Really loud Hiss noise when connecting Sub1 and S1Pro



I have used pair of Bose S1 pro speakers for over a year now and they have been really amazing. My setup is vocal and Nord Stage 3 going to mixer and pair of S1 pro speakers have been connected to mixer main out. There have been no hiss sound and no problems until now... I bought Bose Sub1 to support the lower end and get more power on the stage. But when everything is connected and I turn on Sub1, there is really loud hiss noise coming from S1 pro speakers. Yes, it`s really hiss and its loud. 

Before I had the Sub1, my s1 pro speaker volume level was at 50% on the gigs. Now with Sub1 I can only turn volume level up to 25% and then it already starts hissing. But using S1 Pro speaker volume level at 25% is way too quiet on stage.

If I turn of sub!, the hiss sound disappeare, when turn it on hiss is back. All the cables I use are balanced and really good quality. 

I even get the hiss if there`s no input connected to the Sub1, but S1 pros are connected to Sub1. So it`s definitely coming from Sub1. Everything on my setup has connected correctly as they should be.

Is there a way to reduce this hiss sound or is it something I just have to get used to?

Is there a possibility that Sub1 signal is too powerful for S1 pro speakers? 

I am using XLR to 1/4 inch (6.35 mm) Tip-Ring-Sleeve cables to connect s1 Pros to the sub.

I`ve tried different cables etc. Is removing the battery from S1 Pro can reduce hiss sound?


Thank you!



Hello Ragnar H,


Sorry to hear you're having a hiss problem using your Sub1 and S1 Pro's.


Are you located in the US?  The reason I ask is that another user experienced a very similar problem, except they had a "hum" instead of a "hiss".  They were located in France.  I'm not saying this is the same symptom, so the diagnosis may turn out to be different.


I know the AC voltages and frequencies vary from country to country, but recent Bose equipment is supposed to have universal internal power supplies.  I know that in the US, it is wise to make sure all the equipment is connected to the same circuit, and with proper grounding in place, to avoid "ground loops."


Perhaps a Bose mod can jump in here, but I think it may be best to contact Bose directly to discuss.


The Bose US support line is 877-335-2673.  For contacts outside the US, visit this page.


Does that help?

It’s not hissing, it is that the signal is just too loud. The signal coming from the sub is way too hot. I have the same issue. As a matter of fact it isn’t an issue, it’s just how it works. If you hook up your S1’s to a sub1 or a sub2 or any other sub (I tried with an EV200, same thing!) using balanced cables you must turn down the volume on the S1. It actually says so in the instruction manual. There isn’t a line/mic switch on the S1 channel mixer so channel 1 and 2 are set to mic as standard and as such are way too hot for a balanced signal coming from the sub. Don’t ask me why there’s no problem without the sub I have no idea. Try with unbalanced TS cables and the problem will go away (weirdly enough Bose recommends unbalanced cables from sub to s1)