Still struggling to understand the ins and outs re: input sensitivity

[ryanosaur]

Its been a few days since my eyes were opened to pre-amp output voltage and input sensitivity on the power amp. In that time I've scoured forums and articles including everything I could find here, but am still struggling.

Some background: Recently acquired Marantz sr6012. Using old home theater in a box Onkyo speakers until i can resolve the speaker and amplifier question. Leaning very strongly towards monitor audio silver 500s, C350 + surrounds. Want to use an Amp to maximize the front 3, and my marantz for the surrounds. Room size is exceptional at >8000'3 due to large open floor plan, though my listening area is only about 1/4-1/3 of this area. (Thus, large speakers that I want to maximize for active music listening and occasional home theater and social entertaining.)

After reading, perhaps, too much, I have seen written:

"just get it, plug it in, and try it... you can always return it if it doesn't work right."
".825v(or 8.25mVa) input sensitivity is low"
".825 input sensitivity is high"
That my 1.4 v pre-out is too high for the outlaw 2200 monoblock (.825mva) and too low for the Emotiva XPA DR 3 (2.1v input sensitivity). Which, depending on the author, directly opposes the 2nd or 3rd point listed above.

It would seem the safest assumption on my part is the Emotiva XPA3 (with input sensitivity @ 1.5v, 275w all channls driven, and a potential peak of 550w, per Emo's tech guy)

I don't think I'm being daft, here. Though I'm freely willing to admit to confusion, as this will be my first power amplifier purchase. I'd like to get it right. I greatly appreciate any direct help, as well as pointers to help learn more about high end gear in general. It almost seems like I need to add electrician to my previous experience as professional musician and acoustics aficionado.

All that out of the way. Please:
What is the low-down on matching pre-amp to power amp? Which is high-sensitivity? How much wiggle room is there between pre-out voltage and said sensitivity? (.1v is ok, but .6v over/.7v under (or vice versa depending on which of the above points is correct)?) Or phrased differently, at which points over or under powered should I expect to potentially start clipping my signals from the pre-amp or to the speakers?

Thank you to all who wish to help, and to all who've helped get me this far. I look forward to your posts!

Best,
R

 

[lovinthehd]

Did you try this article? https://www.audioholics.com/audio-amplifier/amplifier-voltage-gain

 

[ryanosaur]

Yes. Several times. To say I grok it would be a fib, though i do get some of it on an instinctual level. Some of the math is over my head. This is, however, the article which caused me to choose this forum over others as I realized the potential for learning here.

 

[lovinthehd]

Basically you simply need enough pre-out to drive a given amp. If the sensitivity of the amp is a much higher voltage than your pre-out, then you'll have problems maximizing the amp. Getting accurate information on pre-out voltage range for your pre-amp section can be hard to determine, tho, as many just quote a nominal level.

 

[ryanosaur]

Yes. Seen that mentioned a lot. Marantz claims 1.4v max pre-amp output voltage for all current d&m holding products... but the article u referenced earlier showed an older marantz: "Meanwhile in the distant past of 2010, a [marantzsr6004] was able to deliver 7 volts pk-pk (2.49Vrms) from its pre-outs."

But that still doesn't help me understand what I'm missing from the basic questions I asked above. I'm being given crumbs and trying to piece together a cake. I wish I could afford to blow out a couple amps or speakers in the learning process. I also wish I was a better mathematician and that my HS physics class in electricity wasn't almost 30 yrs behind me. (I can dream, ya?)

So what is enough? is my 1.4v output too much of the outlaw monoblock and not enough for the XPA-Dr-3? or is it the other way around? 'Cos I've seen both discussed by people claiming they know what they're talking about.

Thank you!

 

[lovinthehd]

Why do you need an external amp at all would be where I'd start. I doubt the max is 1.4V output on all the Marantz models....what's your source for that? I have Crown XLS amps with 1.4V sensitivity and have no issues with my Denons or Onkyo avrs driving them. I wouldn't worry about too much pre-output.

