I've been using a few online calculators to play around with possible boxes for the drivers I have coming and all the calculators come up with boxes that give a Vb of about twice the Vas.
Is this normal?
Although I've had help in the past with a design or two for other woofers I've never actually got around to building any of them due to poor WAF
These are for my Mancave so size won't be a problem this time around.
Just an idle thought here that perhaps the reputation for deep bass is simply the better F10 you get with sealed boxes and a "Q" of 0.5 or less??
I could never afford the IMF Studio Monitors that in my early years had the best bass I've ever heard Pre-Subwoofers and DSP
Is this normal?
Although I've had help in the past with a design or two for other woofers I've never actually got around to building any of them due to poor WAF
These are for my Mancave so size won't be a problem this time around.
Just an idle thought here that perhaps the reputation for deep bass is simply the better F10 you get with sealed boxes and a "Q" of 0.5 or less??
I could never afford the IMF Studio Monitors that in my early years had the best bass I've ever heard Pre-Subwoofers and DSP
Well, a max flat vented alignment is where Vb = Vas, Fb = Fs, Qts' = ~0.403 based on this formula with Qts' dominating till Vas gets relatively large: 20*Vas*Qts'^3.3
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
Right, sealed goes lower, but misses out on the vented's extra half octave of [mid] bass gain before its steeper roll-off.
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
Right, sealed goes lower, but misses out on the vented's extra half octave of [mid] bass gain before its steeper roll-off.
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Given the subject of your post "A TL question", I assume that you're looking at online calculators for TLs?
Most of the online calculators for TL are pretty much ********. They base their calculations on just driver Sd and Fs, completely ignoring Vas and at Qts (or Qes and Qms).
If any of those online calculators don't at least take the following driver parameters into consideration, then they're ********: Vas, Fs, Qts (or Qes and Qms).
Well I was trying to use "Horn Response" but I was finding it difficult with out access to the Help files; running W10Pro I can't open them. Could you recommend something Brian?
I use Hornresp exclusively these days, and I also have a Windows 10 Pro PC.
Check my website out - it gives some ideas on how to use Hornresp to design TLs.
Check my website out - it gives some ideas on how to use Hornresp to design TLs.
What I am trying to do in Horn Response is put in the results of the "On-Line" calculators and see what happens and I can't figure out how the heck I do that?
A well known set of pages that are sometimes useful.
What I was wanting to do was to set that box design into Horn Response and see what was going to happen if I did use that set of measurements.
I want a new set of Mancave speakers and I do want to use the NOS Kicker when it arrives but I want deeper bass than I can get from a sealed box and I really do want to build a "Transmission Line" box.
I have a folding in my head although not yet set down on paper
What I was wanting to do was to set that box design into Horn Response and see what was going to happen if I did use that set of measurements.
I want a new set of Mancave speakers and I do want to use the NOS Kicker when it arrives but I want deeper bass than I can get from a sealed box and I really do want to build a "Transmission Line" box.
I have a folding in my head although not yet set down on paper
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Yeah, that one is pretty much nonsense too. See how they have illustrated distance b around the bend? That should be three different measurements if the negative expansion rate was really being followed. And the "1/3" low tuned option is pretty much nonsense as well.
I guess this would be as good as or better than many of those sites to get you started. Bear in mind that this is just to START you off - the equations describe an unstuffed TL with constant cross-sectional area, and you'll most likely need to tweak the size, length and expansion rate and stuffign of your build to get better results, particularly as these equations do not take Le into consideration or the useful bandwidth that you're trying to achieve.
Given:
Fs = Driver resonance frequency (Hz
Qts = Driver Q at resonance
Vas = Driver's equivalent air compliance (litres)
Calculate:
Fb = Fs / (2.53 * Qts)
Vb = 20 * Vas * Qts ^ 2.35
L = 8500 / Fb
CSA = Vb * 1000 / L
Where,
Fb = TL resonance frequency (Hz)
Vb = TL net volume (litres)
L = TL path length (cm)
CSA = cross-sectional area along the TL's path (cm^2)
Given:
Fs = Driver resonance frequency (Hz
Qts = Driver Q at resonance
Vas = Driver's equivalent air compliance (litres)
Calculate:
Fb = Fs / (2.53 * Qts)
Vb = 20 * Vas * Qts ^ 2.35
L = 8500 / Fb
CSA = Vb * 1000 / L
Where,
Fb = TL resonance frequency (Hz)
Vb = TL net volume (litres)
L = TL path length (cm)
CSA = cross-sectional area along the TL's path (cm^2)
I just put the figures through given your information and the result is a huge box [ 470 litres] and a low tuning of 21 Hz and that isn't all that far from the low tuning in that attached sketch above.
There is room in the Man Cave for such a large box
There is room in the Man Cave for such a large box
I'm having no luck at all and I'm a slow learner so maybe I'll just make them sealed and use DSP
It's a very steep learning curve and I think I'd rather be outside in the sun now we are allowed out to play again
It's a very steep learning curve and I think I'd rather be outside in the sun now we are allowed out to play again
It's an old [ NOS] Kicker the 12 inch in this link Brian
http://www.kicker.com/app/manuals/subwoofers/es/2005_ES_Sub.pdf
I know they work well in sealed boxes as I have the 15" already but poor WAF
http://www.kicker.com/app/manuals/subwoofers/es/2005_ES_Sub.pdf
I know they work well in sealed boxes as I have the 15" already but poor WAF
Yeah, those specs are going to result in a pretty large TL.
I was able to sim a much smaller (134 L TL) with that driver by aiming for a higher Fb of 30 Hz, tapering the design and allowing a bit of a rolloff at the low end, but 134 L still adds up to a fairly big box for a 12" driver with a 7.5" Xmax. It's going to exceed its excursion capabilities with about 100W of power.
I was able to sim a much smaller (134 L TL) with that driver by aiming for a higher Fb of 30 Hz, tapering the design and allowing a bit of a rolloff at the low end, but 134 L still adds up to a fairly big box for a 12" driver with a 7.5" Xmax. It's going to exceed its excursion capabilities with about 100W of power.
