4, 6, 8 ohms?

[reynolr]

I just recieved and hooked up my Onkyo HT-RC180 and when I hooked up my front L/R mains the only options for the ohms is 4 and 6. I don't know if this is a problem or what, on the klipsch website it says that my rf-52ii's are 8 ohms. If I am running 6 ohms on my reciever is that ok? Let me know because I do not what to ruin anything. Thanks.

[db101]

No worries, it's ok to run your 8 ohm speakers with the 6 ohm output from the receiver, however I find it kind of odd that you don't have 4 & 8 ohm outputs on the Onkyo. Where people get into trouble is trying to run 4 ohm speakers off of an 8 ohm tap on the amp, because the amp has to work much harder to power the speakers.

[garyrc]

It's so weird for them not to have speaker binding posts marked 8 Ohms .... especially when their own specs for power output are referenced to 8 Ohms. It does seem to me that using the 6 Ohm output would be O.K., but this is so odd it might be worth an email or phone call to Onkyo to see what their explanation is.

[willland]

No worries, it's ok to run your 8 ohm speakers with the 6 ohm output from the receiver, however I find it kind of odd that you don't have 4 & 8 ohm outputs on the Onkyo.

My Onkyo TX-SR705(2007 model) has 4ohm and 6ohm settings. Recommending a 6ohm setting may be because Onkyo wants to squeeze a little more power out of their receivers to better drive low efficient speakers and to handle the low impedence dips that it may encounter. Just a thought. Onkyo receivers do run a tad warmer than most and a 6ohm setting may just be the reason.

Bill

[Trey Cannon]

The real answer is to use the 4 Ohm setting...This is the min. that the speaker will show the amp...if the amp is expecting it you should never have a problem.

The speakers are 8 Ohm compatible but the min Z is about 4 Ohms.

A speaker does not have one "Ohm rating" . Ohm's here are talking about impedance and that changes with frequency. So at 110 Hz it may be 60 Ohms and at 300 Ohms it may be 4 Ohms.

One number just does not cut it. Thus the "compatible" ....and not "Nominal" want some fun..look up the word "nominal"

Have a good weekend.

[JasonJCarney]

If the impedance of any speaker is 4 ohms or more but less than 6, set the minimum speaker impedance to 4 ohms. That is a quote from my onkyo manual. If Klipsch are 8 ohm speakers than shouldn't I be setting my AVR to the 6 ohm setting?

[Ski Bum]

http://www.audioholics.com/education/amplifier-technology/impedance-selector-switch-1

[delhite2]

hi
well as far as i can remeber 4 ohms settings is for speakers which have impedance between 4-6 ohms and

6 ohms settings is for speakers which have impedance between 6-16 ohms.

regards

[djk]

I agree with Trey, use the 4Ω setting.

[Islander]

I agree with the audioholics article. Use the 6 or 8 ohm setting, whichever is higher. The 4 ohm setting limits power in the amp, with the result that it's easier to go into clipping when playing at high volume, and bass notes will sound thin at all volume levels.

When I bought my Yamaha RX-V750 AV receiver a few years ago, I dutifully set the impedance switch at 4 ohms, since my speakers at the time were marked "4-8 ohms". The sound was quite disappointing, until I finally clued in and switched it to 8 ohms and then got the good sound I'd been expecting from the first. I was able to set the bass back to 0 from +3db, so that will give you an idea of the difference.

[djk]

"and bass notes will sound thin at all volume levels."

The converse is usually true.

For longest life and best reliability, set the impedance switch to the minimum impedance of the speaker.

"If this system is using a turntable, and if
there is a slight warp to the record, the combination of phono cartridge
and
RIAA equalization curve may be producing a demand for output at 15Hz
from the
amplifier/loudspeaker combination that could be larger in magnitude than
the
entire audible musical spectrum! "

This guy doesn't have a clue.

The region you want to examine closely is the broad minimum around 200hz or so, the dip that guy is getting all worked up about below 10hz is meaningless (that speaker looks to be ported to about 48hz and will roll-off hard below there, I would use a filter at 40hz on this speaker to prevent damage).

[Islander]

"and bass notes will sound thin at all volume levels."

The converse is usually true.

For longest life and best reliability, set the impedance switch to the minimum impedance of the speaker.

"If this system is using a turntable, and if there is a slight warp to the record, the combination of phono cartridge and RIAA equalization curve may be producing a demand for output at 15Hz from the amplifier/loudspeaker combination that could be larger in magnitude than the entire audible musical spectrum! "

This guy doesn't have a clue.

I didn't read all of that article, but the turntable part does seem a bit far-fetched. However, I was speaking from personal experience. The impedance switch on Yamaha receivers has come up on this forum a number of times, and on other forums as well. The general consensus is that with Yamaha receivers, the best bet for good sound is to leave the switch in the 8 ohm position. It seems that the 4 ohm setting is for increased safety in the case of inadequate ventilation of the receiver, but is not actually needed. Very few receiver manufacturers feel there is any need for such a switch.

As for thin-sounding bass, isn't that what you would expect with reduced power and reduced headroom? It was certainly the case with my receiver.

It could be that Onkyo receivers behave differently. I have no experience with them.

