Thanks a lot
obobskivich
for your detailed reply! It helps a lot but I still have a few questions about what you've said in order to clarify a few things.
With numbers - no problem!
You're right that if Windows crashes, the volume can go sky high but it's really not common anymore with Windows 10 but I still really wouldn't want that to happen since I sit at less than 2M from the speakers.
Honestly I've probably had this happen 2 or 3 times since Vista came out, but that's 2 or 3 times too many if you're relying on the soundcard to control the volume into a power amplifier or active speakers, at least in my view. Basically because I can't trust it to work 100% of the time and fail safe, I'd rather put another device in the mix that I can trust to work 100% of the time. But that's me. There are probably many people who have happily gone along with the computer as a preamp in recent years and never had a problem, and I've done it "in a pinch" in the past as well (even prior to Vista), but for a long term solution it's just not something I'd personally do. Especially with headphones or speakers that you're very close to.
1- Honnestly I've never understood why pre-amps were so damn expensive for no reason. I mean, I already have the best possible audio coming from a computer's PCI-E soundcard and its software can already do pretty much anything I'd want and anyway it's rarely a good idea to mess around too much with special effects and it's always best to keep the EQ as neutral as possible so I would never need the special sound effects which alter the music, from those 1000-3000$ pre-amp or want to pay for 90% of inputs/outputs that I would never be using at all. I guess it is only good when you have a hometheater that isn't connected to an HTPC so you have no choice than having a pre-amp since you don't have a computer with a high-end soundcard inside?
I think "expensive for no good reason" is a big part of it. It's a niche product and they can (and do) charge what they want. They also don't sell enough of them to mass produce them on a scale that will force the price down. As far as the whole EQ/"effects" thing - it really depends on the system. Generally having EQ or other DSP correction for speakers (e.g. time alignment, bass management, channel leveling, etc) in a room is not a bad idea, but as always let your ears decide if its really helping anything. I agree with using a soft touch either way, but personally I'd like to have the options available. That said, ZxR has most of this already built-in (as do many other devices that have stand-alone multi-ch outputs, like higher end DVD or Blu-ray players), so again you really don't need a mega-buck stand-alone home theater processor (but THAT said, those mega-buck stand-alone home theater processors take a massive depreciation hit on the used market, and can be a surprisingly affordable alternative to a "cheap" AV receiver or hi-fi multi-channel preamp (e.g. Parasound P7)).
2- From what I've read, if I use the optical output from my computer's soundcard, I would be bypassing the high-end DAC from it and all of it's features which I've paid for, only to be using instead the DAC from the receiver which is definitely gonna be worse, or from a 10 years old pre-amp that prolly won't be any better. Something that can make your soundcard more expensive is the opamps it uses for each channels, but then again if you go the digital route, you'll be bypassing them right? That's why I've always been using analog/rca instead so it uses my 200$ soundcard instead of the crap inside my consumer's receiver.
The digital out will bypass the DAC and analog sections in the soundcard, yes. It will not bypass the soundcard's processing though (e.g. you will still get SBX, you will still get all of its multi-channel controls, etc). There are some historic examples (from around when Windows Vista first came out) where digital out could defeat some processing features, but that's generally been fixed with newer drivers, software, and soundcards (e.g. the ZxR) so there's nothing to worry about there. As far as DAC quality, the ZxR certainly has a good quality DAC, but so do many home theater components, especially if you're going with yesteryear's mega-buck SSP or similar - I wouldn't be so quick to dismiss a piece of gear simply because its old or doesn't have contemporary buzzword compliance. Let your ears decide how it sounds for you - personally one of the best sounding DACs I've ever heard is in a 15+ year old Technics surround sound processor, and I will freely admit it has no "right" to sound as good as it does, but it's what I like. That isn't to say ZxR is "worse" or "better" - honestly I'd regard both as good (and qualify that differences between DACs are generally fairly small, even when comparing designs that are substantially different).
3- I don't understand also people who pay a premium for a receiver or a pre-amp to have the latest HDMI and other gimmick, as can't you just connect anything that's video related... to the TV directly and then use your (pre-amp/power-amp/receiver/stereo-integrated-amp) ONLY for audio?! It rarely evolve in the audio departement while for video stuff it keep changing every 2-3 years such as you get a 2000$ piece of equipement with HDMI 1.4 + 3D 1080P then it's good as useless since we're now with HDMI 2.0 + 4K, if you see what I mean.
