Forums Music Speaker Plans install small hall speakers

This topic contains 20 replies, has 5 voices, and was last updated by Avatar Shadows March 26, 2013 at 11:44 pm.

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  • #1055168
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    Shadows
    Participant

    I’ll make 2 channel of 9 speakers each 8 ohms 50 watts each in series parallel with Resultant Impedance 8 ohms per channel the max continuous demand output per speaker is 10 watts with 15 watts PEAK from time to time Would like to know the following the power output of amplifier (per channel)

    #1267642
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    Clusterfrog
    Participant

    Yahoo answers is pretty good for this kinda thing

    #1267633
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    General Lighting
    Moderator

    if the speakers can genuinely handle 50W, then 400/500W per channel and lock down the controls / add a limiter so folk can’t grossly overpower the speakers.

    It is better to have more power in reserve than drive a smaller amp into clipping which will also destroy the speakers.

    Or rather than this complex series/parallel array, use a 100V system with individual transformers in speakers so you can set each speakers power demand as required.

    OK these speakers might be slightly more expensive per unit but you would save a few rupees in cabling, you can use “telephone cable CW1308 or similar”.

    I hope this is not your college homework question, as firstly you should be doing that yourself, and secondly if it is your prof hasn’t given the best description of the system!

    In any case the most info you can give helps. Most sound system advice here relates to transportable systems for indoor and outdoor music events in European countries where music with a strong sound and loud bass is preferred and the loudspeakers are usually upon the stage where DJ’s or performers also are situated.

    but from your description this might even be a general purpose system for a hall rather than simply for a loud discotheque type installation so it could be anything from a music concert to a talk by the local fishermen, and thus the loudspeakers are distributed throughout the hall rather than at one point. So cable losses would become significant, and the complex series/parallel set up could be miswired in many ways. But if you use 100V line then it is far simpler. you may also find that it is better to use mono than stereo.

    #1267639
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    cheeseweasel
    Participant

    This situation is what 100V line (constant-voltage) systems were made for, for the reasons GL stated (low transmission losses, ease of cabling, ability to add/remove speakers without screwing things up impedance/level-wise). Also the sort of amplifiers used for this purpose often have high-pass filters, limiters and clever safety features built in which protect the amplifier in the event of a short-circuit.

    A series-parallel network would work in your case, but as you can probably see, you will end up with a ‘grid’ of cabling to wire it all up – which may be fine if the speakers are in a shop ceiling, but a pain if they are strung out in a line or part of a temporary system, and with the disadvantage that a cable fault will likely knock out a few speakers and be awkward to trouble-shoot.

    If I understand your post correctly, your speakers are rated at 50W (is this RMS or peak? This is important) but you will only be putting 10-15W into them? How do you know this? Surely the more important thing is for the speakers to be loud enough, and the power consumed will be dependent upon this. Personally I would look at getting an amplifier that can comfortably drive the speakers to their full rated power (around 50W x 9 = 450W per channel). Bear in mind that if you are using very long cable runs in a low-impedance system, some of the amplifier power will go into heating the cables up, so you may need to compensate for this with a bit more power. If you are absolutely confident that the most power you will ever use per speaker is 15W then you could get away with a less powerful amp.

    #1267643
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    Shadows
    Participant

    Fantastic all of you, thanks much more for your valuable assistance.Am not an Student, am married and age 40, am just helping a religious association for this setup. Feel free to rectify any wrong method in the proposed setup. Let me give you some more data, the hall 15 x 15 meters x 3 height, the speakers fixed at 2.5 meters from floor, 18 speakers divided into 2 channel of 9 speakers each – 8 ohms 50 watts each NOT RMS – in series parallel : i.e. 8 X 3 = 24 / 3 = 8 Ohms with Resultant Impedance 8 ohms per channel and the max continuous demand output per speaker is 10 watts with 15 watts PEAK from time to time – Wiring 50/0.25 mm PER CHANNEL from amp output to the beginning of each start point of speakers thence with 30/0.25 to other speakers.Amplifier 450 watts X 2 channel, What is the lesser watts output ?. For 100 v line we certainly make it in few months. Speakers will be installed surrounding four central concrete columns…What can I do about echo, can I split some of speakers in the perimeters inside the building to eliminate echo ? The installation will start in one month time. Thanks for times spending just to help other.

