ported vs sealed which do you preffer?

[busy road]

yung tungkol sa enclosure (box) may recommended naman ang maker nung sub, usually kasama sa manual, na design at dimensions. mas maganda sundin na lang recommendations ng manufacturer.

Bro, you're right. Though dimensions are not given, volume and tuning frequency are enough. I saw one ...http://www.rockfordfosgate.com/produ...9&locale=en_US

[tracer1]

Bro, mas maganda kasi kung actual ang testing. In any case try to figure out nalang.

To design your Bass Speaker Enclosure, the main target is to determine the box volume and at what optimum resonance frequency it can deliver. The resonance frequency (Hz) is the effective bass that the box can produce. Without the speaker parameters and some calculations it will be hard to achieve the correct box volume.

One of my Simple Projects: (Mid range and tweeter speakers are excluded)

Speaker Type: PRO-W88AD
Maximum and Nominal Power: 150/100 Watts
Impedance: 8 Ohms
Manufacturer: DAI-ICHI

First, you have to determine the parameters:
1) Fs = free-air resonance frequency
2) Qts = total magnification factor
3) Vas= equivalent air volume compliance

Free-Air Resonance Frequency:

Set up diagram(see attachment)

First, calibrate by inserting the 10 ohm resistor in place of the driver.
Adjust the voltage output of the audio frequency sine-wave generator until the ac voltmeter reads 0.01 volts.
Replace the 10 ohm resistor with the driver to be tested.
Keep the output voltage constant. 0.01 volts represents 10 ohms, 0.015 volts represents 15 ohms, etc.
Vary the frequency control of the audio frequency generator to find maximum resistance (Rmax). At that point, frequency is resonant frequency (Fs).
With this test I got:
Fs = 53 Hz (*Rmax = 25.7 ohms)

Total Magnification Factor:

Re = 7.4 ohms (measured speaker dc resistance)

Ro = Zmax / Re = 25.7/7.4 = 3.47 ohms

Rx = (ro)^1/2 X Re = (3.47)^1/2 X 7.4 = 13.8 ohms

Impedance to frequency curve(see attachments)

Adjust the sine-wave or frequency generator until the resistance is equal to Rx. This will occur twice as shown in the graph above. F1 is the lower frequency when the resistance equals Rx. F2 is the higher frequency when the resistance equals Rx.
Rx = 13.8 ohms
F1* Rx = 29Hz
F2* Rx = 92Hz

Qms = the mechanical control coming from the suspension system's damping abilities.

Qms = Fs X (ro)^1/2 / (F2-F1) = 53 X (3.47)^1/2 / (92-29) = 1.56778

Qes = the electrical gauge of the control on a driver coming from the counter - EMF generated in the voice coil.

Qes = Qms / (ro-1) = 1.56778 / (3.47-1) = 0.63473

Qts = the total Q of the driver.

Qts = (Qms X Qes) / (Qms + Qes) = (1.56778 X 0.63473) / (1.56778 + 0.63473)
Qts = 0.452

To determine the Vas, it needs test box with volume=0.5154 Ft^3 for 8" speaker or use 1 ft^3 for 12" speaker. Using the above test procedure, determine the FCT or resonance frequency of the speaker while on the test box. In my case, I got 93 Hz.

Vas = 1.15[(FCT/Fs)^2 – 1] X Vbs = 1.15[(93/53)^2 – 1] X 0.5154
Vas = 1.223 ft^3

The speaker Parameters Are:
Fs = 53 Hz.
Qt = 0.452
Vas = 1.223 ft^3

Base on these parameters you can compute the following:

Box Volume:

Vb = 15(Qt)^2.87 X Vas = 15(0.452)^2.87 X 1.23

Vb = 1.889 Ft^3 (This is the volume required to design the enclosure)
Add approximately 10% of the computed volume to compensate the mass volume of the speaker, fiberglass, and any material enclosed.

Box Resonance Frequency:

Fb = (Vas/Vb)^0.32 X Fs = (1.23/1.889)^0.32 X 53

Fb = 46.2 Hz (This is the optimum effective frequency of the box)


So the next move is to determine the size of the port tube and the speaker already fixed. In my case, I used 3” Diameter PVC tube. You can reduce the diameter but be sure it will not create a whistling sound. The length of the tube can be determined from the port table (I wish e-copy is available) or trying different length with the aid of frequency generator. The target resonance frequency is 46.2 hertz at maximum impedance. Try adjusting the length of the port tube until you achieve 46.2 hertz at maximum impedance.

