First topic message reminder :

**copy dari website**

Thiele-Small Parameters :
B Magnetic flux density in gap, in Tesla-meters (TM)

BL The magnetic strength of the motor structure. "Expressed in Tesla meters, this is a measurement of the motor strength of a speaker. Think of this as how good a weightlifter the transducer is. A measured mass is applied to the cone forcing it back while the current required for the motor to force the mass back is measured. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority!"

C Propagation velocity of sound at STP, approx. 342 m/s

Cas Acoustical equivalent of Cms

Cmes The electrical capacitive equivalent of Mms, in farads

Cms The driver's mechanical compliance (reciprocal of stiffness), in m/N

D Effective diameter of driver, in meters

F3 -3 dB cutoff frequency, in Hz

Fb Enclosure resonance (usually for bass reflex systems), in Hz

Fc System resonance (usually for sealed box systems), in Hz

Fs Driver free air resonance, in Hz. This is the point at which driver impedance is maximum. "This parameter is the free-air resonant frequency of a speaker. Simply stated, it is the point at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion. If you've ever seen a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from 'ringing'. With a loudspeaker, the mass of the moving parts, and the stiffness of the suspension (surround and spider) are the key elements that affect the resonant frequency. As a general rule of thumb, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs. This is not always the case though, because other parameters affect the ultimate performance as well."

L Length of wire immersed in magnetic field, in meters

Lces The electrical inductive equivalent of Cms, in henries

Le "This is the voice coil inductance measured in millihenries (mH). The industry standard is to measure inductance at 1,000 Hz. As frequencies get higher there will be a rise in impedance above Re. This is because the voice coil is acting as an inductor. Consequently, the impedance of a speaker is not a fixed resistance, but can be represented as a curve that changes as the input frequency changes. Maximum impedance (Zmax) occurs at Fs. "

Ms The total moving mass of the loudspeaker cone.

Mmd Diaphram mass, in grams

Mms The driver's effective mechanical mass (including air load), in kg. "This parameter is the combination of the weight of the cone assembly plus the ‘driver radiation mass load’. The weight of the cone assembly is easy: it’s just the sum of the weight of the cone assembly components. The driver radiation mass load is the confusing part. In simple terminology, it is the weight of the air (the amount calculated in Vd) that the cone will have to push."

n0 The reference efficiency of the system (eta sub 0) dimensionless, usually expressed as %

p (rho) Density of air at STP 1.18 kg/m^3

Pa Acoustical power

Pe Electrical power

Q The relative damping of a loudspeaker

Q Parameters "Qms, Qes, and Qts are measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (this would destroy the loudspeaker). The suspension must also act like a shock absorber. Qms is a measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs. Qes is a measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is called the 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same.

As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications. However, there are exceptions! The Eminence Kilomax 18 has a Qts of 0.56. This suggests a sealed enclosure, but in reality it works extremely well in a ported enclosure. Please consider all the parameters when selecting loudspeakers. If you are in any doubt, contact your Eminence representative for technical assistance."

Qa The system's Q at Fb, due to absorption losses; dimensionless

Qec The system's Q at resonance (Fc), due to electrical losses; dimensionless

Qes The driver's Q at resonance (Fs), due to electrical losses; dimensionless. "A measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock."

Ql The system's Q at Fb, due to leakage losses; dimensionless

Qmc The system's Q at resonance (Fc), due to mechanical losses; dimensionless

Qms The driver's Q at resonance (Fs), due to mechanical losses; dimensionless. "A measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs."

Qp The system's Q at Fb, due to port losses (turbulence, viscousity, etc.); dimensionless

Qtc The system's Q at resonance (Fc), due to all losses; dimensionless

Qts The driver's Q at resonance (Fs), due to all losses; dimensionless. "The 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same."

R Ripple, in dB

Re "This is the DC resistance of the driver measured with an ohm meter and it is often referred to as the 'DCR'. This measurement will almost always be less than the driver's nominal impedance. Consumers sometimes get concerned the Re is less than the published impedance and fear that amplifiers will be overloaded. Due to the fact that the inductance of a speaker rises with a rise in frequency, it is unlikely that the amplifier will often see the DC resistance as its load."