 

[ryanosaur]

1.4v pre-out? That was verbal from marantz tech, along with the "all d&m holding products" as well. Do I take that for gospel? No. Again: tryin to make cake from crumbs.
Why an external amp? Going back to my original post, I have my listening area in the greatroom of our home, with an open floor plan yielding 8312.5'3. I am an avid and active listener. The leftover speakers I am using as a stop gap work passably well for passive listening. Within 5 minutes of starting Le Sacre du Printemps, my speakers might as well be farting. *shrug When I go for pop, no biggy, gets loud, doesn't sound distorted, but they don't sound real. So real speakers, real power. If I wanted a frat party, I'd go for Klipsch:98dB sensitivity, 150w rms, not really the sound I want, though. I'm going to go listen to MA Silvers in a few weeks, but without hearing them in practice, everything I've heard about them is pretty much what I'm looking for (in theory). Large room, large speakers: Silver 500: 250w rms, 90dB sensitivity. Yes I can run them on 150w, but that still requires an amp, as my research tells me the Marantz SR6012 is only going to output around 70wpc, all channels driven (and rated 110w per 2 channels driven). No, i'm not worried about turning it up an extra decibel, but the headroom on an amp to hit those dynamics is whats important to me. And you can believe I'm taking Igor with me when I listen to those 500's! Especially cos I cant get the Boston Symphony orchestra in my room to play for me, either.

You say you wouldn't worry about too much pre-out juice. OK. I have to ask again, why? One person... actually several sources, have said that the input sensitivity is the max you want to give an amp. This is why I'm asking?

Again, my thanks. I want to learn how this works and why.

 

[everettT]

Most of D&M products can output up to 4v. The 1.4 isn't the maximum. No need for concern with their products.

 

[TLS Guy]

Your problem is that you are confusing the output for given sensitivity and headroom.

Headroom is a really good thing, and not enough of it is a bad thing.

The next concept you need to understand is gain structure.

There is a problem to an extent as standard line input have never been really defined, but there is a convention of sorts.

Now the line input for an RCA connection is generally in the range of 1 to 1.4 volts. Now the output voltage of a preamp is specified like wise. An RCA out is generally in the 1 to 1.5 volt range. So the output voltage is specified at the specified input voltage.

Now this is where headroom comes in. If those numbers were maximum you would have a lousy rig. Music is very dynamic. When a sound seems twice as loud as another, then the power and therefore voltage to produce the power has to be not double but increase ten fold. As this is a log and not a linear scale. The db scale is log to the base 10.

This is where headroom is important. This is just about never specified and should be. This is what really separates the men from the boys so to speak. Good gear has lots of headroom, cheap and nasty gear not much as a rule. So headroom is important through out the electronic chain. So we expect the line in to handle the 1 to 1.4 volts. However we don't want it to overload if that is exceeded. The more it can be exceeded the batter. So if it can take 7 volts so much the better, if 14 even better still. Same with the output, the more headroom the better. If it can manage 7 or 14 so much the better.

When I measured my Marantz pre pros they could output 14 volts before clipping on the scope. So excellent headroom. The late Peter Walker, friend and mentor to me, always realized that for the proper reproduction and enjoyment of music headroom was one of the most important aspects to the design of audio equipment. He used to design enormous head room into his Quad Electroacoustics products. Now this spec. is virtually never present and should be. In other words the lousy dumb manufacturers should not only specify what voltage at the input gives what voltage at the output, but also how much voltage at both input and output before clipping. That is usually only specified for power amps, but should be for input and preamp voltage gain stages also.

Lastly gain structure, you really do want to feed all inputs of gear at a structure that gets as close to matching the voltage that delivers the specified output. In other words if the spec is 1.2 out for 1.2 in then that will give you optimal signal over noise, which is the S/N ration. If you load the device way below then you will have to turn up the volume more and get more noise with signal. However do not forget that the db code is log, so you have a lot of leeway. That is a round about way to say you are worrying about this far too much, and what really matters which is headroom that you don't know unless you, or someone else has measured it. In general I have found though that if it is cheap it has low headroom and if more classy up market gear, it has more headroom. However that is not hard and fast by any means.

