System Setup

Golferdude1977

Here is my home theater system:

Onkyo TX-DS787 Receiver
Onkyo DV-C601 DVD Player
Velodyne CT-100 Sub
Polk RT-35 Fronts
Polk CS-245 Center
Polk RT-25 Rear
Sony 36" XBR TV

I have been reading on how to set things up on here. I am not all that familiar with how the sub is best set up. I was hoping for some guideance. Thanks...

Golferdude

pjdami

Hello, Happy New Year, and welcome to Club Polk. You have almost the same system I started off with in Home Theater including the TV.

Set all speakers to small on your Onkyo with a crossover of 80 hz. Use the LFE sub out on the receiver to your sub. You will need a subwoofer cable for this. Monster makes a few good ones. Keep the LFE setting on the Onkyo to 0 but put your subwoofer level at -3 db to -5 db to minimize gain distortion from your receiver to the sub.

It helps to have the Avia or Sound and Vision Calibration DVD to appropriately set your mains and surrounds and also set the level gain of your subwoofer. The noise level generator in the receiver is not as accurate as the DVDs. You will also need a SPL meter that you can purchase from Radio Shack.

If you do not want to purchase the calibration DVD and the SPL meter you can of course do it by ear but often times this can lead to the sub being +10 db too high (in my first attempt at least).

Most of us here set our sub at the sub amp gain level control to +3 to +5 db "hot" for listening to movies and 0 db for music. This is done by comparing the SPL of one of your main speakers to the SPL of the sub and setting the level on the sub a few dbs "hot".

Hope this helps. Ask away if you have more questions.

Paul

Golferdude1977

Thanks Paul..and Happy New Year to you too.

I do have the Avia DVD and a RS SPL meter. And I am using the LFE sub out on the receiver to the sub. I ran through the Avia DVD last night and that is why I ended up asking about the setup.

It seems when I would check the SPL on the various speakers compared to the sub, it would vary from speaker to speaker. I am not sure if this is how it is suppose to be or not.

Plus, I am not sure how I should have the switches on the sub, the Phase switch and the crossover switch.

I think I set the receiver to a -5 on the sub level and used the sub volume level to adjust the SPL reading.

You mentioned that I should use a crossover of 80 hz. Where do I set this?

Also, you mentioned that most set the sub amp gain level to +3 to +5 db "hot" for movies. Is this on the receiver level setting?

I guess I am def. a rookie at this...but overall the system sounds good. Just trying to tweek it to the max.

Thanks...

Jimmy

pjdami

You are very welcome Jimmy. By the way I love to golf too:)

Just trying to tweek it to the max.

Well you have the Avia disk and a SPL meter so you are well on your way.

It seems when I would check the SPL on the various speakers compared to the sub, it would vary from speaker to speaker. I am not sure if this is how it is suppose to be or not.

Dr. Spec helped me with this same question a week or two ago. Here's what he said to do:

The best way to check all of the differences in the surround channels is to power down the subwoofer and run the Avia (or S&V) sub test tone for each channel and note the results.

If you like your bass hot, pick the surround channel that has the lowest reading with the sub powered down and then use it to calibrate the subwoofer.

I think I set the receiver to a -5 on the sub level and used the sub volume level to adjust the SPL reading.

Yes that is correct.

You mentioned that I should use a crossover of 80 hz. Where do I set this?

Do this on the Onkyo settings.

Also, you mentioned that most set the sub amp gain level to +3 to +5 db "hot" for movies. Is this on the receiver level setting?

Using the Avia disk and after checking the level of all your surrounds with the sub turned off pick the surround that is the lowest and calibrate your sub using the sub amp gain until it reads +3 db "hotter" than the surround.

Plus, I am not sure how I should have the switches on the sub, the Phase switch and the crossover switch.

The phase switch is something that you will have to experiment with. Pick the setting that sounds like produces the most bass. A more systematic approach can be had by playing a 80 hz test tone and recording the SPL then flip the phase switch and see which one is louder. That is the setting that you want to use.

You may find these two threads very informative and you may want to do some room FR sweeps with your system as well:

http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=14847

http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=14932

You can download the mp3 of the 1/12 octave frequency sweeps here and burn a cd:

http://beyond_gomer.tripod.com/

As for your sub switch setting, I am not too familiar with the Velo subs but my Hsu sub has an In / Out switch. Since you are going to use the receiver 80 hz crossover I would chose the setting referred by the Velodyne manual that disables the subs internal crossover since it is being done by the receiver. Some frequency sweeps will let you know if you have it correct.

Hope this helps you out some more and happy tweaking.

Paul