Hey,
I'm in the middle of deigning an enclosure for a Audes 75w104-8. The subwoofer would be used in a room. The room itself is about 35 cubic meters and in the shape of a rectangular prism.
Here is what I've come up with so far :
The parameters for the driver are as follows:
10''
8 Ohms
RMS: 130 W
Max: 200 W
Range 30 - 2000 Hz
Sensativity (2,83 V/1 m) 92 dB
Fs 31 Hz
Mms 37,5 g
BL 12,37 Tm
Q ms 2,83
Q es 0,31
Q ts 0,28
V as 100,5 ltr
This driver is also available in the latest BassBox pro 6 database with all the parameters.
Now is the fact that my F3 is higher than the Fb a problem? Are my F3 and Fb too close to each other? Are they too high at the moment for good SQ? I'm looking more for SQ than SPL.
Any assistance would be great. Thanks.
I'm in the middle of deigning an enclosure for a Audes 75w104-8. The subwoofer would be used in a room. The room itself is about 35 cubic meters and in the shape of a rectangular prism.
Here is what I've come up with so far :
An externally hosted image should be here but it was not working when we last tested it.
The parameters for the driver are as follows:
10''
8 Ohms
RMS: 130 W
Max: 200 W
Range 30 - 2000 Hz
Sensativity (2,83 V/1 m) 92 dB
Fs 31 Hz
Mms 37,5 g
BL 12,37 Tm
Q ms 2,83
Q es 0,31
Q ts 0,28
V as 100,5 ltr
This driver is also available in the latest BassBox pro 6 database with all the parameters.
Now is the fact that my F3 is higher than the Fb a problem? Are my F3 and Fb too close to each other? Are they too high at the moment for good SQ? I'm looking more for SQ than SPL.
Any assistance would be great. Thanks.
Hi Shpiley,
You've done a good simulation job, No worries, everything is in order ..Will post a MJK:sim. tomorrow to prove my statement.Have a look at this:
b
Attachments
Well... I wouldn't dare doing that. Although I agree that the tuning might want to be even a little lower - 55 liters is big enough as it is for this 10'' driver. Actually people usually recommend about 45 liters for this driver, however I did not achieve satisfactory response with an enclosure of that size. Hence I went up to 55, but that's probably as high as I'll go. If I remember correctly - a bigger enclosure than this actually tended to increase the F3 again.
Hi Shpiley,
You've done a good simulation job, No worries, everything is in order ..Will post a MJK:sim. tomorrow to prove my statement.Have a look at this:
b
Haha... well thank you
. I'm really trying to model the best box I can. It is my first project.Attachments
36hz box design.
Driver Properties
Name: 75W104-8 (2003)
Type: Standard one-way driver
Company: Audes
No. of Drivers = 1
Fs = 31 Hz
Qms = 2.83
Vas = 100.5 liters
Cms = 0.689 mm/N
Mms = 37.5 g
Rms = 2.633 kg/s
Xmax = 4.5 mm
Xmech = 6.75 mm
P-Dia = 202 mm
Sd = 320.5 sq.cm
P-Vd = 0.144 liters
Qes = 0.31
Re = 6.4 ohms
Le = 0.933 mH
Z = 8 ohms
BL = 12.37 Tm
Pe = 130 watts
Qts = 0.28
no = 0.931 %
1-W SPL = 91.84 dB
2.83-V SPL = 92.81 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 1.141 cu.ft
Fb = 33.21 Hz
QL = 6.983
F3 = 35.84 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = one flush
Dv = 2.75 in
Lv = 10.48 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 35.54 Hz
Qx = 1.93
Driver Properties
Name: 75W104-8 (2003)
Type: Standard one-way driver
Company: Audes
No. of Drivers = 1
Fs = 31 Hz
Qms = 2.83
Vas = 100.5 liters
Cms = 0.689 mm/N
Mms = 37.5 g
Rms = 2.633 kg/s
Xmax = 4.5 mm
Xmech = 6.75 mm
P-Dia = 202 mm
Sd = 320.5 sq.cm
P-Vd = 0.144 liters
Qes = 0.31
Re = 6.4 ohms
Le = 0.933 mH
Z = 8 ohms
BL = 12.37 Tm
Pe = 130 watts
Qts = 0.28
no = 0.931 %
1-W SPL = 91.84 dB
2.83-V SPL = 92.81 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 1.141 cu.ft
Fb = 33.21 Hz
QL = 6.983
F3 = 35.84 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = one flush
Dv = 2.75 in
Lv = 10.48 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 35.54 Hz
Qx = 1.93
Last edited:
Alternate 31hz box design.
