DVC sub in series or parallel?

[Hyun]

hi, i got this scenario ...

if u could wire a double voice-coil sub, each coil at 4 ohms, in parallel or in series, and if the resultant impedance in parallel is 2 ohms, and series is 8 ohms,

 

assuming you have an equivalent power output at both impedances, which would u be wiser to use? technical support from the amplifier manufacturer advised 8 ohms because the current draw would be less. (less heat? less energy used. but less power output, they dont think so??)

 

the tricky thing is i'm able to get the same "RMS power rating" output at 8 ohms and at 2 ohms (it's in the design of the amp). it won't output more at 2 compared to 8. that's why it was advised by the manufacturer to use 8 ohms.

[Headshok]

hahaha.. aiyah.. leave ur sub and amp alone lah.. wanna play somemore, play with spkrs, sell of ur CDTs, sure got pple want one.. hahaaa

 

aniway, if u want, u can just series ur sub and listen for the difference lor.

 

have fun.. hehe

[Hyun]

so happened that i ask PG whether if i connect front 4 ohms, rear 2 ohms bridged, can or not, they say can. they also ask me why connect 2 ohms? they say better connect 8 ohms - lower current but same power. who knows, maybe amp run cooler too.

 

if want to try, i have to change the DVC wiring to be series instead of parallel.

 

in that case, the wiring should go like:

 

amp + terminal ----> coil 1 positive terminal ----> exit coil 1 negative terminal, wire join to coil 2 POSITIVE terminal ----> exit coil 2 negative terminal, wire join back to amp - terminal contact point.

 

is that right? what happens if u accidentally connect like this:

amp + term ----> coil 1 positive ----> exit coil 1 negative, join to coil 2 NEGATIVE ---> exit coil 2 positive, join to amp - ter

 

(in this 2nd example, u basically flip the 2nd coil connection.)

would the sound cancel each other out?

Edited July 21, 2006 by Hyun

[Headshok]

hehe.. in theory thats true, but u never noe, may sound different.. heheh..

 

aniway, u runnin active front now ah? what amp u usin for tweets? got urself another amp?

[Hyun]

i tied up active for a while cos i dismantled my sub to analyse the problem.

now reassembled sub liao, switch back passive.

no amp leh. remember, i SHORT OF ONE CHANNEL??? hehehe.

 

a bit regret last time never get the soundstream 5 channel amp. that one wun short of one channel hehehehe.

[Headshok]

hahaha..

 

see lah.. i tell u!!! u never buy, see lah.. never listen to me.. now regret rite? hahaha

 

nmind, i come back see got any goodies to recommend u.. heheh

[Ae86]

The power output of your amp cannot be the same if assuming that the voltage and resistance is constant.Assuming v=12v and r=4ohms i will be and v=i*r therefore i=3amperes whereas i will be 1.5amperes if connect into 8 ohms power will be lesser for the latter.If you connect the dvc woofer in 8ohms parallel the amp don't have to work too hard meaning lesser stress and longer life span.

[Hyun]

heh i also dun understand, so i'm sorry but i cannot exprain. the amp (phoenix gold) somehow outputs the same power whatever the impedance. and after i emailed the company, they confirmed that odd fact. they also advised me to use 8 ohms for lower current. but i dont know how the power is kept the same. if what they say is true, power is the same, current is lower at 8 ohms, don't tell me voltage has changed? perhaps they use a variable resistor in the amp to reduce voltage internally?

[Knighthunter]

There is relation between speaker impedance and wattage consumption. The higher the impedance of the speaker impedance the more voltage needed to generate required power (watt) to drive the speaker. The major reason is why car speaker is preferably running on low impedance is the limitation of the power supply generated by alternator & battery at 12-14V compared to home theather speaker which running on 8 ohm impedance because of the higher volatge availabe (110/220V). If you wired your sub at 8 ohm you simply won't get the kick, since the amp wattage will drop by half. I deally for DVC sub is to make it running on 2 ohm impedance if the amp able to carry 2 ohm load.

