|
|
Joined:
May 2006
Posts: 35
Location: Knoxville, TN | I am not much of an electronics guy but can any of you tell me if I have a PA mixer head that is pushing out 200watts and I have 4 speakers that will carry 60watts each, will my speakers suffer any damage? One person told me that you want more power on the head than in the speakers. He said problems occur when it's the other way around. Any info would be greatly appreciated. |
|
| |
|
Joined:
July 2002
Posts: 1900
| A few questions...What are the ohm ratings of the 4 speakers, What is the ohm rating of the amp? Are the speakers powered in series? Four speakers rated at 4 ohms each will present 16 ohms of resistance to the amp. If the applicable ohm ratings match, then it is better for the amp to have a higher watts rating than the speakers. There's alot of ohms/watts/clipping info on the net, just google it up.. |
|
| |
|
Joined:
September 2004
Posts: 777
Location: East Wenatchee, WA | This must be part of that redundancy thread?
Shandy. The answer is....depends.
I have been running and studying PA's for 30 years, but am not tech savy enough to give you all the technical answers but....
A leading cause of damage to speakers is called "clipping". It is most common when driving speakers by an underpowered amplifier. As the amp is reaching for the power it needs to drive a particular note(s) in the music, and it runs out of steam, it "clips" which as the name implies, cuts off the signal which affects how the speaker is being asked to perform to such a radical degree it can result in a torn voice coil or cone.
I would guess that clipping causes more speaker damage than just blowing up a speaker by over-powering it.
There are a lot of unknowns here. For instance, what is the real rating. 200 watts peak is nearly meaningless, whereas 200 watts RMS is a generally accepted measure of continuous power. Also, what is the impedence of your speakers and amp (at rated power).
For example, ( I am using memory here, so may not be totally accurate) my Mackie 1200 is rated at 1200 watts at 2 ohms in mono, and it goes down from there. The real number I use is about 350 watts per side at 4 ohms (stereo) well under the rated power number. I am running my Mackie into an elderly set of Electro Voice speakers that are rated at something like 120 watts (15" 3 ways). Now before you think, whimpy speakers, I bought these units due to their "efficiency" or in other words, ability to make loud noise on low power. My original amp was 75 watts a side, and I could just about give you a nose bleed in a small church setting. BUT...you will note that with this lower powered amp and higher powered speakers, I kept a keen sense on how hard I was driving the amp. If my "clip sensor" started winking, I backed it off (many amps now have that) and consequently my EV's have lasted me since 1982 or so and will still give you a headache.
So, with your set-up, first make sure of the impedence. When you hook up the speakers, are they 4 ohm or 8 ohm, are you hooking in series or parallel (series I believe reduces your 4 ohm speaker load to 2 ohms, many amps can't handle a two ohm load, whereas 8 ohm x 2 would be a 4 ohm load). You need to be aware of what your demands are on your amp/speakers. Large or small venue etc.
If running your amp much over "unity gain" (typically best signal/noise ratio) which if it isn't marked, assume around 2/3 to 3/4 throttle) you should consider a bigger amp. While your amp may have clip protection, few speakers do, and the real expensive damage is when you blow a voice coil out of a speaker, and clipping will do that for you.
Clear as mud...good...back to the swamp. |
|
| |
|
Joined:
March 2004
Posts: 629
Location: Houston, Texas | Originally posted by JeffreyD:
When you hook up the speakers, are they 4 ohm or 8 ohm, are you hooking in series or parallel (series I believe reduces your 4 ohm speaker load to 2 ohms, many amps can't handle a two ohm load, whereas 8 ohm x 2 would be a 4 ohm load). You need to be aware of what your demands are on your amp/speakers. I am no Sound Engineer, but when wiring in series, the impedance is additive. When wiring in parallel, the impedance is less than that of the highest impedance element. Four 4 ohm speakers wired in parallel would result in a 1 ohm load.
Be careful! |
|
| |
|
Joined:
December 2003
Posts: 1071
Location: Carle Place, NY | SG: You don't mention what kind of speakers you have. Are they in separate cabs or all in a row? What size are they?
Years ago there used to be column PA speakers with 4-6 speakers in each cab. Is that what you have? |
|
| |
|
Joined:
May 2006
Posts: 35
Location: Knoxville, TN | I have two 60watt Kustom speaker cabinets (8 ohms each) and two 60watt floor monitors w/volume control (also 8 ohms). I am wanting to use a Peavey XR-600G head which has 2x200 watts at 4 ohms DDT protected power, FLS® (Feedback
Locating System), Digital effects including Reverb, Delay, Vocal Exciter; Two 9-band graphic EQs (one assignable to monitor or channel 1), Input signal present peak indicators, 7 channels with 3-band EQ and monitor send, Mic mute switch and 6 XLR inputs with 48 volt phantom power.
thanks for the info guys; will it work? |
|
| |
|
Joined:
March 2004
Posts: 629
Location: Houston, Texas | Originally posted by Shandy Glover:
I have two 60watt Kustom speaker cabinets (8 ohms each) and two 60watt floor monitors w/volume control (also 8 ohms). I am wanting to use a Peavey XR-600G head which has 2x200 watts at 4 ohms DDT protected power, FLS® (Feedback
Locating System), Digital effects including Reverb, Delay, Vocal Exciter; Two 9-band graphic EQs (one assignable to monitor or channel 1), Input signal present peak indicators, 7 channels with 3-band EQ and monitor send, Mic mute switch and 6 XLR inputs with 48 volt phantom power.
thanks for the info guys; will it work? It sounds to me that if you wire one Kustom 60w, 8 ohm cabinet and one 60w, 8 ohm floor monitor in parallel to each output of the mixer/PA, you would be in business. Wired in parallel, the load would be 4 ohms on each channel with a power dissipation capability of 120w.
