gibby214 Posted February 18, 2005 Share Posted February 18, 2005 Are the Reference Klipsch ratings correct @ 8 Ohms? Did some research on my RB 75's. Home Theater mag graph shows 3.56 Ohms @ 200Hz. Also RC 7's 3.32 Ohm's @ 174Hz. http://www.hometheatermag.com/loudspeakers/1103klipsch/index1.html I don't remember exactly but I recall a recent post rating the mighty RF 7's at about 2.8 Ohms??? Is that Nominal or Compatible verbage just average across freq's? Would I be better setting my reciever to 6 Ohms vs 8 Ohms to handle the load. Thanks Gib Quote Link to comment Share on other sites More sharing options...
organ Posted February 18, 2005 Share Posted February 18, 2005 The 8 Ohms rating is nominal. Pretty much an average rating. The impedance will dip and rise depending on the frequency the speaker is being asked to play. Don't set your receiver to 6 Ohms. Leave it at 8. When you set it to 6 Ohms, all it does is limit the output so you get less power and probably compressed sound. Which receiver do you own? Maurice Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted February 18, 2005 Share Posted February 18, 2005 The impedance of all speakers varies with frequency. The Klipsch speakers are usually 8 ohms compatible which means that they tend to be easy to drive due to their high sensitivity, but may have a lower actual impedance. True 8 ohm nominal speakers should average 8 ohms. Low impedance loads require a very good amp if you do not want frequency response and bass to suffer. One way to ease the load on an amp is to run speakers as "small" so that a subwoofer does most of the work below the crossover frequency. Bass frequencies require the most power, so shareing the load with a powered subwoofer helps. I have run my RF-7s off of a 130 watt receiver. The results were good. A separate amp that can drive the low impedance has definitely been much better. Many folks prefer 200 watt solid state amps for the reference towers. The tube amp folks use much lower wattage with sucess. Bill PS: I would leave the receiver at 8 ohms unless it gets too hot or shuts down. Always ventilate a receiver. B Quote Link to comment Share on other sites More sharing options...
leok Posted February 18, 2005 Share Posted February 18, 2005 I prefer the sound of both my tube amps using the 4 instead of 8 Ohm taps. Using a lower output impedance from the amp, you're almost certain to reduce impact of the speaker impedance variation on amp gain. Also, you don't really loose power. You trade increased current capability for peak voltage capability. You actually improve the amp's capability to deliver full power to the low impedance points. Leo Quote Link to comment Share on other sites More sharing options...
organ Posted February 18, 2005 Share Posted February 18, 2005 ---------------- On 2/18/2005 12:11:33 PM leok wrote: I prefer the sound of both my tube amps using the 4 instead of 8 Ohm taps. Using a lower output impedance from the amp, you're almost certain to reduce impact of the speaker impedance variation on amp gain. Also, you don't really loose power. You trade increased current capability for peak voltage capability. You actually improve the amp's capability to deliver full power to the low impedance points. Leo ---------------- Hi Leo, Did you get increased dynamics/slam with the lower impedance tap? I own the RF-35 but I'm not sure how low the impedance dip is. But I'm guessing it does get close to 4 Ohms. I'm using the 8 Ohms tap right now and I'm wondering what the 4 Ohms sounds like. I haven't tried it because I need to get under the hood and solder the leads. Maybe I'm just too lazy . Maurice Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted February 18, 2005 Share Posted February 18, 2005 ---------------- On 2/18/2005 1:18:09 PM organ wrote: ---------------- On 2/18/2005 12:11:33 PM leok wrote: I prefer the sound of both my tube amps using the 4 instead of 8 Ohm taps. Using a lower output impedance from the amp, you're almost certain to reduce impact of the speaker impedance variation on amp gain. Also, you don't really loose power. You trade increased current capability for peak voltage capability. You actually improve the amp's capability to deliver full power to the low impedance points. Leo ---------------- Hi Leo, Did you get increased dynamics/slam with the lower impedance tap? I own the RF-35 but I'm not sure how low the impedance dip is. But I'm guessing it does get close to 4 Ohms. I'm using the 8 Ohms tap right now and I'm wondering what the 4 Ohms sounds like. I haven't tried it because I need to get under the hood and solder the leads. Maybe I'm just too lazy . Maurice ---------------- Maurice, in my experience, you do get increased slam/control with the woofers by changing to the 4 ohm tap. I now run the 4 ohm tap with my RF-7s/Mark III combination, and it helps control the woofers. The best thing, however, is always trial and error. Whereas my Mark IIIs like the 4 ohm tap, my Marantz 8B seems to drive my Belles overall - a bit better on the 8 ohm tap. So, it is somewhat speaker and tube amp dependent. However, as a generality, yes, it is worth trying to run your RF-35s off of your 4 ohm tap. Gib: Owned the RB-75s before and currently own a similar receiver. Very nice speakers, but not all that demanding. Leave your Yammie on 8. Carl. Quote Link to comment Share on other sites More sharing options...
leok Posted February 18, 2005 Share Posted February 18, 2005 Smoother frequency response, clearer. Not sure about "slam." My interpretation of "slam" is added dynamic punch that comes from distortion, and that's certainly not what is meant here, so I can't comment on slam. It's easy to try and won't hurt anything. I really don't think loss of power is an issue at all, even though gain will have to be set a bit higher for similar volumes. I believe there is more power where the speaker really needs it. Leo Quote Link to comment Share on other sites More sharing options...
laurenc319 Posted February 18, 2005 Share Posted February 18, 2005 hi, My Fortes sound a bit better using the 4 ohm taps of a EICO HF-81 integrated amp. So it pays to experiment and see what works for you Larry Quote Link to comment Share on other sites More sharing options...
