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06-20-2011, 12:42 PM
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#1
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Human being with feelings
Join Date: Aug 2010
Location: Seattle, WA
Posts: 211
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Matching a dual-mono speaker set up with an amp
Hello Everyone,
So, I've been tasked with putting together a dual-mono speaker setup in a small room (roughly 12ft. x 8ft.). I'm looking at using these speakers with this amp.
As I understand it, the general rule is that you want to "over-power" your speakers at a ratio of about 3:1 to 5:1. I realize this is a little overkill for the 60W (8 ohm) rated speakers, but does this look like it'll work?
Thanks in advance!
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06-20-2011, 01:09 PM
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#2
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Human being with feelings
Join Date: Feb 2011
Location: Salt Lake City, UT
Posts: 1,095
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What is this for?
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06-20-2011, 01:52 PM
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#3
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Human being with feelings
Join Date: Aug 2010
Location: Seattle, WA
Posts: 211
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I'm installing ceiling speakers for the Mother's Room in my church. So, it's a feed off the main mix to play at moderate levels (probably 65 to 70 dB).
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How can you tell the stage is level? . . . The drummer drools out of both sides of his mouth.
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06-21-2011, 05:19 AM
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#4
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Human being with feelings
Join Date: Oct 2008
Location: London UK
Posts: 125
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I would possibly go for another amplifier brand.
It seems somewhat over powered for an 8 inch public address/muzak system to my mind.
It should work though.
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06-21-2011, 06:58 AM
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#5
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Banned
Join Date: Aug 2007
Location: Too close to Charlotte, NC
Posts: 3,554
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I don't think overpowering for headroom is very important for ceiling speakers, esp. considering you won't have any low end. That amp is serious overkill, you need what, 10 watts to get as loud as you want to.
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06-21-2011, 08:51 AM
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#6
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Human being with feelings
Join Date: Aug 2010
Location: Seattle, WA
Posts: 211
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Thanks for all the responses!
So, basically, I only need to "overpower" speakers when I want to have crystal clear frequency response across the full spectrum (20Hz - 20kHz)? For instance, passive studio monitors or loud speakers?
Thanks again!
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How can you tell the stage is level? . . . The drummer drools out of both sides of his mouth.
Audiosyncrasy.com - Custom drum tracks for your project.
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06-21-2011, 09:44 AM
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#7
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Human being with feelings
Join Date: Aug 2010
Location: Seattle, WA
Posts: 211
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Okay, so I found an old amp of ours laying around . . . here's the manual for the unit.
If I run two speakers in the Mother's Room, at 8 ohms apiece, I can drive them in parallel, off one channel on the amp, which will yield 75 watts (according to the manual) given the following:
Zp = (Za x Zb)/(Za + Zb)
Where Zp = total impedance when running speakers in parallel.
Za = impedance of speaker 'a'
Zb = impedance of speaker 'b'
Plugging in the numbers . . .
Zp = (8 x 8)/(8 + 8)
Zp = 64/16
Zp = 4 ohms
Does this seem kosher?
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How can you tell the stage is level? . . . The drummer drools out of both sides of his mouth.
Audiosyncrasy.com - Custom drum tracks for your project.
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06-21-2011, 09:54 AM
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#8
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Banned
Join Date: Aug 2007
Location: Too close to Charlotte, NC
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That will be perfect. Feed one channel of the amp a mono (L+R) signal, and you'll have the other channel available to feed something else. Typically you might feed the other channel a microphone.
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06-21-2011, 09:59 AM
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#9
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Human being with feelings
Join Date: May 2009
Posts: 29,260
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Quote:
Originally Posted by Audiosyncrasy
Thanks for all the responses!
So, basically, I only need to "overpower" speakers when I want to have crystal clear frequency response across the full spectrum (20Hz - 20kHz)? For instance, passive studio monitors or loud speakers?
Thanks again!
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Yes and no. Part of the "overpowering" is so the amp doesn't distort trying to drive the speakers since distortion via clipping is worse for a speaker than being slightly overpowered. There are two major types of speaker failure, massive overpowering and eventual coil failure due sustained heat from distorted signals...
So you really only need enough headroom to allow driving the speakers without distortion from the amp. That being said that amp is probably still a little overkill or just use one channel. Based on the speakers being wired in stereo you'll get about 350 watts RMS and 700watts peak from that amp which could result in the other type of damage to the speakers "massive overpowering". I think something close to 1/2 that power would be closer (provided those specs reflect the actual performance of the amp).
Karbo
Karbo
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06-21-2011, 10:16 AM
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#10
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Human being with feelings
Join Date: Aug 2010
Location: Seattle, WA
Posts: 211
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Quote:
Originally Posted by karbomusic
Yes and no. Part of the "overpowering" is so the amp doesn't distort trying to drive the speakers since distortion via clipping is worse for a speaker than being slightly overpowered. There are two major types of speaker failure, massive overpowering and eventual coil failure due sustained heat from distorted signals...
So you really only need enough headroom to allow driving the speakers without distortion from the amp. That being said that amp is probably still a little overkill or just use one channel. Based on the speakers being wired in stereo you'll get about 350 watts RMS and 700watts peak from that amp which could result in the other type of damage to the speakers "massive overpowering". I think something close to 1/2 that power would be closer (provided those specs reflect the actual performance of the amp).
Karbo
Karbo
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Awesome! That makes sense.
Quote:
Originally Posted by JHughes
That will be perfect. Feed one channel of the amp a mono (L+R) signal, and you'll have the other channel available to feed something else. Typically you might feed the other channel a microphone.
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Cool. Thanks for taking the time to look over this stuff. I took circuits classes in college for the fun of it (yes, I enjoy torturing myself with electronic circuits theory at 7:30 am in the morning ), but I'm having to dust out all the cobwebs.
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How can you tell the stage is level? . . . The drummer drools out of both sides of his mouth.
Audiosyncrasy.com - Custom drum tracks for your project.
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06-21-2011, 11:59 AM
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#11
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Human being with feelings
Join Date: Mar 2009
Location: Maryland
Posts: 75
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Think ahead...
Most likely, sooner rather than later, someone will ask you to run more speakers to other rooms. That being said, you need to seriously consider going with a 70-volt system. Please see the link for more explanation.
http://www.alectrosystems.com/audio/...ion/70volt.htm
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06-21-2011, 04:58 PM
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#12
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Human being with feelings
Join Date: Feb 2011
Location: Salt Lake City, UT
Posts: 1,095
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I was about to recommend a 70 volt system myself. Definitely, especially for a church. In the future they'll be able to add rooms and even mics to address people through them as well.
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