Driver Properties
Name: 75W104-8 (2003)
Type: Standard one-way driver
Company: Audes
No. of Drivers = 1
Fs = 31 Hz
Qms = 2.83
Vas = 100.5 liters
Cms = 0.689 mm/N
Mms = 37.5 g
Rms = 2.633 kg/s
Xmax = 4.5 mm
Xmech = 6.75 mm
P-Dia = 202 mm
Sd = 320.5 sq.cm
P-Vd = 0.144 liters
Qes = 0.31
Re = 6.4 ohms
Le = 0.933 mH
Z = 8 ohms
BL = 12.37 Tm
Pe = 130 watts
Qts = 0.28
no = 0.931 %
1-W SPL = 91.84 dB
2.83-V SPL = 92.81 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 1.5 cu.ft
Fb = 31 Hz
QL = 6.983
F3 = 31.2 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = one flush
Dv = 3 in
Lv = 10.74 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 31 Hz
Qx = 2
Driver Properties
Name: 75W104-8 (2003)
Type: Standard one-way driver
Company: Audes
No. of Drivers = 1
Fs = 31 Hz
Qms = 2.83
Vas = 100.5 liters
Cms = 0.689 mm/N
Mms = 37.5 g
Rms = 2.633 kg/s
Xmax = 4.5 mm
Xmech = 6.75 mm
P-Dia = 202 mm
Sd = 320.5 sq.cm
P-Vd = 0.144 liters
Qes = 0.31
Re = 6.4 ohms
Le = 0.933 mH
Z = 8 ohms
BL = 12.37 Tm
Pe = 130 watts
Qts = 0.28
no = 0.931 %
1-W SPL = 91.84 dB
2.83-V SPL = 92.81 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 1.5 cu.ft
Fb = 31 Hz
QL = 6.983
F3 = 31.2 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = one flush
Dv = 3 in
Lv = 10.74 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 31 Hz
Qx = 2
Hi,
For the bass end in general its not best to optimise F-3dB. F-6dB
is a lot better and sometimes even F-10dB for some drivers.
This allows room gain to work properly and low frequency vent
tunings help prevent overloading below the vent tuning frequency.
Ideally you would add a peaking high pass filter at around
30Hz for AV use, probably not needed in a music context.
The red alignment has near the same -3dB, better - 6dB
much better -10dB. It will sound deeper and tighter.
rgds, sreten.
I'd tune 55L to 30Hz, but reckon 40-45L 33Hz is about right.
For the bass end in general its not best to optimise F-3dB. F-6dB
is a lot better and sometimes even F-10dB for some drivers.
This allows room gain to work properly and low frequency vent
tunings help prevent overloading below the vent tuning frequency.
Ideally you would add a peaking high pass filter at around
30Hz for AV use, probably not needed in a music context.
The red alignment has near the same -3dB, better - 6dB
much better -10dB. It will sound deeper and tighter.
rgds, sreten.
I'd tune 55L to 30Hz, but reckon 40-45L 33Hz is about right.
Attachments
Last edited:
"maybea 2.75 in vent might be a little small ? Could it start causing vent noise ?"
The computer calculated the minimum vent size based on the Sd, x-max, and Fb of the design. On the 31hz design I forced a larger vent than what was the minimum required.
As suggested by sreten, you might be able to reduce the Q of the high-pass filter if you have a lot of room gain in the 30hz region.
The computer calculated the minimum vent size based on the Sd, x-max, and Fb of the design. On the 31hz design I forced a larger vent than what was the minimum required.
As suggested by sreten, you might be able to reduce the Q of the high-pass filter if you have a lot of room gain in the 30hz region.
Last edited:
I punched in those same numbers and kept getting an F3 of 60 something Hz. Then I noticed the "Active 12 dB/oct. HP Filter". After adding this the F3 dropped down dramatically to 31 Hz.
How does that work? What exactly is this "Active 12 dB/oct. HP Filter" and how is it doing this? As I understand it - it's just a filter that filters out the very low frequencies to prevent the subwoofer from trying to reproduce frequencies that it cannot anyway and thus prevent potential damage. Why would this change the graph in such a way?