    #1267640
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    cheeseweasel
    Participant

    Do you have any more info on the speakers? E.g. what is the make/model? There are various ways to measure the ‘wattage’ of a speaker. There’s ‘RMS’, then ‘peak’ (usually around 3x the RMS value) and the slightly ambiguous ‘program power’ (which varies from manufacturer to manufacturer).

    If you are only going to put 15W peak into each speaker (and you’re really really sure about this?), then you could get away with an amplifier of (15 x 9 = 135W), plus a bit extra to compensate for cable loss (this will depend on the total length of your cabling). So maybe 200W per channel? But you would need to make sure that the amplifier isn’t run into clipping, because as GL mentioned, an underpowered amplifier producing a clipped signal is likely to damage your speakers. I would personally not skimp on the amp and buy one that can get the most out of the speakers, but I guess budget is a concern here?

    With regards to echo…

    I don’t know what sort of space you are trying to cover, but in the UK we have a lot of old, stone churches that are very reverberant (and lots of old, deaf people that tend to go to them). Putting a pair of speakers at the front (like a rock gig) doesn’t work in these spaces because by the time you’re more than a few metres away from the speakers you are mostly hearing the reverberant sound from the room, which makes it very difficult to decipher what the vicar is saying. The key to getting intelligibility of speech in a reverberant space is to have a large number of small speakers distributed evenly around the room. The aim is to get everyone sat as near to a speaker as possible. That way everyone is getting a good ratio of direct-to-reverberant sound ratio and none of the speakers are so loud as to send lots of reverb bouncing around. So bear this in mind when you’re deciding where to place your speakers, as there is no electronic gadgetry that can compensate for room reverb (although acoustic treatment of the room may be an option for you).

    #1267634
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    General Lighting
    Moderator

    In this case I would have a meeting with your association and try and get them to fund the 100V equipment right from the start. As that way you could get a 300W 100V line output amp, rather than use the more expensive cable you can use the cheaper cable used for telephones or smaller speakers, and the speakers with transformers and the volume control tappings.

    in the UK we have a company called CPC / Farnell (it might be called Element 14 in your country or one near you) which sells lots of affordable PA kit, and many of the loudspeakers are good for both speech and music.

    That way you can use this to move some speakers to the corner and also adjust the levels of these, avoiding the echo problems and giving you leeway to relocate things if they are not quite in the “right place”. my extended family come from Malaysia which is a multicultural, multi faith society (and also makes a lot of electronic equipment) and the current best practice there is to use a “Western” approach to sound systems in all places of worship and go for best sound quality for both speech and music.

    #1267644
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    Shadows
    Participant

    Yes, again thanks everybody, Am so happy about your valuable instructions, I’ll follow up all your indications.
    Am NOT a highly qualified Electrician/Technician but your genuine Technics are most helpful…
    All connections will be made be myself because the association has nobody to manage the system.
    ECHO: 15 X 15 meters X 3 meters Height…Thanks for echo defendant based on some perimeter speakers perhaps some curtains too.
    Now, if am not abuse your time, could you see how I can install a second amplifier from PRE-AMP of master amp, to drive two speakers on stage as return ! I know it’s a problem but I would like to set this, OF COURE, following your instructions once more…

    ANSWERS to your Questions:-
    I got two choices of speakers:-
    FIRST type 8 ohms 50 watts MAKE Rayden YD 103 and
    SECOND type 4- 8 ohms 50-100 watts.MAKE Rayden R 103 Japan..
    .
    Also several choices for amplifiers
    FIRST amp HI-Fi Sansui 150 watts Stereo and
    SECOND Malanshi Hi-Fi Model OK 05 500 watts
    THIRD Piasing HI-FI 150watts 2 channel and
    FOURTH Ahuja PA 300 watts 2 channel and
    FIFTH Amplifier PA 100 watts 2 channels:- TZA2000 and
    SIXTH AMPLIFIER/Preamp: InterM PA6000 Rated Output (RMS) 240W 2 channel…

