I have two subs in my setup. Here's the wiring scheme: Sub out on my 1070 is wired to my SuperNova's "Left In" RCA jack. The interconnect is a simple, no-name brand standard audio cable. It's actually pilfered from the fairly heavy feeling cables that Comcast brings out when they do a new STB installation. It's about an 8 ft cable.

I run a standard Acoustic Research "actual sub cable" from the "Left Out" on the SuperNova, into the basement, and back up through the floor to my Fathom F112. It's a 25 ft cable.

I had calibrated my Fathom connected directly to the 1070. That was possibly a mistake. I'm not sure.

Problem: I noticed the other day, I thought the Fathom was a bit quiet listening to a certain piece of music. Generally when the 2 subs have their master volume set to around the same position, I notice that the SuperNova is much louder than the Fathom. This is not what I would expect. The two subs are each in a corner of the room.
As a mini-experiment, I removed the Supernova from the equation and ran the 25 ft AR sub cable straight into the 1070. I realized a fairly significant gain in the output from the Fathom. (I can't be 100% sure if this is my ears, something with the acoustics of going from 2 subs to 1, I don't know.) The Fathom seemed to wake up and the output was much cleaner than the Supernova (no surprise there.) I actually contemplated leaving just the Fathom in the config but I do like the more even distribution of the bass with two subs.)


If there is a real issue with the daisey chained config, I can only guess it's one of three issues:

1.) The Supernova manual recommends using a Y adapter (1F/2M) at the sub to split the single sub cable coming from the receiver, for "optimal performance. Perhaps me using only the Left In is somehow cutting out some of the signal as it's passed on to the Fathom? There is a Right Out (as you might suspect) next to the Left Out that I'm currently using. I could potentially pick up a Y adapter to fill both INs on the Supernova, and another 25 ft sub cable, run the two cables to the Fathom, and then merge them back to 1 M RCA before hooking up to the Fathom. (JL recommends only using a single sub in.)

2.) Less likely, the "el-cheapo" sub cable I'm running to the Fathom is causing part of the problem? (Side question: In general, am I jipping myself using a standard off-brand audio cable to send the signal to the Supernova? I'm unsure of the difference between a standard audio interconnect and a "sub cable"). I have no humming issues as it stands.

3.) Possibly the Supernova's pass-through is just lousy and I should be running the JL as the Master in this config...

There's lots of things I could see being an issue and it could be a combination of things I guess. I have about $200 burning a hole in my pocket and I'm interested in fixing this issue before addressing other cable upgrades. Any suggestions would be greatly appreciated (as always.)

Thanks!

oh and one other thing - if anyone wants to critique my choice of cables, I won't be offended. I'm already reading some things about the standard AR cables that make me think spending $150 at BlueJeans for new sub cables, Y adapter, and new L/C/R speaker cables would be money well-spent. All advice is welcome.

Is there a reason that you can't just split the original output and run directly from the 1070 to both subs? The pass-through would hopefully be transparent, but I know nothing about the specific subs in question and so don't know if that is the way they are designed. (There could be something else in the circuit, like a crossover network or such, that would have an effect.)

Also, I would expect each sub to have different output levels when their volume knobs are set to the same position - there are too many differing factors (amplifier being used, efficiency of the driver and its respective enclosure, placement in the room, ...). You should probably adjust their volumes by running each by itself and adjusting the volume controls so they achieve the same output level.

Gonk - one thing I didn't mention was that when testing the Fathom as slaved, even with the volume all the way up, it wasn't "THAT" loud - loud but not overpowering, and overpowering is what I would've expected with the volume maxed out on the sub (and the 1070's channel calibration set to 0.) This was part of what set off a red flag to me, that the Fathom might not be getting a good signal.

My understanding of the Fathom is that the passthrough is/should_be transparent. However, my ears tell me something's up.

So with your suggestion, I could Y adapt right at the receiver, send one cable to the supernova and another to the JL. I'd use another Y at the supernova per the manufacturer recommendation. I like it. I think that's what I'll try.

That sounds suspicious to me, as well.
You mean the Supernova's passthrough, right? Since you are going through the Supernova to get to the Fathom?
Right - use a Y adapter at the output from the 1070 and go straight to both subs. That simplifies the equation a bit.

Yes that's right, typo on my part. Thanks again!

So what are your thoughts specifically on the use of the comcast audio cable and standard AR sub cables? Would you personally spend the $50 on new sub cables as part of the overall tweak?

I'd delay making any cable changes until after trying the re-wiring project. If there are issues with the system afterward (such as noise that oculd be the result of a long, poorly-shielded cable), I could justify picking up a Blur Jeans cable or two, but you may find that there's no need to spend the extra money.

fair enough - thank you.