Cars Resonant Frequency.

[hawkei67]

I went by all the suggestions given and applied them to the design I want with the single Polk Audio db104 10" 300 watt sub in a single tuned bandpass box and 60Hz comes down to about 0dB and the highest gain is 10.6dB which starts at 43.29Hz and stays that way down to 42.17dB with a slight dip of 6.13dB at 20.27Hz and stays at that dB level down to 17.33Hz and then very gradually starts climbing back up in dB the lower you go with the frequency from there, all that info was from the Normalized Amplitude Response graph. On the Custom Amplitude Response graph I get 108.7dB at around 60Hz and climbs up dramatically on the lower end of the frequency band to a maximum of 119.6dB at 42.73Hz and has a slight dip around 22.21Hz with 115.1dB and stays at that dB level down to 14.24Hz then it slowly starts climbing back up in db the lower you get on the frequency band. I have it designed with 2 2.75" round ports flush on both ends and a length of 3.604". The lower frequency chamber of the bandpass is tuned at an Fb of 34.32Hz with an F3 being 5Hz. The high frequency chamber of the bandpass is tuned at an Fb of 43.4Hz with an F3 of 54.63Hz. The Cone Displacement goes up to about 8.69 mm at 31.63Hz (the subs maximum xmax level is 8.71 mm) with a lowest point dip of 3.27 mm at 43.29Hz. The Vent Air Velocity never goes any higher than 29.6 m/s at 43.29Hz. Here is the information for anyone to check out and verify if this is a better box than the current 2 8" csw-800's I have in a sealed box. I use BassBox Pro 6.22. External dimensions are: 14"H (A and E) X 30"W (C and D) X 25.82"D ( B ). The volume for the lower frequency chamber is 2.43 cu. ft. total and the volume of the high frequency chamber is also 2.43 cu. ft. total. Is this a feasible design now that I applied you guys/gals suggestions? Please let me know if I should go with this one or just keep the 2 old school radio shack csw-800's 8" subs in the sealed box. Is this the highest gain I can expect from this single sub? Do you think I can get more out of it than 119.6dB?

Driver Properties

Name: db10 (4 ohm)

Type: Standard one-way driver

Company: Polk Audio

Comment: DB Series

No. of Drivers = 1

Fs = 26.7 Hz

Qms = 4.91

Vas = 44.9 liters

Cms = 0.24 mm/N

Mms = 148 g

Rms = 5.058 kg/s

Xmax = 8.7 mm

Xmech = 25.4 mm

P-Dia = 215 mm

Sd = 363 sq.cm

P-Vd = 0.316 liters

Qes = 0.409

Re = 3.7 ohms

Z = 4 ohms

BL = 15 Tm

Pe = 300 watts

Qts = 0.376

no = 0.201 %

1-W SPL = 85 dB

2.83-V SPL = 88.54 dB

-----------------------------------------

Box Properties

Name:

Type: Bandpass Single-Tuned Box

Shape: Prism, Bandpass

with two chambers

Chamber 1 - lower-freq.

Vb = 2.374 cu.ft

Fb = 34.32 Hz

QL = 6.889

F3 = 5 Hz

Fill = none

Chamber 2 - upper-freq.

Vb = 2.483 cu.ft

Fb = 43.4 Hz

QL = 7

F3 = 54.63 Hz

Fill = none

No. of Vents = 2

Vent shape = round

Vent ends = two flush

Dv = 2.75 in

Lv = 3.604 in

[hawkei67]

Or would this single tuned bandpass (q-logic 110.2 design) which has a higher peak Normalized Amplitude Response of 11dB at 49.99Hz with the 0dB point ending around 69Hz and drops to 5.38dB at 25.99Hz on the lower frequency end and then starts climbing back up reaching a max of 6.60dB on the lowest frequency which is 5Hz. The Custom Amplitude Response looks better too with it maxing out at 120dB at 49.99Hz and the 109dB point ends at around 69Hz, and on the lower frequency end it dips down sharply to 114.3dB at 27.03Hz and stays at that level down to 25.32Hz and very gradually starts climbing back up to a maximum of 115.6dB at 5Hz. The Cone Displacement looks ok, not as good as the other one but acceptable I guess, it reaches 8.70 mm (xmax of sub is 8.71 mm) at 32.46Hz and has the lowest dip at 49.99Hz of 2.96 mm. The Vent Air Velocity is still in the safe range maxing out around 30.7Hz at 30.7 m/s. So should I go with this one instead? Is this the highest possible gain I can expect from this sub for the type of music I listen to and the type of car it will be in? I promise I want bother you guys/gals much longer, I just wanna make sure everything looks correct to some pro's before spending the money for the MDF material, kinda tight on money but I do have wood glue, nails, nail gun, caulk, shingle tar, all the necessary stuff except the cutouts for the box on MDF. Like the old saying goes "Measure twice and cut once". Please bare with me till I get this box perfected for this particular car, amp and sub setup.

