8.0

Fs 30Hz
Qts 0.540
Qms 5.901
Qes 0.594
Vas 1.07 ft3
Xmax (+-0.47") 12.0mm

HED-10.0

Fs 24Hz
Qts 0.617
Qms 13.600
Qes 0.646
Vas 2.85 ft3
Xmax (+-0.47") 12.0mm

HED-12.0

Fs 22Hz
Qts 0.355
Qms 12.880
Qes 0.365
Vas 6.22 ft3
Xmax (+-0.67") 17.0mm

HED-15.0

Fs 20Hz
Qts 0.516
Qms 10.603
Qes 0.542
Vas 11.68 ft3
Xmax (+-0.67") 17.0mm

 

[Chris Carswell]

The Vas.
The 8" and 10" will play better in a smaller box. Only thing I can come up with.

 

[Brian Bunge]

Manuel,

Define "better"!

Brian

 

[Manuel Delaflor]

Brian,
Apparently it goes A LOT LOWER than the 12" driver! In fact, Im thinking something is wrong because with the 8" driver I see results like F3 of about 20Hz! (in a 79.3 liters enclosure with a tuning freq of 22.26Hz).
I believe it is not possible, but I have inserted the parameters in a program called WINISD beta and in the Internet version. How come an 8" inch driver can give such amounts of bass in a small enclosure and the bigger 12" barely hits around 30Hz in a 110 liters enclosure?
(Am I pathetically newbie?) :b
One thing I can imagine is that the 20Hz will be reach, but with lots of harmonic distortion? or will it be an over excursion of the driver? or, I think this is plausible also, the parameters I found are wrong?
:frowning: Damn, I hate when I don't understand something.

 

[Brian Bunge]

Number one, the 110L enclosure is too small for the 12" driver. Plain and simple. I wouldn't put in anything smaller than 150L tuned to 20Hz. This gives you a fairly flat frequency response with an F3 around 22Hz.

Number two, the 8" driver in the enclosure and tuning frequency you've mentioned looks down right awful! I'm getting a 12.42dB peak at 22.28Hz! That is not what you want. You want a flat frequency response. As flat as possible. You do not want to have a huge peak like that.

Also, I get the idea that you are using WinISD and using the alignments that it spits out as it's "optimum" alignment for a ported enclosure. You need to use your own enclosure size and tuning parameters. Also, if you are using WinISD, make sure you are using the PRO version. It's much better than the standard version. I personally have become quite fond of Unibox. The only downside is that you much have the latest version of Excel.

Brian

 

[Jack Gilvey]

That 10" looks like a pretty bad driver, imo. The low motor strength and very high Qts make it unsuitable for a reflex cabinet. Probably make some kid happy in a car, though.
The 12" looks better with a decent alignment available in 90L tuned to 20Hz. My guess is that that Xmax is peak-to-peak, so there won't be all that much SPL on tap...can't be sure. Looks like it's worth playing with, if just to learn.

 

[Manuel Delaflor]

Brian,

Yes, Im using the "optimum alignment" suggested by the program itself. I downloaded and installed Unibox, I have office 97 but it opened, Tomorrow I will play a bit with it, seems much powerful than WinISD.

I don't have all the parameters that are required, how important is that to the final calculation?

About the peak in the 8" driver, with the parameters I posted, all I get is a flat freq right to around 23Hz, then the F3 is touched ad 20Hz. So perhaps is my program or some parameter Im missing?

Jack,

How can I know if the Xmax is peak to peak or not? all I found is that it is "(+-0.67") 17.0mm"

Using those parameters (90L, 20Hz) I see the F3 is at about 33Hz. I presume Im doing something wrong, but still can't figure out what.

 

[Brian Bunge]

Manuel,

Just input exactly what you have for the specs. That's what I did. And yes, that 8" simulation sounds a bit strange.

BTW, if Xmax is listed as + or - .67", then that would equate to + or - 17mm, or 34mm peak to peak. So maybe Xmax truly is 17mm.

Brian

 

[Manuel Delaflor]

Brian,
I was to update my post, but you already answered!
Anyway, I couldn't get to sleep before playing with Unibox. If I set the parameters I gave you the 8" seems to still beat by a lot the 12" driver!
In a 79 liters cabinet with an FB of 20Hz I get an F3 of 17.70Hz!
I don't know why, perhaps the specs are wrong? or was more the fact that I "invented" a parameter? (the Sd, I also put ZERO on Le, Le2 and Re2).

 

[Jack Gilvey]

How come an 8" inch driver can give such amounts of bass in a small enclosure and the bigger 12" barely hits around 30Hz in a 110 liters enclosure?

"Such amounts of bass" is what the 8" can't give you, it can't move much air. Compare the 8" in 80L with the 12" in 200L. Of course, if 200L is not an option, then the 8" might be fun to play with for cheap, just don't expect too much from it.