| CARTRulz |
Hi guys,
I've heard a lot of discussion between the quality of home theater amps vs. pro audio amps. For something like 300 bucks you can get a 200 watt home theater amp, or you can get like a 750 watt pro amp. Now I've heard home theater watts referred to as "real" watts, and pro watts as "fake" watts, meaning that the pro amps have very little current, and if I'm correct, current is what we want to move these speakers. So, any thoughts/ideas? I'm asking becasue these Snell subs I have are rated at 600-1000 watts, and so I could either spend 300 bucks on a 200 watt stereo amp, and still underpower them, or i could spend the same 300 bucks on like a Behringer EP2500 that puts out something like 600 watts at 8 ohms. |
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| xstephanx |
the EP is a SOLID amp, and from what ive read it DOES put out rated power(depending on THD, a bit more).
Ive heard that usually prefer the sound of pro amps over plate amps for subwoofers, many people have said that they sound "cleaner" and "tighter"
also the eztra headroom on the EP would help.
BUT if this is for a HT setup, you have to know that the input sensitivity is LOWER meaning you might need a booster, although iev never heard of anyone having to resort to a booster(doesnt mean it doesnt happen). |
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| pinkmouse |
| There is a lot of snobbery regarding pro amps in the audiophile world. Yes, some do sound rubbish, and you have to be aware that quoted power figures are usually into 4ohm, but for driving subs a good pro amp is an excellent choice. I haven't heard the Behringer, as it is at the lower end of the market, but I'm sure it will be fine for you. If you want to spend a little more, look out for s/h kit like C-Audio, Crown, (not the Powerbase series), or QSC. |
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| Nigel Goodwin |
| quote: | Originally posted by CARTRulz
Hi guys,
I've heard a lot of discussion between the quality of home theater amps vs. pro audio amps. For something like 300 bucks you can get a 200 watt home theater amp, or you can get like a 750 watt pro amp. Now I've heard home theater watts referred to as "real" watts, and pro watts as "fake" watts, meaning that the pro amps have very little current, and if I'm correct, current is what we want to move these speakers. So, any thoughts/ideas? I'm asking becasue these Snell subs I have are rated at 600-1000 watts, and so I could either spend 300 bucks on a 200 watt stereo amp, and still underpower them, or i could spend the same 300 bucks on like a Behringer EP2500 that puts out something like 600 watts at 8 ohms. |
You're completely the wrong way round, PA amps are 'proper' honest watts, and cheap home audio systems are the ones that specify 'imaginary watts'.
Any decent manufacturer though will only specify RMS watts, and it's that you should look for. Your home theatre amp is more expensive because it includes a LOT more, more channels, preamps, possibly a decoder as well, maybe even a tuner?.
I really don't think you need to run an EP2500 for a home sub-woofer though - it will certainly 'move' them, it might move them next door though!. |
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| CARTRulz |
Cool, thanks guys.
I actually have looked at Crown and QSC, they seem to be real nice. I'm not really worried about overpowering them, as they are Snell SUB1800's that go for about $2500 each brand new, and theyre speced at 600-1000 watts. I only ask becuause these are subs that are made to be "clean" and "tight" and arent really made for "boom box" applications, although they certainly have an immense of output. I was just curious about the power ratings and the power quality, as I'd probably go with a low distortion and "clean" amp over something thats gonna push the sub to lots of output but make it sound muddy. |
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| Nigel Goodwin |
| quote: | Originally posted by CARTRulz
Cool, thanks guys.
I actually have looked at Crown and QSC, they seem to be real nice. |
The Behringer EP2500 is pretty well identical to one of the QSC models, as QSC haven't taken them to court?, it seems likely they both buy them from the same Chinese manufacturer?.
Certainly Behringer don't copy equipment to the extent of cloning, only the general idea and often the look! (which did get them in trouble with Boss). |
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| Relax |
Quick question, what would you guys think about this amp:
http://www.gemsound.com/products_amplifiers-pa4505.html
I can get it for under 300. Is there perhaps another amp that will do better similarly priced? 300 is my max, and I need soemthing like 700wrms into 4 ohms. (Well, I don't need that, but my subs would like it)
Thanks Ahead of time!
