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Considering a separate amplifier for (5) 4-OHM bookshelf speakers. Would like to learn some information before I make a purchase. I am Currently driving them with 6/8 OHM rated AVR. The room is 12x12 wondering how I would benefit by adding a separate amp to drive these and if it is even worthwhile for my application. Basically, would I have a noticeable difference? Any recommendations or suggestions would be appreciated.
 

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An external amp could give you more power. You might not need more power. It depends on your current receiver, your listening level, and your speakers.


If you are not familiar with some of the math, you should know that you need double the power for each 3 dB boost in SPL. It does not take a lot of power to get to what I call reasonable listening levels. Say your speakers put out 90 dB with one watt of input 1 meter away. Then say you lose 9 dB over distance to your listening position. Then say you gain 3 dB because of multiple speakers and room interaction (some say 6 dB - I measured 3 dB.) So you only need 1 watt of power for 84 dB. Movies have peaks in excess of 15 dB I believe. For argument's sake, lets say you want to accomodate that. That's 32 watts / channel. That's well within most AVR's capabilities.


Of course, if you like it loud, my logic does not follow.


Some feel externals amps can give you better sound. Something to think about - A guy once offered to give $10,000 to anyone who could tell two amplifiers apart in a blind listening test. No one ever collected. That, along with a few other listening tests that have been tell me amps sound very much alike when they are not clipping. So more power is the only factor I would personally consider. There's many threads on this topic, if you are bored.
 

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Quote:
Originally Posted by jmchea /forum/post/16959093


Considering a separate amplifier for (5) 4-OHM bookshelf speakers. Would like to learn some information before I make a purchase. I am Currently driving them with 6/8 OHM rated AVR. The room is 12x12 wondering how I would benefit by adding a separate amp to drive these and if it is even worthwhile for my application. Basically, would I have a noticeable difference? Any recommendations or suggestions would be appreciated.

Your room is quite small, so you shouldn't need a lot of power to get high volume. But if you wanted to add some additional processing to the signal such as an equalizer, most receivers have no means of adding that into the loop. So the only way is to have a separate pre-amp and power amp, with the EQ in between.


The claims of wonderful sound improvements for separate power amps are unsubstantiated.
 

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The only way to tell if you get better sound with a separate power amp is to listen and decide for yourself. Some hear an improvement, some don't. Your room is small but a lot depends on how sensitive your speakers are, how much sound absorption your room has, and how loud you like to listen to movies/music. As a previous poster said, it takes a huge increase in power to noticeably increase the average SPL (sound pressure level). Most listening requires only a few watts if the sound level is steady, but that changes drastically when dynamics enter the picture. If you want to hear explosions or music in anything approaching realistic levels your system may require several hundred watts of power at 4 ohms to reach that without damaging your speakers because of compression and/or clipping during dynamic peaks. That is one of the main benefits of a separate power amp because few receivers can produce that kind of clean power, and probably none of the usual mass-market receivers will do so. Receiver features change constantly in an attempt to get owners to constantly upgrade (hopefully before the receiver burns itself out). But a good amplifier is a good long-term investment; most will last for years without any issues, and many have 5 year warranties or longer (Bryston amps get 20 years; Paraound 10 years; Classe and Sanders amps get lifetime warranties). I moved from a receiver to a separate amp primarily to assure the good health of my speakers, which were a major investment. And over the years I have found subtle but distinct differences in what each amp produced sound-quality wise. But that is just me, and you may not hear that at all. IMO a separate power amp is a sound and worthwhile upgrade for most receivers which can be used as a pre/pro, and there are some great used amp bargains to be had at Audiogon and Videogon. That is where I bought my current amp as a demo unit with full warranty. Anyway, as I said, the only answer to this question is a personal one and only you can make the call.
 

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Be careful with all those calculators and such. According to some calculators all I need is 80 watts to peak at reference levels. I used a McIntosh 160 watt amp and I clipped it at dynamic peaks. I use a 750 watt amp now and I never clip anymore. Amps are cheap now and more power the better. I also agree with dsmith901.
 

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As already asked ... what is the current receiver? I seriously doubt any receiver described as 6/8 Ohm rated is what you want driving a 5 x 4 Ohm speaker set, even in a small room. There are exceptions but we would need details from you first.


In your situation I would concern myself less with wattage and more with impedance rating, although the rule 'more watts is better' is good to follow when comparing Watt/price ratios. A Parasound HCA855 will very likely drive your speaker set but as MKtheater says avoiding clipping/distortion is another matter altogether. Buy more than you need within a reasonable price target and consider it insurance.


If you decide to go with external amping I highly recommend Emotiva for performance/value.
 

