Home Theater Pass Through (1 Viewer)

[BruceD]

Gorden,

Yes, I agree with chung, your wiring setup appears correct. I was simply using the analog-out term to make sure nobody mistakes it for a digital output. You're right, pre-out and analog-out are the same.

Regarding crossovers, what is the size of your room and what is the -3dB of your B&W 7NTs?

My room is somewhat less than 3000ft3, and my mains are -3dB at 32Hz. In my case I used the Marchand XM9-L with the crossover set @60Hz (about an octave above my mains -3dB spec).

What you can do is buy a number of different crossover DIP resistor sets (they're cheap) at different frequencies (like 50, 60, 70, and 80Hz) so you can experiment for the best fit.

You must also remember to get into your Denon 4800's speaker setup menu and set the sub to SUB=NO, with nothing plugged into the sub output jacks of your Denon. It's also true that your mains need to be set to MAINS=LARGE.

 

[Gordon B]

Bruce -- That -3db measurement is not in the manual, but I believe it is 35hz. My room is a high-ceilinged, Florida-style great room open to the dining room, kitchen, foyer and den and even to the great outdoors in the winter when the sliders are open. Best guess is 9,000 cubic feet, which is why I have the two SVS Ultra subs. My Denon X-over is not changeable and is 80 hz. That seems to be working pretty well, though I need to equalize it zince the ART 351 I have seems to have little effect. Probably buy a BFD when I pick up the pre-amp and X-over. What are resistor sets and can you give me a specific Xover recommendation?

 

[BruceD]

The Marchand XM9 and XM9-L crossovers use a small DIP package of resistors to set the crossover frequency for each channel.

If I were you I might buy the 50Hz, 60Hz, and 70Hz, and get the unit sent setup for 80Hz, since it appears you like the way that works now. This way you have a selection. I think they are less than $4 a set. You do need to open the case (6 screws I think) to install the DIP packages.

So if you don't want to do that you can buy the XM6 crossover with a frequency dial you adjust yourself, but it is more expensive. Also, I think it has a bit more noise.

I'm not sure what type of low frequency rolloff your speakers really have, are they bass reflex (with a port)?

I usually start my crossover test an octave above the low frequency -3dB which for you would be 70Hz (based on your 35Hz -3dB spec). But, due to the standing waves caused by room dimensions and the slope of your speaker's low frequency rolloff, it's hard to tell what will work best for you. Which is why you should get a few different frequencies.

 

[Gordon B]

Bruce--the tNTs are two way vented box with the port in back. They go down to 40 at -3 hz. I am not sure what the Xover rolloff is, but I like your idea of buying the different resistor sets. Thanks. I appreciate all the help. Can yu suggest a Web site where I can buy the Xover?

 

[BruceD]

You can find used Marchand xovers on ebay and audiogon.

If you are good with a soldering iron, you can buy the xover in various kit forms or a completed unit directly from the manufacturer Marchand electronics. I gave the website link a few messages back in this thread.

I'd guess somewhere between 50-80Hz would be a workable crossover frequency for those speakers, but you'll just have to experiment to see what works best.