Last edited:
I punched in those same numbers and kept getting an F3 of 60 something Hz. Then I noticed the "Active 12 dB/oct. HP Filter". After adding this the F3 dropped down dramatically to 31 Hz.
How does that work? What exactly is this "Active 12 dB/oct. HP Filter" and how is it doing this? As I understand it - it's just a filter that filters out the very low frequencies to prevent the subwoofer from trying to reproduce frequencies that it cannot anyway and thus prevent potential damage. Why would this change the graph in such a way?
Hi,
Quick interpretation of the BR + suggested filter...Is it a bad idea?
b
Attachments
A 2 cu ft 2nd order sealed box with an F3 of 30hz can only be 0.18% efficient (84.55dB).
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
The design I gave is a 6th order vented box.
Speakers like the B&W 801, Matrix 800, are 6th order vented, JBL B380 and B460, as are many Electro-Voice designs.
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
The design I gave is a 6th order vented box.
Speakers like the B&W 801, Matrix 800, are 6th order vented, JBL B380 and B460, as are many Electro-Voice designs.
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Of course you are..You've been talking of a BR not a BR System to design... I couldn't make the posted numbers into a 6:th order SYSTEM.
Therefore I stayed with a boosted 4:th order and forget about the posted efficiencies as they wouldn't apply to the mentioned numbers as the compliance ratios needed are way off.
I know this driver very well and don't want to push the envelopes in simple BR designs, in whatever order and name-calling designs that have no connection with what this low xmax driver can be driven safely.
b
PS: More to look at...
Attachments
While the optimum Qts for a 6th order system is 0.312, about any reasonable Qts is usable.
It is also 'kosher' to pretend the motor is a little weaker than it really is, up to about 20% or so. The interesting thing about this pretense is the harder you drive it, the closer it becomes to optimum (Thiel alignment #15). Most of the EV 6th order designs have too much motor. Technically anything other than 0.312 is not a B6, but becomes a C6 (like the B6 but with small amounts of ripple).
A filter is just that, a filter ahead of the amplifier. It can be active, or passive. Most subwoofer plate amplifiers have one on board, one need only change two resistors (in most cases) to get the Q and frequency right for a given design. I usually modify the crossover or equalizer in a system that has a high-pass filter. Again, it is usually just two resistors.
It is also 'kosher' to pretend the motor is a little weaker than it really is, up to about 20% or so. The interesting thing about this pretense is the harder you drive it, the closer it becomes to optimum (Thiel alignment #15). Most of the EV 6th order designs have too much motor. Technically anything other than 0.312 is not a B6, but becomes a C6 (like the B6 but with small amounts of ripple).
A filter is just that, a filter ahead of the amplifier. It can be active, or passive. Most subwoofer plate amplifiers have one on board, one need only change two resistors (in most cases) to get the Q and frequency right for a given design. I usually modify the crossover or equalizer in a system that has a high-pass filter. Again, it is usually just two resistors.
FYI:
I think the submitted simulations are more in line with djk:s intentions...
Reminds me on the many designs I've made in the late 70:ties...
BTW. I will not bother with more confusing? BR simulations but maybe a T-TQWT/T-QWP I find should provide with more SQ.
b
I think the submitted simulations are more in line with djk:s intentions...
Reminds me on the many designs I've made in the late 70:ties...
BTW. I will not bother with more confusing? BR simulations but maybe a T-TQWT/T-QWP
I find should provide with more SQ.b
Attachments
Wow you guys are really providing me with a lot of useful information, even tough I can't understand a large portion of it haha. I'd quite thankful.
I think my design might not work that well. The large box might make the driver bottom out too much. I had someone hand build an amp for me and it seems like it doesn't have a subsonic filter. So if I have a large box with a high tuning and a low tone of say 15Hz might pop up (pretty ridiculous I know) - I'd be scared of the driver pop'ing as well.
I think I'll be going with djk's design. The 31 Hz box. Vb = 1.5 cu.ft and the vent 3 x 10.74.
If anyone has any objections or other recommendations I'll gladly listen.
I think my design might not work that well. The large box might make the driver bottom out too much. I had someone hand build an amp for me and it seems like it doesn't have a subsonic filter. So if I have a large box with a high tuning and a low tone of say 15Hz might pop up (pretty ridiculous I know) - I'd be scared of the driver pop'ing as well.
I think I'll be going with djk's design. The 31 Hz box. Vb = 1.5 cu.ft and the vent 3 x 10.74.
If anyone has any objections or other recommendations I'll gladly listen.
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