What Wattage for my bedroom?

 

New member
Username: Bartleandy

Post Number: 1
Registered: Aug-05
Hey guys.

Im new to all this and im just looking at purchasing an amp + a few spekaers for my bedroom. It will be connected to my computer.

My room is about 6m by 7m.

I was looking at impendance 8ohms as usual. Is this a good choice?

I also have no idea what wattage I would need? It needs to be loudish but not so loud my window breaks. What would you reccomend?

Remember I am a student on a budget!

Thanks
Andy.
 

Silver Member
Username: Cheapskate

Post Number: 218
Registered: Mar-04
for a small room, 50 watts should be adequate for typical listening unless you're using really inefficient speakers.

THAT has just as much effect on volume as amplifier power. every time you lose 3dB of speaker efficiency, you need to DOUBLE amplifier power to get the same volume level.

many tube fanatics with high efficiency speakers use amps with as little as 2-5 watts!

a 90dB efficient (typical) speaker will play at 90dBs with one watt of power. 2 watts = 93dB 4 watts = 96dB and so on.

there's a whole school of hi-fi caled "eye-fi" (mostly british) where people only use 20-30W amps feeling that bigger amps are less refined sounding.

my 89dB mission speakers can get up and boogie decent enough with my 20 watt yamaha boombox amp. at one point, i was using this setup as my SUBWOOFERS for my tiny superzeros.

the best rule of thumb that i've read is that regardless of power rating, it's THE FIRST WATT that counts.

i'd bet you could get by with 30 watts easily with typical speakers depending on what YOUR definition of loud is.

some people aren't satisfied with anything short of hearing destroying party volume levels, while sensible listeners typically listen at 80dB or so most of the time so they can hear another day.

tough question to answer, hope this helps.
 

Silver Member
Username: Cheapskate

Post Number: 219
Registered: Mar-04
on a budget... just get a $100 reciever (sometimes 100watts) and a nice $200 pair of bookshelf speakers and a cheap DVD or CD player.

at the $200 mark, PSB and Paradigm are two of the best values, but there are a few other brands that are nice for the price too. PSB ALWAYS seems to come up in bargains for the price reviews... and almost every other member here brings them up as well when budget isa concern.

if you REALLY want to save money... there are huge bargains to be found on ebay if you're persistent and patient.

i found my NHT superzeros ($250 1st pair, $188 2nd pair on closeout) are super bargains that i prefer over $1000 B&Ws except that they have no bass at all.

the big question really is WHAT'S YOUR BUDGET?

whatever it is... try to put close to half or more of it on the speakers as those have the biggest impact on sound.

JVC ir reintroducing it's famous "kaboom box" portable with huge sounding 50 watt X 6 1/2" woofer bass. even used, they were selling for $400+, but now they'll be around $300 again new.

the nice thing aboout them is that you can take them with you anywhere. they aren't high end by any means... but they are definately loud.
 

Silver Member
Username: Diablo

Fylde Coast, England

Post Number: 208
Registered: Dec-04
Budget minded posted whilst I was writing. I gennerally agree with his posts.

I've not bothered to change my reply though -

8 ohms is a good choice. Anything else and you will have much fewer choices when matching it with a lower price amp.
The room is quite big. You need to look at the efficiency of the speakers.
It takes 4 times as many watts to drive a speaker with a sensitivity of 86dB than it would one with 92dB. You have to double the watts to get a 3dB increase in volume. (just in case anyone notices, I admit that this is a paraphrase of a previous answer BTW, lol).

The manufacturer's sensitivity rating of speakers is sometimes wrong though. You really need to hear them yourself, preferably with the amp which you may be thinking of buying.

For example, I have Castle Conway 3 speakers as my my fronts, these are rated at 89dB by the makers, but reviews measure them as 91dB. My surround speakers are rated as 87dB, but are probably lower, as I need to feed them via my pre-outs via a separate amp to get them to be audible.

Yep, go hear stuff, then decide. :-)

 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5094
Registered: May-04


Try a 5 watt SET and a pair of single driver speakers. There will be magic in the air and all your friends will be jealous.
 

New member
Username: Margie

Napa, California

Post Number: 2
Registered: Aug-05

What is "SET" ?
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5107
Registered: May-04
Single Ended Triode.

It usually refers to a vacuum tube amplifier.

In general, a vacuum tubes is a more linear device than a transistor.

A triode, whether tube or transistor, is the simplest gain stage available.

The triode was designed at the turn of the last century by Lee deForrest.

Single ended refers to the operation of the circuit which does not hand off the + and - sides of the sinewave to different amplifying stages.

The single ended design passes the complete waveform through one device.

Splitting the sinewave between two output devices is considered Push-Pull operation. It produces more power but less linearity. Most amplifiers run in Push-Pull operation.

