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Boosting crossover/ rewire speaker? Protection circuit activated. (1 Viewer)

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Andrew
Alright guys i have a pair of Infinity Sm 155s being powered by a sony STR-DN1000. The volume control ranges from 0-75 and at 40-50 (depending on loudness of the song) the protection circuit turns on. While in everyday use i dont need to go higher than that, as a college student more than once i have really wished they would. :)
Some quick specs for you all. The Sony kicks out 110WPC (book claims that thats an RMS rating). and the speakers claim to be able to handle 300RMS each. So i really dont feel that's its being overpowered, im just not sure what the issue it... I will say the built in crossover control on the speaker (see my profile pic) is a little sketchy.. When you adjust them the speaker pops in and out a little. once they are set in place everything works fine though.
I thought maybe one speaker was causing the protection circuit to trip while the other was fine, so i ran one speaker at a time (i know. bad for amp. but only few sec.) and each blew at lvl42.
Im not sure what the issue is.. any help? also. the wires inside of the speaker (took out crossover and 15 to take a look around) are connected to each speaker with those crimped on push clip things (forgot name. sorry)... will that effect sound? would i be better to directly solder the wires to the speakers?
Thanks in advance guys! I love hometheaterfourm! A lot of smart people who know their stuff!
Andrew
 

John Garcia

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Andrew Harvey said:
Some quick specs for you all. The Sony kicks out 110WPC (book claims that thats an RMS rating). and the speakers claim to be able to handle 300RMS each. So i really dont feel that's its being overpowered, im just not sure what the issue it...
The power rating on a speaker is a MAXIMUM limit, aka something will expire at that point. It is not how much power they require to play.
I will say the built in crossover control on the speaker (see my profile pic) is a little sketchy.. When you adjust them the speaker pops in and out a little. once they are set in place everything works fine though.
That sounds like a loose wire. It is possible that it is part of the problem, but I doubt it. When you say "adjust them", what do you mean? Physically pulling on them causes the speaker to pop?
I thought maybe one speaker was causing the protection circuit to trip while the other was fine, so i ran one speaker at a time (i know. bad for amp. but only few sec.)
Really makes no difference to the amp if you run just one channel at a time.
Im not sure what the issue is.. any help? also. the wires inside of the speaker (took out crossover and 15 to take a look around) are connected to each speaker with those crimped on push clip things (forgot name. sorry)... will that effect sound? would i be better to directly solder the wires to the speakers?
It is doubtful that just a loose connection would cause the issue - the speaker would start to cut out before the receiver went into protect then IMO. Protect often indicates a short, so unfortunately, it sounds like something is wrong with one or more of the drivers in each speaker, most likely the tweeters. I have had speakers that sounded OK at lower levels but would distort when more power was applied - that would seem to indicate a burned voice coil (the part of the speaker that interacts with the magnet to move the driver) that isn't fried to the point of not functioning.
 
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Andrew
RMS:
Yes, i know they dont NEED all of that power. i was just stating that i wasnt overpowering them (i dont think)
Crossover crackle:
what i mean is that the two knobs for adjusting treble and midrange, when your turning them the speakers cut in and out. have to stop turning it during one of the times when the speaker is actually playing.
loose crossovers:
i took out the xovers and the wires are actually really nice. thick gauge, nicely soldered,.
connection ports:
I didnt think that was the issue, i was just curious if soldering those would help overall sound clarity.
thanks
 

John Garcia

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I see what you are saying, they have L-pads for the x-over to manually adjust them. Those do get corroded over time and that's why they make that sound, but I haven't seen that cause a receiver to short. It might be possible.
 
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Andrew
okay, is it economical to clean them or just live with it?
or even maybe jump the crossover?? can i just set it where i want it and jump those connections with a wire?
 

John Garcia

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The knobs are adjusting potentiometers that are part of the crossover, so I don't know if bypassing them will cause a problem or not. If you bypass, they are obviously removed from the circuit, so I would presume it might either remove some or all of the sound or permit full range signal through, depending on how the crossover is built. Cleaning them I don't think will be that difficult - some CAIG DeOxit or something similar should work. I used to have some speakers with this same function and had the same problem.
Any chance you have any other speakers you might test with your receiver to make sure it isn't a receiver problem? Or the ability to test at least one of the speakers on another receiver? You have them set to large no doubt (don't know if you have a sub or not), how about if you try setting them to small with the lowest crossover you can choose to see if the same problem exists. It may be that the speakers impedance drops low or they do, in fact, draw too much current for that receiver.
 
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Andrew
hmm! a lot of good thoughts there!
as for testing with another set of speakers.... i have others, but none have the ability to withstand those levels of power output.
can you explain your thoughts on setting the speakers to 'small' on the amp? what really does it do when you switch a speaker from large to small? ive never really learned that.
thanks for your continued ideas! im all about fixing these thing up, but i wasnt sure where to go next! i will buy some cleaner tomorrow and give that a shot. just spray it on??
one more thing i think you should know about my situation. :) read this posting
http://www.hometheaterforum.com/t/319931/broken-amp-repair-will-this-work#post_3915885
thanks again
Andrew
 

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