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The original reason for separate amps (from the original days of hi-fi) is still the best reason for separate amps....


The pre-pro becomes obsolete and the controls wear and get noisy, but the power amps, if you can assume they were selected so they will be powerful enough and were put together well enough, will last for decades without a major loss of performance.


So IMHO, you only need to shop for your amps a couple of times in a lifetime. You can then concentrate your $$ and your critical effort on the continuous review and upgrade of your speakers, your audio sources and last but not least the pre-pro used to control the rest of the system.
 

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Quote:
Originally Posted by deadhead_30yrs /forum/post/16988681


The original reason for separate amps (from the original days of hi-fi) is still the best reason for separate amps....


The pre-pro becomes obsolete and the controls wear and get noisy, but the power amps, if you can assume they were selected so they will be powerful enough and were put together well enough, will last for decades without a major loss of performance.


So IMHO, you only need to shop for your amps a couple of times in a lifetime. You can then concentrate your $$ and your critical effort on the continuous review and upgrade of your speakers, your audio sources and last but not least the pre-pro used to control the rest of the system.

Except that Pre-pro's cost WAAAAYYYY more than all but the most expensive AVRs and often with fewer features and less up to date technology.


Separates are generally only worth it if you have vast sums of money to blow on audio equipment or have speakers which, absolutely require a separate amp.
 

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Actually the Onkyo 886 PRO was not to bad in price and had a lot of nice features (very good video processing). I would expect the new 887 PRO to be even better! Still though, you can easily use a very good or great receiver as a pre-pro. That way you can easily A/B them to decide what is best for your room...
 

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Quote:
Originally Posted by joerod /forum/post/16988828


Actually the Onkyo 886 PRO was not to bad in price and had a lot of nice features (very good video processing). I would expect the new 887 PRO to be even better! Still though, you can easily use a very good or great receiver as a pre-pro. That way you can easily A/B them to decide what is best for your room...

The Onkyo 885/6/7 are one of the few exceptions, as will the Emotiva UMC-1 (whenever that gets released).


But most pre-pro's have prices that don't even start until $1,500 or so and most of them are well more than that.
 

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My point is that the pre-pro section needs to be looked on as disposable.

This part of the system (or the whole reciever if that is the way you want to roll) are now just like PC's because they are PC's with a much better user interface and I/O.


If this is fact, then I would never recommend that anyone spend more $$ on a pre-pro than they can afford given it's imminent (two to three years) obsolesence.


BTW - I have owned at least 10 different pre-amps (now pre-pros) over the past 35 years. In the same time, I am only on my third "set" of power amps.
 

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Quote:
Originally Posted by TPnBobcats /forum/post/16988877


The Onkyo 885/6/7 are one of the few exceptions, as will the Emotiva UMC-1 (whenever that gets released).


But most pre-pro's have prices that don't even start until $1,500 or so and most of them are well more than that.

Good point. But still they are good enough to be considered...
 

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Tp, are you saying that for i.e. $1,700> Emotiva UMC-1+ EPA 5, that you "should/could". Beable to get a equal or Superior AVR?


Not starting a debate- I am starting to "interview" a new amps/pre/AVR. The Emotiva comp looks attractive. But if i can get the same "audio/video" quality in one unit it will cut down on interconnect/cables and WAF issues. And my not have to purchase a new rack..

TX,

db
 

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Quote:
Originally Posted by DAB /forum/post/16998603


Tp, are you saying that for i.e. $1,700> Emotiva UMC-1+ EPA 5, that you "should/could". Beable to get a equal or Superior AVR?


Not starting a debate- I am starting to "interview" a new amps/pre/AVR. The Emotiva comp looks attractive. But if i can get the same "audio/video" quality in one unit it will cut down on interconnect/cables and WAF issues. And my not have to purchase a new rack..

TX,

db

Yes.


Now the amp section in any AVR that I know of, is not going to be as robust as an XPA-5 and the XPA meets or exceeds it's specs unlike the amp sections in many AVRs.


But for most people with most speakers, that isn't going to be a issue and we're talking about a 3db difference in volume at most for 8 ohm speakers. If you check out the thread I linked in my first post in this thread, it should cover the basic issues involved as to when you might or might not need an external amp.


But in terms of features and capabilities, any AVRs that I am familiar with in the $1,500 range, will match or exceed the UMC-1. Though we don't know yet exactly how the GUI, room correction and video processing will match up to the competition yet.


Personally I like the Emo stuff's look and think it ought to have higher WAF than your typical AVR. But I'm not a woman. Cabling differences between an avr and the Emo setup are really only the 5 cables from the UMC to the XPA.
 
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