The above Ad will no longer appear after you Sign Up for Free!

amp matching for a small sound system

Discussion in 'Sound, Music, and Intercom' started by tweetersaway, Jul 11, 2008.

  1. tweetersaway

    tweetersaway Member

    Messages:
    80
    Likes Received:
    0
    Occupation:
    Lighting & Sound Supervisor
    Location:
    Mesa, AZ
    I'm currently working on getting together a small portable sound system that's mostly for a small cafeteria space and other gigs. The amp I'm looking at gives 160w/ch @ 8 ohms, and the speakers we're looking at are rated for 150w/300w rms/peak. I've never done any amp matching before, So I have no idea. Is the fact that the amp is rated higher than the speakers' rms bad and should be avoided, or is it ok or normal? thanks.
     
  2. waynehoskins

    waynehoskins Active Member

    Messages:
    782
    Likes Received:
    49
    Location:
    Arlington, TX
    160 compared with 150 is not bad. Power ratings are meaningless anyway.* :)

    What speakers and amp are you looking at, by the way?


    * - well, not meaningless, but there's a big difference between 160 watts at 8 absolute guaranteed minimum under full load 100 percent duty, and 160 watts at 2 with the ambient temperature inside the amplifier below freezing, absolute peak, right before the power transistor banks blow up.
     
  3. avare

    avare Active Member

    Messages:
    148
    Likes Received:
    8
    Location:
    Hamilton, ON Canada
    What are the gigs? What is important is the efficiency of the speakers. If you do not get enough volume, the matching is meaningless. If this system will be run by amateurs, then yes, the amp/speaker system is well matched.

    To paraphrase slightly, a well matched wrong system is still a wrong system.

    Andre
     
  4. TimmyP1955

    TimmyP1955 Active Member

    Messages:
    793
    Likes Received:
    55
    Location:
    Indianapolis
    The common wisdom (with which I agree) is that in order to get all the speakers will deliver, the continuous rating of the amp should be 1.5 to 2 times the continuous rating of the speaker. So if your speakers are 150 continuous/300 program, the optimal amp would be 225 continuous to 300 continuous. However, no matter how small the amp may be, if it gives you plenty of volume without clipping, it is big enough for the job at hand.
     
  5. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    on the lower end portable systems I would suggest that you look at a powered speaker, most have bi amp setups, which work well, give better performance and make setting up and moving the systems a breeze.

    Just a suggestion
    Sharyn
     
  6. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    A couple of things stand out. Are the speakers 8 Ohm? If not then the 8Ohm amplifier rating is not relevant. Also, a speaker would usually be rated 150W continuous/300W Program or 150W Program/300W Peak, for the Peak rating to be only twice (3dB) the continuous/RMS rating would be very unusual. I agree that it might help greatly to know the actual products involved.

    It is quite normal. However, I am very glad to see the comments already posted saying that what is "enough" power is based on the application and not just the ratings. Along with the desired levels, other factors in determining the proper power can include the type of content and the skill of the operators. If the source is heavily compressed music you may have to be more concerned with long term thermal problems than with peak levels. Conversely, very dynamic music may require that the system be run at a lower average level but have more headroom for peaks. Adding to that, a skilled operator can probably run a system much closer to the edge without damaging it than might a less experienced operator. But typically a 160W rated amplifier running a 150W continuous/RMS rated speaker would not be a problem.
     
  7. avare

    avare Active Member

    Messages:
    148
    Likes Received:
    8
    Location:
    Hamilton, ON Canada
    Operator Skill and Speaker/Amp Matching

    Thanks Brad for your post right above this one. I was going to expand on why I wrote

    after reading

    What TimmyP1955 is based upon knowledgeable operators. An amateur, especially one that thinks a sound system is operating at its best when it is distorting, will blow the speakers very quickly. You gave an excellent summary with (the bolding is mine, not museav's).

    To paraphrase slightly what has already been written, if the system will be operated by non skilled operators, then the amp is a good match.