[artto]

The real answer is to use the 4 Ohm setting...This is the min. that the speaker will show the amp...if the amp is expecting it you should never have a problem.

The speakers are 8 Ohm compatible but the min Z is about 4 Ohms.

A speaker does not have one "Ohm rating" . Ohm's here are talking about impedance and that changes with frequency. So at 110 Hz it may be 60 Ohms and at 300 Ohms it may be 4 Ohms.
One number just does not cut it. Thus the "compatible" ....and not "Nominal" want some fun..look up the word "nominal"


Have a good weekend.

Just take Trey's advice. Unless you're dealing with multiple speaker systems in some kind of P.A setup, if your amplifier/receiver has taps for different impedance in the typical range of home speakers (say 4-16 ohms), just use the 4 ohm tap and forget it. Your amplifier will thank you.

[djk]

"As for thin-sounding bass, isn't that what you would expect with reduced
power and reduced headroom? "

No.

You hear thin sounding bass when you run out of current, the switch reduces power supply voltage.

On a tube amplifier it will always play loudest on the 16Ω tap (at low volume levels), but it will have the best bass (and overall sound) on the tap that is the closest match to the actual impedance.

[JJkizak]

I seem to recall that PWK didn't think setting an impedance value was as easy as stated in this thread. The whole frequency spectrum was studied and an average value was used and then it was tested a whole bunch. And if that didn't work they would try something else.

JJK

[garyrc]

"If this system is using a turntable, and if
there is a slight warp to the record, the combination of phono cartridge and
RIAA equalization curve may be producing a demand for output at 15Hz from the
amplifier/loudspeaker combination that could be larger in magnitude than the
entire audible musical spectrum!"

Back in about 1982, I was told I didn't need a subsonic filter (even though the dealer carried them) to protect speakers from producing distortion and/or damage, even with warped records, specifically because I had Klipschorns. Since then, I heard that horns "unload" below the lowest usable frequency (about 35 Hz for the Khorn). Does this mean that if I were to play a warped record, my woofers would flap back and forth in a distorting and dangerous way? We sometimes have our L & R fronts (Khorns) set on "large" or full range when playing movies. Given the terrific amount of deep bass on some soundtracks, is this putting our Khorns in danger? By the way, the only tap we have is 8 Ohms.

[djk]

Somewher in the 70s the RIAA curve changed and incorporated a subsonic roll-off.

All vented systems should be used with some sort of filter.

A true horn with a sealed rear chamber does not need a fliter per se, but it doesn't hurt to have one.

The top photo shows a true horn with a sealed rear chamber, the bottom shows a horn that does not have a sealed rear chamber. See how the excursion compares?

[reynolr]

Just to let ya all know what I did... I had them orginally at 6 ohms, then switched them over to 4. I honestly could not tell a difference bt either at any volume level or any mode (dolby, stereo, ect). So apparently it isn't to big a deal? I just hope nothing is going on on the inside that is messing up my speakers. Anyways they are currently on 4 ohms. I'll give it a little and switch is back to 6 to se if I can hear a difference after extended use. Thanks for the posts.

[sivadselim]

Just take Trey's advice

Why? Trey is wrong. []

As pointed out in the thread and, more specifically, in the Audioholics link that was linked to in Ski Bum's post, the 4ohm setting provided on mid-level recievers and amps does nothing but throttle back the amps' output so as to provide a modicum of protection when they are driving 4ohm speakers. That switch doesn't make the amps magically operate at 4ohms. The impedence at which an amp operates is dictated by the speaker it is driving.

To people with a 4ohm and 8ohm setting, but driving 4ohm speakers, I would recommend at least trying to use the standard 8ohm setting, if at all possible, as this will provide the most power to the speakers. Yes, the 4ohm speakers will force the receiver to operate at 4ohms, but many receivers are robust enough to handle that nowadays. The 4ohm setting in this situation does nothing but send less power to the speakers thereby reducing the amount of heat produced and thereby reducing the chance of the amps going into a thermal protection mode. But no matter what, whether the 8ohm or 4ohm setting is used, the receiver will still be operating at the impedance presented by the speakers (in this example, 4ohms - nominal, of course).

And the advice to use a 4ohm setting with an 8ohm rated speaker just because the impedence probably dips well below 8ohms with that speaker is, quite frankly, terrible advice. Terrible. If a speaker is nominally rated at 8ohms then any receiver should be able to drive them just fine operating at its standard 8ohm setting regardless of any impedence dips presented by the speakers. The 4ohm setting in this instance will ONLY serve to diminish the performance of one's system.

[djk]

Hey sivadselim, you going to spring for any repairs needed from your bad advice?

The impedance selector lowers the supply voltage to try and keep the amplifier in one piece over time.

"The 4ohm setting in this instance will ONLY serve to diminish the
performance of one's system."

Sure, it might knock off 1.5dB or so when you run it up to clipping..

Big whoop-te-do.

Please post your name and address for those people that take your advise and their amplifier blows up and takes out their woofers at some point down the road.

On second though, take his advise, the service guys need the work.

(ex service manager authorized tor McIntosh, Yamaha, Nakamichi, Denon, Crown, Harman Kardon, Sony, Tandberg, you name it)