    FEEL FREE TO RECTIFY ANY ITEMS.
    Thanks and regards

    #1267635
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    General Lighting
    Moderator

    For amplifiers you really should get a professional amp rather than use the “hi fi” amps. The hi fi amps are made to listen to music in your house and not always as robust as the PA amplifiers.

    The inter -m is a good one as it would work with either low impedance loudspeakers or 100V. Also it has the phono line output so you can have your second amp and two speakers on the stage (which will need independent volume control to avoid feedback).

    Inter-M PA-6000A Amplifier

    I could not find any info on the speakers. bear in mind you can buy the 100V transformers separately and build them into the speaker cabinets.

    Do you have suppliers of this equipment locally, or will you have to import it from another country?

    I believe Mauritius is hot, so you will need one with good fans/ventilation and that will not generate excessive heat when switched on for a long period.

    Is the electricity supply in the hall good and reliable? does it have airconditioning and other big appliances connected to it? (you have to be careful of these as they can put unwanted noise into your sound system).

    #1267645
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    Shadows
    Participant

    Hi General Lighting,
    In the coming months, I’ll not miss to call attention for your paragraph one and three in thread 7 about electronic equipment. At this time we try to stick to series/para system, Hope no smoke at view point ! You know am confident if I follow your group instructions that will go.

    Thanks for echo defendant solutions

    #1267647
    Avatar
    Shadows
    Participant

    General Lighting

    Your Para 1: What is it If we use for this session an Hi-Fi amp and in few month we choice an PRO amp PA with 100v ?
    Your Para 2: I didn’t knew that the PHONO output can be used as pre-amp, So good ! I’ll keep in mind PA-6000A amp.
    Your Para 3: I got two choices of speakers:-
    FIRST type 8 ohms 50 watts MAKE Rayden YD 103 and
    SECOND type 4- 8 ohms 50-100 watts.MAKE Rayden R 103 Japan
    Yes for seperate transfo, I’ll be back soon.

    Your Para 4: Once we work out the need for 100v line system, I’ll be back for your assistance, for sure !
    May be import from another country,

    Your Para 5: Already have a local fan, thanks for reminder….The system will stay on from 9 to 16hr for three days.
    Your Para 6: Electricity study 220 volts can be interupt without notice from electrical company !
    I prepare to insert a UPS in circuit just as standby, with additional batteries in stock !!
    No Air Cond. just 4 ceiling fans and Fluo. lighting
    What do you think about capacitor on mains 220v just to reduce incoming noise ?

    How you checked Thread 5 for size of wire:- 50/0.25mm X 25 meters from amp output to a group speakers extended with 30/0.25 to last speaker in this group which length is 11meters. Repeat same for the second channel.
    With these size of wire I try to keep the load as 8 ohms as possible. Thus avoiding volt drop, I suppose !

    #1267648
    Avatar
    Shadows
    Participant

    Your Para 1: I got two choices of speakers:-
    FIRST type 8 ohms 50 watts MAKE Rayden YD 103 and
    SECOND type 4- 8 ohms 50-100 watts.MAKE Rayden R 103 Japan
    Your Para 2: Am sure for 15W peak per Sp. But as your indication to make 200W or 300W.
    Your Para 3: ECHO- Sixe of Room 15 X 15meters X 3 Height. Yes exactly as you said for two major speaker in front of assistance is not a good idea…The speakers will be at 2.5meters from floor…Yes I’ll group assistance surrounding the four central concrete columns just as you said in the vicinity of speakers…We always annouce to keep electronic gadgets OFF during sessions, thanks for these reminders…

    #1267636
    Avatar
    General Lighting
    Moderator

    @shadows 527263 wrote:

    General Lighting

    Your Para 1: What is it If we use for this session an Hi-Fi amp and in few month we choice an PRO amp PA with 100v ?