 

[highfigh]

One person... actually several sources, have said that the input sensitivity is the max you want to give an amp. This is why I'm asking?

Look at gain as a ratio which, inside of the power amp, is usually fixed. It receives voltage at the input and higher voltage is measured at the output with a specified load. Based on the ratio, it will need a certain voltage at the input to develop that specific output voltage and this is called sensitivity but the marketing departments like to use Power when they state an amplifier's output because it's a larger number and that's seen as 'more impressive' by many people. Any other voltage at the input will result in a different output voltage. This is used by many to 'match' a preamp with a power amp- if the preamp only outputs .7V, a power amp that has 1.2V sensitivity will be perceived as 'under-powered', but it's really the preamp that was a bad match in the system. Conversely, that power amp's input might be overloaded if a preamp with maximum output of 4V or more is used AND that maximum output reaches the power amp. This is where headroom comes in but as TLS wrote, it's not hard and fast because some power amps can actually work properly when higher voltage is present at the input- is this higher output voltage a continuous measurement/rating, or its peak output? That makes a big difference. Some power amps have input level controls and even some tech support people can't answer the question of "Is this level control affecting the amplifier's gain or just the input voltage?".

 

[PENG]

What is the low-down on matching pre-amp to power amp? Which is high-sensitivity? How much wiggle room is there between pre-out voltage and said sensitivity? (.1v is ok, but .6v over/.7v under (or vice versa depending on which of the above points is correct)?) Or phrased differently, at which points over or under powered should I expect to potentially start clipping my signals from the pre-amp or to the speakers?

First of all, let's make sure you are not confused between the terms "pre-out" voltage and "sensitivity".

Input sensitivity of a power amplifier in V (volts): This is the voltage at the input that will cause the amplifier to reach full rated power.

Use your XPA-3 as example, if the specified sensitivity is 1.5 V, 8 ohm load for full power, that means is you apply 1.5 V at its input, you will get 300 W output into an 8 ohm resistive load.

Fact check: I check their numbers with my spreadsheet (calculations) and found that Emotiva's specs of :

• Input Sensitivity (for rated power; 8 Ohm load): 1.5 V.
• Gain: 29 dB.

is not quite correct but one might consider it close enough. To be more accurate, either the sensitivity needs to be about 1.7 V, or the sensitivity has to be about 32.66 dB.

Note: If you want to do the calculations yourself, the formula are in @Steve81's article that HD linked in post#2. Steve is one of the best technical writer I have ever known (electronically). If he wrote it, then I know he researched the topic he wrote about so the contents would be trustworthy to read. This is important because there are many inaccurate/incorrect information on the internet.

Pre-out in V of an AVR, AVP or preamp: This is the voltage available at the AVR, integrated amps, or AVP (pre processors) pre-out terminals to drive external amplifiers. Most people have a good idea what they mean, but no one knows their exact meaning because there appear to be no consistency for this particular spec. Yamaha, D&M, Onkyo, Parasound all seem to specified them differently, such as just the voltage, or with additional vague details.

Examples:

D&M.................................1.2 V (what the heck, rms peak, for rated output, we have to guess/assume)
Rotel.................................1.2 V
Bryston.............................8.0 V RMS with DSP, 10 V RMS Bypass
McIntosh..........................2.5 V, Maximum 6.0 V, 6.5 V for the top MX160
NAD.................................. >4 V for top model, not provided for the lower model T 758
Yamaha...........................1.0 V/470 ohms, Maximum 2.0 V or more (more? give me a break)
Yamaha CX-A5200..........2.0 V/470 ohms, Maximum 4.0 V
Yamaha CX-A5100..........2.0 V/470 ohms, Maximum 4.25 V or more (0.06% THD) - I like this one better
Anthem............................4.2 V RMS, Maximum, <0.1% THD (This is much better, but <0.1% THD, come on..)
Onkyo...............................1.0 V/320 ohms

Based on many measurements I made and articles I read, I would not worry too much about this as long as you stick with the popular brand's upper middle range AVR, AVP or preamps.

