Why amps?

[GranteedEV]

I'm not sure I can wrap my brain around this logic- not saying its not right, it just doesn't make sense to me.. Care to elaborate a bit more? What do you mean "biased towards efficiently delivering watts" ????

phone battery dyin, will get back to you later.

 

[Nuance AH]

Thanks, Pyrrho - I figured I might have missed something.

 

[avnetguy]

Are five speakers playing the exact same signal, and is that signal even summing up in perfect phase at the listening position?

Very good point. Would the above be true in either (or both) of the following real world situations?

1> Listening to multi-channel music using the AVR's DSP to output a stereo source to 5.1.
2> During a common explosive action flick scene, Michael Bay kind deal.

I guess the above would assume that a single point AVR configuration would be used and the sound processsing output for the multi-channel music would be set for 100% for all speakers.

Steve

 

[PENG]

Steve, you must have calculated for a 1m distance. At an 8ft distance that would yield 98db.

Now I guess you made an assumption too, i.e. open field with no room reinforcement effect. In a room, it would vary depending on the acoustic condition/configuration but you would likely get more. In my room, doubling the distance would not result in 6 dB loss, more like 3 dB, may be 4 at the most.

 

[PENG]

8 feet is over 2.4 meters, and the sound is coming from multiple speakers, not just one (though one does not simply add the numbers in dB from the different channels), so your numbers are off from the start. But your conclusion, that most people do not need external amplifiers, is correct. External amplifiers are needed if the speakers are a difficult load (low impedance, keeping in mind that "nominal" impedance ratings do not tell the impedance at every frequency) that the receiver cannot handle, or if one needs more power than the receiver can put out (which will depend on the speakers, how loud one likes it, etc.).

Sometimes, when people use external amplifiers, they are actually degrading their sound, as being an external amplifier does not mean that it is better in every way from something built in (see this for a popular example, though in this case it depends on how the amplifier is used, and obviously the particular receiver under consideration).


To directly answer your question, for most people, buying external amplifiers would be wasting money. Though certainly not in all cases. People who have difficult to drive speakers, or who listen very loud (and who don't have high sensitivity speakers) require more power than most people. People with larger rooms than most require more power than other people with the same speakers in a smaller room (that is acoustically otherwise similar).

Also, your idea of keeping with "mid-level" receivers is a good one, as the budget models can involve too many sacrifices in quality (as well as features). I think most people don't need to spend more than about $600 for a receiver. And if they need more power, typically it would be best to still buy the $600 receiver (with preamp outputs for all channels) and buy external power amplifiers instead of a more powerful receiver, for two reasons. First, one can get more power with an external amplifier, and second, when new features come out that they need or want, they just replace the $600 receiver and keep the external amplifiers.

I used to use a receiver that retailed for about $600, but because I wanted more features (and the old one was too old to have things like HDMI), I replaced it with a receiver that retails for about $1700. Unless I engage a feature that affects the sound, it sounds the same as the $600 receiver. Now, it could matter in some cases, as the more expensive one can put out about twice the power of the old one, but the old one could drive my speakers to levels I found painful with crystal clarity, so the extra power is useless in my case. (The only reason I bought such a high model receiver was because I got it at a great discount as a discontinued model from an authorized dealer; I paid about 1/4 of its retail price. On the other hand, I have thousands invested in my speakers, because there one will hear differences. If sound quality is what you want, put your money in your speakers.)

We can keep telling people this until cows comes home but there will still be no shortage of people telling others how their amps are making "night and day" kind of differences and that even at low volume the difference is huge etc. May be by low volume they meant 'just reference level'??

There is no cure for Placebo!! I read about at least one guy (another forum) who replaced his MCH Bryston and AV7005 with a 4311 and never looked back. I myself had also tried using my ex-4308 (similar output to the 4311) with and without external amp(s) and heard no difference so yes I guess I wasted my money too. I should have saved those money on amps and spent it on getting better speakers but like many other people I found it hard to resist the temptation. It is much easier to go buy more watts than to try and audition even just 6 pairs of speakers and pick out the real winner. There was a time I wanted to save up for a McIntosh separate system but I eventually woke up, fortunately, and decided to just go with a nice picture on the wall behind my average looking amps.

 

[avnetguy]

We can keep telling people this until cows comes home but there will still be no shortage of people telling others how their amps are making "night and day" kind of differences and that even at low volume the difference is huge etc. May be by low volume they meant 'just reference level'??

One thing that normally comes up is headroom when people look at buying more power and I'm just trying to understand is more headroom needed above what a mid-level AVR provides?

If most mid-level AVR's are capable of outputing 100w or so and say 50-70w is all that is needed for a typical setup to reach short term 105db+ with low distortion .... well I'm just not seeing the need. I'm not saying there isn't some conditions that require more power just not so with a typical setup. Then again, maybe there is something and I need to run out to get an amp for myself to see what bigger power does!

Steve

 

[PENG]

One thing that normally comes up is headroom when people look at buying more power and I'm just trying to understand is more headroom needed above what a mid-level AVR provides?

If most mid-level AVR's are capable of outputing 100w or so and say 50-70w is all that is needed for a typical setup to reach short term 105db+ with low distortion .... well I'm just not seeing the need. I'm not saying there isn't some conditions that require more power just not so with a typical setup. Then again, maybe there is something and I need to run out to get an amp for myself to see what bigger power does!

Steve

I think you are right in many cases. As mentioned before, under certain conditions such as low impedance dips, large phase angle between current and voltage, high spl requirements, large room, mch stereo mode, types of music etc., could eat up the limited head room offered by some mid level avr.

