DYNAMICS

[Sancho Panza]

^^^ with your Reference speakers, right?

[Youthman]

Yes, that was with the RF83. The LaScalas do not have deep bass even with an amp lol

[willland]

Gotcha. Main difference I heard at low volume was bass was full when adding the amp. With just the AVR, I had to crank it up a bit to get the same amount of bass

 

Me too, especially in stereo with mains set to large and no subwoofer engaged.

 

Bill 

[Youthman]

Agreed

[Paducah Home Theater]

Gotcha. Main difference I heard at low volume was bass was full when adding the amp. With just the AVR, I had to crank it up a bit to get the same amount of bass

 

This is a part of what I noticed, and it made no sense to me.  Like I said earlier, my setup could actually get louder.  But, when this one ramped up, it sounded more full.  It just didn't sound the same, and that didn't have anything to do with max volume.  It really wasn't that loud in the store, its just the range was much wider and it sounded more full.  

[Paducah Home Theater]

 

Scrappy, You say the amp sounding better was placebo but then say it sounded much better with an amp at high volume. Can you clarify?

placebo as in at lower volumes one can simply "think" it sounds better. And why shouldn't our brain tell us that when we spend hard earned money on something to add to our system. The ultimate test is a blind comparison where the owner knows nothing about either amp hooked up.

 

 

In this situation it was a blind comparison from my point of view.  I was there to see projectors.  I walked right past the amps and whatnot to view a screen.  I noticed the RF-7ii's playing but didn't pay much attention, I mean that's what I run, nothing special right?  Shortly after was when the waterfall scene came up.  Yeah, something was significantly different.  I had to ask about it and at that point I was shown the amp.  I thought it was just a receiver until that point.  Of course there are lots of other variables, but still, it was pretty significant.  I think they were running full range probably with no sub too though, may not be as big of a difference when running really efficient speakers that are being cut off at 80 hz.  

Edited January 17, 2015 by MetropolisLakeOutfitters

[Scrappydue]

You have to remember how many variables there are though. When you walk in the room you ask about components and they say we have this and this and that amp. But under all that stuff subs could have been hot, speakers set to large, bass eq'ed up on the rf-7ii and rc-64ii. I'm not saying anything about what you heard but there is prolly much more to it than just adding an amp. My opinion only of course. I guess I always wanna try and save people money first and foremost now. So if play with setting and what not first before you spent moolah on an amp.

[CECAA850]

An easy way to envision it.

 

2 hoses both have the same water pressure (wattage).  One is a garden hose and one is a fire hose.  At the same pressure the fire hose puts out a larger volume (current) of water yet they both have the same pressure.

 

If you're putting out a small fire, either hose will do and both will accomplish the same task.  If you need a short burst of water (transient volume) the fire hose will do a better job.

Edited January 17, 2015 by CECAA850

[AaronH]

Great analogy^ !!

[Paducah Home Theater]

You have to remember how many variables there are though. When you walk in the room you ask about components and they say we have this and this and that amp. But under all that stuff subs could have been hot, speakers set to large, bass eq'ed up on the rf-7ii and rc-64ii. I'm not saying anything about what you heard but there is prolly much more to it than just adding an amp. My opinion only of course. I guess I always wanna try and save people money first and foremost now. So if play with setting and what not first before you spent moolah on an amp.

 

I might could understand the fullness but not the dynamics.  Best way I can describe it is on a sliding scale from 1-10.  If i watch something at -25 db, I feel like I am hearing dialogue on maybe a 3 out of 10.  When it ramps up maybe that goes to 6.  When I walked in the store I felt like the dialogue was sitting on a 2 no more than 3.  When the dynamics ramped up I felt like it went to a 7 or 8, then backed down to a 2 or a 3.  Now, I can hit what I can consider a 10, although it may be uncomfortable, but my biggest question is why is their range from high to low significantly more plus much more comfortable once it ramps up.  That's what was shocking.  It was much more fun watching it this way.  I feel like I can go from a 3 to a 6 while theirs goes from a 2 to an 8, on the same movie, same speakers, about the same distance.  Don't get caught up in those exact numbers, that's just the only way I can describe it.  

Edited January 17, 2015 by MetropolisLakeOutfitters

[Scrappydue]

Ok that sounds like something more described as what an amp would do. I would say an amp will make it easier to tolerate loud transient passes cause they are cleaner. For sure I agree with that.