File: qlogic QL-110.2 bandpass.bb6

-----------------------------------------

Driver Properties

Name: db10 (4 ohm)

Type: Standard one-way driver

Company: Polk Audio

Comment: DB Series

No. of Drivers = 1

Fs = 26.7 Hz

Qms = 4.91

Vas = 44.9 liters

Cms = 0.24 mm/N

Mms = 148 g

Rms = 5.058 kg/s

Xmax = 8.7 mm

Xmech = 25.4 mm

P-Dia = 215 mm

Sd = 363 sq.cm

P-Vd = 0.316 liters

Qes = 0.409

Re = 3.7 ohms

Z = 4 ohms

BL = 15 Tm

Pe = 300 watts

Qts = 0.376

no = 0.201 %

1-W SPL = 85 dB

2.83-V SPL = 88.54 dB

-----------------------------------------

Box Properties

Name:

Type: Bandpass Single-Tuned Box

Shape: Prism, Bandpass

with two chambers

Chamber 1 - lower-freq.

Vb = 2.551 cu.ft

Fb = 33.95 Hz

QL = 7

F3 = 5 Hz

Fill = none

Chamber 2 - upper-freq.

Vb = 2.401 cu.ft

Fb = 49.86 Hz

QL = 7

F3 = 63.24 Hz

Fill = none

No. of Vents = 2

Vent shape = round

Vent ends = two flush

Dv = 2.75 in

Lv = 2 in

[hawkei67]

And by the way: Those results are with the old pioneer 220 watt amp wide open. Forgot to mention that.

[hawkei67]

And by the way: Those results are with an input power of 220 watts because I will be using the old Pioneer 220 watt amplifier. Forgot to mention that.

[Ray]

Horrible box design.

Wayyyyyyyyy to big, tuning freq's are off and the f3's are plain retarded.

Maybe pay for a design, or just do a reg 1.5cuft ported box.

You dont quite gey bp design yet

[hawkei67]

I took your suggestion and designed a simple ported one around my sub Fs in a 14"H X 18.34"W X 14"D (prism/square) with 1.523 cu.ft. of total volume and 1 single round vent at 2.75" diameter and 13" long and flush on both ends. The 0dB point starts at 90.06Hz on the high frequency end and rises to a steep tip of 8.05dB around 27.03Hz and then drops down to the 0dB point around 14.50Hz on the low frequency end on the Normalized Amplitude Response graph. The Custom Amplitude Response graph shows 117dB max with the 109dB points being at 90.06 for the HF end and around 14.50Hz for the LF end. The Cone Displacement is still under a safe level of 8.29mm at 22.21Hz with the dip being lowest at 27.03Hz of 2.90mm. The Vent Air Velocity looks safe too peaking to 33.6 m/s at 24.03Hz. Those results were with an input power of 220 watts. Does this one sound like a pretty descent design and worth the money for the cutouts? Thank you for the polite response and help. It is greatly appreciated. Here is the vented 1.5cu.ft. design if you would look at it and let me know if I did this one right and it will be worth the trouble of putting together.

Driver Properties

Name: db10 (4 ohm)

Type: Standard one-way driver

Company: Polk Audio

Comment: DB Series

No. of Drivers = 1

Fs = 26.7 Hz

Qms = 4.91

Vas = 44.9 liters

Cms = 0.24 mm/N

Mms = 148 g

Rms = 5.058 kg/s

Xmax = 8.7 mm

Xmech = 25.4 mm

P-Dia = 215 mm

Sd = 363 sq.cm

P-Vd = 0.316 liters

Qes = 0.409

Re = 3.7 ohms

Z = 4 ohms

BL = 15 Tm

Pe = 300 watts

Qts = 0.376

no = 0.201 %

1-W SPL = 85 dB

2.83-V SPL = 88.54 dB

-----------------------------------------

Box Properties

Name:

Type: Vented Box

Shape: Prism, square

Vb = 1.498 cu.ft

Fb = 26.72 Hz

F3 = 12.07 Hz

Fill = none

No. of Vents = 1

Vent shape = round

Vent ends = two flush

Dv = 2.75 in

Lv = 13 in

[Ray]

Use a 4" and tune to 32

[hawkei67]

