SVS: are my settings wrong, moderate power

[rdfish1]

I have a svs 20-39pci which i thought was pretty good but was never thrilled with the bass. However, after listening to a friends B&W ASW1000, which is inferior per its specs, I am wondering if i don't have my sub set up correctly. The B&W had way more bass than my SVS.

My settings are as follows:

Gain is 50% (straight up), Phase is 90 degrees (whatever that means) and my Crossover is disabled, but is set at 80 hz. My marantz 7200 has been set using the Radioshack soundmeter, and i have the sub at +3. The woofer is set in the corner as directed.

Any ideas? Can my settings be safely adjusted to get more bass?

thx,

dave

[yromj]

Well you COULD turn the gain on the sub up more, but most people who have SVS subs don't even their gains as high as you do. It COULD be a phase issue, but not likely. You may want to try setting it to 0 instead of 90. Do you have your mains set to small or large? If they're set to large is your receiver's "Bass Mix" set to "Both" or "Sub". If it's both, try just sub. Finally how is the sub connected to the receiver? You are using an RCA cable from the LFE out to the sub, correct? Last thing to check, and I realize this SHOULD not be the case, but make sure it's not something like "Night mode" being on or some other type of "limiter" enabled in the receiver.

John

[DrWho]

Sounds like it's more likely an acoustics problem...Ideally, you probably want to consider installing some bass traps in some of the corners (check out the architectural forum for lots of info). If you don't want to spend money, then I might suggest moving the sub around the room. One method to find an ideal location would be to put the sub at the listening position and then crawling around the room looking for where it sounds the best/fullest and then putting the sub in that location.

As far as the settings and all that, feel free to totally crank them to any extremes. If while turning a knob, it starts to sound bad, then stop turning in that direction. As long as you avoid bad sounds, then you probably won't be damaging anything (Things will start sounding bad before they break). I would start by setting your reciever to 0 for the sub channel and then set your phase to 0 and bring up the volume knob on the sub until it sounds the best.

One trick for properly setting the phase on your sub would be to reverse the polarity on your mains (switch the red and black wires) and then turn the phase on the sub until you hear little to no bass on bass heavy music (reversing the polarity causes the mains and sub to cancel out each other). Then reverse the polarity on the mains back to normal and then your sub should then be phase aligned with your mains (now instead of cancellation, you'll get reinforcement). Make sure the reciever is off when switching the cables (wouldn't want to create a short by touching the open wires together) and also make sure that you make adjustments based on the listening position (not when listening next to the sub).

[michael hurd]

Dr who: I am shocked that you are advocating cranking the knobs!

Dave: You did not really compare the units side by side, this is like comparing apples to oranges, or kiwi to grapefruit. Your friend might have the gain cranked on the sub or receiver or both. You did not mention the size of the rooms, so this is another variable. You mention calibration with a slm, was his system calibrated the same way?

[rdfish1]

I will try to respond to some of the questions: My room has 8 foot ceilings and is 20x20 with carpet. The sub is in the corner about 12 feet from my seating area.

My friends BW was not calibrated but I looked at the back and the gain was set at 1/3 power vs. mine at 1/2. I do not know where his receiver was set in terms of individual channels. His room was different in that it was much smaller (1/2) and the floors are tile but the ceilings are 15 feet and the room opens into the kitchen. Not through a door but rather via an open floor plan design so the opening is large.

What does phase do? Is crossover supposed to be disabled? Any other suggestions on why i don't have bigger bass?

[michael hurd]

Relative position of the gain control means nothing, as long as it is calibrated with a test signal and an spl meter. Some receivers put out a hotter signal from the sub/lfe out than others. Ideally, for the best sound to noise ratio, you want the subwoofer setting slightly higher in the receiver, and the gain turned down on the subwoofer amp.

The phase control is very important, if the subwoofer is out of phase slightly with the main speakers, there will be cancellation occurring. Same goes for one main speaker out of phase, you will have weak bass.

Get someone to sit in the listening position with an spl meter, play a bass heavy cd, and turn the phase control for the highest spl. You are then set correctly. With a room of that size you might also be getting some cancellation from reflected low frequencies.

[petergaryr]

After all the other excellent suggestions, there is always the question of source material. The SVS will only give you deep bass if it is truly present in the recording. I have many CDs that sound "thin", or bass-shy. However, if I put on one that has, say an organ pedal that goes down to 20 Hz, the windows rattle.

If you want to be adventurous, you could always try this experiment (which is how I have mine connected): don't use the subwoofer out connection on your receiver. Connect your SVS via the speaker level connections using 14 gauge wire, then your mains to the SVS. Tell your receiver you have "no" subwoofer and your DVD player that you have "no" subwoofer. Set your mains to large and everything else to small. On the SVS, enable crossover and set it at 80 Hz. Set phase to 0. This forces all the bass in any media to be sent to the subwoofer through the mains. LFE is derived this way.

I came up with this arrangement because I have a collection of SACD and DVD-

A recordings. What I found is that in some cases, the subwoofers (I have both SVS 20-39Pci and SVS 20-39 Plus) were not even waking up. I discovered that some Telarc recordings were using the .1 channel for "height" information rather than sub-bass. This connection arrangement solved that. LFE effects on DVDs are still there with no problem.

[DrWho]

And what's wrong with cranking knobs?

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On 8/19/2004 11:46:28 AM michael hurd wrote:

Get someone to sit in the listening position with an spl meter, play a bass heavy cd, and turn the phase control for the highest spl. You are then set correctly. With a room of that size you might also be getting some cancellation from reflected low frequencies.

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I just wanted to mention that this is another method of setting the phase...the only reason I suggested reversing the mains' polarity when adjusting is because it's easier to hear and measure silence versus hearing and measuring differences of only around 3dB. Both methods still work.

For the record, a square room like yours is going to have extreme issues with room nodes. Instead of putting your sub in the corner, I would try placing it along the front wall, about 5-7 feet away from one of the sides (aka, a 1/3 of the way in). Getting the sub out of the corner will reduce your overall SPL, but should help even out your frequency response. you may need to crank the volume on your sub a bit, but you should have plenty of headroom to do that.

To be blunty honest, even with the most optimum placement and adjustment of settings, your bass is still going to be lacking. Room treatment really is the only way that you will be able to actually "fix" the problem. Placement and tweaking are simply methods of minimizing your acoustical problem.

Yet room treatment is somewhat an involved process and it's easy to really screw up the sound. However, I would still strongly recommend purchasing some bass traps and I would even guarantee that when installed right, your room will sound insanely better. You could try the purchasing route and buy some bass traps for around $200, or you could try the DIY route and build some curved masonite panels (costing you much less while at the same time providing diffusion in the mid to high frequencies).

[JewishAMerPrince]

I too once had a 2039pci and was pleased but not thrilled with the sound. Cranking her up just resulted in the speaker bottoming. My listening room is also 20x20 but has a 10 ft ceiling. As it turned out the 2039 pci was just not sufficient for the volume of my listening room because of the size of the room and the fact that there are openings to other parts of the house. Big bass in a big room just requires a lot of horsepower, and the 2039pci, while a fine sub, just doesn't have what it takes to deliver BIG BASS in a big room. So, after consulting with Tom V of SVS, I replaced the 2039 with a PB2+ (skipped the PB2isd which Tom thought would be a bit light) and the sound is now awe inspiring. Just one warning, in the SVS world BIG BASS means a BIG BOX, so if cosmetics are important, you may want to look at other options.