 

[Pyrrho]

We can keep telling people this until cows comes home but there will still be no shortage of people telling others how their amps are making "night and day" kind of differences and that even at low volume the difference is huge etc. May be by low volume they meant 'just reference level'??

There is no cure for Placebo!! I read about at least one guy (another forum) who replaced his MCH Bryston and AV7005 with a 4311 and never looked back. I myself had also tried using my ex-4308 (similar output to the 4311) with and without external amp(s) and heard no difference so yes I guess I wasted my money too. I should have saved those money on amps and spent it on getting better speakers but like many other people I found it hard to resist the temptation. It is much easier to go buy more watts than to try and audition even just 6 pairs of speakers and pick out the real winner. There was a time I wanted to save up for a McIntosh separate system but I eventually woke up, fortunately, and decided to just go with a nice picture on the wall behind my average looking amps.

It isn't just the placebo effect (though that is a real problem as well). With a more expensive receiver or separate power amps, one can point to some number of watts that the thing is capable of putting out compared with another (or rated distortion or some other number), or some set of features, so it is easy to point to a real difference (even if that real difference makes no audible difference in practice), but it is much harder to point to a difference in quality between different speakers. I think that is a selling point for many people, that they can find something that is better about the one thing that is easy to understand, whereas it is difficult to give a precise and clear answer to the question of why one particular speaker sounds so much better than another that has similar specifications.

Most people spend too much of their budget on electronics, and not enough on speakers, if actual sound quality is the goal. A high end receiver mostly gives one features and extra power, not something else. With speakers, since they are all of them grossly flawed in distortion and frequency response (compared with decent amplifiers and digital sources), the differences between them are often quite audible. And it gets even more complicated than that, as the dispersion of the sound from different speakers can differ greatly as well, which must also be considered when trying to figure out (if one tries to figure out) why the one sounds so much different from another. It is much easier to understand that a very powerful amplifier can put out more power than a lesser one, or can deal with lower impedances, than to understand what it is about one speaker that makes it sound more real than another speaker with similar specifications.

And, of course, I can pick out a "better" amplifier online without listening to it, but I can't do that so well with speakers. The best sounding speakers I have ever owned do not have great looking specifications considering their price tag. And although I know far more than most people about audio gear, I am quite at a loss to give any real explanation for why those speakers sound better than the others that I have owned. I expect that there are those who can give some sort of explanation, but I would very much like to know it myself. (My subjective impression is that there is less distortion of some kind, though that is no substitute for measuring something and knowing about it.) The reviews I have read do not deal with the objective performance in enough detail to give me the answer to my question.

And, incidentally, I would be happier if some other speakers that I own sounded better, as those are more trouble to deal with than any other speaker I have ever owned. But the sound of them has a je ne sais quoi that the others lack. They almost make it seem like I raise Ella Fitzgerald from the dead and bring her into my living room to sing to me. Of course, my subjective impression, even though it coincides with that of many others, does nothing to explain what it is that is different about these speakers from the others that I have owned.

I think that being able to understand why one amplifier is better than another helps sell it, whereas not understanding why one speaker is better than another makes it less attractive to people and they don't bother listening to them to find out how different they really are. To keep us from going into too many different directions, comparing only the frequency response, with typical decent amplifiers, they will all be audibly perfectly flat when operated within their design limits, but with two speakers, even if rated with the same frequency response plus or minus 3dB, that is enough variation to be audible, as one might be up 3dB where the other is down 3dB, and the one might have a smoother curve that gently slopes down at each frequency extreme, whereas the other one might go up and down those 3dB many times between its frequency extremes. But just saying they are both 40-20kHz +/-3dB does not give that sort of information. And then of course there is distortion of various types, which typically is not specified with speakers, and on those rare occasions when something is given, it is not likely specified for different volumes, which, of course, is important, as different amounts of movement of the drivers are likely to result in different amounts of distortion (with higher volumes likely resulting in more distortion in most cases).

 

[derrickdj1]

Why use external amp

First, when considering on the need for an external amp, one needs to ask what are my goalsl, what am I using now and what is my budget. Amps can be needed for multi-channel systems that do not employ Class D amp. Non Class D avr's loose power when driving multiple channels even with efficient speakers like Klipsch. Modern audio and video sources have a larger dynamic range compared to years ago so the response of the HT has to be more dynamic. Amp also have large heat sink and transformer that keep the amp from becoming stressed as fast as avr's, which leads to lower distortion. A good amp can last for 20+ years, avr's are good for 5-8 years due to technology improvement. Amps in general are most stable with their power output over a greater frequency range.

With all that said the easiest way to improve the SQ of a system is with better speakers. Amps also deliver more current at the output stage in the chain of amplification compared to a similar watt avr. This results in better driver control and dynamic control of the speaker. Even Class D ICE amp have noticeable power drops when pushed hard. I would like to see a review of class D amp vs standard class A/B power amps. A lot of Power amp makers are offer a class D external amp due to the potential of the amp to delivery much more power than traditional avr's or amps. Getting into separate can be expensive, but buying and avr with pre-outs can make adding an amp more affordable. In general, when adding better speakers to a system, the speaker rating for RMS and peak power will increase.

 

[derrickdj1]

Why use external amps

The improved sound from a properly matched system to the amp is definitely not a placebo effect. The sound is fuller and has more clarity. The placebo effect may be due to improperly matched components. Some people also use tube amps due to the warmer sound. Tube produce distortion in the second harmonics that are synergistic with the music leading to their perceived warmer sound. Amps are for people that like the flexibility that they provide to their system and they also delivery on the performance side. A Ford Escort and a Lexus will both get you across town, but it is in enjoying the drive that adds pleasure to the trip.