Receiver vs. Preamp + amp - Page 2

I said his post is as meaningless as mine unless he provides proof for the potulate he was the first to make. And how are you adding value to the thread and the op? LA is better than Orange County.

What he said.

Ah didn't catch that part of your post. I apologize. Hope I didn't piss you off !

You have to be a moron to think LA is better than the OC! Pure madness! Hahah jk

Curious to see what peaks movies have. That crown amp calc any useful?

LOL. I'd agree. HB is very nice.

Dolby/THX spec having 20 dB available for peaks (we are not getting into a discussion of "instantaneous peaks"); with an assumed baseline average of 85 dB at the listening position, the ability to drive peaks of 105 dB. You spec power for 105 dB. Assuming you want this (I do not, and I've read many other members mention they do not as well - 75 dB seems more popular) as reference level on your system, you have to know speaker sensitivity and distance to figure power needs for 105 dB. Generally it's around 100W in a small-ish room with sensitive-ish speakers (how convenient is that) - we don't really worry about if the receiver can do that ACD, because it never has to. If it can do it into one or two, it's fine. If you need more power, add more power; "audiophile high end" amplifiers are not where I'd start. The first step would be Emotiva or AudioSource; that'll get you to about 500W (which is more than probably any conventional domestic speaker can realistically handle as a continuous program), if that fails, next step: RMX Express! If your needs exceed ~5000W/ch you should probably re-think things...

The bottom line there, and the bottom line here, and the bottom line everywhere is quite simple: two amplifiers operating within their output ranges, not clipping, and properly level-matched (you've heard it before) will be indistinguishable - if you can't pick A apart from B, you cannot preference A over B. Any of the quasi-religious challenges about "open-mindedness" or "trust your ears" are a sad result of the over-aggressive marketing campaigns under-taken in the last ten or so years by "hi-fi" companies; customers shilling customers. If you want to make the argument about recession economics dictating "self lying" or whatever else, that's a slippery slope - prove that it's mediated (I'll tell you right here and now this is NOT going to be an easy study). I think a more fair assessment would be that in the last decade or so, the "high end" types have gotten substantially more aggressive as the market has contracted, and quite a lot has been written critically about them and their wares - think about Monster Cable as a single example.

Regarding the build quality argument:

Irrelevant because we can put all amplifiers inside of a "black box" - if the output is hitting the bar, it doesn't matter what exists inside the "black box." You cannot have it both ways - you cannot summarize all "cheap" component as bad due to their weight, cost, size, etc and then use more minute details to justify more expensive units. You either "black box" all of it, or pick all of it apart (and if you take the second road, you'll find that even some "high end" components perform like hell, and there are a lot of inexpensive devices that do really really well; of course this challenges the "cost = quality" belief system that we all have factually known to define the entire world and everything in it since about the second grade).

If you really want to pick at nits though - the total capacitance even in fancy-pants amplifiers allows for *maybe* a few watts of headroom assuming an (impossible) ACD situation - that's less than a fraction of a dB (which is not audibly different). If you look at true high-power devices, they don't try to sell an ocean of caps as a substitute for more robust output stages and bigger power supplies. I'll let whoever wants to argue with this go off and figure out the math (start by reading this: http://electronics.howstuffworks.com/capacitor2.htm and then probably hop over to Wikipedia (or Wolfram if you're really lazy - like me) to figure the exact values out). Basically, the amplifiers talking about how many million uF they have are blowing lots of smoke - it doesn't increase their output power magically, but it looks great on paper. Toroidal transformers are not universally "better" than conventional models either, but again, they look great in a brochure.

Once we jump beyond that, we can get into the argument about THD and SNR in preamps and receivers, and whine about how having the FM tuner "attracts" noise and other assorted lunacy. We can also hear the arguments about video degradation and all of that due to the "separation" of things (despite many of these components having no RF/EM shielding and not using any sort of shielded connection). And then we can get into benchmarks that demonstrate both solutions to be equally competent.

Dumping equalization and competent video scaling to have a "name brand" on separates will do nothing beneficial for the owner, but it will sure make the salesman a nice margin at the end of the day! If your calculations demand more power due to room size, I'd start with more efficient speakers, and then move into larger amplifiers as needed; generally speaking domestic settings should not require more than a few watts nominally though (and this is for reference level - if you listen quieter then you need less power).