Ras Acoustical equivalent of Rms

Res The electrical resistive equivalent of Rms, in ohms

Rms "This parameter represents the mechanical resistance of a driver’s suspension losses. It is a measurement of the absorption qualities of the speaker suspension and is stated in N*sec/m."

Revc DC voice coil resistance, in ohms

Rg Amplifier source resistance (includes leads, crossover, etc.), in ohms

Rms The driver's mechanical losses, in kg/s

Sd Effective piston radiating area of driver, in square centimeters. "This is the actual surface area of the cone, normally given in square cm."

SPLo Sound Pressure Level, usually measured at 1 watt, at 1 meter in front of the loudspeaker

Vas/Cms "Equivalent volume of compliance", this is a volume of air whose compliance is the same as a driver's acoustical compliance Cms (q.v.), in cubic meters. "Vas represents the volume of air that when compressed to one cubic meter exerts the same force as the compliance (Cms) of the suspension in a particular speaker. Vas is one of the trickiest parameters to measure because air pressure changes relative to humidity and temperature — a precisely controlled lab environment is essential. Cms is measured in meters per Newton. Cms is the force exerted by the mechanical suspension of the speaker. It is simply a measurement of its stiffness. Considering stiffness (Cms), in conjunction with the Q parameters gives rise to the kind of subjective decisions made by car manufacturers when tuning cars between comfort to carry the president and precision to go racing. Think of the peaks and valleys of audio signals like a road surface then consider that the ideal speaker suspension is like car suspension that can traverse the rockiest terrain with race-car precision and sensitivity at the speed of a fighter plane. It’s quite a challenge because focusing on any one discipline tends to have a detrimental effect on the others. "

Vd Maximum linear volume of displacement of the driver (product of Sd times Xmax), in cubic meters. "This parameter is the Peak Diaphragm Displacement Volume — in other words the volume of air the cone will move. It is calculated by multipying Xmax (Voice Coil Overhang of the driver) by Sd (Surface area of the cone). Vd is noted in cc. The highest Vd figure is desirable for a sub-bass transducer."

Xmax/Xmech Maximum peak linear excursion of driver, in meters. "Short for Maximum Linear Excursion. Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap. Although suspensions can create non-linearity in output, the point at which the number of turns in the gap (see BL) begins to decrease is when distortion starts to increase. Eminence has historically been very conservative with this measurement and indicated only the voice coil overhang (Xmax: Voice coil height minus top plate thickness, divided by 2). Xmech is expressed by Eminence as the lowest of four potential failure condition measurements times 2: Spider crashing on top plate; Voice coil bottoming on back plate; Voice coil coming out of gap above core; Physical limitation of cone. Take the lowest of these measurements then multiply it by two. This gives a distance that describes the maximum mechanical movement of the cone."

Zmax "This parameter represents the speaker’s impedance at resonance."

hustle wrote:

sma mcm km gak bro.. seting dlm gelap ngan lmpu suluh.. kekadng pki h/p ja...

alala..pkai hp ja ka?nie msti d jln bru nie..hikhik.

bnyk o sy x phm psl topic yg bru d bka nie..hihi..bkn lg bnyk,hmpr smua lh..klu teori2 nie aku x brapa pndai plak.mau org ajr bru lh aku dpt tngkap..

hustle wrote:

kebykan keta yg aktif roadshow skrg pki tweter karaoke ni... ngam tuk road show la...

pkai horn tweeter ameron..d jamin kpuasannya..

hustle wrote:

kebykan keta yg aktif roadshow skrg pki tweter karaoke ni... ngam tuk road show la...

kalau ikut kan logik, bila main road show ni kan.. target dia main sekuat dan sebising yang boleh. Jadi kalau start pakai tweeter karaoke yang khas untuk di pakai di rumah ni, kali dia ni lebih kuat dari horn tweeter untuk kereta.

jadi ko try pakai PA system punya horn tweeter hehehe

jgn lh bha pula smpai pkai PA system..pkai horn tweeter karaoke nie utk save bajet bha nie..

