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Speaker Design


jony*5

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I want to build my own budget PA system for a number of reasons:

 

I like DIY

I Love good music played through quality sound reproduction

I cant afford a d&B / l'acoustic / meyer / martin rig.

I'm an electrical engineer with a good understanding of audio and mathematics.

 

 

What I've thought about doing is making a 4/5 way system.

 

1> (super high)/High/Mid 2> Bass 3> Sub Bass

 

1) medium throw horn loaded 10's or 12's with 2" comp (2 a side)

2) 2*15 reflex bass (1 a side)

3) single 18 bandpass (2 a side) very narrow frequency of 30-80hz +/-1db

 

The idea is to give as wide a flat bandwidth as possible (I love sub 25-50Hz), but I hate 50-100hz boom boxes.

 

 

Has anyone done anything like this before? any tips?

Do I need 2" comp or will 1" do?

Folded bass horns- they're not in fassion / or they're no good???

10's or 12's ????

Will I appreciate 30Hz from an 8kW system???

Would I do better with 2*18 reflex instead of 2x 18 bandpass???

 

Drivers RCF/FANE/PD/CELESTION/BEYMER/EMINENCE

I'm thinking of fane colosus 18600XB's, rcf 551k 15's, Eminence Kappa pro 10/12's, any suggestion's for HF?? We're thinking budget here, £120 max per driver...... do you want to challenge me on my choice... please !!!

 

please post replies, this is going to be a big spash out for a little hobby!!!

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If you haven't got it get hold of the Fane/Eminance enclosure design book, all the hard maths already done for you.

 

also, an old post from one of the newsgoups...

http://www.beyma.com/

Click on English- unless you want the Spanish site.

Click "products"

 

On the upper right is an icon titled Enclosure designs- kinda small you will

have to look for it. Contains about 40 designs from subs to traps to wedges.

Best of all it's free from the good folks at Beyma. Covers bass reflex, band

pass and a  double 18"folded horn. They make damn good speakers to put in

them BTW.

 

and also www.speakerplans.com

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Ah the black art of speaker building.As well as the eminace book, the loudspeaker design cookbook is worth a look(get it from the library if your on a tight budget),also winisd ( http://www.linearteam.dk/)makes the design procces a bit simpler.There both realy aimed at hifi but the theory still works for pa cabs

How do you intend crossing over? active or passive

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hmmmm, what are the benefits of a super high tweeter other than increased sound stage? I thought these were only ever any good with sacd because of the increased bit rate or something like that which opens the freq max from about 21k to about 50k.

 

anyway...

 

...me and my colleague are also planning to custom build a system, mainly subs, built under the stage to output through vents into the lower part of the flooring, where the real "stage" is when performances are held.

 

has anyone got any ideas for drivers. they must be relatively powerfull, our current system (1.2k), gets comnpletely lost in the hall which is a 60's/70's design. lots of reflections from the higher frequencies, there is absolutely no bass, almost as though we didnt have the bass/sub drivers!

 

can anyone help?

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  • 3 weeks later...

a company in bournmouth has recommended p.audio drivers for subs (and all other drivers/comp.)

 

They say they're better than fane/eminence, and very comparable with pd, ev, rcf and beyma.

 

 

Anyone any comments???

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  • 2 weeks later...

Jony,

 

You don't say why you want a PA system - is it for disco, pub bands, theatre, corporate, hire out to mates?? The eventual use this will define what sort of system you need to be thinking about building. Also, consider the practicalities - do you have space to store it, do you have space to cut up 8 x 4 sheets of ply, what you're going to cart it around in? Clearly no point in building LAB subs if you've only got an average sized estate car because they simply won't fit in!

 

Also do you have a rack of decent amps already? If you're thinking about a four-way system, you'll need at least 2 grands worth of amplifiers to drive it all with - that's secondhand prices as well!

 

If you're just starting out and want a general purpose PA that you can start to make money from, what about a couple of 12" + 1" mid-top boxes plus a couple of single 18" subs, either direct radiating or bandbass. With the right drivers and some meaty amps, a system like that will handle most small to medium sized pub/hotel venues

 

Anyway, once you've got your objectives clear there are plenty of places to buy really good (Precision Devices, PHL, B&C RCF etc) drivers from, at under the maximum price you suggest. As for box designs, take a look at Speakerplans.com

 

Mail me off list if you need box design software, further supply suggestions etc.

 

Good luck,

 

Pete.

 

Rog Mogale's Speaker Plans Site

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  • 4 weeks later...

Sounds over complicated, why not just use a good 2 way system. you can

always just use the tops off the subs on the own if there a decent size.

The more there is to adjust the more you will adjust, go round in circles.

 

I'll got a pair of scoops loaded with 15" fane colosuss, driving the pair

at 1500watts @ 4ohm, good clean bass as well, cross them over right

(my x over set at 200hz) and can get a real tight sounding bass equal

that of 4 reflex 15" cabs but with half the amp power needed, cheeper bass.

it's just the size that lets them down, light but large.

 

Have you looked at the CELESTION drivers, 600 RMS but alittle cheeper,

there in the cpc catulogue. (computer spares catulogue)

 

Don't skimp on the power for the tops either, I'm finding out the hard

way, you need allot of power to get the higher volumes.

 

This may sound stupid, but try and alway buy amps that will bridge up

and go down to 4ohms, easy way to add power from 2 channel to 2 bridged

amps, just buy another amp the same, cheaper than buy a bigger 2 chan amp.

 

hope that helps any. :wub:

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sorry to go on, but I dout u'll get 18" fanes for that money (unless u've

already priced them up) I pay'd £100 each from mine and that was a favour

from Mr fane him self as I worked for Solid State Logic at the time.

 

Also if you are doing it on a budged, have u desided what amps u want 2 use,

there are loads out there, but if cash is tight take a look at the new

BEHRINGER range of EUROPOWERS there's a new one about to be released,

EUROPOWER 2500, the reviews on the 1500 sound quite good and all the

behringer stuff I've brought is spot on, real value for money. Anyways there's

a site called: www.bonza.co.uk he'll do this amp (when release very soon)

for £280 and the 1500 for £230, that's a lot of amp for the money, check the

specs: www.behringer.com

 

He's also got some very good second hand stuff.

 

Another little site on scoops and w bins: no plans but tells u alittle bit

about them.

 

www.maryland-wireless.com/users/soundpro/PA.html

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