Amps – how loud is 40W per channel?

I’m contemplating for my wedding music, rather than a cr*p DJ, having an mp3 player rigged to an amp and speakers. Cash is kind of tight so it’d be more of a ‘budget’ amp – I’ve been having a look on the net at a few – it might be a question that’s not easy to answer, but how loud is an amp with 40W RMS per channel? The room’s not huge (wedding’s only for 50 people), so the sound doesn’t have a huge space to fill. Feel free to post links to anything amps you think might do the job.

PS I already have a set of big speakers from a dead Kenwood ‘midi’ system that put out some serious volume, so I suspect these would be up to the job.

Cheers!

how long is a piece of string

‘loudness’ is determined by the sensitivity of the speaker, normally in the range of 80-100 dB

an increase in 3dB sensitivity will have the same effect as doubling the power of your amplifier

As a guide, for our wedding we used 2×2.4KW amplifiers driving 2 mid/top speakers and 2xsubwoofers.

sensitivity is measured as the sound pressure level, usually wieghted to represent human hearing (A weighted) when an input signal of 1W is measured at 1 meter (ie the speakers we used are rated at 96dBA@1W@1)M

if i had my college notes i could tell you how to work the two out. but i’m at work using the very things i should know about form college (and have forgotten) so i can’t!

40w RMS will easily fill most rooms, but might struggle with a village hall type room.
You might be better trying to buy a stereo amp with two pairs of speaker outputs if you can. That way you can have 4 speakers working at half power in different spots of the room.

rough dimensions of room are?

CHB – cobblers.

40W will fill a medium sized living room with most hifi speakers. add a high ceiling, lots of people and the hubub that people produce and it’ll be pissing in the wind.

i’d recommend you speak to a local PA hire company and ask them to give you a price for a suitable setup, then haggle them down by 30%. if you are vaguely competent you can set it up yourself. a helpful company will show you how to do this if you are nice to them/buy them a beer.

which is why I asked for the dimensions!

It’s certainly not village hall size – maybe 15m long x 10m wide x 4m high, give or take.

Michaels right though to suggest hiring a PA system, they are really not expensive.

or for a single use, this[/url] would do the trick. you could stick it on the bay after. not gonna be the best quality by any stretch but it’ll work

Thats not far off the size of my village hall!
Its about 10x the volume of my living room, and I have a big living room (7×3.5×2.5).

I reckon you will need a PA. I am sure Michael will check his revision notes tonight and give you a definative answer 😯

I’m with MrMW here – I think 40w/channel will be lost. Particularly once the amp starts getting hot and it all starts clipping….
I would also suggest hiring an amp and speakers from a PA company. A friend did this for his 18th birthday and got a huge pair of speakers and a pretty meaty amp for not a lot of cash.

Is that Peavey system 100w RMS per channel? OR is it PMPO or is is 100W combined on both channels?

Also for a large room, I would say getting the speakers above head height is important, otherwise you are just deafening the dozen people next to the speakers, and nothing travels to the back of the room.

Surprisingly loud in a quiet room, but it depends a lot on what you want it for, and what the sound of the room will be like (and how loud you like your music – if it’s just background classical music, or if it’s full on headbanging party music). When you’ve got people chatting, it makes a real difference.

Personally I reckon the easiest way is to just hire a small PA – if you phone up your local dj hire shop, ask em for an amp, and a couple of speakers, stands etc, it’ll probably cost you £50-£100 for a day hire depending on where you are in the country. Make sure they know what you’re going to plug into it, and that they don’t want to hire you something with decks and all that included. They’ll probably have a preset ‘small PA’ hire or something. Make sure they bung in a lead to plug the ipod into the amp or mixer. They probably won’t hire anything less than 100w, personally I’d spend a little bit more and get something loud, it’s hard to have too loud a system, whereas a weedy one will spoil the day (although don’t get something too massive obviously as it’ll take up loads of space and be a waste of money).

Oh yeah, and my top tip is to playlist it in advance, and don’t let people plug in their own ipods, as the people who have brought ipods with them will inevitably be the people who are into My Chemical Romance or some such nonsense that really isn’t happy wedding music, or worse, they’ll have an ipod loaded full of Cliff Richard numbers. If you’re having a meal then a party, think about what kind of music you want when, there’s nothing worse than a 1000W PA blasting out happy hardcore when you’re trying to eat (okay there are probably much worse things, but you know what I mean).

Joe

MMW is right. haven’t mentioned ohms though as this IIRC halves the value ie 40w into 8ohm is 20w into 4 (or is it 16?)
40w driving a horn loaded 105db for 1watt at 1 meters sensitive speaker will fill the room but will not if it has to drive a 86db/1w/1m richer sounds special.

Is that Peavey system 100w RMS per channel? OR is it PMPO or is is 100W combined on both channels?

50w RMS per channel. I’d go for the hire route personally rather than buying something and ebaying it.

Joe

Thats not far off the size of my village hall!

Yeh, I thought that after I posted – I may ahve overestimated the size, it’s a while since I’ve been in the room!

It’s a difficult one as it isn’t a traditional disco/dance type do, more of a sophisticated soiree (ha!) so I kind of wanted to steer clear of the huge speaker/PA set-up, but if that’s what it’s going to need then so be it, thanks for the help.

they don’t need to be huge.

if you can find a local hire company then say you want something similar to the Nexo PS8 series.

probably need

2xPS8
2xLS400
1xPS8 controller
2xamp of some kind (Nexo is the same company as an amp maker called Camco, the two usually com together)
a small mixer of some kind
cables and stands.

with a sub/midtop set up like that they should have a pole that fits in the top of the sub and supports the midtop at eye level. this looks much neater than a big cabinet on a stick

you might even get away without the subs, depends on the kind of music really

of course, if you want to do it properly i can get you a very good price on a proper PA

i’ll even come and install it myself

people will certainly remember your wedding 🙂