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I'm over-driving my keyboard pa/amp. What should I change?


Tullsterx

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My stage amp consists of a Technical Pro SLIMPRO3000, 300W per channel @ 8 Ohms, and two passive Wharfedale Titan 8s. And I'm regularly overdriving it into the red. . . what do I really need to change? I guess I need more power? Or would a change in speakers make a difference? Or should I elevate the speakers instead of angling them up from the floor? 

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The speakers are on the floor behind me to each side angled up. I've tried them forward, underneath my keys on either side, also. I can't much difference between the two positionings. One things is, we're really pretty loud. So, maybe we/I just need to turn down.

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Sound pressure level (SPL) is a combination of power output from the power amp, the speakers being driven by the power amp and the enclosure the speakers are contained in. 300 watts (assuming the measurement is RMS) should be sufficient to provide enough power. Sounds to me that the issue may be in the inefficiency of the speakers you are driving the power through or the enclosure the speakers are attached to.  Is the enclosure a mismatch for the speakers, i.e. perhaps the enclosure's cubic footage is inadequate to produce the output level when being driven by 300 watts.  Try dropping the speakers into larger enclosure and see if that changes the overall output level.  If not, look for speakers that are more efficient (as well as match up against the speaker compartment's cubic foot volume) and you will find that the output will be louder.  Pyle speakers typically work well with a small cabinet enclosure as they don't require alot of cubic footage from an enclosure perspective.

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Are you overdriving the amp, or are you clipping the inputs?

 

i.e. exactly which lights are blinking?

 

I have never used your amp, nor read the manual, but if the "protect" light is not blinking then I think you should turn the CH A or CH B level up and the volume knob on your keyboard down.

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Line level confusion between keyboard and amp input. I had the same problem.

 

Several solutions:

1) never turn up your keyboard

2) put a 30 dB attenuator between keyboard and amp... Good luck finding one. Specs exist on-line to make one. http://www.epanorama.net/circuits/line_to_mic.html I was thinking of making patch cords with attenuators built into the plug.

3) use a DI box and XLR amp inputs (best for you)

4) this worked for me, but won't work for you...

 

I had a similar problem in using an amp not specifically designed to work with hot keyboard line levels. Any level above about 2 on the keyboard over-drove the input stage of the amp. In my case, there were 1/4', XLR, and RCA inputs to each channel. The RCA jack accepted the hot headphone signal from an iPad, so I made patch cords with RCA plugs one one end. Worked perfectly.

 

 

 

 

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I guess i was making an assumption that you were using some sort of a pre-amp (like a mixer) between your keyboard and the amp. I hope you are not trying to drive the amp inputs directly from the keyboard outputs. You should be sending the output of the keyboard to a mixer first, then the output of the mixer to the input of the amp. You should see a fairly drastic positive result using a mixer in between the keyboard and the amp. Something lke this: http://www.musiciansfriend.com/pro-audio/alesis-s-6-6-channel-compact-mixer?pfm=rv

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delaware dave wrote:

Sound pressure level (SPL) is a combination of power output from the power amp, the speakers being driven by the power amp and the enclosure the speakers are contained in. 300 watts (assuming the measurement is RMS) should be sufficient to provide enough power. Sounds to me that the issue may be in the inefficiency of the speakers you are driving the power through or the enclosure the speakers are attached to.  Is the enclosure a mismatch for the speakers, i.e. perhaps the enclosure's cubic footage is inadequate to produce the output level when being driven by 300 watts.  Try dropping the speakers into larger enclosure and see if that changes the overall output level.  If not, look for speakers that are more efficient (as well as match up against the speaker compartment's cubic foot volume) and you will find that the output will be louder.  Pyle speakers typically work well with a small cabinet enclosure as they don't require alot of cubic footage from an enclosure perspective.

This is why the active/powered speaker cabinets are so popular and sound so good: the manufacturer takes the guess work out of it for, by perfectly "tuning" the spkr. cabinet and the builti-in amp to perfectly match eachother!

I have a pair of QSC K12's and a pair of their K10's - LOVE EM!  - - good for PA mains, or for stage monitoring... OR for a kick-ass stereo kybd. setup - as the OP is describing here.

They are not cheap but once you make the investment & hopefully sell off or trade in your older/heavier gear - you never look back!  :smiley-eatdrink003:

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