# PA Speakers / Mixers and Power amps...



## pspdave (Jul 16, 2010)

Hi guys

Hoping someone can give me some advice...

I currently have a pair of Peavey Eurosys 1 150W RMS continous passive speakers. I would like to purchase a pair of peavey pro 15 mk2 300W RMS continous passive speakers.

With these two pairs, i would like to connect them all to a power amp, and separate Mixer. My question is.... how 

The Eurosys pair are 8 Ohm.. does that mean I will need the Peavey Pro pair to also be 8 ohm? (they come in either 4ohm or 8 ohm versions) Further to this, what kind/size of power amp should i be looking for? Also, are there any specific requirements the mixer will have to have in order to facilitate this?

I have heard terms like "2x300 watts at 8 ohms".. or "1000 Watts RMS into 8 Ohms bridged" .. what is a bridged connection? also, some people talk about connecting speakers in series or paralell.. whats that all about?

I was looking at the following power amp.. I am able to get a second hand one at a good price:

Peavey PV 1500 Stereo Power Amplifier | DV247

Would this suffice? any ideas for SIMPLE mixer to go with it? i dont need anything fancy, just something that will have the required connectors etc i need for my set up..

Any help would be super!

Apologies for the "newbie" ness of my question. 

Ta

Dave


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## DuckJordan (Jul 16, 2010)

let me be the first to ask you what are you going to use it for? also, what are your plans for upgrading in the future. Do you see yourself wanting more in the near future, and by simple mixer what are you wanting to connect to it. Simple could be something like an analog mackie mixer compared to the new sound craft Ilive series.


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## pspdave (Jul 17, 2010)

thanks for the reply..


Ill be using it for a duo act. myself an a singer. So vocals and guitar, an backing tracks running through the PA. As far as future plans, not likely to want to upgrade massively soon, possibly only with the addition of some wedge style monitor speakers. I've seen some really pricey mixers, but I only need to connect my ipod, vocals, and guitar to it. I assume as long as the mixer has balanced XLR's tats a good start?


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## DuckJordan (Jul 17, 2010)

pspdave said:


> thanks for the reply..
> 
> 
> Ill be using it for a duo act. myself an a singer. So vocals and guitar, an backing tracks running through the PA. As far as future plans, not likely to want to upgrade massively soon, possibly only with the addition of some wedge style monitor speakers. I've seen some really pricey mixers, but I only need to connect my ipod, vocals, and guitar to it. I assume as long as the mixer has balanced XLR's tats a good start?


 
Well, with a vocals and a guitar your going to want a min of 4 XLR ports, 2 for vocals (one for backup just in case one doesn't work), and 2 for guitar one on direct and one miced on the amp. then as far as backing tracks you could run a cheap CD or MP3 player through the tape in RCA connectors. So it sounds like you need a small DJ mixer...


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## bishopthomas (Jul 17, 2010)

DuckJordan said:


> ... the new sound craft Ilive series.


 
Just for clarification, Allen and Heath make the iLive. Soundcraft's digital consoles are the Vi# series.


DuckJordan said:


> then as far as backing tracks you could run a cheap CD or MP3 player through the tape in RCA connectors. So it sounds like you need a small DJ mixer...



Be careful about the tape inputs. Some consoles (especially the Mackie SR series) will mute all other inputs when the tape in button is engaged. Also, please stay very far away from DJ mixers. They are designed specifically for DJ's. They have terrible control and routing, and I'm pretty sure the OP will have no need in cross fading while playing guitar.


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## bishopthomas (Jul 17, 2010)

Lots of questions, so here we go...


pspdave said:


> I currently have a pair of Peavey Eurosys 1 150W RMS continous passive speakers. I would like to purchase a pair of peavey pro 15 mk2 300W RMS continous passive speakers.



You're replacing the Eurosys, adding monitors, or want all 4 to be your FOH speakers? If the latter, what is your reasoning. I would put the Pro15's as FOH, the Eurosys as monitors, and call it a day.


pspdave said:


> The Eurosys pair are 8 Ohm.. does that mean I will need the Peavey Pro pair to also be 8 ohm? (they come in either 4ohm or 8 ohm versions) Further to this, what kind/size of power amp should i be looking for? Also, are there any specific requirements the mixer will have to have in order to facilitate this?