Hope this will help in understanding speaker enclosure. Though, more on theory parin ang dating. Sensiya na bro.
Kung gusto mo talagang mag-design, I suggest the book of David Whims - Speaker Design, which is available in any book store.

OK noted,
kaso hindi rin lahat yan masusunod depende parin sa pag lalagyan,
example: pano kung VOX Beetle, mini cooper (austin) at iba pang small cars pag lalagyan ng subs? lalo na kung gusto ng customer yung boom-boom talaga na bastos sa tunog pero an liit ng space ng oto nya?

kung susundin ang exact ratios indicated para sa capacity ng isang sub sacrifice naman ang space na paglalagyan kasi no choice na mag iba rin ang design ng box o pano kung hindi box? fiberglas molding?

may nasusunod din kayang sukat dun tulad sa mga series ng PIMP my ride na kadalasan molding ng fiberglas sa mga trunks and sidings? pero ok parin ang sound.


Anyway bro thanks sa detailed explanations mo nanariwa tuloy ece days ko

[busy road]

OK noted,
kaso hindi rin lahat yan masusunod depende parin sa pag lalagyan,
example: pano kung VOX Beetle, mini cooper (austin) at iba pang small cars pag lalagyan ng subs? lalo na kung gusto ng customer yung boom-boom talaga na bastos sa tunog pero an liit ng space ng oto nya?

kung susundin ang exact ratios indicated para sa capacity ng isang sub sacrifice naman ang space na paglalagyan kasi no choice na mag iba rin ang design ng box o pano kung hindi box? fiberglas molding?

may nasusunod din kayang sukat dun tulad sa mga series ng PIMP my ride na kadalasan molding ng fiberglas sa mga trunks and sidings? pero ok parin ang sound.


Anyway bro thanks sa detailed explanations mo nanariwa tuloy ece days ko

I think bro natumbok mo ang solution. Di ko naisip na pwede palang magpa-mold ng fiverglass. As long as the volume space is correctly considered in any irregular shape, pwede siya. Ang rule naman kasi ay iwasan ang box na perfect cube. By the way, mas maliit ang volume requirement ng closed than ported box with the same speaker. Kaya for limited space, try closed box nalang. I am pretty sure piece of cake lang sa iyo pag-gamit ng mga test instruments.

[ReccaH]

i heard more power daw ang required to power a sealed than a ported?

[busy road]

i heard more power daw ang required to power a sealed than a ported?

I don't know the experienced of other fellow tsikoters. Generally, if your box or enclosure is correctly designed for optimum frequency response, even small amount of power you will notice the good bass quality your box can deliver.

Try it yourself. Good setup from player-equalizer-amplifier or any additional enhancement, you will hear the good bass response from as little as 5watts or less. There is a misconception between loudness and good bass.

If your bass response is not correct, it needs big power to produce loudness or to magnify the available bass to satisfy the listener, say 95 decibels *100watts. On the otherhand, 95 decibels *50 to 75 watts can also be achived from enclosure with good bass response. Though, I preferred ported, it is advisable to used closed enclosure for space considerations.

[Memphis Raines]

ported vs sealed which do you preffer? ano po ba nag mas maganda?

Tried both na for my car and I stuck to ported. More earthshaking Bass and hindi pa mahirap i-drive. Mas guminhawa ang RF Power 800s ko na amps.

[ReccaH]

So good design lang pala. Thanks busy road.

[sprint]

sir papanu na tu-tune and box? anung ibig sabihin nung 40hz para sa 15"
tsaka 37 hz sa mga 12"?
anung sukat tlaga ng ported box para sa 15" un kc ang gusto ko,
maraming salamat

[busy road]

sir papanu na tu-tune and box? anung ibig sabihin nung 40hz para sa 15"
tsaka 37 hz sa mga 12"?
anung sukat tlaga ng ported box para sa 15" un kc ang gusto ko,
maraming salamat

Kung wala kang test instrument like frequency generator, the easiest way is to use closed or sealed enclosure using the data supplied with the speaker. Open this site as an example under especifications.
http://www.rockfordfosgate.com/products/product_details.
It is mentioned here the required internal volume of the enclosure for that particular speaker (of course yours will not be the same specs). The only problem then is that you can't measure the box resonance frequency if you don't have the necessary test instrument as mentioned earlier in this thread. Though for sure, you will be on the correct side to expect the optimum response of the box. So, without the supplied informations regarding your speaker and some test results, it will be hard for you to determine the volume required. I suggest, buy speakers with supplied information to get rid of calculation and testing.
Regarding your question about 40Hz for 15" and 37Hz for 12", it can be one of your speaker free-air resonance frequency or that may be the box resonance of your enclosure with the spaeker. Check if these are Fs (resonance frequency) or Fb (box resonance).

