----------------- Original Message -----------------
From: Evan
Date: May 31, 2006 2:06 PM

> hey i have a band and i'm look for a good pa system
> do u know of any good ones to buy?


------------------- Reply Message -------------------

Oh, you may not want to get me started, I don't know if your question is a trap for me or if it will be one for you, but the answer is very multi-layered.

It should be design for the specific situation with enough allowances to tolerate for extreme physical stresses which live music may present to each component. There are so many parts in an effective system, that knowing what amount of power (how it's measured) can and can't be allowed to go where is very hard to judge and later make fool-proof.

In addition to not blowing up while operating, the systems must have enough acoustical output for your band. Your monitor system should be capable of being 6dB louder than your band when they are playing their loudest. The main system should be capable of being at least 6dB louder than the monitor system. Do the math and you find you need lots of very loud speakers and amps, or else you could consider everyone learning to turn down together, no?

As power is resolved, the tone problem should be resolved at the same time. In order for a speaker to be equalizable it must first have a natural tone. To acheive this all frequencies must propagate from the speaker so that all frequencies arrive at the listener's position at the same time. Otherwise the time slur will cause a frozen-flanger-like sound to alter the tone no matter how hard you try to eq it.

The manufacturers that are recognized world wide for making temporally accurate loudspeakers are Meyer Sound Labs, L'Acoustics, Nexo, EAW and Martin. Some make traditional speaker products for music store retail sales as well. Meyer Sound, considered the best in the world, and top in world-wide sales for concert tours and Broadway makes only top of the line, very accurate and temporally flat speakers.

Since about 97f all distortion heard by the audience is due to anomallies in the speaker/room interreaction, it is designing a system which reacts properly with the room which becomes most important. Also important is durablity, which over time can predictably make a better engineered speaker/amp interreaction save money if the device is used for a significant amount of time.

This was all documented and proven true in the early 1900's. Despite recent restaurant and bar owner's attempts to make us think cheap, the most modern math and measurements continue to prove that cheaply designed speakers are tuned to not destroy themselves at the cost of being recognizably unnatural in sound.

Other important elements are proper wiring and grounding and signal routing, enough inputs for the signals that need to be reinforced, and the completeness and wholeness of the package conceptually. The system's grounds must be properly connected and the whole system must tap to ground at one un-point.

Maybe most important, is the operator must be competent and a very honest listener. And not buying something you don't need - soooo many people mess that one up.

When in doubt, sub-contract the job to a sound professional. Guys like me cut right through the long math and the hype and deliver a service no single band starting could ever afford.

-dave
http://davemix.tripod.com/services/


It may seem like a big PA for an acoustic band, but actually the math shows this is one of few occasions the power ratios are truely right.


Drummers can be very loud so any speaker the drummer listens to must be capable of being louder than him. A tall order.

Evan's First Response
----------------- Original Message -----------------
From: Evan
Date: Jun 1, 2006 3:00 PM

hey thanks right now i have a behringer power amp 2400 watts and i run that through a peavey mixer powered but dont use to power. and my mains i have 2 are peavey tls seris 5x and my monitors i have 2 are peavey tls seris 2x so i think its 600 watts per speaker if thats correct do u think thats enough power. because we play rock.

thanks again,

-Evan

----------------- Original Message -----------------
From: DaveMIX
Date: Jun 2, 2006 8:48 AM

Evan,

Well I can't tell from your quick description, but maybe you can tell by just listening.

Quick answer: You list Watts of your amps, but this does little to help anyone find the acoustical output. Watts are measured in many different ways. For example: 2400 watts could mean 1200 watts peak from two channels into the greatest load the amp can handle, which is about 175 watts RMS per channel into 8 ohms, or 2400 watts could mean 2400 watts RMS into each channel which would be 4800 watts RMS from both and about 19,000 watts peak when adding both channels together. We also need to know the speaker's RMS and Peak capabilities, load, and most importantly efficiency. Thirdly, we should know the cable's length, and cauge to calculate the losses the wire contributes to the power transmission.

