like a lot of novices I’m trying to correlate ts parameters into more “subjective” information.
I’m working on a build with these fixed parameters.
2- 12 or 15” woofer per box
250 L net volume, (could be made smaller, thinking add sand bags in less volume is helpful)
Crossover at 4-500hz to 2” compression driver,(BMS 4592)
DSP controlled, 350w @8 Ohm bass amp
Only 2 ch music, no movies, not too concerned about anything under 30-35hz.
For reasons of having DSP eq, large box volume and wanting a very articulate, “fast, tight” bass, I’m planing on sealed boxes.
Articulate and clear are the best words for what I’m looking for in this, say 30-500hz range.
The takeaways I’ve gained from reading is that box size maze a big difference, Dsp can negate “some” t/a parameters.
I’ve been looking at JBL 2216nd, Acoustic Elegance td15s, Faital 15FH520, Faital PR400. BMS 15 woofers, (5 mo wait)
Any advice on how to make a decision based on my parameters? Not necessarily a recommendation m, but a way to better evaluate choices?
Thanks for any perspective.
I’m working on a build with these fixed parameters.
2- 12 or 15” woofer per box
250 L net volume, (could be made smaller, thinking add sand bags in less volume is helpful)
Crossover at 4-500hz to 2” compression driver,(BMS 4592)
DSP controlled, 350w @8 Ohm bass amp
Only 2 ch music, no movies, not too concerned about anything under 30-35hz.
For reasons of having DSP eq, large box volume and wanting a very articulate, “fast, tight” bass, I’m planing on sealed boxes.
Articulate and clear are the best words for what I’m looking for in this, say 30-500hz range.
The takeaways I’ve gained from reading is that box size maze a big difference, Dsp can negate “some” t/a parameters.
I’ve been looking at JBL 2216nd, Acoustic Elegance td15s, Faital 15FH520, Faital PR400. BMS 15 woofers, (5 mo wait)
Any advice on how to make a decision based on my parameters? Not necessarily a recommendation m, but a way to better evaluate choices?
Thanks for any perspective.
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Hi, I guess all of the named woofers are quality products by themselves. I would go for the one with the lightest membrane and the strongest magnet, a.k.a the one with the highest B/L product or lowest Qts and calculate a box volume from there. There might be a roll-off in the bass frequencies, but you may correct it first by placing the speakers in a corner and additionally apply some dsp EQ.
If your goal is a sealed box design, you should simulate these woofers to see how they work in a closed box. Most pro-sound woofers are tailored for vented box applications, but there are exceptions.
Yes, if we follow the guideline of higher qts for sealed boxes, there are not many above .4. I’ve read a Joseph Crowe article about using a higher Qts woofer (.5 or so) SB Audience Bianco 350 in a sealed box. Even with the open baffle craze there are not a lot of high Q woofers. That’s why I’m wondering about the whole Q parameter, and it’s importance.
Ok, first things first in no particular order.........
T/S theory explained
We are always trading efficiency for BW
There's 'no replacement for displacement' (Sd*Xmax)
Vented alignment explained
Sealed alignment explained/Qtc slope order chart
The lower the Qts', the higher its roll off frequency (over-damped)
The higher the Qts' the lower its roll off frequency (under-damped)
Qts' dominates vented box design until Vas becomes truly huge: net volume (Vb) (L) = 20*Vas*Qts'^3.3
Qts' dominates sealed box design
Driver Fs dominates both sealed and vented box tuning: (Fb) (Hz) = 0.42*Fs*Qts'^-0.9
T/S theory peters out at the driver's two mass corners:
upper: Fhm = 2*Fs/Qts'
lower: Flc = Fs*Qts'/2 (AFAIK only used for reactance annulled BLHs)
Qts': 2*Fs/Fhm
(Qts'): (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html
Basic Car Audio electronics
There's more, just ran out of time/memory 🙁, so the rest of you feel free to add to it..........
Thank you for the info and links. I will read, or reread, the info and ponder some more.
It seems like so much talk with woofers is ONLY how low they go and what is the roll off profile? I’m equally concerned with, “ How does it SOUND at 100-500hz?” Subjective I know, but wondering what insight the specs can give to sound qualities of the upper 1/2 of the woofers range.
I know, there are no easy and certain answers, and I’ll never really know until installed and listening in my room.