# Using Pa speakers for my mains???



## aaron6939 (Jan 30, 2010)

I know a version of this question has been asked before in the forum but I thought I would renew. Here goes: I have a Yamaha HTR-5280 5.1 receiver and would like to use a pair of 150 watt Crate s10 pa's as my mains. The Crates sound amazing when powered from a standalone amplifier but when they are powered by the Yamaha, no highs are reproduced. In fact, I can put my ear right up to the tweeter horn and I hear nothing. I borrowed my dads old stereo speakers that he bought out of the back of a truck 30 years ago to see if it was the receiver, but they sounded fine. As a last resort I cranked the treble up all the way on the Yamaha and still get nothing. Any ideas?


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## jackfish (Dec 27, 2006)

How are you connecting the speaker wires to the Crate S10s? There are two 1/4" jacks, one input and one output. I believe the input jack should be used for a mono 1/4" phono plug wired for positive and negative. The output jack would not be used as it is used to daisy chain speakers together.


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## tcarcio (Jun 27, 2007)

I use a pair of B52 MX1515's for my mains and I was very happy with the result but I didn't have the problem you described. I have since replaced them with some classic B+W's that I found and I am selling the B52's. Maybe you have a cable problem? If your cable is wired wrong it could cause problems.


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## aaron6939 (Jan 30, 2010)

I soldered a male 1/4 mono jack onto the end of each 12 gauge speaker wire coming out of the receiver and plug that directly into the input jack on the crate pa.


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## aaron6939 (Jan 30, 2010)

Just as a last resort i did try switching the wires going into the receiver around just to see if I had soldered the 1/4 jacks wrong, thinking phase was the culprit. No change however.


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## tonyvdb (Sep 5, 2007)

I do have a question, do the speakers have a separate input for the highs? I wonder if these particular speakers are designed to be bi-amped?


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## tcarcio (Jun 27, 2007)

Those speakers only have one input and one output so something else is going on.


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## aaron6939 (Jan 30, 2010)

The crate pa's have two jacks on the rear panel: one input and one output for daisy chaining. As I said, hooked up to a powered mixer, which is the other amp I had mentioned earlier, the speakers sound great. Could it be something to do with the crossover assembly built into each speaker? Just a wild guess, I'm reaching because I do not understand what is going on at all.


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## tonyvdb (Sep 5, 2007)

And you have confirmed recently that they do indeed work properly with an external amp?


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## aaron6939 (Jan 30, 2010)

Yes, I have a stereo/mono amplifier that I use as my sub amp. I have used this to power the speakers and they sound as they should. It makes no sense, at this point I am more annoyed than anything.


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## tonyvdb (Sep 5, 2007)

Re you certain that your Yamaha is not in bi-amp mode? as it would only sen the lows to your mains.


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## aaron6939 (Jan 30, 2010)

Thats a possibility I guess, or at the very least, a new idea. I am unfamiliar with this term, how could I check if my amp is in "bi-amp" mode


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## Mika75 (Feb 5, 2009)

aaron6939 said:


> Thats a possibility I guess, or at the very least, a new idea. I am unfamiliar with this term, how could I check if my amp is in "bi-amp" mode


Connect a different speaker to the Yamaha ..what do u hear now ?


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## selden (Nov 15, 2009)

If there's no output at all from the tweeter, but the woofer is OK, then either the tweeter is blown or an internal wire has come loose. Given the physical abuse that public address speakers get, I'd guess the latter. Speakers aren't very complicated, so you might try opening it up and taking a look.

If that's what it is, and you or a friend are good at soldering, you might be able to fix it easily. If not, then a local A/V store may be able to recommend someone in town who can fix it.


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## tonyvdb (Sep 5, 2007)

aaron6939 said:


> Thats a possibility I guess, or at the very least, a new idea. I am unfamiliar with this term, how could I check if my amp is in "bi-amp" mode


As Mika77 said connect a different speaker to the Yamaha and if you have highs with it then my above suggestion is not the issue.
That said bi-amp mode means that your receiver can use the amps for the two rear channels (6 and 7) to power the highs and the main channels to power the lows. Bi-ampable speakers have two sets of binding posts on the back of them.