Some links:
http://www.avsforum.com/avs-vb/showthread.php?t=1388399
http://sound.westhost.com/xfmr.htm
http://sound.westhost.com/xfmr2.htm
http://sound.westhost.com/amp-sound.htm
http://www.roger-russell.com/truth/t...goodamplifiers
http://www.hometheaterfocus.com/rece...d-quality.aspx
http://myhometheater.homestead.com/splcalculator.html
http://audiokarma.org/forums/showthread.php?t=58829
http://www.animations.physics.unsw.edu.au/jw/dB.htm
http://trace.wisc.edu/docs/2004-About-dB/
http://www.innerfidelity.com/content/loud-music-sucks
http://www.ccohs.ca/oshanswers/phys_..._auditory.html
Plus there's lots of nifty measurements available from Home Theater for a wide array of (but not all) AV receivers and separate systems. In some cases AV receivers match or even better separate systems costing more. I'm not going to exhaustively link them all though.

I think a lot of people forget to mention, when they say you only need a few watts, that does not include what you need for peak power needs (as mentioned by a poster using an AC Science account.)

I think that could lead to some people thinking they could live with very little power.

Admittedly his scenario involved averages of 8 watts or so, which would be really loud in my home. I listen to movies at about -17 dB below reference as a general rule, which should require little power.

Agreed. I do not intend to imply that a 2W amplifier is necessarily suitable; however an amplifier that can provide between 1 and 10W continuous, and per-channel peaks in the range of 100W-150W, is likely suitable for the vast majority of users. Most competent receivers can do that with no problem.

8W average into a 90 dB/W speaker assuming this is one of those cramped hotel demo rooms, is likely something in excess of 100 dB continuous if we assume it's using modern (musical) material with very little dynamic range. If this is with older material that may have substantially higher dynamic range, I'm just terrified to think about the peak output levels. It's really hard to approximate this without knowing the demands of the material being played back, and asserting that we need hundreds (or thousands, or tens of thousands) of watts "on reserve" to handle playback seems a bit...absurd...for lack of a better word.

Man.....this is simple.Do you have plenty cash to spend? If so buy the best set you can afford comfortably, if not, buy the best set you can afford.Lots of cash get a killer separate set, budget, get a good separate set, money the biggest factor, get a good avr.

Very interesting. I've made this same argument many a times, but just based on my own experience when using an AVR with an external amp... so it is good to hear someone has actually validated this phenomenon with instruments.

The control and dynamics an external amp provides has been obvious to me the first time I hooked up an external amp. Many AVR's, amps, and now pre-amps later, I've yet to hear an AVR by itself come close to matching the impact of an external amp, even at moderate listening levels. A clash of cymbals, for instance, comes on harder and faster. An explosion on a movie soundtrack is simply more explosive. A good external amp is able to reproduce the source material and its peaks and valleys more faithfully, with or without EQ processing.

A good analogy would be to compare an AVR's amps to an economy car, while an external amp with the large robust power supply, capacitors, etc is more like a Corvette. The AVR simply can not match the acceleraton (dynamic peaks) or stopping power or handling (driver control) of a well made external amp.

So if dynamics and control (acceleration and handling) are not important to you or if you have tiny little speakers that can't put the power down anyway, you might as well stick with your AVR (compact economy car).

This example does not provide details, most likely involves a stereo system powering two full range speakers.

Take a 5.1 system with a powered subwoofer and all the receiver has to do is power the requirements for the matrerial over 80hz - with some satellites crossing over maybe even higher, could be at 100 or 120.

The power requirements for the receiver can't be much at all in a normal size room at sound levels that a normal person would find comfortable. Maybe 1 watt? Seems to me it's highly dependent on the assumptions involved.

...which is exactly why I said to use a separate amplifier for the larger caps and toroids... I just didn't take 5 paragraphs to explain the reasoning behind that, as you did. Thanks for adding that in.
You've apparently misinterpreted what I was saying to the OP. My point was that statements like "my AVR has 150 WPC and this stand-alone amp only has 130WPC, so the AVR is 'more powerful'" don't work. An AVR isn't built to have the reserve power that a bigger, heavier amp has, with massive caps and power supplies.
This is why my own system uses Onkyo's flagship AVR, but I still use separate amplifiers for my front 3 speakers.

