Originally Posted by Pulloutchamp
Im a bit new to the sealed game and was drooling through the DSS thread and came across this post. I just got a pair of S3601's, and I am one of the people you mention having one sub firing into the room and the other into the wall. What do you see as "many issues" with this layout? Having read that , I now want to try the longways layout and see if I notice any difference. Anyhow thanks for any input!
One thing to realize with speakers and subs is how much the room plays into the quality of the sound. Here are two scenarios:
1. Top of the line, high quality speaker in a poorly treated room.
2. Decent speaker but in a well treated room.
I would likely pick #2
every time and I've heard several high end speakers in optimized rooms and then the same speaker in rooms without treatments and there is a huge difference. I've also heard my personal speakers in quite a few rooms now as I've taken them to a couple GTGs and it is interesting to notice the sometimes not so subtle differences in their sound in different rooms and setups.
A room also affects subwoofers in the same way. As an aside, if you take a pillow and put it over the front of a tweeter, it will greatly muffle or even block the sound. Put that same pillow in front of a subwoofer and it affects the sound waves very little. The bass has longer wavelengths and travels through materials much better than shorter wavelengths. Well you can get that same affect with a wall and a subwoofer where some parts of the bass wave will go through the drywall while the upper midbass may bounce off of the drywall and back into the room. Now you have a direct radiating front with a rear wave that isn't complete (midbass bounced but low bass didn't) and they will reach the ear at different times. And since most dual-opposed are using a single signal or amp channel, you can't exactly delay the front sub driver to couple correctly with the waves off the wall. This could result in phase issues and may result in some frequencies being boosted and others being canceled out. As another aside, noise canceling headphones work by using a microphone to listen to outside noise and then creating a 180-degree out of phase signal in the headphones so that when the two opposite waves combine in your ear, most of the outside noise is canceled out. So you really want to have phase coherency with all of your speakers and subwoofers to get the best sound. This is also why your receiver asks for speaker/sub distances as it is trying to roughly ensure the sound waves reach your ear at the same time as opposed to being out of phase and canceling/boosting. And realize this phase issue varies over the frequency range so it isn't necessarily an all or nothing. Another, another aside; with your subwoofers playing, walk around the room from the center to the corners and notice how the bass will sometimes disappear and other times be boosted and boomy (corners especially). This is the bass(sound) waves interacting with the room (room modes) and combining and canceling as they bounce off of different objects such as the side and rear walls as well as the floor and ceiling. This is why a treated room can sound so much better than a non-treated room as you can control some of those sound waves bouncing around. And final random brain dump, multiple subs is preferred for most even bass as it ensures more balanced excitation of the rooms modes (https://www.harman.com/sites/default...multsubs_0.pdf
) with 4 subs being nearly optimal while providing the most value (more than 4 subs adds marginal improvement).
Sorry for the various random thoughts but they kept coming and I didn't want to make this post any longer. You have some nice subwoofers there, you just need to work on positioning them optimally. Like I said, BeastAudio had a nice setup with his 4 dual-opposed boxes such that he put them in the front upper and lower corners at a 45-degree angle so one set of woofers bounced off of the front wall and the other set bounced off of the sides walls. Or you could try putting one in the front and the other in back, both facing to the side walls. Or on the sides facing forward/back. But firing one woofer into a hard surface would definitely not be ideal or recommended. And if you put one sub in the rear (closer to the main listening position) and one sub up front (further) you will need to use a receiver with dual sub outputs and something like Audyssey (or other DSP) to ensure the closer sub is delayed properly so that the bass waves from front and back reach your ear at the same time. (You could also use delay on sub amp controls). Hope this helps.