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Post by burnchar on Oct 12, 2014 10:58:36 GMT -5
I brought my XPR-5 to a friend's house since he wanted to see what his two Polk RTI-12 speakers could do.
During one test song, the XPR-5's clip warning lit on both channels.
This begs the question: Does the XPR-5 detect when a speaker is at its limits and warned of this situation, or did the XPR-5 itself hit its limits?
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Post by garbulky on Oct 12, 2014 11:19:34 GMT -5
If you are clipping that monster, then your speaker is already risking damage!
But if it appeared clipping at not insane levels of power, there may be a short or the speaker it self has hit the limits.
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Post by Deleted on Oct 12, 2014 11:23:42 GMT -5
Those rti's love the power I had the a9' s running with an xpr2 and they took all the power the amp had. I saw red lights on it a couple times. I ended up selling the polks for some JTR'S because they just couldn't give me what I was looking for....
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Post by novisnick on Oct 12, 2014 11:39:41 GMT -5
Put a watt meter on the amp and see what it's sucking in. If its within limits then I must agree with Gar, there's something wrong else where.
Also, you said this was at a friends house on his system, your system does not show this problem? Correct? I'd look to make sure all is properly configured at his end.
That's alot of power to clip an amp of this caliber.
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Post by Deleted on Oct 12, 2014 11:43:29 GMT -5
I don't know guys you do the math for my place I'm 18 feet from my speakers for me to get 100 db peaks it's pretty close to amp limits on those speakers.....
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Post by novisnick on Oct 12, 2014 11:52:49 GMT -5
Just trying to make sure it's not the friends system before blaming an amp that works fine in another system.
Never hurts to check twice
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LCSeminole
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Res firma mitescere nescit.
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Post by LCSeminole on Oct 12, 2014 11:55:43 GMT -5
I brought my XPR-5 to a friend's house since he wanted to see what his two Polk RTI-12 speakers could do. During one test song, the XPR-5's clip warning lit on both channels. This begs the question: Does the XPR-5 detect when a speaker is at its limits and warned of this situation, or did the XPR-5 itself hit its limits? Just curious, did you use a dedicated 20a circuit at your friends house? |
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Post by Deleted on Oct 12, 2014 12:10:18 GMT -5
I brought my XPR-5 to a friend's house since he wanted to see what his two Polk RTI-12 speakers could do. During one test song, the XPR-5's clip warning lit on both channels. This begs the question: Does the XPR-5 detect when a speaker is at its limits and warned of this situation, or did the XPR-5 itself hit its limits? What sort of levels were you listening at ? We're you running the speakers full range ? The amps don't detect speaker limits. What was going on in the song at the time when the amp lit up ? |
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Post by garbulky on Oct 12, 2014 12:28:21 GMT -5
When the crossover reaches it's limit doesn't it basicaly allow a whole lot of current through? Could this be what is causing the clipping?
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Post by burnchar on Oct 12, 2014 12:43:12 GMT -5
Put a watt meter on the amp and see what it's sucking in. If its within limits then I must agree with Gar, there's something wrong else where. Also, you said this was at a friends house on his system, your system does not show this problem? Correct? I'd look to make sure all is properly configured at his end. That's alot of power to clip an amp of this caliber. This was at a friend's house and I wish I had brought my power meter, but didn't. My system does not clip the amp, I am using Klipsch KSB-3.1's until my Ascend speakers ship in late November. With 100W RMS power handling, I think the Klipsch's would sublimate to plasma before stressing the amp.  |
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Post by burnchar on Oct 12, 2014 12:46:43 GMT -5
Just curious, did you use a dedicated 20a circuit at your friends house? No. I brought am Emotiva CMX-2 which has NEMA 5-20 outlets but strangely a NEMA 5-15 wall jack. |
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Post by burnchar on Oct 12, 2014 12:51:20 GMT -5
What sort of levels were you listening at ? We're you running the speakers full range ? The amps don't detect speaker limits. What was going on in the song at the time when the amp lit up ? We were listening at levels such that distortion became noticeable. Polk RTI-12's are rated at 30Hz-26KHz ± 3dB. "Recommended amplifier power" is 50-500W. At the speaker's rated 8Ω, this is the limit of 2-ch output according to the XPR-5 specs, but that's assuming constant impedance. |
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Post by burnchar on Oct 12, 2014 12:54:37 GMT -5
