Have a read of Noname’s excellent guide to building a soundsystem in the sound engineering forum.

http://www.partyviberadio.com/forums/sound-engineering/27792-how-build-sound-system.html

And having a limiter before every amplifier is pretty essential if you don’t want to cook your speakers. You’ll need an active crossover like this http://www.amazon.co.uk/Pulse-Lsm216-Loudspeaker-Management-Crossover/dp/B00A49ZLF6 to split the left/right outputs from your mixer into the correct frequency bands for each speaker.

For anyone interested in setting up system limiters…

To calculate the limit point for each output, you need to consider the rated RMS power of each speaker and the voltage gain of the amplifier driving it. The aim is to limit the signal into the amplifier at the point when it is outputting the maximum power the speaker can take.

So let’s say you have a bass bin of impedance 8 ohms that is rated at 1000W RMS, and you are using an amplifier capable of outputting 2000W into an 8 ohm load. On the amplifier’s spec sheet it tells you that the input sensitivity if 1.2V. This means that if you put 1.2V into the amp (around 3.8dBu) you will get the maximum voltage out of the amplifier – putting more than 1.2V into the amp will cause clipping.

If we find out the voltage gain of the amplifier, we can calculate the input level that will result in the amp producing 1000W into 8R. This will be the point we want to limit at…

– We know that if we put 1.2V in, we get 2000W out at 8 ohms.
– Using P=(V^2)/R we can see that this corresponds to an output voltage of sqrt(2000 x 8) = 126.49V
– Formula for dB gain = 20log(V2/V1) = 20log(126.49/1.2) = gain of amplifier = 40.46dB
– 1000W at 8 ohms = sqrt(1000 x 8) = 89.44V

So if the gain of the amplifier is 40.46dB, and we want an output of 89.44V, what must the input voltage be?

40.46 = 20log(89.44/x)
10^2.023 = 89.44/x
x = 0.85V

Converting to dBu, 0.85V = 20log(0.85/0.775) = 0.8dBu

So you’d need to set the limiter at 0.8dBu (or more likely 1dBu, as most processors work in 1dBu increments). I don’t bother doing all the maths every time – there are a couple of really useful tools for calculating dB gain and dBu/dBV conversion here…

– dB calculator for amplification gain and damping (loss) factor of an audio amplifier calculation decibel dB ratio – sengpielaudio Sengpiel Berlin
– dB dBu dBFS digital audio dBV to volts conversion – calculator volt volts to dBu and dBV dB mW SPL dB decibels – convert dB volt normal decibels relatioship relation absolute level convertor converter decibel to dbfs converter calculation online atte

Alternately, use the limiter calculator at the bottom of the page on the Funktion One website that does it all for you!

Note that if you are using an amplifier that is not powerful enough to deliver the driver’s maximum rated power then you will need to set the limiter to be the same as the amp’s input sensitivity to prevent clipping (as an underpowered amp being driven into clipping is a dangerous thing and will toast drivers pretty quickly).

Hall parties are a great way for a new rig to get the ball rolling and get your name out there IF as GL said you follow the rules and be honest with the hall committee. Another important point is to not over publicise the event. I’ve attended and helped out at hall parties that are WAY over crowded (there isn’t any security team and the rig owners wanted the most amount of money they could get) which A. will cause an issue with the feds (if they’re 50+ cars parked outside the hall car park and along the street this will cause issues with the locals too) and B. Can be dangerous and will most likely result in the feds turning up and restrictions on hall parties for other systems in the area. Just follow the rules. Whether it be the number of people allowed to attend or the sound restrictions/finishing times. Hall parties in my area (Suffolk) almost always end at 12:00.

All the drivers and cabs you listed are all very nice. Should sound lovely. Would be interested to see them 21″ super scoops, i haven’t seen many rigs my ways running those. Where are you located out of interest?

Amps wise the Behringer EP1500 and INUKE series are very nice. It all depends on your budget but the berry’s are very good value for money and reliable. Peavy’s higher end amps are good as well but they can be expensive.

@season. 548118 wrote:

Hall parties are a great way for a new rig to get the ball rolling and get your name out there IF as GL said you follow the rules and be honest with the hall committee. Another important point is to not over publicise the event. I’ve attended and helped out at hall parties that are WAY over crowded (there isn’t any security team and the rig owners wanted the most amount of money they could get) which A. will cause an issue with the feds (if they’re 50+ cars parked outside the hall car park and along the street this will cause issues with the locals too) and B. Can be dangerous and will most likely result in the feds turning up and restrictions on hall parties for other systems in the area. Just follow the rules. Whether it be the number of people allowed to attend or the sound restrictions/finishing times. Hall parties in my area (Suffolk) almost always end at 12:00.