biasa nya bila kita tengok T-S parameter ni, ada yg boleh menunjuk kan sub-woofer idaman tu ngam ka tidak. Walaupun bukan 100% tepat (sebab performance sub-woofer ni ada lah combination of T-S paramaters & bukan 1 or 2 sahaja), tapi boleh agak2 sub-woofer ni ngam ka tidak.

aduhh napa tidak semua keluar apa yg di taip ni..

contoh dia :

Fs - ni adalah resonance subwoofer tu masa open i.e. teda kotak. Lagi tinggi Fs dia ni (in Hz), ni menunjuk kan subwoofer tu tidak sesuai untuk main bass lembut. Kalau mau main bass lembut, ok cari subwoofer yg Fs nya rendah eg. di bawah 30hz.

Xmax - ni ada lah maximum cone subwoofer tu boleh maju ke depan / belakang. Ukuran ada lah dalam milimeter (mm). Ko imagine macam piston engine naik/turun la. Lagi jauh piston tu naik/turun, naik tinggi isipadu angin yang tolak/tarik. Sama juga macam subwoofer, lagi tinggi Xmax tu, lagi tinggi angin yang di tolak/tarik.
Bass lembut ni susah mo di dengar jadi untuk mendapat bass lembut yang kuat, Xmax yang tinggi ada lah di perlukan pada subwoofer tu.

BL - BL ni ada kekuatan motor subwoofer tu. Yang perlu di lihat di sini ialah BL curve sebab ia menunjuk kan linearity kekuatan motor tu. Lagi flat / rata BL curve tu, lagi low distortion subwoofer tu.

Sd - ini ialah keluasan permukaan subwoofer cone tu. Lagi besar Sd ni, lagi luas la permukaan subwoofer ni. Kira macam pakai piston engine yg besar

Vd - ini ialah displacement of air by the subwoofer. Vd = Sd x Xmax
Ini macam piston besar x stroke tinggi = cc engine ko besar. So lagi tinggi Vd ko, lagi besar isipadu angin yang di tolak/tarik.

Pe - ini la thermal power rating subwoofer ko eg. 200W RMS ka.. 1000W RMS kaa

Qtc - ini adalah jumlah keseluruhan control/damping pada subwoofer tu. Value Qtc ni yang kita check semasa design kotak subwoofer sebab ini yang menentu kan sama ada bass ko akan main lembut atau karas. Ini dapat menjimat kan kotak2 subwoofer yang di bikin tapi tidak di pakai sebab response bass dia ko tidak suka.

bnyk lg yg prlu aku bljr nie..

ok bro kippo...bro.....kippo kalau setting spl main 12x4....mcm mana bro

big box, large port area, high port tuning freq. , stable power supply voltage (big alternator & batteries), huge amount of power (to counter impedance rise near resonance freq.) and lots lots of money

boy_charger88 wrote:

kalau setting spl main 12x4....mcm mana bro

balik2 suda ko tanya soalan ni. Apa yg ko tidak paham dari segi main SPL?
ko kasi detail soalan ko tu dan saya cuba jawap apa yg saya tau.


main SPL ni bukan hanya kes kasi sumbat berapa banyak subwoofer ko dapat. Faktor2 penting yang banyak mempengaruhi SPL ni ada lah banyak. Kira macam racing jua, bukan engine power saja ko tengok.

kalau pemasangan tidak ngam, 12" x 4 biji subwoofer pun boleh kalah sama 1 biji 12".

cuba kita tengok kes mau pasang 12" x 4 subwoofer pada kancil :
- kancil ni badan kecil jadi kotak subwoofer di bahagi empat biji subwoofer menjadi lebih kecil. Bila kotak kecil, efficiency subwoofer ada lah rendah. Bila efficiency rendah, kena sumbat lebih banyak power.

- sekarang mau banyak power, jadi mau duit $$$$$ besar mau beli amplifier lebih kuat. Tapi amplifier besar ni mau karan banyak dan bila badan amp besar, mau tempat yg besar untuk di pasang kalau tidak pandai overheat sebab tidak sukup cooling. Bila ambil space besar, space untuk kutak subwoofer akan makin kecil.