Regarding your questions on whether a sensitivity specs is high or low, that's really relative. 0.775 relative to 1.4 is of course HIGH, and vice versa. We are talking about input sensitivity of an amplifier, so the lower the number, the higher the sensitivity, or gain. In other words, a lower number actually means a higher gain, therefore the amplifier is more sensitive to the input voltage.

Matching: If you mean making sue a preamp has high enough voltage to drive a power amp to its rated output with adquate headroom, then I believe the question has been answered already, at least in a generic sense. If you have the specific models in mind, then we can narrow things down for you.

Next question..

 

[ryanosaur]

Wow! Thank you guys. Really.

I've got to do this in bits.

TLS: I'd like to think I had a better grip on the headroom... I awkwardly asked about the "wiggle" room between pre-out voltage and the amps input sensitivity (which I thought to be a hard limiting factor). My understanding from reading all your posts here is that it is not the limiting factor I thought it to be, but it does still play a role. (I will ask clarification in a moment.) Moreover, the actual amount of headroom is not determinable by the values that manufacturers usually give us.
Is there a way that we can infer the headroom available before an amp clips/blows?
***not without the values discussed in your 2nd to last paragraph: source voltage in; the gain, resulting in voltage out; as well as the distortion limits for said voltages (i.e. are you feeding too much in?). All of which needs to be applied across the whole system, not just the power amp.

Did I get that right?

Highfigh: I'm with you... get what your saying. I do see the same question though, inside your post... if we flip the .7v preout and the 1.2v input sensitivity, thus arbitrarily creating a 1.2v preout into a .7v input sensitive amp, is there a risk of overpowering the amp at that small a value of .5v?

Part of the answer I see is that no, assuming the amp has headroom for a stronger signal/higher voltage, knowing that the 1.2v preout signal is only going to be occasional, not constant.

Peng: At this point, definitely straight on the pre-out voltage vs input sensitivity. Not happy that the numbers may or may not mean what they should... but hey, what's a few volts among friends? Thank you for clarifying the high sensitivity part. And matching... I do want to take you up on further discussing this, which brings me back around to that clarification point I mentioned with TLS:

I'm still a little hung up on how to handle the actual numbers of what my marantz's pre-outs can do to, or with, an amp. So from this whole series of posts, we've seen 1.2v, 1.4v, 2.49vrms, 4v, and 7v pk-pk associated with Marantz products pre-amp outputs.
Keeping with the thread, can we please use the amps already discussed in looking at some matching exercises. Please mind, I'm not asking you guys to tell me what I should buy, rather why one works better than another given the Marantz SR6012 AVR is my starting point. My plan is to run these amps to power most likely MA Silver 500's and a C350, both are 8ohm, 90dB sensitivity, with the 500's being rated for 250w, and the C350 for 200w RMS.

Outlaw 2200 monoblock. verbally told ".825mVa, with potential to actually hit 300w rms" but I see on their site: Gain +27dB(1.7v sensitivity) for full output, 200wRMS @8ohms
Emotiva XPA-3: 275w RMS per channel @8 ohms, all channels driven; Gain +29dB, 1.5V sensitivity
Emotiva XPA-DR-3: 450w rms per channel @ 8ohms, all channels driven; Gain +29dB, 2.0v sensitivity
And lets add in for kicks:
Anthem MCA325 225w per channel @8 ohms; gain +29dB, 1.5v sensitivity (no mention if that is for all channels driven).



Again Thank you to ALL!

 

[lovinthehd]

You still don't know what the actual outputs of your avr are without measuring, they're likely to be much higher than you think in any case. I wouldn't worry about using any of the amps you're mentioning.

 

[lovinthehd]

You do realize that even with a doubling of power that's only a 3dB spl gain....

 

[ryanosaur]

Hello. Yes, to both of those posts. (re: your second post, please see #7 above)

If i were more advanced, i would like to learn how to use those instruments. And in a year or two, perhaps I will have the tools and know how to do it.