Since the output of each channel is rated at 200w at 4 ohms, don't push the volume output. Should sound sweet and clean, but keep the power output at a reasonable level.
All that being said, its better to get someone like Paul Templeman to ok this!! I'm not a sound engineer but I do know a little about electronics, or used to anyway. :( |
|
| |
|
Joined:
September 2004
Posts: 777
Location: East Wenatchee, WA | """I am no Sound Engineer, but when wiring in series, the impedance is additive. When wiring in parallel, the impedance is less than that of the highest impedance element. Four 4 ohm speakers wired in parallel would result in a 1 ohm load"""
See...told you I would mess that one up.
Personally, I think you are fine with this arrangement. I just bought the same head for our church, and I believe it allow you to drive the left channel amp as mains and the right as monitors(feeding through a monitor circuit and eq). Two outputs on the back of the amp for each set up or with 8 ohms speakers, you can chain the speakers to each other (2 on each side).
The Kustoms are similar in spec to our Sound Tech's and they are a relatively "efficient" speaker, so I have a feeling if you hook it all up, you will find that there will be a lot of volume at relatively moderate settings. To maximize what you have, make sure your instruments and mic's are being set at a high enough gain that you have the best signal going into your amp.
If you need more volume than this combination will but out (or to fill larger venue's), you better be thinking about a trade-up in both amps and speakers. Just not enough horsepower there for more than a smaller club size situation. |
|
| |
|
Joined:
February 2002
Posts: 5750
Location: Scotland | As the Peavey has 2 power amps which can take a 4 ohm load each, it is capable of running four 8 ohm cabinets, but your speakers are under-powered if you start pushing the amp to anything but polite levels. Run the Kustoms from one amp and the monitors from the other. The XR series amps can produce a respectable sound, but you should think about investing in some better, higher powered speakers. Personaly I'd dump the mixer amp and go for a pair of good active speakers. Watt for Watt actives tend to be more efficient and sound louder and cleaner than a passive system of the same wattage. |
|
| |
|
Joined:
May 2006
Posts: 35
Location: Knoxville, TN | I do a two man acoustic show; just two mics and two acoustic/electric guitars is all we are running. What would you recommend if we upgraded our entire system? Currently we have a Kustom 60w mixer/head and the aforementioned 60w speaker system. |
|
| |
|
Joined:
February 2002
Posts: 5750
Location: Scotland | In terms of sound quality, portabilty/loudness ratio and price point there's very little on the market that can compete with a pair of Mackie SRM450's. Only other thing you'd need is a little 4 channel mixer with FX and EQ. Alesis, Yamaha, Mackie and Behringer make affordable compact mixers that will do the job. You could add a Mackie SRM350 or 2 to use as monitors. Depending on the size of the clubs you play you could probably get away with SRM350's for the main PA instead of the 450's. The Bose L1 system is worth investigating also. |
|
| |
|
Joined:
September 2004
Posts: 777
Location: East Wenatchee, WA | For a 2+2 small venue act, I would probably go with the new BOSE L1 PAS system. 4 channels (you can buy a cheap sub-mixer if you need more) light weight, easy set-up and most reviews say in a small to medium sized club venue it rocks. Plus no need for monitors, little or no feed back problem and while typical BOSE expensive, it is not much more than you would pay for a set of Mackies and related mixer.
When I decide I don't want to pack around the Mackie/EV gear anymore (any day now that my body hurts from any lifting), I will probably keep my Tascam 2488 and buy the Bose system. Nothing else required for 8-12 channels depending on how I hook it up.
P.S. I did hear the BOSE system used in a church once with about a 200 plus member congregation. They used two of them with their 8 member worship team (4 vocals, two guitars, bass, drums). Sounded fantastic and the worship leader said they were just idling power wise, so they must have the guts to do a good size room. |
|
| |
|
Joined:
February 2002
Posts: 5750
Location: Scotland | I had a Mackie rig with 3 SRM450's and an SWA sub. Sold the lot as soon I got the Bose system. |
|
| |
|
Joined:
May 2006
Posts: 35
Location: Knoxville, TN | Problem solved!!
I bought a Peavey MP5 150w mixer yesterday. Hooked the main speakers up to it, then ran a line level out to my Kustom 60w head for my monitors and everything is sounding SAWEEEET!!!! Best sound I have ever had. I don't need much; it's just me and another fellow (2 vocals, 2 guitars)
Thanks for all the info guys! |
|
| |
PA system setup question
