Hi,
So I have a 12" PA driver with a .38 Qts; Fs: 42 hz and EBP = 110 so BR advised. Vas : 113 L, limited Xmax : 7.5 mm : again in favor to BR load choice
Is there bass alignement that are adived based on the Qts driver number ? The Qts seems too big for a SBB4. Not sure a Bessel is the best if transcient (group delay flat enough) is what matters before low pass (passive) filter tweaking not talking about a Fb at 10 hz below the driver Fs if Bessel BR load is chosen !
Which alignement filter would you choose as a start (before low pass filter tweaking) with such Qts which is at the limit before flat and non flat alignement.
My basic understanding is room gain in most of the rooms doesn't really matter above 80 hz, yet matters belllows. Seems most of the time a smooth anechoic magnitude is good enough for most rooms. Something more close to the sealed 18 db slope. (so with BR slope nearer to 24 dB than higher BR slope)
So following that idea, still with my basic understanding about BR load: bigger sized box and more gentle slope.
I admit such a driver should be used as a uper bass-midrange driver. BUT, in an average listening living room, it is "maybe" large enough despite high Qts 42 hz.
What BR alignement would you use as a start before filter tweaking (group delay flatting) if transcient is favored as well as second order low pass filter ? Qts is increased with 0.5 ohms with a good coil and some length from the amp? SSB4 (more advised with Qts near 0.32) ; Bessel (but very low Fb) ?
BR : -F6 is circa 45 hz ; sealed : circa 78 hz.
BR : -F10 is circa 35 hz ; sealed is circa 45 hz.
Again, room gain seems more important below 80 hz in most average living room. And often we have to focus on the 80 hz to 200 hz for that tigth slam psychoacoustic wanted sound (again my basic understanding; Stereophile measurements, etc)
Which trade off BR alignement would you choose going with a passive filter with such driver datas for a bass driver in a 3 ways, please ? (as a start before group delay flattening with a second order passive filter).
My main concern is to use this 12" PA in a living room as a bass driver with a low pass from 200 to 300 hz and making strong enough the 100 hz to 200 hz area where the snap, tigth feeling is.
As going passive I am of course worried about the high pass slope I shoud use for the midrange above!
Hope it is not too much confusing question.
Edit : better to change the driver or at the opposit going active amp with DSP (but I fear the group delay when playing with IR bass boost with such low 7.5 mm Xmax)
So I have a 12" PA driver with a .38 Qts; Fs: 42 hz and EBP = 110 so BR advised. Vas : 113 L, limited Xmax : 7.5 mm : again in favor to BR load choice
Is there bass alignement that are adived based on the Qts driver number ? The Qts seems too big for a SBB4. Not sure a Bessel is the best if transcient (group delay flat enough) is what matters before low pass (passive) filter tweaking not talking about a Fb at 10 hz below the driver Fs if Bessel BR load is chosen !
Which alignement filter would you choose as a start (before low pass filter tweaking) with such Qts which is at the limit before flat and non flat alignement.
My basic understanding is room gain in most of the rooms doesn't really matter above 80 hz, yet matters belllows. Seems most of the time a smooth anechoic magnitude is good enough for most rooms. Something more close to the sealed 18 db slope. (so with BR slope nearer to 24 dB than higher BR slope)
So following that idea, still with my basic understanding about BR load: bigger sized box and more gentle slope.
I admit such a driver should be used as a uper bass-midrange driver. BUT, in an average listening living room, it is "maybe" large enough despite high Qts 42 hz.
What BR alignement would you use as a start before filter tweaking (group delay flatting) if transcient is favored as well as second order low pass filter ? Qts is increased with 0.5 ohms with a good coil and some length from the amp? SSB4 (more advised with Qts near 0.32) ; Bessel (but very low Fb) ?
BR : -F6 is circa 45 hz ; sealed : circa 78 hz.
BR : -F10 is circa 35 hz ; sealed is circa 45 hz.
