Clipping led flashes on my proamps

[Eyecantcode]

Hello all, this is a quote from a thread over at another forum and I was wonder if you guys would be able to lead me som insight on my inquiry:

I have an 1121, Pl-89's Pl-28, surrounds, xls1500, and a MA2050. The Acoustechs look and sound great, but I can't say that I can tell a difference in sound from the tsi 300's. Although I haven't tried the acoustechs connected to the reciever, I do believe the amps make a big difference. I have no problem with movies, music now thats another issue. While playing music in 2-channel at reference levels, I noticed the clipping led flashed a couple of times. I was under the assumption that at 300rms the amp wouldn't come close to clipping. I originally had the pl-89's on the crown, then I tried them on the marathon and the samething would happen listening to 2-channel music at reference levels. Of course I turned the gain down on the amps, but the sound levels drop. Since my ears aren't bleeding, I want more. I was hoping with a little help from you guys I would be able to tweak my system and get ear bleeding results. Let me know what info I need to provide

I was wondering if an ep4000 would help with the clipping while listening to music. Would my speakers be in any danger from the ep4000?

 

[TLS Guy]

Hello all, this is a quote from a thread over at another forum and I was wonder if you guys would be able to lead me som insight on my inquiry:
I was wondering if an ep4000 would help with the clipping while listening to music. Would my speakers be in any danger from the ep4000?

To consistently produce reference levels (live performance peaks,especially for classical music), with speakers of average sensitivity in a 12 to 20 ft plus room with 8 to 10' ceilings requires about 2000 to 4000 watts and speakers that can handle it. That is the only guarantee I know of to avoid clipping. The other solution is higher sensitivity speakers. every 3 db increase in sensitivity halves the amplifier power requirement.

 

[Eyecantcode]

So basically, what I'm experiencing would be expecting given the source being 2-channel music. So getting an EP4000 wouldn't benefit me in any way?

 

[TLS Guy]

So basically, what I'm experiencing would be expecting given the source being 2-channel music. So getting an EP4000 wouldn't benefit me in any way?

I checked the specs of your pl89 and their sensitivity is 98 db! So they are high efficiency and an amp of 200 watts per channel would be more than enough, in fact 100 watts would do. However I suspect they may have a difficult impedance curve and probably phase angles if they are clipping your amp. They are specified at 8 ohms, but they can't be, they must be around four or less in the bass.

If you select an amp that will deliver 100 watts into 8 ohms and 200 watts into four ohms, I bet it will not clip driving those speakers without deafening you.

 

[Eyecantcode]

With that being said, the crown xls1500 is rated at 525wpc @ 4ohms and the MA 2050 is rated at 500wpc@ 4ohms So I'm not sure why clipping would even be an issue. I'm thinking maybe I have a setup issue or maybe its just me. I've heard people using an xls 1000 ,1500 for driving subs (without mentioning clipping) which is way more demanding on an amp than mains set to small and crossed over at 80hz. Am I missing something?

 

[TLS Guy]

With that being said, the crown xls1500 is rated at 525wpc @ 4ohms and the MA 2050 is rated at 500wpc@ 4ohms So I'm not sure why clipping would even be an issue. I'm thinking maybe I have a setup issue or maybe its just me. I've heard people using an xls 1000 ,1500 for driving subs (without mentioning clipping) which is way more demanding on an amp than mains set to small and crossed over at 80hz. Am I missing something?

Please make it clear exactly which LED is clipping on what and when. Something is not making sense here.

 

[Rickster71]

As TLS uncovers and rules out more about your speakers and amp, it gets me wondering about the circuit your equipment is on. I'm starting to suspect a possible voltage drop.
Is it a dedicated circuit, if not, what else is on it, including other rooms?

 

[Eyecantcode]

As TLS uncovers and rules out more about your speakers and amp, it gets me wondering about the circuit your equipment is on. I'm starting to suspect a possible voltage drop.
Is it a dedicated circuit, if not, what else is on it, including other rooms?

It's not on a dedicated circuit for sure. When I get home from work I'll trip the breaker and see what all goes off. What I do know is I have an xls1500, MA2050, 1121, WD 60638, living room lights, and 2 BIC VF 12's.
@TLS - when I get home I'll see exactly, but I know it has a white, yellowish, and two reds and the first red led is the one that flashes.