If the power is only able to handle 4 ohm and sub is wired at 2 ohm it will bust the transistors (mosfet).

[Hyun]

like i said, this amp is siao one.

so i dont know which is stressing the system more:

200wrms @ 2 ohms = hotter?

or

200wrms @ 8 ohms = cooler? or same? since output's the same and efficiency has not really changed, so heat generated is no different?

 

maybe heat generated is the same, but current running at 8 ohms is lower?

power = current^2 x impedance

since power and impedance are constants, the current must drop, but overall power (heat) remains the same .. hmm.

 

only one way to find out, lemme wire in series once i get the chance.

[Ivan0507]

here just an e.g.

 

A 2-channel amplifier gives you outputs for two speakers, but that doesn

[Headshok]

eeh. by right(in theory) at 8ohms, ur amp should be puttin out the same amt of power at 2ohms (becos of how ur amp was made, its differnt from other amps)

 

BUT by left, what really happens inside the amp when u hook it up to 8 ohms we dunno, only the engineers at PG know.

 

SO, just try to hook it up at 8ohms and listen lor..

[Knighthunter]

The amp rating is moving opposite impedance giving the power supply is constant at 12V (in car case).

Amp rating at 100 W at 8 Ohms will be equivalent to 200 W at 4 Ohms, 400 W at 2 Ohms, 800 W at 1 ohm. But all this limited by the power itself, some top of the line or D class amplifier stable at 1 ohm.

In you case if you amp is able to give similar rating at 8 ohm and 2 ohm, there is possibility this amp has switching voltage converter build in. The circuitry will switching at high voltage for output at 8 ohms and switching to lower voltage for 2 ohms. I am not sure about this, since I don't know what amp you use.

The heat is not related to the impedance of the speaker but related to the amplification factor. The higher the amplification factor the more heat generated by amp.

[Knighthunter]

I am sorry bro, see my post above. Normal car amplifier will not giving same rating if the speaker impedance is lowered.

[Kanr]

very true,bro!!Thks for yr Info,bro!!!

[Headshok]

yo bro,

 

check out the specs on the Phoenix Gold Xenon amps. its rated to push out the same power regardless of impedence.

 

in hyun's case. its either 2 or 8 ohms cos his is 4 ohm DVC.

 

this is a rather unusual "design".

 

JL amps are also similiar if i'm not wrong.

 

that is why i said by right it is suppose to push out the same power at 8ohms or 4 ohms for hyun's setup.

 

but whether it really pushes out the same power at 8ohms, only the engineers at PG know. so best for him to test it out and listen for difference.

 

as for your voltage theory, thats something new. cos i know there is high current., most amps out there usually are not stable at anything 'higher' than car voltage(ie.14.4).

 

amps that are stable at anything higher that 14.4 are competition amps.

 

cheers.

Edited July 27, 2006 by Headshok

[Ivan0507]

headshok,his case was,bridging the 3 & 4 ch to one . i think the sub should hook up to 8ohm since is dvc 4 ohm. cos i never see a amp 4ch(bridge ) can stable at 2ohm for 3rd channel.

[Headshok]

yo ivan,

 

i know hyun's case cos i often meetup with him at the ICE meetup

 

This is the spec for PG's Xenon 200.4:

 

200 watts x 4 (1-4 ohms stero)

400watts x 2 (2-8ohms bridged)

 

hyun's current setup now is 2 channels pushin front spkrs and 2 channels bridged to power his 4ohm DVC sub.at present, he's drivin the sub at 2 ohms (coils paralleled)

 

So hyun lately backside itchy want to series his sub to 8ohms and power it. in theory according to the specs of the amp, it is suppose to push out the same power. but this is someting 'unusual' to most pple.

 

 

 

I know one guy who was using the PG 1200.1 amp, which pushes 1200 watts from 1-4 ohms. he pushed his 700 watt sub(2ohm DVC) @ 4ohms and it HIT HARD(and he's using a box u made, good box man!!

 

aniway, ur avatars never fail to make me drool sia.. hahah.. keep up the good work man!!