A Question For The Audiophiles

Heavy_Equipment · 08-17-2002, 11:43 AM

I bought a Kenwood home theatre setup last year for my PC sound system, and like everything else, after buying the receiver, satellites, and centre, (package) I had limited funds left for a set of main (stereo) speakers. I picked up the best pair of craptastic towers that I could afford back then.
Upgrade time.

The receiver calls for an 8 ohm or higher speaker, and I was wondering if 4 ohm would actually work.
Anybody use 4 ohms and get away with it?

I live in a basement apartment, so it only gets cranked for short stints when no one is home upstairs, otherwise it's medium to low for the everyday mp3/dvd/gaming. The amp is thermally protected too.

I had problems with amps cutting out back in high school, when I wired the car in series to get down to 2 ohms...but that was also 1200 watts, and crank it up and throw away the knob type use.

...and yes, most of my conversations now do involve me using the word 'pardon?' one or two times.

bigben2k · 08-18-2002, 04:36 PM

Arrgh! Can't resist... must answer...

No, don't do it. Your amp was designed for 8 Ohm impedence, not 4 Ohm. If you hook up the 4 Ohm, you'll draw twice the current from your amp, for the same voltage, which is something it wasn't designed to do. You'll blow the main transistors, and that's half the amp right there.

On the other hand, you might get lucky, if you keep the volume down, but that would defeat your objective... so... Don't do it!

If you want 8 Ohms, you could always hook up those speakers in series, on a single channel. That would work nicely.

Heavy_Equipment · 08-18-2002, 07:21 PM

Actually, unless I'm misunderstanding you, wiring in series does the opposite.

Wiring two 8 ohm speakers in series would give 4 ohms...two 4ohm units would give you 2ohms.

I have a plan A and B devised here.

Plan A involves me trying the 4 ohm subs, (since I have them already) with a fan added behind my receiver. Some receivers are well under rated to protect the manufacturer I have just been told, just not sure if Kenwood uses that same approach. I suspect they might, because this unit runs very cool.

If the amp thermally cuts out, then I'll stop.

Plan B inivolves leaving the 4 ohm subs in the case, but running a separate channel to them from a separate amp, off the sub out jack.

A is my cheaper/simplest option, but B builds off it, so no big waste of time.

Trying to make the most out of the parts/equipment I have already.
Kind of the mind set that got me into overclocking too.

c0dy · 08-18-2002, 09:26 PM

if the speakers are rated 4 ohms and the amp is 8 then you should be safe.. if it was the other way around id worry..

mkosem · 08-18-2002, 11:22 PM

cody, you got it backwards.

Actually, most home recievers/amplifiers these days are made to handle 4 ohms. This is because many of them include hook-ups for additional pairs of speakers powered by the same channels and usually accesable by buttons or switches. Provided that reciever does posess that trait you should be more than fine to run with the 4 ohm speakers. I have a Pioneer Reciever and the owners manual even lists the power outputs with different impedences of speakers. You should check with the manufacturer of the amp to be sure but it should not be a problem.

--Matt

bigben2k · 08-19-2002, 08:46 AM

The Harmon Kardon are usually under rated, so check your manual otherwise.

If you hook up 8 Ohm speakers in parallel, then you'd get a total resistance of 4 Ohm. If you connect 4 Ohm in series, then you'll have 8 Ohm. So ideally, you'd use 2 x 4 Ohm speakers in series for each channel (he he he).

If you're considering using the sub channel, then you'd be all set, as the sub channell is mono, not stereo, so you could go ahead with plan B, and hook up the subs in series to the sub channel.

DigitalChaos · 08-19-2002, 02:09 PM

yes, just like 2 water blocks.
put them in parallel and you have less resistance in the line
put them in series and you have more resistance in the line.

Heavy_Equipment · 08-19-2002, 05:17 PM

The sub channel route, is simpler, but more costly...it's pre amp.

I don't need a powered sub with the towers...12" subs are part of the package, and the amp drives hard enough...not Harman-Kardon hard, but also not H-K price

(As tested with a set of Cerwin-Vega's at my buddies house...wanted to make sure this receiver had some balls when I got it, they don't quit let you test receivers properly at the mall)

I'd sooner spend the money on GOOD 8 ohm subs for the towers, like the 12" Cerwin's, since I don't have anywhere to put a powered stand alone anyway.