    [/quote]

    you might be able to do this for a smaller scale system (perhaps with less speakers), but must be careful the amp is not made to produce too much power/gets too hot. Often there is not much price difference between a hi fi amp and a smaller PA amp anyway.

    Also you need to bear in mind what the sound sources will be. Usually with religious services there are one or more microphones, and perhaps recorded sound from another source, often these are used together. so you will need an amplifier with a mixer section. hence the PA-6000 amp would be ideal as it has this built in. If your religious leaders are not sound engineers they could find other equipment too difficult to use, whereas a hi fi amp even with microphone inputs (many Asian ones have these as karaoke is popular) might not have enough mic inputs, and they will be “unbalanced” and thus will let noise in.

    Your Para 2: I didn’t knew that the PHONO output can be used as pre-amp, So good ! I’ll keep in mind PA-6000A amp.

    be careful here that “phono” is a term used for the type of connector (RCA connector is another word of it) but also a type of input (for gramophone turntables). what you want from an amplifier is a “Line Output” or “Record Output” which is the output of the pre amp.

    Your Para 3: I got two choices of speakers:-
    FIRST type 8 ohms 50 watts MAKE Rayden YD 103 and
    SECOND type 4- 8 ohms 50-100 watts.MAKE Rayden R 103 Japan
    Yes for seperate transfo, I’ll be back soon.

    The only Rayden loudspeakers I could find from Japan are the sort sold for motor cars. Do they come in enclosures, or will a local carpenter be building them?

    Your Para 5: Already have a local fan, thanks for reminder….The system will stay on from 9 to 16hr for three days.
    Your Para 6: Electricity study 220 volts can be interupt without notice from electrical company !
    I prepare to insert a UPS in circuit just as standby, with additional batteries in stock !!
    No Air Cond. just 4 ceiling fans and Fluo. lighting
    What do you think about capacitor on mains 220v just to reduce incoming noise ?

    most modern sound equipment already contains the capacitor. Putting another extra mains filter in the supply needs to be done properly by a qualified electrician or it can be very dangerous, as if miswired it will make all the metal of the equipment alive to the mains electricity.

    Quote:
    How you checked Thread 5 for size of wire:- 50/0.25mm X 25 meters from amp output to a group speakers extended with 30/0.25 to last speaker in this group which length is 11meters. Repeat same for the second channel.
    With these size of wire I try to keep the load as 8 ohms as possible. Thus avoiding volt drop, I suppose !

    You should get away with this but as cheeseweasel said be careful about the wiring. (also make sure that it and any junction boxes used cannot be confused with 220V wiring for the building!)

    #1267649
    Avatar
    Shadows
    Participant

    Hi General Lighting

    Our Para 1; 100v = Definitely, near future w’ll go on PA amp.
    Yes, 5 Microphone,
    Spiritual music 5 x 3min per day but NOT used at the
    same time with microphone.

    Our Para 2: Ok for pre-amp output.

    Our Para 3: Speakers purchased WITHOUT enclosure, Now under
    preparation with carpenter.

    Our Para 5 – 6: Ok, anyway we just received a voltage stabilizer with .
    filter for our equipment.

    WIRING: All wiring will be fixed/weld/clipped (by myself) directly to
    speakers in their casing, no visible junction, except
    the end to connect to amplifier output. I’ll make the wiring
    this way just to avoid any connection on site, just hang
    the wires, speaker’s casing, to “hooks” already fixed
    on site. Nylon string provided between speaker’s casing as
    prevention mis-handling or stretching of wires.

    NOTE= This is not a permanent installation, next session in
    6 months time. We are waiting for a new building and I
    propose to do all technical section a concealed installation.
    Thence 100v system will be selected.