By keeping the signal path as simple, and linear, as possible and pasing it through the simplest loudspeaker design (a single driver), coherence is increased over a Push-Pull amp running through multi driver speakers.

Less "stuff" between input and output should equal more music at the speaker terminals.


http://www.vac-amps.com/page0004.html

http://www.stereophile.com/interviews/399/


Let me know if you have more questions.


 

Silver Member
Username: Devils_advocate

Post Number: 190
Registered: Jul-05
"Less "stuff" between input and output should equal more music at the speaker terminals. "

Does "should" actually translate into real world performance or is that a subjective matter?
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5114
Registered: May-04


What in audio is not subjective or open to debate? If you want to know how to arrive at the conclusion concerning "more music", consider how much energy from source input to loudspeaker output is lost in heat. Much of it in the X-overs. Think about the phase shift that capacitors and inductors introduce to the signal path. Consider there is no free lunch and each gain stage introduces more nonlinearity, more distortion and more noise. Realize that no two gain stages are absolutely equal and, even in matched outputs, splitting the signal's + and - waveform will send the signal through two dissimilar gain stages and the result will be put back together at the outputs with a larger amount of negative feedback. (SET's generally run no negative feedback or a minimal amount of localized feedback.) Maintaining the same amplifying device throughout the signal's + and - swing will maintain the most liearity and introduce the least amount of phase shift. Take the phase shift away and you "should" be left with something that more closely matches the input of the original signal. Make the reproduction chain more efficient and you "should" end up with more of the original signal. Whether any one person will hear what is there is not something I can answer. We all listen in different ways for different qualities.




 

Silver Member
Username: Devils_advocate

Post Number: 192
Registered: Jul-05
"What in audio is not subjective or open to debate?"

Bose?

"Maintaining the same amplifying device throughout the signal's + and - swing will maintain the most liearity and introduce the least amount of phase shift. "

How big of an issue is this with push-pull designs, particularly as compared with the other problems contained within a typical stereo system?
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5123
Registered: May-04


What other problems am I comparing to? Do you know what "notch distortion" is?
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5124
Registered: May-04


You might have heard notch distortion called crossover distortion. It has to do with the class of operation a push pull amplifer runs in. Class A, B, C, etc.




 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5125
Registered: May-04


http://www.tubecad.com/september99/page2.html

http://search.yahoo.com/bin/search?p=class%20a%20operation%20audio%20amplifiers




 

New member
Username: Bartleandy

Post Number: 2
Registered: Aug-05
Thanks for your advice everyone.

The speakers I am looking at are 8ohm 100W with supposedly 90db sensitivity.

Does the amplifier's wattage need to match the speakers? In other words do I have to buy a 100W amp or can it be any wattage without damaging the speakers? If it is low/high wattage what affect will this have on the sound?

Secondly: if for eg I used a 100W,8ohm amp and connected two speakers to one output (the wrap wire around + screw in type) would both speakers be supplied 100W and 8ohm? Or would each speaker get half each (50W and 4ohm)? Sorry if this doesn't make sense!!!

And if the speakers did only receive half each (50W and 4ohms) and they where 8ohm + 100W speakers would they be damaged?

Thanks for all your help!!
Just trying to get into all this stuff, takes time to learn all the lingo etc!!

Andy.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5131
Registered: May-04



" ... would each speaker get half each (50W and 4ohm)?"



Yes, if you turn it up loud enough.



"And if the speakers did only receive half each (50W and 4ohms) and they where 8ohm + 100W speakers would they be damaged?"



Yes, if you turn it up loud enough!!!



 

Gold Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 1246
Registered: Feb-04
" ... would each speaker get half each (50W and 4ohm)?"

The combined load of two 8 ohms speakers will be 4 ohms. Each speaker would still get the same power as if wired alone if the receiver were still able to handle the double load. So the receiver would output double the wattage and each speaker would get the same as if wired alone.

"And if the speakers did only receive half each (50W and 4ohms) and they where 8ohm + 100W speakers would they be damaged?"

You'd damage the receiver (from the increased load) before you'd damage the speakers.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5142
Registered: May-04


Peter - First answer. In a perfect world, that is. We do not live in a perfect world.

Second answer. You'd damage the receiver (from the decreased load) before you'd damage the speakers. True, if the amplifier didn't go into clipping first. And, if the total impedance dropped low enough. We don't know, from the information provided whether that will actually happen.


I knew you'd appreciate the corrections.



The unanswered question, the "wattage" your speakers indicate has no bearing on whether you can do damage to them, Andy.






 

Gold Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 1251
Registered: Feb-04
Jan, for me load is the inverse of the resistance. If a load is more difficult to carry, then it's a higher load. Thus a lower speaker resistance is a higher load for an amplifier.

