Why separates?

Hi Rick,

You're opening a big can of worms, but I will simply give you on my opinion and what it did for my dedicated 7.2 room (3300cu/ft).

I orignially had Klipsch towers in my room, and was happy with my Onkyo 805 given the very high efficiency of the speakers. Then I inherited a pair of 4ohm Vienna Grands from a friend of mine who didn't want them anymore.

It all depends on what kinds of speakers you have and what your listening habits are. Some people like the idea of having the electronics (pre-amp) just handle the switching/processing. You're also able to perform upgrades in the future of just your pre-amp and leave your amps in place. External amps also hold their value VERY WELL in the re-sale market. The main problem is alot of receivers can't deliver the necessary power to all channels at the same time. Moving to the XPA-5, I was able to get more headroom and a very distinct improvement in vocals etc. There wasn't any placebo going on here. Had people over who heard a before/after.

I purchased an Emotiva XPA-5 (300W into 4ohm). and am using my Onkyo 805for pre-amp duty and my rear surrounds. I was blown away (to say the least) on what the XPA-5 did for my room. Being a movie guy, all effects were more pronounced, soundstage opened a huge deal, and all of my 2ch listening was improved. This was a $1000 investment. (and when combined with the new speakers) provided me with a jaw dropping wow factor that I never had before.

Again, this is just my non-technical opinion about how it sounded to me. Feel free to PM me with any other questions.

The only thing an amp is going to change is the power level, and it's up to you to decide if you would use more power. It is not going to open up the soundstage or do any of that bupkis.

+1

I have also done back to back listening sessions between an Onkyo 805 powering my speakers and a B&K Reference 200.3 amp (200 wpc x 3) powering my speakers and there was no audible difference whatsoever (in movies or music) once the two sources were level matched.

Are they both Class D amps ?

None of the amps or receivers mentioned so far in this thread are class D amps.

Should not matter any way - a watt is a watt.

What are they then ?

Class A/B

class AB. A separate amp will give you the ability to turn up your movies without distortion. Lots of the people that are hearing differences could quite possibly be running out of steam with their receivers and getting distortion. The added amp will allow you to turn it up louder, distortion free.

Everyone is different.

I'll tell you exactly what I noticed when taking the 805 off of the duty of driving my entire dedicated 7.2 system.

- A more immersive soundstage during playback of content.

-During movies I heard effects that I hadn't noticed before. Specifically, my surrounds woke up big time, in a very pronounced way. Impact of glass breaking, grenade explosions with dirt flying across the screen, you name it. This could be indicitive of the 805 not having enough juice to drive all channels in my 3300cu ft room at the SPL levels that I listen at. But if you know the 805, you know it has a killer amp section.

-Dialogue was sometimes felt "distant" and soft during various pieces of content. I noticed a pretty substantial improvement in movie dialogue. I have a second row of seating that is about 19ft back from the main speakers.

The problem that I AM experiencing right now is a trebley, kinda harsh tone issue that presents itself on the higher frequency range, and I can't for the life of me determine where it's coming from. Viennas are fairly laid back speakers. I spent hours with REW, and friends who are intimately familiar with Vienna Grand Beethovens, switching out the XPA-5 back to just Onkyo and we can't figure it out. Tried manually dialing down some of the EQ ranges, with marginal improvement.

Would it be fixed if I put a Marantz AV7005 or Integra DHC 80.3 in there instead? who knows. Room treatments, maybe.... already treating first and second reflection points though..

If the amp is doing its job correctly it will only amplify the pre-amp section no colorization of the sound.
If you have non efficient speakers playing fairly loud with low impedance you might need an external amp.
If you run your speakers full range you might need an amp.
If you want to play it loud enough for your neighbors to enjoy your selection you might need an amp.
If you bought a flagship cross the low frequency over at 80Hz you probably will not hear any difference by adding an external amp.

I originally started with a Marantz SR5400 receiver with 90watts rms per channel. I had it connected to all of my speakers. The only ones I will discuss at this time are the mains, Paradigm Studio 100 V3. They sounded quite good when powered with the Marantz. Later, I had purchased a Rotel RMB-1075 5-ch amplifier with 120watts rms per channel and a Rotel RB-1090 2-ch amplifier with 400watts rms per channel.

After purchasing the Rotels, I had connected the Paradigms to the RMB-1075. Basically it sounded about the same as when connected to just the Marantz. 30watts really won't gain you much additional volume. Sound stage and all that stuff was same as well.

However, I did notice a difference when the Paradigms were connected to the RM-1090, which is how I currently have them configured. The main difference is I can reach a louder maximum volume. I don't have measurements to show the difference. There wasn't really any change in the sound stage and all that stuff, but you could kinda say the sound was perceived to be more full. I think this is only due to being more dB's, especially on the lower frequencies. As mentioned earlier, at matched sound levels, all three methods of amplification sounded the same.

