# Seeking MiniDSP 2X4 balanced expert for 2 sub setting



## apilon (May 18, 2006)

Good morning 

I just finished building a second Micro Marty with the Dayton RSS390HO driver. The first one uses TC Sound LMR-15 I also bought a used EP2500 to drive the second Marty.

BEcause i need to rearrange my HT configuration i stacked the Micro Marty on top of the first one. After connecting to the output no 2 of the Minidsp and setting up the HPF to 23Hz i proceed to testing and found that the sub output was someone lower than before so i shut one of the sub amp and the repeated the test sound level was loud with only one sub but diminished when both were playing 

Took out my RS sound meter tested the first sub (tc sound) level was 70-72db) tested the dayton sub level was at 76 db tested with both playing level was at 70 -72 db. ARC calibration was off when testing so not sure if it is ok . 

What do you expert think? Should i use the minidsp output to level the sound of the dayton to 70db to match the level of the tc sound and calibrate or is it the fact that both sub are stack on tp of each other that have an effect on sound level 

Thank you for your input 


Alain


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

If both subs are using different drivers and their own separate amplifiers of different brands (you didn’t tell us what amp is driving the first sub), there’s no reason to expect that their initial outputs would be the same. Adjust gains as needed to match the levels, that’s what they’re there for. :T

Aside from that, since the level drops with both subs playing, that suggests a polarity issue. With an unbalanced signal path, this is usually just a matter of verifying the polarity of the speaker connections. However, in your situation, using balanced connections with multiple (I assume?) bridged amps, there are lots of places for this to happen, including the signal input connections as well as the speaker outputs. Thus go back and make sure you have all the wiring (+) to (+) and (-) to (-) on both the connections between the miniDSP and the amplifiers, and the amplifiers to the speakers. If the amps are bridged, make sure all setting are correct and the designated inputs used.

Regards, 
Wayne


----------



## apilon (May 18, 2006)

Wayne A. Pflughaupt said:


> If both subs are using different drivers and their own separate amplifiers of different brands (you didn’t tell us what amp is driving the first sub), there’s no reason to expect that their initial outputs would be the same. Adjust gains as needed to match the levels, that’s what they’re there for. :T
> 
> Aside from that, since the level drops with both subs playing, that suggests a polarity issue. With an unbalanced signal path, this is usually just a matter of verifying the polarity of the speaker connections. However, in your situation, using balanced connections with multiple (I assume?) bridged amps, there are lots of places for this to happen, including the signal input connections as well as the speaker outputs. Thus go back and make sure you have all the wiring (+) to (+) and (-) to (-) on both the connections between the miniDSP and the amplifiers, and the amplifiers to the speakers. If the amps are bridged, make sure all setting are correct and the designated inputs used.
> 
> ...


Hi Wayne 

Thanks for responding The ep4000 is driving the TC Sound LMS-R 15 and the EP2500 the Dayton RSS390HO both are using the same cabinet (the micro marty)

I tried reversing the polarity with the minidsp but it changes both channel ( 1 &2) at the same time and i did not noticed any improvement. I will verify every connection again making sure that polarity is good. the way i am connected right now is avr sub out --- to minidsp in #1 -- minidsp out #1 to in xlr ep4000 -- speakon out ep4000 -- sub .......then minidsp out #2 to in xlr ep2500 -- speakon out ep2500 to sub 

Thanks again


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Don’t forget to take apart the Speakon connections and verify that they’re wired correctly on _both_ ends (amp and sub side). As you probably know, with a bridged output the speaker cables’ ends _can’t_ be reversed. Also verify all your dip switch settings. Like I said, with your set-up there are a lot of places for things to go wrong. :T

Regards, 
Wayne


----------



## apilon (May 18, 2006)

will do speakon is suppose to be +1 +2 on the side of the bridged amp and +1 -1 on the sub side

thanks again


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Yes, with 1+ being speaker + on the amp side. :T

Regards, 
Wayne


----------



## apilon (May 18, 2006)

Hi Wayne 

One quick question for you.......I am almost done checking the wiring polarity and i even switched the ep2500 with another ep4000for the second sub to make sure it is not an amp problem. 

While i was validating the dip switch setting in the manual of my QSC RMX850 which drive my center channel i read that in order to lower floor noise and hiss sound one should tuen the volume of the input source as high as it allow and use the amp gain to control the loudness of the volume to achieve 75db 

So that would mean setting up the receiver volume at 0db reference . Does that statement makes sense?

Alain


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Yes, high input signal to low amp gain setting is best if that can be accomplished – basic gain structure protocol. Not necessarily as high as the input signal gain adjustment will allow, because at max it will probably be clipped, but as high a clean signal as you can get.

Regards, 
Wayne


----------



## apilon (May 18, 2006)

Thanks


well i have unplug verified and plugued back everything and now i do not get any sound from the 2 sub. first test i did bypass the minidsp and connecedt the sub directly to amp all sub work fine reconnected minidsp no sound rechecked all minidsp connexion so rca from receiver to red plus on minidsp and shield conneted along with jumper to neg input 

output 1 and 2 positive , negative and shield connected to input xlr of amp 

it was working prior to unplugging everything ..then decided to plug in output of minidsp to center channel and got very faint sound but sound normal when direct 

i resetted the minidsp a few time nothing improve i am scratching my head here trying to figureout what the hell is wrong 

please someone help i am starting to regret that purchase


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

A bit hard to follow your signal flow, but if you’ve double-checked all connections and polarity as I discussed in Post #2 it should work. Have you posted your issues on miniDSP’s Forum?

Regards, 
Wayne


----------



## apilon (May 18, 2006)

i tripple check every connexion all is according to manual yes i posted on minidsp forum awaiting reply


----------



## apilon (May 18, 2006)

well problem solved. seem to be a power supply issue and software config 

i had tested the power supply and it registered 12v but somehow the minidsp did not like it. found one with 2a output and tada ....

also resetting the minidsp while not connected to the avr and amp seems to do a better job of clearing the old config

so now both sub are playing loud as they should

Alain


----------

