Sunfire subwoofer wireless kit

[spykids777]

Hi,

I just bought a JL audio Fathom 113 subwoofer. The place where it has been kept is away from my receiver. The only in wall sub connection in my house is speaker wire connection. I cannot run a direct connection to my sub from the receiver. The installer recommended Sunfire wireless subwoofer kit to get the best signal to my sub in this situation. Anyone has experience with this kit? any suggestions?

Thanks.

[JustinGN]

The kit only transfers CD-rate audio (16-bit/48khz) over a 2.4GHz wireless connection (commonly used by cordless telephones, WiFi, and interfered with by many common household objects), so it's not the best solution. If possible, I would use a cable snake to trace the nearest speaker wire wall terminal back to the AVR, then snake a long, insulated subwoofer cable alongside it and to the subwoofer. You could buy one long cable and some cable shrouds to run it through the wall, or do it nicely and get some RCA wallplate jacks to create a professional-looking run.

If there's already speaker wire near the sub, that's the route I'd go. If you're uncomfortable doing it yourself, it's probably a $100 to $200 contractor job to get it done professionally. Wireless really is a sort of "last resort" option in the HT world, and since you dropped at least $3k on the sub, go the distance and get a wired connection.

[spykids777]

Hi,
Thanks for your reply. If this kit is able to work with no inteference from microwave etc, is it capable of atleast transmitting all the information in the signal for the subwoofer to work atleast better than the speaker wire in the wall even if not the best like a direct connection from reciever to sub like you had suggested? HOw does the CD 16bit affect subwoofer signal quality?

[JustinGN]

That's sort of a catch-22. First, there always will be some sort of interference with anything wireless, whether it be natural interference (solar radiation, earth's magnetic field, etc) or artificial (microwaves, cordless phones), and eliminating it just isn't practical in any way, shape, or form. So assume the signal will be degraded somewhat as a result - that's fine, since any manufacturer worth their salt is building in error checking to the signal. The downside is that this induces further latency into the signal, latency already present due to the lossy transmission wireless inherently has (Even two wireless devices only inches apart have some loss of information during transmission - this is also why your remote control or IR blaster "blasts" each code five to ten times in succession, just to ensure the receiving device gets the signal).

So first, you have interference and latency that occur naturally with wireless signals. Then, you lump in all the other stuff, such as household appliances, cordless telephones, Bluetooth signals, etc, which adds further interference to the signal. The manufacturer adds in error checking to correct for this, but this introduces additional latency. And on top of all of this stuff, it's still a wonder it can get a 16-bit, 48kHz signal out; 24-bit soundtracks are out of the question, as are any soundtracks above the 48kHz sampling rate, since there's already too much interference and overhead in the signal.

That said, we're dealing with a (very expensive) subwoofer here, not a full range speaker. So the theory goes that since subwoofers have a lower and smaller range of frequencies, this should be plenty of room for data. Except there's a teensy problem here as well: the DAC. Before data is transmitted wirelessly, it must be encoded into Digital again, then decoded back into analog before being pumped into the subwoofer. This puts the quality of the DAC into question, as a subpar DAC could miss or remove data, as could a subpar ADC (Analog to Digital Converter). Let me draw a picture:

The typical audio chain looks like this:
Source -> Digital Audio -> Receiver/Processor -> Analog Audio -> Subwoofer/Speaker

Now let's toss that wireless kit in:
Source -> Digital Audio -> Receiver Processor -> Analog Audio -> Analog-To-Digital Converter -> Digital Audio -> Wireless Transmitter -> Wireless Receiver -> Digital-To-Analog Converter -> Analog Audio -> Subwoofer

See how it gets much more complicated? And as with any object, the more pieces it has and the more complicated it is, the bigger the risk of failure and the harder it is to fix.

Finally, you asked about signal/sound quality. 16-bit/48kHz is roughly equivalent to a CD (most CDs are 16-bit/44.1kHz), and equivalent to most DVD soundtracks (16/48). Blu-Ray soundtracks, however, tend to be 24-bit/48kHz at minimum, with an increasing number running 24-bit/96kHz thanks to the added disc space. Even at 24-bit/48kHz though, your wireless kit can't transmit all of the data in its entirety to the subwoofer - at some point, it'll have to convert the analog waveform of 24-bit/48kHz to 16-bit/48kHz, and eliminate entire pieces of the soundtrack. If this were a $150 kit for a $500 subwoofer, you probably wouldn't miss it, but with your Fathom 113, it has the capability to bring out every last detail in a soundtrack from just about any source. Putting a wireless kit on it would be the equivalent of using tires from a Toyota Prius on a Formula 1 car - you may have tons of power, but you wouldn't be able to make use of even half of it.

Since it's a Sunfire wireless kit, it will undoubtedly cost around $200 to $350 at minimum (I'm not saying Sunfire is overpriced, I'm just saying that we're talking about some nice equipment from a nice manufacturer, and that's probably a ballpark estimate on my part). For that price, you could get a Custom Installer in to run the necessary subwoofer cable to that same speaker wire terminal already near the sub, and from there you could wire it in properly.

[spykids777]

Thank you so much for your detailed explanation. 8)