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Ascendant Audio Avalanche 18
651 effective liters, 700 raw
13.5hz tuning
Carvin hd1800 amp
This is the old school of thought - today's movies have lots of <20hz bass, and when you have experienced it faithfully reproduced, there is no going back.
To the OP, again, I recommend a large, low tuned SoundSplinter RLp15 - if you can swing it, build two.
SteveCallas said:
I supose this is T/S (Alliance 18):
nom 4 ohms BL 17.24 n/a Cutout diam. 16 3/4
Re 3.8 ohms Sd 1185 cm2 Outer diam. 18 1/2
Fs 14.6 Hz Mms 362 g Mounting depth 8 5/8
Vas 657 L Xmax 20.5 mm Weight 25 pounds
Qms 10.79 Spl 88.7 dB 1W/1M Voice Coil diam. 2.5 inch aluminum
Qes .425 Rms 750W Voice coil Single 4 ohm
Qts .409
OK, close enough. Vb=650 litter, Fb=13,5 Hz (I supose -3 dB at 14-15 Hz). With 600 W (some compression) and its about log(450)=26,5 dB+88,5=115 dB but from 14-100 Hz. For bass-reflex and TL, roll-off is 18 dB/oct. That means about -8 dB at 10 Hz result 107 dB.
It cant be measured anything at that freq. In fact it can, but its irrelevant. Room makes fantastic mess, and there is a question of measure equipment (precission).
You used the parameters of the Alliance 18 - the Avalanche 18 is a different beast (XBL^2 and 27mm excursion). If you check my gallery again, at look at the ported FR at my seat, you'll see I'm pretty darn flat to 10hz with a slight house curve using no EQ. My -3db point is not yet reached at 10hz, it lies somewhere below that - I can only measure to 10hz, so I don't know exactly where it lands.
Now I realize my sub is quite large, and the Avalanche 18 is not your average driver, but it just goes to show infrasonics can be produced at spirited levels without tons of power. The large enclosure and low tune make the sub very efficient down low.
Now I realize my sub is quite large, and the Avalanche 18 is not your average driver, but it just goes to show infrasonics can be produced at spirited levels without tons of power. The large enclosure and low tune make the sub very efficient down low.
SteveCallas said:
But excursion is so long at 10 Hz, you cant know how much is with signal at 10 Hz, and 600 W of power. And how much is SPL with 600 W at 10 Hz and Xmax what is posible. Not what you simulated.
Big box and low tuning makes very long excursion.
Some old tread got calculation for SPL-Xmax:
""p=Sd*Xmax*f^2*pi*rho0/(r*sqrt(2))
where p=sound pressure in Pa, Sd=eqv. piston area in m2, Xmax=max peak excursion in m, f=frequency in Hz, rho0=1.2kg/m3, r=speaker-to-mic distance in m.
The sound pressure p can be converted to sound pressure level
Lp=20*log10(p/0,00002)
So with
Sd=500 cm2
Xmax=10 mm
f=30Hz
r=1
p=0.05*0.01*30^2*3.14*1.2/(1*1.41)=1.2 Pa
Lp = 20*log10(1.2/0.00002)=95.56 dB
Note: It is not certain that it is the cone amplitude that limits max SPL.""
In BassBox Pro simulation with 600 W, at 10 Hz I got 33 mm excursion (one way) and -10 dB from average SPL. F3 (-3 dB) at 14.8 Hz. Cms is not linear, so probably it is not 33mm but some smaller.
All for Alliance 18. Could not find T/S for Avalanche 18.
Keep in mind room gain is giving me some free output down low as well - sub is in my front left corner of the room.
yes he coudl be getting TONNES of room gain, i mean all but the BIGGEST rooms will have room gain at 10hz, and lots of it, its all a matter of having 6.5+ litres of linear displacement, enough power, and a big ported box.
IIRC there was a guy with a HUGE ported subwoofer, two av15s with enough power to bottom them out. and he could burp 120db at 10hz becuase he wasnt in a huge room and had TONNES of displacement.
i dont mean to come off rude, but notax, you are wrong, it is very possable. Anechoic....its porbably not but in a room its more than possable.
man this thread makes my atlas 15 seem like a toy. useable output at 16hz looks like a joke next to >-3db at 10hz.
even in my room though my sub is capable of visibly flexing my windows at 10hz(my room is 12x10x8 feet roughly). Anyone dont believe me? i have a video.
and my sub is not that extreme a design, infact its fairly common, an atlas 15 getting 240 watts in 6.5cu ft tuned to 20hz via two 4" ports. and im getting ALOT of room gain to achieve this.
IIRC there was a guy with a HUGE ported subwoofer, two av15s with enough power to bottom them out. and he could burp 120db at 10hz becuase he wasnt in a huge room and had TONNES of displacement.
i dont mean to come off rude, but notax, you are wrong, it is very possable. Anechoic....its porbably not but in a room its more than possable.
man this thread makes my atlas 15 seem like a toy. useable output at 16hz looks like a joke next to >-3db at 10hz.
even in my room though my sub is capable of visibly flexing my windows at 10hz(my room is 12x10x8 feet roughly). Anyone dont believe me? i have a video.
and my sub is not that extreme a design, infact its fairly common, an atlas 15 getting 240 watts in 6.5cu ft tuned to 20hz via two 4" ports. and im getting ALOT of room gain to achieve this.
