Subwoofer. Great one song. Not so great the next song.


I'm not a subwoofer guy. Played around with one in my primary system (Aerial Acoustics 7Bs, Proceed 250w amp, AR LS-16 tube preamp). Big B&W powered, not sure which. Didn't think it added anything. Ditched it.


Recently got a pair of Aerial Acoustic 6Ts for my secondary system. They have no place to be but right up against the wall. Maybe a foot out. Can't decide if they sound better with a sock in the rear facing bass port or not. Its a wash. Overall they sound pretty dang good though.


But, I played around with a JL Audio e110 sub. Pretty nice unit. Put the socks back in the bass ports.

On some songs the combo with the sub just sounds stellar. On others it sounds boomy and thumpy. My audiophile hang up is taught, clear, concise bass. I do not like boomy and thumpy at all. I can get up and turn the output on the sub down a little and it sounds okay again.

But I don't want to do that every time a different song comes on.

Now, on this sub you can change crossover frequencies, phase and also a polarity switch. I don't know _anything_ about that stuff. I've got it set on the more or less default settings in the manual. The only thing I've messed with is the polarity switch and for reasons I don't understand it sounds better on 180 than 0. I have not messed with the crossover frequency and phase dials.

Is there any chance that changing any of those settings would allow me to reach a sweet spot where I don't have to change settings on the sub frequently? I may or may not keep this sub. If I can't find that sweet spot I'll let it go as alone the 6Ts don't sound bad by any measure.

Thanks,
George


n80

Showing 2 responses by audiokinesis

N80 wrote: " On some songs the combo with the sub just sounds stellar. On others it sounds boomy and thumpy. My audiophile hang up is taught, clear, concise bass. I do not like boomy and thumpy at all. I can get up and turn the output on the sub down a little and it sounds okay again. "

It is not unusual for there to be changes in bass balance from one recording to the next, but I don’t think that’s the whole story.

My guess is that some songs have strong bass energy where you have in-room peaks, and some do not. In-room peaks and dips in the bass region are virtually inevitable. You can re-arrange them by moving the sub and/or moving your listening position. You can reduce their magnitude by a small amount with bass traps. You can significantly improve the in-room smoothness at one location within the room via EQ, with the strong possibility of making the response worse elsewhere in the room.

" The system was meant for casual listening throughout the whole room, not just me alone in one place. That alone is a challenge."

Bass trapping will be beneficial throughout the room, but neither repositioning the sub nor using EQ are especially promising if the goal is significant improvement throughout the room. If you have a problem at a specific frequency throughout the room then of course EQ can be beneficial in addressing that issue. A distributed multisub system is specifically intended to offer significant improvement throughout the room.

I see that you read the article Erik wrote and posted on his website. In it he devotes a fair amount of virtual ink to discrediting the distributed multi-sub concept by labelling its advocates "cultish". If you are open to hearing an opposing viewpoint on the merits of a distributed multisub system, let me know.

"This set up is not my primary system and it is in a formal living room. Just the presence of 4’ tall speakers was quite a concession by my wife."

In that case a distributed multi-sub system is probably impractical, though small subs can sometimes be hidden in unorthodox locations like atop bookshelves.

So assuming that you’ll be plowing with the horses you’ve got for the foreseeable future, here are some setup suggestions:

First, set the level control on your subwoofer amp. This is the control which makes the most subjective difference.

Next, set the lowpass filter frequency control on your subwoofer amp.

Finally, set the phase control on your amp.

Then cycle back through several times to fine-tune.

Sometimes it makes sense to have the sub’s frequency response overlap the bottom end of the mains somewhat, and then put the sub largely if not completely out-of-phase as needed to smooth the transition in that region.

It can take a long time to dial in the level control because the ear is especially sensitive to small changes in SPL at low frequencies. A 3 dB change at 40 Hz is subjectively comparable to a 6 dB change at 1 kHz. This is counter-intuitive but is revealed by the way equal-loudness curves bunch up south of 100 Hz. On the other hand, this implies that small improvements in the in-room frequency response pay disproportionately large perceptual dividends.

If you can try a second (small) sub, positioned far away from and asymmetrically with respect to the first, you may find that it makes a worthwhile improvement in the in-room bass smoothness over a large listening area. And "smooth" bass = "fast" bass, so arguably that would be a step in the right direction, IF you can get away with it.

Duke
subwoofer manufacturer
@erik_squires wrote: 

"Um, sealing will limit the mains and, most importantly, limit driver excursion which is what I was getting to. Even without a filter. Below resonance the port is basically just a huge hole, and the suspension value of the air trapped in the cabinet vanishes." 

I agree.  Sealing the port(s) is certainly worth trying, and if you can avoid having to insert a highpass filter in the signal path going to the main speakers, so much the better. 

If you have multiple ports and can plug some of them, or otherwise lower the tuning frequency to simultaneously get some low-bass contribution while protecting the woofer better than the normal tuning did, that may blend even better with the sub(s).  

Duke