Help with Yamaha receiver crossover...

[kaos]

I'm currently using a Yamaha receiver and noticed in the manual that it refers to all bass frequencies as 90Hz and below and that this is also the low pass filter set on the receiver. Does this mean I should also set my sub to 90 to match the LPF or should I max it out at 200 since the receiver is doing all the filtering? If I max out the sub wouldn't that allow it to receive ALL the bass info from the receiver's LPF? I was worried that if I keep it at 90 that it will cause an extra steep cutoff from the 90 being produced by the receiver. I've read everything on the site in regards to bass management but am still not sure on what do about this. Any advice?

 

[hammong]

Set your crossover in the Yamaha to 90 Hz and either disable the crossover on your subwoofer entirely, or set it to 200 Hz (the highest frequency). You never want to set both crossovers at the same frequency, as it would produce an artificially steep drop-off in frequency response. You need not worry about music content from 90-200 Hz being output from the sub, because the receiver is already taking that data and sending it to your regular speakers.

If you have very good front speakers, and your amplifier allows you to do so, you can set the crossover frequency lower than 90 Hz so that more low frequency bass is produced by the fronts. The THX recommended crossover point is 80 Hz, but lots of people go with 60 Hz with front tower speakers that have good bass response, and even as low as 40 Hz for playing music. For HT use where LFE can be very powerful, I'd stick with 80 Hz and use a good sub to handle everything below 80 Hz.

Which Yamaha do you have? I know the higher end models allow you to mix and match the bass frequencies between the front speakers and the sub. My RX-V2500 has "Front" - "Both" and "SWFR" settings for Bass Out. If you set the output to "Both" then the LFE data is sent to the subwoofer, but all bass content from the Left/Right/Center is sent to BOTH the Subwoofer and Fronts. Personally, I prefer the SWFR setting which sends all bass below the crossover point to the Subwoofer - but I like my sub, a lot. =)

Greg

 

[kaos]

I'm using one of the cheaper models, HTR-5640, and don't have an option to turn off the LPF on the receiver. It's automatically set, unless there's some hack or mod I can do...

The room I'm using for the home theater isn't too big and I didn't need a higher end receiver. I have all my speakers set to small and the sub out set to SUBWOOFER so that the sub will handle everything. The HTR does everything I need it to do and is basic. It's been working great for me. I'm using a 12" sub and the bass is great but I want to make sure I'm getting the best response based on what my system has to offer.

 

[kaos]

Also, i meant to ask, what subwoofer brand/mode/size would you recommend for a small room (14x14) with bad acoustics (a little bit of an echo because of the drywall)? I mean, I want this thing to deliver the goods and blow the house up. I think either my sub is too big for the room, being too close to the listening position no matter where I place it, or I need to invest in some bass traps. ?

 

[kaos]

Wow! I just threw the dial on the sub all the way up to 200Hz and immediately noticed the bass was much stronger and fuller. But in some bass heavy scenes the bass sounds a little flat when it hits the mid and high ranges. This isn't often but I noticed it in a few scenes of the demo I was testing it out with (Matrix Revolutions). The scene before Seraph, Trinity, and Morpheus step out of the elevator, there is a drum roll in the score and it just doesn't sound right, like it isn't being reproduced fully. Also when Smith throws the first, huge slow-mo punch at Neo when they collide in the rain, sounds like it isn't being reproduced fully. I've heard that punch on other subs and the bass just swallows you whole! I just got my sub and I wouldn't think that it's the problem, but rather the acoustics of my room. Would putting up bass traps in the corners help?

I also noticed the further you are away from a subwoofer the smoother it sounds, as if the waves have more room to break before they get to you. Would sound pad absorbers for the walls or the bass traps help this situation in a small room where the listening position is much closer to the sub?

One more thing! How do I know to keep my sub set at NORMAL or REVERSE? What do those 2 settings do exactly (particularly REVERSE)? I have to keep it at one of them on the sub and currently have it at reverse. I did notice though, when using the THX Subwoofer Crossover test on their optimizer that it sounds smoother when set to reverse while the bass sounds as if its dipping high and low when it's on normal.

 

[MDS]

One more thing! How do I know to keep my sub set at NORMAL or REVERSE? What do those 2 settings do exactly (particularly REVERSE)? I have to keep it at one of them on the sub and currently have it at reverse. I did notice though, when using the THX Subwoofer Crossover test on their optimizer that it sounds smoother when set to reverse while the bass sounds as if its dipping high and low when it's on normal.

The phase switch is used to control how the drivers in the sub move in and out in relation to the other speakers to help you get the best blend between the sub and the other speakers.

When it is in the 'normal' position (usually marked 0 degrees), the sub cones move in when the other speakers move in and move out when the other speakers move out - it is in phase with the other speakers.

When in the 'reverse' position (usually marked 180 degrees) the sub drivers are 180 degrees out of phase with respect to the other speakers. In other words, the sub drivers move in when the other speakers move out and move out when the other speakers move in.

Some subs have continuously variable phase settings where you can set it to anywhere between 0 and 180 degrees, rather than only 0 or 180.

The right setting is the one that produces the most bass or sounds the best to your ears. If the sub is behind you, 180 degrees sometimes works best and sometimes you won't notice any difference at all. It really depends on the acoustics of the room. If you change the setting, you need to recalibrate the receiver before you listen to it to decide which setting is best.

 

[kaos]

I'll keep testing it out. Thanks for the help!

 

[hammong]

I've seen the phase make a big difference with regard to subwoofers and room placement. My experience has been that if the sound of the sub is roughly the "same" in the 0 degree and 180 degree settings, that you have a situation where the sub is 90 degrees out of phase and neither the 0/180 setting are exactly right. In that case, you really need to physically MOVE the subwoofer to a different location. Sometimes you only need to move it 1 foot farther out from the wall, sometimes you have to move it across the room.

A good trick that has been mentioned many times here before, is to mount your subwoofer on top of your normal seating location, play a steady rhythmic bass music track, and crawl around on the floor on your hands and knees with your head near the floor. The spot that has the "best" sounding bass while you're crawling around is the precise spot you want to put the subwoofer. Naturally if the best spot is in the middle of the room, you might have to settle for the second or third best spot -- but I guarantee you'll end up with better bass than randomly placing the sub in a place that "looks" good.

Greg