Derek's Speaker Series/Parallell/Impedance Quandry

[derek92994]

Very, Very loud, about 120 db or the eyeballs vibrate, whichever comes first.....

That's the spirit, the neighbor has kittens with the current pioneer amps I have, imagine what's going to happen with the PL Will it run stable at 4 ohms if I add fans?

 

[laatsch55]

Yes, and do about 740 watts RMS per channel at 4 ohms...

 

[derek92994]

Yes, and do about 740 watts RMS per channel at 4 ohms...

That's insane, I will have to show some restraint for the health of my speakers. I have two pioneer towers (dual 6 inch drivers) rated at 185 watts, two technics 8 inch drivers rated at 100 watts, and the two 12's I am not sure what they are rated at. Not sure exactly what to do in this situation. Parallel or series? Or just run the 8's and 12's and do without the towers, tough choice as the towers have great horns/high range. This is what I will have to run until I get some JBL studio monitor speakers that are designed to handle the power.

 

[laatsch55]

The beauty of that much clean power is dynamic headroom. Speakers will take a hell of a transient if it's clean. Everything sounds a little better with lots of headroom. And that 740 was the last measurement we had at 5 amp fuses per rail. The manual calls for 8 amp rail fuses for sinewave testing, I'm guessing it will bounce off the 800 mark if I had balls enough to stick some 8 ampers in there.

 

[derek92994]

The beauty of that much clean power is dynamic headroom. Speakers will take a hell of a transient if it's clean. Everything sounds a little better with lots of headroom. And that 740 was the last measurement we had at 5 amp fuses per rail. The manual calls for 8 amp rail fuses for sinewave testing, I'm guessing it will bounce off the 800 mark if I had balls enough to stick some 8 ampers in there.

Guess I should just try hooking up all 3 types of speakers into series so the ohms don't go bananas with the PL? I don't know much about this stuff as am running them on individual channels on the two pioneer amps A/B on one, and B on the other.

 

[laatsch55]

If they are 4 ohm speaks, NO PARALLEL. In series they would be 180 degrees out of phase with each other.

 

[derek92994]

If they are 4 ohm speaks, NO PARALLEL. In series they would be 180 degrees out of phase with each other.

I think they are all 8 ohm speakers, the Pioneer towers don't specify so I am assuming there. The technics and auditone 12's I am sure of being 8 ohms.

 

[laatsch55]

You could parallel a couple of those. The one thing though, speakers do not present that 8 ohms at all frequencies. On some hard to drive 4 ohmers you can seew dips to 1-1/2 ohms, those are what get ya. Do you have a frequency response plot for any of your speaks??

 

[derek92994]

You could parallel a couple of those. The one thing though, speakers do not present that 8 ohms at all frequencies. On some hard to drive 4 ohmers you can seew dips to 1-1/2 ohms, those are what get ya. Do you have a frequency response plot for any of your speaks??

No I know nothing about this stuff, give me a bit I will take some photos for you. Maybe this will help sort this out.

 

[derek92994]

I was just thinking if any of these were 4 ohms, the pioneer amps would be freaking out as I have the impedance selector at 8 ohms or more (rear switch on the amps). They don't get hot and drive the speakers with ease. Anyways here are the photos, maybe you could shine some light on this.

 

[pennysdad]

I was just thinking if any of these were 4 ohms, the pioneer amps would be freaking out as I have the impedance selector at 8 ohms or more (rear switch on the amps). They don't get hot and drive the speakers with ease. Anyways here are the photos, maybe you could shine some light on this.

measure each speaker first with a DMM, and just write down what they measure in Ohms, and report back here with your findings, or my thread if we respect 'staying on topic' rules here.

 

[Oktyabr]

No speaker presents a constant 8 ohm load, or any other impedance for that matter, not in the real world playing real music. Since the impedance of a given speaker is variable the amps that drive them must be adaptable to different impedance as well. "8 ohm" and "4 ohm" ratings on consumer grade amplifiers are given as part of it's UL listing requirement (in the USA anyway) and in the case of *most* manufacturers it's safer to make conservative ratings rather than risk getting sued because someone's house burned down. In other words it's better to build an amplifier that's perfectly capable of running 2, 4, or 6 ohms all day long and then rate it for 8 ohms with bold printing stating "Do NOT run any speakers lower than 8 ohms", etc.