~Jerick |
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| Relax |
Just some more info on the amp above.
I spoke with a customer service rep, and He said the amp uses a 250v 15 amp fuse. Does this work out to be a max of 3750 watts? So the numbers listed by the manufacturer are acceptable?
Also, can I expect the 800 wrms per channel on 110v? |
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| Nigel Goodwin |
| quote: | Originally posted by Relax
Just some more info on the amp above.
I spoke with a customer service rep, and He said the amp uses a 250v 15 amp fuse. Does this work out to be a max of 3750 watts? So the numbers listed by the manufacturer are acceptable?
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No, 1650W - your mains is 110V, on 230V mains the fuse would be dropped accordingly (perhaps 8A?). Fuses don't really have voltage ratings, it's just the voltage it's guaranteed to break reliably.
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Also, can I expect the 800 wrms per channel on 110v? |
Yes, it'll be a 110V amp for the USA. |
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| just a guy |
I concur. Line voltage x fuse amperage = potential wattage
110v x 15a = 1650 potential peak watts x amp efficiency (described by a fraction of 1)
fuse voltage does not matter in this equation |
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| Relax |
So in your opinions, is the amp rating given by the manufacturer, 800 wrms per channel at 4 ohm stereo, realistic?
Thank you for the help so far! |
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| just a guy |
Ya, I'm getting a bit confused myself, I hope maybe Nigel can clear this up.
I'm not sure if the formula I stated results in peak watts or RMS. It's been a long time since I thought about it. Doing the math on a couple of car amps I have would seem to indicate RMS is the right answer.
Remember, this is a very loose way to estimate potential power anyway, it depends on a lot of variables including specific design, class of operation, etc.
Given the simple fact that it is pro gear and actually has power meters I really don't think they are lying. |
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| MOER |
Firstly there is NO SUCH THING as "Watts RMS"
Wattage is volts x amps or volts.volts/impedance or amps.amps.impedance.
So having a number squared and then divided or multiplied by some other number can NOT give you an answer with a "root mean square"
Square root of 4 x square root of 4 does NOT = square root of 4 but just the number 4. The "root mean square" is gone.
The term is continuous power, no more no less.
Pro amps of the Crown, QSC, Crest, Peavy etc MUST meet their spec. Mnay of these amplifiers are used in situations where the specs must be strictly adhered to. The el cheepo "pro" amps are just that.
Home amps that meet FTC requirements MUST meet published power specs:drink: :hphones: |
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| just a guy |
Of course, that makes sense. Obviously I type without thinking sometimes.
So 1650 watts continuous is the max the amp can draw. Extrapolate this number with reference to the amp's class efficiency and that should give a very rough ballpark of continuous watts output.
If this is the case the numbers might be a bit optomistic but wouldn't seem blatantly false. There are many other factors that play a role here.
So is this brand reputable or el cheapo? It was glaringly absent from your list so... I'm guessing that's insinuation by omission. |
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| richie00boy |
It's el cheapo, likely with inflated power figures. These cheap 'pro' amps are just not in the same league as a real pro amp and is why the real pro amps get a bad name. Real pro amps can easily compete with the best high end audio gear, cheap ones cannot and sometimes are even worse than a decent home audio amp.
I would expect to pay £1 per honest watt for a proper decent pro amp. At today's exchange rate that's $1.86 |
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| just a guy |
Point well taken.
However home amps just can't compete with this kind of brute power. It will only see use as a sub amp anyway, and probably not driven to capacity.
For the price difference for someone like me on a budget, is this still not a viable alternative to real pro gear in the situation described? Which physical parts and/or sound quality factors are inferior? |
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| richie00boy |
For a sub a cheap high power amp will be ok. I say again though that the power ratings will be inflated. But if you buy at least double the watts you need you will be ok.