- Alternator kancil ni kecil jadi nampak dapat menstabil kan voltage power supply sistem. Jadi kena tukar pergi alternator yang lagi besar. Tapi di sebab kan kancil ni badan kecil, engine bay punya space pun terhad untuk pasang alternator yang besar. Jadi cukup ka alternator yang besar sedikit saja untuk menampung power supply demand?
Bila pasang alternator besar, dia akan makan power dari engine. Jadi engine kuat makan minyak. Bila engine kuat makan minyak, masa parking engine tidak cukup cooling. Idle pun engine mungkin semput2 mau kasi jalan alternator besar. Macam mana mau settle?
Pakai alternator yg besar sedikittt saja? & lepas tu simpan banyak2 bateri.

- Bila pasang banyak bateri ni, dia makan lebih banyak space. Jadi lagi kurang la space yg ada untuk 4 biji 12" subwoofer tu. Dan kereta ko makin berat, kana upgrade suspension & ada $$$ untuk beli minyak.

- kes mau pasang sound deadening lagi?..

- and so on and on and on


you see, it is not just putting plenty of subwoofers to play SPL. You have to look the whole picture

ya bha bro charger..bnyk kli uda ko tnya mcm 2..tp xpa..spya lbh phm mgkn ble bha tnya blk2..hihi.bnyk uda kippo c trg 2..

ksmpulannya bro kippo nie kancil x ble men 4 bji utk SPL ka?

hehehheh...relek bro KIPPO.hehehe..ok2 saya cr soalan n kumpul soalan yg patut bru tnya bro kippo..hehe..sory bro..

mana2 kereta pun boleh ko pakai untuk pasang SPL install tapi ko kana pilih kereta mana yang terbaik.

kata kan ko pasang 4 x 12" di kancil, lepas tu saya pula p pasang 2 x 12" di wira aeroback. Sekali ambil dB reading, score saya lebih tinggi dari ko. tidak ko sakit ati?


tapi apa yang saya mo kasi terang kan tu ialah mau pasang 12" x 4 ni banyak faktor2 perlu di pertimbang kan. Kalau saya bagi saiz kotak sahaja dan port tuning, ni macam kasi pandangan separuh masak baa..

kalau keta iswara sesuaikah bro main 4x12..?

boy_charger88 wrote:

hehehheh...relek bro KIPPO.hehehe..ok2 saya cr soalan n kumpul soalan yg patut bru tnya bro kippo..hehe..sory bro..

ok tu bro. Ko kasi terperinci lagi soalan ko tu. Baru senang mo kasi penerangan.

lah blm tdo rupanya bro nie..hehehe.....mcm saya pnh nmpk brolah

boy_charger88 wrote:

kalau keta iswara sesuaikah bro main 4x12..?

boleh, apa ko mo buat? extreme atau daily driver ?

kalau mau extreme, cabut kerusi belakang supaya lebih banyak space.

kalau daily driver, space di boot tu agak kici untuk 4 biji 12". Kalau pasang saja, bass ko akan keras dan memerlukan amplifier yang kuat.

dan iswara ni perlu kana pasang sound deadening banyak. Kalau tidak, 'brrrrr' 'brrrrr' ja bunyi nya

kalau saya, bagus lagi pakai 2 x 15" tapi masi box saiz pun tidak optimum

boy_charger88 wrote:

mcm saya pnh nmpk brolah

ada ka? hehe
suda lama saya tidak beraksi jual kaset di kadai ni. Mau2 dakat 3 tahun suda oohh. Macam mana pla ko bleh nampak saya hehehe

apa 2 bro deadenig..? n kalau extreme byk keja kan bro..?

sound deadening ni macam tu Dynamat Extreme. Benda ni macam penampal atap tu yg aluminium + tar tu.
Dia kasi berat badan kereta tu supaya tidak begagar masa blast bass

ada wah dululah 2006..ms sy keja carwash dpatau2 2...keta bro inda silap prado warna ungu...ms 2 dlm nya ada wofer 15x4.....