scotbuck Posted February 18, 2005 Share Posted February 18, 2005 ---------------- On 2/18/2005 12:11:33 PM leok wrote: I prefer the sound of both my tube amps using the 4 instead of 8 Ohm taps. Using a lower output impedance from the amp, you're almost certain to reduce impact of the speaker impedance variation on amp gain. Also, you don't really loose power. You trade increased current capability for peak voltage capability. You actually improve the amp's capability to deliver full power to the low impedance points. Leo ---------------- Greetings, I've found this to be true of all my tube amps. Asking for less current seems to make the overall sound a bit sweeter on top and a bit punchier on bottom. Not quite as loud overall, more dynamic and lively. The amp doesn't sound like it's working as hard, and therefore has a bit more in reserve for the dynamics. I've experienced this with Lowther and Tannoy speakers in addition to Klipsch. Take care, Scott Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted February 18, 2005 Share Posted February 18, 2005 I've got a Mac 2125 (120 watts) pushing my RF-7s. Do you all recommend that I go to 6 or 4 ohms, or leave at 8? Any adverse effects on either amp or speaker from changing? Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 18, 2005 Share Posted February 18, 2005 When my Khorns were connected to either my EICO HF-81 or my Scott 296, they sounded best overall on the 4 ohm terminals. However, my VRD's are a different story, the 8 ohm terminals yield the best overall sound with my Khorns. Quote Link to comment Share on other sites More sharing options...
gibby214 Posted February 18, 2005 Author Share Posted February 18, 2005 I've got the same question as Bill. Is there any harm done to reciever or speakers when changing to 6 Ohm? I suppose surrounds get the Ohm change also, I use RB25's and RC35 rear. I've got a Yamaha RXV 1400 reciever (2004 model, 110w x 7, $800 retail) Just trying to get the most out of my system. Oh yea I'm jealous of you RF7 owners. I owned my RB 75's for a year before hearing a set of floorstanders. My dealer is a 3 hr drive and didn't have any to demo the 3 times I've been there. Looking for that bone rattling power, but who isn't. Sounds like most tubes like 4 ohm Quote Link to comment Share on other sites More sharing options...
organ Posted February 19, 2005 Share Posted February 19, 2005 Carl and Leo, Thanks a lot for the response. I just turned off the amp and will solder the 4 ohms tap when it cools down. Can't wait to hear how the 35's sound. Maurice Quote Link to comment Share on other sites More sharing options...
leok Posted February 19, 2005 Share Posted February 19, 2005 BillH2121, I'd go for the 4 Ohm. There is no risk to anything. I've been thinking about speaker mfg impedance ratings since an 8 Ohm rating on a speaker with dips to or below 4 Ohms is not a way to encourage users to hear the best out of the speaker. It may simply be marketing. People are comfortable with an 8 Ohm rating. Also, the efficiency rating at 1 Watt / 4 Ohms would be less .. again, marketing. Speaker manufacturers are beginning to do efficiency ratings at 2.84V (which would be 1W into 8 Ohms or 2W into 4 Ohms). I guess either method makes a 4 Ohm speaker appear more efficient than it really is. Anyway, the impedance rating of a speaker is not a good guideline for which tap to use n a tube amp .. I prefer to go by the minimum impedance of the speaker. Leo Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted February 19, 2005 Share Posted February 19, 2005 Thanks Leo - I'll give it a try today. Quote Link to comment Share on other sites More sharing options...
organ Posted February 19, 2005 Share Posted February 19, 2005 Hey guys, I changed taps last night and got a really nice improvement. I got to listen for almost an hour at lower volumes. I was only expecting to hear improvement only in bass but was surprised to hear an overall improvement. Weird eh? Like you guys said, the amp has better control of the woofers and it seems to be digging lower too. The mids sounds cleaner with better dynamics/micro dynamics. Can't wait to try it out loud. Maurice Quote Link to comment Share on other sites More sharing options...
gibby214 Posted February 19, 2005 Author Share Posted February 19, 2005 Any other comments on Ohm settings using a regular reciever.. good for sound, bad for components etc.. Gib Quote Link to comment Share on other sites More sharing options...
doctorcilantro Posted February 19, 2005 Share Posted February 19, 2005 Interesting, my friend has been telling me to try this for a while with my RF-35's. ORGAN - congrats. I will give it a whirl tomorrow. I just had a surprise delivery of some Quicksilver Mini-Mites today. Didn't expect them till Monday, man that was nice, but I was trying to get some homework done : D No preamp yet so I hokked the Denon cdp into the QS's ......my god. SO loud but so clear, I really am stunned. I picked up these amps for 575 shipped and they look & sound brand new. Would bi-wiring pose as any kind of variable when considering going to 4ohms??? dazed & amused, Dr. C Quote Link to comment Share on other sites More sharing options...
leok Posted February 20, 2005 Share Posted February 20, 2005 No issue with bi-wiring. I'm assuming you're still using 1 amp for high and low on a single speaker, just 2 sets of wires for each speaker. Using 2 amps per channel, one for high and one for low, sending a full range output from each amp, letting the high-pass and low-pass crossover sections reject what isn't used may be an issue for several reasons and I wouldn't recommend it. Leo Quote Link to comment Share on other sites More sharing options...
Colin Posted February 20, 2005 Share Posted February 20, 2005 when speakers dip down into the low 2 or 4 ohm range, usually becuase of the woofer impedance, I have found that the 4 or 6-ohm taps tighen up the mid-bass without any loss of volume, the nominal rating is intentionally misleading to the majority of cunsumers who don't care or don't know - all speakers and subs should publish not just their frequency response, but also their impedance curves certainly try it, with tube amps somebody notice an small improvement, with s-s amps, many people do not... oh, and keep us posted! Quote Link to comment Share on other sites More sharing options...
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