"How To Set Up Subwoofer"...? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 3 Old 03-11-2007, 01:06 PM - Thread Starter
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I've read through this forum, and the speaker forum, and in the reciever forum, but I have not found a good guide on how to get a sub set up "correctly". Now, I understand that a lot of it has to do with room accoustics, and the other equipment. That being said, what I'm trying to achieve is a seamless blend of my sub with my other speakers, such that I can not tell that there is a sub working with them. I do NOT like boomy sound. My preference is a crisp, clear, full range sound for 2 channel stereo music, and authentic reproduction of my movie sound (in 5.1 DTS or DPL). Yes, I like the shake with some movie scenes, and the low rumble of thunder.
So a little background. I have a new Pioneer VSX-84, and Definitive Mythos 1's, 4's, and 8 center. I have a M&K VX1250SFX sub. My room is a typical split level house living room/dining room and open to the stairway - @30' x 15' x 8', fully carpeted. The entertainment center backs up to the stairway, and has a wall on one side and fireplace on the other, so my sub is sitting behind the entertainment center and is effectivly blocked off from the sitting area, but is open to the stairwell. Make sense?? I didnt think so!
I'm connected via sub pre out on the reciever. I also use the Pio's MCACC for setting the speaker levels.
There are three adjustments on the M&K - Phase Control, Low Pass Filter, and Bass Level. When I first run MCACC, what do i set these dials to? My initial try, I set them to the middle setting. But the bass ended up being boomy (this was also set up using THX mode, with 7 speakers set to small, cross over freq was 80hz) for listening to movies and shows, and the sound with stereo was somewhat flat. I removed the extra two speakers, set the subwoofer phase to about 80, and ran MCACC again. I noticed that the reciever reset the speaker settings to large, which flies in the face of everything I've read about home theater set up. Now, the sound through stereo sounds much better (more full range). When watching movies, it lost some of the punch, but it is not as boomy. I feel like I'm just going down a road of trial and error, rather than proceeding with a plan. My criteria is obviously very subjective.
I dont know if what I'm looking for is guidance on the reciver set up, or on the subwoofer, so I'm posting here initially, then I'll try over in the Pioneer thread (everyone there is stuck on some firmware update issue).
So in a couple of summaries:
1) I want good stereo sound and good 5.1 sound. Any tips on how to do this?
2) How valid is the "set speaker size to small" guidance? Or maybe a less subjective question would be, what do I lose by using speakers on Large? Do I lose all of my LFE bass?
3) What should the dials on the sub be set to when utilizing a recievers auto set up feature? My gut is telling me that the bass level should be set to high so that I can get maximum capacity at higher volums/bass levels....but I have yet to try that.
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post #2 of 3 Old 03-11-2007, 03:01 PM
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Originally Posted by JThiessen View Post

2) How valid is the "set speaker size to small" guidance? Or maybe a less subjective question would be, what do I lose by using speakers on Large? Do I lose all of my LFE bass?

Just one comment on the Pioneer's auto set up routine. What I recommend doing is go into the manual speaker set up and change the speakers to small, cross over at 80hz, then go to the MCACC setup area.. you will see an "options" area. Select that and toggle from full mcacc to "keep sp settings." This will not over ride your speaker settings and keep them as small.

The advantage to setting your speakers to small has been covered in great lengths. I recommend doing a google search about bass management and you will find some good info. Briefly though, in theory your subwoofer is better suited to reproducing bass. By setting you speakers to small you are routing all the bass information from the other channels in addition to the LFE to the sub. If you set them to large only the LFE is sent to the sub. Placement is really everything with your subwoofer. Experiment with a few different positions until you find one that has a smooth response. Do a search on here for subwoofer placement and you will find some good tips.
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post #3 of 3 Old 03-11-2007, 03:04 PM
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There is science and then there is what your ears are telling you.

I could repeat the classic advice:

Set all speakers to small. Crossover to the sub at 80hz. Get an SPL meter and a good setup disc and balance all speakers to a given SPL, such as 85 db at your preferred listening point. Forget about any "auto-equalizer" features.

In many cases, that will give you a very good starting point. Some people want a "set and forget-1 setting fits all" arrangement and that will often do it. However, from personal experience not with Pioneer, but Denon's system, I find that the "auto" route is less satisfactory than the SPL meter and test disk.

Now, most modern receivers have individual channel trim controls. Once you have your reference point, you can usually adjust the amount of bass going into sub buy upping or dipping the LFE control on the receiver. Just initially make sure you are using the SPL meter as a spot check to ensure you aren't overdriving the sub.

As for setting a front speaker to "large", the only danger in that is that if you are sending a "bass + LFE" mix to it, it may be possible to overload possibly the receiver's amp as well as the speaker itself. It is usually suggested that they be set to "small" to maximize the amount of amp reserve for the mains, and let the amp in the sub handle the frequencies it is designed for. Unfortunately, there are so many speaker designs out there that blanket statements are typically useless. There are some speaker/receiver combinations that can handle an LFE signal just fine.

As for your question on settings for music vs HT, the above guidelines should work just as well. However, some people prefer to listen to music without the sub. I'm not familair with your specific receiver model, but check to see if there is a type of "pure direct" setting available---and check to see what that does. On some receivers it disables tone controls and possible equalizer settings and sometimes the sub itself.

As for settings like "phase control" on a sub, that is useful if there is bass cancellation happening due to the room/other speaker interaction. Again, the objective is to ensure that you are getting an equalized reference db, such as 85db from all your speakers. Use whatever setting gets you that in your specific situation.
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