Forums Music Speaker Plans Any tips for a first system??

This topic contains 10 replies, has 6 voices, and was last updated by Avatar KJordy December 13, 2013 at 3:04 pm.

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  • #1055947
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    KJordy
    Participant

    Me and a couple of mateys are planning to start building a little system for a few shindigs nothing big just a little personal rig. Have minimal experience in all of this stuff atm but we’ve got some cabs being built for us now for cheap so we’re gonna go through with it. Any tips you boys could give us like what amps, suggest changes, anything that could spark a few ideas in our heads would be much appreciated!! 😉

    Atm we’re planning on two 21” Super scoopers, filled with some PD.2150’s. Couple of 15” HD’s with some Kappa 15lf’s and 2 mt102’s with some kappa pro10s for the mid drivers, some beyma cp800ti top drivers and some beyma td460’s for the horns.. Reckon this will sound nice?

    Haven’t a clue what kinda amps to look for or what not some suggestions would be much appreciated, but we’ll mostly only be doing small things maybe a couple of hall party linkups with a few other mateys we have that are building a rig.. Gonna be playing mostly hard trance, jump up, dark dnb, jungle, breakbeat, breakcore, prog and minimal.

    #1273726
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    Pat McDonald
    Participant

    Well, look for combined watts of the speakers, and don’t buy an amp that can make more watts than that… that way you will never blow up your speakers. Guaranteed.

    ON THE OTHER HAND, IF, and only IF, you are confident about having a limiter on the amps output, you could buy an amp that can produce more watts.

    Reason? Last 10% or so of a maximum output is where the amp starts distorting the sound. If you have a BIG amp that’s never turned up full, then you won’t overdrive it (although one accidental twist of the volume and your speakers could all go pop).

    I am far from expert in current amp technologies… but then I’m the sort of person that goes diving through a skip for materials so probably not best judge of new kit.

    #1273724
    Avatar
    cheeseweasel
    Participant

    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).

    #1273721
    Avatar
    General Lighting
    Moderator

    TBH if you are where I think you might be your main issue is not getting it confiscated rather than the technology.

    You can get your stack seized even at a hall party if you have breached the venues license, that happened to my friends a while back (the hall in question is barely a few miles from where I am working at present). A tip: be honest with the hall committee about the party, don’t bullshit them with fake details or over the scale of the event (They have all been told by the cops about the tricks used) if they refuse accept it and find another village hall, and take heed of any concerns raised about noise/environmental damage.

    it is however still possible to hold both hall parties and outdoor parties even in East Anglia and go home with your rig and freedom intact if you go about it the right way. you might have to make a few compromises but its way better than pouring lots of money into replacing kit that has been seized. (which often leads people into other illegal activities and more trouble).

    #1273729
    Avatar
    season.
    Participant

    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.

    #1273725
    Avatar
    cheeseweasel
    Participant

    Martin Audio badged Lab-Gruppen FP6400 going on ebay for cheap right now Martin Audio MA4.2S / Lab Gruppen FP6400 | eBay

    Really nice amp, and powerful!

    #1273722
    Avatar
    General Lighting
    Moderator

    @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)

    #1273727
    Avatar
    ROTTBULL
    Participant

    @kjordy 548064 wrote:

    Me and a couple of mateys are planning to start building a little system for a few shindigs nothing big just a little personal rig. Have minimal experience in all of this stuff atm but we’ve got some cabs being built for us now for cheap so we’re gonna go through with it. Any tips you boys could give us like what amps, suggest changes, anything that could spark a few ideas in our heads would be much appreciated!! 😉

    Atm we’re planning on two 21” Super scoopers, filled with some PD.2150’s. Couple of 15” HD’s with some Kappa 15lf’s and 2 mt102’s with some kappa pro10s for the mid drivers, some beyma cp800ti top drivers and some beyma td460’s for the horns.. Reckon this will sound nice?

    Haven’t a clue what kinda amps to look for or what not some suggestions would be much appreciated, but we’ll mostly only be doing small things maybe a couple of hall party linkups with a few other mateys we have that are building a rig.. Gonna be playing mostly hard trance, jump up, dark dnb, jungle, breakbeat, breakcore, prog and minimal.

    il te faudra un fitre actif et filtre ton scoop et hd15 .par exemple couper tes frequence comme ce ci scoop 50 to 80hz hd 15 80 to 150 or 200hz

    the t.racks DS 2/4 – Cyberstore France

    #1273730
    Avatar
    KJordy
    Participant

    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 🙂

    #1273728
    Avatar
    ROTTBULL
    Participant

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

    #1273723
    Avatar
    General Lighting
    Moderator

    @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).

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