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## aaron6939 (Jan 30, 2010)

well thank you for all the ideas, I hooked up my rear surround speakers to the main outputs and they reproduce the highs and lows as they should. The crate pa's work perfectly when connected to a standalone amplifier. I have tried using a 5.1 sony receiver from a HTIB to see if there was any difference. If I crank the treble all the way up I do here some highs - nothing even close to what I know they can do. So the tweeters are working, something is just limiting their volume when connected to a surround sound receiver. The Pa's are rated at 150 watts rms, and both the receivers in this case are 105 watts a channel. would this have anything to do with it? In my mind it seems if they were underpowered, the tweeters would be the first thing to work. Maybe my Pa's are prejudice against surround sound receivers? Ha!


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## selden (Nov 15, 2009)

What's the nominal impedance of the speakers? I'm wondering if the tweeters have a very low impedance, too low for standard receiver amps to handle, although that's very unusual. 

If your receiver has preamp outputs, you might want to consider connecting those to the amps which work with the speakers and forgoing the receiver's own amps.


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## jackfish (Dec 27, 2006)

Those Crate S-10s have an impedance of 4 Ohms.


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## aaron6939 (Jan 30, 2010)

selden said:


> What's the nominal impedance of the speakers? I'm wondering if the tweeters have a very low impedance, too low for standard receiver amps to handle, although that's very unusual.
> 
> If your receiver has preamp outputs, you might want to consider connecting those to the amps which work with the speakers and forgoing the receiver's own amps.


They are indeed 4 ohms, but bypassing the receiver and using a separate amp would require the purchase on another amplifier...$$$...which seems silly since part of the receiver's job is to power speakers. I mean if they are not going to work, they are not going to work; though I would like to understand why.


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## tonyvdb (Sep 5, 2007)

Does the Yamaha HTR-5280 have YAPO? If it does I would hook up the speakers again and run the YAPO setup.


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## aaron6939 (Jan 30, 2010)

tonyvdb said:


> Does the Yamaha HTR-5280 have YAPO? If it does I would hook up the speakers again and run the YAPO setup.




I don't believe this receiver has the YPAO function.


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## selden (Nov 15, 2009)

Many receivers simply can't drive 4 ohm speakers: they require more current than the receiver can deliver. I fear this might be the underlying problem. Many speakers which are nominally 4 ohms actually have significantly lower impedances in some frequency ranges.

A quick Web search suggests that your AVR has a 4/8 ohm switch. Its purpose is to reduce the receiver's output voltage so that a 4 ohm load won't draw too much current. Does using that make any difference?


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## aaron6939 (Jan 30, 2010)

So the lower the ohm load, the harder the receiver must work? Or is it the other way around?


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## aaron6939 (Jan 30, 2010)

Ohm=resistance correct? so then the lower the ohm load the easier it is to push electricity through the speaker?


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## tonyvdb (Sep 5, 2007)

selden said:


> Many receivers simply can't drive 4 ohm speakers: they require more current than the receiver can deliver.


That dose not explain why he can hear the lows but no highs. If what you were saying was true he would not get any sound out the the speaker.


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## selden (Nov 15, 2009)

Right:

Simplistically, it's what's known as Ohm's Law: E=IR or, rearranging, I = E/R
The current (i) goes up as the resistance (R) goes down for a given voltage (E) [ E stands for Electromotive Force which is measured in Volts]

To make a louder sound, the receiver generates a higher voltage until it either exceeds the power rating of the power supply (Watts = I E = Voltage x Current) or it reaches the "voltage rail" -- the maximum voltage that the power supply can generate. 

I called this "simplistic" because speakers aren't resistive loads: they have both inductive and capacitive impedance effects which vary with frequency. It gets pretty messy.


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## selden (Nov 15, 2009)

tonyvdb said:


> That dose not explain why he can hear the lows but no highs. If what you were saying was true he would not get any sound out the the speaker.


It's not "all or nothing": most of the current flows through the load (speaker driver) which has the lowest impedance -- usually the woofer -- so low frequency sounds are being generated. The tweeter has a higher impedance, so relatively little current flows through it. Why it's inaudible, I really don't know.


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## aaron6939 (Jan 30, 2010)

I have come to the conclusion that this is a very odd/rare problem since nobody really has a simple solution.


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