    Skillfully,
    Andre
     
  8. tweetersaway

    tweetersaway Member

    Messages:
    80
    Likes Received:
    0
    Occupation:
    Lighting & Sound Supervisor
    Location:
    Mesa, AZ
    Re: Operator Skill and Speaker/Amp Matching

    Thanks everybody for the input. The more I read here and all over in the forums, the more I've been starting to look at active speakers as an alternative. The original system I was looking at was a 500 watt Behringer amp which pushed 160w per channel at 8 ohms with a pair of 2x10s made by (don't go off about this) Kustom. Frankly I am a little ashamed that I was seriously looking at Kustom speakers, but I've heard that they've done an alright job on these ones for low budget venues.

    Anyway, as I said, I'm now looking at active solutions because it just seems logical. I took a look at the Behringer Eurolive B212A, and it looks like a very good solution. I've read numerous reviews and talked to a few people who have all said very good things about the sound quality and durability of them, and I don't think I could ask for a better price as they weigh in at about 460 us for a pair. Any thoughts on these?

    For the most part, I will be the operator of this equipment. But those times when I'm not there, you never know who could be running the gear.

    Could someone please expain what exactly 'biamp'ed means? Does it just mean that there are two seperate amps for the tweeter and the woofer so there isn't a post-amp crossover? thanks.
     
  9. waynehoskins

    waynehoskins Active Member

    Messages:
    782
    Likes Received:
    49
    Location:
    Arlington, TX
    You've got biamping right.

    Behringer power and Kustom loudspeakers wouldn't be my first choice, nor would Behringer powered boxes. Actually, they'd be my last choice. But you're right, you can't do it for less money than that, 500 a pair. You'd spend that in conventional amplification, and you'd spend at least that per loudspeaker. Plus all the other goodies, and console and, and, and...

    What's the application? Lecture? Rock? Musical theatre?
     
  10. tweetersaway

    tweetersaway Member

    Messages:
    80
    Likes Received:
    0
    Occupation:
    Lighting & Sound Supervisor
    Location:
    Mesa, AZ
    I know a lot of people in the professional world don't like Behringer, but I've never had a problem with their equipment, and the price simply can't be matched.

    They will be used as mains mostly for relatively small live music venues, whether it be rock or whatever. Probably will be used as stage monitors for similar shows as well. Of course, you never know what you'll end up using it for. Possibly DJ-esque gigs and reinforcement for plays in small venues.
     
  11. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    just a few things to consider:
    Make sure that you try to compare them by listening to these vs say the JBL or Mackies

    Make sure you have a dealer that will support you, in case you have infant mortatilty problems


    Most of us wind up buying and selling gear all the time upgrading etc. In this mode, remember the true cost of an item is the purchase price LESS THE RESELLING PRICE. In general I have found that the most economic and reliable long range approach is to buy quality last generation. The first owner has taken the depreciation hit, worked out all the bugs and if you buy carefully you will find that the gear costs you almost nothing since you can resell it for almost what you paid for it.

    Just a thought to keep in mind
    Sharyn
     
  12. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    Price and quality do often relate, which is one reason many professionals avoid Behringer and some other low cost brands, however many professional's perspective on Behringer is as much, if not more, an ethical and moral issue than a technical one. That and if you have to deal with bands whose riders may specifically state "No Behringer".

    For DJ and contemporary music applications, many people find that a two-way speaker with a 12" woofer does not provide enough bass. Budget is certainly a consideration but I agree with Sharyn and suggest that you try to listen to some as well as some competitors before buying just to make sure they will work for you.
     
  13. waynehoskins

    waynehoskins Active Member

    Messages:
    782
    Likes Received:
    49
    Location:
    Arlington, TX
    For small stuff, give Mackie's SRM450 a listen. They're about as compact and portable and inexpensive as you can get, just about. They'll also handle some abuse.

    I'm not completely a Never Behringer guy, though I'd like to be from an ethical standpoint. I'm an Avoid Them Whenever Possible Especially For Anything Critical guy.

    All the Behringer I have are a couple of Multicoms as noncritical comps, and a couple of line mixers in Videoland.

    I buy older stuff, stuff that's more on the lines of 10 to 20 years old and has a reputation for being (1) good and (2) rugged. My amps at the church are Crown Micros, and I have less in them than I would have put into new Micros or new Macros or new PLXes, and I have amps that just work, and that I can fix if I have to.

    12s will do for most music if you've got subs under them. If you need one box that does it all, you need to go 15s. Give the SRM450 and the Eon a serious look.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice