Thoughts on wireless subwoofer.

Just looking for thoughts on whether this idea might actually work!

I have an Ayre ax7e integrated amp which does not have a sub out so best connection to a sub would be from speaker terminals taking care on connections as this is a fully balanced design.
This has been discussed previously in other threads and with Almarg.
However in my system hooking up a sub like this AND alternatively using the tape out RCA resulted in a very audible ground hum especially on phono.
This I could not get rid of so abandoned the idea.

Now here are my thoughts anew.

What if there was no actual physical connection between amp and sub? Surely then I should not suffer a ground loop hum?
Started looking at wireless subs and there are a few hifi orientated brands than run of the mill HT units.
One in particular I have been studying is the Martin Logan Dynamo 700w. This has a built in receiver and uses a transmitter that accepts RCA inputs and transmits on Bluetooth to the sub.

Sounds like it should work but.....

Anybody see any downside or has actually used a wireless sub?

Thank you.
Have you considered just running a set of cables from your speakers to the sub/subs?  Your speaker terminals allow for both spades and bananas so connection will be really simple.  Of course the sub/subs must allow for speaker level input.
As I said any physical connections either from speaker terminals or RCA gave an unacceptable ground loop hum.
However speaker level connection to subs from an Ayre a7xe is anything but simple I am afraid.
But thank you!
I can commiserate about trying to hook up a pair of speakers and subs on the A7xe. Those binding posts make adding 2 pairs of cables a bit of work, but, it can be done.
Dear @uberwaltz: I have not experience with wireless subs. Now and due that your speker woofers crossover 300hz you need to use an external good quality crossover ( Bryston is an example or Pass. ) to relief the main speakers woofers from 80hz and down.
Using the speakers full range along the subs is a big mistake and not the way to go because the main target when using subs in a stereo music home audio system is to improve the IMD lowering it at much we can and when you make what I said you are achieving that critical target and then your system sound will improves in a huge way putting you nearer to the live event. You need two powered subs connected in true stereo fashion.

If the powered subwoofers comes with a good quality high pass filter then you don't need an external crossover that normally has better quality performance.

Either way you need to contact Mr. Jansen ( I think is the Ayre owner, maybe I'm wrong. ) and explain him the trouble you are experienced and see which are his advise. Maybe a new integrated amp because yours has at least 10 years was designed.

In the other side maybe the trouble could comes from a not very good subs design you have, I can't know for sure.

Regards and enjoy the MUSIC NOT DISTORTIONS,
Thank you
Unfortunately I have already ordered a Martin Logan Dynamo 700w sub.

But I do see your point exactly on cutting the lower freq to my main speakers as you would in a ht rig with small sat speakers say.
I can see how the combined low freq from both the mains and the sub may make it harder to integrate the sub seamlessly.

I did speak to Ayre before pursuing this and part of the problem is the way the ax7e is built as a fully balanced unit and it just doen not play nice with some subs depending on THEIR grounding design.

There has been a couple of important threads on this previously which Almarg was kind enough to make me aware of. If he had not and I had just connected a sub up using the speaker terminals as common practice would have you do so I could have actually seriously damaged the Ayre internally.

See this...

So I will try the wireless approach although it does mean I have full output at the tape loop output but I could likely find a unit to insert inbetween that that would turn it to a variable output. Only just thought of that and I am sure something must already exist for that function, to take a fixed rca output and give you the option to vary it. Google search time!

But thank you Raul.

Hi Uberwaltz,

I’ve just noticed this thread. Thank you kindly for the mentions.

I’m uncertain as to whether or not the wireless connection to the sub you’ve ordered will work ok or not. I see that the wireless transmitter is powered by an AC adapter, which I assume is a wallwart type of device. So depending on its design, and perhaps on whether it has a three-prong AC plug or a two-prong plug, there may or may not be a ground loop issue or some other ground-related issue arising between it and the Ayre. If there is, and as a result the transmitter sees a hum component on its RCA inputs, presumably it would faithfully transmit the hum to the wireless receiver.

Should that occur, though, I’m thinking that a line-level audio isolation transformer connected between the Ayre and the wireless transmitter, or perhaps even between the Ayre and the RCA inputs on the sub itself, could very well be a solution.

At a low price point ($60) this may be a solution:

Its datasheet:

A Jensen transformer may also be a solution, albeit at a higher price point (~ $250):

Hopefully neither of those things will prove to be necessary, though. Looking forward to your findings.

Best regards,
-- Al
Thanks Al!

Should be here next week and then we will see what occurs.

I am sincerely hoping it is not that efficient that it faithfully passes on the ground loop

The ac transmitter will be plugged into the back of my Equicore 1800 whether that will help or not remains to be seen!

Will update later!
Well for once my thoughts and a plan actually panned out perfectly in real life practice!

Sub online via a Bluetooth transmitter and absolutely no ground loop hum at all on any input.

And with it being a 10 inch sub it is fairly tight and musical and able to use as a variable input and tailor its frequency response so it is dialed in and for once I would say it is near impossible for me to detect actual sounds coming from the sub itself.

But it has done its job exactly as I wanted and nicely just filled in the very low end that my 2 way Devores could not.

Even a blind squirrel finds a nut once in a while!
Great news, Uberwaltz, and congratulations!  And a great quote about the squirrel.  I'll have to remember that one for my own purposes :-)

Best regards,
-- Al 
Thx Al.

It used to be a favorite saying of a work colleague whilst troubleshooting electrical maintenance issues in factories.

A very skilled technician but always modest, a rare commodity nowadays.

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