Long answer: Give me the model numbers of everything important (you have listed the speakers already, I think), the guage and length of the speaker wire, and I'll look up numbers on the internet and do the math.

Don't forget: If you can't hear everything, it is much easier to turn the loudest stuff down, than buy more gear and try to be louder still.

-dave

Evan's Second Response
----------------- Original Message -----------------
From: DaveMIX
Date: Jun 3, 2006 7:08 PM

ok the mains are http://peavey.com/products/browse.cfm/action/detail/item/108381/number/00571060/cat/110/begin/1/TLS? 5X.cfm
The moniters are http://peavey.com/products/browse.cfm/action/detail/item/116196/number/00574020/cat/112/begin/1/TLM? 2X Floor Monitor.cfm
the power amp is http://www.behringer.com/EP2500/index.cfm?lang=ENG
the mixer is http://www.peavey.com/products/browse.cfm/action/detail/item/111151/number/00510600/cat/88/begin/1/XR® 600G.cfm

But on the mixer it is a powered mixer i dont use the power i just go from the monitor and main outputs on the mixer.

Thanks again,

-Evan




----------------- Original Message -----------------
From: DaveMIX
Date: Jun 11, 2006 4:55 PM

Evan,

Here are the results of my study:

PART 1 AMP

Your amplifier is rated 1200 peak watts max for each amplifier in the maximum load while amplifying a single note. In this way the manufacturer has secured the highest possible number for "Watts" when marketing their product.

Your RMS power would be less for several reasons. First the signal you will be usiing is music, not a single pure tone. Secondly, you probably have two mains and two monitors, so you will be running the amps at 4 ohms, not 2 ohms. And most importantly, the amp is rated for peak power, but you will be using the device dynamicly and peaks will distort if you operate the device with peaks greater than the peak rating.

AES and SMPTE (Audio Engineering Society and Society of Motion Picture and Television Engineers) both recommend a minimum of 6dB difference between Peak and RMS performance or else the listener will suffer fatigue from the unnatural sound. You can hear it too, when vocals sound harsh when important notes are hit, for example. So you're going to learn to use it in a way it won't distort - this means RMS usage will be 1/4 the power of the Peak rating to achieve acceptable listening conditions.

Your amps are rated:
1200 Watts Peak into 2 ohms with one pure note
750 Watts Peak into 4 ohms with one pure note
650 Watts Peak into 4 ohms with music (20 to 20K)

1/4 of that rating is 165 Watts RMS (with 650 Watts peak) from each amp.

Each amp delivers to two speakers which will be driven with 82 Watts RMS (with 325 watts Peak)

PART 2 SPEAKERS

Your mains, the TLS-5X is an 8 ohm speaker with 1/4 inch jacks, rated at 1000 Watts peak and 500 Watts RMS with vocal music (66 to 20k). Same as the math above the speaker's useful RMS output is 250 Watts each. At greater than 1000 Watts Peak, your speaker may become quickly damaged, or the tweeter protection will turn off the highs, or both. A bad place to be.

Your monitors, the TLSM-2X is very similiar but with a 12" woofer. An 8 ohm speaker with 1/4 inch jacks, rated at 1000 Watts peak and 500 Watts RMS with vocal music (68 to 17k). It has the same crossover with protection provided for the tweeters only. The efficiency is not listed but assume the smaller driver, and box make it -2dB the performance of the mains.

The frequency response is the speaker's output, but reflects the desired input as well. Since the speakers are not rated to create deep bass, it would be very unwise to put such sounds into the mix going to such speakers. Turning down the lowest Graphic EQ slider on the XR600G mixer would increase the life of the speaker with the downside being the artifacts of the equalization effecting perceptability somewhat.

Extreme highs can also be harmful. Since the speaker can't produce above 16k, there's no point trying to put a correction in the mix - most rooms fall off into 100
istortion above 14k anyway for many complex reasons beyond this report.

There is no protection for exessive use of the woofers. The tweeters are always ( 99rated for much less power than your woofer, so if you amp goes full power reproducing only a Flute for example, the tweeters will experience far more than their rating. This is the reason for the tweeter protection circuit, just realize it is not a foolproof protection, in fact the protection itself can fail sometimes.

