Sub changes HSTs Nearfield ds4’s ported - Page 20 - AVS Forum | Home Theater Discussions And Reviews
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post #571 of 580 Old 10-04-2018, 06:56 PM - Thread Starter
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So back to my issue with amp hiss. It still has some unwanted noise in the subs. But I narrowed it down to the fact that with only one amp connected to the mini dsp, it’s dead silent. Dead. Silent. But as soon as I hook up the other amp to the mini dsp, there’s amp hiss in the speakers. I discovered this with the gains way up so I could hear what was going on. I plugged both amps into the same outlet just to see if it would go away, but it didn’t. So now I’m wondering, is there a special rca wire I can get that will isolate the amp from the mini dsp and pass the signal? Or is there an issue with the dsp? I’ve tried 50 different combinations of things plugged into different places and even grounding the chassis together and to the avr like the old inuke trick. Nothing helped. Only unplugging the second amp from the mini dsp completely solves the noise.
Any suggestions?
In this pic you can see I have a lot going on back there.
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post #572 of 580 Old 10-04-2018, 07:51 PM
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Quote:
Originally Posted by Jk7.2 View Post
So back to my issue with amp hiss. It still has some unwanted noise in the subs. But I narrowed it down to the fact that with only one amp connected to the mini dsp, it’s dead silent. Dead. Silent. But as soon as I hook up the other amp to the mini dsp, there’s amp hiss in the speakers. I discovered this with the gains way up so I could hear what was going on. I plugged both amps into the same outlet just to see if it would go away, but it didn’t. So now I’m wondering, is there a special rca wire I can get that will isolate the amp from the mini dsp and pass the signal? Or is there an issue with the dsp? I’ve tried 50 different combinations of things plugged into different places and even grounding the chassis together and to the avr like the old inuke trick. Nothing helped. Only unplugging the second amp from the mini dsp completely solves the noise.
Any suggestions?
In this pic you can see I have a lot going on back there.
No suggestions on my end but wanted to let you know I have my minidspHD going into 3 different amps with no issues (sub frequencies only though). No issues when I had it connected to only two amps either. Used monoprice rca->XLR cables.

I’m sure you tried this, but you tried reversing the outputs on the miniDSP, ie having the outputs from the miniDSP originally going into amp 1 instead go to amp two and vice versa? If you swap which speakers play off which amp, does the hiss follow the miniDSP output, the speakers or the amp?
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post #573 of 580 Old 10-04-2018, 07:52 PM
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This is only in the subs? And you say it's a hiss? Or is it a hum/buzz?

You can try placing a 12dB or 18dB/octave 250hz lowpass in the miniDSP on the channels you are using which will help cut down noise if it's getting picked up on the input side. But if the noise getting picked by the connections at the miniDSP outputs/amp inputs then it won't change anything.
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post #574 of 580 Old 10-05-2018, 03:02 AM - Thread Starter
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Originally Posted by mtg90 View Post
This is only in the subs? And you say it's a hiss? Or is it a hum/buzz?



You can try placing a 12dB or 18dB/octave 250hz lowpass in the miniDSP on the channels you are using which will help cut down noise if it's getting picked up on the input side. But if the noise getting picked by the connections at the miniDSP outputs/amp inputs then it won't change anything.


Thanks for the advice. I hear it as a hiss. It’s only through the subs. I also do have the low pass in place. I should say I have an isolation transformer right before the mini dsp in the signal chain. This removes all hum type noise completely. I didn’t need it with the inukes, but I do now with the clones.
And also, this isn’t real audible. I only hear it when nothing is playing. It doesn’t get louder if I crank the MV on the avr. It does get louder if I up the gains on the clones.
I guess what’s really a mind bender for me is that with just the one amp hooked up it’s so dead quiet. Even with my ear in the subwoofer cone. Then it buzzes when the other amp is connected. It’s gotta be an issue with the separate power cords being plugged in other outlets. It’s just a lot of plugs. I need to route them all better, but I need to figure out what will stop the noise first.
Thanks for the help
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post #575 of 580 Old 10-05-2018, 03:04 AM - Thread Starter
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Sub changes HSTs Nearfield ds4’s ported

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Originally Posted by rukus29 View Post
No suggestions on my end but wanted to let you know I have my minidspHD going into 3 different amps with no issues (sub frequencies only though). No issues when I had it connected to only two amps either. Used monoprice rca->XLR cables.



I’m sure you tried this, but you tried reversing the outputs on the miniDSP, ie having the outputs from the miniDSP originally going into amp 1 instead go to amp two and vice versa? If you swap which speakers play off which amp, does the hiss follow the miniDSP output, the speakers or the amp?


The only thing I’ve not tried is taking amp A (for lack of a better name) off of mini dsp output 1. That’s where I want it to stay. It for purposes of this diagnosis, I will swap it and see what happens. The thing is though, it’s not just one amp that hisses, it’s both once the noise starts. @Illini2000

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post #576 of 580 Old 08-16-2019, 06:32 AM
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Jared,

Sorry if I missed it, but what are the dimensions on the 4 subs at the front of your theater?
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post #577 of 580 Old 08-16-2019, 06:58 AM - Thread Starter
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Post 165.
30x38x20
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post #578 of 580 Old 08-16-2019, 07:55 AM - Thread Starter
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Originally Posted by NGiovas View Post
Jared,



Sorry if I missed it, but what are the dimensions on the 4 subs at the front of your theater?


30 wide, 38 tall, and 20 deep.
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post #579 of 580 Old 08-16-2019, 09:39 AM
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Thanks. I totally missed that when reading through.
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post #580 of 580 Old 08-16-2019, 12:49 PM - Thread Starter
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Originally Posted by NGiovas View Post
Thanks. I totally missed that when reading through.


No problem. I pointed you to this thread, because it also has my nearfield cab dimensions in the beginning. I hope you find some helpful info and end up with awesome subs.
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