How about this one with a single 4" diameter round vent at 12.5" long flush on both ends, the box is tuned to 34.06Hz in a 1.854 total cu. ft. box of 14"H X 22"W X 14"D (Prism/Square) using .75" MDF. The highest gain is 9.12dB at 35.58Hz and the 0dB points end up at 256.5Hz on the HF end and 20.81Hz on the LF end on the Normalized Amplitude Response. The Custom Amplitude Response shows a max dB of 118.1dB at 35.58Hz. The Cone Displacement is at a safe point of 8.52mm at 27.03Hz and the dip is at 34.21Hz at 3.10mm. The vent air velocity is at a very safe maximum level of 20.4 m/s at 33.76Hz. Here is the information for all to check out and let me know if I did it right and if it will be a hard hitting box in my car running 220 watts maximum through it. Should I go with this? Does it seem like it will hit harder, lower, louder and sound better overall than the 2 cheapo Radio Shack 8" CSW-800's in the sealed box that is already in the car?

Driver Properties

Name: db10 (4 ohm)

Type: Standard one-way driver

Company: Polk Audio

Comment: DB Series

No. of Drivers = 1

Fs = 26.7 Hz

Qms = 4.91

Vas = 44.9 liters

Cms = 0.24 mm/N

Mms = 148 g

Rms = 5.058 kg/s

Xmax = 8.7 mm

Xmech = 25.4 mm

P-Dia = 215 mm

Sd = 363 sq.cm

P-Vd = 0.316 liters

Qes = 0.409

Re = 3.7 ohms

Z = 4 ohms

BL = 15 Tm

Pe = 300 watts

Qts = 0.376

no = 0.201 %

1-W SPL = 85 dB

2.83-V SPL = 88.54 dB

-----------------------------------------

Box Properties

Name:

Type: Vented Box

Shape: Prism, square

Vb = 1.841 cu.ft

Fb = 34.06 Hz

F3 = 17.19 Hz

Fill = none

No. of Vents = 1

Vent shape = round

Vent ends = two flush

Dv = 4 in

Lv = 12.5 in

[hawkei67]

Or this one. This one does seem a better one than the others but I would like to hear you guys/gals opinion.

Driver Properties

Name: db10 (4 ohm)

Type: Standard one-way driver

Company: Polk Audio

Comment: DB Series

No. of Drivers = 1

Fs = 26.7 Hz

Qms = 4.91

Vas = 44.9 liters

Cms = 0.24 mm/N

Mms = 148 g

Rms = 5.058 kg/s

Xmax = 8.7 mm

Xmech = 25.4 mm

P-Dia = 215 mm

Sd = 363 sq.cm

P-Vd = 0.316 liters

Qes = 0.409

Re = 3.7 ohms

Z = 4 ohms

BL = 15 Tm

Pe = 300 watts

Qts = 0.376

no = 0.201 %

1-W SPL = 85 dB

2.83-V SPL = 88.54 dB

-----------------------------------------

Box Properties

Name:

Type: Vented Box

Shape: Prism, square

Vb = 1.841 cu.ft

Fb = 32 Hz

F3 = 15.67 Hz

Fill = none

No. of Vents = 1

Vent shape = round

Vent ends = two flush

Dv = 4 in

Lv = 14.78 in

[hawkei67]

I may be misunderstanding all of it, I just want a harder hitting (vibrating) but sounds good on the standard low ends using that 10" or the 2 old 8" using the same 220 watt amp I have listening to the type music I mentioned in my first post. What do you guys suggest, I would like it to be in a prism/square or cube shape without going over my max trunk specs of 14" high x 38" wide (side to side) x anywhere between 9" deep to 30" deep and would like the ports facing upward (without retardation from the bottom of my rear deck where my 5x7's are) or forward (toward the drivers section) with the speaker on one of the sides or facing the rear of the trunk without any wedge or angles, just a simple box. I would like to accomplish this using the current software which is BassBox Pro 6.20-22 (I enjoy using it as a learning tool), and I have tried TermLab, WinIsd, the one programmed and posted by a user on this site, but yet I enjoy using what I have. I just need some guidance as to understanding and interpreting the final results and how to maximize them to their fullest potential without any damage to the sub/amp/ect... and achieve a design to build from that prediction of results so when people listen to it then they won't believe it when they see how small, but yet strong and clear the bass of that thang is, it is a sense of accomplishment project so to speak, you know, being able to proudly tell your peers "I built it" and then they will want me to design one just for their particular car and setup, you get the picture. Anyway, thank you to all of you who responded with an open mind without disrespect. Keep up the great work Mods!