I'm not the kind of guy to blindly do what i'm told... i'm a question the answers kinda guy. I want to understand better whats going on in my avr, and improve on it to make the music and av experiences sound better in my room. I started learning stuff today that I didn't know yesterday. And it makes me happy. I'm still a month away from speakers and an amplifier, so in the meantime i'm going to learn what i can to make this "starter kit" the best I can. Maybe in a year I buy a new pre/pro that will make the Marantz look like my old Onkyo looked two months ago. And everything I learn and experience now makes that more fun, fulfilling, and worthwhile.

And when I do, i'll need an extra amp for the surrounds.
or maybe new amps and speakers
or maybe.... silliness ensues.

Thanks again to all! Looking forward to what you guys have to say about the hows and whys of my avr interacting with an amp.

If there is a great 3-channel solution for $2500 or less, i'd love to hear about it, too. I didn't see that these Crowns Mr HD and some others have talked about has one.

Cheers!

 

[TLS Guy]

Hello. Yes, to both of those posts. (re: your second post, please see #7 above)

If i were more advanced, i would like to learn how to use those instruments. And in a year or two, perhaps I will have the tools and know how to do it.

I'm not the kind of guy to blindly do what i'm told... i'm a question the answers kinda guy. I want to understand better whats going on in my avr, and improve on it to make the music and av experiences sound better in my room. I started learning stuff today that I didn't know yesterday. And it makes me happy. I'm still a month away from speakers and an amplifier, so in the meantime i'm going to learn what i can to make this "starter kit" the best I can. Maybe in a year I buy a new pre/pro that will make the Marantz look like my old Onkyo looked two months ago. And everything I learn and experience now makes that more fun, fulfilling, and worthwhile.

And when I do, i'll need an extra amp for the surrounds.
or maybe new amps and speakers
or maybe.... silliness ensues.

Thanks again to all! Looking forward to what you guys have to say about the hows and whys of my avr interacting with an amp.

If there is a great 3-channel solution for $2500 or less, i'd love to hear about it, too. I didn't see that these Crowns Mr HD and some others have talked about has one.

Cheers!

Well I think you are over thinking this. You really only have to worry if an output is significantly lower than an input, then you can easily run up against poor signal to noise. If the preamp is higher, there is a thing called a volume control with which you can turn it down. That obviously reduces preamp output. If it is too high you will hear clipping which is very unpleasant distortion, and be forced to turn down the volume unless you are cloth eared.

So just buy your equipment, connect it up and enjoy it. You will quickly find that what you are worrying about is a non problem.

 

[PENG]

Is there a way that we can infer the headroom available before an amp clips/blows?

If you have good ears, one quick way is to turn the volume up one or two clicks at a time until you hear distortions. You can simply play something from your favorite collections that you know has excellent recording quality that you know you cannot hear any distortions at your normal listening levels, then if you start hearing the slightest sign of distortions during the peaks such as a cymbal crash, hold it right there and listen to the same peak(s) a few more time to make sure you find the volume position where you first detected such distortions. Now if the volume is at say, 0 on the relative scale, and you normally listen to this same piece of music at -10, then you have 10 dB of headroom. This is just a quick and easy way, you can do better if you have the proper measuring equipment and/or software. Also, this assumes the bottleneck is the AVR, not your speakers.

Highfigh: I'm with you... get what your saying. I do see the same question though, inside your post... if we flip the .7v preout and the 1.2v input sensitivity, thus arbitrarily creating a 1.2v preout into a .7v input sensitive amp, is there a risk of overpowering the amp at that small a value of .5v?

Part of the answer I see is that no, assuming the amp has headroom for a stronger signal/higher voltage, knowing that the 1.2v preout signal is only going to be occasional, not constant.

Yes, your "Part of the answer...." is correct, but as TLGGuy said, just turn the volume down!! In other words, the volume position will be much lower for the same sound pressure level, if you flip the scenario from feeding a 1.2 V sensitivity power amp with a 0.7 V rated preamp from feeding a 0.7 V rated sensitivity power amp with a 1.2 V rated output preamp. So that is a non issue, but there is a practical limit, though power amps with sensitivity higher (i.e. lower specified voltage, or higher specified dB) are rare.

Not happy that the numbers may or may not mean what they should... but hey, what's a few volts among friends?

