Klipsch Reference Owners???

[MatrixDweller]

Thanks for that goon. That's why I love this forum.

I sold my 2808ci a week ago. I got an amazing deal on it through a friend who works at a retailer so I managed to sell it for a nice profit. I'll be using that money to get something a little better. I was tossing around the 3808ci for a while and have pretty much settled on the Onkyo 875. I'm without a receiver right now and getting edgy. I won't be getting a new one for another couple weeks because the wife had found a way to spend my other savings .

[justin.kerr]

I think it would be more accurate to say that the Klipsch RF-83 speakers are sensitive, but also difficult to drive. My old Yamaha receiver would get hot and shut off driving them at moderate levels, and even now my Cinenova will shut off, due to thermal overload protection kicking in. The low impedance dips, down to 2.8 ohms, get things heated up.

[thxgoon]

From what I can see there are two concerns in this thread. 1 is that the speakers are very sensitive thereby requiring less power for a given output. The other is that they have a dip in impedance meaning that they are hard to drive. From what I gather based on the posts on this thread is that the latter overcomes the sensitivity resulting in a speaker that is actually harder on an amp than a higher impedance less sensitive one. Lets look at three senarios where each speaker is being ran at the frequency where it's impedance is lowest as I think we can all agree that that's when it's hardest on the amp and all have the same output

Speaker A (RF-83's)
100db Sensitivity - 2.8 Ohms - 1 Watt

Speaker B (same impedance but normal sensitivity)
90db Sensitivity - 2.8 ohms - 10 Watts

Speaker C (normal sensitivity and 'easy' impedance)
90db Sensitivity - 5.6 ohms - 5 Watts

So even if the Klipsch are running into low impedance territory it is relatively insignificant compared to the advantage of its sensitivity. From Ohm's laws a 10db advantage in sensitivity means 10X less power while half of the impedance only means 2X as much power. Speaker C is still 5X harder to drive than the RF-83's.

Ohm's laws:

P=RI^2
and
P=IV
and V=IR

I'll leave it to you to apply the math as it's too much work to type it all out.

Justin - I don't doubt that you have run your amps into protection. It is not because you have Klipsch, it's a good thing you have Klipsch.

[bmplockmonster]

math doesn't lie

[a1161979]

Doesnt this assume that the amplifiers power supply can deliver power into those low loads? Presuming an amplifier with a well designed protection curcuit then surely speaker C will place less strain on the amplifier? Also when you say harder you mean wattage however in reality its the current requirement that constitues the strain on the amplifier

[glaufman]

Kinda true..... absolutely....... sort of.......
In real power terms, a high current requirement equals a high power requirement, assuming voltage is kept constant. In the case of an amplifier feeding a speaker, and I hope someone more more knowledgable than myself can confirm or deny this for me, I suspect we're dealing with a significant amount of reactive power... that is, in laymen's terms, energy that is sourced by the amplifier but not used by the speakers, which the amplifier then has to sink... you can see the amplifier's ability to do this (if your speaker cables are sufficiently large) by running a quick test: turn the speakers switch on your amp to off, and lightly tap the cone of your woofer... the sound you hear is effectively the mechanical resonance of the woofer... now turn the speaker switch back to on with no signal input, and tap the cone the same way, you should hear almost no sound, as the amplifier's error correction circuitry is nulling out the signal the speakers are sending back to the amplifier... at any rate...
This reactive power increases the effective load on your amplifier... further, Ohm's laws can easily be maniuplated to show that the most effective power transfer occurs when the impedance of the source equals the impedance of the load... the greater the difference between these impedances, the less efficient your amp will be working...
As a big fan of Klipsch products, I'm surprised to hear they dip down below 3 Ohms... perhaps someone could elaborate on the good/bad nature of this in speaker design...
Have you tried a different set of high quality speakers connected to this amp? just out of curiosity, and what about your airflow around the amp? Is it in a cramped cabinet?
Generally, if you have a speaker impedance switch on your amp, it's safer for the amp to set it to 4 Ohms even if your running 8Ohm speakers...

[jakewash]

When you set an amp to the 4ohm setting it might be safer for the amp but it will put the amp into a low output mode so you will not get full power out of it, limiting the volume level. I would leave the amp in 8ohm mode, regardless of the speaker and if it shuts down due to the volume level while playing. it is time to get a better amp.

Yamaha is known for redesigning their receivers from the ground up year to year, so one year a particular receiver will handle a 4 ohm load very well, while the next year it's replacement won't.

I have run 3, 8 ohm speakers in parallel from my Denon 1804 and now my 3808, I was testing out center channels and had the SPL at 75-80 for over an hour with out any problems.

If your amp is shutting down due to heat issues, try setting up a fan to blow on it while using it to see if it helps, if it does then you know it is a heat issue, if the amp still shuts down the there is another problem.

[glaufman]

jakewash wrote:

When you set an amp to the 4ohm setting it might be safer for the amp but it will put the amp into a low output mode so you will not get full power out of it, limiting the volume level. I would leave the amp in 8ohm mode, regardless of the speaker and if it shuts down due to the volume level while playing. it is time to get a better amp.

Keep in mind, full volume levels of many amps are way too loud for most of our listening spaces... I find I usually run my amp at about 30% of full scale on the dial... I find it's sometimes beneficial to play with the gains of various sections to maintain the same general sound levels while making sure all frequencies are being properly excited...

At any rate, it's been a while, but I'm pretty sure that when I did the taste test on my own system with switching between 4 and 8 ohms on the receiver (8 ohm speakers) there was no sound difference...

[acommonsoul]

What do you guys think of the RW-12D? I just picked one up the other day for about $500 on clearance. From what I have heard it sounds pretty good, but I would like to hear other people's opinions.

[MatrixDweller]

I have a RW12d and like it. It can move a lot of air when it needs to. It doesn't go as low or as accurate as most SVS' but at $500 I think you got a really good sub. I wouldn't say they were worth the full retail price however. I managed to get the IR codes programmed into my harmony and it works, but the sensor is on the rear panel so I have to try and bounce the signal off the wall for it to work from my seated position. The front display doesn't glow when the remote is used either so there's no way of telling if it actually received the signal worked.

[acommonsoul]

Thanks for the response...I was originally planning on purchasing the SVS psb-10, but I thought the deal on the Klipsch was too good to pass up.

[dtaylor]

I own the RF-63 and matched it with the RC-64 and i am very happy with the refrence line, it's powered with the Denon 2808ci.