Sigh, but that takes me back to money I'm trying not to spend in the first place.

c0dy · 08-19-2002, 05:51 PM

i thought that because if 4ohms is less resistance than 8 correct? and if the speaker can handle less resistance/current than it should be safe... right?? lol wow im just confused.. anyone care on clarifying this out for me??

Heavy_Equipment · 08-19-2002, 06:22 PM

If you use a lower load, (=resistance, measured in ohms) than rated, the amplifier will be over-driven, causing it to over heat.

Just like opening a tap... by using 4 ohms instead of 8, you are increasing the "flow" (amperage) the amp has to produce.

Ohm's law dictates that by lowering the resistance, with the same voltage, you will increase the amperage. (current)

This also increases your watts. (volts x amps)

*EDIT*

Forgot to answer the first part of your question.
Yes, 4 ohms is lower than 8, but you ARE confused aren't you.

It's the opposite... it's the speaker's load (resistance) that the amp has to handle. A lower resistance means a higher demand.

You're confusing this with the wattage(power) the speaker can handle.

So to recap: The wattage is produced by the amp, the resistance is "produced" by the speaker.

bigben2k · 08-20-2002, 08:11 AM

Quote:

Originally posted by c0dy
i thought that because if 4ohms is less resistance than 8 correct? and if the speaker can handle less resistance/current than it should be safe... right?? lol wow im just confused.. anyone care on clarifying this out for me??

The answer is V=RI, where v is the voltage, R is the resistance (in Ohms), and I is the current, in amps.

If you lower the resistance, and because the voltage remains constant (it's how the volume is set), then you just doubled the amps.

P=VI

Power (in Watts) = Voltage * Amperage.

So if you double the amperage, you just doubled the power drawn from the amp.

c0dy · 08-20-2002, 06:15 PM

:shrug: thanks for clearin that up for me

08-17-2002, 11:43 AM	#1
Heavy_Equipment Cooling Savant Join Date: Mar 2002 Location: Newmarket, Ontario, Canada Posts: 282	A Question For The Audiophiles I bought a Kenwood home theatre setup last year for my PC sound system, and like everything else, after buying the receiver, satellites, and centre, (package) I had limited funds left for a set of main (stereo) speakers. I picked up the best pair of craptastic towers that I could afford back then. Upgrade time. The receiver calls for an 8 ohm or higher speaker, and I was wondering if 4 ohm would actually work. Anybody use 4 ohms and get away with it? I live in a basement apartment, so it only gets cranked for short stints when no one is home upstairs, otherwise it's medium to low for the everyday mp3/dvd/gaming. The amp is thermally protected too. I had problems with amps cutting out back in high school, when I wired the car in series to get down to 2 ohms...but that was also 1200 watts, and crank it up and throw away the knob type use. ...and yes, most of my conversations now do involve me using the word 'pardon?' one or two times.

08-18-2002, 04:36 PM	#2
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Arrgh! Can't resist... must answer... No, don't do it. Your amp was designed for 8 Ohm impedence, not 4 Ohm. If you hook up the 4 Ohm, you'll draw twice the current from your amp, for the same voltage, which is something it wasn't designed to do. You'll blow the main transistors, and that's half the amp right there. On the other hand, you might get lucky, if you keep the volume down, but that would defeat your objective... so... Don't do it! If you want 8 Ohms, you could always hook up those speakers in series, on a single channel. That would work nicely. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

08-18-2002, 09:26 PM	#4
c0dy Cooling Neophyte Join Date: Aug 2002 Location: Groton, CT Posts: 4	if the speakers are rated 4 ohms and the amp is 8 then you should be safe.. if it was the other way around id worry.. __________________ Abit KR7A Athlon XP Agoia 1800+ 11.5*151 Gainward Geforce3 Ti200 @ 261/550

08-18-2002, 11:22 PM	#5
mkosem Cooling Savant Join Date: May 2001 Location: here Posts: 494	cody, you got it backwards. Actually, most home recievers/amplifiers these days are made to handle 4 ohms. This is because many of them include hook-ups for additional pairs of speakers powered by the same channels and usually accesable by buttons or switches. Provided that reciever does posess that trait you should be more than fine to run with the 4 ohm speakers. I have a Pioneer Reciever and the owners manual even lists the power outputs with different impedences of speakers. You should check with the manufacturer of the amp to be sure but it should not be a problem. --Matt __________________ If you can't cool it, blow it up!! http://www.mattkosem.com