[sprint]

sir isa pa pong prublema, may ugong, statik ang seps tsaka horn pag 2matakbo ang makina, pag bumusina ka, bumubusina din spes, pro mahina lang, tsinek ko na ang ground ng HU ok, ang power supply ng amp ok, salamat po,

[busy road]

sir isa pa pong prublema, may ugong, statik ang seps tsaka horn pag 2matakbo ang makina, pag bumusina ka, bumubusina din spes, pro mahina lang, tsinek ko na ang ground ng HU ok, ang power supply ng amp ok, salamat po,

If you are using passive crossover on your speakers, then the problem is your driver (player to amps). The external source of unwanted sound is being amplified and reproduce by the speakers.
Try this method: try to put condenser (suppressor) capacitors between + polarity to ground on all electronics components of your setup. If the negative polarity supply wire is long enough between ground and the setup, try to put also condenser capacitor between -polarity and ground. If this method failed, maybe there is something wrong with your filter (electrolytic) capacitors of one of your components. Usually these capacitors are connected between +supply and the ground.
By the way, I didn't asked you if the problem comes only when you are in radio mode.

[sprint]

khit po naka AUX or cd meron tlaga ugong, lalagyan ko pla cap. ung ground naman, hindi ko natry un eh, maraming salamat po,

[busy road]

khit po naka AUX or cd meron tlaga ugong, lalagyan ko pla cap. ung ground naman, hindi ko natry un eh, maraming salamat po,

Very complex ang ganyang problema. Another method to eliminate or minimize the unwanted sound is to use power supply filter called PI comprising of two capacitors and a choke coil connected to +polarity with respect to ground. You can ask any electronics shops. Be sure to consider the ampere rating of the choke coil to minimize the voltage drop.
If the method above still failed, check all you connections specially the audio carrying wires between each section of your setup. Shield them with metallic material and connect it to ground.

[tracer1]

khit po naka AUX or cd meron tlaga ugong, lalagyan ko pla cap. ung ground naman, hindi ko natry un eh, maraming salamat po,

sa mga oto minsan hindi nakaka resolve ng problem ang ordinary electrolytic capacitor kahit 1farad pa ilagay mo., kasi ang static sa alternator parang radio waves, lagpasan yan sa amp mo kahit gaanong kakapal pa shielded wires na ilagay mo try mo nalang tong[SIZE=2] Noise Filter nato maraming brands nyan available sa electronics shops


60amps + mapagpipilian mo sa Deeco woth 150 lang, pinaka mahal na 300.
[/SIZE]

[radifier]

bro where can i buy frequency generator?im bandpass fan and plan to improve my experience in making subwoofer enclosure

[busy road]

bro where can i buy frequency generator?im bandpass fan and plan to improve my experience in making subwoofer enclosure

I think that is available there. I got mine (company supplied) with model: ISO-TECH IGC2230, made in Taiwan. With counter na ito ranging from 1 Hz to 1 Mhz. I don't remember the price, but I guess it is within Php 10T.

[busy road]

khit po naka AUX or cd meron tlaga ugong, lalagyan ko pla cap. ung ground naman, hindi ko natry un eh, maraming salamat po,

I-try mo yung noise filter na recommended ni tracer1. This could be the one that I am telling you as PI filter. At 60amps ok na ang rating niya. Hindi ka makaka-experience ng voltage dip.

[tracer1]

I think that is available there. I got mine (company supplied) with model: ISO-TECH IGC2230, made in Taiwan. With counter na ito ranging from 1 Hz to 1 Mhz. I don't remember the price, but I guess it is within Php 10T.

bro mura nyan a! compared sa oscilloscope 22k bili ko yr 2000 pa yun.

*busyroad
ganito ba itsura ng gamit mo?

[busy road]

bro mura nyan a! compared sa oscilloscope 22k bili ko yr 2000 pa yun.

*busyroad
ganito ba itsura ng gamit mo?

Mas manipis siya kaysa diyan at digital counter siya. One time I'll send you the picture.

[tracer1]

Mas manipis siya kaysa diyan at digital counter siya. One time I'll send you the picture.

tnx bro laking tulong din yang mga gadgets nayan.