You should go back to the place and ask to hear same setup without amp?

[derrickdj1]

The one thing I learned with my system, adequate power is not only needed for the front three speakers, the surrounds also need it.  Smaller speakers in general are less efficient and have more troubel with demanding loads.

[AaronH]

I want that new marantz pre amp. 7702. That's going to be my next purchase. I know balanced doesn't matter except for long runs but I just want to lol. Let the wasteful spending begin. Oh, and another plus is that I'll get audessey x32

[DaveWJr]

 

I just have a Marantz SR-7009 receiver, supposed to be 125x9 but I doubt that's all channels driven.

 

Correct, spec'd at only 2 channels driven.

 

Not the 7009 here but the 7008.

 

Marantz SR7008 A/V Receiver Test Bench

 

2 channels continuously driven, 8 ohms (watts @ 0.1% / 1.0% THD): 122.5 / 148.0

2 channels continuously driven, 4 ohms (watts at 0.1% / 1.0% THD): 195.4 / 216.8

5 channels continuously driven, 8 ohms (watts at 0.1% / 1.0% THD): 101.2 / 111.5

7 channels continuously driven, 8 ohms (watts at 0.1% / 1.0% THD): 68.8 / 82.2

 

We must assume that since the 7009 is spec'd the same as the 7008 that they would bench very near the same.

 

Bill

 

I have a cliff-notes version of the below at the end.

 

Something to consider, and probably the biggest differentiator between receivers and seperate amplifiers is the abilty to deliver power to different types of loads. Let's take the 200Wx2 into 4 ohms as an example. A resistive load, which is what that bench result you are referencing is absolute cake for an amplifier. Not all 4 ohms, however, are created equal. A 4 ohm resistor has an impedance phase angle of 0deg which is as ideal as it gets. In the bass region, a loudspeaker will tend to creep towards a capacitive load (neg phase angle), and swing from capacitive to inductive (positive) quickly.

 

This is very important because an amplifier HATES driving a capacitance in particular, and second to that is a wildly varying load. You can't drop power across a pure reactance, so if the load of the speaker is more reactive than a resistor (and all loudspeakers are), then that amplifier is going to be to some degree limited in its ability to supply large amounts of current without strain. Were it to do so with reckless abandon, it could either shut down or go into thermal protect. To put it another way, the receiver would have to work harder to deliver what you're asking it to do, so instead...it just doesn't. It dials back the output so that the output is as clean as possible, but not at the power level on the box.

 

The reason is because that impedance phase angle tells you how much power the amplifier is going to have to dissipate, and as far as your amplifier is concerned, a 45deg angle is the absolute worst situation possible. This is where you have maximum resistive and maximum reactive load at the same time. With a 4ohm load at 45deg, your amplifier is dissipating 2x the power than were it a resistor of the same 4ohm impedance. Angles greater (magnitude is implied) than 45deg imply that you're driving more reactance than resistance. In other words, you're turning more power into heat than delivering it to the speaker. These large angles don't occur frequently and when they do, not often in current hungry frequency bands.

 

You take that same 200W into 4 at 0.1% THD from a proper monoblock (frankly most monoblock manufacturers would be ashamed if their 200W amps could only do so at 0.1% THD) or otherwise solidly constructed and designed amplifier, and that 200W into 4 is going to be available when you need it. These strong amplifiers are made to withstand impedance behavior that a receiver is not. So when you hear that dynamic slam from the monoblock setup in the demo room and you can't get that at home, your receiver simply isn't capable of supplying enough current in a short enough time period. More importantly, it's not designed to nor should it be. The receiver knows that were it to have the output devices and power supply of an equivalent 7 or heck 9 channel 150W/ch separate power amp, then it would have the price to reflect that. The receiver then is no longer a cost effective piece of equipment.

 

Long story short: even if you think you have the same power, that's not the entire story. The speaker connected to the receiver is going to determine just how effective it is at transmitting clean power at high levels. Klipsch speakers in particular are very receiver friendly, but that does not mean that your RF7s and RC64 wouldn't enjoy a bespoke amp.

[AaronH]

^THIS

[Paducah Home Theater]

I now have a man crush on Dave W.