That's how THX used to suggest configuring home theater, but in recent years HDMI has more or less created a closed ecosystem thanks to HDCP and other licencing requirements: new players/devices are generally required to be HDMI-only unless the manufacturer wants to pay a penalty or deals in very low volume. And as HDCP evolves, the requirements to support it change, so you get people pushed into new equipment. It's certainly more cyclical than in years past where you were just dealing with baseband or Y/C video and analog audio.
4- I've never heard before of the category (Stereo Integrated Amplifier). I've tryed to check the Yamaha you've shown me as an example and I'm still trying to understand for who this thing could be useful? If you go the seperate way, it would be a pre-amp + power-amp, but if you go all-in-one it's gonna be a receiver so what is the stereo amplifier? Is it the same thing as a receiver (pre-amp + amplifier) but there's NOTHING for video I/O and it is only stereo? I never heard about a "Multi-Channel Integrated Amplfier" so are those stereo thingy, a thing from the past that we won't be seeing anymore?
Integrated amplifiers are a pre-amplifier and a power amplifier in one box. They exist as both stereo and multi-channel varieties. The multi-channel ones have never been very common, but did enjoy a minor period of "popularity" (if you can call it that; I'd say more like "they were a fad for a short while") in the mid 90s. Since they generally don't have any significant digital processing, they're analog-in/analog-out and many of them are really excellent sounding. The DSP-E492 is itself a bit of an oddity beyond that, as its designed to add 3 additional (analog) channels of preamp and amplification to an existing 2ch system (e.g. an integrated amplifier, or a receiver) - by modern home theater standards its a dinosaur, but if you're plugging it into the ZxR you've got the "brains" in the computer, and it can provide the "brawn" to drive the speakers (beyond the main right/left, that is).
5- Me too I've never understood why in the high-end departement, it often seems as you pay a lot more, for a lot less features while it should be the exact opposite. It makes no sense that it gets cheaper to buy an high-end 2CH amp for my front's Q900 speakers, with a cheaper 3CH amp for my Center/Rear's KEF Egg speakers... than just getting 1 5CH amp. The specs of the 5CH amp also always seem to be of lesser quality than a less expensive 2CH amp so I guess I should be going quality instead of quantity?
Absolutely quality over quantity. As far as 5ch amps in general - they get very big and very complicated fairly quickly, because while you may only be doing 100W or 150W per channel, the innards have to do that five times over, and that's where you run into complexity. And that drives the prices up. And you're also dealing with niche products.
PART #2 of my other audio questions:
6- If I'm connected directly from my soundcard to my amplifier, does the amp always send at maximum output "100W for example" or if my computer's volume is at 50% then my amp will only be outputting 50W since it will also be turned down to 50% and have a lower power consumption?
Yes and no. The amplifier doesn't "see" any volume level (unless its a switching amplifier where it alters its supply and/or output rails relative to the input - examples are Class D, Class H, BASH, etc; these are pretty atypical for full-range audio amplifiers (Class D *is* getting more popular though), but not at all uncommon for subwoofers - their big advantage is efficiency). You're controlling the volume by making the signal at the amplifier's input bigger or smaller, and then the amplifier does what it does: amplifies that signal. So if the ZxR is set to 50%, its its a smaller signal than 100%, and thus the output is quieter. As far as a correlation between the ZxR or Windows' volume control (as a percentage) and power output, you'd need measurement equipment to establish it. It certainly is not linear, and even at 100% you will not be getting 100% power output unless the source material is 0 dBFS (e.g. a brickwall of noise). Generally speaking with most speakers you're probably only using a few watts (if that) for typical program material - so why do you want the bigger amplifier? Dynamics. If you only need 1W to get to a nice listening level (say your speakers are 90 dB/W/m (which is pretty average) you will have a comfortable-borderline-loud listening level at around .5-1W at 2M), you still need more power for when the signal gets louder internally (e.g. an explosion in a movie, that's recorded at a higher level than dialog, and meant to be louder in the playback). So if you have a 100W amplifier, you get 20 dB of headroom over your comfortable-borderline-loud listening level (which is basically Dolby/THX spec) and the thing doesn't go into clipping when something goes "bang" on-screen.
All of this applies to headphones as well, in principle, but the numbers are much smaller and its MUCH easier and cheaper to get LOTS (relatively speaking) of power.
How to know how much what I'm sending to my speakers, as I've seen in the specs of an amp, that it was having a THD of 0.03% at half a watt, but 0.05% at 1W/Channel O_o
Not surprising that THD increases as power input increases - that's pretty typical. Generally you won't be sending all that much power into your speakers, unless they're very insensitive.