PART 3 ACOUSTIC OUTPUT

Your mains are rated to produce 98 dB at 1 meter with 1 watt.

It's a logarithmic equation, you may be familiar with such math, but here's the easy way to remember it:
10x the watts = 10db

So for your speaker:
1 watt = 98dB
10 watts = 108dB
100 watts = 118dB
1000 watts = 128dB

So your speaker can withstand peaks of 1000 watts, your highest possible resulting acoustic output is 122dB RMS/128dB Peak at one meter from the ideal amplifier.

Your amp delivers 82 Watts RMS (with 325 watts Peak) to each speaker. Which is about 116dB RMS/123dB peak in your situation.

PART 4 ANALYSIS

116 dB RMS is a bit low for rock and roll, there are many other uses which demand less of a speaker than rock. Exercise classes and church sermons for example, so you are in the corner of the industry that really needs all the output speakers can produce. I would recomend a system which produces 130 dB RMS/ 136 dB Peak per speaker to amplify a rock band.

Looks like you should stick to amplifying vocals only and definitely keep bass notes and bass drums completely out of the mix.

Still, the Amplifier's specifications are especially misleading to the point I don't trust them at all. The 650 Watts into 8 ohms has few descriptions of what that measurement means. Lets imagine that it means 650 Watts RMS - your going to have a lot more volume and a lot of failures due to excessive power. 650 watts RMS includes 2600 watt peaks sometimes and that will take your speakers out especially if someone makes a high note all by itself. But I consider it highly unlikely that a company like Behringer would have specs that were generous, far from it. I can assume from how they rate distortion - they are trying to be misleading to new consumers, in my estimation.

If you control levels carefully you can obtain a great sound performance, but don't be assuming your set-up would make every band happy, because some don't like to compromise. Not having the band in the PA can make for some strange issues, like hearing the vocals well at a distance, but not the guitar or just the opposite. Be on the look out for this issue - get a wireless guitar set-up or a long cord and walk around and listen. That's reason 101 for having a soundcheck.

To increase your sound levels to my minimum recomendation would require a new speaker design (or about 14 more same speakers - got room for that?), and a perfect-fit amount of amplification. It would also need to be at least as reliable as you are now, you should have better protection especially with nothing protecting woofers.

PART 5 ADDITIONAL ISSUES

I made a point before that the mains need to be 6dB louder than the same signals in the monitors. Your two amps and two speaker types are rated for the same power. Even if you mixed the mains 6dB louder than the monitors, this relationship would fail once the main amplifier was in overload, and the monitor amp was not. Unfortunately this will be a critical part of the music which should deliver the vocals as clearly as possible so the audience can percieve everything without additional loudness being required.

To do this:
Use 1amp channel for each main
Use 1mixer amp channel for each monitor

This requires additional Anaysis
Your amp
450 watts peak into 8 ohms
115 watts RMS into 8 ohms

Speakers as you use them now:
116 dB RMS/123 dB Peak Mains
114 dB RMS/121 dB Peak Monitors

Your speakers with my new idea:
118 dB RMS/124 dB peak Mains
112 dB RMS/119 dB Peak Monitors


This way distortion doesn't also alter the relationship between mains and monitors. You almost get the right ratio, and you have the effect of adding two more main speakers without the downfall of the destructive interference and amp and transport costs.

If the mains turn off or protect themselves, go back to the other configuation immediately - this is all at a bit of risk because you have little protection at the drivers.

PART 6 YOUR FEE

Rate $30/hr
Hours 8 (minimum hours)

$240 Sub-Total
-$240 MySpace Friend Discount

$0.00 Total



Stay in touch, I'm curious how it turns out.
-DaveMIX
Starground Audio
Newark Delaware


Evans' Third Response

----------------- Original Message -----------------
From: Evan
Date: Jun 11, 2006 5:10 PM

so what ur saying is take the mains and put them into the power one per chanel and use the powered mixer for the monitors. also if i bought another power amp would that help? last what ur saying for the rock band is dont mike the drums or guitar and dont di a bass just use the pa for singing?