When the crossover reaches it's limit doesn't it basicaly allow a whole lot of current through? Could this be what is causing the clipping? If the Polk crossover does open the floodgates at its limits, certainly this could explain the clipping. I do not know anything about the crossover, though. The speakers are inexpensive for their size, so I suspect they have an inexpensive crossover. |
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Post by novisnick on Oct 12, 2014 12:55:44 GMT -5
Put a watt meter on the amp and see what it's sucking in. If its within limits then I must agree with Gar, there's something wrong else where. Also, you said this was at a friends house on his system, your system does not show this problem? Correct? I'd look to make sure all is properly configured at his end. That's alot of power to clip an amp of this caliber. This was at a friend's house and I wish I had brought my power meter, but didn't. My system does not clip the amp, I am using Klipsch KSB-3.1's until my Ascend speakers ship in late November. With 100W RMS power handling, I think the Klipsch's would sublimate to plasma before stressing the amp. :)J Good one with the Plasma power, that's exactly what I was using with my Klipsch KF-28 towers for power, a pair of XPR-1s and they took everything's the amps could throw at them. Klipsch make some amazing speakers that can take all kinds of power without having a melt-down. And No, Klipsch would never clip an amp with that much power.  |
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Post by deewan on Oct 12, 2014 17:14:15 GMT -5
Am I the only person who read the post and thought, "YOU MOVED AN XPR-5 TO A FRIENDS HOUSE JUST TO SEE..."  That is one heavy amp to be hauling around just because. Always remember to lift with your legs, not your back. |
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Post by garbulky on Oct 12, 2014 17:20:17 GMT -5
What sort of levels were you listening at ? We're you running the speakers full range ? The amps don't detect speaker limits. What was going on in the song at the time when the amp lit up ? We were listening at levels such that distortion became noticeable. Polk RTI-12's are rated at 30Hz-26KHz ± 3dB. "Recommended amplifier power" is 50-500W. At the speaker's rated 8Ω, this is the limit of 2-ch output according to the XPR-5 specs, but that's assuming constant impedance. If it's just the two speakers it was driving, the xpr-5 is able to push quite a bit more than its rated power in to two channels. I would look at the XPR-2's figure to see what kind of power the XPR-5 is able to deliver there. If and when the crossovers let that current through, from what I'm gathering it's damaging to the speakers. I'm not an expert in this but that's what I've read. |
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Post by bub on Oct 12, 2014 17:46:50 GMT -5
I have a PA-7 350. Basically a 7 channel XPR-5 . Same 3.3 kVa toroidal power supply and 180,000 Uf of storage. Also using Rtia9's. I think that's the newer version of the speaker you were listening to. Never had a problem. Right into distortion. I am running separate 20 amp circuits. ( I have two of them ) Nothing but blue lights. My amp is rated at 500 watts into 3 channels driven.
My suggestion. Bring your amp home and don't do that again. You must have been blasting. I did a spl reading today and I was surprised at how high it was.
And I was just listening at what seemed to me to be normal listening volume. I'm just wondering if it could be line sag? Someone questioned if you were using a 20 amp circuit. I think line sag just limits output. Someone who knows more may be able to explain it.
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Post by sct on Oct 12, 2014 19:01:19 GMT -5
>>No. I brought am Emotiva CMX-2 which has NEMA 5-20 outlets but strangely a NEMA 5-15 wall jack.<<
This means that you were effectively using a 15 amp line. The XPR-5 was not able to put out its full rated output because of this.
SCT
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Post by burnchar on Oct 12, 2014 19:43:31 GMT -5
Am I the only person who read the post and thought, "YOU MOVED AN XPR-5 TO A FRIENDS HOUSE JUST TO SEE..." That is one heavy amp to be hauling around just because. Always remember to lift with your legs, not your back. No kidding. It seemed like a good idea at the time. Then, once I was committed because all the cables were disconnected, I tried to lift it. |
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Post by burnchar on Oct 12, 2014 19:47:06 GMT -5
>>No. I brought am Emotiva CMX-2 which has NEMA 5-20 outlets but strangely a NEMA 5-15 wall jack.<< This means that you were effectively using a 15 amp line. The XPR-5 was not able to put out its full rated output because of this. SCT I know, but a 15 amp line can still saturate the XPR5's capability when powering a pair of 8Ω speakers. If the outlet was insufficient, it likely would have tripped the breaker. I don't think the XPR-5 can detect which outlet it is on since they are both the same voltage. |
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That is one heavy amp to be hauling around just because. 