7- Someone told me to never plug a speaker's which maximum wattage is higher, than 3 time the amount of the amp's per channel. For example if I'd plug my Q900's 200W speaker on a 50W/Ch amp, it would be higher than 150W so it would damage the amp, but What I've always been on a cheap receiver's with only 50W per channel and I've never damaged anything, so is it just myths?
That "rule" sounds fishy. The "maximum wattage" on the speaker is likely its maximum power handling, as in you risk damaging the speaker (physically) if you send in more power than that (and depending on exactly how that specification was arrived at, it may be damaged if you send it that much power continuously for any significant length of time too). So you don't want to send it that much power. But you also don't want the amplifier to be too small, where it runs into clipping (which can kill speakers) when it should be getting somewhat louder. However you won't ever draw more power than you "need" (e.g. if your desired output level only requires 2W of power for a given speaker, that's all you need and all the speaker will consume), so as long as your performance target is within appropriate operating range for the amplifier, and that number isn't bigger than the speaker's power handling, you're AOK. As far as "how do we determine that performance target" - you need sensitivity numbers for the speaker, and a rough idea of how far away you are from the speaker, and how loud you want things. Or be lazy and use an online calculator: http://myhometheater.homestead.com/splcalculator.html (it explains what you need to plug in for it to figure things out).
If we use the 90 dB/W/m example above, and say you sit 2M away, and you want 80 dB listening level (because that's honestly fairly loud; over 85 dB gets into hearing damage territory (http://www.gcaudio.com/resources/howtos/loudness.html)), and you have a 50W amplifier, you will have no problems (plugging all of that into the calculator yields a peak output of 104.8 dB, which is super-duper loud; if we're lazy and round that up to 105 dB and say our goal is 85 dB so we're just subtracting 20 dB, you need around .5W of power).
8- What is the difference if I plug my 200W speakers into an amp of 125W/Ch instead of the same model but with 200W/Ch? Do I need to use the later one in order to reach the full potential of details from my speakers at any volume, or will there be absolutely no sound quality difference, but only volume output? I'm sitting so close that I could care less about how loud a system play, I just want to get 100% of my speaker's potential and I wouldn't want to pay a lot more for the (Rotel RB-1582 MKII) if the (Rotel RB-1552 MKII) would sound just as good.
You're asking two questions here:
1) Which amplifier will make my speaker sound best?
and
2) How much power do I actually need? (could also be re-written as: How much difference will 200W/ch make vs 125W/ch)?
The first question is subjective and hard to answer - ultimately you'll have to let your ears decide what amplifier pairs best with your speakers and other gear and best suits your ears and taste. Generally a good amplifier from any decent manufacturer (Rotel counts) is a good place to start, but it may not be your exact cup of tea.
The second question is a lot easier: no there won't be a big difference between 125W and 200W (its less than 3dB) and you will be driving neither amplifier at or near that output power for normal program material with normal speakers, especially if you sit close. However if the 200W amplifier is "better" (per question #1) you could be forgiven for believing the extra power is whats helping (and generally higher power amplifiers are higher quality/higher end, at least that's how many manufacturers arrange their product lines, so there is some logic to this; this shouldn't mean you need to buy the biggest amplifier you can find though).
9- At the opposite, what happens if I plug 100W speakers into an amp that's doing 200W/Ch, am I gonna damage anything?
In practice, probably not. In theory, it could damage them by feeding them more power than they're designed or rated to handle.
10- I've read that it required 2X more wattage each time you add +3dB as everytime you add +3dB, the sound gets 2x louder, is it true or am I wrong? Because if so, it means that my less efficient KHT-3005 speaker would require at the same 8Ohm, twice more power to play as loud as the Q900 since there is a 3dB difference?
KEF Q900 (91dB Sens + 114dB Max + 200W)
KHT-3005 (88dB Sens + 108dB Max + 100W)
+3 dB requires 2x power, however +3 dB is not "twice as loud" - that's 10 dB (which requires 10x power; dB is on a log scale). Yes the other channel will require more power to hit the same output level based on those specs. However 3 dB isn't a huge difference, and also consider placement - if you're using the 3005s as surrounds they may very well be closer to your seated position, so you need less power there (as you move closer you have less distance loss so your power requirements get smaller).
11- Do you have an idea why all Rotel's multi-channel amp are of 116dB, even the more powerful stereo RB-1582, while the RB-1552 have a Signal-to-Noise ratio of 120dB? Actualy, is it just worthless specs as you could measure the difference in a lab, but there's no way that a human ear could notice the difference since simply nobody anyway listen at such high levels that would damage the earing? I've also read that the Dynamic Range of a CD was of only 90dB and even just 70dB for a Vinyl, and nobody's complaining about how "noisy" it is.
