YPAO. And speaker leveling

[JOHN FICKEL]

That is what the underlings will tell you. Klipsch say they are 8 ohm speakers, but they are not. The speakers are significantly below 8 ohms in the power range from 80 to 800 Hz.

This goes to the heart of what is wrong with that Mac auto transformer system. It makes them much more similar to tube amps that do not like wide impedance fluctuations. The auto transformer is similar but not identical to the tapped output transformer on tube amps. The big similarity is that as you increase the output impedance taps, voltage is increased but current is limited. This is fine to drive current into a high impedance load. However you need to optimize current and power demands in the power range. This is always below the transition range where are speaker transitions from half to full space radiator. This is the baffle step. So power delivery will be optimized by setting the auto transformers to match the impedance in the power range.

Now it is a given that less power is required where impedance is high. It is always low impedance areas in the power range you have to optimize for.

This system is nowhere near as good a good output stage that can deliver lots of current into a low impedance load. A good direct coupled output stage bests this auto transformer system any day, particularly driving loads with widely varying impedance and phase angles.

So you are saying Mcintosh is wrong. Ok I'll change to 4 ohm tap and see if I hear any difference. Now my mains are crossed over at 60hz I'm utilizing bass management But I will definitely change to 4 ohm tap. Mcintosh says I'll cut my power 50% ??

 

[JOHN FICKEL]

I agree, leave it on 8 ohms.

Would putting my speakers on the 4 ohm tap cut power by half?

 

[mtrycrafts]

Would putting my speakers on the 4 ohm tap cut power by half?

Not sure but I would certainly follow the makers take on this, period. I think it will limit power though.

 

[mtrycrafts]

Ok. Right now with everything calibrated to 82 db I have to bring the volume up to -20 or so, sometimes higher so bringing everything down to 75db I'll have to turn my speakers down more to get to 75db. I think I'm going to put all my speakers at 0 and see what SPL level reading I'm getting. This Shouldn't be hard lol. My mains are 101 my center is 98 and surrounds are 97db. All very efficient shouldn't have to be much adjusting. I will definitely re-do leveling with my meter not YPAO

From what you said before, you had to turn the trim down to about -4 or so to get to 82 dB. If you set the trims to 0 you'll be getting something close to 90, very loud.
Since receiver makers don't know what sensitive speakers one uses so they just guess and probably around 90 dB spl sensitive is where they set 0. Every one of your speakers will be different trim most likely.

 

[mtrycrafts]

What test disc do you recommend ?

I don't have the latest disc to check all channels but I do have John Eargle's Surround Spectacular on Delos DE3179. Track 42 is left ch, 43, ctr, 44 rt. The three tracks are very precise in level. I emailed John way back when, I think he passed away though, and he stated .1 or .2 dB difference.
The surround ch is track 45. I just disconnect one of the channels then the other to calibrate.
Comparing this to the internal tones on my Onkyo is close enough, a couple of dB maybe.
Reading the manual with the disc, track 31 goes through all 5 channels.
Disc one in this set has some very well recorded music. Google it; Youtube has some tracks on line.

 

[JOHN FICKEL]

Now I was reading on the Klipsch Site and they are saying they heard a Hugh difference in the 4 ohm tap, meaning better. Compared to the 8 ohm tap. With RF-7ii. Also they mentioned that stereofile had run some tests, confirming that the 4 ohm Tap should be used. Weird. I'm going crazy!! Lol

 

[lovinthehd]

Now I was reading on the Klipsch Site and they are saying they heard a Hugh difference in the 4 ohm tap, meaning better. Compared to the 8 ohm tap. With RF-7ii. Also they mentioned that stereofile had run some tests, confirming that the 4 ohm Tap should be used. Weird. I'm going crazy!! Lol

Your avr has 4ohm taps?

 

[mtrycrafts]

Your avr has 4ohm taps?

And I think a 2 Ohm tap as well.

 

[lovinthehd]

And I think a 2 Ohm tap as well.