Unlike the amplifier business it's safer for speaker manufacturers to rate impedance conservatively the other way instead. No one really wants to build a speaker that could develop a reputation as an "amp killer" (wassup Infinity?!?) so it's better to rate a speaker as presenting a lower impedance than higher, with the hopes that the speakers will be matched with a suitably stout amplifier. Most consumer grade speakers under $1000 that *don't* include a listed impedance rating are typically designed for use with a consumer grade amplifier as well, i.e. an "8 ohm" rating. There was a big battle of marketing spanning several decades where all the major companies were trying to figure out what the standard should be... Everything from 4 ohms up to 16 ohms were at one time considered the standard. With the advent of home theater systems, primarily the budget HTiB ("Home Theater in a Box") 8 ohms seems to have been settled on as the standard, more or less.

Long story made short? In my opinion all of the speakers in your photos should be happy plugged into just about any amplifier, given that they are not overdriven. YMMV.

 

[jbeckva]

Figured we'd move this over and out of the "What are you listening to" section... Good topic and we should make sure it doesn't get lost out there..

Yeah Lee didn't think series was quite the way to go here, but yanno there are plenty of low power amps out there that force you into a series operation when you switch the outputs to "A+B", etc..

Now although "impedance" isn't quite the same (really it's akin to "resistance of the load at a certain frequency, which varies from 20 to 20", right?), on a very basic level I'd be a lil concerned about 3 pairs in parallel (2, not so much... )

If we apply good ole Ohm's law to it... considering we hope that all 3 are 8 ohms nominal .. That's 2.7 ohms presented to the amp's output. Is the PLWO going to be stable at that level.. I'll let Lee and Joe give the final verdict, but from what I recall .. no.. don't do it.

Remember it varies with frequency... so (gawd forbid) if at 8000hz impedance drops to an average of 3 ohms... with 3 in parallel, that would be 1 ohm. That would equal A LOT of current demand from the amp, considering (if I recall?) the base design of the PL amps already warns that with 4 ohm loads that fans be installed, and to NOT go any lower.

As Lee said... 2 pairs MAX in parallel and maybe/as long as you have good ventilation / cooling on the back of the amp. And they should be 8 ohms min.

 

[derek92994]

Hey guys

Thanks so much for your help and for creating a thread for this, I should have done this in the first place but had a few too many beers last night, was celebrating the end of the working week I need to find out what a DMM is, have PMed lee about this as I did not see this thread until now. I know from previous experience that running in Parallel caused problems with heat in amps, and I have avoided doing that for many years as the amps I have used have not been all that tough. At the moment the two pioneer 9500s amps have the pioneer towers and technics (8 inch) on A/B channel, with the 2nd amp running the Auditone 12's on the B channel (not sure if the A channel works, that amp has problems). These amps have a reputation for running hot as is so they are fan cooled but even still are not under that much strain.

Just trying to get the facts straightened out for when I purchase the PL 700 (enhanced by lee) and want to get it right. So as it stands you suggest two pairs in Parallel, the problem is the Pioneer towers have great high range due to the horns in them (or are they just really good tweeters?), would like to run them and the auditone 12 inch drivers in parallel but would the 12's still get sufficient power for a decent drive without blowing up those small pioneers? If this is a problem I could just do without the great high range from the horns and run the technics 8's and auditone 12's in parallel. What would you suggest?

 

[laatsch55]

One set of really good speakers?????

 

[laatsch55]

or my thread if we respect 'staying on topic' rules here.




That's some funny shit there BD...

 

[derek92994]

One set of really good speakers?????

One thing at a time, will get the amp first then start saving again for the speakers. My wage is very poor. Will get back to you re multimeter, will take a pic and show you what I have. Just doing some simulation racing at the moment with my usa friends. =)

 

[laatsch55]

cool....

 

[pennysdad]

or my thread if we respect 'staying on topic' rules here.




That's some funny shit there BD...

Well, you know me, Lee, anything for a larf, and 'Derek", a DMM is a Digital Multi Meter.

 

[laatsch55]

Wow BD, we agree on something.....