Wireless Subwoofer?

[stupidvillager]

I'm looking to add two wireless subwoofers my theater. I have a Cinema 50 with two wired subs in the front. I'm wondering if I could use something like this wireless sub kit and connect sub3 to left and sub4 to the right. Or would I need two kits?

 

[tengiz]

Yes, just one kit would do it.

However, while digital wireless sub kits seem very convenient, the transmission delay that they add can be significant (15-30 milliseconds). In many cases, this delay can prevent proper integration of your wireless subwoofers with the rest of your audio system.

For instance Denon/Marantz receivers have a limit on the maximum sub distance (equivalent max delay is about 20ms give or take), and if you add the transmission delay to the low pass filter delay and the actual physical distance between the seating position and the wireless subs, the total delay may exceed the range that the receiver can handle and the wireless subs will not be properly time-aligned.

 

[Chrispy]

If your subs are equidistant one kit might do it, but if you need the separate sub setup the avr can provide, then two kits would be in order. I've got a pair of subs with wireless receivers and got two transmitters but used them several times with a single transmitter when equidistant or just a single sub pre-out....

 

[Keith_W]

Yes, just one kit would do it.

However, while digital wireless sub kits seem very convenient, the transmission delay that they add can be significant (15-30 milliseconds). In many cases, this delay can prevent proper integration of your wireless subwoofers with the rest of your audio system.

For instance Denon/Marantz receivers have a limit on the maximum sub distance (equivalent max delay is about 20ms give or take), and if you add the transmission delay to the low pass filter delay and the actual physical distance between the seating position and the wireless subs, the total delay may exceed the range that the receiver can handle and the wireless subs will not be properly time-aligned.

That is an interesting insight. Is the transmission delay constant, or does it vary every time you turn on the sub? If it was constant, I could deal with it. But if it varies, it would be impossible. I am considering adding a 3rd sub to my system. There is a convenient power point nearby, but I do not want to run audio cable to it across the floor. That is what is putting me off the idea.

 

[stupidvillager]

Yeah, I think I will just have to deal with it as running wire is really not an option. Thanks for the the clarification

 

[tengiz]

That is an interesting insight. Is the transmission delay constant, or does it vary every time you turn on the sub? If it was constant, I could deal with it. But if it varies, it would be impossible. I am considering adding a 3rd sub to my system. There is a convenient power point nearby, but I do not want to run audio cable to it across the floor. That is what is putting me off the idea.

I found the delay to be predictable and practically constant, at least for the wireless sub adapters that I tried (Martin Logan, SVS, OSD, and a few no-name adapters that claimed to be "low-latency"). In the end, I gave up and pulled balanced audio lines for my subs and was finally able to correctly time-align them.

The delay is caused by the digital transmission that uses frame buffers and needs to account for the possibility of retransmissions, ensuring that the delay remains constant even when some frames get dropped or corrupted.

This means that a good old analog RF audio adapter with amplitude/frequency modulation would be able to achieve near-instant transmission, but all the digital advantages would be lost. There would be no automatic link establishment, no band negotiation, no error correction, no RF noise isolation, etc.