It depends on how you plan on connecting them. In general, if you plan on daisy chaining (connecting in parallel) then you'll want 8 ohm cabinets. Most low end amps are not capable of handling 2 ohms, which is what you would get by daisy chaining two speakers. Which brings me to the math. Ohm's Law: Total Resistance = (resistance1 * resistance2) / (resistance1 + resistance2). If the speakers are matched then dividing the resistance (actually impedance) by two (the number of speakers you are connecting) is a shortcut. So two 8ohm speakers will give you a total load of 4 ohms, two 4ohms will give you 2ohms, etc... So when your amplifier is rated for say 400 watts at 4 ohms that means that when you plug two speakers into it the amp is outputting 400 watts. Since you have two speakers on that 400 watts, each speaker is getting half of that.


pspdave said:


> I have heard terms like "2x300 watts at 8 ohms".. or "1000 Watts RMS into 8 Ohms bridged" .. what is a bridged connection? also, some people talk about connecting speakers in series or paralell.. whats that all about?



Power amps are generally two channels. "2x300 watts at 8 ohms" means that each channel of the amp produces 300 watts with an 8 ohm load. Most amps will allow you to combine those two channels in order to get more power, but that means that you cannot power as many speakers since you still have to take into account your impedance load. You can also set an amp to operate with stereo outputs but parallel the inputs. This will allow you to send it one signal (into channel 1) and will duplicate that signal to both outputs, keeping your original "2x300 watts at 8 ohms" spec in tact.


pspdave said:


> I was looking at the following power amp.. I am able to get a second hand one at a good price:
> 
> Peavey PV 1500 Stereo Power Amplifier | DV247
> 
> Would this suffice? any ideas for SIMPLE mixer to go with it? i dont need anything fancy, just something that will have the required connectors etc i need for my set up..


 
That amp would work as long as you don't try to drive it too hard. It sounds like you're probably doing the coffee shop/bar scene, so you should be okay with that. As far as mixers, maybe take a look at Behringer's web site. I'm not a big fan myself as their quality control is some of the worst around, but for bang for buck it's hard to beat. I would go for at least 6 channels, but probably 8 to handle any kind of future expansion. How will you ever plug in your accordian for polka night if you don't leave yourself an extra channel? For connections, I would connect the left output (or mono if it has one) to one side of the amp for FOH speakers, then use an aux out to channel two of the amp for monitors (foldback). Now you'll have separate control over what you hear on stage, which is good if you like the tracks (or whatever) louder than they should be in FOH. Or if you just want to hear the same mix as FOH then go from the console's Left output to the amplifier, set it on parallel inputs (but not bridged mono!), and connect the two FOH speakers to one side and two monitors to the other.


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## pspdave (Jul 17, 2010)

Wow thanks bishopthomas.. you know a lot of stuff!! i enjoy learning curves! I think your'e right, ill use the Pro15's as FOH, the Eurosys as monitors. I am now in a position that i am considering the following two setups:


x1 THE T.AMP TA1050 MK-X - U.K. International Cyberstore
x1 THE T.MIX MIX 1622 FX - U.K. International Cyberstore


OR

x1 THE T.MIX DPM 1094 - U.K. International Cyberstore

Obviously the choise is between separate amp an mixer Vs amp/mixer... In either case, with +- x2 500RMS, i should be ok  Although the Peavey PV 1500 is a lot more powerful.
and your absolutely correct, doing the small pub thing. your idea of using Aux out for the monitors is superb! exactly what I want. Otherwise, I will end up having sound blasted in my face! 

The T.Mix range seems to have good specs, and its a toss up between the unpowered one, or this Yamaha:

Yamaha MG82CX Compact Mixer - Absolute Music UK Online Store

It is truley frightening how much there is to learn.. an all this so some punters can sing along to Sweet Child of Mine whilst drinking a pint! I love this stuff


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## bishopthomas (Jul 17, 2010)

It's no problem at all. And there's always plenty more to learn. I usually learn something new everyday, certainly every day that I use this kind of equipment. The learning never stops, and there's always someone out there smarter than you, so never feel too timid to ask a question.

