Hi, I need help with renting audio equipment(a full karaoke system ). What are the factors(both electrical and other parameters) that we need to consider while renting an equipment?
I can't find any detailed guide on this anywhere on the internet(only found some generic guides and are promotional). Apart from power ratings like RMS do we need to consider anything else for renting a sound system?

(Moderator's note: Apparent promotional link has been removed -dc)

 

Hi, I need help with renting audio equipment(a full karaoke system ). What are the factors(both electrical and other parameters) that we need to consider while renting an equipment?
I can't find any detailed guide on this anywhere on the internet(only found some generic guides and are promotional). Apart from power ratings like RMS do we need to consider anything else for renting a sound system?
This guide from a company named freeman is having some generic tips for this. I need some technical stuff. Please help me?

Hi Boris, do you work at Freeman? This seems more like an attempt to cross post your website than to really ask a question. Especially since your "question" is so vague.

 

Hi Gopher, It seems that you misunderstood my intention and I am sorry to hear this. I worked at AT&T ConnecTech and is now a free bird.
You referred my question as "vague", Could you please explain that?
I found that RMS and PMPO are used to define the power output of a sound system and PMPO is used to fool people as it is a senseless parameter(FIY).
Above all, I asked this question here to get clarification on these two terms (RMS and pmpo) while renting an equipment. If you google and find a good article like freeman, Please share it, I am happy to see it
Cheers
BD

 

I am no expert in sound systems but I agree that RMS output appears to be the only meaningful way of rating the power of an amplifier.

How much power do you need? That depends on the number of people in attendance (bodies absorb sound), the size of the room and more importantly the acoustics of the room. I have been in town halls and sanctuaries not designed for artificial sound amplification. Adding power amplifiers makes audibility worse because of echo from the ceiling and walls.

The other thing to note is that the perception of sound is logarithmic. This means that power increase is exponential for equal increase of perceived loudness. A 30W amp might be just adequate for small rooms. As you increase the size of the room you have to move up to 100W then to 300W.

For audibility in difficult situations, extra power may not be the right solution. There is a well known sound systems manufacturer that utilizes a pair of line-array speakers that can project the high frequency sounds more effectively when properly mounted on speaker stands. A single low frequency driver sits on the floor to cover the bass side of things.

The biggest problem with live mics is how to avoid acoustic feedback. Placement of the speakers and mics is critical. Adjusting the tone and levels on the mixer and amp can also help to prevent feedback. The important thing is to position the mics behind and far away from the speakers. You don't want speakers to be facing the mics.

For vocals, as in a karaoke system, it is important to have a monitor. This is a speaker that faces the singer. The amp must have a separate monitor output and level control. This is important so that the singers can hear themselves.

For proper karaoke setup, you should have multiple screens, one screen for the audience and another for the singers. You want singers on stage facing the audience.

On the rental question, in TO, L & M should be able to answer your questions and supply your needs.

I hope I have been able to provide you with sound advice.

 

Also, look at the AC input power rating. It gives the actual (theoretical max) power a unit takes in. That means, the output power will be something less. This is important because you will often find receivers and studio amplifiers rated at 150W per channel or more with 2 channels (Stereo) output (suggesting 300 watts of total output) and then you look at the AC rating at the input (usually by the power cord) and you'll see something like 1 amps at 120 volts AC which means a maximum output of 240 watts. The story generally gets worse for 4 and 6-channel receivers.

Also, make sure the speakers are matched to the output of the receiver (8 ohms, 4 ohms or 2 ohms) to meet power matched.

 

I used to do DJ work with my brother for a few years and to be honest it all depends on what you are doing. If it's just voice work in a 1000 or so square foot room a few hundred watts on some good quality speakers at or just above typical audience ear height is more than enough.

But if you're working heavy dance music and loud in the same area if you don't have several kilowatts at the speakers (big powerful efficient speakers) you will sound like crap and that's just for indoor work. For outdoor work like street dances we would rig up all their of the three main portable shows sound gear, plus borrowed more, and start pushing into the 10 - 12,000+ watt range if we had a power source capable of handling it. That was okay at that point.

So depending on what exactly you want to do and where you want to do it a few hundred watts to 10,000+ is the power levels and proportionately sized speaker system you will be needing.