----------------- Original Message -----------------
From: DaveMIX
Date: Jun 12, 2006 2:36 AM

1 Yes, that was my final suggestion, based on what you had. Also, since the amp is almost capable of 1000 watts peak, but not into 8 ohms, you get a bit more power but should still be safe. The idea of actually trying to run the maximum every moment is going to end up with enough strain to reduce reliability, you're best to have a safety zone.

2 No, I don't recommend more power without more power-acceptable speakers, and only if the end result will actually be louder which sometimes it isn't. Without changing speakers you get 2dB closer to the max acceptable limits while still having about 3 dB more that the speaker can take compared to what the amp can do. Going any closer to the speaker max isn't not worth doing.

3 Yea, putting it all in the mix, you aren't able to do, barring extremely low stage volumes throughout your show. Plus it's a lot more gear and channels than you may have now. It can add up fast and cost a lot.

My fix, may help, and requires maybe a few wires, or maybe no gear at all. Putting the Behringer Amp in parallel mode is easy. The math was rushed at the end, you will have even less power in the monitors than I stated before, so check it out with an open mind, you may want more power in the monitors, especially when the band practices and you don't use the mains.

Also keep your eyes on overload indicators - Red on the Behringer, and Yellow on the far right of the Mixer, and avoid those conditions.

Tell me how it works.

-dave



Evan's Fourth Response

----------------- Original Message -----------------
From: ROCKSTAR EVAN
Date: Jun 16, 2006 3:43 PM

hi dave,

What do i need to mike drums guitar and bass? and shouls i get the tls serius a a subwofer?




----------------- Original Message -----------------
From: DaveMIX
Date: Jun 16, 2006 3:21 PM

The latest questions have already been answered. The best manufacturers of concert speakers are Meyer Sound Labs, L'Coustics, EAW, Nexo, Martin, and D&B, I forgot D&B they're quite good too. Notice Peavey, Fender, Community, Behringer, Cerwin Vega, EV, JBL are not mentioned because their products are not always good enough for concert use.

It is very hard to recomend a specific product set without knowing the artist's show and the budget involved, it would likely be bad advice. Right now you've done just about all the "impulse buying" you can do (even if you tried real hard to be careful, I call it impulse buying because few music stores can help you, they just sell stuff). Your big choice is to take a big plunge and have a system designed that is complete and meets all your needs at a cost tens of times more than you've ever spent on sound, or just stick with what you've got and reherse and do small shows with it. This way you save a ton of money, especially if your band breaks up. You band might grow faster than you can afford a great system, and hiring sound is a perfect solution for that because you hire companies with enough gear for each type of venue. So you play an arena, you don't have to deplete your funds to buy ten more power amps. Makes sense, yes?

Your current set up is far from ready to handle amplifying drums. You don't have enough equipment (crossover, amp, cables, sub-woofers, mikes, mike cables, mike stands, truck space). You also don't have enough acoustic power from the current equipment and no clear way to upgrade what you have.

I've made a few assumptions about cables, mikes, and your budget. If you're very rich, that dream rig could be assembed in a month. But that's no too likely.

-dave


Evan's Fourth Response



----------------- Original Message -----------------
From: DaveMIX
Date: Jun 12, 2006 1:53 PM

Dave,

Thanks that did help but what do u suggest for a rock band pa system speakers and monitor, subs, ect? also if i did get new equipment whats good stuff to buy? and last for what i have right now i shouldnt mike drums right?

Thanks again,

-EVAN



Evan,

The answer to your question has already been given to you.

Reread what I've already said.

In addition, your system must produce 110dB in the listening area, which will vary, right? Your speakers produce 118dB at one meter, which means after at 2.2 meters you're down to 110dB. 30 feet into the room, the two speakers are below 100dB. So you are way off on the amount of acoustic output needed in the mains system. Why add subs to that? You shouldn't, if that's the case, should you still be wondering.

You, like everyone else, needs the system shown below. But how many of us will do the kind of work to afford it?