Rockford vs JBL vs Soundstream

[zafira1981]

Hi,

I want to build a sub-woofer for my HT. My appartment room is small (3m x 3.5m). I think that a 10" sub will be good enough.

Looking what is available in my country I found these three speakers:


Rockford PS1410 (u$s152)

JBL CS10 (u$s54)

Soundstream Xstream XS10 (u$s146)

I know that car subwoofers are not the best, but I cant afford a REALLY good subwoofer.

I think that rockford will be the best, what do you think?

[chris661]

I would try to get a home theatre subwoofer, as car subwoofers aren't as good for HT use.

And I have a room similar size - I recommend an 8" driver - there's also more choice.

What box size can you have?

The rockford models well at 101 litres, tuned to 23Hz.

[zafira1981]

Thanks for your advice.
Looking around I found this one of 8" at a relative good price

JBL GTO 804

diameter: 8"
Fs: 25.6hz ()
Qts: 0.56 ( )
Qms: 6.15
Qes: 0.61
SPL: 93dB
xmax: 9.5mm
Vas: 166 (is this ok?? for a 8" speaker??)
BL: 10.88T
300W RMS, 2x 4 ohms

[zafira1981]

Sorry, I have to re-post because the small signal parameters were wrong in the page that I looked. From the PDF,

Fs: 29.6
SPL: 91dB
Qts: 0,42
xmax: 11,5mm
Vas: 16,42l
BL: 12.88

[RobWells]

Originally posted by chris661
I would try to get a home theatre subwoofer, as car subwoofers aren't as good for HT use.

A driver is a driver. How you use it depends on your own applications. Many car drivers seem to be perfect for tapped horns according to the guys in the tapped horn thread and Tom Danley who used them in several of his own inventions.

Can't understand why you'd suggest an 8" sub over a 10" ?

My advice to Zafira is to download winISD enter the various subs he has available into it and model each one against the other.

Also model one of the well recommended drivers such as a shiva or tempest and compare the curves to the drivers he has available.

For example the JBL GT4 'car' sub matches the response of the Adire Tempest 'home' sub right down to 18Hz, in a box half the size ! (I wonder how 2 of the 12's would compete against 1 of the 15's in similar sized boxes....)

[zafira1981]

Rob, I think the same than you, a driver is a driver.

I'm surprised about the results of the simulation with WinISD and the 8" sub. Are my calculations ok???

I put in the same graphic the screenshot with BOX tab and VENTS tab.

[zafira1981]

simulation with three diferent speakers that I can buy:

1: Rockford Fosgate 10", 152usd, 150W
2: JBL CS10 10", 53usd, 100W
3: JBL GTO 804 8", 130usd, 300W

It seems that the 8" GTO is performing much better than the rest!

[RobWells]

Try tuning the JBL lower down, maybe around 18Hz. Will give a smoother curve. In the signal box type in the max wattage you think the driver will get and model the vent to have a low enough mach at that power.

I haven't got the jbl's specs in my winISD database so cannot put a screenshot up right now.

Cheers
Rob.

[zafira1981]

In the signal box type in the max wattage you think the driver will get and model the vent to have a low enough mach at that power.

I cant find the "signal box" that you're talking about. Maybe because I have WinISD Beta 0.44 and you have a newer version?

With 18hz, i have a smoother response but -5db@20hz

In the attach, I put the t/s parameters of the speaker.

I really apreciate your help

thanks,

Jorge.

[RobWells]

Hi again.

I'd still go for the biggest driver you can get that models well.

Here's a pic of the CS10 how I'd do it.

You can see the version of winISD I'm using at the top, and also the signal tab on the right hand box. You can enter the power applied to the driver and watch the mach change in the 'rear port velocity' window.

Have a search on 'room gain' to see why it's not bad to have a falling response, especially in a small room.

Rob.