Basically what I am saying is that separate amplifiers can allow for the opportunity of more power to the speakers and independent processor updatability, but the sound stage and stuff still comes from the device doing the processing and your speaker placement. I do plan to upgrade to a separate processor and omit the receiver. My reason for doing this is so I only need to upgrade processors in the future. The amplifiers should continue to do their thing no matter what processor I have in the future.

Keep in mind, if you look at a speaker's sensitivity rating, for instance 88dB/watt at 1 meter, this means you might get roughly 88dB of sound at 1 meter of distance with only 1 watt of power. Also, you gain roughly 3dB of volume with every doubling of the power. 3dB more is typically known as just noticeable difference in volume, and 10dB more is twice as loud. You can google this stuff to learn more, but one such link is: Power and dB

So at:
1/8w gives ~79dB
0.25w gives ~82dB
0.5w gives ~85dB
1w gives ~88dB
2w --> ~91dB
4w --> ~94dB
8w --> ~97dB
16w --> ~100dB
32w --> ~103dB
64w --> ~106dB
128w --> ~109dB
256w --> ~112dB
512w --> ~115dB

All numbers are approximate and only there to show the relative relationship between amplifier power ratings and SPL. Also, most of us sit farther than 1meter from our speakers, so these numbers are less (as shown in the link I posted above) in your listening position.

Hope this helps. Also, everyone, feel free to correct me if you see an error.

It all depends on the impedance load of the speakers you're driving. You can not just generalize everything. Lets take the Klipsch RF7ii for example, you would think with an 8 ohm 101db speaker that any $200 AVR is more then suitable to push this speaker. The actuality is this speaker dips below 4 ohms from 100-200hz, this is basically putting the same demands on your AVR as the upper region of a subwoofer. That mid bass punch that you're expecting with a pair of 10" woofers is now being completely fluffed over by the AVR's inability to handle that. It doesn't help that the RF7 is actually only 96db also

If your speakers have a fairly smooth 8ohm load, then yes an amp is pointless. Don't let the spec sheet fool you though, most will benefit from solid power into the complex impedance loads of your average multi-driver speaker.

So you guys are telling me that when I get my Butler 5150 150 watts x 5 .... I will hear no difference from my Onkyo 5009 that is 145 watts x 7 ...... Ok Bet I will tell the truth when I get it in two weeks ... So even though it's a Solid State - Tube Hybrid ... There will be no difference ! Ok in Two weeks we will see ! I hope you guys are wrong lol lol

HomeTheater1010, do you have a method of measuring your system's response? If you do, I would be interested in seeing if there are any quantitative differences in the two amplification methods. Try to do some true A/B testing with the help of a friend to do the switching, and you do the listening. It will work pretty well, if he tries to switch them randomly, then you listen to the same track or movie clip repeatedly. It will help if he doesn't say anything except OK (meaning something has or has not been switched).

I only suggest this because of a recent experience I had with a friend who had a $200 power cable he wanted me to try and I swapped it and he claimed he could hear a difference. It turned out that after he left, I ran through my receiver and discovered that the sub was not even turned ON. So, just him knowing that I changed the cable, the placebo effect took place and knew he could hear a difference.

If you paid the amount shown on Butler's site, I sure hope you notice a difference. However if after the A/B testing you don't hear a difference, I would send it back.

Good luck, and I look forward to hearing your results.

There's two types of separates in my way of thinking (and ignoring a 2 channel music setup, which is another discussion.)

1) You augment a receiver with external amps
2) You have a processor, with no amps, and add amps

1) Tends to be cheaper. Whether you need to add amps to a receiver depends on many variables which I am too tired to cover in detail - desired SPL, room size, speakers, acoustics, etc.

I feel a good quality receiver, which might set you back more than a typical mid range receiver can drive some setups very well. Budget receivers usually lack preouts, making them a non option in either case. Some mid range receivers might benefit from external amps, but of course they need pre outs.

Option (2) requires external amps. Some people feel the processor will sound better simply because it lacks amps...of course that would be more interesting with some proof

Don't let the graphs fool you, either. These are exactly the impedance load graphs salesmen use to show you that the $$$$ speaker cable they want to sell you will sound better.

The reality is that in the average home theater set up, at the average volume people listen to, with the average media, these variations do not normally produce an audible effect, just like those $$$$ speaker cables do not produce an audible effect.

That's why blind tests show people can't tell a difference between amps working within spec.

Ok you guys got it .... Blind test and with a reading from my tester .ill also test voltage to each speaker to show if its a true 150 watts RMS

Ok, so what's the update? Did you receive the amp? Do any testing? What's the verdict?