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nicksmurf 15th February 2004 07:20 PM

Designing PA speakers
 
I already have some Electrovoice speakers and like their quality and efficiency. I'm planning to open a coffee house/concert club soon and want to start designing my PA.

What do you think about using EVM-15B for the LF, EVM-12L for the mid bass-mids? What should I use for tweeters? Would it be horrible if I just put 3 cheep motarola tweeters in each cab? Or should I invest in better horns?

Should I horn load the EVM-15B or just put it in a ported box? If it would be in a ported box, they are really really small from what I've seen reccomended. I have one in a small box (less than 2^2 feet) right now and it works rather well.

The EVM-12L would probably be ported to keep the excursion lower. (the speaker actually has an extreemly flat response)

I would probably run 300-400 watts to the subs and the same to the mids and highs. It would be bi-amped. I'm looking for sound quality and decent volume. I do not want to be clipping the highs like many clubs do!

dooper 15th February 2004 08:18 PM

Live or recorded music? What style(s)? How many seats in the club?

Sounds seriously underpowered to me, unless the place is 50 seats or less, and you plan on booking acoustic acts.

JMO,

dooper

sek 15th February 2004 09:01 PM

Hi,

Quote:

Would it be horrible if I just put 3 cheep motarola tweeters in each cab?
Yes, definitely.

Quote:

I'm looking for sound quality and decent volume.
And that's a reason for you to go for something professional. Not that I think you're unable to DIY it. But as you say you're going to start a business there, you probably want to save some money by leasing reasonable gear. Instead, you would have to buy dozens of speakers (incl. woofers, midranges and drivers/horns).

Quote:

I'm planning to open a coffee house/concert club soon...
People expect higher quality (for their money) than they used to a couple of years ago. I (in particular) am always impressed by how much design effort the good professional PA manufacturers invest in their designs.

Don't get me wrong Nicksmurf, I really, really, really don't want to set you off. But planing "a coffee house/concert club soon" and starting a PA design from scratch - with a couple of EV-chassis, no tweeters and no horns at hand - don't go together very well.

You could hire your gear on demand for the first couple of weeks or months and determine what (average and maximum) SPL you need, how many speakers are neccessary for good sound dispersion and what type (and number) of bass boxes fits your room acoustics.

Hope this helps.

Sebastian.

dalbjerg 15th February 2004 10:03 PM

First of all!! English is not my 1'st choice of languish, so please do not judge me on the (bad) spelling and grammar.
Itís right that for a full scale PA 2*300 to subís and 2*300w to mid/top are not much. But if the place you plan to open are of that kind where you normally have small local gigís and occasionally (weekendís and so) hire a more professional band, it will cost you an lot of moony to have a small setup hired for the normal stuff (local gigs and so).
I think you could design a pretty good set up for those event whit your EVís and then only hire PA system for the bigger event. Many of those bands can often be hired for a little more dollars and they will bring in there own PA and sound techs.
I suggest that you design your tops , so you can hang them over the scene. Aiming towards the public. Place your sub on the floor and keep them in a ported box. Small bas horn has an awful ďHonkĒ sound. This kind of setup are used I several places and for the normal gigs its loud enough.
Be in mind that a lead guitarist whit a FenderTwin amp prefer to have the volume from his own amp at least 110dB ( mashall staks even more ), so normally the PA system will only supply vox, some keyboard and a little drum for clarity. Thatís loud enough to get concert felling to the fist 40-50 people in front of the band. The rest of the crowd will still get a god sound and be abele to talk while they drink their coffee. (I think some off them will like to drink beer, but you said it was a coffee house )
And then in the Weekend remove your subís and bring in the real PA.


Dalbjerg

If you cant join themóbeat them
:cannotbe:

Bose(o) 15th February 2004 11:55 PM

My school has fairly large speakers with an 18" two Mids (unsure of company) and four Motorola horns (piezo type). The sound is well, PA, and it works....okay, I guess. Okay, they sound brutal...I could build OB speakers with the same drivers, and it'll sound better but it's a school so whatever.

Anyway, we use four of these speakers and they seem to fill our auditorium fairly well, of course I'd prefer real speakers..though, I'm the only that does and that is why we have bargain-bins.

nicksmurf 16th February 2004 12:12 AM

All I'm doing is try to top the coffee house scene and provide FREE music. So the speakers I mentioned should do the job. But for a small place do you think I should go double that size? I actually know a club by me, all they run is 4 boxes hung from the sealing. They have 2 18" subs, 12" mids, and a horn in each. Running a couple killowatts, i can't remember what exactly. That's the Oden in Cleveland Ohio. Most the coffee houses have either little powered speakers or Peavy mixer amps and cheep stuff like that.

What would be the bear minimum to keep up a band (any style), for a place that should fit 100 people? aka oversized coffee house that has food... 4 ported 15", 4 12" mids, and I still have no qlue what high frequency drivers are good for PA systems. I know who makes cheep (motarola), middle (eminence) and more expencive (EV) drivers. To state the truth, this is were most clubs are lacking. Their high frequencies sound like distorted crap. Yes I do plan to fly my (high and mid) speakers, and I do know how to design and build speaker enclosures.