    #1267637
    Avatar
    General Lighting
    Moderator

    That looks like it should do the job for your organisation. it is very similar to the old British way of setting up sound systems in temporary structures especially church halls, youth clubs etc. In most faith groups (and even at Western style rave parties held in outdoors) it is commonplace to collect donations for the upkeep of a sound system at the gatherings…..

    Make sure your voltage stabiliser is connected correctly to the mains protective earth for your building, and that this earth is good and robust throughout the building (any exposed metal in the building must be connected to it). This could be a metal spike sunk deep into the ground, or the metal outer covering of the electricity cable. Your electric power company should be able to tell you this, or the electricans who wired up your hall. (in most countries such installations must be tested for safety every 5 years and notes kept of this).

    I forgot to say add that I do use a UPS on my home system as even though the UK is supposed to be a developed Western country, global energy shortages and market fluctuations mean that the voltage (supposedly 230V) can vary wildly especially over weekends, and power cuts for a few seconds are common. This is enough to cause many problems with computers and other digital electronics. Originally I bought the UPS for my computers and a telephone exchange and IP network equipment that is in the bottom stairwell of my house (so I can work from home) but I found it made the sound quality of my audio equipment better by isolating the mains power from other surges, sags and noise. if your local electricity supply is very intermittent and you expect to be using UPS battery power quite often, a pure sine wave inverter in the UPS is desirable as that means there will be better quality power when you have to use the UPS for your main power source.

    #1267650
    Avatar
    Shadows
    Participant

    This session will be held in a Public Hall converted on this occasion to serve our meeting…Perhaps in near future w’ll have our location.
    Ok for earthing, I had a earth megger test with a result of 1.2 ohms. I already prepared accessories for a bonding of some items. Thanks for reminder…
    Tell me please: from amp output to first group of speakers, I have 24 meters, you think I should absolutely increase the size of wires to maintained the load at 8 ohms OR it could be a bit more say 9 -10ohms ?

    #1267651
    Avatar
    Shadows
    Participant

    According to discussed load (18 speakers – ± 15watts each) kindly help me select a choice between these amplifier
    AMPLIFIER/Preamp: InterM PA6000 Rated Output (RMS) 240W
    Amp/Preamp – Ahuja – MXA3500 350W RMS at 10% THD
    Amp/Preamp – Ahuja TZA4000 – 200 x 200watts
    Amplifier 2 channels 100 X 100 WATTS:- TZA2000 –

    #1267638
    Avatar
    General Lighting
    Moderator

    @shadows 527942 wrote:

    This session will be held in a Public Hall converted on this occasion to serve our meeting…Perhaps in near future w’ll have our location.
    Ok for earthing, I had a earth megger test with a result of 1.2 ohms. I already prepared accessories for a bonding of some items. Thanks for reminder…
    Tell me please: from amp output to first group of speakers, I have 24 meters, you think I should absolutely increase the size of wires to maintained the load at 8 ohms OR it could be a bit more say 9 -10ohms ?

    if your impedance in the wires goes up it will not harm the amplifier. but the power will be going into heating up the wire, rather than making sound.

    The AHUJA amps are not as common here in Europe but look like they are based on an old British design but (hopefully) with components more suited for the hot weather. They appear to be popular for installations in India (where they are made).

    #1267652
    Avatar
    Shadows
    Participant

    QUOTE if your local electricity supply is very intermittent and you expect to be using UPS battery power quite often, a pure sine wave inverter in the UPS is desirable as that means there will be better quality power when you have to use the UPS for your main power source.QUOTE

    Thanks for all and your inestimable time you spent with query. I think our UPS will be fine. I let you know after conference…Thanks

    #1267632
    Avatar
    Anonymous

    Sorry to jumping in on someone else’s thread but what’s the best configuration for hall speakers?

    #1267641
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    DaftFader
    Participant

    @johnjamesss 536414 wrote:

    Sorry to jumping in on someone else’s thread but what’s the best configuration for hall speakers?

    Depends on the hall size/shape, how loud the speakers are etc.

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