:-)

And you'd damage the receiver first because you shouldn't need to even drive it to clipping to damage it. But I agree you could damage both!
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5147
Registered: May-04


Here's the explanation I always gave to explain impedance loading.

A transistor needs a load to work (push) against to perform its function. Without a load on the outputs, no work can be done. Unlike a tube amplifier's typical transformer coupled output stage, most solid state amplifiers are direct coupled to the load. To get the most work done in the most efficient manner, the load is optimized to the point where the outputs are running in their most efficient range. In most cases this is an 8 Ohm load.

You can see this as a workman carrying a wheel barrow full of bricks. If he loads just enough bricks to allow him to efficiently push the wheel barrow up to the top of the hill, he gets the most work done in the least amount of time. An efficient use of energy. If he increases the impedance to doing his job by loading too many bricks, the work becomes harder and he has to exert more effort to get the work done. More bricks get to the top of the hill, but effort has to be expended. As long as the load doesn't exceed the capability of the worker, everyone is happy even if they are not efficient. If he decreases the load to the point where he is carrying too few bricks, he loses efficiency. As the number of bricks continues to drop, eventually no work is being done.

Think of yourself as the amplifier offering force against me as the load or, to make it simple, the resistance against which you are pushing. You're pushing me and I'm pushing back in the sense I don't want to be moved. At 8 Ohms we are both happy and you can get your job done well. If I increase my resistance (impedance) to you doing your job, you no longer do your job as efficiently. However, against my increased resistance, you are more stable (up to a point) despite less work is being done. If I begin to decrease the resistance to your force, you can extert more force with less effort. That works fine until I've decreased the resistance to the extent where you become unstable. If at that point I withdraw all the load from your effort, you will fall flat on your face. No work will get done.

You can see this as pushing a load uphill as the load increases and work getting done eficiently. And, you can consider the decreasing load as taking the wheel barrow down the hill and the lowered resistance eventually runs away from you. Either way, I see no way to make the higher resistance become less of a load.

I'm not an engineer; so I don't know of a formula that presents load as the inverse of resistance. I see four Ohms as being lower than 16 Ohms. To me that equates to a lower load at four Ohms.

Amplifiers generally get more stable as the load increases and less stable as the load is lowered. I don't see any way around that.







 

Gold Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 1254
Registered: Feb-04
Except that, as you say, 4 ohms is harder on an amp than 8 ohms because it sucks more current. Saying that a load is lower implies, at least to me, that it is easier (thus higher resistance).

load = 1/R
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5154
Registered: May-04



Whatever!
 

Gold Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 1261
Registered: Feb-04
I actually wore down Jan! Woo Hoo!
 

Silver Member
Username: Cheapskate

Post Number: 223
Registered: Mar-04
if you plan on cranking your speakers up to full volume, then too little power is a problem as you'll force your amp into clipping and THAT is what blows speakers most of the time.

easy rule of thumb... once you start to hear distortion... quit turning it up! LOL
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 5160
Registered: May-04


Peter - Arguing with a load of bricks is obviously futile. You're correct in that as the resistance increases the load is finally dropped.
 

Gold Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 1269
Registered: Feb-04
LOL!
 

mountainking!
Unregistered guest
Or you could always go with the setup i gave my room lol!

(6) paradigm studio 40's
Outlaw 990 pre/pro
outlaw 770 amp. (will be gettn the new one they are commin out with though)

im very happy with the way it all sounds.. thrilled actually. You should giver a go. lol as in watts, i have no clue of how many im pushin. but still sounds superb to me.
 

Bronze Member
Username: Rikmeister

Hometown, Pa Usa

Post Number: 37
Registered: Jun-05
have you thought of looking at used speakers or demos andy. there are some great buys on audigon and ebay. i would look at two good fronts and not worry about surrounds if i was on a tight budget. two great speakers will be better than 4 , 5 or 6 weak speakers. look at full range speakers. also you can get good receivers at the same place and also ubid has denon marantz and yamaha dumped there by the manufacturer. you can get some good buys and they are great receivers. remember you get what you pay for. cheap speakers mean lousey audio. look at used and be happy.
 

Silver Member
Username: Thx_3417

Post Number: 888
Registered: May-05
Upload

Andy,

Hear is the Stage-Accompany SPL db calculator easy to use, I use it my self sometimes for relaxation, however I wish I was born with two brains...

http://www.stageaccompany.com/new/support/splcalc.php

Ashley
 

Silver Member
Username: Joe_c

Atlanta, GA

Post Number: 974
Registered: Mar-05
I wish you were born with at least one!!
 

Silver Member
Username: Thx_3417

Post Number: 889
Registered: May-05
LOL< LOL<LOL

Upload

Any more jokes, well one would do just fine though, I was just thinking out loud....


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