As to what's inferior, where do I start... |
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| jaredl |
| Parts Express has a pretty good sale on Crown amps. Their ratings are a lot lower than the Behringer but if the Behringer only does half of rated power they may be about as powerful. |
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| BlackCatSound |
The behringer will do its rated power, I have a couple as hire amps and they are too bad. (less risk than hiring out a £3k amp and 1/3rd the weight)
The EP2500 is a copy of the QSC RMX series. Its class H, not exactly the most hifi amp out there and the fan is a bit noisy. The design is quite sound though. There are better amps but not for that money unless you go for second hand.
A good pro audio amp will have been designed to run all day and night close to its limits. I've done gigs where the amp clip limit lights have been on more than they have been off and they just keep on playing.
There are a lot of 'DJ' amps out there that are just pure cr*p. They are perfect partners for the big red DJ speakers with the big peizo horn and the 4 peizo bullets across the top :)
Personally I run a Chameleon 2 amp for my hifi. Lovely amp and only 1U high. |
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| pinkmouse |
| quote: | Originally posted by BlackCatSound
Lovely amp and only 1U high. |
But about a metre deep! ;) |
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| BlackCatSound |
| quote: | Originally posted by pinkmouse
But about a metre deep! ;) |
Only half metre :) |
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| pinkmouse |
| Not the 1100 then. ;) |
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| BlackCatSound |
| Nah, this is the baby of the bunch. I only drive a pair of 5.25" bookshelf speakers with it :) |
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| Nigel Goodwin |
| quote: | Originally posted by jaredl
Parts Express has a pretty good sale on Crown amps. Their ratings are a lot lower than the Behringer but if the Behringer only does half of rated power they may be about as powerful. |
As I mentioned previously, decent gear will only publish real specs, pro-audio ALWAYS gives proper RMS ouput powers, and can be trusted to do so.
I know there's always this rubbish about "it's not RMS watts", but that's just semantics - EVERYONE knows what it means, and it's been used in specs since before WWII.
If people want to be pedantic?, how about "the output power in watts, obtained by multiplying the RMS output into a fixed load impedance, and dividing it by that load imedance, at a fixed low distortion rating and a specified frequency or range thereof"
That seems rather a mouthfull to me?, I'd sooner read Watts RMS, "continuous" seems far too ambiguous?. |
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| MOER |
Dear Nigel,
Coming from a country that uses the metric system where the power of a motor vehicle is specified in Kw and not Kw RMS |
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| Cloth Ears |
| quote: | Originally posted by MOER
Dear Nigel,
Coming from a country that uses the metric system where the power of a motor vehicle is specified in Kw and not Kw RMS |
But isn't RMS simply a way of descibing the power output based on amplifying a wave form, rather than a "flat" signal? Because all sound is made up of various sine wave forms, over the period of one wavelength the signal averages to 0.707 (or square root of 0.5) of the peak signal. This is where 'Root Mean Square' comes from. So, for any RMS figure, you should expect (no, demand:)!) peak figures of 1.41 time that.
In a car, the measurement is actually averaged over a number of cycles of the engine, as it is not possible to measure it over 1 pistinn cycle only. The cylinders (and crankshaft, etc) make up one rotating unit which has to be brought up to speed before meaningful measurements can be taken. But you could work out what the theoretical output of the engine would be, and I would expect it to be 1.41 time the actual measured output in kW. |
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| Nigel Goodwin |
| quote: | Originally posted by MOER
Dear Nigel,
Coming from a country that uses the metric system where the power of a motor vehicle is specified in Kw and not Kw RMS |
Check your countries! :D
In the UK engines are specified in horsepower!. |
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| Relax |
PE has these with free shipping:
http://www.partsexpress.com/pe/psho...747&ctab=2#Tabs
Although I think its kind of ugly, is it a guaranteed performer? Perhaps someone else has used it and can give me a short review on rated power output and clarity for use with subwoofers?
Thanks again guys!
~Jerick |
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| phase_accurate |
| quote: | | I know there's always this rubbish about "it's not RMS watts", but that's just semantics - EVERYONE knows what it means, and it's been used in specs since before WWII. |
No it is NOT just semantics it is maths and physics !
Regards
Charles |
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