 

[walter duque]

Might be what Rick states, a voltage drop. What is the power consumption of your amp at max. power. Now I have one power amp 350 watts 8 ohm, 500 watts 4 ohms X 6 which needs 5800 watts at max. power. Now I run my whole system of a 15 amp breaker and my amp I can drive into clipping. Amp shuts off at times or breaker trips. Now wired at 220 volts with dedicated breaker, no problem, no clipping. I would need a 50 amp breaker just for the amp.

 

[Eyecantcode]

I guess I could use my multimeter to test the current at the point the clipping occurs, but other than that I'd have go by the specs to know the power consumption. I'm not an electrician so I'm clueless *** to how to dedicate a separate breaker or wire an outlet to 220v. Is this an expensive task?

 

[Eyecantcode]

Speaker show 3ohm when they are rated @ 8 ohms

I am determined to get to the bottom of this clipping issue. I checked the impedance of my pl 89's and my pl 28 and all three are reading 3ohms instead of the rated 8ohms The ma 2050 and xls1500 claim 500wpc(probably more like 400) @ 4ohms but the acoustechs have a rms of 250w. Can this be the cause of the amp red clipping LED flashing?

 

[GO-NAD!]

Could it be a gain issue? Perhaps your AVR doesn't have the output voltage to properly drive a pro amp?

 

[walter duque]

I assume your system is calibrated. Are you clipping when you set your Pre-amp at 0 db. Mine starts clipping very slightly at +6 db.

 

[Eyecantcode]

I've calibrated my system, but I plan to run mcacc again when I get home. I first notice the clipping LEDs at -5. Is it not a concern that my speakers that are rated at 8ohm are reading 3ohms?
Walter, what amp and speakers are you referring to?

 

[walter duque]

I've calibrated my system, but I plan to run mcacc again when I get home. I first notice the clipping LEDs at -5. Is it not a concern that my speakers that are rated at 8ohm are reading 3ohms?
Walter, what amp and speakers are you referring to?

This Product Review is my 15 year old beast. Speakers are from this Floorstandinglist company and are rated at 6 ohms.

 

[Eyecantcode]

Wow, you can drive that thing into clipping? Is this during movie or music? Then maybe I just have a misunderstanding of what's going on. Still, how can someone drive subs with the amps that I have and not have clipping, but I'm driving towers set to small and crossed over @ 80hz and my clipping LED flashes. I just don't get it.

 

[Irvrobinson]

To consistently produce reference levels (live performance peaks,especially for classical music), with speakers of average sensitivity in a 12 to 20 ft plus room with 8 to 10' ceilings requires about 2000 to 4000 watts and speakers that can handle it. That is the only guarantee I know of to avoid clipping. The other solution is higher sensitivity speakers. every 3 db increase in sensitivity halves the amplifier power requirement.

And to think in another thread I'm arguing with DS-21 about whether I need 70 watts or about 250-500 watts to avoid clipping on my mains of very average sensitivity. (I'm guessing the larger number.) And my room is a lot larger than the example you're using. I think I'll refer him to you.

 

[Rickster71]

Is it not a concern that my speakers that are rated at 8ohm are reading 3ohms?
Walter, what amp and speakers are you referring to?

The method you used is OK for a 'ballpark' measurement of ohms.
A true reading varies with the frequency, and needs more equipment to do accurately.
Since many 8-ohm speakers (measured nominally) dip below 4-ohms, your measurement of 3-ohms sounds about right.
Is there any chance the speakers are hooked up out of phase? To help narrow things down I'd recheck the polarity of all your connections.

 

[walter duque]

And to think in another thread I'm arguing with DS-21 about whether I need 70 watts or about 250-500 watts to avoid clipping on my mains of very average sensitivity. (I'm guessing the larger number.) And my room is a lot larger than the example you're using. I think I'll refer him to you.

My room is around 18'x14', if that much.
Front section

Rear section

 

[Eyecantcode]

The method you used is OK for a 'ballpark' measurement of ohms.
A true reading varies with the frequency, and needs more equipment to do accurately.
Since many 8-ohm speakers (measured nominally) dip below 4-ohms, your measurement of 3-ohms sounds about right.
Is there any chance the speakers are hooked up out of phase? To help narrow things down I'd recheck the polarity of all your connections.

Well I thought speakers would dip below their rated impedance during use, my read 3ohms while unhooked. Don't know why the state 8ohms if they read 3ohmish. Not sure about the out of phase part, but I'll recheck the speakers polarity connection. With everything that's been said, do you guys suspect there's a problem?