I am currently working on a custom ABC enclosure that will be designed for SQ while maximizing spl. I would like to know how I can figure out the optimal size for my enclosure in order for the woofer to reach x-max, at 1000 watts. The enclosure will be tuned to roughly 27hz. perhaps a bit lower
JL 12w7
specs as follows:
Free Air Resonance (Fs) 27.2 Hz
Electrical “Q” (Qes) 0.514
Mechanical “Q” (Qms) 7.807
Total Speaker “Q” (Qts) 0.482
Equivalent Compliance (Vas) 2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax)* 1.15 in / 29 mm
Reference Efficiency (no) 0.249%
Efficiency (1 W / 1 m)** 86.2 dB SPL
Effective Piston Area (Sd) 84 sq in / 0.0542 sq m
DC Resistance (Re) 2.47 Ω
JL 12w7
specs as follows:
Free Air Resonance (Fs) 27.2 Hz
Electrical “Q” (Qes) 0.514
Mechanical “Q” (Qms) 7.807
Total Speaker “Q” (Qts) 0.482
Equivalent Compliance (Vas) 2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax)* 1.15 in / 29 mm
Reference Efficiency (no) 0.249%
Efficiency (1 W / 1 m)** 86.2 dB SPL
Effective Piston Area (Sd) 84 sq in / 0.0542 sq m
DC Resistance (Re) 2.47 Ω
I modeled it in Akabak. As I recall, I didn't like the resulting frequency response----huge dip within the passband.
EDIT: yup found it...
EDIT: yup found it...
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I'm not sure I understand the graph. I just want to design an enclosure that will maximize the Xmax of the driver. (30mm) it won't play below 25 hertz often and my amp has an lpf set at 30. 24db/octave
Don't want to sidetrack content.
That's presuming it's a BR, a sealed type looks also great?! A sealed 100L looks good for home environment with a Qtc = 0.65 (sealed good from 65-200L).
Note: the Sealed Enclosure Specifications is good maybe only for car with only Volume (net int.) 1.375 cu ft / 38.94 L
Following your line of though, with easy build enclosures not mentioning horns/others, I looked at a good alignment from VB = 100.0 L, FB = 22 Hz what would be good maybe in open space/freefield with very low F3~19/21Hz (in room/freefield).
Again , jlaudio shows for ported Volume (net int.) 1.75 cu ft / 49.6 L, what might work in car not home (65-150L)
You need to have in mind that this is a subwoofer and you have to much of infra sound. A smaller box VB = 80.0 L, FB = 20Hz might work. 27Hz tunning (look below) makes a bigger lob @40Hz that might compensate rolloff, I don't know, without further measuring or simulating. Maybe you are using active equalization or other means of control that I'm not used to/or don't use. Please criticize this.
deebeez92, what (calculations/simulation) base do you have to say that. So I can follow you up...
That's presuming it's a BR, a sealed type looks also great?! A sealed 100L looks good for home environment with a Qtc = 0.65 (sealed good from 65-200L).
Note: the Sealed Enclosure Specifications is good maybe only for car with only Volume (net int.) 1.375 cu ft / 38.94 L
Following your line of though, with easy build enclosures not mentioning horns/others, I looked at a good alignment from VB = 100.0 L, FB = 22 Hz what would be good maybe in open space/freefield with very low F3~19/21Hz (in room/freefield).
Again , jlaudio shows for ported Volume (net int.) 1.75 cu ft / 49.6 L, what might work in car not home (65-150L)
You need to have in mind that this is a subwoofer and you have to much of infra sound. A smaller box VB = 80.0 L, FB = 20Hz might work. 27Hz tunning (look below) makes a bigger lob @40Hz that might compensate rolloff, I don't know, without further measuring or simulating. Maybe you are using active equalization or other means of control that I'm not used to/or don't use. Please criticize this.
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Okay example. My current setup is 1.67 cu ft ported at 31 Hz. At roughly 900 watts, the woofer is no where near x max. I'm trying to design an ABC enclosure, and I just want to know how I figure out what size I need for me to optimize the drivers long throw.
I've read the ABC's have a much larger tuning shelf so i'd like to tune lower, (ex 27 Hz, maybe even lower) but then i'll begin to lose out around the upper 50's. The sub wont be playing much above 65 and won't play anything below 20 - infrasonic filter 24 db's / octave.
sealed is definitely out of the question.
note, i'm also aiming for a Qtc of 0.5 - 0.6
I've read the ABC's have a much larger tuning shelf so i'd like to tune lower, (ex 27 Hz, maybe even lower) but then i'll begin to lose out around the upper 50's. The sub wont be playing much above 65 and won't play anything below 20 - infrasonic filter 24 db's / octave.
sealed is definitely out of the question.
note, i'm also aiming for a Qtc of 0.5 - 0.6
quick question regarding Xmax. in win isd does the cone excursion refer to one way come travel or two way. and should I be thinking of come excursion as both halves or simply as the one way linear motion (Xmax or rear Xmax plus front Xmax) peak to peak
Xmax is one way travel and given a symmetrical magnetic field should be equal for the forward and the reverse movement.
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