Many folk do not realise that even at a private house party the organisers have a legal obligation to “keep the peace” which dates back to ancient times (this doesn’t mean they must be totally silent but must not annoy or harm others) and they have civil obligations for everyones safety. I am aware of Court cases where posh middle class families have had a house party and someone gets badly injured and the families end up suing one another in civil court (which has a lower burden of proof than criminal law) – which is why for public events there are all the licensing arrangements and rules.

You can usually look on the local authority website or contact their licensing team and they will tell you the exact arrangements for each venue. Babergh’s website is particularly good in this respect, you can see details of every premises in the borough.

BTW the old folk who live in these villages and grew up there are not all killjoys and nimbys. I was discussing this with some on a electronics forum where everyones a bit older, and they were themselves having hall parties in the days when they needed to take 5 different kind of mains plug along and check the local voltage (anything from 200-250 volts and either AC or DC) and that the EL84 valves in the output stage of the amplifier were not shaken loose (usually a spring loaded clip kept them in the sockets but this could come adrift), and some records were still played at 78 rpm :laugh_at:

also they often are genuinely woried about safety as back in the day some of their friends might have got drunk or done too much drugs and OD’d or crashed their car and were hurt/killed, or they lost their mate because he got sparked from a sound system with dodgy earth connection (especially live band players often got killed this way as 250V turned up on the metal frame of a guitar or microphone)

@KJordy 559264 wrote:

Bringing this thread back from the dead, sorry haven’t been online since I posted this. I’m from Bury St Edmunds in Suffolk mate!

Oh and for those who are interested, we’re just about up and running. 2 18” Hog scoops in the process of being built, 2 15” W bins, 2 HD215s and 2 Cerwin Vega T-250 tops. Running off 2 CV-2800s at the moment, using an ultradrive as the xover. Cheers for the advice lads 🙂

@ROTTBULL 559462 wrote:

if I’m not mistaken Wbin and hd215 work on the same range, which can induce depression in the frequency

yes, what can happen (though it initially does not seem logical) is the two bass units “fight” each other. This can get worse if any of the loudspeaker units are accidentally wired out of phase with the others.

I would suggest that KJordy and his friends search out a place where they have permission to be, that is large enough to house the rig, and has a good reliable mains electricity supply from Uk Power Networks. Around this time of year, barns are often empty across Northern Europe, and it is not illegal to test a sound system inside one provided the owners have given permission and it is not causing nuisance to anyone else. Above a certain number of people it would become a licensable event, but below 20 the most that can happen is a bobby might ask the owner what is going on and just say to all “remember to get a TENS when you do your event”.

Also its worth spending about £50 on a sound level meter and a mains power meter. Two important things are remembering you need to put slightly more electricity in to get the same power of audio, and that you want it to be good and loud in your target area, but not 0.5km away in other villages or even outside your venue. The very fact you have even thought about these things is likely to make council types realise you
have a few brain cells in your heads and can keep folk safe.

Also by testing the kit before a big event you learn better how it sounds and how the bits work – the active crossover you have isn’t the simplest piece of kit to work out and though it has pretty lights, if you set it up wrong your rig will actually sound rough.

BTW European youths do not have it any easier than any of us with regard to putting on events – its just that they are more articulate about putting their case forward to allow them (trying to fight the cops does not end well, they have guns to hand all the time rather than separate special armed units. Although nowadays they do not like shooting at civillians indiscriminately and can still get in trouble for doing so, there have been occasions in my lifetime where cops have discharged live rounds into mostly unarmed crowds in mainland Europe.

However I recently heard an old boy from round here talking on the amateur radio frequencies, who was openly chatting about how he had set up a mini rig in his own barn (and some lights too) he thought he would set it up for the benefit of his grandchildren and sometimes used it himself in daytime, as he could listen to progressive rock loud but in the end had to somewhat reluctantly dismantle it as he knew that eventually half of Suffolk’s youth would turn up and he would get in trouble personally for behaving like that at his age – plus the pigs would come in soon. (not those pigs, his own, but there are restrictions on what kind of music you can play to pigs due to animal welfare laws – Radio 3 and 4 is fine but hardstyle is too much for them).