For Notax :
Ascendant Audio Avalance 18 driver T/S :
Qts=0,4
Znom=4 ohms
Fs=16 Hz
Pe=800 W
SPL=89.3 dB/1W/1m
Re=3.2 ohms
Le=2.4 mH
BL=16.64 N/A
Xmax=27 mm
Cms=0,268 mm/N
Qms=6
Qes=0,43
Rms=6,18 Ns/m
Mms=369 g
Sd=1210 cm^3
Vas=556.9 liters
USPL=93,3 dB/2.83V/1m
Ascendant Audio Avalance 18 driver T/S :
Qts=0,4
Znom=4 ohms
Fs=16 Hz
Pe=800 W
SPL=89.3 dB/1W/1m
Re=3.2 ohms
Le=2.4 mH
BL=16.64 N/A
Xmax=27 mm
Cms=0,268 mm/N
Qms=6
Qes=0,43
Rms=6,18 Ns/m
Mms=369 g
Sd=1210 cm^3
Vas=556.9 liters
USPL=93,3 dB/2.83V/1m
simon5 said:
Tanks!
Its similar. Vb=525 litter. Fb=16.4 Hz. I got 38-39 mm excursion at 10 Hz with 600 W. Max SPL 117 dB wich roll-off from 20-21 Hz to 97 dB at 10 Hz.
When you measure you got respons od subwoofer (bass unit + port) + respons of the room. Standing waves that goes around 1/2 hour after the signal is finished. 😀
notax, form what youre saying i dont believe you understand room gain. Measure the longest linear dimesion of your room, and find out what frequency it corresponds to. this is where room gain starts. It startes because a full wave can no longer fit into the room and instead of actual waves creating the sound you just have a uniform pressurisation/depressuresation of the room. There CANT be a standing wave, the wave wont even fit into the room.
Now in a perfectly sealed and non absorbant room, room gain is calculated as 12db/octave gain from the longest wave that fits in the room. Although in the average room, usually thats more like 6db/octave gain. Even in rooms with doors/windows open however you still experience this "pressure vessel gain", theres just not as much.
Remeber there are two types of room gain, bondary gain (1/4 space, 1/8 space etc.) and pressure vessel gain.
The link escapes me right now, but adire did a very throrough paper on calculating room gain and how it works.
with this knowledge you can see that in the right room getting huge SPL at low frequencies is not that hard.( but i never said ti was easy!)
Now in a perfectly sealed and non absorbant room, room gain is calculated as 12db/octave gain from the longest wave that fits in the room. Although in the average room, usually thats more like 6db/octave gain. Even in rooms with doors/windows open however you still experience this "pressure vessel gain", theres just not as much.
Remeber there are two types of room gain, bondary gain (1/4 space, 1/8 space etc.) and pressure vessel gain.
The link escapes me right now, but adire did a very throrough paper on calculating room gain and how it works.
with this knowledge you can see that in the right room getting huge SPL at low frequencies is not that hard.( but i never said ti was easy!)
xstephanx said:
I wrote it fast, and one after another, so it seems as I mix standing waves and room gain. I know diference.
I hope you will find that links. It is allways welcome.
1 Hz Sub Woofer?
Hello,
I am new to this topic and do not want to waist anyones time.
Simon5 at post 11 said there is a 1 Hz "fan" driver. Where are the cryogenics in this industry?
Where are the ratios showing magnet temp relative to cone size.
This may seem simple minded, yet air conditioned heat exchangers are more efficient than "fans".
In CRC Handbook Of Physics And Chemistry, there are many magnetic materials that can be highly cooled, before they are super-cooled cryogenic.
Were is the dicscussion for heat removal at the 1 Hz + magnet for subwoofers?
Mark
Hello,
I am new to this topic and do not want to waist anyones time.
Simon5 at post 11 said there is a 1 Hz "fan" driver. Where are the cryogenics in this industry?
Where are the ratios showing magnet temp relative to cone size.
This may seem simple minded, yet air conditioned heat exchangers are more efficient than "fans".
In CRC Handbook Of Physics And Chemistry, there are many magnetic materials that can be highly cooled, before they are super-cooled cryogenic.
Were is the dicscussion for heat removal at the 1 Hz + magnet for subwoofers?
Mark
after the shock wore off, a great effort to not laugh-
note the bandwith, and lowest fz in spec-
http://support.radioshack.com/support_tutorials/audio_video/afq-4001277.htm
was at radio shack, all along...
note the bandwith, and lowest fz in spec-
http://support.radioshack.com/support_tutorials/audio_video/afq-4001277.htm
was at radio shack, all along...
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