Don't see it on the back there....thought only tube amps had taps

 

[JOHN FICKEL]

Yea it has 8 4 and 2. All three the Mcintosh has those taps

 

[lovinthehd]

Yea it has 8 4 and 2. All three the Mcintosh has those taps

Sorry, missed the part where you had a mcintosh tube amp....thought it was just the Yamaha avr.

 

[JOHN FICKEL]

Sorry, missed the part where you had a mcintosh tube amp....thought it was just the Yamaha avr.

It's not a tube amp. Is a solid state. MC252. No problem

 

[lovinthehd]

It's not a tube amp. Is a solid state. MC252. No problem

85

 

[lovinthehd]

85

That was going to be d'oh/slaps self

 

[TLS Guy]

Not sure but I would certainly follow the makers take on this, period. I think it will limit power though.

No, unless you talk to a senior engineer you will get the wrong advice. Going to the 4 or two om settings, will double the power available where it counts, and increase the heft of the speaker, by making the current available for BSC.

I find it hard to understand why Mac persist in putting output transformers on a solid state amp. Quite honestly it is long passed the time where you had to limit current from the output devices by matching the load to stop them failing. I could may be see a point in this back in the 70s and early 80s, but it is now pointless and limiting, and was a long time ago.

I know a lot of people lust after Mac amps, but I'm certainly not one of them, far from it.

 

[JOHN FICKEL]

No, unless you talk to a senior engineer you will get the wrong advice. Going to the 4 or two om settings, will double the power available where it counts, and increase the heft of the speaker, by making the current available for BSC.

I find it hard to understand why Mac persist in putting output transformers on a solid state amp. Quite honestly it is long passed the time where you had to limit current from the output devices by matching the load to stop them failing. I could may be see a point in this back in the 70s and early 80s, but it is now pointless and limiting, and was a long time ago.

I know a lot of people lust after Mac amps, but I'm certainly not one of them, far from it.

Ok what is BSC? Forgive my ignorance, So you are saying if I use the 4 ohm tap, I'll "DOUBLE" my power??

 

[Swerd]

Ok what is BSC?

BSC (Baffle Step Compensation) is a circuit, often built into a crossover board, that compensates for the elevated midrange caused by narrower speaker cabinets. Specifically, a BSC circuit lowers the elevation that typically occurs in the roughly 750-1500 Hz range. As it lowers the midrange sound to be even with the bass (below ~750 Hz), it lowers the speaker's overall sensitivity. As a result, a speaker with BSC draws more power from an amp in the frequency range affected by the BSC circuit.

Good layman's explanation: http://www.salksound.com/wp/?p=42

 

[JOHN FICKEL]

BSC (Baffle Step Compensation) is a circuit, often built into a crossover board, that compensates for the elevated midrange caused by most of today's narrower speaker cabinets. Specifically, a BSC circuit lowers the elevation that typically occurs in the roughly 750-1500 Hz range. As it evens the midrange sound with the bass, it lowers the speaker's overall sensitivity.

Good layman's explanation: http://www.salksound.com/wp/?p=42

Ok thank you Would you also recommend 4 ohm tap or leave it on the 8 ohm tap ?

 

[Swerd]

Ok thank you Would you also recommend 4 ohm tap or leave it on the 8 ohm tap ?

Try using the 4 ohm tap, as TLS Guy suggests.

 

[JOHN FICKEL]

Try using the 4 ohm tap, as TLS Guy suggests.

OK I'm just concerned that Mcintosh says, a 8 ohm speaker on the 8ohm tap I'll be getting the 250w , now if that speaker is operating at 4ohm on the 8 ohm tap 400 watts. Now let's switch to the 4 ohm tap, 8 ohm on the 4 ohm tap would be approximately 125 watts, now if my RF-7's Perdominantly operate at 4 ohm 250 watts. Mcintosh strongly suggest 8 ohm taps with all impedance speakers, unless however the amp gets HOT then it's Suggested to go on the 4ohm tap.