I'll say that for you, then. Either you need the extra power or an amp is going to do literally nothing for you. Period.

And no, 5-8W averaging music (almost) never will peak at 250W. VERY few things have that kind of dynamic range. As a sales-person, one needs to be extra careful not to appear to be a "golden ear," as it appears to me that AVS is trying to sell us stuff we don't need on information that is almost always false.

I looked up some info on that Peter Smith thing, and this entire PDF is filled with golden ear information. Tube amps, vinyl, and other staples of golden ears. I didn't see anything about the mentioned test, though. If he did report such findings, he was either incorrect or picked some rare music with way above the usual DNR.

Edit: I've checked some songs in Audacity to verify that I am indeed correct. Here are some songs that do NOT have the >30dB of dynamic range that Mike claims, or even CLOSE (these are just pseudo-random songs I selected from my collection - they are NOT hand-chosen to illustrate my point):
-Hook by Blues Traveler
-Far Behind by Candlebox
-Paranoid Android by Radiohead
-Twilight by Electric Light Orchestra
-Losing My Religion by REM

etc.

Wow... someone woke up on the wrong side of the bed this morning!

I want to say, when I wrote a program to compare the highest peak to average ratio, it was 10 to 12 dB for a few classic rock songs ( I did not have the motivation to test more than a few.)

Based on that alone, I think you should expect that you will need more than 10 times the power for music on peaks, than you do for average level.

Modern movies can be assumed to be worse.

What most interests me, is what happens with subwoofers when they run out of power. Maybe it's hard to notice.

From looking at some very old recordings (vinyl restoration) on a DAW, the largest dynamic range I've ever seen is around 40 dB. Most modern music that I've worked with or read about that value is *substantially* lower - I've heard claims of <2 dB for some recordings, but I've never personally witnessed that (maybe heard them on the radio, but who knows).


Seems straight forward enough for me. That'd be 10 dB.


Also straight forward. I think 20 dB is a fair "end of the world" value, but 10 dB is probably closer for the vast majority of content (especially if some sort of compressor is used in the decoder).


Protection mode? Over-heat and melt down? Blow the gasket? etc

Most active subs have protection circuits, and usually more power behind them than they know what to do with. Even if the driver is down there around 80 dB/W it's not using anywhere near the amplifier's total output. The big IB setups (or pro setups) just exaggerate this relationship - 2000-5000W with drivers that are usually pushing 100 dB/W.

Well, I've seen the light. Reciever, coat hanger wire, any ID sub I can afford, really sensitive speakers...that's all a guy needs. Who knew?

Don't forget room treatments, a comfy chair, and a cold beverage.

I like to look at the lab measurements in Home Theater Magazine unfortunately they can not test all but do a good job with the most popular and with some AVR's I can see the need for an external amp as they can not meet their advertised spec under 1% distortion.
The other important test are what amount of wattage will it have in a 4 ohm load along with noise floor .

Or if it's even stable here.

Again, there's lots of receivers that have terrible amplifiers (click the link in my signature for a mess of HT measurements; one of the Sherwood units in there was at 1% THD at something like 3W, the manufacturer claims something like 120W), and that's problematic. But I feel that too often we're drawn to generalize *all* receivers as inferior because of a bad experience with a relatively inexpensive unit.

Here is my potential situation.

Dedicated HT mainly for movies
Denon 4311 to power rear and surrounds
Emotiva for LCR

Would the Denon's room correction work just as well with having the emotiva amp in the mix?

I agree 100 percent with this statement as I did the same.

That sounds like (will sound like ) a fine choice.


Yes.

The microphone that it uses to measure your audio environment hears what has come through the AVR, amp, wiring, speakers and room reflections to your listening position and positions around it (you have to move the mic several times during the calibration). It knows what the test sounds should sound like, hears what they actually sound like and calculates what has to be done to correct for the differences. After the calibration is done, the AVR applies those corrections to all the audio that goes through it. If you make any significant changes to your listening environment (replacing amps, moving furniture, etc), you should run Audyssey's calibration again.

Audyssey isn't perfect, of course. It won't completely eliminate all the problems, but the result usually sounds much better than if it isn't used.

This description is drastically simplified. More details are available on the Audyssey Web site, in the Audyssey threads on this Forum, and in the AVR's manual.