hi all .can someone please help me out here.
if i have 4 ohm speakers plugged into the amp they will run louder than 8ohm speakers.
what are the results of mixing 4ohm subs with 8ohm speakers.
thanks steve
Full Version: 8 ohms and 4 ohms speaker set up
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hi all .can someone please help me out here.
if i have 4 ohm speakers plugged into the amp they will run louder than 8ohm speakers.
what are the results of mixing 4ohm subs with 8ohm speakers.
thanks steve
what i mean is what are the effects of running 4ohm subs and 8ohm speakers at the same time .
cheers
cheers
It depends how they are wired eg: Series, or parallel.
If you're just using external speakon, XLR or TRS (1/4 inch jack) connectors from the amp to the first speaker, and then "daisy-chaining" another speaker off of the first speaker (each side) then that would be "parallel" wiring, worrying the amp mildly (or badly on cheaper amps), with a resistance of 2.6666666666666665 (you can tell that I worked that one out in my head, right?
)
Normally only the mid~higher priced/spec'd amps will handle loads down to 2ohms (or 2.66666 ohms).
If your speakers have seperate + & - connectors on them, then you could use lots of single wires (simplest example) to connect them in "series". For speakers in series you add the impedances of the speakers together eg: 8ohms + 4 ohms presents the amp with a 12ohm load, which you would have to ensure your amp would drive continually (eg: A 7 hour gig). An amp offering 300watts at 8ohms, would offer approx 150watts at 16ohms, so probably around 200watts(ish) for 12ohms, but not to be tried unless the amp manufacturers offer stats above 8ohms.
You know, even before the calculations, suggesting that you run the 8 ohm speakers off one amp, and the 4 ohm speakers off of another amp, seemed like a good idea. After the calculations, its an even better idea.
If you're just using external speakon, XLR or TRS (1/4 inch jack) connectors from the amp to the first speaker, and then "daisy-chaining" another speaker off of the first speaker (each side) then that would be "parallel" wiring, worrying the amp mildly (or badly on cheaper amps), with a resistance of 2.6666666666666665 (you can tell that I worked that one out in my head, right?
)Normally only the mid~higher priced/spec'd amps will handle loads down to 2ohms (or 2.66666 ohms).
If your speakers have seperate + & - connectors on them, then you could use lots of single wires (simplest example) to connect them in "series". For speakers in series you add the impedances of the speakers together eg: 8ohms + 4 ohms presents the amp with a 12ohm load, which you would have to ensure your amp would drive continually (eg: A 7 hour gig). An amp offering 300watts at 8ohms, would offer approx 150watts at 16ohms, so probably around 200watts(ish) for 12ohms, but not to be tried unless the amp manufacturers offer stats above 8ohms.
You know, even before the calculations, suggesting that you run the 8 ohm speakers off one amp, and the 4 ohm speakers off of another amp, seemed like a good idea. After the calculations, its an even better idea.
If you wire speakers in series then you add the resitances like you say but as there is more resistance the amp will kick out less power,
so if an amp kicks out 300w@8ohms and if it sees a load of 16 ohms it will kick out less power probably around 150-200w
but if you wire 4 (8 ohm) speakers in parrallel the amp will now see a 4 ohm load so the 300w amp will now see 500w
This is what I have always thought but I might be wrong
so if an amp kicks out 300w@8ohms and if it sees a load of 16 ohms it will kick out less power probably around 150-200w
but if you wire 4 (8 ohm) speakers in parrallel the amp will now see a 4 ohm load so the 300w amp will now see 500w
This is what I have always thought but I might be wrong
ARGH! You're right...and I know it....see what happens when I get into Ohms law calculations at 2am... 
I'll edit my post above to correct this...
and hope that Jazzcat didnt wire his speakers up in series in the last 7 hours. 
The fact that the wattage (almost) doubles as the ohms (impedance) goes up, is a physics rule (and an advertising loophole) that manufactuers of cheap amps have loved for ages.
Now just think, if its that easy to mis-claculate and mis-type SERIES theory when you're tied, think what a pain in the neck it would be to wire speaker cab up in series in a hurry, every gig... That second 4/8 ohm amp looks more and more tempting by the minute.
I'll edit my post above to correct this...
and hope that Jazzcat didnt wire his speakers up in series in the last 7 hours. The fact that the wattage (almost) doubles as the ohms (impedance) goes up, is a physics rule (and an advertising loophole) that manufactuers of cheap amps have loved for ages.
Now just think, if its that easy to mis-claculate and mis-type SERIES theory when you're tied, think what a pain in the neck it would be to wire speaker cab up in series in a hurry, every gig... That second 4/8 ohm amp looks more and more tempting by the minute.
NOW I AM CONFUSED.
| QUOTE (jazzcat @ Jan 18 2004, 12:03 AM) |
| NOW I AM CONFUSED. |
Okay, the basics....
The closer you get to zero ohms the more power your amp will give. Although many Amps will only allow you to safetly go to 4 ohms, before they overload / protection circuitry kicks in. However the lower (in numerical figure) your ohms are, the more power your amp will deliver.
For instance take a typical 250W per channel amplifier...
250W RMS @ 4 Ohms
160W RMS @ 8 Ohms
95W RMS @ 16 Ohms
Anything between 4 - 16 ohms is okay, however I wouldn't go below 4 ohms - unless you amp states that its " 2 Ohms Stable" or anything above 16 ohms either since you may as well be running an hi fi amp.
Connecting a 4 ohm and 8 ohm speaker in parallel (Simply plugging each speaker into a socket of the amp / other speaker) is risky - the resulting impedance is below the typical 4 ohm threshold handled by the majority of amps.
I don't really recommend connecting mixed impedance speakers to any amplifier as it would ultimately make one speaker (the 4 ohm) louder than the other, and can make a system a little unstable. The majority of speaker drivers for professional use are 8 ohms as standard. There are drivers made by eminence / celestion which are available in 4 ohms and cabs by Carlsbro which can be obtained in 4 ohm impedance. However these are the exception rather than the rule
. Commonly 4 ohms drivers are used in Car / Hi-Fi / Surround sound applications, so please check that the driver is made for this sort of use.If your amp is a 4 ohm variety (most are) then only connect the one 4 ohm speaker to it and this will deliver its full rated power in any case. If you really must use this configuration then ensure that you wire the 4 ohm cab in SERIES with the 8 ohm one. However the impendence will increase from 4 ohms to around 6 ohms and the power from your amp is likely to decrease slightly as well - so you are actually better off (power wise) using the one 4 ohm speaker connected, rather than series connecting the 4 and 8 ohm together.
If you need two cabs per channel and don't want the hassle of series wiring - then just get 2 speakers each rated at 8 Ohms impedance.
I have attached a file detailing the wiring combinations. Its written for the hi-fi industry but the content is valid for pro and p.a use as well.
ok thanks for that. i have got all that now
.ok
i have peavey rx 500 subs (4ohm) and
peavey 2xt tops(4ohms).
as of today.
all 4ohms . but i still only have the warrior amp.about 125 watts at 4 ohms i think.
so i need to go back to my supplier and swap the amp for a better more powerful amp .
what sort of power should i be looking for in my new amp.
cheers jazzcat
yeah sorry chris,
i seemed to of lost the plot a bit.
jazzcat
i seemed to of lost the plot a bit.
jazzcat
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