08-19-2002, 08:46 AM	#6
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	The Harmon Kardon are usually under rated, so check your manual otherwise. If you hook up 8 Ohm speakers in parallel, then you'd get a total resistance of 4 Ohm. If you connect 4 Ohm in series, then you'll have 8 Ohm. So ideally, you'd use 2 x 4 Ohm speakers in series for each channel (he he he). If you're considering using the sub channel, then you'd be all set, as the sub channell is mono, not stereo, so you could go ahead with plan B, and hook up the subs in series to the sub channel. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

08-18-2002, 07:21 PM	#3
Heavy_Equipment Cooling Savant Join Date: Mar 2002 Location: Newmarket, Ontario, Canada Posts: 282	Actually, unless I'm misunderstanding you, wiring in series does the opposite. Wiring two 8 ohm speakers in series would give 4 ohms...two 4ohm units would give you 2ohms. I have a plan A and B devised here. Plan A involves me trying the 4 ohm subs, (since I have them already) with a fan added behind my receiver. Some receivers are well under rated to protect the manufacturer I have just been told, just not sure if Kenwood uses that same approach. I suspect they might, because this unit runs very cool. If the amp thermally cuts out, then I'll stop. Plan B inivolves leaving the 4 ohm subs in the case, but running a separate channel to them from a separate amp, off the sub out jack. A is my cheaper/simplest option, but B builds off it, so no big waste of time. Trying to make the most out of the parts/equipment I have already. Kind of the mind set that got me into overclocking too.

08-19-2002, 02:09 PM	#7
DigitalChaos Cooling Savant Join Date: Jan 2002 Location: Waukesha, Wi Posts: 698	yes, just like 2 water blocks. put them in parallel and you have less resistance in the line put them in series and you have more resistance in the line. __________________ http://www.digitalsimplicity.com/eatme/

08-19-2002, 05:17 PM	#8
Heavy_Equipment Cooling Savant Join Date: Mar 2002 Location: Newmarket, Ontario, Canada Posts: 282	The sub channel route, is simpler, but more costly...it's pre amp. I don't need a powered sub with the towers...12" subs are part of the package, and the amp drives hard enough...not Harman-Kardon hard, but also not H-K price (As tested with a set of Cerwin-Vega's at my buddies house...wanted to make sure this receiver had some balls when I got it, they don't quit let you test receivers properly at the mall) I'd sooner spend the money on GOOD 8 ohm subs for the towers, like the 12" Cerwin's, since I don't have anywhere to put a powered stand alone anyway. Sigh, but that takes me back to money I'm trying not to spend in the first place.

08-19-2002, 05:51 PM	#9
c0dy Cooling Neophyte Join Date: Aug 2002 Location: Groton, CT Posts: 4	i thought that because if 4ohms is less resistance than 8 correct? and if the speaker can handle less resistance/current than it should be safe... right?? lol wow im just confused.. anyone care on clarifying this out for me?? __________________ Abit KR7A Athlon XP Agoia 1800+ 11.5*151 Gainward Geforce3 Ti200 @ 261/550

08-19-2002, 06:22 PM	#10
Heavy_Equipment Cooling Savant Join Date: Mar 2002 Location: Newmarket, Ontario, Canada Posts: 282	If you use a lower load, (=resistance, measured in ohms) than rated, the amplifier will be over-driven, causing it to over heat. Just like opening a tap... by using 4 ohms instead of 8, you are increasing the "flow" (amperage) the amp has to produce. Ohm's law dictates that by lowering the resistance, with the same voltage, you will increase the amperage. (current) This also increases your watts. (volts x amps) EDIT Forgot to answer the first part of your question. Yes, 4 ohms is lower than 8, but you ARE confused aren't you. It's the opposite... it's the speaker's load (resistance) that the amp has to handle. A lower resistance means a higher demand. You're confusing this with the wattage(power) the speaker can handle. So to recap: The wattage is produced by the amp, the resistance is "produced" by the speaker. Last edited by Heavy_Equipment; 08-20-2002 at 03:16 PM.

08-20-2002, 06:15 PM	#12
c0dy Cooling Neophyte Join Date: Aug 2002 Location: Groton, CT Posts: 4	:shrug: thanks for clearin that up for me __________________ Abit KR7A Athlon XP Agoia 1800+ 11.5*151 Gainward Geforce3 Ti200 @ 261/550

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