You are not alone, I wish they (for AVRs, AVPs and integrated amps) would all specify something like:
Pre-out: 1.2 V RMS, CFP-BW, at <0.01% THD, 3.0 V RMS Maximum at 0.05% THD, >500 ohms.
That's not a lot to ask, and Yamaha did come close to this, but they did it for their AVP CX-A5000 series only.

I'm still a little hung up on how to handle the actual numbers of what my marantz's pre-outs can do to, or with, an amp. So from this whole series of posts, we've seen 1.2v, 1.4v, 2.49vrms, 4v, and 7v pk-pk associated with Marantz products pre-amp outputs.

It did seem to vary between models, and likely the test protocols by different labs could have been different too. Also, keep in mind voltage stated in RMS, peak and peak to peak will obviously be different because:

For sine waves (that's used in those tests),
Peak = RMS X √ 2, or RMS X 1.414
Peak to peak = RMS X 2

If they don't specify RMS, I typically would assume they mean RMS if it is from a reputable manufacturer such as D&M.

Keeping with the thread, can we please use the amps already discussed in looking at some matching exercises. Please mind, I'm not asking you guys to tell me what I should buy, rather why one works better than another given the Marantz SR6012 AVR is my starting point. My plan is to run these amps to power most likely MA Silver 500's and a C350, both are 8ohm, 90dB sensitivity, with the 500's being rated for 250w, and the C350 for 200w RMS.

For those speakers, in a medium size room you will be fine with the SR6012. It depends mainly on how far you sit, if you sit further than 10-12 ft and you listen at or near reference level, the SR6012 won't have much headroom left, may even struggle.

The AVR-X4400H would have given you a little more watts/$ for the same money but regardless, to make a 3 dB difference you need double the power. If you have one or two powerful subwoofers, and set crossovers to 80 or even 100 Hz, you may only need to add 3 X M2200 or a Monolith 3X200 W for the front speakers.

Outlaw 2200 monoblock. verbally told ".825mVa

No idea what .825mVa is, you probably heard him/her wrong.

but I see on their site: Gain +27dB(1.7v sensitivity) for full output, 200wRMS @8ohms

Those specs are typically approximately correct, to a few decimal points. Based on my own calculations and testing, the gain is closer to 27.5 dB or even higher, using the RCA inputs so that's accurate enough I guess. I suspect the M2200 will level match very well with D&M AVRs (including your SR6012). It matches my Denon AVR-X4400H and Marantz AV8801 to within 1 dB on level tests using a spl meter.

Anthem MCA325 225w per channel @8 ohms; gain +29dB, 1.5v sensitivity (no mention if that is for all channels driven).

Good observation, the 225 WPC is for one channel, with two channel it will be close, but with 3 channel driven it probably would drop to 190-200 W, just my educated guess, and that's close enough. If you are in Canada, the MCA 325 would be the one to get. If in the US, I would go for the M2200. I just got mine for $299 when it was on sale. Regular price is $380, but I am sure the $299 sale will be back soon enough.

 

[Johnny2Bad]

For preamp out, discover the output voltage.
For power amp input, discover the input sensitivity.
As long as the output voltage is equal to or greater than the input sensitivity, that means your preamp can drive the power amp to it's rated maximum output. This is a good thing.

If the preamp output voltage is lower than the power amp input sensitivity, it will still drive the power amp but not to maximum level. This may or may not be a problem ... if the power amp's maximum output is more than your speakers / room needs, it may be just fine.

For all inputs to your preamp, the same applies ... you want the output voltage of your source(s) to equal or exceed the input sensitivity of your preamp inputs. Note that different inputs on the preamp may have different input sensitivities. Digital inputs generally are 2V while line level inputs are generally in the 450~750mV range.

In the case of phono (turntable cartridge) inputs, there is rarely an issue as the input sensitivity is typically based on a 5mV cartridge output (moving magnet). A little less is not going to be a problem, a little more, although rare, might be though. The next figure you need to determine is the overload voltage of the preamp's phono input. As long at it's reasonably high, you are good to go. Look for 15mV and higher than that is desirable.