Yes, no, and all of the above could be true here. Are they worthless or potentially exaggerate specs? Sure. Is it a significant difference, even if true/taken at face value? Probably not. Does it indicate that Rotel is trying to tell us their stereo amplifiers are designed to be higher quality than their multi-channel amplifiers? Maybe. The CD/vinyl example is a great example of where over-reliance on specs doesn't always tell the complete picture.
12- Does the amp automaticly recognize a 4Ohm vs 8Ohm speaker? Do I need to wire my speakers in a special way behind my amp to wether set it to 4 or 8 Ohm?
For contemporary solid state amplifiers it shouldn't be a problem as long as its compatible with both 4 and 8 ohm loads (it will say in the manual or on the amplifier itself what its minimum impedance loading is). For older tube amplifiers there are generally separate transformer taps for different impedance loadings, which are also explained in their respective documentation. When in doubt, read the manual.
13- Does the (Damping Factor) have a high influence on sound quality? Strangely, all multi-channel amp hover around 150-180 while most stereo amp go higher between 450-800 which is far more, and I've read that the higher the better as you'd get more control over the membrane of the speakers for high impact bass, explosions and stuff like that.
This is a giant can of worms. I'll just leave you with some links and let you explore on your own:
http://www.roger-russell.com/wire/wire.htm#damping
http://sound.westhost.com/impedanc.htm
http://www.butleraudio.com/damping1.php (note that this isn't advertising on Butler's part - they're reprinting stuff from JBL for convenience)
In the simplest sense, damping factor is supposed to show the relationship between the amplifier's internal or output impedance and the load impedance. The problems start with it as a loose spec in a manual or PR copy when you start asking questions of it, like: how does that impedance change with frequency? What did the speaker design assume about source impedance? What about the interaction of wiring? How much NFB is being used to achieve this really high number, and what impacts may that have? etc
Generally I'd ignore it as a loose spec unless the manufacturer is providing appropriate qualifiers (e.g. they're telling you at what frequency into what kind of load etc) and then with this data point in hand, you're off to the land of never-ending subjective debate about "how does it sound and what sounds better?"
14- If I'm thinking about all of this, since I'm being in stereo 2.0 90% of the time, I never listen to any movies on my computer and I play games much less often than I used to, and I could just as well use my (Beyerdynamic T90) headphone to play games and use the virtual surround of my soundcard, then I'd be better off spending my money into a high-end modern stereo amp, and only get either a receiver or a cheap/old 2-3CH amp for my surround speakers for the rare time I play games, instead of getting a 15 years old 5CH amp that's gonna be pretty much the same price of the best Rotel's 2CH amp from 2015?
As I said before, I wouldn't put so much weight on "its new and therefore better" when it comes to this kind of stuff. That said, I'm a fan of 2 channel, and if you're primarily using stereo, I'd probably just get your favorite pair of speakers, a decent integrated amplifier or stereo receiver (or comparable separates) and be done with it. Depending on what you buy, it may also drive the T90 (a lot of IAs and receivers have headphone jacks on them; some headphone amps also can drive speakers). If you wanted to add surround on top of that in a simple way, there's where the DSP-E492 comes into play, since it would just stack onto your stereo component (as long as it has pre/main couplers). It'd give you a common volume control setup external to software and let you add 5.1 (or 4.1, or 4.0, or whatever surround sound configuration you wanted) when desired, but retain a primarily 2 channel system the rest of the time. There are many other ways to accomplish that (there's *tons* of gear out there), and by no means am I saying the E492 is the best/only/most correct/most righteous/etc way to do this, its just an example of a real-world product to consider and maybe stir you thinking about other ways to wire up what you want. If you went with the older SSP route it likely would have a stereo mode, so you could just send it a signal and let it figure out what the output map needs to be based on A) your taste at the time and B) what you have hooked up to it (e.g. the Technics I mentioned above fits into this).
Generally I'd be a fan of used gear, because of the depreciation hit a lot of this stuff takes from new, and because if you're primarily dealing with a PC you don't need HDMI/MHL/whatever connectivity as you're likely dealing with analog or S/PDIF digital, which was very standardized for a long time so there's *lots* of gear out there to consider.
Thanks a million time if you can get to answer those many questions, as I'm pretty sure I wouldn't have any other after hehe
No problem.