QUOTE]Be in mind that a lead guitarist whit a FenderTwin amp prefer to have the volume from his own amp at least 110dB ( mashall staks even more )[/QUOTE]
Yeah I played a gig last week. I think my 50 watt cheppo yamaha amp was louded than the sound system they set up for us (I had them mike it and they told me to turn it down after the sound check).

mikee12345 16th February 2004 01:46 AM

Quote:

To state the truth, this is were most clubs are lacking. Their high frequencies sound like distorted crap. Yes I do plan to fly my (high and mid) speakers, and I do know how to design and build speaker enclosures.

Cheap piezos are evil.
Overdriven tweeters will sound like crap
Clipping amps too dont help

You Need headroom.../

Cheers!

Centauri 16th February 2004 02:25 AM

Depending on music style, the EVM15Bs, while good speakers, may be a little lacking in power unless you get the proline (400W) versions. The 12Ls will sound nice. Appropriate horn drivers could be Eminence PSD2002, Peavey 22XT etc on CD flare. Definitely go for the 1" drivers. May be able to pick up JBL 1" drivers for good price S/H. The 12Ls will go quite high, so crossover to HF around 3kHz - this will prevent "nasties" if driven a bit hard. 4 flown top boxes and 4 sub boxes should make a great in-house PA.

Cheers

PS: Only horn-load the subs if you have enough room for large boxes, otherwise go BR. Horn subs would have advantage of greater efficiency. Alternatively, a tuned chamber band pass sub may work well.

sek 16th February 2004 02:31 AM

Quote:

Yes I do plan to fly my (high and mid) speakers,
Hmm, so all you actually need is a starting point on how to chose the right enclosures, what high frequency units to choose and how to (crossover) filter and amplify them?

Have a look at "UniBox" on this site: http://www.pvconsultants.com/audio/boxmodel/unibox.htm

It's a free Excel spreadsheet that helps you calculate box volume and tuning, depending on the desired response. Remember that those calculations depend on accurate data, I recommend you to measure your speakers individually...

Unfortunately I can't help you on this, as I don't have representative parameters of your EV chassis.

As you need hard- and software anyway for later measuring the results of your woodwork, have a look at SpeakerWorkshop: http://www.audua.com

It's a very nice, free program to make any electrical measurements you need in the first place. You can then use it (with a measurement microphone) to evaluate your woodwork. Depending on your results here you can start to develop a crossover.

Quote:

and I do know how to design and build speaker enclosures.
Yep. I'd recommend you to make simple enclosures, vented lows and mids, with regular shape. In your case I think it's better to have a good sound than good looking mid/high systems hanging. I say this because you probably want to upgrade soon (and can waste the cheap enclosures) :cool:

As you plan to do something for the sound quality of your house, you should have a look at Cara: http://www.cara.de/ENU/index.html

That's an online room simulation tool (follow "Service" on the left, then "Cara quick") that helps you to determine the best way to place your speakers (and listeners) in the room. If you're good :D you can even google up the free demo version of Cara (to download).

And confirm (using your measurement hard- and software) your simulations again.

As for amplification, you'll get an impression of your needs while you measure your speakers and boxes.

As for the Tweeters and horns, I'd recommend you to look for (good) used stuff, e.g. JBL, EV etc. on ebay. You could opt for Eminence or similar, but good used drivers and horns don't cost more. Try 1.4" drivers, 1" seems too small to combine with your midrange. Don't use a 2" even if it looks easier to combine with your midrange. A 2" compression driver would set you back to screaming, distorted highs.

Again, what's suitable (type and number of units) doesn't only depend on someone's subjective experience, but on what fit's your mid-cabs the way you build and use them (you get it, based on your measurements ;)).

100 people doesn't sound too much, but the room acoustics are the pitfalls here. Do a quick simulation for a starter and you can see how much work's awaiting you.

I'm sorry if that sounds too complicated. But that's the way you can get over the crappy sound that you hear in places where they have no idea. Even in a starbucks my ears get offended after I've paid five bucks for a stylish interior, so I know what you mean ;)

Just get a quick test with everything in the links (the Unibox site contains a huge amount of good speaker building software, e.g. for crossover design). The forum (and me) is here to discuss your findings.

Sorry again, it's as much amount of work as every engineer would have in your house, in case you would pay one to make a good installation :cool: while you can actually do it with very little money.

Quote:

What would be the bear minimum to keep up a band (any style), for a place that should fit 100 people?
Exactly what you're going to build, starting with the material you've got. One just has to do it good enough. :D

Hope this helps you,
Sebastian.

nicksmurf 16th February 2004 02:54 AM

It is a lot better to acheive good sound rather than good looks. I plan just to paint them black or something that matches the place and hang them either from the ceiling or wall. Cheeper and less clumzy than buying speaker stands or having them stick out of my subs on polls.

Thanks Centauri, you pretty much awnsered what I wanted to hear. And thanks SeK for that link, I downloaded it and will check it out. Looks cooler than the old dos programs I was using before! I have been actually buying all my EV speakers off of Ebay. They all work but are slightly screwed up. I might look for recone parts and recone them all myself. I've had one person warn me not to try because of the voice coil gap being so small in EVs.

Thanks,
Nick

P.S. Wonder if EVM-15b drivers are suitible for horn loaded subs? If they are, and they probably are, I guess I get to learn something new...


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