I'm not familiar with those particular pieces of gear and don't have time to look up the specs right now, so can't comment on those specifics. I thought about addressing the powered mixer idea earlier but decided not to add more fuel to the blazing inferno. Powered mixers are convenient and easy to tote around but they typically do not have all the features of a "real" mixer. Also, if it goes down you're screwed. You lose an amp channel and you just don't have monitors for the night. Lose the powered mixer and you'd better be able to sing Sweet Child of Mine louder than the drunken saps in the pub.


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## pspdave (Jul 18, 2010)

Yea i see what you mean. I think as long as the power amp i choose has more than enough power for what i require, I should be ok  I would rather have too much, than too little! 

I don't suppose you have any recommendations with regards to power amps that you have had experience with? or separate Mixers for that matter.

From doin research, i have gathered that although there are a lot of power amps that boast loads of power etc, the price belies there specs. If it looks to good to be true, it probably is!


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## museav (Jul 18, 2010)

pspdave said:


> Yea i see what you mean. I think as long as the power amp i choose has more than enough power for what i require, I should be ok  I would rather have too much, than too little!


No, what you really want is the power that you require. "Too much" power is not a problem in the right hands as an experienced operator that knows the system well can still run it within its limitations. But just as someone trying to get too much from an underpowered system can be a problem, so can be someone misusing an "overpowered" system. Determining what is the appropriate power for a system can involve considering the type of music, the output required, the skill of the operators, the processing and capability of the system, etc. Where such specific information may vary greatly or is not known, a general recommendation of 1.5 to 2 times the rated continuous or long term power of the speaker is suggested.

I keep saying this, but one factor that commonly gets overlooked in discussions like these is sensitivity, which is the rated output of the speaker for a given input level. A speaker with a greater sensitivity can output the same level with less power compared to one with a lower sensitivity or provide greater output with the same power. If you have two 8 Ohm rated speakers and one is rated at 100dB/1W/1m sensitivity and the other at 97dB/1W/1m sensitivity, then the one with the higher rating will be just as loud with only half as much power. So while many people assume a 1,000W rated speaker will be louder than a 500W rated speaker,there really is no such direct relationship, one has to also consider the sensitivity or how well the speaker converts that electrical energy into acoustical output.


On power amp ratings, one must look very carefully at the conditions for the rated outputs. Many "X Watt per channel" amps base that number on lower impedance loads and at a single frequency so that they can publish larger numbers only to later discover that when you look at 8 Ohm, 20-20kHz ratings you suddenly find the numbers are much lower. So you have to look at the ratings that are relevant to your application, not just what numbers the manufacturer wants you to see. You also often have to look at what ratings are shown. For example, not every amp is rated for a 2 Ohm load in stereo or a 4 Ohm load in bridge mode. Once again, the only ratings that matter are ones that can or do apply to the situation.


So to put his all in perspective, let's look at you situation. The PRO 15 Mk II is rated at 300W continuous, 98dB/1W/1m sensitivity and a nominal 8 Ohms. The T-AMP TA1050 MK-X is rated 350W per channel into 8 Ohms, but looking at the other specs one can probably assume that is an EIA (1kHz, 1% THD) rating, so maybe 315W per channel full range. That is not a bad match, you won't want to push it too hard but 123dB at 1m is probably more than enough for the coffee house, small venue type applications apparently involved. You could go to a bigger amp with maybe a 500W to 600W per channel rating, but the difference would be 2-3dB. If it was a rock, hip hop, etc. application then the extra 2-3dB may be worth the extra investment but with your application, and since you can apparently get a deal on this amp, that is probably difficult to justify for you. The little 1622 FX mixer would probably be fine for the application noted, you might even find the internal effects useful. However, there are also a number of very similar amp and mixer products available from numerous manufacturers, although the availability and pricing of products can differ between the US and the UK and makes it more difficult to make specific suggestions.


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## pspdave (Jul 18, 2010)

aha.. another lesson learn't.. i feel i should be paying you for this amazing incite! 

Anyway, I have just purchased this power amp:
THE T.AMP TA2400 MK-X - U.K. International Cyberstore

I'm sure there are better an worrse ones out there, but looking at the specs, i think it will do nicely for what i need (heres hoping!!)


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