Sometimes people are confused because they see the volume control as akin to a gas pedal in a car. It is more like a brake pedal, if we must use a car analogy. It reduces output, not increases it. So coasting down a hill at 200 mph, it can reduce output (that would be like having too much output voltage than input sensitivity ... too fast or too much still means not safe as long as the brake isn't used, or the volume control is at "max"). But if, in a straight line, the car can't reach 200 mph, turning it "up to 11" won't ever get the car to 200 mph (that would be insufficient output to reach input sensitivity).

Regardless, the position of the volume control is only relative ... in some systems maximum output may be reached at 2:00 (on an analog clock face),in others that same output may not be reached until 5:00, or not at all even then if output voltage is lower than input sensitivity.

If that makes sense, then you should understand that there is no problem using the Outlaw amp and that you cannot achieve maximum output power with the Emotiva amp (so maybe you should choose a lower power version from Emotiva, which will have a lower input sensitivity, because that is directly related to maximum output power).

It is generally considered desirable to have maximum output near the end of the volume control's travel, as this gives the user more control over intermediate levels. People tend to dislike it if the output reaches maximum before "noon" on the volume control, as this makes finer adjustments more difficult. Still, they both work. And if THAT makes sense, then you will understand that you will be using more of the "first half" of the volume control with the Outlaw amp, and might be using all of it with the Emotiva amp.

Input and output impedances play a role in these figures, but as these are well established going back to the telephone system days of 100+ years ago, it's rarely a problem. You could check, though, to insure that the output impedance is 10% or less of the input impedance. If the difference is less than 10%, you will generally need more output power (output voltage) than the "equal or greater" rule of thumb described above.

It will almost never be an issue with Solid State components, as the nature of transistor circuits is very low output impedance. It sometimes can be an issue if mixing a Vacuum State preamp with a Solid State amp.

In the end, I applaud your curiosity and desire to understand these issues, but generally speaking, especially if you don't mix transistor and tube gear, or don't buy European made components (in particular British gear),you will never have issues with output levels and input sensitivities, with the possible exception of very high output power amps (remember input sensitivity and output power are directly related). It's way down on your worry list, to be honest.

 

[ryanosaur]

tee-hee. 8312.5'3 room. 47.5' L x 17.5'W. Ceiling slopes from my listening position 8'H on the right, 12'H on the left. My listening position is ~12' back, leaving the rear wall still 35' behind me. Once I have floorstanding speakers, i will only be ~9' back.

Lovinthehd and TLS: Ya! Totally overthinking it. That was obvious to me yesterday, too. But now I'm starting to understand what is happening rather than just dumbly walking away and buying something because a couple cool cats said it's ok to do so. Teach a man to fish... right? Thank you for joining in and encouraging me to have faith and trust.

Peng: Thank you for the convo! You really helped nudge me along as I was reading some other stuff about amplifiers and speakers, too, including how the tests are run. Re my choice of avr: it was a combination of starry eyes... always like Marantz by reputation, when I realized I could afford to go there, I was stoked. Was about to buy the RS 5012 when the sale hit, and the 6012 was cheaper that what I was gonna spend on the 5012. No brainer there. knowing what I know now, i am in no way sad for my coice. Could I have done better? Ya. But the sound I get through these Onkyo HTIB speakers is great, compared to the old AVR. Do I wish I could have stepped up into the world of true separates. Ya. But now I can save that for a future upgrade. Something like the AV8805, or the new Emotiva RMC-1... Only time will tell! Cheers!

Johnny2: thank you for the late chime in. Nice succinct explanations. Greatly appreciated.

I'm sure I'll be back with more questions between now and the time I buy my amp and speakers.

If anybody else has any other input and insight, please share!

Best to all!

 

[lovinthehd]

The huge room (and especially long) is less about speakers/power than subs at your distance from them. That is a huge room for subs, keep in mind most floorstanders are poor substitutes for subs (IMO). Might check this article out in that respect https://www.audioholics.com/loudspeaker-design/subwoofer-room-size

Another thing you might check out is an spl calculator like this (at least I don't think it's been posted before) http://myhometheater.homestead.com/splcalculator.html

Enjoy the journey....