Maz
Dec 27 2003, 03:47 PM
Using WinISD, the bigger box that is tuned lower provides more deep bass with the same power than a higher tuned.
Is this because the box makes the sub move further at the same power, or is it the ports producing the extra volume?
Im aware that the sub moves less in a ported box than sealed, at the same power.
Also if i tune high at around 40hz would i actually witness increased excursion as the sub is not supported under the tuning frequency. So as i have no subsonic filter this would be bad?
[ December 27, 2003, 13:49: Message edited by: Maz ]
Wrayza
Dec 27 2003, 05:22 PM
A sub in a ported box will move more than the same sub in a sealed box with the same amount of power because of a less resisting force behind the sub, not the other way around
GIMPY
Dec 27 2003, 09:05 PM
Get BassBox 6 Pro, it makes WinISD look like junk.
If you know your subs rated RMS power / X-max and a few other T/S specs it can plot the subs excursion over power/frequency, along with other useful information like Vent Air Velocity over power/frequency.
Top program
Bassaholic
Dec 27 2003, 10:03 PM
QUOTE
Originally posted by Wraybees:
A sub in a ported box will move more than the same sub in a sealed box with the same amount of power because of a less resisting force behind the sub, not the other way around
Sorry, but it does not work like that, the port works as a resonator, not as an air leak.
-----------
Maz, there are two factors
- a larger box will result in a higher Q resonator, since there will be less damping on the resonator system. Consequently, the peak will be higher and narrower.
- a larger box will also lower the subwoofers resonance and Qtc, therefore allowing it to move more at lower frequencies. (around the woofers resonance, just like in a sealed box)
One thing that you may be interested to know, is the larger the box (up to a point) the better the cone will be controlled below the ports resonant frequency.
As far as your last question goes, it depends - are you ever going to want to play music with content below 40hz? With the amount of power and the enclosure design, will the required excursion significantly exceed the linear xmax of the subwoofer?
Some subwoofers are actually designed so it is almost impossible to physically bottom out the voice coil/former (instead, you would rip the spider/surround/cone first), but assuming you don't break anything, the only downside is increased distortion.
[ December 27, 2003, 20:07: Message edited by: Bassaholic ]
Sonic Nirvana
Dec 28 2003, 01:24 AM
Personally I'm a believer in sub-sonic filters as you are just wasting power trying to push an un-loaded driver around below tuning frequency and it sounds like crap anyway.....so get rid of it
For someone learning about woofer/enclosure behaviour, I find WINISD Pro is easier to see the "what happens when" scenario then Bass Box, even if Bass Box has certain advantages for more sophisticated modelling.
The "standard" WINISD is quite limited tho'.
Bassaholic
Dec 28 2003, 02:05 AM
As a Bassbox fan, I'd have to say Winisd is getting better - the latest alpha (check winisd forum) has some interesting features...
http://www.linearteam.dk/ [ December 28, 2003, 00:06: Message edited by: Bassaholic ]
GIMPY
Dec 30 2003, 04:18 AM
QUOTE
Originally posted by Critter:
Personally I'm a believer in sub-sonic filters as you are just wasting power trying to push an un-loaded driver around below tuning frequency and it sounds like crap anyway.....so get rid of it
Would you like to go into greater detail about sub-sonic filters, because I am open to different ideas as I am going to be building a box for my sub very soon.
I have no knowledge about sub-sonic filters how they work / what they do etc, other than the filter bit .
So could you elaborate more on them so I can have a better understanding of what they would / could do for me.
Cheers
BlackIce
Dec 30 2003, 12:46 PM
Below tuning frequency in a ported enclosure the sub will act as if in a free-air installation, so the only limits to its excursion is from the suspension. This means the cone can over-excurt, which is bad.
A subsonic filter is basically a high pass filter for subs.. but it passes at a very low frequencies. This limits the power/signal the sub recieves below its tuning frequency, which reduces risk of over excursion.
Generally you'll set it to 5 or 10hz below the tuned frequency of the enclosure. So if you've tuned your subs to 40hz, you'd set the sub-sonic to 30hz, or 35hz.
Quick notes:
- A subsonic filter is part of the amplifier (typically).
- Companies like Alpine do make external ones as part of an external active Xover network.
- Some are adjustable (Eg. JBL BPX 600.1), some aren't but are switchable (Eg. Earthquake D2)
- Typically the subsonics are adjustable between 10hz & 30hz. SPL oriented amps tend to bet adjustable between 10hz & 60hz.
Bassaholic
Dec 30 2003, 08:13 PM
The latest alpha version of winisd pro (check winisd forum) models subsonic filters now.
Slider
Dec 30 2003, 10:12 PM
QUOTE
Originally posted by Bassaholic:
The latest alpha version of winisd pro (check winisd forum) models subsonic filters now.
Yeah downloaded it the other day, might need your help understanding some of the new features. It is alot more comprehensive (sp?) than before.
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please
click here.