Again, room gain seems more important below 80 hz in most average living room. And often we have to focus on the 80 hz to 200 hz for that tigth slam psychoacoustic wanted sound (again my basic understanding; Stereophile measurements, etc)
Which trade off BR alignement would you choose going with a passive filter with such driver datas for a bass driver in a 3 ways, please ? (as a start before group delay flattening with a second order passive filter).
My main concern is to use this 12" PA in a living room as a bass driver with a low pass from 200 to 300 hz and making strong enough the 100 hz to 200 hz area where the snap, tigth feeling is.
As going passive I am of course worried about the high pass slope I shoud use for the midrange above!
Hope it is not too much confusing question.
Edit : better to change the driver or at the opposit going active amp with DSP (but I fear the group delay when playing with IR bass boost with such low 7.5 mm Xmax)
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I eventually can ask a different way : if passive filter in your living room (25 to 40 square meters), what -F6 ; - F10 ; - F15 (?) gave you good sounding result whatever sealed or vented load with your bass driver ? (it's about room gain and group delay tweaking in the low pass filter, no ?)
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I don't think it's that helpful to think in terms of 'alignments'. Just put the TSPs into a good modeller such as Unibox and get the low end curve you want. This driver, with a Qts of .38 & Fs of 42 should get to to 40Hz or the high 30s easily; might require a big box though, how big is too big for you?
I usually use butterworth 4th.
Since qts is darn near .4 (I call that the sweet spot), Vb = Vas, Tune to Fs that will be your F3.
When qts goes above that (say .45) then the f3 and tuning go down, but box size goes up.
Vise versa, if qts does down (say .3), you have a much smaller box but louder per watt, but your f3 really shoots up.
Hmm, f3 of 40hz, 2 x 12" woofers (1 a side), sounds fun to me, but a 12" 2-way modulates way sooner than a 12" 3-way.........
12" 2-way, 40 watts is enough b4 modulation distortion to my ears based on my music.
I use 12" 2-ways right now (and a smaller 6" 2-way, maybe a full range driver also), works well, great punch for cone area out 10' and beyond, but sometimes I yearn for the punch of double 15's, or a subwoofer adding a healthy amount of rumble, but then that bring in a whole other set of hookups/complexity/integration/etc.
Since qts is darn near .4 (I call that the sweet spot), Vb = Vas, Tune to Fs that will be your F3.
When qts goes above that (say .45) then the f3 and tuning go down, but box size goes up.
Vise versa, if qts does down (say .3), you have a much smaller box but louder per watt, but your f3 really shoots up.
Hmm, f3 of 40hz, 2 x 12" woofers (1 a side), sounds fun to me, but a 12" 2-way modulates way sooner than a 12" 3-way.........
12" 2-way, 40 watts is enough b4 modulation distortion to my ears based on my music.
I use 12" 2-ways right now (and a smaller 6" 2-way, maybe a full range driver also), works well, great punch for cone area out 10' and beyond, but sometimes I yearn for the punch of double 15's, or a subwoofer adding a healthy amount of rumble, but then that bring in a whole other set of hookups/complexity/integration/etc.
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Going back many years, reading info. about Theil & Small parameters, I was informed about a basic rule of thumb re. optimum box volume >
For a tuned enclosure - for speakers with the 'magic' Qts of .39 , you could simply use a box volume equal to the drivers Vas.
That would make your ideal enclosure roughly 110 L .
That's what I wonder because of the room gain I can not anticipate or measure. That's why I tried to think in term of -F6 or -F10 in spite of the more usual - F3. I have read somewhere most of time the room gain applies below 80 hz down to the Fb, although it is not linear. I eventually understood the knee at the low end should be avoided and a smooth (but how smooth) response a little as a sealed load could give non boomy bass and better group delay? Which is giving a lot of tunning choice from a -F3 between 50 hz to near 80 hz. -3dB being still "flat" and just the beginning of the magnitude fall (but that damned room gain). Trying to make the 100 hz to 200 hz flat cause it is where the slam and tighness is heared.