Peter P.

That's a user-installed protection fuse. One speaker wire connects to the nut on the right hand side, the other speaker wire connects to the left side terminal. A simple method of protecting your speakers if you desire. I'd guess a 3 or 4 amp fuse, assuming 8 ohms and 100 watts.

I think it's your father in law that has gone off the deep end. You probably like the Heresies because they're affordable. I'm sure the LaScalas and the Klipschorns just plain fill you with envy! In my opinion you're over-thinking things. ANY amp will do but it audio-world, we can't help but equate quality sound with the dollars spent, which is how subconsciously you're trying to compete with FIL. Hook your Heresies up to any modern amp even so-called budget amps like Yamaha or NAD and listen to the music, not the equipment. For perspective, my car audio system is a $100 Sony receiver that accepts a USB/iPod input, four Boston Acoustics 6 1/2" coaxials, and an SAS Bazooka 6.5" subwoofer running from the Sony's line level subwoofer outputs. Those USB files sound awesome.

The OP can definitely use the speaker level outputs to drive a subwoofer. The limitation is now only lower cost subwoofers come with speaker level inputs. With the OP's $500 budget for a subwoofer, I'd suggest checking the used market i.e., craigslist or facebook marketplace. I wouldn't look on eBay because shipping costs will be excessive due to the weight of a subwoofer. I suggest the OP tell us what area they live in and we can peruse the web sites to see if there is anything of good value. $500 on the used market can buy a very good subwoofer.

If you hear sound, the sub is working. Sounds like (no pun intended) the LED went bad.

How did you verify that is where the problem is? Help us eliminate possible causes by detailing your troubleshooting steps and telling us what you've already tried to remedy the problem.

According to the manual, you have to select Small in the "Manual SP Setup - Speaker Setting" menu to send a signal to a subwoofer. If it's set to Large the receiver will not send a signal to a subwoofer output. Is your setting correct?

That amp has no means of high-pass filtering a signal to the main speakers.

Not necessarily. But the kg 1.2 does play lower than the R-41M which might be more easily pushed to its limit when played louder. That would not be an issue if your Denon amp has a high pass filter, limiting the low frequencies sent to the main speakers. Most home theater amps and receivers have this feature and would be ideal for your application. That would even be a good idea for the kg 1.2s as they wouldn't be over-driven trying to reproduce those bass notes, assuming you pair them with a subwoofer. If your amp does NOT have such capabilities, you can always make a cheap high pass filter to limit what goes in to those smaller, main speakers. Here's what I did to provide a high pass signal to my Klipsch Heresies. I bought a high pass crossover, one for each speaker. Bought a pair of small plastic project boxes, some spade connectors, and some speaker wire. I can easily disconnect them if I wish, and replace the high pass filter with a pair of homemade pigtails to return the speakers to full range if I want. The crossovers are held in place with double sticky tape or Velcro. Here's a crossover I would suggest. Here's a box to fit. You'll need both male and female crimp connectors, too- 10 female (8 for the crossover and 2 for connecting to your speaker wires.) You need a pair of male connectors to put on the speaker wires. You'll also make a pair of pigtail wires if you want to remove the crossover from the circuit. A basic pair of combo wire strippers/crimpers will do the job. Five to ten feet of 18-16 gauge wire. Except for the crossovers and the boxes, you can buy the rest from your local hardware store.

Since you're going to have a subwoofer fill in the low end, you could get the R-41M even though it doesn't play as low as the kg 1.2; the subwoofer will cover the missing Hz and you won't notice a difference. New speakers don't come with the nicks, scratches, and wounds of used speakers, which sometimes makes buying new worth it. Also, the kg 1.2 comes in a real wood veneer vs. a woodgrain vinyl. I'd pay the premium for a used pair of kg 1.2s if having a speaker that plays lower is of value to you.

Is one speaker wired out of phase? Try reversing the wires connecting to one speaker. It's also possible one of the individual bass drivers is wired out of phase with regard to the other bass driver in the same cabinet. Poop happens at the factory. To confirm the drivers are actually moving, it's okay to put a finger on the edge to verify. Do this with all four woofers. Does the music you're playing have large bass content?

The Chorus IIs play considerably lower than the Heresy IIIs and I believe you'll notice the difference. Efficiency is close to equal. I'd say go for it.

I don't know what you mean by "lay them down end to end" but you have to live within the limitations of your listening space. So place them within the limits of your room and enjoy them. They'll only distort if overdriven or if the amp clips. Your ears will be ringing long before then!

Of course it's a good setup. You have to work within your space limitations, and you have.

What Schu said. I can't really follow how you wired them from your receiver, but you need to verify that the "+" terminal on the receiver goes to the "+" terminal on the speaker. Actually, all that matters is that however you wired the left match speaker matches the right speaker. If you don't, your bass frequencies will sound weak. Report back after you've checked the wiring.

You're looking in the wrong place for improvement. Two words: Room acoustics. While you can't change a room's dimensions, you can change its acoustic properties. Considering the equipment you have, I'd say you have the funds to hire a consultant to analyze your listening space and suggest improvements.